CCTV Footage another Mobile Phone Explode and Badly Burn Watch how Mobile Damage the Hand of Men in Shop. Too much heat in one area of the battery can lead to “thermal runaway”. This happens when an area of a battery can’t cool down quickly enough, resulting in a breakdown chain reaction that generates more and more heat. In other words, excess heat causes a reaction that accelerates the temperature increase. Eventually, this can lead to a fire or explosion.