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©2014 LG Fuel Cell Systems Inc.
The information in this document is the property of LG Fuel Cell Systems Inc. and may not be copied or communicated to a third
party, or used for any purpose other than that for which it is supplied without the express written consent of LG Fuel Cell
Systems Inc.
This information is given in good faith based upon the latest information available to LG Fuel Cell Systems Inc. No warranty or
representation is given concerning such information, which must not be taken as establishing any contractual or other
commitment binding upon LG Fuel Cell Systems Inc. or any of its subsidiary or associated companies.
This document does not contain any Export Controlled Data.
LG Fuel Cell Systems SOFC Technology and SECA Program Update
2014 SECA Workshop, 22 July 2014
Richard Goettler
LG data
Outline
● LGFCS Business Activities - 220 kW test
● Degradation Mechanisms and Mitigation ● Cathode
● Anode
● Primary Interconnect
● Cell-Stack changes for lower cost
● Strip Reliability ● Probability of failure predictions
● Residual strength of substrates
● Block Testing Update
LG data
Phases of the business supported by SECA
Commercial Phase
• Facility expansion (all types)
• Supply-chain expansion
• Sales / Installation / Service
capability
• Product scaling
• Market expansion
EIS3) Phase
• Adjustments to key components /
subsystems from IST results
• Deploy up to five field test systems
at “friendly” locations in North
America
• Build initial manufacturing facility
• Active supply-chain management
• Secure first order for a
commercially available fuel cell
power system
500kW – 1MW Field Tests
SECA supported lower ASR, in-
block reforming and degradation
improvements
•1) IST : Integrated String Test 2) VOC : Voice of the Customer 3) EIS : Entry Into Service
IST1) Phase
• Design, Build and Demonstrate
a SOFC power system from
fuel in to AC power out (1MW
Design)
• Further development of key
components / subsystems
• Accelerate EIS activities in
parallel with development
• North America Market
Assessment (VOC Meetings)2)
~220 kW grid connected test
Cell/stack technology for IST reduced to
practice under SECA (19 kW testing)
LG data
LGFCS Integrated String Test Schedule
2014 Key Program Milestones Update Fuel Cell Vessel 1 (FCV-1): emulator blocks plus 1 active block for systems commissioning
Fuel Cell Vessel 2 (FCV-2): fully loaded with active block for 220 kW
Apr May Jun Jul Aug Sep Oct Nov Dec Jan‘15 Mar Feb Mar
•FCV-1
Build
•FCV-1 Installation
•FCV-1 Cold Commission
•(check point by points)
•FCV-1
Installation
•FCV-1
Commission •Hot Commission
•IST (FCV-2)
Demonstration •FCV-2
Installation
IST Test
•All Hardware Installed/Connected, Control and
Safety System Operational, HAZOP / Safety
Assessments Complete, Commissioning Plan
Complete, and Commissioning Team Resources
Identified and Allocated
•FCV-1 Build
•Substrate printing •Strip + Block/FCV Assembly
LG data
Commissioning of IST Subsystems is Progressing Fuel Processor commissioning completed
FCV1 turbogenerator assembly under test, controls system completed
FCV2 turbogenerator under test
Block assembly for FCV1 in progress
All substrates printed for FCV2, strip build underway
Power electronics installed, grid connected, commissioning starting
2013 CAD rendering 2014 System Integration
Outdoor IST Test Pad
LG data
Outline
● LGFCS Business Activities - 220 kW test
● Degradation Mechanisms and Mitigation ● Cathode
