The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 09, 2003
Filed:
Oct. 09, 2001
Yazaki Corporation, Tokyo, JP;
Abstract
A method and apparatus are provided, by which a state of charge of a battery is accurately computed without being influenced by the polarization effect. An estimated voltage of the battery in a constant load discharge with a predetermined large current value is estimated from a voltage-current characteristic when the discharge current of the constant load discharging process by the battery that is in an equilibrium state is decreasing from the predetermined large current value corresponding to a maximum supplying electric power to the load. A difference between the estimated voltage and an open circuit voltage, which estimates the estimated voltage and is a terminal voltage of the battery that is in an equilibrium state before the start of the constant load discharge by using the predetermined large current value, is calculated. Then, the difference is memorized by first memory means for memorizing a residual voltage drop defining as the residual voltage drop due to a residual polarization at the end of the discharging process of the battery . The residual voltage drop memorized by the first memory means is added to the estimated voltage of the battery , thereby a present charging capacity of the battery is computed.