NOVELTY - The battery comprises an electrode assembly (110) including a first electrode (111), a second electrode (112) and a separator (113) placed between the electrodes, a pouch (120) accommodating the electrode assembly and including a metal layer, and a vent formed on a side of the pouch by forming a trench in the metal layer. The battery further comprises electrode tabs electrically connected to the electrodes and protruding to the other side of the pouch, where the pouch has a pair of facing long sides and a pair of facing short sides connecting the long sides.    USE - The rechargeable battery is useful as a nickel-hydrogen battery.    ADVANTAGE - The vent can be ruptured, when the gas is generated in the pouch and the pouch swells due to an abnormal operation of the electrode assembly, thus releasing the gas in the pouch rapidly to the outside.    DETAILED DESCRIPTION - The battery comprises an electrode assembly (110) including a first electrode (111), a second electrode (112) and a separator (113) placed between the electrodes, a pouch (120) accommodating the electrode assembly and including a metal layer, and a vent formed on a side of the pouch by forming a trench in the metal layer. The battery further comprises electrode tabs electrically connected to the electrodes and protruding to the other side of the pouch, where the pouch has a pair of facing long sides and a pair of facing short sides connecting the long sides. The electrode tabs protrude one of the short sides, and the vent is formed to be close to the short side facing the short side from which the electrode tabs protrude. The pouch further includes a first pouch layer formed on a surface of the metal layer facing the electrode assembly, and a second pouch layer formed on the other surface of the metal layer. The vent is formed by forming trenches on the surfaces of the metal layer contacting the pouch layers. The first pouch layer is made of an insulating, thermally adhesive material. The vent is shaped of a diagonal line extending from the long side to the short side of the pouch, is shaped of an arc extending from the long side to the short side of the pouch and is shaped of a diagonal line extending towards an interconnection point where the long side and the short side of the pouch meet. The vent comprises a main vent portion shaped of a diagonal line extending from the long side to the short side of the pouch, and auxiliary vent portions extending from opposite ends of the main vent portion and formed to be parallel with the long and short sides of the pouch. The pouch includes a first pouch film having an accommodation groove in which the electrode assembly is accommodated, and a second pouch film covering the accommodation groove and coupled to the first pouch film, where the vent is formed in the accommodation groove of the first pouch film. The pouch films are connected to each other through one of the pair of short sides. A sealing portion is formed on the outer periphery of the accommodation groove of the first pouch film to be sealed to the second pouch film. Each tab includes an insulation member formed at contact portions between the electrode tabs and the sealing portion.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic perspective view of a rechargeable battery.    Electrode assembly (110)    First electrode (111)    Second electrode (112)    Separator (113)    Pouch. (120)