Investigating the relationship between heating temperature and thermal runaway of prismatic lithium-ion battery with LiFePO₄ as cathode

As a core of safety issue on lithium-ion batteries (LIBs), thermal runaway (TR) can be easily induced when LIBs are exposed to high temperature environment. Clarifying the relationship between heating temperature and TR is crucial for improving the safety of LIBs. In this work, the impact of heating temperature on TR of the individual battery is revealed through experiments. Only safety venting is captured at 175 °C heating temperature owing to inadequate internal energy change of the LIB, whereas TR is observed to occur once the heating temperature is higher than 200 °C. With the increase in heating temperature, the time interval between safety venting and TR becomes shorter, and the temperature difference within the LIB exhibits a downtrend. In addition, contributions of the self-generated heat to trigger TR at different heating temperatures are identified. The heating temperature of 200 °C results in the highest self-generated heat before TR, which is found responsible for inducing more exothermic reactions within the LIB to generate sufficient heat to trigger TR. Furthermore, the critical input energy for triggering TR is analyzed and obtained. The findings provide new insights into the impact of temperature on TR and can benefit the safety monitoring of LIBs.