Toyota Jidosha Kabushiki Kaisha

Fumihiko Ishiguro

Hiroyuki Nakayama

Akira Saito

Koshiro Yoneda

A secondary battery has a flat-shaped wound electrode body and a rectangular battery case housing the wound electrode body. In the wound electrode body, in at least any one of a positive electrode current collection foil laminated part and a negative electrode current collection foil laminated part, a positive electrode current collection foil exposed portion or a negative electrode current collection foil exposed portion is foil-bundled at a foil-bundling position and joined to a positive electrode current collection terminal or a negative electrode current collection terminal. At the foil-bundling position, the thickness A of the wound electrode body in the lamination direction and the shortest distance B to the foil-bundling position from the vertex of the R portion closest to the foil-bundling position among R portions of the wound electrode body satisfy, B≤(1/2) A.

Secondary battery including a wound electrode body with specified foil bundling

A sealed battery includes a case, an internal terminal, an external terminal, and an insulating holder. The internal terminal of the sealed battery includes a collector connected to an electrode body, a shaft part exposed outside the case, and a crimping part that is provided in an upper end portion of the shaft part. The crimping part is formed by pressurizing and deforming an upper end portion of the shaft part such that the crimping part extends along an upper surface of the external terminal. Then, the external terminal arranged outside the case is configured so that a linear expansion coefficient on a side of the upper surface and a linear expansion coefficient on a side of a bottom surface in contact with the insulating holder are different from each other.

Sealed battery

A sealed battery includes a case, an internal terminal, an external terminal, and an insulating holder. The internal terminal of the sealed battery includes a current collector connected to the electrode body, a shaft portion exposed outside the case, and a riveted portion that is provided on an end of the shaft portion outside of the case and is pressure-deformed so as to extend along an upper surface of the external terminal. The insulating holder includes a heat resistant portion formed of an insulating material having higher heat resistance than other regions of the insulating holder and the heat resistant portion is disposed in contact with the external terminal at least below a boundary between the riveted portion and the external terminal.

Provided is a cell in which the possibility of metallic foreign metal penetrating into an electrode assembly is reduced. The cell includes a rectangular cell case including a case main body and a lid member, an electrode assembly housed in the cell case, and an insulating film disposed between the cell case and the electrode assembly. The insulating film is in the form of a sheet, and is disposed between at least the electrode assembly and the bottom surface and the pair of long side surfaces of the cell case, and a pair of end portions of the insulating film in the height direction is located on the lid member side with respect to the electrode assembly. Incisions are provided in a thickness direction of the insulating film, and end portions with respect to the incisions constitute inclined surfaces which incline toward the electrode assembly side.

Growing community of inventors

Obu, Japan

Fumihiko Ishiguro