Abstract: A nonaqueous electrolyte secondary battery includes: a positive electrode 4 including a positive electrode current collector and a positive electrode material mixture layer containing a positive electrode active material and a binder and provided on the positive electrode current collector; a negative electrode 5; a porous insulating layer 6 interposed between the positive electrode 4 and the negative electrode 5; and a nonaqueous electrolyte. The positive electrode current collector contains aluminium. The positive electrode current collector has an average crystal grain size of 1.0 ?m or more.

Abstract: Disclosed is a non-aqueous electrolyte secondary battery including: a spirally-wound electrode group including a continuous first electrode, a continuous second electrode, and a continuous separator interposed between the first electrode and the second electrode; and a non-aqueous electrolyte. The first electrode includes a sheet-like first current collector, and a first active material layer formed on a surface of the first current collector; and the second electrode includes a sheet-like second current collector, and a second active material layer formed on a surface of the second current collector. In the electrode group, the winding terminal end of the first electrode faces the second electrode on the further outer peripheral side, with the separator interposed therebetween. The facing site of the second electrode where the second electrode faces the winding terminal end of the first electrode is reinforced with a reinforcing component for supplementing the thickness of the second electrode.

Abstract: A non-aqueous electrolyte secondary battery comprising: an electrode group in which a long first electrode, a long second electrode, and a long separator disposed therebetween are wound spirally; and a non-aqueous electrolyte, is provided. The first electrode includes a sheet-like first current collector and a first active material layer disposed on a surface of the first current collector. The second electrode includes a sheet-like second current collector and a second active material layer disposed on a surface of the second current collector. An end portion of the first electrode on a winding-end side of the electrode group has a non-linear form and faces the second electrode placed on an outer circumferential side with the separator therebetween. The non-linear form is preferably a periodically continuous form, for example a waveform.

Abstract: A nonaqueous electrolyte secondary battery includes an electrode group (8) including a positive electrode (4) in which a positive electrode material mixture layer (4B) is provided on a positive electrode current collector (4A), a negative electrode (5) in which a negative electrode material mixture layer (5B) is provided on a negative electrode current collector (5A), and a porous insulating film (6). The positive electrode (4) and the negative electrode (5) are wound with the porous insulating layer (6) interposed. The positive electrode material mixture layer (4B) is provided on at least one of opposite surfaces of the positive electrode current collector (4A) located inside in a radial direction of the electrode group (8). The positive electrode material mixture layer (4B) has a porosity of 20% or lower.

Abstract: A nonaqueous electrolyte secondary battery includes: a positive electrode 4 including a positive electrode current collector and a positive electrode material mixture layer containing a positive electrode active material and a binder and provided on the positive electrode current collector; a negative electrode 5; a porous insulating layer 6 interposed between the positive electrode 4 and the negative electrode 5; and a nonaqueous electrolyte. The positive electrode current collector contains aluminium. The positive electrode current collector has an average crystal grain size of 1.0 ?m or more.

Abstract: A cylindrical non-aqueous electrolyte secondary battery of the invention includes: an approximately columnar electrode group having a strip-shaped positive electrode including a positive electrode material mixture layer formed on a positive electrode current collector and a strip-shaped negative electrode including a negative electrode material mixture layer formed on a negative electrode current collector that are spirally wound with a strip-shaped separator interposed therebetween; a non-aqueous electrolyte; a bottomed cylindrical battery case housing the electrode group and the non-aqueous electrolyte; and a negative electrode lead electrically connecting the negative electrode and the battery case.

Abstract: The present invention relates to a charging method of a lithium ion secondary battery including, as a positive electrode active material, a lithium-containing composite oxide containing nickel and cobalt and having a layered crystal structure. The charging method includes a first step of charging the battery at a first current of 0.5 to 0.7 It until the charge voltage of the battery reaches a first upper limit voltage of 3.8 to 4.0 V; a second step of charging the battery, upon completion of the first step, at a second current smaller than the first current until the charge voltage of the battery reaches a second upper limit voltage greater than the first upper limit voltage; and a third step of charging the battery, upon completion of the second step, at the second upper limit voltage. This provides a charging method of a lithium ion secondary battery, the method capable of achieving both a shortened charging time and an improvement in charge/discharge cycle life characteristics.

Abstract: A negative electrode for a lithium ion secondary battery comprising a material mixture layer comprising a carbonaceous material comprising a spherical natural graphite and a graphitized carbon fiber, wherein the material mixture layer has a carbon density of not less than 1.6 g/cm3; the spherical natural graphite has: (1) an interplanar spacing d002 between the (002) planes determined by an X-ray diffraction pattern of 0.3354 to 0.3357 nm, (2) a mean particle circularity of not less than 0.86, and (3) a mean particle size of 5 to 20 ?m; the graphitized carbon fiber has: (1) a mean fiber length of 20 to 200 ?m, and (2) a mean aspect ratio of 2 to 10; and the amount of the graphitized carbon fiber is 50 to 90% by weight of whole of the carbonaceous material.

Abstract: A negative electrode for a lithium ion secondary battery comprising a material mixture layer comprising a carbonaceous material comprising a spherical natural graphite and a graphitized carbon fiber, wherein the material mixture layer has a carbon density of not less than 1.6 g/cm3; the spherical natural graphite has: (1) an interplanar spacing d002 between the (002) planes determined by an X-ray diffraction pattern of 0.3354 to 0.3357 nm, (2) a mean particle circularity of not less than 0.86, and (3) a mean particle size of 5 to 20 &mgr;m; the graphitized carbon fiber has: (1) a mean fiber length of 20 to 200 &mgr;m, and (2) a mean aspect ratio of 2 to 10; and the amount of the graphitized carbon fiber is 50 to 90% by weight of whole of the carbonaceous material.