Model 857 Redox Cell Test System - Scribner

Scribner Associates Incorporated

OPERATING MANUAL

Model 857

Redox Cell Test System

MODEL 857 REDOX CELL TEST SYSTEM

© Copyright 2012

Scribner Associates, Inc.

Southern Pines, North Carolina

All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored

on a retrieval system or translated into any language, in any form or by any means, electronic,

mechanical, manual or otherwise, without the prior written consent of Scribner Associates, Inc.

Scribner Associates, Inc. makes no representations or warranties with respect to the contents hereof

and specifically disclaim any implied warranties of merchantability and fitness for a particular

purpose. Furthermore, Scribner Associates, Inc. reserves the right to revise this publication and to

make changes from time to time in the content hereof without obligation to notify any person of

such revision or changes.

SAFETY

This equipment and software must be operated and maintained only by trained

and qualified persons familiar with safe laboratory techniques. All users should

have adequate training and knowledge of the hazards associated with the use of

hazardous chemicals, pressurized gasses and all applicable laboratory

techniques before operation of this equipment.

MODEL 857 REDOX CELL

TEST SYSTEM

OPERATING MANUAL


150 E. Connecticut Ave.

Southern Pines, North Carolina, USA 28387

Phone: 910-695-8884, Fax: 910-695-8886

E-mail: [email protected]

Support: [email protected]

Website: www.scribner.com Rev. C (11/2011)

CHAPTER 1 - INTRODUCTION .................................................................................................. 1

1.1. System Requirements................................................................................................... 2 1.2. Technical Support ........................................................................................................ 2 1.3. Chapter Summaries ...................................................................................................... 3

CHAPTER 2 - SAFETY ................................................................................................................. 5

2.1. General ......................................................................................................................... 5

2.2. Material Safety Data Sheets ......................................................................................... 5 2.3. Computer Control and System Safety.......................................................................... 5 2.4. Grounding .................................................................................................................... 6 2.5. AC Supply Voltage ...................................................................................................... 6 2.6. Fuses ............................................................................................................................ 6

2.7. Avoid Unsafe Equipment ............................................................................................. 6

2.8. Live Conductors ........................................................................................................... 6

2.9. Equipment Modification .............................................................................................. 7

CHAPTER 3 - SYSTEM DESCRPTION & INSTALLATION .................................................... 9

3.1. General Description ..................................................................................................... 9 3.2. Potentiostat Ratings ..................................................................................................... 9

3.3. AC Power Requirements.............................................................................................. 9 3.4. 857 Controller Controls and Connections.................................................................. 10

3.4.1. 857 Controller Front Panel - Figure 1 ...................................................... 10

3.4.2. Rear Panel - Figure 2 ............................................................................... 12 3.5. Electrical Connections ............................................................................................... 13

3.6. USB Connections ....................................................................................................... 13 3.7. Flow Bench - Figure 3 ............................................................................................... 13

3.8. Flow Cell Test Fixture ............................................................................................... 15

CHAPTER 4 - SYSTEM COMPONENTS .................................................................................. 19

4.1. System Components................................................................................................... 19 4.2. Terminology – Polarity Convention and Designations .............................................. 19 4.3. Reactants and Flow Control - Figure 6 ..................................................................... 19 4.4. Purge Gas ................................................................................................................... 20

4.5. Potentiostat ................................................................................................................. 20 4.6. Data Acquisition ........................................................................................................ 21 4.7. System Software ........................................................................................................ 21

CHAPTER 5 - GETTING STARTED & OPERATION .............................................................. 23

5.1. Preparation of Reactant, Gas and Electrical Connections ......................................... 23 5.2. Check List Before Proceeding: .................................................................................. 23 5.3. Apply AC Power ........................................................................................................ 23

5.4. Storage and Shipping ................................................................................................. 24

CHAPTER 6 - DETAILED SPECIFICATIONS ......................................................................... 25

6.1. Features ...................................................................................................................... 25 6.2. Specifications ............................................................................................................. 25

CHAPTER 7 - TROUBLESHOOTING ....................................................................................... 29

7.1. Communication Problems .......................................................................................... 29

TABLE OF CONTENTS

7.2. Hardware Problems .................................................................................................... 29

CHAPTER 8 - SWAGELOK® TUBE FITTING INSTRUCTIONS ............................................ 31

8.1. Assembly Instructions for Standard Swagelok Metal Tube Fittings ......................... 31

8.2. Gageability ................................................................................................................. 31 8.3. Reassembly Instructions ............................................................................................ 32

CHAPTER 9 - FLOWCELL SOFTWARE INSTRUCTIONS .................................................... 33

9.1. Software Installation .................................................................................................. 33 9.1.1. Installing FlowCell Software: .................................................................. 33

9.2. Starting the FlowCell Software .................................................................................. 34 9.3. Setup Cell Menu ........................................................................................................ 34 9.4. Set-up Flow Menu...................................................................................................... 35 9.5. Main FlowCell Window ............................................................................................ 35

9.5.1. Control Buttons ........................................................................................ 36

9.5.2. Data Values .............................................................................................. 37 9.6. Background ................................................................................................................ 37

9.7. Graphs ........................................................................................................................ 38

9.8. Flow Select Menu ...................................................................................................... 39 9.8.1. Purge System / Drain Cell - Figure 8 ....................................................... 41 9.8.2. Fill Tanks – Figure 9 ................................................................................ 42

9.8.3. Operate Mode - Figure 10 ........................................................................ 43 9.8.4. Drain Cell and Tank - Figure 11 .............................................................. 44

9.8.5. Flush Cell and Pump - Figure 12 ............................................................. 45 9.9. Experiments ............................................................................................................... 46

9.9.1. Open Circuit ............................................................................................. 47

9.9.2. Constant Current ...................................................................................... 49 9.9.3. Constant Voltage...................................................................................... 51

9.9.4. Scan Current ............................................................................................ 53 9.9.5. Scan Voltage ............................................................................................ 56

9.9.6. Controlled Current Impedance................................................................. 59 9.9.7. Controlled Voltage Impedance ................................................................ 61

9.9.8. Change Cell.............................................................................................. 63 9.9.9. Change Flow ............................................................................................ 64

9.9.10. Run External Utility ............................................................................... 65 9.9.11. Repeat Loop ........................................................................................... 66

CHAPTER 10 - FLOWCELL DATA AND FILE FORMATS .................................................... 67

10.1. Data Value Definitions ............................................................................................ 67 10.2. Data File Format ...................................................................................................... 68

10.3. Analyzing Impedance Data ...................................................................................... 71

APPENDIX A – ROTOMETER DATA SHEET ......................................................................... 73

Chapter 1 Introduction

1

CHAPTER 1 - INTRODUCTION

This manual describes the installation, configuration, and operation of the Model 857

Redox Cell Test System with FlowCell software. The combination of this hardware and software

provides a complete system for testing the characteristics and operating parameters of various

types of electrochemical flow cells or redox flow batteries.

The 857 Redox Cell Test System provides a high level of real-time control and safety

monitoring using advanced hardware design. The 857 consists of two main components: the 857

Controller and the 857 Flow Bench.

The 857 Controller permits full control and/or measurement of the all key elements of the

flow cell, including the fluid flow rate and temperature, cell temperature, electrical parameters

such as voltage and current, and communication with the host PC and FlowCellTM

software. The

857 Controller includes a high-current, multi-range potentiostat which can switch between

current ranges to maximize the flexibility and accuracy of the test station.

The 857 Flow Bench connects to the 857 Controller and comprises the flow cell support

hardware such as precision peristaltic pumps, electrolyte storage tanks, purge gas connections,

valves and tubing.

As an option, the 892e Data Expansion Module can be used with the 857 to increase the

available monitoring channels. The 892e provides a means of real-time monitoring of

temperature, voltages and/or other parameters (e.g., pressure) of the flow cell and flow cell test

system. The Model 892e is intended primarily for use with test systems based on Scribner

Associates’ Model 840, 850e and 890e Fuel Cell Test Systems and the 857 Redox Cell Test

System. The Model 892e is controlled through the RS485 serial interface of the Model 857

Controller.

With the Model 857 and FlowCell software you can:

Control the liquid reactant electrolyte flow rate and temperature.

Control a purge gas for the negative and positive electrode reactants and storage

tanks.

Control the temperature of the flow cell.

Scale the flow cell operating parameters for area, current, voltage, power, and

number of cells.

Control and/or measure current or voltage of the flow cell under test.

Perform current-controlled or voltage-controlled experiments including constant,

scanned and stair-step measurements.

Monitor performance over a wide range of time intervals.

Display data using a variety of axis formats.

Measure flow cell characteristics such as ohmic or internal resistance, polarization

resistance, polarization behavior (V-I curves), charge/discharge characteristics,

and state-of-charge based on OCV of a secondary cell.

Apply a controlled charge/discharge sequence to a cell to simulate a variety of

operating conditions.

Save data files and experimental setup parameters.


2

Optimize experimental parameters for maximum measurement capability.

Perform electrochemical impedance spectroscopy (EIS) and high-frequency

resistance (HFR) under operating conditions.

1.1. System Requirements

Model 857 Redox Cell Test System - 857 Controller, 857 Flow Bench

Model 892e Data Expansion Unit (Optional)

Pressurized purge gas (e.g., N2)

Purge gas vent

Liquid reactants - Negative Electrode and Positive Electrode Electrolytes

Flow cell test fixture

FlowCell Software

Windows PC/compatible computer with minimum system requirements

o 1 GHz or greater Pentium or equivalent processor

o Microsoft Windows 2000/XP Pro/Vista/Windows 7 (32-bit version recommended

for Windows 7 systems)

o 512 MB RAM

o 10 GB available hard disk space - data file dependent

o CD ROM

o 1 available USB Port

o Or greater specifications as required by the operating system used

1.2. Technical Support

Please review the Installation and Start-up portions of this manual prior to calling for

support. Users of FlowCell software can receive technical assistance through the following

sources:

Contact your sales agent or the factory:


150 E. Connecticut Ave.

Southern Pines, North Carolina, USA 28387

Telephone: 910-695-8884

Fax: 910-695-8886

E-mail: [email protected]

mailto:[email protected]


3

1.3. Chapter Summaries

CHAPTER 1. INTRODUCTION

Provides an overall description of the Model 857 Redox Flow Cell Test System and FlowCell

software.

CHAPTER 2. SAFETY

Describes basic safety issues pertaining to operation of the 857 Redox Cell Test System and flow

cells.

CHAPTER 3. SYSTEM SPECIFICATIONS AND HARDWARE INSTALLATION

Explains how to install and connect the Model 857 Redox Cell Test System and the flow cell test

fixture electrical connections.

CHAPTER 4. SYSTEM COMPONETS AND CONFIGURATION

Describes the Model 857 Redox Flow Cell Test System components.

CHAPTER 5. GETTING STARTED AND OPERATION

Steps the user through start-up of the flow cell test hardware and discusses setting parameters,

system operating procedures, and taking measurements with a flow cell.

CHAPTER 6. 857 DETAILED SPECIFICATIONS

Describes the Model 857 Redox Cell Test System and its specifications.

CHAPTER 7. TROUBLESHOOTING

Provides solutions for common connection, startup, and operation problems.

CHAPTER 8. SWAGELOK® TUBE FITTING INSTRUCTIONS

Describes installation procedure and use of Swagelok fittings.

CHAPTER 9. FLOWCELL SOFTWARE INSTRUCTIONS

Describes FlowCell software operation.


4

Chapter 2 Safety

5

CHAPTER 2 - SAFETY

IMPORTANT SAFETY NOTICE

Users of this equipment should review all of the following material and other

safety standards deemed appropriate and apply all safety standards that may

be required in the user’s facility before proceeding. Safe operation of a flow

cell is the responsibility of the end user of this equipment and may not be

limited to the items below.

2.1. General

It is required that this equipment be operated only by trained and qualified persons

familiar with flow cell technology and safe laboratory techniques. All users should have

adequate training and knowledge of the hazards associated with the use of the relevant

chemicals and pressurized gasses, and all applicable laboratory techniques before

operation of this equipment.

The equipment described in this manual is supplied in a safe condition. To avoid injury to

an operator, the safety precautions given below and throughout the manual, must be strictly

adhered to whenever the equipment is operated. For specific safety details, please refer to the

relevant sections within the manual.

