Don´t bend!
The battery has to be slided to the side carefully - like a piece of soap out of the shower tub - until it´s released by the bracket.

What majestyk said. You need to push the battery from the side opposite the open side and the battery will ride up over the edge of the holder and out from under the metal clip.

Thanks! Went well. 😀

In the case you accenditally bend the pin, you can use some aluminum foil folded multiple times to add some width between the battery and the pin and make a very good electrical contact. It works very well...