Patent ID: 7807292

Claim:
A secondary battery comprising: a strip-shaped cathode having a cathode collector coated with a cathode active material layer, but leaving end portions of the cathode collector uncoated; a strip-shaped anode having an anode collector coated with an anode active material layer, but leaving end portions of the anode collector uncoated; an electrolyte; a separator which contains the electrolyte; a lead; and a housing in which the cathode, anode separator electrolyte and lead are contained, wherein, the cathode and anode are spirally wound together about a central axis with the separator therebetween in a spirally wound electrode body the spirally wound body having a planular configuration with long and short axes which are perpendicular to each other and perpendicular to the central axis; each of the spirally wound cathode and anode has inner and outer uncoated circumferential end portions which are not coated by an active material layer, the lead is joined to the uncoated inner circumferential portion of the cathode current collector or the anode current collector at a center portion of the spirally wound electrode body, an inner circumferential end of the cathode active material layer is provided in a region where the inner circumferential end does not overlap with the lead along the short axis direction of the spirally wound electrode body, and the uncoated inner circumferential portion of the cathode or anode current collector joined to the lead extends at least one complete winding.