I am having a similar issue to what was addressed here: https://www.googlenestcommunity.com/t5/Nest-Protect/Nest-Protect-batteries-burning-hot-amp-Nest-supp... and here: https://www.googlenestcommunity.com/t5/Nest-Protect/Issue-with-scalding-hot-battery-in-nest-protect/...
I was studying in my office, where one of my next protects resides, and was startled by a loud chirp. Nothing else in the room could have made a noise like that, so I checked my nest protect and as I was taking it off the ceiling, my app alerted me to an extremely low battery. Ah, that explains it I thought. I opened up the battery compartment to swap them and was greeted by the faint smell of what I can only describe as hot plastic/burning rubber. I pulled the batteries out and one of them was BURNING hot. Like boiling water hot - could barely touch it. I put fresh batteries in the device and it seems fine for now, I will be monitoring it very closely.
The hot battery remained hot for quite some time and I moved it outside using rubber tongs to cool off. I am concerned about how hot it got for sure. I have 7 nest protects and man, I really hope this doesn't turn into a widespread problem. I invested in these to protect my home from fires, not to potentially cause them.
I called Nest Support, they filed a case with "Nest Safety" and said they will be following up with me. Case number 3-6067000033096. I wanted to post the issue here as well, so that it's documented in the community, as it seems like an issue that is potentially widespread.
