In a study it should be fine, it's not something like stored in the garage rafters under the uninsulated tin roof with midday temps hitting 50 degrees.
Sad though, you must feel like I felt yesterday morning waking up to my phone screen shattered, wtf!?
I still don't know what I did because I put the phone in airplane mode before I put it down and I surely would have noticed it but sometimes I throw the phone onto the bed, near a metal torch, it may have landed on the torch by chance but even so the damage is hectic, the screen looks like a bullet hit it
Back to the battery, maybe try find someone with an aftermarket charger and try that.
I have a Dremel li-ion die grinder and the charger it came with is super particular about the battery, if I flatten the battery too far it will refuse to recharge it, I fortunately have another charger for a totally different device but also li-ion and the same same battery pack size(voltage) and I can use that with jumper leads and boost the Dremel enough that the original charger will detect it and finish the charge.
You can also use a variable power supply if you have access to one to charge the battery, it needs constant voltage and current controls. Just set the output to the pack voltage(it'll be stated on the battery) and 1A max current to be on the safe side. When charging li-ion to be safe monitor the temp of the battery, never let it get past slightly warm and you'll be fine.
