Firefighter Safety in Battery Energy
Storage System FiresErik Archibald, P.E.
Kevin Marr, PhD, P.E.
NFPA SUPDET
November 30, 2018
O.A. (DK) EzekoyeThe University of Texas at Austin
UTFRG
Judy JeevarajanUL
Daniel Gorham*Fire Protection Research
Foundation
Kevin MarrThe University of Texas at Austin
UTFRG
Ronald ButlerESSPI
Core TeamCasey GrantFire Protection Research
Foundation
Serhat BilyazComputational Modeling
Erik ArchibaldStructural Dynamics, Explosion Analysis
Cell Array Experiments
Tyler BuffingtonStatistical Modeling
Austin BairdFire Protection, Hazard Analysis
Robert KennedyDesign of Experiments,Testing
UTFRG Research Team
Energy Storage Grid Applications
Energy storage is an integral part of the next generation grid to improve grid performance and reliability, reduce energy costs, and reduce reliance on fossil fuels.
With the cost of lithium-ion batteries decreasing, Li-BESS are becoming more economical.
Li-BESS sites are being proposed in both outdoor and indoor locations. Smart Phone ~ 10 Wh
Laptop ~ 50-100 Wh
http://microgridmedia.com/wp-content/uploads/2016/02/Panasonic_BatterySmallToBig_535_330.jpg
Firefighter Safety Concerns
Firefighter Safety
Fire
Explosion
ElectricalToxicity
Stranded Energy
What are credible sequences of events that can result in explosive conditions?
What is the likelihood of such events?
How do results from limited tests translate to other ESS and installation sites?
How can cell/cell array tests be used to inform hazard assessment of full-scale systems?
Are there critical gaps in fire service SOGs/SOPs that increase risk to firefighters?
Do current SOGs/SOPs effectively mitigate explosion hazards?
ESS Incident in Belgium
Blum and Long (2016)
Hill, et al. (2017)
• Fire occurred Nov. 11, 2017 at a test site in Drogenbos, Belgium that had launched in July.
• 1 MW container supplied by Engie Ineo.
• What’s in the plume (toxicity)?
• Is this an explosion hazard?
• How do we suppress it?
• After suppression, are there electrical hazards?
http://www.energystoragejournal.com/belgiums-li-ion-ess-fire-cause-still-unknown-two-months-later/
Houston Rail Car Explosion
Explosion broke windows about 500 ft
awayApril 2017 – Houston Train Explosion, Union Pacific 53’ double stacked rail car
Car was carrying used li-ion consumer
batteries to recycling facility
Understanding the Hazard
Cell Failures
No Ignition
Immediate Ignition
Fire
Gas Accumulation
Extinction
Ignition in Rack
Explosion in Rack
Flammable Mixture Delayed Ignition
Ignition in Room
Explosion in Room
FAA FRC Experiment• 5000 18650 Cylindrical Cells
• ~ 40 kWh of energy storage
• Fire Resistant Container
designed to limit oxygen to
contain Class A fires
• Aerosol fire suppressant
extinguished fire at about 20
minutes
• Explosion occurs after 45
minutes
Cell FailuresImmediate
IgnitionFire Extinction
Ignition in Room
Explosion in Room
Yes Possible Explosion Hazard
Yes
No Fire Extinguished
Yes
Yes Ongoing Fire
No
Yes No Fire burns out
Yes Possible Explosion Hazard
No
No Gas dissipates
No No Hazard
Cell Failure Venting Immediate
Ignition
Fire Extinction Venting until Flammable Mixture
Modeling Scales
Cell Module Rack Room Site
• Thermal Runaway
• Gas CharacteristicsRunaway Propagation by:
• Conduction
• Convection
• Radiation
• Ventilation
• Gas Mixing
• Ignition
Fire Consequence:
• Heat release
• Structural Damage
Blast Consequence:
• Structural Damage
• Injuries
https://newsroom.edison.com/gallery/album?id=5420bb5cee750e68c201f1d6&t=photo&p=100&s=order
Need to characterize:
• Gas composition
• Gas release rate
• Amount of gas released
• Gas flammability
Somandepalli, Marr and Horn (2014)
Literature on Gas Characterization
H2, 28%
CO, 23%
CO2, 30%
HC, 19%
Maximum Explosion Overpressure
• Calculated based on gas mixture
properties in Cantera
• Calculate thermodynamic, equilibrium
pressure for constant volume,
adiabatic process
• Compared against experiment by
Somandepalli, Marr and Horn in 2014
Laminar Flame Speed
Flame speed calculated based on gas mixture properties using Cantera
Simple Model for Vented Gas Explosion
Energy Conservation
Mass Conservation
Burning Rate
NFPA 68 Kg Deflagration Index
Max rate of
pressure rise
Volume
Experiment data from Somandepalli, Marr and Horn (2014)
Hydrogen Methane Propane 100% SOC Vent Gas
Molar Mass (gm/mol) 2 16 44 26 †
Flammability in Air (%) 4 - 75 5 - 15 2 - 10 6 – 40*
Stoichiometric Ratio in Air (%) 17 % 9.5 % 4 % 19%†
Energy Content (MJ/kg) 141.8 55.7 50 52 †
Energy Content (kJ/L) 12 96 37 18 †
Burning Velocity (m/s) 3.2 0.40 0.46 0.49 †
Kg (m-bar/s) 250 46 76 65 *
Maximum Overpressure (bar-g) 6.8 7.1 7.9 7.1 *
Flammability ComparisonH2, 28%
CO, 23%
CO2, 30%
HC, 19%
† Calculated using mixture properties based on composition by Somandepalli et al.
* From Somandepalli et al.
Energy Density & Fire Load Density
Indoor dedicated storage
Storage Density: 55 𝑘𝑊ℎ
𝑚2
Gas Generation: 17.5 𝑚3
𝑚2
Fire Load Density*: 315 𝑀𝐽
𝑚2
20’ or 40’ Container
Storage Density: 170 𝑘𝑊ℎ
𝑚2
Gas Generation: 55 𝑚3
𝑚2
Fire Load Density*: 980 𝑀𝐽
𝑚2
FAA FRC Experiment
Storage Density: 5 𝑘𝑊ℎ
𝑚2
Gas Generation: 1.7 𝑚3
𝑚2
Fire Load Density*: 30 𝑀𝐽
𝑚2
*Fire Load Density due to battery gas releases only. Does not include battery self-heating or flammable packaging and other materials.
Fire Load Density of Dwelling ~ 780 𝑀𝐽
𝑚2
ScalesCell Module Rack Room Site
Thermal Runaway Propagation CFD Model of Mixing Blast Model
Cell to Cell
Propagation
Gas
Properties
Thermal
RunawayModule in Compartment
Models
Exp
erim
ents
Thermal Runaway Experiment & Models
Goals:
• Understand onset of thermal
runaway
• Model heat generation
• Predict onset of runaway
Experiments:
• Measure temperatures for
thermal runaway
Models:
• Equation for heat generation
Gas Characterization Experiments & Models
Goals:
• Determine composition and volume of gas
release
• Measure temperature of gases released
• Determine flammability properties of gases
Experiments:
• Cell thermal runaway in vessel
• Perform for different size, chemistry cells
Models:
• Cantera model of mixture properties
Propagation Experiments & Models
Goals:
• Model heat flux from cell to cell
• Model next cell thermal runaway
• Predict propagation rates
Experiments:
• Cell array thermal runaway
Models:
• Finite difference heat transfer model
Explosion Experiments & Models
Goals:
• Demonstrate explosion
• Validate explosion models
Experiment:
• Small vented explosion
Models:
• Thermodynamic Equilibrium
• 0D Explosion Model
Planned Work• Development of CFD models
– Module to module propagation– Rack to rack propagation– Gas dispersion
• Models of Consequences– Blast Overpressure– Structural damage
• Full-scale module experiment• Develop physical Li-BESS simulator
EXTRA SLIDES
FAA FRC Data