The equipment is designed solely for electronic measurement of an operating flow cell

and should not be used for any other purpose. Scribner Associates accepts no responsibility for

accidents or damage resulting from any failure to comply with these precautions.

2.2. Material Safety Data Sheets

It is recommended that all applicable material safety data sheets (MSDS) be read and

understood before proceeding. In the United States, the law requires that the vendor provide a

MSDS with each furnished chemical supply. MSDS are a required part of hazardous material

handling.

2.3. Computer Control and System Safety

Precautions should be taken to ensure sustained operation of the PC controlling the

Model 857. The use of an uninterruptible power supply is recommended to ensure continuous

electrical power to the PC used for the test system. If the electronics lose main power, an

automatic shutdown of the load and reactant flow will result. Operators are strongly

recommended to evaluate the operation and safety of the whole test system and laboratory

environment before performing any long term or unattended tests.

Chapter 2 Safety

6

2.4. Grounding

The equipment described in this manual relies on the connection of a protective

conductor to earth ground for equipment and operator safety. The power cable of the equipment

should only be inserted into an outlet that has the required earth ground contact. The protection

must not be disabled through the use of a two-conductor extension cord, an adaptor that does not

maintain earth ground continuity, or any other type of connection that does not maintain earth

ground continuity. The ground prong of the power cable must not be cut off or otherwise

modified.

2.5. AC Supply Voltage

Before first connecting the power to the equipment, make sure that the line voltage is

100-120 V at 50-60 Hz. (Note: 220 V option is available at the time of ordering.) Never operate

the equipment from a line voltage or frequency other than that specified. Install the 857

Controller such that access to the power switch located on the front panel is not obstructed.

WARNING! The equipment may be damaged by the application of incorrect line voltage.

DANGER! Voltage and current conditions inside the equipment described in this manual are

sufficient to cause injury and possibly death. Only qualified technicians should be

permitted to remove the cover, attempt repairs, or connect the unit to the external

gas distribution equipment.

2.6. Fuses

The rating of the AC line fuse (in the power inlet connector) must agree with the value

stated in Chapter 3.

2.7. Avoid Unsafe Equipment

The equipment may be unsafe to install or use if any of the following statements apply:

Equipment shows visible damage.

Equipment fails to perform properly.

Equipment has been subjected to prolonged storage under unfavorable conditions.

If there is any doubt as to the serviceability of the equipment, do not use it. Get it

properly checked out by a qualified service technician. If this equipment is used in a manner not

specified by Scribner Associates, the safety protection provided by the equipment may be

impaired.

2.8. Live Conductors

Opening the cover or removing of parts from this equipment could expose live

conductors. The equipment must be disconnected from all power and signal sources before it is

opened for any adjustment, replacement, maintenance, or repair. Adjustments, maintenance, or

repair must be done only by a qualified technician.

Chapter 2 Safety

7

2.9. Equipment Modification

To avoid introducing safety hazards, never install non-standard parts in the equipment, or

make any unauthorized modification. To maintain safety, return the equipment to Scribner

Associates for service and repair.

Chapter 2 Safety

8

Chapter 3 System Specifications & Hardware Installation

9

CHAPTER 3 - SYSTEM DESCRPTION & INSTALLATION

3.1. General Description

This chapter lists the specifications of the Model 857 and describes its installation, and

electrical, communication (USB), and gas connections.

The 857 Redox Cell Test System is a complete test station for operation and

measurement of redox flow cells and flow batteries. The 857 combines a computer-controlled

analytical instrument, multi-range programmable potentiostat, reactant flow and temperature

controls, and data acquisition functions, with pumps and other reactant handling hardware in an

integrated and compact bench-top unit.

The 857 has a state-of-the-art liquid reactant handling system that features independent

negative (anolyte) and positive (catholyte) electrolyte reactant flow paths and storage reservoirs

and purge gas, safety alarms, and check valves to prevent system contamination.

The 857 and FlowCell software permit long term performance testing of a redox single

cell flow cell or small stack under user defined conditions, coupled with real time monitoring of

the whole cell and half-cell potentials, ohmic-resistance corrected whole and half cell potentials,

current, power, internal resistance, reactant flow rate, and cell and reactant temperature.

3.2. Potentiostat Ratings

The ratings given below are for nominal flow cell outputs. Note that flow cell open

circuit voltages (OCV) must fall within the maximum voltage ratings of the 857 potentiostat.

Current, A

Max. Power, W Max. Voltage, V ±7, ±0.7, ±0.07 21 ±3.0

3.3. AC Power Requirements

100-120 VAC / 50-60 Hz, 10 A maximum*

* 220-240 V operation is available as an option at the time of ordering


10

3.4. 857 Controller Controls and Connections

NOTE: COOLING AIR INTAKE AND EXHAUST

Cooling air for the 857 Controller enters through bottom and right side of the case and exits

through the left side of the case. Allow at least 30 cm (12 inches) of clearance on either side of

the unit and do not obstruct air flow around the lower edges of the case to ensure adequate air

flow.

Do not place this instrument in a fume hood and avoid corrosive atmospheres.

3.4.1. 857 Controller Front Panel - Figure 1

Power Switch

Controls the AC line power to the Model 857 Controller.

Emergency Stop - Press the RED BUTTON to activate

Pressing this switch removes power to the 857 Flow Bench pumps (i.e., stops flow),

removes heat from the electrolyte storage tanks and cell, and disconnects the potentiostat from

the cell (turns cell OFF so that current is zero). If this switch is pressed while in operation, the

FlowCell software will display an alarm condition on the screen to notify the user that the fuel

supply has been shut off.

Turn button clockwise 1/8 turn to reset. Note arrows on button. Do not force.

Temperature Controllers

The Anode (Negative Tank), Cathode (Positive Tank), and Cell temperature controllers

are used to monitor and control the temperature of anolyte (negative side solution), catholyte

(positive side solution), and cell body, respectively. The set points, read back, and alarms are

controlled by FlowCell. These temperature controllers are programmed at the factory, and the

user should not alter their internal settings. DO NOT enter temperature set point values from the

front panel of the controllers.

Figure 1 – 857 Controller front panel.


11

857 Cell Cable and Connector

The cell cable provides electrical connection of the potentiostat to the flow cell. The cell

cable connects to the 857 Controller through the Cell Interface connector on the front of the 857

Controller.

It is important to use only the cable provided with unit for connection to the flow

cell. Failure to use the furnished cell cable will reduce the performance of the 857 and/or flow

cell.

The potentiostat has a MAXIMUM VOLTAGE rating at its terminals and should

not be subjected to input voltages (applied to the main current or voltage sense terminals)

in excess of ±3 V. Any cell used must be electrically isolated from earth ground (including

metal chassis of instrument). This is best done by operating the cell in the supplied plastic drip

tray as shown in Figure 3. Damage to the electronics can result if these precautions are not

followed, which may require that the 857 be returned to the factory for repair.

The 857 Cell Cable includes the following leads:

Main Leads – Positive Current (+I) and Negative Current (-I)

Whole Sense Leads – Positive Voltage Sense (+V) and Negative Voltage (-V)

Auxiliary Voltage - Positive Aux (+Aux) and Negative Aux (-Aux)

State-of-Charge (SOC) Sense Leads - Positive SOC (+V) and Negative SOC (-V)

The Negative Whole Sense lead MUST be connected directly to the negative end plate or

current collector of the flow cell because it provides a reference point for all flow cell potential

measurements.

The Negative Auxiliary Sense leads may be connected to an internal reference electrode

if desired and the Positive Auxiliary Sense connected to either the Negative or Positive end plate

depending on the electrode of interest. Alternatively, the Auxiliary Sense leads can be connected

to a single cell or subset of cells within a stack.

Cell Thermocouple Connector and Heater Outlet

The Cell Heater Outlet provides 120 VAC at up to 200 W for powering the flow cell

heater (220 volt model provides 400 watts at 220 V from an IEC320 outlet). The positive and

negative cell electrodes must be electrically isolated from the heater using electrical insulation

from an earth grounded metal part between the heater and electrodes or at least two insulation

systems with ratings suitable for the heater voltage must be used between the live heater element

and the cell electrodes. Any substantial metal parts of the cell not connected to the cell

electrodes (including the shell of cartridge-type heaters) should be earth grounded through the

heater cable ground wire. The grounding and insulation systems of the cell should be checked

periodically to prevent operator hazards and damage to the test system.

A thermocouple input and a temperature controller are provided to regulate and control

the temperature in the cell. A standard Type T (blue) thermocouple with miniature OMEGA

brand (blue Type T) male connector is required. The cell thermocouple should be appropriately


12

installed in the flow cell and connected to the thermocouple jack on the front of the 857

Controller.

3.4.2. Rear Panel - Figure 2

Figure 2 –857 Controller rear panel.

AC Power Connector

The Model 857 is supplied with a standard IEC power input socket and filter for

connection to 100-120 VAC, 50-60 Hz.

A 3AG size time delay fuse should be in the AC line fuse holder which is part of the

input socket. The fuse rating is 10 A. To replace the fuse, carefully open the holder and remove

the red insert. Before replacing, determine the reason for failure of the fuse, such as a shorted

flow cell heater. Reinstall in the same position with a new fuse after the problem has been

corrected.

USB Interface The USB port connects the 857 Controller to a compatible PC for control and data

acquisition by the FlowCell software.

Anode (Negative Tank) and Cathode (Positive) Tank Thermocouple Connectors

These are for connecting the 857 Flow Bench tank thermocouples in order to measure

and control the Anode (Negative Tank) and Cathode (Positive) Tank temperatures.

Warning: Do NOT reverse or exchange these two connections. This will result in

loss of heating control and potential damage to the electrolyte tanks on the 857 Flow Bench.

892 Com Input

This serial port connects the 857 Controller to an 892e Data Expansion Module. Use the

furnished serial cable.

892 Power Supply If used, the 892e is powered through the 857 Controller. Use the included IEC male-to-

female power cable to connect to the AC power connector on the rear of the 892e.


13

Pump Interface

The pump control signals and power are provided from the 857 Controller to the pumps

in the 857 Flow Bench through this cable and interface. Attach the cable that is attached to the

857 Flow Bench to this connector.

Tank Heaters Interface

Power for the tank heaters on the 857 Flow Bench is provided from the 857 Controller

through this cable and interface. Attach the cable that is attached to the 857 Flow Bench to this

connector.

3.5. Electrical Connections

If 220-240V AC 50-60 Hz power is available, the 857 may be configured to operate on

220-240V at the time of manufacture. Otherwise you must use a step-down transformer of

appropriate capacity to supply 120V AC to the 857.

It is recommended that a UPS device be used to avoid test interruption in the event of a

power glitch.

3.6. USB Connections

A USB cable is necessary to interface the computer and the 857 Redox Test System.

Connect the 857 Controller to the computer with the furnished USB cable.

3.7. Flow Bench - Figure 3

The 857 Flow Bench provides the supporting hardware needed to operate the flow cell.

The flow bench includes two independently-controlled pumps, two electrolyte reservoirs with

heaters and thermocouples, purge gas input and outlet to a vent with manual flow rate control

and connections. All components are non-metallic.

The pumps and heating of the tanks is controlled through the 857 Controller and

FlowCell software. Operation of the purge gas flow rate is manually using the respective

rotometers. Likewise, operation of the upper and lower three-way valves on each tank are also

manual. The valves in combination with the direction of the pump (clockwise or counter-

clockwise) are used to control the flow mode of the cell.

IMPORTANT!

The 857 Flow Bench is composed of two independent flow paths. Facing the

front of the 857 Flow Bench, the LEFT side is designated the Negative Side

and should contain the anolyte solution (Negative Electrolyte) and feed to the

negative side of the flow cell. The RIGHT side is designated the Positive Side

and should contain the catholyte solution (Positive Electrolyte) and feed to the

positive side of the flow cell.


14

See also Figure 6 for a schematic of the 857 Flow Path.

The 857 Controller and FlowCell software are designed for this configuration

and the system should not be used in a reverse configuration.

The system should be used with the drip tray as shown in Figure 3. The cell should be

placed inside the drip tray.

Materials of construction for the wetted parts of the system are polyvinyl chloride (PVC),

polypropylene (PP), and perfluoroalkoxy (PFA).

The maximum operating temperature of the tanks is 50

oC.

