Thermal characteristics of thermal runaway for pouch lithium-ion battery with different state of charges under various ambient pressures

Aerial vehicles powered by lithium-ion battery (LIB) goes through various ambient pressures. Considering the influence of ambient pressure (p) on the thermal characteristics of pouch battery during thermal runaway (TR), a series of experiments are performed to study the thermal characteristics of TR for commercial pouch LIBs with different state of charges (SOC) under various pressures. Based on the thermal analysis and experiment investigation, the thermal contribution of decomposition energy (Qd) and oxidation combustion energy (Qco) to peak battery temperature Tmax in TR is established. It is found that Tmax is determined by Qd and directly proportional to Qd, as well as affected by Qco. Sufficient concentration of O2 and ratio of combustible emitted gases are the necessary for high values of Qco. Besides, Qco increases in direct proportion to both p and SOC, and it leads to the increase of Tmax through the heat feedback. The area distribution model of TR hazards under various SOCs and pressure conditions is also established, and it can be used for evaluating and predicting the TR hazards under various conditions. Moreover, some mitigation measures and suggestions LIB safety and the decrease of TR hazards are proposed.