Phonak Marvel and Paradise rechargeable battery type

Hearing Aid Batteries
3

It is a LIR7854/CP7854/ZeniPower Z23L and is a 7.8mmx5.4mm Lithium Ion cell with about 20mAh capacity.

Changing them is not an easy job at all:

https://forum.hearingtracker.com/t/insight-into-the-inside-of-the-hearing-aid/70911