Patent ID: 11962011
Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 0:
1. A nonaqueous electrolyte secondary battery comprising a coiled electrode assembly in which a positive electrode and a negative electrode are coiled with a separator interposed therebetween,
wherein the negative electrode includes a negative electrode current collector, a first negative electrode mixture layer formed on a first surface of the negative electrode current collector, the first surface facing an outside of the electrode assembly, and a second negative electrode mixture layer formed on a second surface of the negative electrode current collector, the second surface facing an inside of the electrode assembly,
the first negative electrode mixture layer contains a cellulose binder formed of at least one of carboxymethyl cellulose and a salt thereof and a rubber binder formed of at least one of styrene-butadiene rubber and a modified form thereof,
a content of the cellulose binder is, in a thickness direction of the first negative electrode mixture layer, larger near a surface of the mixture layer than near the negative electrode current collector,
a content of the rubber binder is, in the thickness direction of the first negative electrode mixture layer, larger near the negative electrode current collector than near the surface of the mixture layer, and
when the first negative electrode mixture layer is divided in half at a center in the thickness direction thereof, a content proportion of the cellulose binder present in a portion positioned near the surface of the mixture layer is 51% by mass to 70% by mass with respect to a total mass of the cellulose binder contained throughout the mixture layer.