A method of manufacturing a battery pack comprising a battery cell having an electrode assembly received in a battery case, made of a laminate sheet comprising a resin layer and a metal layer, together with an electrolytic solution, the method comprising: (a) electrically connecting electrode terminals of the battery cell to electrode terminal connection parts of a protection circuit board (PCB, 400) having a protection circuit formed thereon; (b) coupling an upper case to an upper part of the PCB; (c) bending an upper sealed portion of the battery cell, at which the electrode terminals are located, and loading the PCB, to which the upper case has been coupled, on an upper end of the battery cell such that the PCB is parallel to an outer wall of an electrode assembly receiving part of the battery cell; (d) placing the upper case, the PCB, and the battery cell, which have been coupled to each other, in a mold (210, 220), which is provided in regions thereof corresponding to a peripheral edge of the battery cell with eight or more injection ports, through which a hot-melt resin is injected; (e) injecting a hot-melt resin through the injection ports to perform a hot-melt process, in which the hot-melt resin fills a space defined between: (i) the upper case, the PCB coupled with the upper case and loaded on the upper end of the battery cell, and the battery cell, and (ii) the mold; and (f) removing a resultant structure from the mold and wrapping the resultant structure with a label, wherein two or more injection ports are formed in an upper part of the mold (210, 220), at which the electrode terminals are located, wherein two or more injection ports are formed in a lower part of the mold (210, 220), wherein one injection port is formed in a middle of each side part of the mold (210, 220), and wherein a distance between the injection ports ranges from 10 mm to 15 mm. (a) electrically connecting electrode terminals of the battery cell to electrode terminal connection parts of a protection circuit board (PCB, 400) having a protection circuit formed thereon; (b) coupling an upper case to an upper part of the PCB; (c) bending an upper sealed portion of the battery cell, at which the electrode terminals are located, and loading the PCB, to which the upper case has been coupled, on an upper end of the battery cell such that the PCB is parallel to an outer wall of an electrode assembly receiving part of the battery cell; (d) placing the upper case, the PCB, and the battery cell, which have been coupled to each other, in a mold (210, 220), which is provided in regions thereof corresponding to a peripheral edge of the battery cell with eight or more injection ports, through which a hot-melt resin is injected; (e) injecting a hot-melt resin through the injection ports to perform a hot-melt process, in which the hot-melt resin fills a space defined between: (i) the upper case, the PCB coupled with the upper case and loaded on the upper end of the battery cell, and the battery cell, and (ii) the mold; and (i) the upper case, the PCB coupled with the upper case and loaded on the upper end of the battery cell, and the battery cell, and (ii) the mold; (f) removing a resultant structure from the mold and wrapping the resultant structure with a label, wherein two or more injection ports are formed in an upper part of the mold (210, 220), at which the electrode terminals are located, wherein two or more injection ports are formed in a lower part of the mold (210, 220), wherein one injection port is formed in a middle of each side part of the mold (210, 220), and wherein a distance between the injection ports ranges from 10 mm to 15 mm.