Hi @nsluc ,
The tablet's battery may be failing and needs to be replaced. Even rechargeable batteries have a life span.
Here is a link to a [https://www.youtube.com/watch?v=XwyaX-M0yV0|video] which shows how to replace the battery in your tablet.
Search online for'' Samsung Galaxy Tab 2 7.0 battery'' to find suppliers of a replacement battery, that suit you best.
Hopefully this is of some help