Patent ID: 7261972
Filing Date: 2007-08-28
Classification: H01M,Y02E,Y02P

Abstract:
1. A nonaqueous electrolyte secondary battery comprising: an electrode group having a positive electrode and a negative electrode wound flatly by way of an interposed separator, the electrode group including a spiral winding surface having a laminated structure wherein the positive electrode, the separator and the negative electrode are laminated; a positive electrode lead tab electrically connected to the positive electrode, and projecting from the spiral winding surface of the electrode group; a negative electrode lead tab electrically connected to the negative electrode, and projecting from the spiral winding surface; and a nonaqueous solvent, wherein the nonaqueous solvent contains cyclic carbonate including ethylene carbonate (EC) and propylene carbonate (PC), and sultone compound including a ring that has at least one double bond, the EC, PC and sultone compound are, supposing x (vol. %), y (vol. %), and z (vol. %) respectively, contained in the total volume of the nonaqueous solvent at the rate of 15≦x≦60, 35≦y≦85, and 0<z≦10, and a distance between the positive electode lead tab and the negative electrode lead tab is 6 mm to 18 mm.