When an internal or external short circuit occurs in a lithium-ion battery, the battery releases a large amount of heat in a short period of time, and the temperature rises sharply, resulting in thermal runaway. The flammable liquid electrolyte is ignited at high temperatures, causing the battery to catch fire. Through thermal diffusion, a single thermally runaway battery causes thermal runaway of adjacent batteries through thermal conduction and flame, resulting in thermal runaway of the entire battery module/battery pack, resulting in a fire and explosion event.
Traditional battery modules use PP, ABS, PVC and other flame-retardant plastic separators to separate the single cells from each other, which does not play a role in thermal isolation protection, and also easily causes problems such as dissolution and ignition of the separator due to excessive battery temperature. When the battery is in a combustion accident, a large amount of toxic gas is generated, which directly endangers the respiratory system and nervous system of the passengers, making it difficult for the passengers to escape, and seriously endangering the lives and property of the people.
Silica aerogel is a porous solid material whose dispersion medium is gas. It has the characteristics of low thermal conductivity, good thermal insulation effect, Class A fire resistance, and light weight. In recent years, aerogel materials for power battery thermal insulation materials have begun to be used in the field of power battery fire protection and thermal insulation. It is considered to be a thermal insulation material that can be applied to the power battery of new energy vehicles and the thin thermal insulation material of power battery. In the case of thermal runaway of the battery cell, it can effectively inhibit thermal diffusion. On the other hand, it can effectively reduce the performance degradation of the battery in low temperature environment, and save more space for the limited battery pack.
