A battery module including a plurality of sub battery modules stacked together, each sub battery module comprising a plurality of battery cells, each of the battery cells having terminals and a vent portion on a first side of the sub battery modules; a pair of end plates, one of the ends plates located at each end of the battery module; a top plate on the first side of the sub battery modules; and a controller configured to control the battery cells for each of the sub battery modules, wherein each of the sub battery modules has an individual degassing region controlled by the controller.