The Tank Heater Interface Cable, Pump Interface Cable, and Negative Tank (Anode) and

Positive Tank (Catholyte) thermocouples should be connected to the rear of the 857 Controller

prior to start-up and operation. Note that all power and control of the 857 Flow Bench

components is via the Tank Heater Interface and Pump Interface cables.


15

Figure 3 – 857 Flow Bench.

3.8. Flow Cell Test Fixture

The 857 electrical connections consist of a set of cables to carry the cell current and sense

lead connections to measure voltage of the cell. Leads must be attached directly to the cell

terminals for accurate measurement. All flow cells have at least two electrical connections: the

negative electrode and the positive electrode.

The 857 cell cable assembly attaches to the Cell Interface connector on the front of the

857 Controller. Leads are furnished with a banana plug which may be replaced with termination

suitable for the cell. Independent current and voltage inputs are provided for accurate

measurement of the voltage at the cell end plates or current collectors.

It is very important that these leads be used and connected properly. Cell voltage

and internal resistance measurements are performed between the sense leads, so their placement

on the cell end plates will affect the actual readings.

NEGATIVE (-) SIDE POSITIVE (+) SIDE


16

The cell cable leads are labeled as follows:

Label Color Description

I + Red Positive current

I - Black Negative current

V + Red Positive whole voltage sense

V - Black Negative whole voltage sense

Aux + White Positive auxiliary voltage sense

Aux - Green Negative auxiliary voltage sense

SOC + Red Positive SOC voltage sense

SOC - Black Negative SOC voltage sense

Two-terminal Cells: Connect the negative (I-) and positive (I+) cell current leads to the negative

and positive end plates (current collector) of the flow cell or stack. Connect the whole cell

negative voltage (V-) and whole cell positive voltage (V+) sense leads to the negative and

positive end plates (current collector) of the flow cell or stack. The Auxiliary sense leads are not

used in this configuration and should be connected to the cell along with the V- lead.

Figure 4 - Configuration for a 2-terminal cell connection using only the current leads and

the whole voltage sense leads. The auxiliary sense leads are not used in this configuration.

The SOC leads may be attached to a separate cell for SOC measurement.

- +

I-

(black)V-

(black)I+

(red)V+

(red)

SOC + (red)SOC - (black)Aux + (white)Aux - (green)

857 Cell Cable


17

Three-terminal cells: Some cell configurations may incorporate a reference electrode, therefore

permitting 3-electrode measurements. In addition to whole cell measurement between the

negative and positive end-plates or electrodes, the reference electrode permits half-cell

measurements of either the negative electrode reactions or the positive electrode reactions.

As for the 2-terminal connection, connect the negative (I-) and positive (I+) cell current leads to

the negative and positive end plates (current collector) of the flow cell or stack. Connect the

whole cell negative voltage (V-) and whole cell positive voltage (V+) sense leads to the negative

and positive end plates (current collector) of the flow cell or stack.

Connect the negative auxiliary voltage sense (Aux –) to the reference electrode. Connect the

positive auxiliary voltage sense (Aux +) to the end plate (current collector) of the negative or

positive side of the cell, depending on the electrode of interest.

Figure 5 - Configuration for a 3-terminal cell connection with reference electrode located

on the negative side of the cell for half-cell measurements of the positive side electrode.

CAUTION: The potentiostat has a MAXIMUM VOLTAGE rating at its terminals and

should not be subjected to input voltages (applied to the current or sense

terminals) in excess of ±3 V. Damage not covered by warranty may result to

the potentiostat.

- +

I- V- I+V+

SOC + (red)SOC - (black)

Aux+Aux-

Ref

857 Cell Cable


18

Chapter 4 System Components

19

CHAPTER 4 - SYSTEM COMPONENTS

4.1. System Components

A basic setup to test a flow cell requires the following items:

A reactor or cell, commonly referred to as a flow cell, single cell or stack.

A supply of reactants and control of the flow of those reactants to the cell.

A method of sourcing (charging) and sinking (discharging), controlling and

measuring, electrical energy and power to and from the cell.

A data acquisition system to capture all the flow cell operating parameters.

System software for controlling the test system and all of its components.

4.2. Terminology – Polarity Convention and Designations

By definition, electrochemical oxidation takes place at an anode and electrochemical

reduction reaction takes places at a cathode. Therefore, during operation of a flow cell both the

negative electrode and the positive electrode are anode and cathode, depending on the mode of

operation, i.e., during charging vs. discharging. The negative electrode is an anode during

discharging and a cathode during charging. Likewise, the positive electrode is a cathode during

discharging and an anode during charging. For this reason, we avoid calling the electrodes the

anode and cathode as is commonly done with fuel cells.

Electrode Operation Reaction

Negative Electrode Discharge (Anode) A A+z

+ ze-

Charge (Cathode) A+z

+ ze- A

Positive Electrode Discharge (Cathode) B+y

+ ye- B

Charge (Anode) B B+y

+ ye-

Species A and B and their various oxidation states are specific to the flow battery of

interest. Note that species A and B maybe complexes, negatively or positively charged, or

electrically neutral.

The convention used by for the 857 and FlowCell software are that positive currents

indicate charging of the system (energy put into the cell/reactants) and negative current

discharging of the system (sinking energy from the cell).

Based on this convention, on charging via application of a positive current, the cell

voltage increases (becomes more positive) relative to the open circuit voltage (OCV). Likewise,

the cell voltage decreases (becomes less positive) relative to the OCV upon discharging through

application of a negative current.

4.3. Reactants and Flow Control - Figure 6

In a flow cell, liquid reactants must be delivered to the two halves of the cell. To facilitate

this, the 857 Flow Bench includes two (2) independently-controlled peristaltic pumps, of which


20

the direction (forward or clockwise, and reverse or counter-clockwise) and rate are controlled

through the FlowCell software. The pumps are connected to the 857 Controller through the

Pump Interface Connector located on the back 857 Controller.

4.4. Purge Gas

The 857 Flow Bench includes provisions for a purge gas (e.g., N2) for de-aeration and

purge gas blanketing of the electrolytes. The purge gas flow rate is controlled by manually-

operated rotometers located to the right of the electrolyte reservoirs. The rotometer flow rate

scale is shown in Table 1 and the data sheet is reproduced in Appendix A.

Purge gas inlet and outlet ports use check valves to prevent back-flow of gas into the

purge gas source and ingress of air through the purge gas vent.

The purge gas outlets are labeled “To Vent” and should be connected to suitable tubing

and properly vented. Vent gas may be passed through a trap to collect hazardous components as

necessary.

Purge gas can be pumped through cell and flow path tubing and through the electrolyte in

the tank for active de-aeration. See the FlowCell software manual for how to operate the 857 unit

for active purging of the reactants with the purge gas.

Table 1. Rotometer flow rate vs. scale reading.

Scale Reading Flow Rate (mL/min)

65 522 60 483 55 446 50 403 45 365 40 322 35 279 30 239 25 196 20 156 15 119 10 86 5 60

4.5. Potentiostat

A method of extracting and dissipating electrical power from the cell under test during

discharging is needed. Typically this is a resistive device that will cause current to flow when

connected to the terminals of the flow cell. A method of delivering electrical power to the cell

under test during charging is also needed. A high-current potentiostat is used to accomplish both

charging and discharging. The potentiostat consists of a power amplifier, voltage and current

measurement circuits, and control and data acquisition electronics. Most potentiostats, including

that of the 857, are microprocessor-controlled and interface with a host computer. The


21

potentiostat must have maximum current (amperes), voltage (volts), and power (watts) ratings

adequate for the flow cell to be tested.

4.6. Data Acquisition

A data acquisition system is needed to measure all of the desired operating parameters of

the flow cell under test and present this data in graphic and numerical form for the user. The use

of a PC permits the flow cell parameters to be monitored, controlled, and stored for later

analysis.

Typical operating parameters that may be measured and/or calculated are whole cell

voltage, half cell voltage (if an internal reference electrode is available), iR-corrected potentials

can cell internal (ohmic) resistance, cell current, cell power, reactant flow rate and temperature,

and cell temperature.

The 857 test system also includes provisions for electrochemical state-of-charge

measurement. The 857 cell cable includes dedicated voltage sense leads that can be used with an

electrically-isolated monitoring cell that is exposed to the same electrolytes that the operating

flow cell is subjected to. The open circuit voltage of the monitoring cell can be used as a measure

of the state-of-charge with a suitable user-generated calibration curve (e.g., SOC vs. OCV for the

system under investigation). The SOC-OCV calibration curve is specific to the chemistry and

conditions of interest (concentration of reactants and supporting electrolyte species, pH, and

temperature).

4.7. System Software

The FlowCell test system software for controlling the test system and all of its

components is required for the PC as well as an interface to the various parts of the test system.

This will provide the focal point for experiment definition and setup, experiment control, flow

cell monitoring for safe operation, data logging, data display and graphing test results.

The operating software should have provisions for controlling all of the operating

conditions of the flow cell, menus to input the characteristic parameters for the cell, (e.g., cell

active area), operating temperature, reactant flow rate, etc. Provisions should be made for safety

shutdown of the flow cell and test termination, if maximum and/or minimum cell ratings are

exceeded, such as maximum current, power or temperature, minimum cell potential, loss of fuel

supply, electrical power, etc.

See Chapter 9 for a description of FlowCell software.


22

Figure 6 – 857 Flow Diagram.

N2

+-

T

NEGATIVE SIDE POSITIVE SIDE

Cell

T Thermocouple

Heater

Pump

Check Valve

PURGE

P

To Vent

3-way valve

Lower

Valve

Upper

Valve

P

Negative

Electrolyte

Tank

P

To Vent

Lower

Valve

Upper

Valve

Positive

Electrolyte

Tank

T

Rotometer

Flow in 1 direction only

Flow direction depends

on pump direction

MODEL 857 FLOW DIAGRAM

Pressure

regulator

45-70 PSI

Chapter 5 Getting Started & Operation

23

CHAPTER 5 - GETTING STARTED & OPERATION

Chapter 5 deals with initial start up of the 857 Redox Cell Test System and the FlowCell

software. This includes application of the flow cell electrolytes, electrical and mechanical

connections to the flow cell test fixture (cell electrodes or current collectors, electrolyte feed and

return lines), applying AC power to the test system hardware and starting the FlowCell program

to control the test system and collect data.

5.1. Preparation of Reactant, Gas and Electrical Connections

Locate the system test equipment, the 857 Redox Cell Test System and the PC used to

control and monitor the flow cell tests, in a suitable lab environment. The user is responsible for

determining and implementing all safety requirements. Refer to the READ ME FIRST – Model

857 Installation Procedure document in this manual and attached to the 857 to connect the

purge gas supply, AC power, and USB communications cable to the equipment. See CHAPTER

8 - for details on using Swagelok fittings.

When the user has connected the appropriate fuel and purge gas sources to the test system

gas inputs, ALL fuel gas regulators, fittings, connections, gas tubing, and valves should be leak

tested for safety. User must provide for adequate ventilation of fuel gasses exiting the flow cell.

DO NOT place or operate the 857 Controller or 892e Data Expansion Module in a

fume hood.

The 857 Flow Bench passes a comprehensive leak down check before it leaves the

factory. The installer is responsible for checking all user connected fittings, hoses, tubing,

and other connections.

Observe all safety precautions associated with the electrolytes and gases in use.

When in doubt, consult the material supplier’s material safety data sheets (MSDS).

At this time, the purge gas tank valve (normally N2) and its regulator should be opened to

verify that the purge flow is present.

5.2. Check List Before Proceeding: 1. Inspect all purge gas connections

2. Leak check purge gas connections

3. Examine all cable connections between the test equipment and the flow cell

4. Install FlowCell software but do not start it at this time.

5.3. Apply AC Power

Connect the 857 power cord to a power outlet. If the available line voltage is not 120

volts, 50-60 Hz, and the 857 is not built with the 220 V option, see section 3.5 on using a step-

down transformer.

Chapter 5 Getting Started & Operation

24

Apply AC line power to the Model 857 by placing the ‘POWER’ switch in the ‘ON’

position. The cooling fan in the 857 should start and the front panel display and temperature

controllers should illuminate. The temperature controllers should display, “SELF TEST” for

several seconds and then revert to their default set points. The default set point is 15 °C for all

three temperature controllers.

A note about the temperature controllers: DO NOT use the front panel controls on the

temperature controllers to adjust the temperature set points! The set point values should

ALWAYS be entered from the FlowCell software menus. If the controllers display other than 15

°C set point (green display) when 857 power is applied (before starting the FlowCell software),

reset them to 15 °C.

