Suppression of thermal runaway induced by thermal abuse in large-capacity lithium-ion batteries with water mist

Thermal runaway (TR), as the most critical safety problem of lithium-ion batteries (LIBs), may cause considerable accident consequences, especially for large capacity LIBs, TR hazards should be multiplied. Therefore, effective TR mitigation strategies are needed. Water mist (WM), being widely considered as a clean and efficient fire suppression method, is employed for TR control in this work. TR evolution of the multi-cell large capacity LIBs induced by thermal abuse has been clearly demonstrated for the first time, the disaster characteristics of the LIB before TR are dominated by the successive gas production behaviors of the internal cells, but the battery ultimately triggers the TR as a whole. More than that, the critical signal is identified based on the battery disaster development and is successfully used for TR suppression. Then the reason for TR being suppressed is revealed by elucidating the overall and instantaneous cooling effects of the WM on LIBs. Moreover, it is found that the disaster of large capacity LIBs develops quickly, and 15 s is sufficient to make TR uncontrollable. Even so, the WM still exhibits excellent cooling ability, taking away over 65 % of the battery heat accumulation. The results provide the first comprehensive analysis of TR evolution and clarify the ability of WM in TR suppression of multi-cell LIBs.