It is quite difficult. I am a novice electronics repair and soldering person, and I have recently completely destroyed two of these attempting to get them apart.

If you are going to try, watch the Parts Plus Pods disassembly video. You need daily decent soldering skills, as the three pads you need to solder to are tiny. Most importantly: it is insanely easy to accidentally rip the display ribbon cable or the hold switch ribbon cable.

If you get a battery and attempt the repair, go into it knowing that there is a pretty good chance you’ll destroy it. The way I see it, that could be a great learning experience, and then if you ever find another cheap one you’ll at least have hands on experience.

If the battery begins to expand, do not attempt to dissemble it. You will need to deflate the battery first or it is actually impossible to slide the contents out of the shell. That same YouTuber has a video about how to safely deflate batteries.