5.4. Storage and Shipping

Do not ship, store, or position the 857 Controller or 857 Flow Bench on its side or

any other orientation than normal/upright when solution is in either of the tanks.

Remove all solution from tanks and flow path, and thoroughly flush with water before

shipping or preparing for long term storage. Cap all inlet and outlet fittings before storage.

Chapter 6 Detailed Specifications

25

CHAPTER 6 - DETAILED SPECIFICATIONS

The Model 857 Flow Cell Test System is an advanced, fully-integrated flow battery test

system. The system consists of a main electronics unit (857 Controller with potentiostat and

flow controls), liquid handling system (857 Flow Bench), and optional multi-channel data

acquisition module (892e Data Expansion Module).

6.1. Features

Complete electronics for charge, discharge, electrolyte flow control, temperature control,

and data acquisition.

Complete flow path including pumping and storage for anode and cathode electrolytes.

Uses a potentiostat for charge and discharge operation in constant-current or constant-

voltage mode.

Three current range potentiostat for accurate charge and discharge current measurement

EIS and HFR during charge or discharge.

Voltage scanning for CV and LSV experiments.

Sense input for whole-cell measurements including EIS and HFR.

Auxiliary voltage input for half-cell DC and EIS/HFR measurements.

State-of-Charge (SOC) voltage input for real-time reactant SOC measurement.

Integrated constant-voltage, scan voltage, constant-current, and scan current, open circuit,

voltage EIS, and current EIS experiments in software with battery/fuel cell polarity

conventions for automated charge/discharge cycling, testing and diagnostics, data

readable in FCView.

User-defined experiment termination/reversal, e.g., voltage or current limit.

Inputs for anolyte and catholyte state-of-charge electrodes

Safety features: shutdown on E-stop or potentiostat over voltage/current fault

6.2. Specifications

Cell Connections 4-terminal (main and sense leads) plus

differential Auxiliary voltage and SOC

inputs

Charge and Discharge Modes (Potentiostat Control):

Full Scale Current Ranges: ±7 A, ±700 mA, ±70 mA

(nominal, not including over-range)

Current Range Selection: Manual

Resolution: 488 A (7 A range) to 4.88 A (70 mA

range)

Limit of Error: ±1.5% of range

Set and Read Voltage vs WE: > ±3.000 V

Current: ±7000 mA (Short Circuit Protected)

Cell Voltage Sense Leads: Differential with driven shields

Voltage Measurement Resolution: 152 V

Sense Lead Input Resistance: 1.0 GΩ


26

Modes of Operation: Constant or scan current or voltage

Data Acquisition Rate: 10 points/sec

Impedance Measurement:

Internal Impedance Analyzer Type: Single sine, two gain/phase measurement

channels, one generator output channel

Internal Analyzer Frequency Range: 1 mHz to 10 kHz

Measurement Types: Sweep EIS and single-frequency HFR

real-time measurement, whole or Aux

User Controls and Connections:

Front Panel: Cell cable connector (main current and

voltage sense leads, Aux, SOC leads), cell

heater receptacle, cell thermocouple jack,

E-stop button Power and Cell indicators,

Power switch; temperature controllers

(Anode/Negative, Cathode/Positive, Cell)

Rear Panel: AC power in, USB port, thermocouple

jacks (Anode/Negative, Cathode/Positive),

connectors for pump control and

heater/pump power, power and serial

interface for 892e Data Expansion Module

Cell and Electrolyte Handling:

Construction: Nonmetallic flow path components

Pumps: Individual, variable speed (software

controlled)

Flow Rate Range: 1 to 1,000 L/min per pump (max flow rate

may be limited by solution viscosity

and/or flow path hydraulic resistance)

Anolyte & Catholyte Temperature Range: Ambient to 50 oC

Cell Temperature Range: Ambient to 50 oC, heated/cooled with

temperature controller

Negative (Anolyte) and Positive

(Catholyte) Solution Reservoir:

975 mL each; heated with temperature

controllers; N2 blanket and purge; solution

level visible

N2 Purge: Low-pressure N2 supply and vent/purge of

reservoir, tubing and cell

Reservoir Drain: Pumped, manually controlled with valves

Cell and Flow Path Flush: Pumped, manually controlled with valves

Additional Data Acquisition (with Optional 892e Data Expansion Module):

Number of Channels: 16

Type: 8 x Temperature (Type K or T

thermocouple); 8 Voltage (±5 V) or other

Physical and Environment:

Operating Temperature: 5 to 35 oC


27

Operating Humidity 0 to 90% RH, non-condensing

Power Source: 100-120 VAC 50/60 Hz

(220-240V model available)

Dimensions and Weight:

857 Controller

857 Flow Bench

15 cm H x 48 cm W x 66 cm D; 8.2 kg

(6” H x 19” W x 26” D); 18 lb.

66 cm H x 48 cm W x 66 cm D; 24 kg

(26” H x 19” W x 26” D); 52 lb.


28

Chapter 7 Troubleshooting

29

CHAPTER 7 - TROUBLESHOOTING

NOTE: Recommended operating systems are Windows 2000, XP Pro, Vista, and

Windows 7 (32-bit version). Operation from Windows 95, 98, ME or XP Home is not

recommended.

7.1. Communication Problems

See FlowCell Software Manual for more information.

“Could Not Find Instrument” error on startup of FlowCell or SAI857 OLE window pops

up with error messages during operation: Ensure that latest version of FlowCell is installed

on a computer with the one of the above recommended operating systems. Ensure that USB

cable is properly connected from computer to 857. If a USB hub is used, try a direct connection

to see if the hub is the problem. Close and restart FlowCell.

If the problem persists, turn off the 857 and open Windows Device Manager (from Control Panel

or Control Panel > System, menus vary with Windows version). Expand the list of HID/Human

Interface Devices. Turn on the 857, the list should update and add a new “HID Compliant

Device” and “USB Human Interface Device” or “USB Input Device”. “New Hardware Found”

or similar messages should appear. Turn off the 857 and the items added to the list should go

away. Note that these are general text descriptions and vary with Windows version.

If the USB cable and the computer’s USB port are good (works with other USB devices when

the same cable is used), the instrument is properly connecting to the computer and there may be a

problem with proper configuration of FlowCell such as the “flowcell.ini” file. This can be

remedied by renaming “flowcell.ini” and reinstalling the latest version of FlowCell. This will

install the latest software with a new “flowcell.ini” file. The menu settings in this case should be

reviewed since previous user settings will have been erased.

If the above items do not add to the list in Device Manager when the 857 is turned on, there

could be a problem with the 857 hardware. If the problem persists, cut and paste the text of any

errors and email with a problem description to [email protected] for further

assistance.

“Temperatures read -999” Communications with the temperature controllers have been lost.

Allow at least 10 seconds after power up of the Model 857 before starting the FlowCell program

to allow the temperature controllers to initialize. Display of this message can indicate the failure

of one of the temperature controllers. Contact the factory for assistance.

7.2. Hardware Problems

1) There is no power when unit is turned ON; the displays do not light. AC power is

not available to the Model 857.

The fuse on the rear panel of the control unit may be blown. Replace it with a 10A, 3AG

size, time delay type fuse. Determine the cause of the failure before proceeding.

mailto:[email protected]

Chapter 7 Troubleshooting

30

2) The unit alarms when the ‘FLOW ON’ button is pressed in the software.

The ‘EMERGENCY STOP’ switch is activated, or cell voltage, current, or temperature

or tank temperature is outside limits configured in the Setup Cell and Setup Flow menus

as described in the alarm message that appears.

3) The reported cell voltage is incorrect or extremely noisy.

The sense leads (V+ and V-) are reversed or not connected. The sense leads are required

to measure the flow cell voltage and should be connected at the cell independent of the

load current carrying leads. These will measure the actual value at the cell plates. The

instrument will not operate if these are not connected correctly. Connect the “Aux+”,

“Aux-”, “SOC+”, and “SOC-” inputs to the cell with the “V-” sense lead if not used. See

page 13 for more information.

Note: Ensure that the cell is completely electrically isolated (insulated) from earth ground

or metal equipment chassis to prevent measurement errors, noise, and possible equipment

damage. The best way to ensure this is to operate the cell in the 857 Flow Bench’s drip

pan and observe precautions listed in Chapter 3 for cell and cell heater (if used)

construction.

4) Over temperature shut down.

Check for any cooling airflow restrictions. The rated operating temperature of the 857

Controller electronics is 5 to 35oC. Prolonged over temperature operation may damage

the 857 Controller electronics.

Chapter 8 Swagelok Tube Fitting Instructions

31

CHAPTER 8 - SWAGELOK® TUBE FITTING INSTRUCTIONS

This section describes use and installation of Swagelok fittings to attach gas supply lines

he Model 857. Swagelok fittings are used to attach the purge gas line to the 857 Flow Bench.

CAUTION

Do not mix or interchange Swagelok parts with those of other manufacturers. Swagelok

tube fittings are manufactured to exacting tolerances. The critical interaction of precision parts as

designed is essential for reliability and safety. Interchanging and intermixing tube fitting

components of different designs or made by different manufacturers may result in leaks, tube

slippage, and may be dangerous in critical applications.

8.1. Assembly Instructions for Standard Swagelok Metal Tube Fittings

These instructions apply to traditional metal fittings and fittings with the advanced back-

ferrule geometry.

(a) (b) (c )

Figure 7 – Installation of standard Swagelok fitting. Images © 2006 Swagelok Company.

1. Insert tubing into the Swagelok tube fitting – Figure 7(a).

2. Make sure that the tubing rests firmly on the shoulder of the tube fitting body and that the

nut is finger-tight.

3. Scribe the nut at the 6 o’clock position – Figure 7(b).

4. While holding fitting body steady, tighten the nut 1-1/4 turn to the 9 o’clock position -

Figure 7(c).

Note: For 1/16, 1/8, and 3/16 inch and 2, 3, and 4 mm tube fittings, tighten the nut 3/4

turn to the 3 o’clock position.

8.2. Gageability

Chapter 8 Swagelok Tube Fitting Instructions

32

On initial installation, the Swagelok gap inspection gauge assures the installer or

inspector that a fitting has been sufficiently tightened. The inspection gauge is available from

Swagelok.

Position the Swagelok gap inspection gauge next to the gap between the nut and body.

• If the gauge will not enter the gap, the fitting is sufficiently tightened.

• If the gauge will enter the gap, additional tightening is required.

8.3. Reassembly Instructions

Swagelok tube fittings can be disassembled and reassembled many times.

1. Insert tubing with pre-swaged ferrules into the fitting body until the front ferrule seats.

2. Rotate the nut with a wrench to the previously pulled-up position. At this point, a

significant increase in resistance will be encountered.

3. Tighten slightly with a wrench.

Note: Do not use the gap inspection gauge with reassembled fittings.

Chapter 9 FlowCell Software Instructions

33

CHAPTER 9 - FLOWCELL SOFTWARE INSTRUCTIONS

This section provides an overview of the FlowCell software used to operate the 857

Redox Cell Test System.

The FlowCell software installation is for use with ONE 857 Redox Cell Test Station.

9.1. Software Installation

The FlowCell Software CD or USB Memory Stick contains an installation program to

install the necessary software to operate the 857 series Redox Cell Test Systems.

Do not try to directly copy the files onto a hard disk as they are compressed and will not

run. The CALIBRATION disk will be requested by the FLOWCELL installation program if is

required.

The installation program installs all programs to a subdirectory c:\flowcell\.

It also creates a subdirectory for data under the name c:\flowcell\data\.

The installation also creates a Program Group under the name ‘FlowCell’.

The installation creates a FlowCell startup icon on the desktop.

To properly install software on a PC with Windows 2000, XP Pro, VISTA,

or Windows 7 you MUST log on using an account with Administrator rights. If you

do not have administrator rights for the computer, the setup programs will display an error

message and will not install. Consult your computer system administrator for more information

on user account types.

9.1.1. Installing FlowCell Software:

1) Insert the Scribner Associates, Inc. disc into the CD drive or the thumb drive in to

the USB port. If the setup program does not automatically start, run the SETUP

program on the CD.

2) Click once on the FuelCell Button to start the installation. Follow the instructions

in the installation screens.

3) Change the selected drive from the Destination Directory screen if you would

like to install the program to a drive other than C:

4) Select the Model - Power and Current ratings are listed on the back panel of the

857 Controller.

5) Click “Finish” to complete the installation.


