What is thermal runaway?

Thermal runaway is a cycle in which excessive heat keeps creating more heat and is the major risk associated with lithium ion battery technology. It can be caused by cell defects, mechanical failures/damage or over voltage. Any of these occurrences will lead to high temperatures, gas build-up and potential explosive rupture of the battery cell, resulting in fire and/or explosion. Thermal runaway can also spread from one cell to another, causing additional damage.

Lithium ion batteries are extremely sensitive to mechanical damage and electrical surges, which can result in an internal short circuit which in turn leads to battery heating, explosion and fire. The loss of an individual battery can rapidly cause issues in surrounding batteries, resulting in large scale fires.