Foreign matter defect battery and sudden spontaneous combustion

Many batteries of electric vehicles and energy storage power stations around the world experienced sudden spontaneous combustion accidents under normal use, and their historical operating data is generally normal. We find that the foreign matter mixed into the battery during the manufacturing process is one of the main culprits of the sudden spontaneous combustion accident. Through intentionally making defect batteries, aging experiments, and characterization analysis at different stages, the evolution mechanism of foreign matter defect in the battery is revealed. The self-induced internal-short-circuit fusing and sudden spontaneous combustion of the battery under non-abuse are all reproduced. Although the evolution of foreign matter defects is uncertain and sporadic, we still find some clues for the early warning of battery safety from the external characteristic data of the battery. The research results of this paper are helpful to understand the actual sudden spontaneous combustion mechanism of batteries and improve the safety of batteries and battery manufacturing. [Display omitted] •Evolution mechanism of foreign matter defect in the lithium-ion cell is revealed.•Sudden spontaneous combustion of lithium-ion cells under non-abuse is reproduced.•Self-induced internal-short-circuit fusing of lithium-ion cells is reproduced.•Early warning strategy for sudden spontaneous combustion of batteries is proposed.