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Flammable Gas AnalysisUN Lithium Battery Working Group
Matthew Karp and Joseph Sica
International Aircraft Systems Fire Protection Working Group
April 2021
Test Procedure
2
•21.7 liter stainless
steel pressure vessel
•General test
procedure found in
Thermal Runaway
Initiation Methods for
Lithium Batteries
Scope of Test
3
To measure the volume and composition of thermal runaway vent gas across
various states of charge (SoC) and heating rates
Cell Style Nominal Voltage, V Capacity, Ah Power, Wh
Cylindrical 3.7 2.6 9.62
Pouch 3.7 4.8 17.76
Test Setup Pouch Cell
4
75 watt heaterInsulated all sides asides top
Results – Pouch Cells
5
Volume of vent gas vs state of charge
R² = 0.9583
R² = 0.9773
R² = 0.7283
R² = 0.9678
0
0.5
1
1.5
2
2.5
3
3.5
0 10 20 30 40 50 60 70 80 90 100 110
Vo
lum
e o
f ga
s, L
State of charge
CO, L
CO2, L
O2, L
THC, L
Hydrogen, L
Methane, L
Ethylene & Acetylene, L
Ethane, L
Propylene, L
Propane, L
Butane, L
1-butene, L
Results – Pouch Cells
6
Percentage of vent gas vs state of charge
R² = 0.9509
R² = 0.8856
R² = 0.0225R² = 0.1362
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 10 20 30 40 50 60 70 80 90 100 110
Perc
enta
ge o
f ve
nt
gas
State of charge
CO, %
CO2, %
O2, %
THC, %
Hydrogen, %
Methane, %
Ethylene & Acetylene, %
Ethane, %
Propylene, %
Propane, %
Butane, %
1-Butene, %
Results – Pouch Cells
7
Pareto chart average volume of vent gas across all SoC
Results – Pouch Cells
8
Combustion energy if ignited vs state of charge by heating rate
Percent difference: 21%Total difference: 21.5 kJ
Percent difference: 15%Total difference: 6.7 kJ
Percent difference: 24%Total difference: 6.1 kJ
Percent difference: 78%Total difference: 6.7 kJ
0
20
40
60
80
100
120
0 10 20 30 40 50 60 70 80 90 100
Co
mb
ust
ion
En
ergy
, kJ
State of charge
5C/min
20C/min
Results – Pouch Cells
9
Combustion energy if ignited vs heating rate at 100% SoC
R² = 0.6565
75
90
105
120
135
0 5 10 15 20 25
Co
mb
ust
ion
En
ergy
, kJ
Heating Rate, C/min
Test Setup
10
100 watt heaterInsulated all sides asides top
Results – 18650 Cells
11
Volume of vent gas vs state of charge
R² = 0.8176
R² = 0.9102
R² = 0.9521
R² = 0.9813
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
0 10 20 30 40 50 60 70 80 90 100 110
Vo
lum
e o
f ga
s, L
State of charge, SOC
CO, L
CO2, L
O2, L
THC, L
Hydrogen, L
Methane, L
Ethylene & Acetylene, L
Ethane, L
Propylene, L
Propane, L
Results – 18650 Cells
12
Percentage of vent gas vs state of charge
R² = 0.8203
R² = 0.7703
R² = 0.9483
R² = 0.5474
0.0%
5.0%
10.0%
15.0%
20.0%
25.0%
30.0%
35.0%
40.0%
0 10 20 30 40 50 60 70 80 90 100 110
Perc
enta
ge o
f ga
s
State of charge, SOC
CO, %
CO2, %
O2, %
THC, %
Hydrogen, %
Methane, %
Ethylene & Acetylene, %
Ethane, %
Propylene, %
Propane, %
Butane, %
1-Butene, %
Results – 18650 Cells
13
Pareto chart average volume of vent gas across all SoC
Results – 18650 Cells
14
Combustion energy if ignited vs state of charge by heating rate
Percent difference: 48%Total difference: 2.9 kJ
Percent difference: -15%Total difference: -2.7 kJ
Percent difference: 15%Total difference: 5.9 kJ
Percent difference: 4%Total difference: 0.5 kJ
0.0
15.0
30.0
45.0
0 10 20 30 40 50 60 70 80 90 100 110
Co
mb
ust
ion
En
ergy
, kJ
State of charge
5C/min
20C/min
Results – 18650 Cells
15
Combustion energy if ignited vs heating rate at 100% SoC
R² = 0.8925
30.0
35.0
40.0
45.0
0 5 10 15 20 25 30
Co
mb
ust
ion
En
ergy
, kJ
Heating Rate, C/min
Conclusion
16
• Heating rate affects the combustion hazards due to thermal runaway
• Test in an inert environment (nitrogen) to collect the vent gases
before decomposition to measure the combustion hazard