34

9.2. Starting the FlowCell Software On completing the installation there should be one new icon on the desktop named

“FlowCell”. Double click on this icon to start the FlowCell software.

When the program is started, an additional monitoring program called SAI 857 OLE

Load Control will be started and remain running to indicate the connection of the FlowCell

software. Do not close the SAI 857 OLE Load Control program while FlowCell is running; it

may be minimized to the Windows taskbar.

9.3. Setup Cell Menu When FlowCell is first started, the Setup Cell menu will appear. The purpose of this

menu is to select the cell operating parameters. The default values in the flowcell.ini file will be

loaded.

There are several physical and

electrical parameters to be defined for

operation of the cell, including surface area

and cell fixture temperature, and maximum

and minimum control and shut-down current

and voltage limits. There is also a check box

for an audible beep (from the PC speaker)

upon a limit condition.

You may change any of the values in

this menu or leave them at their defaults if

they match the cell. All values in this menu

can be altered later under the Setup | Cell...

menu. When you are satisfied with the

values, click OK. If you have changed some

values and then wish to discard them and

accept the defaults, click Cancel.

The Surface Area and Number of

Cells in Stack cannot be modified in the

Change Cell experiment. These values can only be modified through the Background Cell

settings.

The Cell Temperature setpoint controls the heaters in the fuel cell fixture. These are

powered by the connector on the front panel. To provide a safety unit for cell temperature, which

may rise due to iR heating, the system will shut down if the Maximum Temperature value is

exceeded. The Maximum Temperature must not exceed 50 oC.

The next six lines define the maximum and minimum allowable values for Current (I)

and Voltage (E), measured in Amperes (A) and Volts (V), respectively.

The system will not permit operation of the cell at values greater than the Maximum or

less than the Minimum control values set in this menu.


35

If the Shut Down Min Voltage (E) or Shut Down Max Voltage (E) is detected, the

system will enter a safe-mode by turning OFF the potentiostat (load), flows and temperatures.

9.4. Set-up Flow Menu Next the Setup Flow menu will

appear. The purpose of this menu is to select

the electrolyte solution and flow parameters

for the flow cell. The default values in the

flowcell.ini file will be loaded.

There are two basic parameters to be

selected for both the Negative and Positive

Electrolytes: flow rate (mL/min) and tank

temperature.

The system will shut down if the

measured temperature exceeds the Maximum

value.

Values in this menu can be altered later under the Setup | Flow... menu. When you are

satisfied with the values, click OK. If you have changed some values and then wish to discard

them and accept the defaults, click Cancel.

The menu is divided into 2 identical parts, one for the Negative Sided Flow and the other

for the Positive Side Flow.

9.5. Main FlowCell Window When the Setup Cell and Setup Flow selections are complete, the main screen of

FlowCell will open. If it is not already full size, maximize this window by clicking on the

maximize icon in the upper right corner of the FlowCell window. The FlowCell screen is divided

into several sections as shown below.


36

9.5.1. Control Buttons In the top-left corner of the window are three large buttons: Apply Flow, Apply Load

and Apply All Temp. A BLUE button it indicates that the action is not engaged (OFF); a RED

button indicates that the action is engaged (ON). These buttons operate as follows:

Apply Flow - Clicking on this button starts the pumps and flow of the solutions at the

rate specified in the Setup Flow menu. Once the flow is activated, this button becomes red and

displays the message Stop Flow. Clicking on the button will stop the pumps and solution flow,

and turn the button back to its original state. If the load is applied when you click on the Stop

Flow button, the load will be removed.

Apply Load – Clicking on this button turns the potentiostat on and applies the

background load (current or voltage) condition. Note: Prior to activating this control make

certain that the cell is connected to the 857 Controller through the 857 Cell Cable and that the

current and sense leads are properly connected. Failure to do this may result in damage to the

857 Controller or the cell under test.

The potentiostat cannot be enabled unless the flow button has been activated first, and an

error message will result if you attempt to apply the potentiostat without flow enabled. Once the

potentiostat is engaged, the button turns red and displays the message Stop Load. Clicking on

this will disengage the potentiostat from the cell and turn the button back to its original state. The

cell will drift to its open circuit voltage.

Apply All Temp - Clicking this button applies the temperature set-points defined in the

Setup Cell and Setup Fuel menus. Individual temperatures can be applied using the check boxes

to the right of this button. When any temperature is applied, the button turns red and displays the

message Stop All Temp. Clicking on this will apply the Standby Temperature Set-point defined

in the Instrument Configuration screen.

Control Buttons Experiments Opens Flow Selection window

Data Values

Background Graphs


37

9.5.2. Data Values

Below the apply buttons appear four large display meters. The Current and Potential

meters have fixed functions and always display total cell current and total cell voltage. The User

meter may be modified to display any of the measured values.

The right side of the main FlowCell window displays the complete list of measured

values.

Very Important: The check boxes next to each value select the values which will be

saved in data files. If the box is checked, the value will be saved. If the box is not checked, the

value will not be saved. When data acquisition is in progress, the selected values cannot be

changed. Because data files can be very large, it may be important to save only the necessary

values.

9.6. Background FlowCell has two different control modes: Background and Experiments. The

Background mode allows immediate manual control of the cell conditions. Background may be

thought of as a 'steady state' mode, since the cell is in operation at a fixed control point.

Experiments are used to perform a predefined (usually dynamic) sequence of events.

When the system is started, it initially operates in the Background mode. It also reverts to

the Background conditions after an

Experiment sequence has been

completed. If the Background conditions

are changed while an Experiment

sequence in progress, the new

Background conditions will be applied

after the sequence is completed.

Selecting the Cell icon opens the Setup Cell window and is used to define conditions

such as the cell size, potential and current limits, and cell temperature. The Setup Cell screen is

also displayed during program startup. This allows the background conditions to be set before

the system is started.

Selecting the Flow icon opens the Setup Flow window for modification of the flow rates

or tank temperature set points. The Setup Fuel screen is also displayed during program startup.

This allows the background conditions to be set before the system is started.

The Recording icon is used to adjust the data acquisition rate used when the instrument

is operating in the Background mode. The Start icon is used to specify a data file and start

acquisition. While Background data acquisition is in progress, the Record icon can be used to

change measurement rates, the Pause button can be used to temporarily stop acquisition, and the

Stop button ends acquisition. If an Experiment sequence is started, the Background acquisition is

normally halted and resumes after the Experiment sequence finishes. The Record button can be

used to modify this behavior so that the Background data file receives data during Experiments.

The cell may be controlled using constant current or constant voltage Control Modes. The

Control Value may be specified by typing a new value and clicking on Apply, or by moving the

Control Scrollbar. The control range or limits of the scrollbar are defined by the minimum and

maximum limits defined in the Cell setup screen.


38

The Record and Control spinners indicate which functions are active. For example,

when an experiment is being performed, the Background Control spinner will stop and a

Control spinner in the Experiments section of the screen will be displayed indicating that the

load is being controlled by the experiment and not by the background setting.

9.7. Graphs The lower portion of the screen is used to display graphs of the measured data. Any

number of graphs may be displayed at the same time.

New graphs are created using the Graphs Menu. Select the X-axis type, and then select

the Y-axis from the available options. Note: Only the parameters which will be saved in data

files are available as graph axes.

After a graph is created, other configuration options are available by clicking on the

graph using the Right Mouse Button and selecting Setup....

Use the Windows | Tile options to rearrange to the graphs on the display.

Each graph may display either Background Data or Experiment Data. Separate time

values are maintained for each mode.

Background Data: The data is graphed with both red dots and blue lines.

The red dots are displayed every second, independent of the data acquisition rate and

show the last 1,000 seconds of operation. They provide a continuous, live display of the cell

conditions.

Blue lines connect data points that are being saved to the Background data file. Only the

last 10,000 data points are displayed. Other data many be contained in the data file, but not

displayed on the graph. If background data is not being saved, the blue lines will not be

displayed.

The time axis is reset to zero when Background data acquisition is started (using the

Background Start button). Starting and stopping Experiments does not reset the Background time

axis to zero.

The Pause and Continue functions do not reset the time axis.

Experiment Data: The data is graphed with both red dots and blue lines. Both dots and

lines are displayed at the rate specified by the experiment being performed. If no data file is

specified for the experiment, the red dots will be displayed, but not the blue lines.

The time axis is reset to zero when an Experiment sequence is started (using the Run

button). Time is not reset to zero between experiments in a sequence. For example, if two

experiments are run in a sequence, and the first experiment lasts 100 seconds, the data from the

second experiment will start at t = 100, not at t = 0.

Scaling Graphs: Graphs can be rescaled using several different methods.


39

To specify fixed axes limits, Right Click on a graph and select Setup....

To autoscale the graph so that all data points are visible, Right Click on the graph and

select AutoScale.

To autoscale all graphs, use the keyboard shortcut Ctrl+A.

To create a scrolling axis, Right Click on the graph and select AutoScroll. The current

span of the x-axis will be maintained and the axis will scroll to the left as new data is aquired. To

change span of the scrolled x-axis, use Setup... to manually select an axis range and then select

AutoScroll. Alternately, use the Zoom feature described below to select a span of data and then

select AutoScroll.

To Zoom the axis to examine data more closely, click on a graph, hold down the mouse

button and drag the mouse to select an area of data. Data inside the rectangle will be expanded to

fill the graph. After zooming, the axes will be fixed and may not display new data. Use

AutoScale or AutoScroll to resume automatic scaling.

9.8. Flow Select Menu Click on the Flow Select button to open the Flow Selection window.

Operations such as filling and draining the tanks,

purging the cell, and flushing the cell are performed from

within the Flow Selection window. Note that temperatures

and the potentiostat (load) cannot be turned on when in

the Flow Selection mode.

The Flow Selection mode is intended for start-up and shut-down of the flow cell and test

system and for maintenance operations such as transferring the electrolytes to their tanks for

storage, actively purging the cell and solutions with purge gas (e.g., for de-aeration), as well as

draining the cell and flushing it with water prior to disconnecting it from the 857 Flow Bench.

The RIGHT side of the Flow Selection window pertains to actions performed by or on

the right tank and pump of the 857 Flow Bench and is reserved for the Positive Electrolyte.

Likewise, the LEFT side of the Flow Selection window pertains to actions performed by or on

the left tank and pump of the 857 Flow Bench and is reserved for the Negative Electrolyte.

Operations performed on the Negative (left) and Positive (right) electrolytes are

independent.

The direction and speed (flow rate) of the pump is controlled through FlowCell. The

operator should not manually operate the pumps.

It is recommended that low flow rates are used initially until the operator confirms proper

operation of the flow system. Ensure that all connections and flow path elements are in-place,

connected and that the valves are in the correct state (valve position) prior to starting the pumps.

Click “Stop Flow” to stop both pumps.


40

The five (5) flow selection modes are described below.

Note that only when the 857 Flow Bench is in the Operating Mode is the operator

permitted to exit the Flow Selection window.


41

9.8.1. Purge System / Drain Cell - Figure 8

This mode is used to drain the cell of electrolyte, placing the solution in the tank.

Continued use of this mode after draining the cell will cause gas in the tank to be pumped

through the flow loop, cell and tank thus actively purging the flow path and electrolyte.

In this mode the pump operates in the counter-clockwise direction. The upper and lower

valves are positioned as shown in Figure 8.

Note that active purge of the solution in this mode is only effective if the purge gas flow

rate exceeds the pump flow rate and the tank volume has previously been expunged of unwanted

species (such as oxygen). Verify inert gas flow using the rotometers.

Figure 8 – Purge System / Drain Cell mode in the Flow Selection window.


42

9.8.2. Fill Tanks – Figure 9

This mode is used to pump solution into a tank from an external source. To do this,

connect a tube to the lower valve fitting. Place the free-end of that tube into the solution to be

pumped into the tank. Place the valves in the indicated state.

The pumps will operate in the clock-wise direction, drawing solution from the source

vessel, through the flow path and cell and into the tank via the upper valve.

Click Apply to start the pumps.

Figure 9 – Fill Tanks mode in the Flow Selection window.


43

9.8.3. Operate Mode - Figure 10

This mode must be entered before exit of the Flow Selection window is enabled (un-

greyed). Make sure to place the valves in the state indicated before exiting the Flow Selection

window.

