Patent ID: 6104165
Filing Date: 2000-08-15
Classification: H01M,Y02E

Abstract:
A method for charging a secondary battery, wherein at a first stage a prescribed charging current C1, expressed as a C rate, is supplied to a secondary battery, the output voltage of said secondary battery being monitored and, when said output voltage of said secondary battery reaches a pre-established voltage value, a transition is made to a second stage, at which a charging current C2, which is 1/N of C1 (where N is an arbitrary integer value or a real value with a decimal part), which was the current used in said first stage, is supplied to said secondary battery and, when said output voltage of said secondary battery reaches a pre-established voltage that is one and the same with said pre-established voltage, a transition is made to a third stage at which a charging current C3 which is 1/M of C2 (where M is an arbitrary integer value or a real value with a decimal part and can also be equal to N), which was the current used in said first stage, is supplied to said secondary battery and thereafter same is performed, so that each time said output voltage of said secondary battery reaches a pre-established voltage value, said charging current that is supplied to said secondary battery is reduced by a prescribed ratio as charging of said secondary battery proceeds, and wherein when using a charging method which employs switching regulator which causes the amount of said charging current to vary in accordance with the duty cycle of one pulse, said method of charging a secondary battery is a method in which the configuration is such that a protective circuit is provided so that a voltage greater than a pre-established voltage value is not applied to an output terminal of the secondary battery.