The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 04, 2017
Filed:
Aug. 19, 2015
Hitachi, Ltd., Tokyo, JP;
Naoki Kimura, Tokyo, JP;
Eiji Seki, Tokyo, JP;
HITACHI, LTD., Tokyo, JP;
Abstract
A lithium-ion secondary battery of the present invention contains: a laminated electrode group formed of a rectangular positive electrode; a rectangular negative electrode; and a separator. In such a laminated electrode group, the positive electrode includes a positive electrode current collector foil, and a positive electrode mixture layer containing a positive electrode active material, the negative electrode includes a negative electrode current collector foil, and a negative electrode mixture layer containing a negative electrode active material. The negative electrode active material includes a silicon-based material, and a carbonaceous material. A mass ratio of the silicon-based material and the carbonaceous material is 20:80 to 80:20. The silicon-based material is a Si alloy or SiO(0.5≦x≦1.5). The positive electrode and the negative electrode have a collection terminal protruding from a same side of the laminated electrode group. The negative electrode current collector foil is formed of any one of a stainless steel; a copper alloy containing a copper with a purity of 99.9% or more, and one or more kinds of elements selected from the group consisting of zirconium, silver and tin; and a copper with a purity of 99.99% or more. When a comparison are drawn between lengths of the positive electrode mixture layer and the negative electrode mixture layer in a direction where the collection terminal protrudes from the same side, the length of the positive electrode mixture layer is the length of the negative electrode mixture layer or longer. Thus, a short circuit in charging and discharging of the lithium-ion secondary battery can be suppressed.