To prepare to operate the flow cell, place the valves in the position shown and click

Apply.

The pumps will operate in the clockwise direction drawing solution from the tank,

through the flow path and cell and back into the tank through the upper valve.

Figure 10 – Operate mode in the Flow Selection window.


44

Drain Cell and Tank - Figure 11

Figure 11 This mode is intended for draining of the electrolyte from all components of the

system, including the cell, tank, and flow path.

To do this, connect the upper valve fitting to a collection tank with tube, place the valves

in the position shown, and click Apply.

The pumps will operate in the clockwise direction drawing solution from the tank,

through the flow path and cell and out the upper valve into the collection vessel.

Figure 11 – Drain Cell and Tank mode in the Flow Selection window.


45

9.8.4. Flush Cell and Pump - Figure 12

This mode is intended for flushing of the cell, flow loop and pump tubing with water or

other flushing solution.

To flush the cell and flow path, connect the lower valve fitting to a suitable collection

container. Connect a tube to the upper valve fitting. Place the free end of that tube in a container

of the flushing solution such as deionized water. Place the valves in the position shown and click

Apply.

The pumps will operate in the counter-clockwise direction drawing solution from source

flush solution container and pumping it through the flow path and cell and out the lower valve

into the collection vessel.

Figure 12 – Flush Cell and Pump mode in the Flow Selection window.


46

9.9. Experiments Experiments are used to define a sequence

of control and data acquisition events. A

short description of each experiment in the

sequence is displayed in the experiment

list.

Edit... is used to modify the settings for

the highlighted line in the experiment list.

New... inserts a new experiment into the

list. Note that the new experiment is

inserted before the line that is highlighted.

To add an experiment to the end of the

list, highlight the blank line at the end of

the list.

Delete removes a line from the experiment list.

The Up and Down buttons are used to change the order of the experiments in the experiment list.

Run All starts the experiment sequence. All of the experiments in the list will be performed.

Run Sel begins the experiment sequence. Only the highlighted experiments are performed.

While experiments are in progress, two options are available. Stop will end the experiments and

return the system to the Background mode. Skip will end the current experiment and proceed to

the next experiment in the list.

The following experiment types are available:

Open Circuit Measures the Open Circuit Potential for a specified amount of

time.

Constant Current Applies a Constant Current for a specified amount of time.

Constant Voltage Applies a Constant Potential for a specified amount of time.

Scan Current Sweeps the Applied Current between specified set-points.

Scan Voltage Sweeps the Applied Voltage between specified set-points.

Current Impedance Performs a current-controlled Impedance measurement

Voltage Impedance Performs a voltage-controlled Impedance measurement

Change Cell Changes the Cell parameters such as the cell temperature and

alarm limits.

Change Flow Changes the Flow conditions such as flow rate and tank

temperature

Run External Utility Runs a user-written external program.

Repeat Loop Inserts a loop into the experiment list. Experiments that are placed

within the loop will be repeated a specified number of times.


47

9.9.1. Open Circuit

Measures the Open Circuit voltage for a

specified amount of time.

When the experiment is performed, the data

will be saved in the file specified by Data

File. The Directory button can be used to

display a list of all directories and files. This

is particularly useful, if you forget the file

names you have already used. Before

FlowCell begins performing the first

experiment in the experiment list, you will be

warned, if the file already exists.

FlowCell automatically appends the suffix

‘.FCD’ to data files, if you do not enter one.

Thus, if you specify tutor1, the file tutor1.fcd

will be used. If however, you specify

tutor1.abc, the file tutor1.abc will be used.

The Comments text is saved in the data file.

The time, date, and all measurement parameters displayed in this window are automatically

saved in the data file, so you do not need to write these into the comment lines.

When an experiment is inside a repeat loop, it will be performed multiple times. The data from

each repetition may be saved in a Single File (with multiple data sets in a single file), or it can be

saved in Separate Files. When separate files are used, new file names are automatically

generated to distinguish each repetition. For example, if the file name tutor1.fcd is selected, data

files named tutor1_rp01.fcd, tutor1_rp02.fcd, tutor1_rp03.fcd... will be created.

When an experiment is inside a repeat loop, it is not necessary to save the data from all

repetitions. If 100 repetitions are chosen, and Save Every n’th Cycle is 10, only the data from

cycles 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 will be saved.

Experiment:

Duration determines the total length of the experiment.

Data Acquisition:

If Fixed Rate is chosen, the acquisition rate in seconds/point is specified.

The delta-E method is specified by three parameters. Data is measured by the instrument at the

rate specified by Minimum Time/Point, but not all of this data is saved. If the cell voltage

changes (compared to the last point saved) by more than the V/Point setting, a new data point is

saved. If the signal is not changing, the data is saved at the rate specified by the Maximum

Time/Point. Using this method allows FlowCell to collect large numbers of data points when the

signal is changing quickly and relatively few points when the signal is stable. Before using


48

delta-E, you may wish to use a ‘Fixed Rate’ experiment to get a feel for the noise level of the

cell. This will help in selecting an appropriate value for V/Point.

Termination:

If all Use boxes are unchecked, the experiment will be performed for the time specified by

Duration.

If Use dV/dt is checked, the experiment is automatically terminated before the Duration period

if the rate of drift in the voltage goes below that specified by dV and dt. The data is averaged

over periods of dt. If the average voltage changes by less that dV over two successive periods of

dt, the experiment is terminated. Note that a slope of 6 mV/minute can be specified several ways.

If dV = 0.1 mV and dt = 1 second, the termination will not be performed correctly. The noise

level of the instrument is larger than 0.1 mV and will interfere with the termination. Only when

data is averaged over a long period of time can a slope termination be used.

If Use V < is checked, the experiment is automatically terminated before the Duration period, if

the whole cell voltage goes below the specified value. If Use V > is checked, the experiment is

automatically terminated before the Duration period, if the whole cell voltage goes above the

specified value. The termination voltages are tested for each saved data point, as specified by the

data acquisition rate.

FlowCell displays a one-line description of each experiment in the experiment list. If a

Description is entered, it will be used in the list. If no description is entered, FlowCell will

create a description from the experimental parameters.

If AutoPrint Graphs is selected, after the experiment is finished, any graphs that are displaying

experiment data will be printed.

The OK button exits the setup window and saves any changes you may have made.

Cancel exits the setup window. Any changes you may have made to the parameters are lost.

Help accesses the on-line help information on the setting up of this experiment.


49

9.9.2. Constant Current

Applies a constant current for a specified

amount of time.
















The time, date, and all measurement

parameters displayed in this window are

automatically saved in the data file, so you do

not need to write these into the comment

lines.









Experiment:

The Applied Current is the total current applied to the cell. If Absolute is used, the entered

current will be applied. If vs. Previous is used, the current is changed relative to the current just

prior to the experiment. For example, if the previous experiment was ‘Controlled Voltage’, and

at the end of this experiment the current was 1.5 Amps, selecting 0 vs. Previous would change

the unit to ‘Controlled Current’, but the current would stay at 1.5 Amps.


Data Acquisition:

If Fixed Rate is chosen, the acquisition rate in seconds/point is specified.


50

The delta-E method is specified by three parameters. Data is measured by the instrument at the

rate specified by Minimum Time/Point, but not all of this data is saved. If the cell voltage

changes (compared to the last point saved) by more than the V/Point setting, a new data point is

saved. If the signal is not changing, the data is saved at the rate specified by the Maximum


signal is changing quickly, and relatively few points when the signal is stable. Before using

delta-E, you may wish to use a ‘Fixed Rate’ experiment to get a feel for the noise level of the

cell. This will help in selecting an appropriate value for V/Point.

Termination:

If all Use boxes are unchecked, the experiment will be performed for the time specified by

Duration.

If Use V < is checked, the experiment is automatically terminated before the Duration period, if


automatically terminated before the Duration period, if the whole cell voltage goes above the



I Range can be used to change the current range used during the experiment step. The default

setting is No Change, which will leave the current range at its existing setting (typically selected

in the Background settings).

The Bandwidth selection can be used to control the speed and frequency response of the

potentiostat. The default setting is No Change, which will leave the bandwidth at its existing

setting (typically selected in the Background settings).










51

9.9.3. Constant Voltage

Applies a constant voltage for a specified

amount of time.


















automatically saved in the data file, so you do

not need to write these into the comment

lines.









Experiment: The Applied Potential is total voltage applied to the entire stack. If Absolute is used, the

entered potential will be applied. If vs. Open Circuit is chosen, the specified potential is added

to the open circuit potential of the cell. For example, -0.1 vs. Open Circuit would apply a

potential 0.1 Volts below the measured open circuit potential. Note that the OCP is sampled

whenever the system is at open circuit. If a load has been applied to the cell, the old OCP may

not reflect new cell conditions. The Open Circuit experiment may be used to update the value

used when calculating vs. Open Circuit potentials.

If vs. Previous is used, the potential is changed relative to the potential just prior to the


52

experiment. For example, if the previous experiment was ‘Controlled Current’ and at the end of

this experiment, the current was 0.65 Volts, selecting 0 vs. Previous would change the unit to

‘Controlled Potential’, but the potential would stay at 0.65 Volts.

The Control parameter selects which voltage is controlled. When E is selected, the total cell

voltage is controlled. When E Compensated is selected, the iR corrected voltage is controlled.


Data Acquisition: If Fixed Rate is chosen, the acquisition rate in seconds/point is specified.

The delta-I method is specified by three parameters. Data is measured by the instrument at the

rate specified by Minimum Time/Point, but not all of this data is saved. If the cell current

changes (compared to the last point saved) by more than the mV/Point setting, a new data point

is saved. If the signal is not changing, the data is saved at the rate specified by the Maximum


signal is changing quickly, and relatively few points when the signal is stable. Before using

delta-I, you may wish to use a ‘Fixed Rate’ experiment to get a feel for the noise level of the

cell. This will help in selecting an appropriate value for A/Point.

Termination: If all Use boxes are unchecked, the experiment will be performed for the time specified by

Duration.

If Use V < is checked, the experiment is automatically terminated before the Duration period if


automatically terminated before the Duration period if the whole cell voltage goes above the














The OK button exits the setup window and saves any changes you may have made. Cancel exits

the setup window. Any changes you may have made to the parameters are lost. Help accesses the

on-line help information on the setting up of this experiment.


53

9.9.4. Scan Current

Sweeps the applied current between

specified setpoints.








experiment in the experiment list, you will

be warned, if the file already exists.









automatically saved in the data file, so you

do not need to write these into the comment

lines.

When an experiment is inside a repeat loop,

it will be performed multiple times. The data from each repetition may be saved in a Single File

(with multiple data sets in a single file), or it can be saved in Separate Files. When separate files

are used, new file names are automatically generated to distinguish each repetition. For example,

if the file name tutor1.fcd is selected, data files named tutor1_rp01.fcd, tutor1_rp02.fcd,

tutor1_rp03.fcd... will be created.




Experiment: Up to 4 separate currents can be applied during the experiment. The experiment starts at the

Initial Current, sweeps to Vertex #1, to Vertex #2, and then to the Final Current. Click on the

Used boxes to turn on and off the Vertex #1 and Vertex #2 setpoints. If a vertex’s Used box is

not checked, that segment of the sweep will be skipped. For example, if only Vertex #1 is

checked the sweep Initial --> Vertex #1 --> Final is performed. If neither vertex is checked,

Initial --> Final is performed.

If Absolute is used, the entered current will be applied. If vs. Previous is used, the current is

changed relative to the current just prior to the experiment. For example, if the previous


54

experiment was ‘Controlled Voltage’ and at the end of this experiment, the current was 1.5

Amps, selecting 0 vs. Previous would change the unit to ‘Controlled Current’, but the current

would stay at 1.5 Amps. If vs. Initial is used, the current is in reference to the Initial setpoint of

this experiment.

A Linear Sweep, Linear Stair-Step or Logarithmic Stair-Step can be performed.

If a Linear Sweep is used, the current will be swept in a smooth ramp, defined by Scan Rate

(mA/second). The Data Rate can be specified as a Fixed Rate (Seconds/Point), or as delta-I

(mA/point).

A Linear Stair-Step scan will step the current

between discrete levels, and hold the current at

value for the specified Step Time.

A Logarithmic Stair-Step scan will step the

current between discrete levels, and hold the

current at value for the specified Step Time. The

current is incremented in logarithmic steps, where the specified number of steps are performed

for each decade of current (factor of 10 of current).

