| 摘要 |
PURPOSE:To prevent deteriorating a battery characteristic and worsening thermal stability due to repeated charge/discharge by performing the prescribed initial discharge at the time of ending the charge or starting the discharge, in a lithium secondary battery using a lithium metal for its negative pole. CONSTITUTION:At the time of ending a charge or starting a discharge of a battery, the initial discharge within 30 seconds is performed by current density of 5mA/cm<2> or more per unit area of a positive or negative pole. A uniform fine hole is opened to a protective film formed in a lithium surface by the discharge of large current thus performed, and in the case of low current discharge thereafter, lithium is uniformly fused to remove the protective film. Thus by preventing producing needle-shaped lithium due to local deposition in the case of charge thereafter, a charge/discharge life and thermal stability are improved. Further by increasing current density of the initial discharge, a discharge time can be shortened. |
