The models with the oval bottom just have that cap pressed into the end with two small clips on the long side of the oval. Deforming the oval into a circle and using a small flat blade screwdriver to pry it out is usually all it takes.
I’ve successfully desoldered the battery for recharging before. We had one go so completely flat the wireless charging wouldn’t work. Putting the battery in an external charger brought it back to life. It was in service for another couple years till a drop in the brush end ruined it.
The models with the oval bottom just have that cap pressed into the end with two small clips on the long side of the oval. Deforming the oval into a circle and using a small flat blade screwdriver to pry it out is usually all it takes.
I’ve successfully desoldered the battery for recharging before. We had one go so completely flat the wireless charging wouldn’t work. Putting the battery in an external charger brought it back to life. It was in service for another couple years till a drop in the brush end ruined it.