Patent ID: 8344700

Claim:
A charging method for charging a secondary battery, the method comprising the steps of: (a) performing constant-current charging with a first current; (b) when, under a condition that a temperature of the secondary battery is less than a reference temperature, a voltage of the secondary battery reaches a first voltage, performing constant-voltage charging at the first voltage, wherein: when the temperature of the secondary battery is equal to or higher than the reference temperature in step (a), performing steps of: (b1) when the voltage of the secondary battery reaches a second voltage lower than the first voltage, performing constant-voltage charging at the second voltage, (b2) after step (b1) and when the temperature of the secondary battery falls below the reference temperature, performing charging with a second current, and (b3) when the voltage of the secondary battery reaches the first voltage, performing constant-voltage charging at the first voltage, and the first current is different from the second current.