Battery retainer

A battery retainer for retaining a battery comprising a positive electrode and a negative electrode, the battery retainer comprising

• a positive terminal for contacting the positive electrode of the battery,
• a negative terminal for contacting the negative electrode of the battery,
• a receiving chamber designed to be adapted to receive a battery and being open at a top, wherein the receiving chamber has a shape of a cylinder having an essentially circular cross section and is delimited by a cylindrical outer wall,
• a pivotable retaining arm located at a top of the receiving chamber and designed and arranged to hold a battery received in the receiving chamber therein, wherein the pivotable retaining arm has a curved shape corresponding to the curved shape of the outer wall and is radially offset from the outer wall towards the center of the battery chamber with respect to the circular cross section, and
• a spring element located at a bottom of the receiving chamber and designed and arranged to at least partly eject the battery received in the receiving chamber therefrom upon a pivotal movement of the pivotable retaining arm off the battery.