STATE OF CHARGE DETECTION APPARATUS AND STATE OF CHARGE DETECTION METHOD

摘要

PROBLEM TO BE SOLVED: To estimate an SOC while suppressing an increase of the estimation error of the SOC and suppressing unnecessarily long standby time in comparison with a configuration, in which the same condition is used regardless of to which OCV region a terminal voltage value of a power storage element belongs.SOLUTION: A CPU 35 divides a standby time for the CPU 35 to estimate an SOC value of a secondary battery 2 for a low-change-rate voltage region and a high-change-rate voltage region. When determining an elapse of the standby time, the CPU 35 estimates the SOC of the secondary battery 2 from the terminal voltage value of the secondary battery 2 at the time of the determination on the basis of an OCV-SOC curve.