Patent ID: 6677729
Filing Date: 2004-01-13
Classification: G01R

Abstract:
A method for computing a voltage drop divided along a plurality of factors for a battery to supply an electrical power to a load, the voltage drop being due to the factors which are separately analyzed in use of a correlation between a discharge current and a terminal voltage of the battery, the method comprising the steps of:measuring cyclically a discharge current and a voltage between a pair of terminals of the battery while a rush current is flowing in the load electrically connected to the pair of terminals, the rush current simply decreasing from a peak to a constant value after the rush current simply increases up to the peak, obtaining a first approximate equation showing the correlation between the current and the voltage in a region where the discharge current is increasing and a second approximate equation showing a correlation between the current and the voltage is obtained in a region where the discharge current is decreasing, and calculating a voltage from each of the first and second approximate equations at a point where the discharge current is zero so that a difference between the two voltages at the point where the discharge current is zero is obtained, wherein the difference is determined to be a total voltage drop due to a concentration polarization of the battery.