A battery pack comprising: a plate-shaped battery cell having an anode terminal and a cathode terminal formed at one side thereof, said one side comprising a sealed surplus portion, and said battery cell being formed to have a planar quadrangular structure; a protection circuit module electrically connected to the electrode terminals (110, 120) of the battery cell to control operation of the battery pack, the PCM being loaded on the sealed surplus portion of the battery cell; and a pack case, wherein the pack case is applied to the sealed surplus portion of the battery cell, the PCM, and opposite sides (141, 142) of the battery cell in a thermally molten state and solidified, the pack case being configured to have a structure to cover the sealed surplus portion of the battery cell, the PCM, and the opposite sides (141, 142) of the battery cell in a state in which a top and a bottom of the battery cell are open, further comprising an insulating tape attached between the sealed surplus portion and the PCM, wherein the insulating tape is perferably a double-sided adhesive tape, wherein the insulating tape is attached to the sealed surplus portion of the battery cell, wherein the PCM is loaded on the sealed surplus portion of the battery cell due to the insulating tape, wherein the electrode terminals (110, 120) of the battery cell are bent such that the PCM is loaded on the sealed surplus portion of the battery cell, wherein the pack case is configured to have a structure including a total of three sides, such as a side to cover the upper end of the battery cell and sides to cover opposite sides of the battery cell, and wherein the pack case is formed in a 'Π' shape when viewed in plane. a plate-shaped battery cell having an anode terminal and a cathode terminal formed at one side thereof, said one side comprising a sealed surplus portion, and said battery cell being formed to have a planar quadrangular structure; a protection circuit module electrically connected to the electrode terminals (110, 120) of the battery cell to control operation of the battery pack, the PCM being loaded on the sealed surplus portion of the battery cell; and a pack case, wherein the pack case is applied to the sealed surplus portion of the battery cell, the PCM, and opposite sides (141, 142) of the battery cell in a thermally molten state and solidified, the pack case being configured to have a structure to cover the sealed surplus portion of the battery cell, the PCM, and the opposite sides (141, 142) of the battery cell in a state in which a top and a bottom of the battery cell are open, further comprising an insulating tape attached between the sealed surplus portion and the PCM, wherein the insulating tape is perferably a double-sided adhesive tape, wherein the insulating tape is attached to the sealed surplus portion of the battery cell, wherein the PCM is loaded on the sealed surplus portion of the battery cell due to the insulating tape, wherein the electrode terminals (110, 120) of the battery cell are bent such that the PCM is loaded on the sealed surplus portion of the battery cell, wherein the pack case is configured to have a structure including a total of three sides, such as a side to cover the upper end of the battery cell and sides to cover opposite sides of the battery cell, and wherein the pack case is formed in a 'Π' shape when viewed in plane.