Patent ID: 6696818
Filing Date: 2004-02-24
Classification: G01R

Abstract:
A method for computing a charging efficiency, which is a ratio of an electrical quantity charged in a battery as an electromotive force to a total electrical quantity supplied to the battery, at any one point in time between a start and an end of charging of the battery, the method comprising:measuring an initial resistance of the battery at the start of the charging, measuring a voltage and a current between a pair of terminals of the battery at the one point to obtain an inner resistance of the battery at the one point, obtaining a resistance difference which is a difference of the inner resistance at the one point and the initial resistance, and obtaining a ratio of the resistance difference to a full charged state resistance that is a resistance of the battery at a full charged state of the battery, whereby, a charging efficiency of the battery at the one point is computed based on the ratio.