Patent attributes
A battery pack includes terminals (33) and a lock hook (37b). The terminals (33) are fastened onto a circuit board (74) and connected to rechargeable batteries (39). The terminals are exposed externally of a casing (31). The hook (37b) protrudes from a surface of the casing (31), and holds the battery pack on a charger (100). A hook opening window (24) is open in one of the surfaces of the casing. The hook (37b) can protrude from the surface of the casing (31). A drain hole (28) is open in another surface of the casing. A partition rib (25) is arranged between a path and an electronic circuit. The path is separated from the circuit. The path extends inside the casing (31) from the window (24). The circuit is mounted on the board (74). The window (24) communicates with the hole (28) through the path.