Study on the thermal radiation tolerance characteristics of lithium-ion batteries

With the extensive use of lithium-ion batteries (LIBs) in electrochemical energy storage systems and electric vehicles, their safety concerns have gradually emerged. Once LIBs undergo thermal runaway (TR), they can potentially trigger fire and explosion accidents, presenting substantial safety hazards. Regarding the issue that LIBs may experience TR due to external fires or other high-temperature conditions, the study of their thermal runaway tolerance characteristics under different degrees of external thermal radiation triggering conditions is of great significance in guiding the safe design and operation of LIB systems. Tests on lithium iron phosphate (LFP) and nickel manganese cobalt (NCM) batteries under the influence of different degrees of thermal radiation were conducted to obtain the typical phenomena, thermal radiation tolerance characteristics and tolerance zones of the abovementioned two LIBs after thermal runaway. Experimental results demonstrate that the thermal radiation tolerance thresholds of the NCM batteries and LFP batteries are 1.158 kW m^-2 and 1.88 kW m^-2, respectively, suggesting that LFP batteries exhibit superior thermal radiation tolerance compared to NCM batteries. Furthermore, prediction models for the duration of external thermal radiation exposure tolerated by NCM and LFP batteries were developed based on the experimental datasets; the models demonstrated a high goodness-of-fit (R ² = 0.96166 and 0.97698, respectively), validating their predictive accuracy. This research can provide guidance for the safety and protection of LIBs under external thermal radiation conditions (such as external fire and direct sun), which is of great significance for their safe operation.