Battery remaining capacity measuring apparatus

• US 5,744,931 A
• Filed: 08/30/1996
• Issued: 04/28/1998
• Est. Priority Date: 09/01/1995
• Status: Expired due to Term

• Current Assignee: Yazaki Corporation
• Original Assignee: Yazaki Corporation
• Inventors: Ichikawa, Hiroshi, Arai, Youichi
• Primary Examiner(s): TSO, EDWARD H
• Application Number:
  US08/705,677
• Time in Patent Office: 606 Days
• Field of Search: 320/13, 320/21, 320/29, 320/30, 320/31, 320/32, 320/39, 320/40, 320/43, 320/44, 320/48, 324/427, 324/428, 324/429, 324/433, 340/636, 429/90, 364/481, 364/483
• US Class Current: 320/149
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/386 using test-loads
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: H01M 10/46 Accumulators structurally combined with charging apparatus circuits for charging H02J7/00
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A remaining capacity operation portion 19 provides an approximate linear function (I=aV+b) having a voltage-current characteristic by a method of least squares according to an open circuit voltage when a load 1 is disconnected to a battery 3, a closed circuit voltage when a battery 3 is connected to a load 1 which is detected for every predetermined time and a current passing through a load, where a reference value (I<0) is substituted in this approximate linear function, which a display portion 27 displays as an remaining capacity voltage.

Claims

1. A battery remaining capacity measuring apparatus for measuring an open circuit until a battery is connected to a load together with a start of an operation, measuring a plurality of a closed circuit voltage and a current for every predetermined time after a state of said closed circuit, and obtaining an approximate linear function which shows a voltage-current characteristic according to said voltage and current, said apparatus comprising:

a remaining capacity operation portion for obtaining a voltage value whereby a reference value (I<

0 ) is substituted in said approximate linear function whenever said approximate linear function, and displaying said voltage value as a remaining capacity operation portion.

2. A battery remaining capacity measuring apparatus according to claim 1, wherein said remaining capacity operation portion comprising:

line extension means for creating an approximate line where an approximate linear function is extended on a coordinate axis having -I axis and +V axis; and

remaining capacity calculation means for obtaining a voltage value on an intersecting point where an approximate line crosses at a reference value (I<

0 ), and displaying the voltage value as a remaining capacity voltage.