Why doesn't my phone charge when its battery gets too hot?

This is a built in safety device. Lithium batteries can 'self ignite' when they get too hot and they are extremely, almost impossible, to put out. Once your battery is fully cooled, it will charge again, unless it has been damaged by the heat. If damaged, it must be replaced. Do not leave your phone of the dash of a car or with the screen facing up in direct sunlight.