US4595880A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Battery state of charge gauge
Assignee: Ford Global Technologies LLC
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Filing: 1983-08-08
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Granted: 1986-06-17
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Expires: 2003-08-08
Abstract
Abstract A method of computing the state of charge for a battery including the steps of sensing the battery voltage and current, and computing the used battery capacity, C u , and the average battery current, I. The total battery capacity, C t is calculated from average current using the Peukert equation. The state of charge is calculated as a function of C u /C t to account for temperature and aging effects, recuperation effects, regeneration effects, and current variation effects.
Inventors
- 👤 Prabhakar B. Patil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:39
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/36; G01R31/382; G01R31/3842
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
130 words
A method for computing the state of charge for a battery including the steps of: measuring I p , wherein Ip is the battery discharge current; determining I, wherein I is the average battery current, by calculating ##EQU5## empirically determining k and n for the battery, wherein k and n are Puekert constants; calculating the total capacity, C t , of the battery using the Puekert equation, C t =k·I n ; reevaluating k, n as a function of temperature and age of the battery; calculating the used battery capacity, C u , by integrating battery current with respect to time; calculating the percent state of charge using (1-C u /C t ) (100), and repeating the above steps to determine the state of charge the battery at subsequent times.
Claim 2
Independent Claim
130 words
A method for computing the state of charge for a battery including the steps of: measuring I p , wherein Ip is the battery discharge current; determining I, wherein I is the average battery current, by calculating ##EQU5## empirically determining k and n for the battery, wherein k and n are Puekert constants; calculating the total capacity, C t , of the battery using the Puekert equation, C t =k·I n ; reevaluating k, n as a function of temperature and age of the battery; calculating the used battery capacity, C u , by integrating battery current with respect to time; calculating the percent state of charge using (1-C u /C t ) (100), and repeating the above steps to determine the state of charge the battery at subsequent times.
Claim 3
Dependent Claim
36 words
A method as recited in claim 1 further comprising the steps of determining if the battery has gone through a charging-discharging cycle of between about eighty percent and forty percent of the maximum state of charge.
Claim 4
Dependent Claim
33 words
A method as recited in claim 2 wherein successive readings of battery current and temperature are made about 100 times per second and an average of the readings is taken about every second.
Claim 5
Dependent Claim
36 words
A method as recited in claim 3 wherein the effects of recuperation are taken into effect by detecting the occurrence of a zero battery current of about 300 seconds at which time recuperation is substantially completed.
Claim 6
Independent Claim
84 words
A method for detecting in a battery an abnormal battery cell condition including the steps of: measuring the battery voltage V, and current, I,; calculating the used battery capacity, C u , by integrating battery current with respect to time; determining the partial derivative of battery voltage, V, with respect to used battery capacity, C u ; comparing dV/dC u to a predetermined value; and determining a battery cell has an undesirably high dynamic resistance if dV/dC u is greater than the predetermined value.
Claim 7
Independent Claim
84 words
A method for detecting in a battery an abnormal battery cell condition including the steps of: measuring the battery voltage V, and current, I,; calculating the used battery capacity, C u , by integrating battery current with respect to time; determining the partial derivative of battery voltage, V, with respect to used battery capacity, C u ; comparing dV/dC u to a predetermined value; and determining a battery cell has an undesirably high dynamic resistance if dV/dC u is greater than the predetermined value.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-06-16 | 1989-12-16 | 1990-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-16 | 1993-12-16 | 1994-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-16 | 1997-12-16 | 1998-06-17 | $7700.00 | Window Closed / Lapsed |