Method and apparatus for controlling residual battery capacity of secondary battery

A residual battery capacity control apparatus for a secondary battery, comprising:

• a current detection unit that detects a current flowing through the secondary battery;
• a residual battery capacity operation unit that performs an operation on a residual battery capacity by multiplying a current signal from the current detection unit by a predetermined charge efficiency;
• a voltage detection unit that detects an output voltage from the secondary battery;
• an average voltage calculation unit that calculates an average voltage value of voltage signals output from the voltage detection unit for a predetermined period of time;
• an average residual battery capacity calculation unit that calculates an average value of residual battery capacities obtained by the operation by the residual battery capacity operation unit for a predetermined period of time;
• a reference voltage storage unit that stores a reference voltage value of the secondary battery, corresponding to the average value of residual battery capacities obtained from the average residual battery capacity calculation unit;
• a comparison unit that compares the average voltage value obtained from the average voltage calculation unit and the reference voltage value obtained from the reference voltage storage unit;
• and
• a charge efficiency setting unit that sets the predetermined charge efficiency variably with respect to the residual battery capacity operation unit, based on a result of the comparison by the comparison unit.

A residual battery capacity control apparatus for a secondary battery, comprising:

• a battery pack composed of a combination of a plurality of electric cells, each of which is a secondary battery, and used in a middle charged state,
• a current detection unit that detects a current flowing through the battery pack;
• a residual battery capacity operation unit that performs an operation on a residual battery capacity by multiplying a current signal from the current detection unit by a predetermined charge efficiency;
• a voltage detection unit that detects an output voltage from the battery pack;
• an average voltage calculation unit that calculates an average voltage value of voltage signals output from the voltage detection unit for a predetermined period of time;
• an average residual battery capacity calculation unit that calculates an average value of residual battery capacities obtained by the operation by the residual battery capacity operation unit for a predetermined period of time;
• a reference voltage storage unit that stores a reference voltage value of each secondary battery, corresponding to the average value of residual battery capacities obtained from the average residual battery capacity calculation unit;
• a comparison unit that compares the average voltage value obtained from the average voltage calculation unit and the reference voltage value obtained from the reference voltage storage unit;
• and
• a charge efficiency setting unit that sets the predetermined charge efficiency variably with respect to the residual battery capacity operation unit, based on a result of the comparison by the comparison unit.