TERMINAL VOLTAGE ESTIMATION METHOD OF BATTERY AND ITS DEVICE, OPEN CIRCUIT VOLTAGE OPERATION METHOD OF BATTERY AND ITS DEVICE, BATTERY CAPACITY OPERATION METHOD AND ITS DEVICE

摘要

PROBLEM TO BE SOLVED: To operate accurately the charging state of a battery without being influenced by polarization. SOLUTION: A voltage-current characteristic including the influence of polarization during decrease of a discharge current of a battery 13 acquired by a polarization influence characteristic deducing means 23A from the discharge current and a terminal voltage during decrease of the discharge current of constant-load discharge by a current value sufficient for removing charging side polarization generated in the battery 13 at least just before discharge is shifted in the voltage axis direction by a post-shift polarization influence characteristic deducing means 23B so that the voltage value at a reference current value on the characteristic agrees with a reference voltage value at the reference current value on the voltage-current characteristic not including the influence of polarization depending only on a pure resistance component of the battery 13, and a remaining voltage drop value stored beforehand in a remaining voltage drop value storage means 27 is added to the value of a present estimated voltage of the battery 13 estimated by an estimated voltage estimation means 23C by using the post- shift voltage-current characteristic, to thereby calculate a present open circuit voltage of the battery 13.