Fire 5 overheats when battery is plugged in, heatsink gets super hot when not on

[dr4ggy]

I'm not sure what happened but this fire 5 ran out of battery and shut down while it was in use. Now it won't charge or turn on with the power plug in. I can take the battery out and charge it with another fire 5, but when I plug the newly charged battery back in the heatsink that's circled in the attached picture gets super hot. I can even turn the tablet on and it'll boot in this state, but then it gets to hot and shuts down. If I unplug the battery and only plug in the usb it will not start or do anything. I don't know what that heatsink covers or what could be causing it to get super hot.