As consumers demand higher range for electric vehicles and the energy density of lithium-ion batteries continues to improve, materials with high energy density may have lower thermal stability, leading to frequent safety incidents involving thermal runaway in power batteries. Thermal runaway in power batteries refers to the phenomenon where a single cell within the battery pack undergoes localised severe heating, which induces a chain reaction causing uncontrollable temperature rise in the battery. It is usually caused by external high temperatures, overcharging, over-discharging, puncture, short circuits, or intense collisions.
Currently, new energy vehicle manufacturers mainly adopt two methods of protection: active and passive. Active protection involves actively adjusting the internal temperature of the battery through methods such as air, liquid, or refrigerant cooling; passive protection primarily involves physically isolating the battery cells, modules, and packs using various flame-retardant insulating materials. Common types include mica materials, aerogel, flame-retardant foam, ceramicized silicone rubber, etc.
