A battery pack of the present disclosure achieves sequential snap-fit engagement through a longer first positioning block at one end and a second positioning block at the other end matching with a first positioning hole and a second positioning hole in a battery compartment, and is combined with the elastic abutting force of an elastic arm to ensure stable mounting and easy disassembly; guide ribs on two opposite side walls of the battery compartment form an auxiliary support after the battery pack is mounted in place, effectively restricting the left and right swinging of the battery pack, and converting surface contact into line contact to reduce frictional resistance; a battery pack disassembly opening and an outer cover disassembly opening are matched with a first protrusion and a second protrusion, so that a user can open an outer cover of the battery compartment and pull up the battery pack without any tools.