| 摘要 |
PROBLEM TO BE SOLVED: To provide an extremely safe lithium ion secondary battery causing no burst and firing of the battery in overcharge. SOLUTION: In a film having a through hole of a passage curvature of 1 and having the film thickness of 40 μm or less, in an electrochemical cell having the McMillan number of 10 or less when impregnating the film with an electrolyte and sandwiching the film between a metallic foil electrode (an electrode A) electrochemically stable in oxidation-reduction potential of lithium and an electrode (an electrode B) capable of electrochemically releasing lithium, this separator for the lithium ion secondary battery is characterized in that when an electric current is made to flow so as to deposit metallic lithium on the electrode A, a sudden reduction in an absolute value of voltage of a cell is observed within an electrification quantity of 2 mAh/cm2. |
