[Renate]

They adhesive for battery is usually overkill and hard to remove.

You can carefully drip in a bit of isopropyl alcohol to seep under the battery to loosen it. Try not to bend the battery when removing it.

Yes, I am advocating adding an inflammable liquid to an already dangerous entity so please be darn careful doing this. Maybe do it outside near a bucket of sand?

There is usually a flex cable under the battery. Disconnect both ends carefully so that a bit of pulling will do no damage to the flex cable. The power switch is usually held on with one screw.