Android phone turns off by itself

[AC Question]

So i have a galaxy j7 and me and my friends were playing then my phone just shuts off and can't turn it on. When i plugged my charger it turns on then i checked my phones cpu temp it is at 51° and at normal it is at 39-41° and i tried closing all the apps that were causing the high temp and cleared my cache partition but still it didn't work for me. It shuts down from 70% -68% battery life.

I need help.
Is it just my battery??

 

[BattleSwine]

Possibly, but most phone also have a thermal safety. Allow phone to completely cool down to room temperature, before charging or restarting it. I place my phone on marble counter for charging. It's petty effective at cooling the phone sometimes even lower than room temperature. High temperatures can cause damage to phone components. If you can keep the temperature down and phone still shuts down at the same battery % range it's most likely the battery. If it stays cool and makes it past that point looks more like thermal safety is engaging. Use safe mode to to disable and remove third party apps that maybe causing your thermal issues.