● Anode
● Primary Interconnect
● Cell-Stack changes for lower cost
● Strip Reliability ● Probability of failure predictions
● Residual strength of substrates
● Block Testing Update
LG data
Product Durability Strategy
● End of Life ASR = 0.42 ohm-cm2 to meet
efficiency requirement
● Assumes constant power over service life
● Degradation rate target based on starting
ASR and required stack life to meet cost
● Lifetime improved by reducing degradation
mechanisms and/or lowering initial ASR
Plant Operation Strategy
0%
10%
20%
30%
40%
50%
60%
70%
0 1 2 3 4 5
Time, Years
An
od
e L
oo
p E
ffic
ien
cy
50%
60%
70%
80%
90%
100%
110%
120%
Po
we
r O
utp
ut,
% R
ati
ng
0.0081 ohm-cm2/1000 hrs
2 Year Design Life
0.003 ohm-cm2/1000 hrsPower Output
Efficiency
0.2 0.21 0.22 0.23 0.24 0.25 0.26 0.27 0.28 0.29
2
3
4
5
Starting ASR, ohm-cm2
Serv
ice L
ife, y
ears
Required ASR Degradation Rate
ohm-cm2/1000 hours
0.0130-0.0140
0.0120-0.0130
0.0110-0.0120
0.0100-0.0110
0.0090-0.0100
0.0080-0.0090
0.0070-0.0080
0.0060-0.0070
0.0050-0.0060
0.0040-0.0050
0.0030-0.0040
0.0020-0.0030
0.013 0.012
0.004
0.005
0.006
0.0070.008
0.009
0.0110.010
0.003
For starting ASR 0.29 ohm-cm2
LG data
Ongoing durability testing at pentacell scale used to understand degradation contributions
● Impedance measured at ~ 1000 hour intervals
● Resistance, capacitance, and Warburg elements to represent behavior
● Estimates of degradation contributions can then be charted over the life of the test
● Cathodic mechanisms dominate
3
Secondary
Interconnect
Primary
Interconnect
Active Cell
Air Distributor
Bus Rod
Voltage Tap
Lead-outs
Fuel Inlet
Manifold
Fuel Outlet
Manifold
•PCT150 and PCT189: 925C, 4.0 Bara
800C 925C
LG data
Cathode Degradation Mechanisms
● Localized densification near electrolyte interface
● MnOx segregation and/or migration
● MnOx valence changes
● Moisture effect
● Cr effect
● Ionic phase degradation
● Material diffusion
LG data
Cathode Densification vs. Testing Conditions
● Kinetics is a key factor for baseline LSM cathode densification
PCT63B 16,000 hrs (860C)
5 µm
PCT63A 8,000 hrs(860C)
PCT89 16,000 hrs (800C)
PCT150 7,000 hrs(925C)
Tem
p, C
Time, hrs
8,000 16,000
800
900
850
Densification
Densification
TB
D
LG data
MnOx Segregation/Migration Observed Across Temp. Range
Epsilon 800C
As-fab 2,000hrs 8,000hrs 16,000hrs
800C
6,500 hrs
860C
900 -
925C
LG data
Minor amount of Mn exsolutes from LSM near interface
● Data from baseline LSM cathode
● Tested at 800oC for 16,000 hours under simulated system
conditions
TEM image
Cathode/CCC
interface
LG data
MnOx accumulation at interface not observed under OCV
● Tested ~5000 hrs at 925oC and 4 bar
Reference cell w/o current load - MnOx at cathode/CCC interface
Active cell with current load - MnOx at electrolyte
- MnOx elimination from bulk cathode
Mn
LSM
ele
ctr
oly
te
ele
ctr
oly
te
LG data
Accelerated Testing of Densification Mechanism
Footer
600hrs 2000hrs 400hrs
● Symmetric button cell tested under selected conditions to accelerate densification
● 860C, 16000 hr densification at NOC matched in 1200 hours accelerated
Thickness for NOC 860C/16,000 hrs
400hrs 600hrs 2000hrs
Ba
se
lin
e
Ca
nd
idate
LG data
Long-term cathode material studies ongoing at different temperatures
● Candidate EIS cathodes show benefit at low temperature, similar degradation rates at high temperature
● Still seeking understanding of major degradation mechanisms across temperature ranges
● Densification not a major contributor at low temp.
