Sanyo Electric Co., Ltd.

Prime Planet Energy & Solutions, Inc.

Tetsuya Okado

Masashi Muraoka

Tomoharu Arai

Toyoki Fujihara

Shingo Tode

Keisuke Minami

Shinichirou Yoshida

Hirofusa Tanaka

Takafumi Tsukagoshi

Kazutaka Mita

Atsushi Miyazaki

Kazuki Takeno

Shuji Ogawa

Mio Nosaka

In a method for producing a nonaqueous electrolyte secondary battery according to the present invention, a wound electrode body and a flat wound electrode body are formed by pressing. The flat wound electrode body and a cover member are connected to each other; a battery case and the cover member are integrated with each other; and a nonaqueous electrolyte solution is injected using a liquid injection port of the cover member, and the liquid injection port is sealed after the liquid injection, thereby forming a nonaqueous electrolyte secondary battery before inspection. Subsequently, the nonaqueous electrolyte secondary battery before inspection is pressed into a predetermined pressed state. A predetermined charge/discharge inspection is performed on the nonaqueous electrolyte secondary battery in the predetermined pressed state. If predetermined inspection specifications are satisfied in the predetermined charge/.discharge inspection, the nonaqueous electrolyte secondary battery is considered as a product that is ready for shipment.

Method for producing nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery

A nonaqueous electrolyte secondary battery includes an exterior package, an electrode assembly, and an electrolyte solution. The exterior package stores the electrode assembly and the electrolyte solution. The electrode assembly is shaped to have a flat shape. The electrode assembly includes a layered body. The layered body includes a first separator, a positive electrode plate, a second separator, and a negative electrode plate. The first separator, the positive electrode plate, the second separator, and the negative electrode plate are layered in this order. The electrode assembly is formed by spirally winding the layered body. Each of the first separator and the second separator has a proportional limit of less than or equal to 10.2 MPa. The proportional limit is measured in a compression test in a thickness direction of each of the first separator and the second separator.

Nonaqueous electrolyte secondary battery and battery pack

A nonaqueous electrolyte secondary battery includes an electrode assembly and an electrolyte solution. The electrode assembly is impregnated with at least part of the electrolyte solution. The electrode assembly includes a positive electrode, a negative electrode, and a separator. The separator separates the positive electrode and the negative electrode from each other. The negative electrode includes a negative electrode active material. The negative electrode active material includes graphite. The following relation of a formula (1) is satisfied: '1.60&#x2264;NPR/AAR&#x2264;2.55'. 'NPR' represents a ratio of a negative electrode charging capacity to a positive electrode charging capacity. &#x201c;AAR&#x201d; represents a ratio of an effective discharging capacity of the negative electrode to a total of a capacity corresponding to an amount of inactive lithium adhered to the negative electrode and the effective discharging capacity of the negative electrode.

Nonaqueous electrolyte secondary battery

A battery pack includes a plurality of prismatic secondary batteries with spacers each interposed therebetween. The prismatic secondary batteries each include a flat wound electrode body that is formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween; a prismatic outer body that houses the wound electrode body; and a sealing plate that seals an opening of the flat wound electrode body. The wound electrode body has a wound positive electrode core-exposed portion at one end portion and a wound negative electrode core-exposed portion at the other end portion. A positive electrode current collector is joined to the positive electrode core-exposed portion to form a positive electrode-joined portion, and a negative electrode current collector is joined to the negative electrode core-exposed portion to form a negative electrode-joined portion.

Battery pack

A nonaqueous electrolyte secondary battery including a positive electrode collector electrically connected to a positive electrode plate, a negative electrode collector electrically connected to a negative electrode plate. At least one of the collectors includes a first-side base portion disposed near the sealing plate, and a first-side lead portion connected to one end portion of the first-side base portion and extending towards an electrode body. The first-side lead portion includes a first-side power generating element joining portion joined to a lateral side of the electrode body, and a first-side inclined portion inclined with respect to a thickness direction of the electrode body from the first-side power generating element joining portion towards an outer side in the thickness direction. A total weight of the electrode body and nonaqueous electrolyte contained in the electrode body ranges from 200 g or more to 500 g or less.

A prismatic secondary battery includes a first current collector and a second current collector. The first current collector includes a first base disposed along a sealing plate. The second current collector includes a second base disposed along the sealing plate. A distance between an end portion of a wound electrode body facing the sealing plate and a surface of the first base facing the wound electrode body at an end portion of the first base on a central side in the longitudinal direction of the sealing plate is shorter than a distance between the end portion of the wound electrode body facing the sealing plate and a surface of the second base facing the wound electrode body at an end portion of the second base on the central side. An insulating buffer is disposed between the wound electrode body and the above surface of the first base.

Growing community of inventors

Hyogo, Japan

Tetsuya Okado