Patent ID: 7776474

Claim:
A non-aqueous electrolyte secondary battery comprising an electrode group in which a positive electrode and a negative electrode are spirally wound with a separator interposed therebetween, said positive electrode comprising a positive electrode active material and a binder, said positive electrode active material comprising a mixture composed of two different particulate substances having different average particle sizes, said two different particulate substances each comprising a lithium composite metal oxide containing nickel as an essential element, said binder comprising fluorocarbon resin and particulate rubber particles, and said fluorocarbon resin comprising at least a vinylidene fluoride unit, wherein the amount of said rubber particles per 100 parts by weight of said fluorocarbon resin is 5 to 25 parts by weight, said mixture composed of two different particulate substances comprises a particulate substance A and a particulate substance B, and a ratio: D A /D B of the average particle size of said particulate substance A (D A ) to the average particle size of said particulate substance B (D B ) is 1.5 to 7, the weight percentage of said particulate substance A relative to said mixture composed of two different particulate substances is 50% to 80%, and the amount of said fluorocarbon resin is 1 to 3 parts by weight relative to 100 parts by weight of said positive electrode active material.