A battery module (121a, 121b, 121c, 122a, 122b, 122c) having a plurality of battery cells electrically connected to each other, the battery module comprising: a plurality of cartridges (201, 202, 210), each of which comprises a frame member, to opposite sides of which battery cells are mounted, each of the cartridges (201, 202, 210) being provided at corners thereof with fastening parts (211, 211a, 211b, 211c, 211d), through which adjacent cartridges (201, 202, 210) are coupled to each other in order to constitute a cartridge assembly; a pair of end plates (141, 142) mounted to opposite side surfaces of the cartridge assembly so as to cover outermost cartridges (201, 202); and a busbar assembly mounted to one surface of the cartridge assembly, the busbar assembly comprising busbars for electrical connection between electrode terminals of the battery cells, each of the cartridges (201, 202, 210) is configured such that a cooling fin, with opposite surfaces of which the battery cells are in contact for thermal conduction, is mounted to a middle part of the cartridge (201, 202, 210), when viewed in vertical section, one end of the cooling fin being exposed outward from the cartridge (201, 202, 210), and gripping parts (216, 217a, 217b, 217c) for mounting the battery cells in position are formed on an inner surface of the frame member of the cartridge (201, 202, 210), wherein the frame member of each of the cartridges (201, 202, 210) is provided with an outer wall, which is formed along an outer edge of the frame member so as to extend upward and downward from the cooling fin, when viewed in vertical section, in order to cover the battery cells mounted to the opposite sides of the frame member, in which the outer wall of the frame member has a height corresponding to a height of each of the battery cells, the cooling fin is integrally formed with the frame member by insert molding, in which the cooling fin is made of a metal material, an inorganic material exhibiting high thermal conductivity, or a carbon material, the cooling fin is formed in a plate shape, and one end of the cooling fin, configured to extend outward for heat conduction, is configured to have a T-shaped structure so as to correspond to a shape of an outer surface of the frame member, when viewed in vertical section. a plurality of cartridges (201, 202, 210), each of which comprises a frame member, to opposite sides of which battery cells are mounted, each of the cartridges (201, 202, 210) being provided at corners thereof with fastening parts (211, 211a, 211b, 211c, 211d), through which adjacent cartridges (201, 202, 210) are coupled to each other in order to constitute a cartridge assembly; a pair of end plates (141, 142) mounted to opposite side surfaces of the cartridge assembly so as to cover outermost cartridges (201, 202); and a busbar assembly mounted to one surface of the cartridge assembly, the busbar assembly comprising busbars for electrical connection between electrode terminals of the battery cells, each of the cartridges (201, 202, 210) is configured such that a cooling fin, with opposite surfaces of which the battery cells are in contact for thermal conduction, is mounted to a middle part of the cartridge (201, 202, 210), when viewed in vertical section, one end of the cooling fin being exposed outward from the cartridge (201, 202, 210), and gripping parts (216, 217a, 217b, 217c) for mounting the battery cells in position are formed on an inner surface of the frame member of the cartridge (201, 202, 210), wherein the frame member of each of the cartridges (201, 202, 210) is provided with an outer wall, which is formed along an outer edge of the frame member so as to extend upward and downward from the cooling fin, when viewed in vertical section, in order to cover the battery cells mounted to the opposite sides of the frame member, in which the outer wall of the frame member has a height corresponding to a height of each of the battery cells, the cooling fin is integrally formed with the frame member by insert molding, in which the cooling fin is made of a metal material, an inorganic material exhibiting high thermal conductivity, or a carbon material, the cooling fin is formed in a plate shape, and one end of the cooling fin, configured to extend outward for heat conduction, is configured to have a T-shaped structure so as to correspond to a shape of an outer surface of the frame member, when viewed in vertical section.