Patent ID: 6788068
Filing Date: 2004-09-07
Classification: G01R

Abstract:
A method of measuring a pure resistance of an on-vehicle battery for supplying electric power to loads in the vehicle comprising the steps of:periodically measuring a discharge current and terminal voltage of the battery while a rush current flows into a predetermined constant, the rush current first monotonically increasing from zero to a peak value and subsequently monotonically decreasing from the peak value to a steady value; computing a first approximate expression of a current-voltage characteristic for the increasing discharge current and a second approximate expression of a current-voltage characteristic for the decreasing discharge current, said current-voltage characteristic indicating a correlation between the discharge current and terminal voltage of the battery; and computing an intermediate value of two values of the terminal voltage change per unit current change at points corresponding to the peak values of the first and second approximate expressions excluding a voltage drop caused by a concentration polarization component when the first and second approximate expressions include the voltage drop, wherein the intermediate value computed is measured as the pure resistance of the battery.