Patent ID: 7935445
Filing Date: 2011-05-03
Classification: H01M,Y02E,Y02P

Abstract:
1. A lithium ion secondary battery including: (a) a positive electrode plate comprising a positive electrode active material part and a positive electrode current collector carrying said positive electrode active material part, said positive electrode active material part comprising a positive electrode active material capable of absorbing or desorbing a lithium ion during charge and discharge; (b) a negative electrode plate comprising a negative electrode active material part and a negative electrode current collector carrying said negative electrode active material part, said negative electrode active material part comprising a negative electrode active material capable of absorbing or desorbing a lithium ion during charge and discharge; (c) a separator interposed between said positive electrode plate and said negative electrode plate; (d) an electrolyte; and (e) a battery case accommodating said positive electrode plate, said negative electrode plate, said separator, and said electrolyte, wherein said positive electrode plate and said negative electrode plate are wound around an axis with said separator interposed therebetween, thereby to form an electrode plate assembly, said electrode plate assembly is configured that each edge parallel to a lengthwise direction of said positive electrode active material part is positioned on an outer side of each edge parallel to a lengthwise direction of said positive electrode current collector, said lengthwise direction of each of said positive electrode active material part and positive electrode current collector are perpendicular to the axis of winding of the electrode plate assembly, and an insulating material part extending in the plane of said positive electrode current collector is disposed at each edge parallel to said lengthwise direction of said positive electrode current collector.