Rupture and combustion characteristics of lithium-ion battery under overcharge

To clarify the evolution of thermal runaway of lithium-ion batteries under overcharge, the prismatic lithium-ion batteries are overcharged at various current rates in air and argon. The whole process with the charge rate higher than 0.1C in air includes three parts, which are expansion, rupture and combustion processes, respectively. The expansion process can be divided into two stages based on the change of surface temperature, and the temperatures at cell burst point are very close at various charge rates. The rupture process begins from the battery burst point. The pressure generated by rupture is less than 61 kPa at different charge rates, while it can reach 389 kPa in the following combustion process at 1C. The combustion process can be divided into four stages based on the obvious change of combustion phenomenon, which are ignition, violent combustion, stable combustion and extinguishing, respectively. Combustible gas was mainly CO, accounting for 32%. Three element factors of combustion under overcharge are clarified: combustible spouted out from the battery, high temperature electrode active substance, and oxygen in the environment, respectively. The results of this work can provide some information for the safety and fire protection of lithium-ion-battery based devices.