Why is my Tablet's battery draining when charging it and why it keeps turning off by itself whenever

[AC Question]

Sometimes it will turn off.
So it turn off like POP, and it is off.
All the reason I was thinking about is [ maybe when it keeps turning off by itself and I keep punching it causing the things inside my tablet damage? ] So when the day it keeps started happen again I started charging and using it. And this might be causing the battery damage. So does that means it keeps draining?