Patent ID: 7633265

Claim:
A secondary-battery management apparatus in a power supply system which includes a secondary battery as a backup power supply and supplies power to a load, the secondary-battery management apparatus comprising: a load device provided separately from the load and connected in parallel to the load; a battery-data storage section for storing a load current pattern of current flowing through the load and a maximum current, which is the maximum value of current flowing through the load; a measurement-conditions input section for obtaining discharge timing to discharge the secondary battery by reducing an output of a rectifier, and checking timing to check the capacity of the secondary battery by using the load current pattern; an arithmetic section for calculating a remaining capacity and a remaining lifetime of the secondary battery in accordance with information on a temperature of the secondary battery in a standby state, in which the secondary battery is not being charged nor discharged, for calculating the remaining capacity of the secondary battery in accordance with information on a measured discharging current from the secondary battery while the secondary battery is in a discharging state, and for calculating the remaining capacity of the secondary battery in accordance with information on a measured charging current to the secondary battery while the secondary battery is in a charging state; a first control section for judging the reduced capacity of the secondary battery by supplying the load current stored in the battery-data storage section to the load device at the discharge timing to discharge the secondary battery by reducing the output of the rectifier; and a second control section for calculating the discharge duration of the secondary battery by using the load current pattern stored in the battery-data storage section at the checking timing to check the battery capacity by using the load current pattern.