Disclosed herein is a secondary battery manufactured by mounting an electrode assembly having a cathode/separator/anode structure into a pouch-shaped battery case and thermally welding the electrode aDisclosed herein is a secondary battery manufactured by mounting an electrode assembly having a cathode/separator/anode structure into a pouch-shaped battery case and thermally welding the electrode assembly to the battery case, wherein a pair of insulative films are attached to opposite major surfaces of each electrode lead, to which electrode taps of the electrode assembly are electrically connessembly to the battery case, wherein a pair of insulative films are attached to opposite major surfaces of each electrode lead, to which electrode taps of the electrode assembly are electrically connected, at regions contacting an upper thermally-welded portion (upper sealed portion) of the pouch-shaped battery case, one of the insulative films (a, b), i.e., the insulative film (a), extends such tcted, at regions contacting an upper thermally-welded portion (upper sealed portion) of the pouch-shaped battery case, one of the insulative films (a, b), i.e., the insulative film (a), extends such that the lower end of the insulative film (a) supports a coupled region where the electrode taps are coupled to the electrode lead, and the overlapping length (L) between the insulative films (a, b) ishat the lower end of the insulative film (a) supports a coupled region where the electrode taps are coupled to the electrode lead, and the overlapping length (L) between the insulative films (a, b) is equal to or slightly greater than the height (H) of the upper sealed portion. The secondary battery according to the present invention has the effect of preventing the breakage of the electrode leadsequal to or slightly greater than the height (H) of the upper sealed portion. The secondary battery according to the present invention has the effect of preventing the breakage of the electrode leadsdue to the movement of the electrode assembly when external forces, such as small vibrations and dropping, are applied to the secondary battery, and, preferably, easily bending the electrode leads su due to the movement of the electrode assembly when external forces, such as small vibrations and dropping, are applied to the secondary battery, and, preferably, easily bending the electrode leads such that the PCM is mounted to the secondary battery.ch that the PCM is mounted to the secondary battery.