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.

Date of Patent:
Nov. 05, 2002

Filed:

Mar. 07, 2000
Applicant:
Inventors:

Yoshiaki Kikuchi, Toyota, JP;

Shigehiro Kawauchi, Aichi, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02H 3/18 ;
U.S. Cl.
CPC ...
H02H 3/18 ;
Abstract

By finding a voltage difference &Dgr;V between the maximum value and the minimum value of voltage of each cell constituting a battery set and then combining the voltage difference &Dgr;V with current I passing through the battery set into a value pair and store a plurality of the value pairs, the relationship between the voltage difference &Dgr;V and the current I is a relation represented by a straight line with the slope &Dgr;R thereof corresponding to an internal-resistance difference. Therefore, fault in the battery set can be determined from the magnitude of the slope &Dgr;R computed by a least-squares method. Fault determination for a battery set is made more accurate because variations in electromotive force caused by charge-and-discharge patterns and by changes in temperature are canceled when the voltage difference &Dgr;V is determined.


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