Question about Metabo KB 18 BL

No, only with batteries from the Cordless Alliance (CAS).

Unfortunately, the refrigerator is not compatible with Bosch batteries.

A rechargeable battery system should actually have the advantage of being compatible with other manufacturers.
Metabo started this quite early on and Bosch unfortunately later launched its own system instead of joining the existing one.

See also here:
https://werkzeug-insider.de/ampshare-v...
https://www.econo.de/aktuelles...

No, because Bosch is not part of the CAS battery system...!

Unfortunately, I am not familiar with this and therefore cannot give a helpful answer. I also don't have a Bosch battery to test this for you.