Revealing thermal runaway characteristics of ultrahigh-power lithium-ion battery by a multi-stage recognition modeling method

Ultrahigh-power lithium-ion batteries (LIBs) hold promising applications in military fields such as directed energy weapons and electromagnetic launch systems, and the safety of ultrahigh-power LIBs is a critical concern in military fields. Currently, comprehensive insights into the thermal runaway (TR) characteristics of ultrahigh-power battery are lacking, let alone the evolution of these characteristics with aging. To fill the above gaps, a modified multi-stage recognition TR modeling method is proposed, which is adopted for in-depth analysis of the TR characteristics of ultrahigh-power LiFePO4 (LFP) battery and the evolution of TR characteristics with aging under ultrahigh-rate discharge conditions. It is shown that compared to normal LFP battery, the onset temperature of TR of ultrahigh-power LFP battery is relatively higher. But once the onset temperature is reached, the TR process is more intense. Moreover, the onset temperature of TR ultrahigh-power LFP battery decreases with ultrahigh-rate discharge aging, which means it is more prone to TR. This work provides valuable insights into TR characteristics evaluation and thermal management for ultrahigh-power batteries.