BATTERY CAPACITY CALCULATING METHOD, BATTERY CAPACITY CALCULATING APPARATUS, AND BATTERY CAPACITY CALCULATING PROGRAM

摘要

A battery capacity calculating method 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. A battery capacity calculating apparatus (10) is equipped with a voltage measuring circuit (11) which measures the terminal voltage (Vmea) of a battery (1) at the time of discharging, a current measuring circuit (12) which measures the current value (I) of the battery (1) at the time of discharging, and a control circuit (13) which calculates a residual capacity and/or residual power. The operation unit (15) in the control circuit(13) 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 (11) and the current measuring circuit (12), respectively, estimates a discharge curve (Cpre) in the future including the last stage of discharging based on a capacity shift ( DELTA Q) 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 (1) based on the estimated discharge curve (Cpre).