Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Seiichi Katou

Hideyuki Kumakiri

Katsuhisa Wadasaki

Takeharu Nakanose

Kouichi Nishihara

A secondary battery includes an electrode groupformed by winding a positive electrode plateand a negative electrode platewith a separatorinterposed therebetween. Each of the positive and negative electrode platesandincludes a current collectorand mixture layersandeach containing an active material and formed on the surface of the current collector. A plurality of trenchesare formed in the surfaces of the mixture layersandof at least one of the positive electrode plateand the negative electrode plate. The trencheshave curvature portions at side edgesand bottom centersthereof.

Secondary cell and its manufacturing method

A cylindrical guide sleeve has a larger-diameter portion formed at an upper portion thereof, a smaller-diameter portion formed at a lower portion thereof, and a tapered portion formed therebetween. The smaller-diameter portion has an inner diameter substantially identical with or slightly larger than an outer diameter of a cylindrical battery casing. A lower spindle supports a bottom surface of the cylindrical battery casing. An upper spindle pushes a seal plate downward along an inner surface of the cylindrical guide sleeve. In this case, the seal plate is inclined in a floating condition with respect to an axial direction of the cylindrical guide sleeve and connected via a lead to an electrode assembly accommodated in the cylindrical battery casing. A guide actuator shifts the cylindrical guide sleeve upward so as to surround the seal plate in the larger-diameter portion. An upper spindle actuator shifts the upper spindle downward to cause a spherical bottom surface of the upper spindle to push and guide the seal plate toward an upper opening of the cylindrical battery casing via the tapered portion.

Growing community of inventors

Osaka, Japan

Seiichi Katou