Patent ID: 6531875
Filing Date: 2003-03-11
Classification: G01R

Abstract:
A vehicle battery's open circuit voltage estimating method for estimating an open circuit voltage of a vehicle-borne battery supplying electric power to vehicle-borne loads, comprising the steps of:measuring a disconnected voltage of the battery multiple times in a definite period of time after a predetermined period of time after completion of charge or discharge of the battery; determining a power approximate expression having a negative power number by using a difference value of the measured disconnected voltage and an assumed open circuit voltage; repeating the determination of the power approximate expression by updating the assumed open circuit voltage until the power number of the determined power approximate expression becomes âˆ’0.5 or about âˆ’0.5; and estimating the assumed open circuit voltage to be the open circuit voltage when the power number becomes âˆ’0.5 or about âˆ’0.5.