OPEN CIRCUIT VOLTAGE ESTIMATION DEVICE STATE ESTIMATION DEVICE METHOD OF OPEN CIRCUIT VOLTAGE ESTIMATION

摘要

An object of the present invention is to early estimate the open-circuit voltage of a battery element. The battery management apparatus (BMS) of the present invention includes a voltage measurement circuit for measuring a voltage value V of each unit cell, which is an example of a chargeable element, and a CPU. The CPU measures the voltage value V of each unit cell at predetermined time intervals after completion of charge / discharge of the assembled battery, performs processing (S8) in association with the elapsed time T from the charge / discharge end timing of the assembled battery, (S14) calculating a calculation time (W) by multiplying a value Xp representing the elapsed time Tp of the elapsed time Tp by the coefficient determined for each active material of each unit cell by a common logarithm, and calculating a slope (Step S16) of calculating an approximate equation of an approximate straight line of the extreme point P by using the approximate expression P and a process (S18) of estimating the approximate expression as the open-circuit voltage Y by substituting the calculated time W.