While you wait for answers, we may have found some information which could help you.
Click here for Replace Battery BatteriesBraun Shaver AC/DC Power plug broken, can I use a normal 12V adapter?
How do I take a Braun 5502 shaver apart?
Replacement battery for Braun 5502 shaver?
Braun 5550 Shaver Battery?
Batteries for Braun shaver 5614?
How to replace battery to a Braun silk epil lady shaver?