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

Abstract

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 (V) 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 (Q) and an apparent discharged capacity (Q) based on a terminal voltage (V) and a current value (I) measured by the voltage measuring circuit and the current measuring circuit, respectively, estimates a discharge curve (C) in the future including the last stage of discharging based on a capacity shift (ΔQ) being the difference between the discharged capacity (Q) and the apparent discharged capacity (Q) during discharging, and calculates the residual capacity and/or the residual power of the battery based on the estimated discharge curve (C).