Battery capacity calculating method, battery capacity calculating apparatus and battery capacity calculating program

A battery capacity calculating apparatus for calculating a residual capacity and/or residual power of a secondary battery, comprising:

• voltage measuring means for measuring a terminal voltage Vmea of said secondary battery at a time of discharging;
• current measuring means for measuring a current value I of said secondary battery at the time of discharging;
• and
• operation processing means for calculating the residual capacity and/or the residual power of said secondary battery,
• wherein said operation processing means calculates an equilibrium voltage curve Cequ showing a relation between a discharged capacity and an equilibrium voltage in said secondary battery, calculates a discharged capacity Qmea of said secondary battery based on the terminal voltage Vmea measured with said voltage measuring means and the current value I measured with said current measuring means, calculates an apparent equilibrium voltage Vocv by adding a voltage drop ΔVdc by a direct current resistance Rdc to the terminal voltage Vmea, calculates an apparent discharged capacity Qocv corresponding to the apparent equilibrium voltage Vocv based on the equilibrium voltage curve Cequ, calculates a capacity shift ΔQ being a difference between the discharged capacity Qmea and the apparent discharged capacity Qocv, and estimates a discharge curve Cpre in a future based on the capacity shift ΔQ.

A battery capacity calculating program capable of being executed by a computer for calculating a residual capacity and/or residual power of a secondary battery, comprising:

• equilibrium voltage curve calculating processing for calculating an equilibrium voltage curve Cequ showing a relation between a discharged capacity and an equilibrium voltage of said secondary battery;
• voltage current measuring processing for measuring a terminal voltage Vmea and a current value I of said secondary battery at a time of discharging;
• discharged capacity calculating processing for calculating a discharged capacity Qmea of said secondary battery based on the terminal voltage Vmea and the current value I, both measured by said voltage current measuring processing;
• apparent equilibrium voltage calculating processing for calculating an apparent equilibrium voltage Vocd by adding a voltage drop ΔVdc by a direct current resistance Rdc to the terminal voltage Vmea;
• apparent discharged capacity calculating processing for calculating an apparent discharged capacity Qocv corresponding to the apparent equilibrium voltage Vocv calculated by said equilibrium voltage calculating processing based on said equilibrium voltage curve Cequ calculated by said equilibrium voltage curve calculating processing;
• capacity shift calculating processing for calculating a capacity shift ΔQ being a difference between the discharged capacity Qmea and the apparent discharged capacity Qocv;
• and
• estimating processing for estimating a discharge curve Cpre in a future based on the capacity shift ΔQ calculated by said capacity shift calculating processing.