Patent ID: 9202631
Filing Date: 2015-12-01
Classification: C08J,H01G,H01M,Y02E,Y02P

Abstract:
1. A lithium ion secondary battery comprising; a positive electrode, a negative electrode, and an electrolyte solution, wherein at least one of the positive electrode and the negative electrode comprises: an electrode composite material layer including a binder and an electrode active material, a collector to which the electrode composite material layer is adhered, and a porous film provided on a surface of the electrode composite material layer, wherein the porous film is composed of a mixture comprising; a water soluble polymer, an inorganic filler, and a water insoluble particulate polymer comprising 0.5 to 40 mass % of a monomer unit including a hydrophilic group selected from the group consisting of carboxylic acid group, hydroxyl group and sulfonic acid group, a content ratio of said water soluble polymer in said porous film is 0.1 to 5 parts by mass per 100 parts by mass of said inorganic filler, the water soluble polymer is a thickening polysaccharide selected from the group consisting of cellulose base semisynthetic polymers having an etherification degree within a range of 0.5 to 1.0, sodium salts, and ammonium salts thereof, and has an average polymerization degree within a range of 500 to 2500, a content ratio of the water insoluble particulate polymer is 0.1 to 15 parts by mass per 100 parts by mass of the inorganic filler, and said electrolyte solution is an organic electrolyte solution wherein a supporting electrolyte is dissolved in an organic solvent.