| 摘要 |
An object of the present invention is to eliminate deviation in the quality of a chromate film provided on a copper foil for a negative electrode current collector to eliminate fluctuation of electric capacity in a lithium ion secondary battery. To achieve the object, as the copper foil for a negative electrode current collector of a lithium ion secondary battery, a copper foil provided with a chromate film for a negative electrode current collector in which Cr(OH)3 constitutes 85 area % or more of the chromate film is employed. Further, the copper foil provided with a chromate film for a negative electrode current collector according to the present application is preferable to be that the apparent orientation number N of oxygen closest to chrome in the chromate film is 4.5 or more. |
