Panasonic Holdings Corporation

Panasonic Energy Co., Ltd.

Panasonic Intellectual Property Management Co., Ltd.

Sanyo Electric Co., Ltd.

Takamitsu Tashita

Takuya Shinomiya

Fumikazu Mizukoshi

Junichi Sugaya

Naoya Morisawa

Shimpei Yamagami

Syunsuke Natsumeda

Tsukasa Gejo

Takao Tsuda

The purpose of the present disclosure is to provide a nonaqueous electrolyte secondary battery which is provided with a negative electrode mixture layer that exhibits excellent electrolyte absorbing properties. A nonaqueous electrolyte secondary battery according to one embodiment of the present disclosure is characterized by being provided with a negative electrode having a negative electrode collector and a negative electrode mixture layer that is provided on the surface of the negative electrode collector, and is also characterized in that: the negative electrode mixture layer contains graphite particles A and graphite particles B, which serve as a negative electrode active material, and a rubber binder which serves as a binding agent; the graphite particles A have an internal void fraction of 5% or less; the graphite particles B have an internal void fraction of from 8% to 20%; if the negative electrode mixture layer is divided into two halves in the thickness direction, the outer surface-side half contains more graphite particles A than the negative electrode collector-side half; and from 90% to 100% of the all rubber binder contained in the negative electrode mixture layer is contained in the negative electrode collector-side half.

Nonaqueous electrolyte secondary battery

A non-aqueous electrolyte secondary cell comprising a negative electrode () having a negative electrode collector () and a negative electrode active material layer () provided on the negative electrode collector (). The negative electrode active material layer () contains graphite particles A and graphite particles B as negative electrode active materials. The graphite particles A have an internal void rate of 5% or less. The graphite particles B have an internal void rate of 8 to 20%. When the negative electrode active material layeris halved in the thickness direction, a regionon the half closer to the outer surface contains more graphite particles A than a regionon the half closer to the negative electrode collector.

Non-aqueous electrolyte secondary cell

A cylindrical battery, as one example according to an embodiment of the present disclosure, is provided with: an electrode body formed by spirally winding a positive electrode and a negative electrode with a separator interposed therebetween; and a bottomed cylindrical exterior can for accommodating the electrode body. The negative electrode has a negative-electrode core body and a negative-electrode mixture layer provided on a surface of the negative-electrode core body. An exposed area in which the surface of the negative-electrode core body is exposed is formed on an outer circumferential surface of the electrode body, and the exposed area is in contact with the inner surface of the exterior can. The negative-electrode mixture layer contains, as a negative-electrode active material, graphite particles having an internal porosity of 5% or less and a fracture strength of 25-55 MPa.

Cylindrical battery

The purpose of the present disclosure is to provide a non-aqueous electrolyte secondary battery having excellent low-temperature properties. A non-aqueous electrolyte secondary battery according to an aspect of the present disclosure comprises a negative electrode having: a negative electrode current collector; and a negative electrode active material layer disposed on the negative electrode current collector, wherein the negative electrode active material layer contains graphite particles A and graphite particles B as a negative electrode active material. The internal porosity of graphite particles A is 8-20%, and the internal porosity of graphite particles B is 5% or less. When the negative electrode active material layer is bisected in the thickness direction into a negative electrode current collector-side first half region and an outer surface-side second half region, the amount of graphite particles A in the second half region is greater than in the first half region.

Non-aqueous electrolyte secondary battery

The purpose of the present disclosure is to provide a non-aqueous secondary battery that is able to suppress a decrease in charge-discharge cycle characteristics. The non-aqueous electrolyte secondary battery that is a mode of the present disclosure comprises a negative electrode having a negative electrode active material layer, wherein the negative electrode active material layer contains a negative electrode active material that contains graphite particles, and an SBR component selected from at least one of a styrene-butadiene copolymer rubber and a modified product thereof, the internal porosity of the graphite particles is 1% to 5%, the porosity due to voids between particles of the negative electrode active material layer is 10% to 20%, and the content of the SBR component is 1.5 mass % to 3 mass % with respect to the mass of the negative electrode active material.

A non-aqueous electrolyte secondary battery capable of suppressing an increase in man-hour for a compression process in the production of a negative electrode and also suppressing a deterioration in charge/discharge cycle characteristics is provided. A non-aqueous electrolyte secondary battery according to one embodiment of the present disclosure is provided with a negative electrode having a negative electrode active material layer, wherein: the negative electrode active material layer includes graphite particles A and graphite particles B as a negative electrode active material; the internal porosity of the graphite particles A is 5% or less, and the internal porosity of the graphite particles B is 8-20%; and the mass ratio of the graphite particles A to the graphite particles B is 70:30 to 90:10.

Growing community of inventors

Tokushima, Japan

Takamitsu Tashita