For Stair-Step scans, the Data Rate is specified as either a Fixed Rate (Seconds/Point), or as a

number of Points/Step. If Point/Step =1, the Average % value determines when the data point is

measured during the step. If Averaging=10%, the data point is the average signal during the final

10% of the time at each current step.







Termination/Reversal: Select Reverse Scan, if you want to scan from small currents to larger currents, and then reverse

when the potential drops below the Potential < value or above the Potential > value. When the

reverse scan is triggered, the scan proceeds to the Final Current.

Select Terminate Scan, if you want to scan from small currents to larger currents, and terminate

the scan when the potential drops below the Potential < value or above the Potential > value.







55





56

9.9.5. Scan Voltage

Sweeps the applied voltage between

specified setpoints.








experiment in the experiment list, you will

be warned, if the file already exists.









automatically saved in the data file, so you

do not need to write these into the comment

lines.









Experiment: Up to 4 separate potentials can be applied during the experiment. The experiment starts at the

Initial Potential, sweeps to Vertex #1, to Vertex #2, and then to the Final Potential. Click on

the Used boxes to turn on and off the Vertex #1 and Vertex #2 setpoints. If a vertex’s Used box

is not checked, that segment of the sweep will be skipped. For example, if only Vertex #1 is

checked the sweep Initial --> Vertex #1 --> Final is performed. If neither vertex is checked,

Initial --> Final is performed.

If Absolute is used, the entered potential will be applied. If vs. Open Circuit is chosen, the

specified potential is added to the open circuit potential of the cell. For example -0.1 vs. Open

Circuit would apply a potential 0.1 Volts below the measured open circuit potential. Note that

the OCP is sampled whenever the system is at open circuit. If a load has been applied to the cell,


57

the old OCP may not reflect new cell conditions. The Open Circuit experiment may be used to

update the value used when calculation vs. Open Circuit potentials.

If vs. Previous is used, the potential is changed relative to the potential just prior to the

experiment. For example, if the previous experiment was ‘Controlled Current’ and at the end of

this experiment, the current was 0.65 Volts, selecting 0 vs. Previous would change the unit to

‘Controlled Potential’, but the potential would stay at 0.65 Volts.

If vs. Initial is used, the potential is in reference to the Initial setpoint of this experiment.

Scan Type:

A Linear Sweep or Linear Stair-Step can be performed.

If a Linear Sweep is used, the voltage will be swept in a smooth ramp, defined by Scan Rate

(mV/second). The Data Rate can be specified as a Fixed Rate (Seconds/Point), or as delta-E

(mV/point).

A Linear Stair-Step scan will step the voltage between discrete levels, and hold the voltage at

value for the specified Step Time.

For Stair-Step scans, the Data Rate is specified as either a Fixed Rate (Seconds/Point), or as a

number of Points/Step. If Point/Step =1, the

Average % value determines when the data point

is measured during the step. If Averaging=10%,

the data point is the average signal during the final

10% of the time at each voltage step.

I Range can be used to change the current range

used during the experiment step. The default setting is No Change, which will leave the current

range at its existing setting (typically selected in the Background settings).




Termination/Reversal: Select Reverse Scan if you want to scan from high voltage to low voltage, and then reverse

when the current goes above the Current > value or below the Current < value. When the

reverse scan is triggered, the scan proceeds to the Final Potential.

Select Terminate Scan, if you want to scan from large voltage to low voltage and terminate the

scan when the current goes above the Current > value or below the Current < value

.







58





59

9.9.6. Controlled Current Impedance

Performs an Impedance Sweep using

controlled current conditions.

NOTE: Normal operation of the control

system will be suspended during impedance

measurements. For example, the HFR (High

Frequency Resistance) function used to

measure iR drop in the cell must be

suspended during an impedance sweep

measurement.












Thus, if you specify tutor1, the file tutor1.fcd will be used. If however, you specify tutor1.abc,

the file tutor1.abc will be used.

The Comments text is saved in the data file. The time, date, and all measurement parameters

displayed in this window are automatically saved in the data file, so you do not need to write

these into the comment lines.









Experiment: Note: The DC cell conditions must be stabilized before performing impedance measurements.

Insert other experiment types into the experiment prior to the impedance experiment to select the

steady state cell conditions. The ‘Impedance’ experiment will maintain the DC conditions

applied by the previous experiment.

The AC Amplitude may be specified in Amps, or as a percentage of existing DC current. If the

amplitude is too large, the impedance data may be distorted because of the non-linear E vs. I


60

behavior of the cell. If the amplitude is too small, the impedance data may be noisy. When a

large DC current is present, an AC Amplitude of 10% of the DC current is appropriate. At low or

zero DC current, an AC current that produces ~10mV of AC voltage is suggested. The low

frequency cell resistance can be used to calculate the relationship between AC current and AC

voltage.

A frequency sweep can be performed using Linear or Logarithmic spacing between the

frequencies, or a List of frequencies can be manually selected.

For most impedance experiments, a Logarithmic Sweep, using 10 Steps/Decade is best. This

will produce 10 data points between 1000 Hz and 100 Hz, 10 points between 100 Hz and 10 Hz,

etc.

The Initial Frequency is normally the highest frequency measured, and the Final Frequency is

the lowest.

The Frequency List allows exact frequencies to be selected.

Termination: If Use V < is checked, the experiment is automatically

terminated before finishing the frequency sweep if the

whole cell voltage goes below the specified value. If

Use V > is checked, the experiment is automatically

terminated if the whole cell voltage goes above the

specified value. The termination voltages are tested for each saved data point.
















61

9.9.7. Controlled Voltage Impedance

Performs an Impedance Sweep using

controlled voltage conditions.

NOTE: Normal operation of the control

system will be suspended during impedance

measurements. For example, the HFR (High

Frequency Resistance) function used to

measure iR drop in the cell must be

suspended during an impedance sweep

measurement.












Thus, if you specify tutor1, the file tutor1.fcd will be used. If however, you specify tutor1.abc,

the file tutor1.abc will be used.

The Comments text is saved in the data file. The time, date, and all measurement parameters

displayed in this window are automatically saved in the data file, so you do not need to write

these into the comment lines.









Experiment: Note: The DC cell conditions must be stabilized before performing impedance measurements.

Insert other experiment types into the experiment prior to the impedance experiment to select the

steady state cell conditions. The ‘Impedance’ experiment will maintain the DC conditions

applied by the previous experiment.

The AC Amplitude is specified in mV.


62

A frequency sweep can be performed using Linear or Logarithmic spacing between the

frequencies, or a List of frequencies can be manually selected.

For most impedance experiments, a Logarithmic Sweep, using 10 Steps/Decade is best. This

will produce 10 data points between 1000 Hz and 100 Hz, 10 points between 100 Hz and 10 Hz,

etc.

The Initial Frequency is normally the highest frequency measured, and the Final Frequency is

the lowest.

The Frequency List allows exact frequencies to be

selected.

Termination: If all Use boxes are unchecked, the experiment will be

performed for the time specified by Duration.

If Use I < is checked, the frequency sweep is automatically terminated if the current goes below

the specified value. If Use I > is checked, the experiment is automatically terminated if the

current goes above the specified value. The termination currents are tested for each saved data

point, as specified by the data acquisition rate.
















63

9.9.8. Change Cell

Changes the cell definition parameters. The cell

parameters include the cell temperature and

alarm limits.

The Surface Area and Number of Cells in

Stack cannot be modified in the Change Cell

experiment. These values can only be modified

through the Background Cell settings.

The Cell Temperature setpoint controls the

heaters in the cell fixture. These are powered by

the connector on the front panel. To provide a

safety unit for cell temperature, which may rise

due to iR heating, the system will shut down if

the Maximum Temperature value is

exceeded. The Maximum Temperature must

not exceed 50 oC.

The next six lines define the maximum and

minimum allowable values for Current (I) and

Voltage (E), measured in Amperes (A) and Volts (V), respectively.

The system will not permit operation of the cell at values greater than the Maximum or less than

the Minimum control values set in this menu.

If the Shut Down Min Voltage (E) or Shut Down Max Voltage (E) is detected, the system will

enter a safe-mode by turning OFF the potentiostat (load), flows and temperatures.

If the Beep box is checked, FlowCell will produce a beep from the computers speaker if the

minimum or maximum limits are exceeded.


64

9.9.9. Change Flow

Changes the pump flow and tank heaters.

There are two basic parameters to be selected

for both the Negative and Positive

Electrolytes: flow rate (mL/min) and tank

temperature.

The system will shut down if the measured

temperature exceeds the Maximum value.


65

9.9.10. Run External Utility

Runs a user-written external program.

This experiment does not perform any

measurements. It is used to launch external

utility programs written by the user. For

example, if the user wrote a small program in

Visual Basic to set the temperature on a

temperature controller, this experiment could

be used to run the program to change a valve

not directly controlled by FlowCell.

Program Name should the path and filename

of the user-written program to be run. The Directory button may be used to see your drives and

directories and will help locate the desired program file.

The Command Line Options is text that will be given to the utility program. FlowCell does not

interpret the command line information in any way, but simply passes it on to the utility. The

utility can be written to interpret the command line information. For example, a utility program

to set the temperature on a temperature controller could interpret the command line: 50 10 to

mean that it should set the temperature to 50 °C and wait for 10 minutes before exiting (to let the

temperature stabilize).

If Wait for External Utility to Exit is selected, FlowCell will wait for the utility to close before

proceeding to next experiment in the list.


66

9.9.11. Repeat Loop

Inserts a loop into the experiment list.

Experiments that are placed within the loop

will be repeated a specified number of times.

This experiment puts a pair of Repeat

(Begin) and Repeat (End) lines into the experiment list. Any experiments that are positioned

between the Begin and End will be repeated the specified number of times.

In this experiment list, ‘Constant Current’ and ‘Scan Voltage’

experiments are positioned between the Repeat (Begin) and

Repeat (End) lines. When run, the sequence would be repeated

10 times.

Chapter 10 FlowCell Data and File Formats

67

CHAPTER 10 - FLOWCELL DATA AND FILE FORMATS

10.1. Data Value Definitions

The following list describes the source of each type of data value. Some values are

directly measured and others are calculated from other measured values.

Current

Amps: Measured total current

mA/cm2: Amps × 1000 ÷ Surface Area per Cell

Power

Watts: Amps × Stack Voltage

Watts/cm2: Watts ÷ Surface Area per Cell ÷ Number of Cells in Stack

Potential (Volts)

Stack: Measured Full Stack Voltage

Cell Avg.: Stack ÷ Number of Cells in Stack

Ref1: Measured between Aux. Reference Inputs

iR Comp. Potential (Volts)

Stack: Stack Potential + (Current × HFR)

Cell Avg.: iR Compensated Stack ÷ Number of Cells in Stack

Ref1: Ref1 Potential + (Current × HFR)

iR Drop (Volts)

Stack: Current × HFR

Cell Avg.: Stack iR Drop ÷ Number of Cells in Stack

Ref1: Current + HFR

Cell

Temp (°C): Measured Cell Temperature

SOC (V): Voltage from State of Charge electrodes

SOC (%): Calculated State of Charge

Negative Side

Temp (°C): Measured Negative Side Temperature

Flow (l/min): Flow signal from Negative Side Pump Controller

Positive Side

Temp (°C): Measured Negative Side Temperature

Flow (l/min): Flow signal from Positive Side Pump Controller

Impedance


68

HFR (mΩ): Most recently measured high-frequency resistance. This value is not

scaled by the cell stack number or surface area. It is only available with

test systems containing an internal 880 Frequency Analyzer.

Freq: Applied AC Frequency

Real (Ω): Total measured Real impedance (Z’). The value is not scaled by the cell

stack number or surface area.

Imag (Ω): Total measured Imaginary impedance (Z”). The value is not scaled by the

cell stack number or surface area.

Mag (Ω): Total measured impedance magnitude (|Z|). The value is not scaled by the

cell stack number or surface area.

Angle (Deg): Measured Phase Angle.

Control Signals Note: The control signals record the set-points for each control condition,

not measured values.

