Blog

Thermal Runaway in Electric Vehicles

Electric car manufacturers have worked persistently in their pursuit to improve the range capacity and charging capabilities of lithium-ion batteries. In order to ensure the safety of their passengers, manufacturers must create an impregnatable active thermal management system to reduce the threat of thermal runaway. Thermal runaway is a reaction that occurs when a battery cell experiences an extreme rise in temperature at a rapid rate. Lithium-ion battery cells have a liquid electrolyte that is extremely flammable at high temperatures. The risk of thermal runaway begins when the battery cell reaches a temperature around 150°F. When the battery cell reaches 220°F, the liquid electrolyte ignites which breaks down the battery packs cathode, releasing oxygen and engulfing the battery pack to temperatures up to 750°F. This exothermic chain reaction can occur in less than a second.
 
Can Thermal Runaway Be Prevented?
 
The rapid rise in temperature leading to thermal runaway can be caused by a variety of reasons. Internal or external short circuits, overcharging the lithium-ion battery, and an abundance of currents during or after charging the battery cell have been linked to thermal runaway. To slow down or prevent the occurrence of thermal runaway Mica insulation can be utilized to prevent the temperatures outside of the battery pack from overheating or to slow down the thermal propagation once it begins. Axim Mica’s phlogopite sheets can withstand continuous temperatures up to 1292°F. Axim Mica’s sheets will slow down the thermal runaway process allowing passengers more time to safely exit their vehicle.