Sony Corporation

Fumiko Hashimoto

Yuzuru Fukushima

Hiroshi Inoue

Akira Yamaguchi

Kumiko Takagi

Yasufumi Minato

Hiroyuki Suzuki

Satoshi Mizutani

Shinji Hatake

A battery including: a spirally wound electrode body in which a cathode having a cathode active material layer on a strip-shaped cathode current collector and an anode having an anode active material layer on a strip-shaped anode current collector are layered with a separator in between, and spirally wound in a planular state; and a lead joined to the cathode current collector or the anode current collector in a center portion of the spirally wound electrode body. An inner circumferential end of the cathode active material layer is provided in a region where the inner circumferential end does not overlap with the lead in a short axis direction of the spirally wound electrode body.

Secondary battery

A secondary battery capable of improving charge-discharge cycle characteristics in the case where an alloy material is used as an anode active material is provided. An exposed cathode region is disposed in an outer end portion of a cathode. The exposed cathode region includes an insulating protective member on at least one of an outer side and an inner side of the exposed cathode region in a position opposed to an outer end portion of an anode active material layer in one turn inside the outer end portion. In a cathode active material layer, a central angle between an outer end portion and a central end portion at the center of the spirally wound body is preferably within a range from 0&#xb0; to &#x2212;90&#xb0; inclusive from the central end portion in a winding direction.

Spirally wound secondary battery with uneven termination end portions

A battery capable of improving the energy density and cycle characteristics is provided. A cathode active material layer contains a complex oxide containing Li and Co as a cathode active material. An anode active material layer contains a CoSnC containing material containing Sn, Co, and C as an element, in which the content of C is from 16.8 wt % to 24.8 wt %, and the ratio of Co to the total of Sn and Co is from 30 wt % to 45 wt % as an anode active material. The surface density ratio of the cathode active material layer to the anode active material layer (surface density of the cathode active material layer/surface density of the anode active material layer) is from 2.77 to 3.90.

Battery

A battery that can secure the sufficient capacity, reduces deviation of the pressure distribution inside a spirally wound electrode body, and shows the superior charge and discharge characteristics is provided. The battery includes: a spirally wound electrode body in which a cathode having a cathode active material layer on a strip-shaped cathode current collector and an anode having an anode active material layer on a strip-shaped anode current collector are layered with a separator in between, and spirally wound in a planular state; and a lead jointed to the cathode current collector or the anode current collector in a center portion of the spirally wound electrode body. An inner circumferential end of the cathode active material layer is provided in a region where the inner circumferential end does not overlap with the lead in a short axis direction of the spirally wound electrode body.

Growing community of inventors

Fukushima, Japan

Fumiko Hashimoto