| 摘要 |
<p>Charging and discharging of a secondary battery is stopped from a time point (t1) when an ignition switch is turned off. A depolarization time (Tr) required for polarization to disappear after the charging and discharging is stopped varies depending on the temperature of the secondary battery. The battery voltage is periodically detected during the time from when the ignition switch is turned off until a predetermined time corresponding to the depolarization time (Tr) elapses, and the open voltage in an equilibrium state in which polarization disappears is sequentially estimated based on the transition of the battery voltage. When the ignition switch is turned on after the predetermined time has elapsed from when the ignition switch was turned off, the value of the battery voltage detected when the ignition switch is turned on is regarded as an open voltage and the SOC when the use of the secondary battery is started is estimated. When the ignition switch is turned on before the predetermined time elapses from when the ignition switch is turned off, the value of the open voltage estimated at that time point is regarded as an open voltage and the SOC when the use of the secondary battery is started is estimated.</p> |
