Patent ID: 7629078

Claim:
A cylindrical battery, comprising: a casing that is in a shape of a cylinder having a bottom, and has a short-diameter part near an opening thereof; an electrode assembly that is housed in the casing; and a sealing plate that seals the opening, wherein an insulating ring is inserted in a gap between the electrode assembly and the short-diameter part, the insulating ring including a main body, and at least three projections that are dispersively located and project outward from an outer edge of the main body in a diameter direction, and a distance between a design center point of the insulating ring and an outer edge of the main body is not longer than D/2 and a distance between the design center point and an outer edge of each of the projections is longer than D/2 and not longer than 102D/200, where D is an inside diameter of the casing measured within the gap.