Patent ID: 7931983
Filing Date: 2011-04-26
Classification: H01M,Y02E,Y02P,Y10T

Abstract:
1. A lithium ion secondary battery comprising: a positive electrode capable of absorbing and desorbing lithium ion; a negative electrode capable of absorbing and desorbing lithium ion; a porous film interposed between said positive electrode and said negative electrode; and a non-aqueous electrolyte; wherein said porous film is adhered to a surface of at least one of said positive electrode and said negative electrode, said porous film comprises a filler and a resin binder, a content of said resin binder in said porous film is 1.5 to 8 parts by weight per 100 parts by weight of said filler, an amount of said resin binder is smaller in a first surface side where said porous film is in contact with said surface of said electrode, and larger in a second surface side opposite to said first surface side, and said positive electrode and said negative electrode are wound interposing only said porous film.