摘要 |
Disclosed is a charging method for one or more non-aqueous electrolyte secondary batteries by n steps of constant-current charging processes, where n is an integer equal to or greater than 2. The n steps include: (1) charging the secondary batteries at a current Ic(k) until a charge voltage per one battery reaches a voltage Ec(k), where k is an integer equal to or greater than 1 and equal to or smaller than n-1; and (2) when the charge voltage per one battery reaches the voltage Ec(k), charging the secondary batteries at a current Ic(k+1) smaller than the current Ic(k) until the charge voltage per one battery reaches a voltage Ec(k+1) higher than the voltage Ec(k), in which (3) the currents Ic(k) and Ic(k+1) are set according to frequency of use or number of charge and discharge cycles of the secondary batteries. |