| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a rolled copper foil suitable as the negative electrode collector material of a secondary battery, and having excellent charge/discharge cycle life. <P>SOLUTION: The copper foil for the negative electrode collector of a secondary battery has a tensile strength in a direction parallel with the rolling direction that drops below 250 MPa when the copper foil is annealed at 200°C for 30 min. Young's moduli of the annealed foil are measured in five directions where the angle between the rolling direction is 0 degree, 22.5 degree, 45 degree, 67.5 degree and 90 degree. When the maximum value and minimum value out of the five Young's moduli are Emax and Emin, the Emax/Emin is 1.3 or smaller. <P>COPYRIGHT: (C)2012,JPO&INPIT |
