An investigation on thermal runaway behaviours of lithium-ion battery with Li(Ni_0.6Co_0.2Mn_0.2)O₂ cathode induced by overcharge under different heat dissipation conditions

Lithium-ion batteries (LIBs) are widely used, but there are few studies on their behaviour under different heat dissipation conditions. This paper comparatively investigates the electro-thermal behaviour of LIBs in air, quasi-adiabatic, and adiabatic environments during thermal runaway caused by overcharging. Our study reveals the internal mechanism of overcharging that leads to battery degradation. We find that the battery is more prone to thermal runaway under deteriorating heat dissipation conditions or with an increase in charging rate, but the state of charge (SOC) at the time of thermal runaway is not necessarily correlated with it. Regardless of the conditions, the battery develops a voltage plateau, and the temperature rises during this phase due to the decomposition reaction of the solid electrolyte interface (SEI) film or the electrolyte's reaction with the intercalated lithium. Inconsistent airflow and temperature can affect the battery's temperature and voltage during overcharging. Increased impedance, cathode destruction-including an increase in particle distance, dissolution and deposition of transition metals on the anode, and lithium precipitation on the anode's surface are significant reasons for the battery's degradation due to overcharge. These observations play a crucial role in the storage, transportation and use of LIBs in different environments.