Patent ID: 7951487
Filing Date: 2011-05-31
Classification: H01M,Y02E,Y02P,Y10T

Abstract:
1. An electrode group for a nonaqueous battery comprising: a positive electrode and a negative electrode wound with a separator interposed therebetween, wherein the positive electrode includes a double-coated part which includes a positive electrode active material layer formed on each surface of a positive electrode current collector core; and a core exposed part which is located at a longitudinal center of the positive electrode current collector core, and does not include the positive electrode active material layer, a positive electrode current collector lead is connected to the core exposed part of the positive electrode, the negative electrode includes a double-coated part which includes a negative electrode active material layer and a porous protective film formed on each surface of a negative electrode current collector core; a core exposed part which is located at an end of the negative electrode current collector core, and does not include the negative electrode active material layer and a porous protective film; and a single-coated part which is located between the double-coated part and the core exposed part, and includes the negative electrode active material layer and a porous protective film formed only on one of the surfaces of the negative electrode current collector core, a plurality of grooves are formed in each surface of the double-coated part of the negative electrode, while the grooves are not formed in the single-coated part of the negative electrode, the grooves are formed in a surface of the porous protective film to extend in a surface of the active material layer, and a thickness of the porous protective film is smaller than a depth of the grooves, a negative electrode current collector lead is connected to the core exposed part of the negative electrode, and the negative electrode is wound in such a manner that the core exposed part of the negative electrode constitutes a last wound end.