LITHIUM ION BATTERY AND METHOD FOR MANUFACTURING THE SAME

摘要

A lithium ion battery comprises an electrode body (30) formed by laminating a long positive electrode sheet (32) and a long negative electrode sheet (34) through a separator (35) and then winding the laminate. The negative electrode sheet (34) has an active material layer (344) formed on a current collector (342) while leaving one edge of the collector along the longitudinal direction uncovered in the form of a strip, and the negative electrode sheet (34) is laminated such that the portion (342a), where the strip-shaped active material layer is not formed, protrudes beyond the positive electrode sheet (32). On the outer surface of the negative electrode active material layer (344), a porous inorganic layer (346) is so formed as to extend from a plane portion (344a) of the active material layer to the surface of the current collector (342) via an end portion (344b). The mass per unit area ratio Wa/Wb between the end portion (344b) and the plane portion (344a) of the inorganic layer (346) is in the range of 0.5-1.2.