A battery module comprising 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 (11, 12) are not located, the module case is configured to have a frame structure open at one or more surfaces thereof, the module case comprising 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, the heat dissipation support member comprises a mount having a concavo-convex structure (510, 520) in which the battery cells are mounted, the heat dissipation support member is formed of a metal sheet, the heat dissipation support member has opposite side ends bent upward to surround a lower end of the battery cell stack and to at least partially surround opposite side surfaces of the battery cell stack, each of the battery cells is a plate-shaped battery cell having electrode terminals (11, 12) formed at one end or opposite ends thereof, at least one plate-shaped battery cell is mounted in a cell case to constitute a unit module, and the cell case comprises a cover having an inner surface directly contacting the plate-shaped battery cell and an outer surface directly contacting the heat dissipation support member of the module case, the cover being made of a metal material, the cell case comprises a cartridge in which the at least one plate-shaped battery cell is mounted in a state in which one surface or both surfaces of the at least one plate-shaped battery cell are exposed, and the cover is fastened to the cartridge such that the cover surrounds the at least one plate-shaped battery cell excluding electrode terminals (11, 12) of the at least one plate-shaped battery cell, characterized in that the cover is provided at opposite ends thereof with bent fastening parts bent downward or upward so as to be fastened to the cartridge, and the bent fastening parts of the cover and the cartridge are coupled to each other using an assembly fastening method, and coupling between the bent fastening parts of the cover and the cartridge using the assembly fastening method is achieved by fastening protrusions or fastening grooves formed at the bent fastening parts of the cover and fastening grooves or fastening protrusions formed at the cartridge, the fastening grooves or fastening protrusions of the cartridge corresponding to the fastening protrusions or fastening grooves of the bent fastening parts of the cover. 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 (11, 12) are not located, the module case is configured to have a frame structure open at one or more surfaces thereof, the module case comprising 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, the heat dissipation support member comprises a mount having a concavo-convex structure (510, 520) in which the battery cells are mounted, the heat dissipation support member is formed of a metal sheet, the heat dissipation support member has opposite side ends bent upward to surround a lower end of the battery cell stack and to at least partially surround opposite side surfaces of the battery cell stack, each of the battery cells is a plate-shaped battery cell having electrode terminals (11, 12) formed at one end or opposite ends thereof, at least one plate-shaped battery cell is mounted in a cell case to constitute a unit module, and the cell case comprises a cover having an inner surface directly contacting the plate-shaped battery cell and an outer surface directly contacting the heat dissipation support member of the module case, the cover being made of a metal material, the cell case comprises a cartridge in which the at least one plate-shaped battery cell is mounted in a state in which one surface or both surfaces of the at least one plate-shaped battery cell are exposed, and the cover is fastened to the cartridge such that the cover surrounds the at least one plate-shaped battery cell excluding electrode terminals (11, 12) of the at least one plate-shaped battery cell, characterized in that the cover is provided at opposite ends thereof with bent fastening parts bent downward or upward so as to be fastened to the cartridge, and the bent fastening parts of the cover and the cartridge are coupled to each other using an assembly fastening method, and coupling between the bent fastening parts of the cover and the cartridge using the assembly fastening method is achieved by fastening protrusions or fastening grooves formed at the bent fastening parts of the cover and fastening grooves or fastening protrusions formed at the cartridge, the fastening grooves or fastening protrusions of the cartridge corresponding to the fastening protrusions or fastening grooves of the bent fastening parts of the cover.