● Further documenting the variation of MnOx as function of temp. and LSM cathode composition
•Baseline Cathode
•Candidates
•Baseline Cathode
•Candidates
LG data
Triple bundle test with candidate cathodes showing improved durability trends
● Only change from baseline cell technology was the cathode
● Rates consistent with cathode degradation studies
● Projects to a 2-½ year life across block temp. profile and for block starting ASR
● Further durability extension with anode and interconnect changes
700
720
740
760
780
800
820
840
860
880
900
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0 1000 2000 3000 4000 5000
Ave
rag
e T
em
pe
ratu
re,
ºC
AS
R,
oh
m-c
m2
Elapsed Time, hours
Bundle ASR: ATBT3 - Cathode Study Triple Bundle Test
3167-5, Bundle Degradation Rate = 8.5 micro-ohm-cm²/hr
3167-52, Bundle Degradation Rate = 7.1 micro-ohm-cm²/hr
3168-164, Bundle Degradation Rate = 6.5 micro-ohm-cm²/hr
3167-5, Average Temperature = 834.5ºC
3167-52, Average Temperature = 858.3ºC
3168-164, Average Temperature = 882.2ºC
Mai
nte
nan
ce S
hu
tdo
wn
Ho
t St
and
-By
Mai
nte
nan
ce S
hu
tdo
wn
Time = 5082 Bundle 1: Bundle 2: Bundle 3:
hours 3167-5 3167-52 3168-164
Average Temperature 834.5 858.3 882.2 ºC
Bundle Degradation Rate 0.52% 0.43% 0.35% %Power/1000 hrs
Bundle ASR 0.0085 0.0071 0.0065 ohm-cm²/1000 hr
1 Bara
LG data
Single Layer Anode Selected for EIS Business Phase
925oC 7000hr 925oC 5000hr As reduced
● Exhibits more uniform microstructure than baseline bi-layer at similar test times
● Accelerated testing being developed for quicker screening of final anode compositions
H2: 14%, CO:7.5%, H2O: 50%, CO2: 25.5%, N2: 3%
LG data
Single Layer Anode Showing Improved Durability
● Lower ASR change and degradation rate after accelerated testing
● The results were repeated
TPB was generated from 3D database
770
790
810
830
850
870
890
910
930
950
970
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0 200 400 600 800 1000 1200 1400
Te
mp
era
ture
, ºC
AS
R,
oh
m-c
m2
Time, hours
A1: PC98-3, Single Layer
A2: PC74-4, Baseline Bi-layer
BottomTemperature
Normal
operation
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
As-reduced 925C, 90%FU,1000hr
925C, 80% FU,5000hr
TPB
Den
sity
, m/m
3
Active TPB
Accel.
Test
Acceleration Testing at 925C/90% Fuel Util. Return NOC NOC
DASR, ohm-cm2
(before/after accel.)
Baseline Bi-layer anode 0.018
Single layer anode -0.003
Similar TPB for Accel. vs NOC Test
LG data
•Single cell test
Improved Redox Tolerance is Sought for Anode Protection Simplification
● Tolerate low probability of
occurrence emergency events
● Anodes tested
● Baseline single layer anode
● Modified 1: composition
modification
● Modified 2: microstructure
optimization
● Screening tests
● Pellet test
● Single cell test
•Pellet test: 5 redox cycles for different pellets
Baseline
Modification 2
•Redox Cycle: 900C, 3 hrs oxidation, N2 purge
LG data
650
700
750
800
850
900
950
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0 200 400 600 800 1000 1200
Tem
pera
ture
, ºC
AS
R,
oh
m-c
m2
Time, hours
PIC ASRs: PCT196_4X
PC101-2: baseline
PC106-1: Barrier A
PC106-4: Barrier B
Temperature
Primary Interconnection Modification to Further Reduce Materials Migration
● Barrier layer modification does not increase the ASR
● Longer-term testing at most aggressive bundle conditions to accelerate mechanisms
● Post-test evaluations versus time to confirm benefits
Via-based
interconnect design
LG data
Outline
● LGFCS Business Activities - 220 kW test
● Degradation Mechanisms and Mitigation ● Cathode
● Anode
● Primary Interconnect
● Cell-Stack changes for lower cost
● Strip Reliability ● Probability of failure predictions
