This guide does not show the disassemble of the clearomizer (highlighted in the picture), as in more recent versions it is monolithic and can't be disassembled, and focuses on the cigarette body.

Unscrew the clearomizer, rotating it counterclockwise.

Remove the four screws holding the plastic covers to the metal frame:

Two Torx T4 screws on the top of the cigarette body, near the clearomizer plug

Two Torx T4 screws on the bottom of the cigarette body, near the USB port

Remove the bottom lid with a plastic spudger

Remove the top plastic lid with a plastic spudger. If it is stuck, due to debris, mount the clearomizer lower part and use it to pull the top cover.

Time to remove the front panel:

Insert a plastic spudger in the top part and start lifting it

Continue removing the front plate with a plastic opening pick

The frontal button should fall outside, as it is only laid inside the specific hole, not glued. If it is stuck, use a pair of ESD tweezers to remove it.

Extract the board and the battery, using a tweezer to pull the top of the board and/or pushing gently the lower part of the battery, with a round plastic spudger.

The battery is protected by three foam pads, the side one is glued both to the battery and to the board

The battery is a 14500 lithium battery. This one in particular is made by EVE, nominally it has a 3.7V voltage, has a 900 Mah capacity and can supply 3.33 Wh.