Patent ID: 8329334
Filing Date: 2012-12-11
Classification: H01M,Y02E,Y02P,Y02T

Abstract:
1. A lithium secondary battery comprising: a battery can having a bottom, a side wall, and an open top; an electrode assembly; a non-aqueous electrolyte; and a sealing plate covering the open top of said battery can that accommodates said electrode assembly and said electrolyte, wherein: said electrode assembly comprises a strip-like positive electrode and a strip-like negative electrode that are wound together with a porous heat-resistant layer interposed between the positive and negative electrodes, said positive electrode comprising a positive electrode core member and a positive electrode active material layer carried on the positive electrode core member, said negative electrode comprising a negative electrode core member and a negative electrode active material layer carried on the negative electrode core member, and a separator that comprises a micro-porous film including polyolefin, said separator being interposed between said porous heat-resistant layer and said positive electrode, said battery has a restricting part for restricting vertical movement of said electrode assembly, a distance A from said restricting part to an inner face of the bottom of said battery can and a width B of said negative electrode satisfying the relation: 0.965≦B/A≦0.995, said porous heat-resistant layer comprises an insulating filler and a binder, an amount of said binder being 2 to 8 parts by weight per 100 parts by weight of said insulating filler, said porous heat-resistant layer is formed on a surface of said negative electrode active material layer, said porous heat-resistant layer has a porosity of 40 to 60%, and the width of said negative electrode is larger than that of said positive electrode.