1. Technical Field
The present invention relates generally to a battery condition determining apparatus which may be employed in an electric automobile. More particularly, the invention relates to a battery power monitoring apparatus for monitoring available reserve electric power of a storage battery correctly even under the influence of charge polarization.
2. Background Art
Japanese Patent First Publication No. 1-193675 teaches a battery residual life monitoring system which detects an internal resistance of a battery during use to determine a discharge time, and calculates a useful reserve life of the battery by using mapped data representing the relation between a battery internal resistance and a discharge time.
Usually, a storage battery mounted in an electric automobile is discharged and recharged many times during traveling. Particularly, the storage battery is recharged frequently by regenerative braking and in recharge stations, causing so-called charge polarization to occur. It is, therefore, difficult to determine an available reserve capacity of the storage battery based only on its internal resistance, requiring the monitoring of the charge polarization for correctly determining an available reserve capacity remaining in the battery.