It's a statistical thing. Most phones don't explode their batteries. When you have a hundred or a thousand together, the chance that at least one has a battery explosion starts to reach concerning levels and you ask what you can do to avoid it.
replyIt's not really. I've had a test bench with smartphones at work with open smartphone test farm and about 50% of them cracked their cases open after a year or two. It is not a joke. It really happens. None of them actually got to the point of exploding but it didn't exactly look "safe". Of course I replaced them when this happened. Sometimes it took a while because they were on a stand, we only controlled them remotely so it would take me cleaning the stand or something to notice something was off.
replyStill, it served our support team really well during the pandemic. They could test wifi setups at the office with different android versions even when they were in a country that was on lockdown themselves.
OpenSTF was great: https://github.com/openstf
I think it's now been replaced by DeviceFarmer: https://github.com/DeviceFarmer/stf
I left my ~$1k OnePlus phone on the wireless charger for after ATT told me I couldn't use it and forced their spyware Samsung phone on me, The battery puffed up after about a year.
replyI carefully charged a Motorola G Power 2020 to a 60% SoC (which should be very safe) and left it in the car, unplugged, as a spare. It puffed up in about 6 months.
replyAn ignored Galaxy S7 puffed up while sitting on a shelf, unplugged, in a climate-controlled room.
Some other devices have been fine for far longer periods so it's not like I'm thinking it's endemic or anything (my Sony PSP is still working well-enough with its still-flat lipo cell from 2008), but it's certainly a concern.