Patent ID: 8192858
Filing Date: 2012-06-05
Classification: H01M,Y02E,Y02P,Y10T

Abstract:
1. An electrode plate group for a lithium ion secondary battery, said electrode plate group comprising a positive electrode and a negative electrode, said positive electrode including a positive-electrode current collector and positive-electrode mixture layers formed on the positive-electrode current collector, lateral end surfaces of the positive-electrode mixture layers forming a continuous plane with a lateral end surface of the positive-electrode current collector, said negative electrode including a negative-electrode current collector and negative-electrode mixture layers formed on the negative-electrode current collector, lateral end surfaces of the negative-electrode mixture layers forming a continuous plane with a lateral end surface of the negative-electrode current collector, said positive and negative electrode being stacked or wound with a separator interposed therebetween, wherein the negative electrode further includes a porous film continuously covering longitudinal surfaces of the negative-electrode mixture layers and the associated continuous plane, the porous film is formed directly on the associated continuous plane, the porous film contains a filler and a binder, the content of the filler in the porous film is higher than that of the binder in the porous film, a ratio of a weight of the filler to that of the binder is greater than or equal to 10, and the porous film is provided separately from the separator and disposed between the negative-electrode mixture layer and the separator.