A battery calculating method, apparatus, and program are provided. The
battery capacity calculating method and apparatus can very accurately calculate a residual capacity of a secondary battery especially in the last stage of discharging independently of environmental conditions such as a temperature or a deteriorated state. the
battery capacity calculating apparatus is equipped with a
voltage measuring circuit which measures the
terminal voltage (Vmea) of a battery at the time of discharging, a current measuring circuit which measures the current value (I) of the battery at the time of discharging, and a
control circuit which calculates a residual capacity and / or residual power. The operation unit in the
control circuit calculates a discharged capacity (Qmea) and an apparent discharged capacity (Qocv) based on a
terminal voltage (Vmea) and a current value (I) measured by the
voltage measuring circuit and the current measuring circuit, respectively, estimates a
discharge curve (Cpre) in the future including the last stage of discharging based on a capacity shift (ΔQ) being the difference between the discharged capacity (Qmea) and the apparent discharged capacity (Qocv) during discharging, and calculates the residual capacity and / or the residual power of the battery based on the estimated
discharge curve (Cpre).