Tl;Dr
As the battery rests in a deep discharge state, the electrolyte breaks down, turns into gas, and the battery poofs up.
I found this with my old PSP that I had stored away for years and pulled out one day for nostalgia purposes. Popped the battery cover off and it was all swollen like a balloon. It was quite a terrifying issue to have to deal with. Back in the old land of reddit, they even had a sub dedicated to this called r/spicypillows
Lol @ “spicy pillows” 😂
Spicy pillows
Special ravioli
It’s just getting filled up with love.
And when they are ready to share the love - they do clearly, without mixed signals! <3
The battery auto-ejects as to make the replacement of said battery easier.
Don’t do this, dangerous
When I was in school my phone battery expanded and would pop out of place. So I took the battery and put it on the floor and jumped on it to get it back into shape and put it back in my phone after.
I’m amazed it never exploded
Make a hole in it and you’ll see.