BATTERY STATE-OF-CHARGE ESTIMATOR

摘要

A battery ECU estimates the SOC by integrating the battery current measured by a current sensor, and the battery voltage Vn is measured by a voltage sensor and the battery temperature Tn is measured by a thermometer if the fluctuation of the charging/discharging current is great (S204). If the number m of estimations of SOCn is m<10, m is incremented (S208). The battery internal resistance Rn is estimated from the measured battery temperature Tn by using a correlation map showing the correlation between the previously stored battery temperature T and the battery internal resistance R (S210). An estimation charging/discharging current In is determined using the measured battery voltage Vn, the battery open voltage Vocvn-1 determined on the basis of the previously estimated charged state, and the estimated battery internal resistance Rn (S212). The SOCn is estimated by integrating the estimated charging/discharging current In (S214). If the number m of estimations of the SOCn is m=10 (S206), the number m of estimations is changed to 0 (S220). The charging/discharging current in is measured by a current sensor (S222). The battery internal resistance Rn is calculated from the battery voltage Vn and the charging/discharging current in (S224). The battery temperature Tn is also measured, and the T-R correlation map is corrected (S226).