● Residual strength of substrates
● Block Testing Update
LG data
Lower ASR technology demonstrated at bundle-scale
● ASR reduction at 4 bar of >0.04 ohm-cm2
● Meets ASR targets for initial products
● Optimized LSM compositions (lower Rp)
● Modified primary interconnect design
● Single layer anode
● Durability testing at higher current density design point
0.10
0.15
0.20
0.25
0.30
0.35
0.40
790 810 830 850 870 890 910
AS
Rs
, o
hm
-cm
2
Average Bundle Temperature, ºC
PBT12 (WRD3261-25) - Bundle ASR
PBT5 - Avg ASR @ 860ºC = 0.291 ohm-cm2
PBT12 - Avg ASR @ 860ºC = 0.243 ohm-cm2
20-Jun-14 19:45:56
Phase 1
selected IST technology
Combined Phase 2
ASR improvements
0
50
100
150
200
250
300
350
400
450
500
0 200 400 600 800 1000
Bu
nd
le P
ow
er,
Wa
tts
Elapsed Time, hours
Bundle Power: PBT12 (WRD3261-25)
4 Bara, 860ºC Average
380 mA/cm2 530 mA/cm2
4 Bara
LG data
Print pattern changes to optimize power output
● Smaller primary interconnect dimension has lower ASR contribution
● Decreased cell pitch gives a lower in-plane resistance
● Lower ASR combined with increased active area per tube gives a potential increase in power output up to 26%
● Printing trials with 0.95 mm PIC in process
0.20
0.22
0.24
0.26
0.28
0.30
0.32
0.5 0.6 0.7 0.8 0.9 1 1.1 1.2
Re
pe
at
Un
it A
SR
, o
hm
-cm
2
PIC Dimension, mm
Repeat Unit ASR Reduction vs PIC Dimension(Constant Efficiency)
300
320
340
360
380
400
420
50 55 60 65 70 75 80 85 90 95
Po
we
r p
er
6 T
ub
e B
un
dle
, W
att
s
Number of Active Cells per Tube
Bundle Power for Smaller PIC Dimension(Constant Efficiency)
0.65 mm PIC
0.80 mm PIC
0.95 mm PIC
1.1 mm PIC (current design)
LG data
Increasing In-Block-Reforming (IBR) to increase power density and manage Block ∆T
● Thermal integration enables operation at higher current density while maintaining reasonable stack temperature
● Higher power density means less stack, smaller package, reduced size of BOP components
● Single turbogenerator serves greater kW
● May also minimize stack temperature extremes at the hot and cold end which may be beneficial for performance and durability considerations.
0
10
20
30
40
50
60
70
80
90
100
Current/ISTTechnology
Next Generation CellASR
50% IBR and LowerASR
100% IBR and LowerASR
Block ASR = 0.32 Block ASR = 0.27 Block ASR = 0.27 Block ASR = 0.24
Bundle ASR = 0.29 Bundle ASR = 0.25 Bundle ASR = 0.25 Bundle ASR = 0.22
19.522.8 25.2
26.9 kW
81
94
73
Stack DT, ºC, 31
Impact of Lower ASR and IBR
Block Power
(5 strips)
Block ∆T
LG data
All reforming within bundle Current approach: reforming external to bundle
IBR development activities addressing Thermal Stresses and Carbon Avoidance
● Multi-physics modeling
● Bundle test at 50% and 100% IBR performed ● Nearly full conversion of CH4
● Lower power at 100% IBR from Nerst potential difference
200
220
240
260
280
300
320
340
360
380
400
0 200 400 600 800 1000 1200
Bu
nd
le P
ow
er,
Wa
tts
Elapsed Time, hours
Bundle Power Comparison with and without In Block Reforming
PBT5 (Simulated Reformate)
PBT8 (50% IBR after 300 hrs)
PBT11 (100% IBR from 390 to 590 hrs)
4 Bara, 860ºC Average
PBT11 on 100% IBRCase
Bundle
Power Bundle DT
Reformate 322 W 20ºC
50% IBR 320 W 12ºC
100% IBR 316 W 6ºC
Lower thermal gradients with
incorporation of in-block reforming
(inlet substrate shown)
LG data
Further Reduction in Cell ASR using Nickelate Cathodes
● Phase instability under operating conditions has been major issues
● Technical approaches to improve nickelate phase stability
● A-site doped Pr2NiO4+d
(Pr0.25Nd0.75) A-site ratio is phase stable1, (Pr0.5Nd0.5) exhibits instability
● Addition of B-site dopants provides phase stability for A-site (Pr0.5Nd0.5)
