Energy distribution characteristics of thermal runaway under different environment pressures for lithium-ion batteries

As a critical parameter for thermal runaway (TR), heat energy is the key factor in initiation TR and the propagation hazards in lithium-ion battery modules. The characteristics of energy generation and distribution and the quantitative relationship between energies under different ambient pressures (APs) during TR are not available. A series of experiments were conducted in an adiabatic bomb calorimeter with N2 and air under various APs. Notably, the values and distribution ratios of energy were quantified, and an innovative energy distribution model for TR under different APs was proposed. The results show that majority of energy from decomposition and combustion is released into the battery and environment systems, respectively. There is more than 99 % energy increment of battery from decomposition under different APs. The main increase of energy in environment comes from combustion, at approximately 67.27 %, and will continue to increase as the combustion becomes more intensive. With the variation of AP, combustion increases, resulting in a variation in the distribution proportion of TR energies. A model for TR energy release rate and its influencing factors was established and quantified. In addition to reducing the total amount of heat released during TR, a lower energy release rate of can effectively reduce the accumulation and sudden surge of TR hazards.