Patent ID: 7700222

Claim:
A sealed rechargeable battery comprising: an electrode group including a first electrode having a first collector provided with a first exposed section at one end thereof in the width direction, and a first active material layer disposed on the first collector, a second electrode having a second collector provided with a second exposed section at one end thereof in the width direction, and a second active material layer disposed on the second collector, and a separator interposed between the first electrode and the second electrode, the first electrode and the second electrode being wound together, about a winding axis, with the separator interposed therebetween so that the first exposed section and the second exposed section are exposed on axially opposite sides of the electrode group; an electrolyte, the electrode group being impregnated with the electrolyte; a first collecting plate welded to a first welding section formed of the first exposed section of the wound first electrode; a second collecting plate welded to a second welding section formed of the second exposed section of the wound second electrode; a case configured to store the electrode group and the electrolyte, the first collecting plate being coupled to an inner bottom face of the case; and a sealing plate, having a terminal, coupled to the second collecting plate, the sealing plate being applied to an opening of the case; wherein a plurality of radial slits are provided in at least one of the first welding section and second welding section; and wherein, in said at least one of the first welding section and second welding section having the slits, at least one of the first exposed section and second exposed section is folded outwardly in a direction from the winding axis toward an outer periphery of the electrode group, such that said at least one of the first exposed section and second exposed section forms a flat welding face.