BATTERY BOX

A battery pack, including: a plurality of battery cells (1), where each of the plurality of battery cells (1) includes a top cover (11) and a case, the top cover (11) is hermetically connected on a top of the case, the case includes opposite first surfaces (12) and opposite second surfaces (13), and an area of each first surface (12) is larger than that of each second surface (13); and a lower housing, including a bottom plate (21) disposed at a bottom, side plates (22) disposed at sides, and an opening is disposed at an upper part, each of a pair of opposite side plates of the lower box is disposed with a reinforcing beam. At least one first surface (12) of the plurality of battery cells (1) is in contact with a side plate (22) of the lower housing or the reinforcing beam. The reinforcing beams disposed on a pair of opposite side plates (22) of the lower housing effectively increases strength of the side plates (22) of the lower housing. The battery cells (1) are arranged in the lower housing in rows, a heavy structure of module end plates is avoided, overall production cost of the battery pack is reduced, and the battery pack is made lightweight effectively.