Used a thin metal pry.

Nothing special, warm it and twist it until open by your hands. I know it’s hard, but be careful not to damage the parts.

I did not take apart it. However, from another source, I can inform you that the battery is LIR ZJ1254H 3.85V, which was made by Zijing technology. I will update a picture.

The Power IC is not 338S00267-A0, It is 338S00466-A0