Battery pack, battery box and working machine

The utility model relates to the technical field of batteries, and provides a battery pack, a battery box and an operation machine. The battery pack comprises a box body, a containing groove extending in the thickness direction of the battery pack is formed in the side wall of the box body and used for allowing a connecting plate to stretch in, the width of a groove opening of the containing groove is smaller than that of the groove bottom of the containing groove, and a connecting hole used for being connected with the connecting plate is formed in the groove bottom of the containing groove. According to the battery pack provided by the utility model, the accommodating groove into which the connecting plate extends is formed in the side wall of the box body, and the width of the groove opening of the accommodating groove is smaller than that of the groove bottom. Therefore, after the connecting plates are arranged in the accommodating grooves of the two adjacent battery packs, the connecting plates cannot be