Disclosed herein is a battery module including chargeable and dischargeable battery cells mounted in a module case, wherein the battery cells are mounted in the module case in a state in which the battery cells are stacked in a lateral direction in which electrode terminals are not located, the module case is configured to have a frame structure open at one or more surfaces thereof, the module case including a receiving part to mount the battery cells, and a heat dissipation support member to dissipate heat from the battery cells through thermal conduction based on direct or indirect contact with the battery cells is mounted in the receiving part, in which the battery cells are mounted.