My suggestion is 1st you use heat and then use a tool to scrape out the glue on the side by the metal microphone.

Then as others have mentioned, heat again and then apply pressure (1st time i did with fingers, 2nd was with a small glamp) to kind of make the sides sort of pop. Be gentle and slow but firm. that caused enough of a gap that i was able to get the metal tool in to open a bit, making room for a plastic tool to open it slowly.

I don't know how advisable it is, but i was able to skip this step. I couldn't get the cable out so i decided to try it. and i was able to get the battery out just fine. It was a bit more difficult, but imo much easier.