Abstract: A sealed prismatic battery is provided. The battery includes a battery casing 4 having a prismatic cylindrical shape of body with a bottom part and an upper opening, and a lid 5 which fits in the upper opening of the battery casing. The opening of the casing body 4 and the lid 5 have laterally long shape in which the back-and-forth width dimension is smaller than the lateral length. The outer periphery of the lid 5 being welded to the periphery of the upper opening of the battery casing 4 to form a welded portion. The welded portion includes a pair of fragile parts 11 having low weld strength and formed at the ends of two long sides 10a and 10b of the welded portion which are parallel to each other, respectively, The battery is appropriately prevented from exploding and strength of battery is sufficiently provided against an impact caused by fall or the like.

Abstract: A sealed prismatic battery is provided. The battery includes a battery casing 4 having a prismatic cylindrical shape of body with a bottom part and an upper opening, and a lid 5 which fits in the upper opening of the battery casing. The opening of the casing body 4 and the lid 5 have laterally long shape in which the back-and-forth width dimension is smaller than the lateral length. The outer periphery of the lid 5 being welded to the periphery of the upper opening of the battery casing 4 to form a welded portion. The welded portion includes a pair of fragile parts 11 having low weld strength and formed at the ends of two long sides 10a and 10b of the welded portion which are parallel to each other, respectively, The battery is appropriately prevented from exploding and strength of battery is sufficiently provided against an impact caused by fall or the like.