Thermal runaway induced by dynamic overcharge of lithium-ion batteries under different environmental conditions

The present study aims to investigate thermal runaway induced by dynamic overcharge of lithium-ion batteries (LIBs) with Li_x(Ni_0.3Co_0.3Mn_0.2)O₂ cathode under different environmental conditions. LIBs were overcharged with different charging ratios to thermal runaway in the ambient and adiabatic environment. The battery is more susceptible to thermal runaway in an adiabatic environment. The time T (apparent exothermic onset temperature) of the battery in an adiabatic environment was 160 s, 260 s, and 500 s shorter than that in the ambient environment. When T is detected, batteries need to be cooled within 14 min to prevent thermal runaway. Due to over-potential, the battery voltage will drop in the next stage after reaching the highest point. The inflection point voltage of the battery during overcharging is due to the deposition of metallic lithium in the anode graphite, which causes a significant potential shift of the anode. In the overcharging process, when the battery reaches the inflection point voltage, it must be terminated within 5 min and take measures to prevent thermal runaway. These results can render supports for understanding the overcharge mechanism and battery management system.