Sanyo Electric Co., Ltd.

Tomokazu Yamanaka

Yasuhiro Yamauchi

Yohei Muroya

Eiji Okutani

Hiroyuki Inoue

Hiroshi Takabayashi

Shinichirou Yoshida

Satoshi Yoshida

Takuya Yamawaki

Yoshikumi Miyamoto

Takuya Morimoto

Atsushi Obayashi

Ryuji Oshita

Kuroudo Hayakawa

Ryuhei Kai

A positive electrode terminal is inserted into a current-collector through hole formed, in a positive electrode current collector and riveted in a spot-faced hole formed in the positive electrode current collector. A protrusion is formed on a bottom surface of the spot-faced hole so as to extend around the current-collector through hole, and a riveted portion of the positive electrode terminal covers the protrusion. The riveted portion of the positive electrode terminal is weld-connected to an edge of the spot-faced hole.

Secondary battery

A secondary battery production method is provided, with which deformation of a current collector is reduced. The method produces a secondary battery including: an electrode assembly having positive and negative electrode plates; and a positive electrode current collector. The positive electrode plate includes a positive electrode core and a positive electrode active material layer, and the electrode assembly includes a positive electrode core-stacked portion. The method includes: an electrode assembly production step of producing the electrode assembly; and an ultrasonic bonding step of ultrasonically bonding the positive electrode current collector to the positive electrode core-stacked portion. The positive electrode current collector has a thin-walled portion. In the ultrasonic bonding step, the thin-walled portion and the positive electrode core-stacked portion are sandwiched between a horn and an anvil, and the thin-walled portion and the positive electrode core-stacked portion are ultrasonically bonded together.

Method for producing secondary battery

A method of manufacturing a secondary battery including a negative electrode collector connected to a layered negative electrode core body exposed portion by welding, the method including a first step of disposing a core body connection of the negative electrode collector on an outer surface side of a layered negative electrode core body exposed portion so that a recess in the core body connection opposes the layered negative electrode core body exposed portion, a second step of pressing, with a pressing member, a portion in the core body connection where the recess is formed, forming a deformed portion, and contacting the deformed portion to the layered negative electrode core body exposed portion, and a third step of abutting an electrode for resistance welding against the negative electrode collector and resistance welding the negative electrode collector and the layered negative electrode core body exposed portion to each other.

Method of manufacturing secondary battery

A prismatic secondary battery includes an electrode assembly, a casing having an opening, a sealing plate sealing the opening, a terminal connected to an electrode that constitutes the electrode assembly, and a current collector connected to the electrode. The current collector has a base portion located along the sealing plate and a lead portion extending from an end portion of the base portion toward a bottom of the casing. The base portion is welded to the terminal. The lead portion is connected to a substrate exposure portion of the electrode and has a fusible portion that is fusible by an excessive current and that has a smallest cross section compared to the remaining portion. The fusible portion has a cross section equal to or smaller than 92% of a cross section of the base portion that passes through an end portion of a weld-connection portion closer to the lead portion.

Prismatic secondary battery

Provided is a sealed battery that can offer excellent battery performances by having its electrode terminal and a current collector securely welded to each other, and its manufacturing method. The sealed battery is formed by hermetically sealing a casing storing an electrode assembly and the current collector, wherein: the electrode assembly formed by layering positive and negative electrode plates with a separator sandwiched therebetween is electrically connected to the current collector; and a shaft portion of the electrode terminal penetrates through the current collector. A part of the electrode terminal projecting out from a pass-through of the current collector is a (conical) frustum-shaped portion whose bottom base is in contact with the current collector. The frustum-shaped portion is pressed against the current collector, and the frustum-shaped portion and the current collector are welded together in at least one area on a perimeter of the bottom base of the frustum-shaped portion.

Sealed battery with electrode terminal welded to current collector, and manufacturing method for the same

A hermetic cell excellent in weld strength is provided. The hermetic cell includes an can having an opening and a seal for sealing the opening of the can. A portion of engagement of the seal with the opening of the can is welded with a high energy beam, thereby hermetically sealing the can. At least one portion of a melt mark resulting from the high energy beam welding has a top surface having a lowermost point lower in a direction of a bottom of the can than a lowermost point of a top surface of an adjacent portion of the melt mark. The at least one portion of the melt mark has a bottom surface having a lowermost point lower in the direction of the bottom of the can than an lowermost point of a bottom surface of the adjacent portion of the melt mark.

Hermetic cell and method for producing same

A method for producing a secondary cell having a flat wound electrode body that inhibits the bending of the electrode board caused by charging and discharging and inhibits resulting swelling of the cell and deterioration of cycle characteristics is provided. The method has the steps of: winding, with a winding core, a positive electrode board, a negative electrode board, and a separator provided between the positive and negative electrode boards, and fixing the winding end, thereby preparing an approximately cylindrical electrode body; after the step of preparing the electrode body, deforming the electrode body into a shape with an approximately oval cross section by pressing the approximately cylindrical electrode body from a direction perpendicular to the winding axis, and rotating the deformed electrode body in the winding direction, thereby relaxing the winding state; and after the relaxation steps, pressing the electrode body into the flat wound electrode body.

Method for producing a secondary cell having flat wound electrode body

This invention aims to provide a prismatic sealed secondary battery which is capable of ensuring a high battery capacity and suppressing the case swelling and which achieves high quality in appearance at low cost, and the method for manufacturing the same. To achieve the above objectives, the prismatic sealed secondary battery of the present invention has a structure in which an open end of the case that houses an electrode assembly therein is sealed by a sealing cap. On the main plane of the case, linear heat strain signatures are created. Additionally, depressions are formed along the heat strain signatures that are a principal cause of the depressions. On the case, within an area where the heat strain signatures have been created, a portion composed of a recrystallized structure is formed. This portion is, on cross section, fanned out inwardly the case plate from the center of linewidth of each heat strain signature.

Growing community of inventors

Hyogo, Japan

Tomokazu Yamanaka