Remove the battery and its film.

During reassembly:

Never reuse a deformed or damaged battery, as it's a potential safety hazard. Replace it with a new battery.

Use a spudger and tweezers to peel up and remove the two pieces of battery adhesive.

Apply the new adhesive to the frame and remove the plastic liners.

Firmly press the battery into its recess so the cable is on the top edge and the three tabs are on the left edge.