Patent ID: 7138775

Claim:
A battery control apparatus comprising: a battery pack including a series combination of cell units; a motor drive control circuit to receive a discharge current from the battery pack to drive a traction motor of a vehicle, and to supply a charge current to the battery pack; a current sensor to sense a discharge/charge current flowing from the battery pack as the discharge current and flowing to the battery pack as the charge current; a voltage detecting circuit to sense a voltage between two separate points in the series combination of the cell unit of the battery pack; a reference voltage drop memory section to store a reference voltage drop quantity representing a decrease in voltage during a predetermined time interval between the two separate points in a reference state; an offset detecting section to compare an actual voltage drop quantity which is a decrease in voltage during the predetermined time interval between the two separate points, sensed by the voltage detecting circuit, with the reference voltage drop quantity stored in the reference voltage drop memory section, to detect a non-discharge/charge-current state of the current sensor in accordance with a result of comparison between the actual voltage drop quantity and the reference voltage drop quantity, and to reserve an output of the current sensor, as an offset quantity when the non-discharge/charge current state is detected; and a correcting section to correct a sensed value of the discharge/charge current sensed by the current sensor, in accordance with the offset quantity reserved by the offset detecting section.