Apparatus for detecting remaining capacity of battery

摘要

When a battery as an energy source for propelling an electric vehicle is repeatedly charged and discharged, the calculated remaining capacity of the battery tends to suffer a large error due to an error of a current sensor which detects a battery current. In order to detect the remaining capacity with high accuracy, a remaining capacity 1 detected on the basis of an integrated value of a discharging current and a remaining capacity 2 detected on the basis of the output power of the battery at a present time are compared with each other, and the remaining capacity is determined depending on the result of comparison. The output power of the battery at the present time depends on the remaining capacity at the present time. Thereafter, after the battery is charged and discharged in repeated cycles, the remaining capacity 1 is presumed as suffering a large error, and the remaining capacity 2 is determined as the remaining capacity, so that the remaining capacity can be detected with accuracy.