Influence of Ambient Temperature on Multidimensional Signal Dynamics and Safety Performance in Lithium-Ion Batteries During Overcharging Process

Ambient temperature significantly influences the safety performance of lithium-ion batteries (LIBs), particularly their thermal runaway (TR) behaviors. Yet, the complexities of multidimensional signal dynamics in overcharged LIBs under different ambient temperatures are not well understood. In this study, we performed comprehensive overcharging abuse tests under cold (-10 °C and 0 °C), normal (20 °C), and high ambient temperatures (60 °C), to investigate the evolution of multidimensional signals of expansion force, gas concentration, surface temperature, and voltage. Results show that TR events are not triggered at ambient temperatures of −10 °C and 0 °C, with the maximum temperatures and corresponding rise rate reaching only 125 °C and 0.5 °C/s, respectively. In contrast, for batteries undergoing TR, the maximum temperatures and rates of temperature increase peaked at 410.3 °C and 20.6 °C/s, respectively. The ambient temperature has a minimal impact on the venting force of the battery, which varies from approximately 9500 N to 10000 N, primarily driven by an increase in internal gas pressure during overcharging—a factor relatively unaffected by temperature changes. After safety valve activation during overcharging, Hydrogen (H2) is consistently the first gas detected immediately across all ambient temperature scenarios. Additionally, an increase in ambient temperature results in earlier detection of abnormal expansion and venting behaviors, characterized by lower venting voltages and higher venting temperatures. This study contributes to a deeper understanding of battery failure mechanisms under various ambient temperatures and informs the development of early safety warning strategies for LIBs during the charging process.