Effects of heat treatment and SOC on fire behaviors of lithium-ion batteries pack

Numerous lithium-ion battery fire accidents raise comprehensive safety concerns in modern society. In this paper, an experimental study was conducted to investigate fire behaviors of lithium-ion batteries under the effect of state of charge and heat treatments. The mass loss, heat release rate, and total heat released could be used as important evidence to explain differences and draw conclusions. The results showed that the fully charged lithium-ion batteries appear to be the most dangerous which presents the highest mass loss, peak heat release rate, and total heat released. The heat treatments can affect the heating condition and heat accumulation which lead to different ignition time and combustion behaviors. Horizontal 2 × 2 batteries have more fierce fire behaviors and more heat released than the vertical 2 × 2 batteries. The vertical 2 × 2 batteries exhibit explosive and violent ejection phenomena, and the mass loss is much higher than the horizontal configuration.