Experimental and computational analysis of thermal runaway behavior of lithium ion pouch battery at low ambient pressure

Safety issue concerning the “thermal runaway behavior” of lithium-ion battery (LIB) is a major concern of users. In this paper, the thermal runaway (TR) behaviors at different ambient pressures were studied. The thermal runaway onset time (t1) occured in advance as the ambient pressure decreased from 90 kPa to 50 kPa (90 kPa, 80 kPa, 70 kPa, 60 kPa, and 50 kPa). At 50 kPa, thermal runaway onset time of LIBs was 177 seconds earlier than that at 90 kPa. The values of heat release rate (HRR), total heat release (THR), battery peak surface temperature and peak flue gas temperature declined with the decreasing ambient pressure. Moreover, the peak concentrations of CxHy and CO increased with the decrease of ambient pressure, whereas the peak concentration of CO2 and NO showed the opposite trend. Based on the previous studies of the thermal analysis kinetics model of LIBs, a pressure correction factor kp was introduced to establish a prediction model for thermal runaway temperature at low pressure conditions. Based on the model output, the error of thermal runaway onset time t1 could be controlled within ±2 s, and the error of thermal runaway peak temperature Tmax could be controlled within ±2 °C. The experimental results were well consistent with the simulation results. The results of this study are beneficial to better reveal the thermal runaway behavior of LIBs under low ambient pressure.