Open the battery compartment of the Shaver Part begins with cutting the outer wrapping of silicone along the red line with a knife.

After removing the silicone layer you will see the internal battery compartment structure, next you just need to use a screwdriver to press down the metal part inside the red circle to remove the battery compartment smoothly.

It took me a long time to disassemble the razor section, which appears to have a molded case and was designed with the intention of never opening it again.