Control Status: 0 = flow off, load off; 1 = flow on, load off, 3 = flow on, load on

Ctrl Mode: 0 = Open Circuit; 1=Ctrl Current; 2 = Ctrl Voltage

Ctrl Value: Control Setpoint in Amps, Volts

Cell Temp: Cell Temperature Setpoint

Neg. Temp: Negative side Temperature Setpoint

Pos. Temp: Positive side Temperature Setpoint

Neg. Flow: Negative side Flow Rate setpoint (negative values indicate

counterclockwise flow)

Pos. Flow: Positive side Flow Rate setpoint (negative values indicate

counterclockwise flow)

10.2. Data File Format

The right edge of FlowCell displays the complete list of measured

values.

Very Important: The check boxes next to each value select the values

which will be saved in data files. If the box is checked, the value will be

saved. If the box is not checked, the value will not be saved. When data

acquisition is in progress, the selected values cannot be changed.

Because data files can be very large, it is important to save only the

values which are necessary.

The UP button to the left of the list will compress the list so that only

the saved values are displayed. A compressed list may be expanded

using the DOWN button. The SIZE button will expand the list to use

the full height of the FlowCell window.

An example data file is shown on the following page.

The Header text lists the parameters of the experiment used to measure

the data. The length of the header will vary depending on the

experiment, but the final line of the header will always be “End Comments”.


69

All data values are separated by tabs.

Use With Spreadsheets

When you save data from an experiment, FlowCell stores your data in a format that is

compatible with most spreadsheet software (for example, Microsoft Excel). If you open a data

file in Excel, a Text-Import Wizard starts that attempts to read the data and understand its

format. In this Text-Import Wizard, select Delimited for the file format, and click Finish. You

can also open any data file as a text file in a word processor or other spreadsheet program.

FLOWCELL DATA

FlowCell: Version 1.0

Time: Friday, February 02, 2002 9:20:33 AM

DateTime: 36924.3892713889

This text was entered into the comments section of and experiment

Begin Experiment: Scan C: 0 A; 1 A; 0 vs Initial; 10 Sec/Pt; 0.05 A/Pt

Exp Name

Data File: C:\FlowCell\example data.fcd

Data Append: 0

Comment Lines: 1

Data Comment #1: This text was entered into the comments section of and experiment

Save N: 1

Save Multiple: 0

AutoPrint: 0

Duration: 10

Duration Type: 0

Pol1: 0

Pol2: 1

Pol3: 0

Pol4: 0

Pol1 Type: 0

Pol2 Type: 0

Pol3 Type: 2

Pol4 Type: 2

Pol2 Use: 1

Pol3 Use: 0

Scan Type: 0

Pol Delta Linear: 0.05

Pol Delta Log: 5

Slope Delta Pol: 0.005

Slope Delta Time: 10

Slope Delta Use: 0

Terminate Type: 0

Terminate Pol: 0.3

End Experiment: Scan C: 0 A; 1 A; 0 vs Initial; 10 Sec/Pt; 0.05 A/Pt

DataColumnCount: 11

DataColumn1: 0

DataColumn2: 1

DataColumn3: 5

DataColumn4: 11

DataColumn5: 12

DataColumn6: 41

DataColumn7: 51

DataColumn8: 52

DataColumn9: 53

DataColumn10: 61

DataColumn11: 62

Time (Sec) I (A) Power (Watts) E_Stack (V) E_Avg (V) E_iR_Stack (mOhm) Temp_Cell (C) Temp_Neg (C) Temp_Pos (C)

Flow_Neg (l/min) Flow_Neg (l/min)

End Comments

10.15 0.0000E+00 0.0000E+00 6.4220E+00 6.4220E-01 0.0000E+00 1.7500E+01 1.5300E+01 1.6500E+01 1.9903E-02 1.9666E-02

20.15 5.0026E-02 3.1418E-01 6.2804E+00 6.2804E-01 0.0000E+00 1.7600E+01 1.5300E+01 1.6500E+01 1.9907E-02 1.9676E-02

30.05 1.0001E-01 6.1869E-01 6.1865E+00 6.1865E-01 0.0000E+00 1.7700E+01 1.5300E+01 1.6600E+01 1.9910E-02 1.9673E-02

40.05 1.5003E-01 9.1421E-01 6.0934E+00 6.0934E-01 0.0000E+00 1.7700E+01 1.5400E+01 1.6600E+01 1.9910E-02 1.9693E-02

50.05 2.0000E-01 1.2000E+00 6.0000E+00 6.0000E-01 0.0000E+00 1.7800E+01 1.5400E+01 1.6700E+01 1.9911E-02 1.9693E-02

60.05 2.4997E-01 1.4766E+00 5.9070E+00 5.9070E-01 0.0000E+00 1.7900E+01 1.5400E+01 1.6700E+01 1.9913E-02 1.9691E-02

70.05 2.9998E-01 1.7440E+00 5.8137E+00 5.8137E-01 0.0000E+00 1.8000E+01 1.5400E+01 1.6700E+01 1.9916E-02 1.9698E-02

80.05 3.5004E-01 2.0023E+00 5.7202E+00 5.7202E-01 0.0000E+00 1.8000E+01 1.5500E+01 1.6800E+01 1.9913E-02 1.9691E-02

90.05 4.0000E-01 2.2508E+00 5.6270E+00 5.6270E-01 0.0000E+00 1.8000E+01 1.5500E+01 1.6900E+01 1.9918E-02 1.9710E-02

100.15 4.4999E-01 2.4903E+00 5.5342E+00 5.5342E-01 0.0000E+00 1.8100E+01 1.5600E+01 1.7000E+01 1.9915E-02 1.9705E-02

110.15 5.0000E-01 2.7202E+00 5.4403E+00 5.4403E-01 8.9623E+02 1.8200E+01 1.5800E+01 1.7000E+01 1.9920E-02 1.9700E-02

120.05 5.4996E-01 2.9409E+00 5.3474E+00 5.3474E-01 2.1296E+03 1.8200E+01 1.5800E+01 1.7000E+01 1.9920E-02 1.9695E-02

130.05 5.9999E-01 3.1523E+00 5.2539E+00 5.2539E-01 2.1143E+03 1.8300E+01 1.5900E+01 1.7100E+01 1.9922E-02 1.9713E-02

140.05 6.5000E-01 3.3541E+00 5.1602E+00 5.1602E-01 2.1067E+03 1.8400E+01 1.6000E+01 1.7200E+01 1.9929E-02 1.9717E-02

150.05 6.9999E-01 3.5466E+00 5.0666E+00 5.0666E-01 2.1013E+03 1.8400E+01 1.5900E+01 1.7200E+01 1.9936E-02 1.9717E-02

160.05 7.5000E-01 3.7298E+00 4.9731E+00 4.9731E-01 2.0904E+03 1.8400E+01 1.5900E+01 1.7200E+01 1.9929E-02 1.9725E-02

170.05 8.0000E-01 3.9035E+00 4.8793E+00 4.8793E-01 2.0849E+03 1.8400E+01 1.6000E+01 1.7200E+01 1.9919E-02 1.9727E-02

180.05 8.4997E-01 4.0672E+00 4.7851E+00 4.7851E-01 2.0776E+03 1.8500E+01 1.6000E+01 1.7200E+01 1.9937E-02 1.9730E-02

190.15 9.0002E-01 4.2221E+00 4.6912E+00 4.6912E-01 2.0709E+03 1.8600E+01 1.5900E+01 1.7200E+01 1.9936E-02 1.9730E-02

200.15 9.5000E-01 4.3670E+00 4.5969E+00 4.5969E-01 1.9818E+03 1.8600E+01 1.5900E+01 1.7200E+01 1.9937E-02 1.9725E-02

210.05 1.0000E+00 4.5027E+00 4.5025E+00 4.5025E-01 1.9792E+03 1.8600E+01 1.6000E+01 1.7200E+01 1.9931E-02 1.9756E-02

220.05 9.4996E-01 4.3657E+00 4.5957E+00 4.5957E-01 1.9839E+03 1.8700E+01 1.6000E+01 1.7200E+01 1.9936E-02 1.9744E-02

230.05 9.0002E-01 4.2200E+00 4.6888E+00 4.6888E-01 2.0740E+03 1.8800E+01 1.6000E+01 1.7300E+01 1.9940E-02 1.9737E-02

240.05 8.4996E-01 4.0649E+00 4.7824E+00 4.7824E-01 2.0808E+03 1.8800E+01 1.6100E+01 1.7300E+01 1.9944E-02 1.9725E-02

250.15 7.9999E-01 3.9004E+00 4.8755E+00 4.8755E-01 2.0901E+03 1.8800E+01 1.6100E+01 1.7300E+01 1.9931E-02 1.9744E-02

260.15 7.4999E-01 3.7268E+00 4.9691E+00 4.9691E-01 2.0991E+03 1.8800E+01 1.6100E+01 1.7300E+01 1.9937E-02 1.9732E-02

270.05 7.0000E-01 3.5435E+00 5.0622E+00 5.0622E-01 2.1066E+03 1.8900E+01 1.6200E+01 1.7400E+01 1.9936E-02 1.9732E-02


70

280.05 6.4999E-01 3.3512E+00 5.1557E+00 5.1557E-01 2.1166E+03 1.8900E+01 1.6200E+01 1.7400E+01 1.9942E-02 1.9742E-02

290.05 6.0002E-01 3.1497E+00 5.2494E+00 5.2494E-01 2.1255E+03 1.8900E+01 1.6200E+01 1.7400E+01 1.9952E-02 1.9761E-02

300.05 5.5002E-01 2.9386E+00 5.3427E+00 5.3427E-01 2.1356E+03 1.9000E+01 1.6200E+01 1.7400E+01 1.9953E-02 1.9761E-02

310.25 4.9998E-01 2.7180E+00 5.4362E+00 5.4362E-01 8.5970E+02 1.9100E+01 1.6200E+01 1.7400E+01 1.9937E-02 1.9756E-02

320.15 4.4997E-01 2.4880E+00 5.5293E+00 5.5293E-01 0.0000E+00 1.9100E+01 1.6300E+01 1.7500E+01 1.9943E-02 1.9754E-02

330.05 4.0004E-01 2.2496E+00 5.6234E+00 5.6234E-01 0.0000E+00 1.9100E+01 1.6400E+01 1.7500E+01 1.9941E-02 1.9744E-02

340.05 3.5000E-01 2.0007E+00 5.7164E+00 5.7164E-01 0.0000E+00 1.9100E+01 1.6400E+01 1.7600E+01 1.9947E-02 1.9752E-02

350.05 2.9996E-01 1.7428E+00 5.8099E+00 5.8099E-01 0.0000E+00 1.9200E+01 1.6400E+01 1.7600E+01 1.9949E-02 1.9747E-02

360.05 2.5005E-01 1.4762E+00 5.9036E+00 5.9036E-01 0.0000E+00 1.9200E+01 1.6400E+01 1.7600E+01 1.9935E-02 1.9734E-02

370.15 2.0001E-01 1.1994E+00 5.9968E+00 5.9968E-01 0.0000E+00 1.9200E+01 1.6400E+01 1.7600E+01 1.9943E-02 1.9732E-02

380.15 1.5000E-01 9.1358E-01 6.0907E+00 6.0907E-01 0.0000E+00 1.9200E+01 1.6400E+01 1.7600E+01 1.9944E-02 1.9734E-02

390.05 9.9988E-02 6.1830E-01 6.1838E+00 6.1838E-01 0.0000E+00 1.9200E+01 1.6400E+01 1.7600E+01 1.9949E-02 1.9756E-02

400.05 5.0008E-02 3.1394E-01 6.2778E+00 6.2778E-01 0.0000E+00 1.9300E+01 1.6400E+01 1.7500E+01 1.9951E-02 1.9744E-02


71

10.3. Analyzing Impedance Data

Impedance data can be graphed and analyzed using the ZView program. ZView must be installed

separately, from the software CD. ZView provides several tutorials on the graphing and analysis

of impedance data.

ZView Notes:

To display impedance data while measurements are being performed, start ZView and locate the

item in the toolbar that shows ‘No Active Data’. Click on the drop down box and select

~FlowCell 3 to display the live data as it is being measured by the FlowCell program.

- Use Ctrl+A or Option | AutoScale All Graphs to rescale the graphs to match the data.

- To load FlowCell data files that contain impedance measurements, select File | Data Files...

and select FuelCell +FlowCell Files (*.fcd) as the file type.


72

Appendix A Rotometer Data Sheet

73

APPENDIX A – ROTOMETER DATA SHEET

Appendix A Rotometer Data Sheet

74

Documents

Model 857 Redox Cell Test System - Scribner