A comparative study on multidimensional signal evolution during thermal runaway of lithium-ion batteries with various cathode materials

Cathode materials significantly affect the failure behavior of lithium-ion batteries, but there is a lack of comparative research on the multidimensional signal evolution for batteries with various cathode materials when subjected to thermal runaway (TR). This study investigates the effect of cathode materials on battery safety properties by conducting overheating and overcharging abuse experiments on LiNixCoyMn(1-x-y)O2 (NCM 523, 622, and 811) as well as LiFePO4 (LFP) batteries. The multidimensional signals, including expansion force, gas concentrations, temperature, and voltage, are comprehensively and quantitatively analyzed. The results demonstrate that expansion force shows the earliest anomalies regardless of the cathode material in both abuse conditions. Gas can be detected after venting, followed by significant anomalies in voltage and temperature. Additionally, under overheating conditions, LFP cells exhibit the longest TR warning time of 677 s. However, the force anomaly-based warning method is more suitable for low-nickel NCM cells under overcharging scenarios. Specifically, NCM 523 cells achieve an overcharging warning time of 992 s at temperatures as low as 42.9 °C, and hold the highest venting force of 9859 N and venting temperature at 114.1 °C. On this basis, a hierarchical warning strategy based on multidimensional signal fusion is proposed. This study provides valuable insights into TR early warning and safety management in LIBs with different cathode materials.