Nickelate provides ~0.02 ohm-cm2 lower ASR
than most favorable LSM-based cathode
1. Advances in Solid Oxide Fuel Cells III, Ceramic Eng. and Sci. Proc., 28(4) 2008.
LG data
Outline
● LGFCS Business Activities - 220 kW test
● Degradation Mechanisms and Mitigation ● Cathode
● Anode
● Primary Interconnect
● Cell-Stack changes for lower cost
● Strip Reliability ● Probability of failure predictions
● Residual strength of substrates
● Block Testing Update
LG data
FEA Validation and CARES Prediction ● FE Stress Modelling: Validation at RT
● CARES Prediction: 4pt bend test at RT
MMA Substrate Gen 2
Ratios (Exp./FE)
Kmax (N-mm)
Bare Substrate (avg. strength from 30 test)
1804/1777.6 =1.01
Glassed Substrate (120µm thick glass layer and avg. strength
from 6 test)
1831/2102.5 = 0.87
Full Printed Substrate (avg. strength from 15 test)
2504/2726.5 = 0.92
•Input from 4pt bend test on MMA
Substrate :
•σ0 = 57.48, m = 16.48
•CARES Output:
•Pf, CARES prediction = 63%
•Pf, expected = 63.2% (Good Agreement)
LG data
Very Low Pf of Substrate under Operating conditions (Fast fracture)
● Conservative assumptions of Weibull
parameters – used RT values under 2
conditions
● Tube specification (MoR= 29MPa,
m=15)
● Actual Tube MOR (MoR= 1.31MPa,
m = 14.98)
● Bundle thermal boundary conditions
mapped in ABAQUS.
● Peak stresses for substrate 2 of top
bundle in strip 5 (worst case)
MMA
Substrate
(Tube #)
Max. Stress
(MPa)
Pf (%),
Actual
Pf (%), Tube
Specification
1 6.40
0.86e-11 0.18e-11
2 15.27
0.51e-8 0.107e-5
3 9.10
0.13e-10 0.27e-8
4 7.40 0.10e-9 0.25e-7
5 5.95
0.95e-11 0.19e-8
6 7.54
0.16e-9 0.33e-7
LG data
Low Pf of Substrate under Normal Operating Conditions (Slow fracture)
● Conservative assumptions of Weibull parameters – used RT
values under 2 conditions
● Used actual high temperature SGC parameters from ORNL
MoR (MPa) m
Porous
MMA
41.31 14.98
Dense MMA 248.61 9.38
Future Work:
● FEA for dense parts+ CARES prediction for a full strip
● Low risk of failure of dense parts as strength 4X
substrate and similar SCG parameters and >Kic
● Block transient stress states
•SCG test- 900°C+Air
Pf in 10-4 range for substrate 2 Room Temp. Weibulls
LG data
Phase 2 Block Test: Post-test Reliability Assessment
Approach: Measure RT 4-pt and compare to
bare substrate of identical lot.
● The ratio of Tested Substrate: As-rec’d Bare
Substrate is ~1.3-1.5, typical of ratio for as-
processed substrates
● This indicates little or no loss in strength over the
nominal 3000 hours of operation.
Mechanical Properties
• Fracture can start from surface defect as well as
from volume imperfection.
• All the data (~600) from Strip 1, 3 and 5 put together
show a good linear fit.
Strip
No. Lot No.
No. of Test
Specimens
Strength Ratio (±
95% Conf. Int.)
