Battery Fire Risk Assessment

Lithium ion batteries (LIB) are crucial for future power systems and are being adapted across a span of applications in the ISS, planetary and earth science missions. Their prevalence requires the evaluation of their severe hazards in light of the unique spacecraft environment (reduced gravity, low pressure, high oxygen, limited egress opportunities, etc.). A LIB under an abuse condition can rupture and eject electrolyte vapor that can result in a flammable mixture of toxic gases that can subsequently ignite and burn. These hazards can pose an immediate risk to both the health of the crew, life support equipment and hardware. To evaluate the risks of a LIB fire in a spacecraft, this work will focus on quantifying the failure characteristics in LIB, such as, peak heat release, total energy release and combustion products. Heat release rates provides an estimate of fire growth and overall assessment of the risks to the crew and the vehicle. The peak heat release and total energy release from a single pouch cell and tablet fires are approximated using the t2 growth model and oxygen consumption calorimetry. Preliminary measurements show peak heat release rates between 2-15 kW and total energy levels between 218-290 kJ. This work has focused in quantifying the most energetic component of a LIB the electrolyte solvent, dimethyl carbonate mechanism (DMC). Flame temperatures reach above 1700 ? and major and minor gases were predicted, showing, a high level of CO2 and CO, in addition, other gases such as, acetylene (C2H2), ethylene (C2H4) and ethane (C2H6), will all be prevalent in a fire. Measurements of heat release rates and the gaseous species calculated will be used to estimate the impact that a fire has to the health of the crew member and the vehicle by calculating pressure rise and environmental temperatures.