Sanyo Electric Co., Ltd.

Hiroshi Maesono

Yohei Muroya

Shinichirou Yoshida

Hiroyuki Inoue

A valve body of a gas discharge valve includes a substantially annular main notch for opening the valve body and an auxillary notch provided in a region inside the main notch. The main notch and the auxillary notch are coupled to each other at least at one location. At a coupling portion between the main notch and the auxillary notch, the curvature of an inner corner of a bottom portion of the main notch is equal to or less than 0.05, and the curvature of an outer corner of the bottom portion is equal or greater than 0.05. Assuming that the thickness of the valve body at a portion thereof located in the opposite direction of the auxillary notch when viewed from the coupling portion is t1 and the thickness the valve body at a portion thereof located below the bottom portion of the main notch is t2, t2/t1≥0.16 is satisfied.

Gas discharge valve of battery and battery

A square secondary battery includes an electrode body including a positive electrode plate and a negative electrode plate, a square outer package housing the electrode body, a metal sealing plate sealing an opening of the square outer package, and a positive electrode collector electrically connected to the positive electrode plate and the sealing plate. The positive electrode collector includes a base portion disposed to oppose the sealing plate, and a lead portion extending from an edge portion of the base portion towards the electrode body. In a short direction of the sealing plate, a boundary between the base portion and the lead portion is positioned on a first side with respect to a center of the sealing plate, and a connection between the sealing plate and the base portion of the positive electrode collector is offset to a second side with respect to the center of the sealing plate.

Square secondary battery and method of manufacturing same

A secondary battery including an electrode body that includes a positive electrode plate and a negative electrode plate, an outer body that houses the electrode body, a metal sealing plate that seals an opening of the outer body, a positive electrode collector electrically connected to the positive electrode plate and the sealing plate, a negative electrode external terminal connected to the negative electrode plate through a negative electrode collector. In the secondary battery, a first projection and a second projection are formed on a surface of the sealing plate on a battery inner side, the positive electrode collector includes a first opening and a cut-out, the first projection is disposed in the first opening, the first projection and an edge portion of the first opening is welded and connected to each other, and the second projection is disposed in the cut-out.

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Hyogo, Japan

Hiroshi Maesono