A battery module comprising: a battery cell array comprising two or more stacked battery cells, each of which is configured to have a structure in which an electrode assembly, comprising a cathode, an anode, and a separator disposed between the cathode and the anode, is received in a battery case together with an electrolyte in a sealed state; and fixing members, each of which is integrally coupled to a portion or the entirety of an outer edge of a corresponding one of the battery cells, each of the fixing members being provided with an assembly type coupling structure, by which the fixing members are coupled to each other such that the battery cell array forms a stable stack structure, a portion or the entirety of the outer edge of each of the battery cells and a corresponding one of the fixing members are integrally coupled to each other by insert injection molding, the assembly type coupling structure comprises a combination of a fastening member formed at one side of each of the fixing members and a fastening groove formed at the other side of each of the fixing members such that the fastening groove corresponds to the fastening member, the fastening member is formed at a top or a bottom of each of the fixing members, and the fastening groove is formed at the bottom or the top of each of the fixing members on a position corresponding to the fastening member, characterized in that the fastening member is formed in the shape of a cylinder protruding from one side of each of the fixing members and comprises a hook tapered along an outer circumference of an upper end of the cylinder, and in that the fastening groove is formed at the other side of each of the fixing members opposite to the fastening member in a cylindrically depressed shape and is provided at an inner circumference thereof with a catching protrusion, to which the hook of the fastening member is fastened. a battery cell array comprising two or more stacked battery cells, each of which is configured to have a structure in which an electrode assembly, comprising a cathode, an anode, and a separator disposed between the cathode and the anode, is received in a battery case together with an electrolyte in a sealed state; and fixing members, each of which is integrally coupled to a portion or the entirety of an outer edge of a corresponding one of the battery cells, each of the fixing members being provided with an assembly type coupling structure, by which the fixing members are coupled to each other such that the battery cell array forms a stable stack structure, a portion or the entirety of the outer edge of each of the battery cells and a corresponding one of the fixing members are integrally coupled to each other by insert injection molding, the assembly type coupling structure comprises a combination of a fastening member formed at one side of each of the fixing members and a fastening groove formed at the other side of each of the fixing members such that the fastening groove corresponds to the fastening member, the fastening member is formed at a top or a bottom of each of the fixing members, and the fastening groove is formed at the bottom or the top of each of the fixing members on a position corresponding to the fastening member, characterized in that the fastening member is formed in the shape of a cylinder protruding from one side of each of the fixing members and comprises a hook tapered along an outer circumference of an upper end of the cylinder, and in that the fastening groove is formed at the other side of each of the fixing members opposite to the fastening member in a cylindrically depressed shape and is provided at an inner circumference thereof with a catching protrusion, to which the hook of the fastening member is fastened.