1 22 186 1.32 ± 0.019
1 32-2 19 1.32 ± 0.048
3 32-1 196 1.46 ± 0.014
5 32-2 36 1.39±0.15
5 24 132 1.40±0.14
5 25 33 1.53±0.07
MoR (MPa) m
Post-test 46.76 13.43
(Mix of Gen1 and Gen2 substrates)
LG data
Outline
● LGFCS Business Activities - 220 kW test
● Degradation Mechanisms and Mitigation ● Cathode
● Anode
● Primary Interconnect
● Cell-Stack changes for lower cost
● Strip Reliability ● Probability of failure predictions
● Residual strength of substrates
● Block Testing Update
LG data
Block Testing Matching Product Cycle, Components and Operating Conditions
•Turbo-Generator
Fuel Cell
Cathode
Fuel
Cell
Anode
OGB
Anode Ejector
Cathode Ejector
Turbo-Generator
RRFCS NG “Dry Cycle” Configuration
Auxiliary
Ejector
R
E
F
O
R
M
E
R
R
E
F
O
R
M
E
R
Auxiliary
Heat Exchanger
Heat Source for Cathode Loop;
Partially-Spent Anode Gas,
Heated Cathode Loop Air,
and Hot Recycle
De-Sulfurized
NG
•Recuperator
•Initial design of block testing rigs
•Representative of cycle and components
•Not packaged for product
•One rig converted to match IST block design
•Allows testing of 3 blocks
•Fully representative of product
Derby, UK
LG data
3 Block Tests Supported by Current Program
● Two 15 kW tests – original block design ● Screening of cathode technology
● 1st test: Chromium mitigation, pipeline nat. gas and SCSO desulfurization (started July 2014)
● 2nd test: higher Chromium sources, pipeline nat. gas (starting Aug 2014) Similar Cr content as Phase 1 and Phase 2 block tests
● 3rd 4-strip test of combined cell technology for lower ASR and improved durability
● expected <0.75%/1000 hours
● Single layer anode, alternate cathode, primary interconnect redesign
0.00
0.20
0.40
0.60
Strip 1 Strip 2 Strip 3
Ch
rom
ium
(at
. %)
3000 hour Block Test (Ph. 2)1.1%/1000 hr power degrad.
Air flow, Temperature rise
through block
EIS
3
EIS
1
EIS
2
EIS
1
Baselin
e
EIS
2
Baselin
e
Baselin
e
LG data
Current Phase Block Test #1
● 4 Strip test with EIS cathode candidates
● 15.4 kW target value achieved
● ASR improved over Phase 2 test, especially at lower temp.
● Problems with BOP forced early shutdown
● NG-SCSO connectivity
● Air compressor failure
700
720
740
760
780
800
820
840
860
880
900
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
0 10 20 30 40 50 60 70 80 90
Cath
od
e A
vg
Tem
p, ºC
Blo
ck P
ow
er,
kW
Time on Load, hours
4-Strip Test Block Power
Total Power
Cathode Average Temperature
0.10
0.20
0.30
0.40
0.50
0.60
790 810 830 850 870 890 910 930
1/2
Str
ip A
vg
AS
R,
oh
m-c
m2
Temperature, ºC
1/2-Strip ASR vs Temperature
Phase 2 Block Test (343 hrs)
Current Program Test
Strip Manufacturing Test Data (1 Bara)
LG data
Conclusion
● Cell and stack developments supported by SECA are moving into 220 kW-scale system integration testing
● Degradation rates being reduced, further verification through accelerated and longer-term testing across testing platforms
● Active layer materials in final screening for inclusion in next business phase of system field testing
● In-block reforming coupled with lower ASR cell technology provides significant cost reductions – focus of next Phase.
LG data
Acknowledgements
● Special thanks to LGFCS project manager Patcharin Burke and the entire SECA program management team
● Current and former LGFCS SECA partners: Case Western Reserve University, University South Carolina, University Connecticut and Oak Ridge National Laboratory
LG data
Acknowledgements_Continued
● This material is based upon work supported by the U.S. Department of Energy, National Energy Technology Laboratory under Award Number DE-FE0000303 and DE-FE0012077.
● Disclaimer: This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government of any agency thereof.