Dynamics of multidimensional signals in lithium-ion battery during thermal runaway under various oven temperatures

In order to explore the failure behaviors of lithium-ion batteries (LIBs) during thermal runaway (TR) under various oven temperatures, this study conducts comprehensive oven box abuse tests to investigate the impact of oven temperature on the characteristics of multidimensional signals during battery failure processes. The temporal relationships among expansion force, voltage, and temperature are revealed across four distinct stages of the thermal abuse process. The results indicate that within the oven temperature range of 150 °C to 250 °C, the LIBs invariably undergo venting, with the venting force ranging from 4000 N to 6422 N. Furthermore, the voltage of the batteries remains relatively stable at approximately 3.33 V before venting. An Internal short circuit and TR events occur once the oven temperature exceeds 180 °C, and the corresponding TR trigger temperatures are approximately 232 °C. Moreover, the abnormal force can be utilized as the earliest warning indicator prior to venting, and the lead time for expansion force warning signals decreases with increasing oven temperature in batteries undergoing TR. This study investigates multidimensional signals to effectively identify battery failures, deepening the understanding of the TR behaviors of batteries under different oven temperatures, and providing valuable insights for early warning and safety design of battery systems. •Safety performance of lithium iron phosphate (LFP) batteries is evaluated.•Critical oven temperature for thermal runaway in LFP batteries is determined.•Effect of oven temperature on dynamics of multidimensional signals is revealed.•Expansion behavior during failure at different oven temperatures is quantified.•Force signal serves as better warning indicators under lower oven temperature scenarios.