Abstract: Thermal runaway of lithium-ion battery is the primary factor causing electric vehicle fire accidents. In this paper, the risk of thermal runaway fire of automotive Lithium-ion battery and its suppression and extinguishing methods are summarized, and the fire extinguishing experiments of C6F12O and water mist on thermal runaway fire of ternary lithium-ion battery are carried out. The results show that the maximum surface temperature exceeds 500 ℃ and the maximum surface temperature rise rate reaches 18.93 ℃/s when the ternary lithium battery is thermally out of control; Both C6F12O and water mist can effectively extinguish the initial open fire of the battery, but the battery reignited within a few minutes after the fire was extinguished. The two extinguishing agents can effectively reduce the maximum surface temperature and the maximum heating rate of the battery.

Key words: electric vehicle, lithium-ion battery, thermal runaway, C6F12O, water mist