US4743855A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and apparatus for measuring the state of discharge of a battery
Assignee: Individual
•
Filing: 1986-11-03
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Granted: 1988-05-10
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Expires: 2006-11-03
Abstract
Abstract A method is described of measuring the state of discharge of a battery, i.e. the ratio between the supplied capacity and the nominal capacity. The method consists in measuring a first internal impedance of the battery at a first frequency and a second internal impedance of the battery at a second frequency, then in determining the argument of the difference between the internal impedances, the resulting argument being representative of the state of discharge of the battery. The method can be used to advantage to check in a rapid, accurate and non-destructive way whether batteries to be used in portable appliances, e.g. electronic watches, are in good working order before being fitted into the appliances.
Inventors
- 👤 Jean-Paul Randin
- 👤 Fredy Zuellig
- 👤 Claude-Eric Leuenberger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:54
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/36; G01R31/389
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
76 words
A method of measuring the state of discharge of a battery having an internal impedance, which comprises: (a) measuring a first internal complex impedance of the battery at a first frequency; (b) measuring a second internal complex impedance of the battery at a second frequency; (c) determining the complex difference between said internal complex impedances; and (d) determining the argument of said complex difference, said argument being representative of the state of discharge of the battery.
Claim 2
Independent Claim
76 words
A method of measuring the state of discharge of a battery having an internal impedance, which comprises: (a) measuring a first internal complex impedance of the battery at a first frequency; (b) measuring a second internal complex impedance of the battery at a second frequency; (c) determining the complex difference between said internal complex impedances; and (d) determining the argument of said complex difference, said argument being representative of the state of discharge of the battery.
Claim 3
Dependent Claim
20 words
A method of measurement as in claim 1, wherein the lower of said frequencies lies between 0.1 and 10 Hz.
Claim 4
Dependent Claim
30 words
A method of measurement as in claim 1, wherein the higher of said frequencies is such that the reactive part of said internal impedance is approximately zero at this frequency.
Claim 5
Dependent Claim
21 words
A method of measurement as in claim 1, wherein the higher of said frequencies is in the region of 10 kHz.
Claim 6
Dependent Claim
90 words
Measuring apparatus for ascertaining the state of discharge of a battery, which comprises means for preventing the battery from issuing a direct current, means for measuring a first internal complex impedance of the battery at a first frequency and a second internal complex impedance of the battery at a second frequency, means for determining the complex difference between said internal complex impedances and the argument of said complex difference, and means for displaying the value of said argument, said argument being representative of the state of discharge of the battery.
Claim 7
Dependent Claim
90 words
Measuring apparatus for ascertaining the state of discharge of a battery, which comprises means for preventing the battery from issuing a direct current, means for measuring a first internal complex impedance of the battery at a first frequency and a second internal complex impedance of the battery at a second frequency, means for determining the complex difference between said internal complex impedances and the argument of said complex difference, and means for displaying the value of said argument, said argument being representative of the state of discharge of the battery.
References Cited (Backward Citations)
US3984762A
Cited
US4259639A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-05-10 | 1991-11-09 | 1992-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-10 | 1995-11-09 | 1996-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-10 | 1999-11-09 | 2000-05-10 | $7700.00 | Window Closed / Lapsed |