Patent ID: 8114543
Filing Date: 2012-02-14
Classification: H01M,Y02E,Y02P

Abstract:
1. A lithium ion secondary battery, comprising: a positive electrode; a negative electrode; and a separator provided between the positive electrode and the negative electrode, the positive electrode and the negative electrode each having a collector and an active material layer provided over the collector, and a relationship Ts≧4Tc being satisfied, where Ts is a puncture strength of the separator, and Tc is a puncture strength of the collector of the positive electrode and/or the negative electrode, the puncture strength being a maximum load when a needle punctures a test piece at a rate of 200 mm/min, using a needle in which a conical portion with a height of 2.6mm is formed at a tip of a shaft with a diameter of 3 mm, where a radius of curvature of the tip of the conical portion is 40 μm.