Patent ID: 8277970
Filing Date: 2012-10-02
Classification: H01M,Y02E,Y02P

Abstract:
1. A secondary battery including an electrode assembly comprising a cathode/separator/anode structure mounted in a pouch-shaped battery case in a sealed state, the cathode comprising a cathode active material and the anode comprising an anode active material, wherein a residue portion, which is not sealed (non-sealing residue portion), is defined between a sealing portion of the battery case and the electrode assembly for collecting generated gas, the non-sealing residue portion comprising an outer circumferential end region comprising: (a) the electrode assembly mounted between upper and lower laminate sheets, at least one of which has a receiving part of a size corresponding to the electrode assembly; (b) the upper and lower laminate sheets having three sealed sides, including two sides where electrode terminals are disposed, among four sides of the upper and lower laminate sheets; (c) the non-sealing portion through which an electrolyte can be injected into the battery case; (d) thermally welded outer circumferential end region of the non-sealing portion, through which the electrolyte can be injected into the battery case, thereby forming a gas-receiving pocket of a width equivalent to 30 to 60% that of the non-sealing portion in the battery case, an outer end of the gas pocket suitable to be cut in order to: (e) the cut non-sealing portion thermally welded at a region where the cut non-sealing portion is spaced a predetermined width from the receiving part in which the non-sealing residue portion has a width equivalent to 10 to 40% that of the cut non-sealing portion; and (f) a solid electrolyte interface (SEI) film on the surface of the anode active material, the film having been formed as a result of initial charge and discharge of the secondary battery.