A rechargeable battery module may include: a plurality of unit cells arranged in a first direction and electrically coupled via a bus bar, including a pair of outermost unit cells at opposite ends of the first direction; an end plate supporting the outermost unit cells; side plates at opposite ends of a second direction to support side surfaces of the unit cells; a support member supporting the unit cells at a lower end of a third direction; and welding bushes extended in the third direction at opposite ends of the end plate in the second direction and opposite ends of the side plates in the first direction. Each welding bush may include a cylinder member to which the end plate and one of the side plates are welded, and a cap member combined with at least one of opposite ends of the cylinder member.