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 (PCM) electrically connected to the electrode terminals 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 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 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 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 (PCM) electrically connected to the electrode terminals 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 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 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 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. <EOS>