Method for detecting remaining battery current, voltage, and temperature capacity by continuously monitoring

• US 5,650,712 A
• Filed: 07/03/1995
• Issued: 07/22/1997
• Est. Priority Date: 07/04/1994
• Status: Expired due to Term

• Current Assignee: DENSO Corporation
• Original Assignee: Nippon Soken, Inc.
• Inventors: Makino, Daisuke, Uchida, Mitsunobu, Kawai, Toshiyuki
• Primary Examiner(s): TSO, EDWARD H
• Application Number:
  US08/497,763
• Time in Patent Office: 750 Days
• Field of Search: 320/5, 320/13, 320/22, 320/30, 320/35, 320/39, 320/44, 320/48, 340/635, 340/636, 429/61, 429/90, 324/427, 324/430, 324/431, 324/433
• US Class Current: 324/427
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10S 320/21 State of charge of battery

Abstract

A map charging index representing discharge characteristics of a battery is obtained based on a battery voltage under a predetermined discharging operation. The map charging index indicates 100 at a first battery voltage obtainable immediately after the battery starts the discharging operation from a fully charged condition and also indicates 0 at a second battery voltage obtainable when the battery substantially ceases the discharging operation. An accumulative charging index is calculated by subtracting a charged capacity from a temporary full-charge capacity of the battery. The temporary full-charge capacity is corrected based on a difference between the map charging index and the accumulative charging index, thereby obtaining a corrected full-charge capacity. And, a dischargeable capacity of the battery is calculated by subtracting the discharged capacity from the corrected full-charge capacity.

Claims

1. A battery charging condition detecting method comprising steps of:

obtaining a map charging index representing discharge characteristics of a battery based on a battery voltage under a predetermined discharging operation, said map charging index indicating 100 at a first battery voltage obtainable immediately after said battery starts said predetermined discharging operation from a fully charged condition and also indicating 0 at a second battery voltage obtainable when said battery substantially ceases said predetermined discharging operation;

calculating an accumulative charging index by subtracting a charged capacity from a temporary full-charge capacity of said battery;

correcting said temporary full-charge capacity based on a difference between said map charging index and said accumulative charging index, thereby obtaining a corrected full-charge capacity; and

calculating a dischargeable capacity of said battery by subtracting a discharged capacity from said corrected full-charge capacity.

2. The battery charging condition detecting method defined by claim 1, further comprises steps of:

obtaining a coefficient based on a ratio of a total discharge capacity of said battery during said predetermined discharging operation to a nominal capacity of said battery, said coefficient being utilized to obtain said temporary full-charge capacity used in calculating said accumulative charging index.

3. The battery charging condition detecting method defined by claim 2, wherein said coefficient is corrected by an ambient temperature of the battery.

4. The battery charging condition detecting method defined by claim 1, further comprises a step of correcting said accumulative charging index based on said dischargeable capacity.

5. The battery charging condition detecting method defined by claim 1, further comprises a step of calculating a deterioration factor of the battery by dividing said corrected full-charge capacity by a nominal capacity of the battery.

6. The battery charging condition detecting method defined by claim 1, further comprises steps of:

obtaining a full-charge capacity correction coefficient based on a ratio of a change of said map charging index to a change of said accumulative charging index; and

multiplying said full-charge capacity correction coefficient with said temporary full-charge capacity to obtain said corrected full-charge capacity.

7. The battery charging condition detecting method defined by claim 1, further comprises a step of correcting map data corresponding to said map charging index by multiplying a residual voltage ratio, said residual voltage ratio representing a degree of actual change of said first battery voltage.

8. The battery charging condition detecting method defined by claim 1, further comprises steps of:

detecting a plurality of discharge currents and corresponding battery voltages when said battery is in said predetermined discharging operation;

prohibiting said step of detecting said plurality of discharge currents and said corresponding battery voltages when said battery is subjected to a transitory charging phenomenon under said predetermined discharging operation until a momentarily charged capacity is canceled by a succeeding discharge capacity;

obtaining an internal resistance of said battery by statistically processing said plurality of discharge currents and said corresponding battery voltages detected; and

estimating a battery voltage corresponding to a given discharge current based on said internal resistance.

9. The battery charging condition detecting method defined by claim 2, further comprises a step of correcting said accumulative charging index based on said dischargeable capacity.

10. The battery charging condition detecting method defined by claim 2, further comprises a step of calculating a deterioration factor of said battery by dividing said corrected full-charge capacity by said nominal capacity of the battery.

11. The battery charging condition detecting method defined by claim 2, further comprises steps of:

obtaining a full-charge capacity correction coefficient based on a ratio of a change of said map charging index to a change of said accumulative charging index; and

multiplying said full-charge capacity correction coefficient with said temporary full-charge capacity to obtain said corrected full-charge capacity.

12. The battery charging condition detecting method defined by claim 2, further comprises a step of correcting map data corresponding to said map charging index by multiplying a residual voltage ratio, said residual voltage ratio representing a degree of actual change of said first battery voltage.

13. The battery charging condition detecting method defined by claim 2, further comprises steps of:

detecting a plurality of discharge currents and corresponding battery voltages when said battery is in said predetermined discharging operation;

prohibiting said step of detecting said plurality of discharge currents and said corresponding battery voltages when said battery is subjected to a transitory charging phenomenon under said predetermined discharging operation until a momentarily charged capacity is canceled by a succeeding discharge capacity;

obtaining an internal resistance of said battery by statistically processing said plurality of discharge currents and said corresponding battery voltages detected; and

estimating a battery voltage corresponding to a given discharge current based on said internal resistance.

14. The battery charging condition detecting method defined by claim 3, further comprises a step of correcting said accumulative charging index based on said dischargeable capacity.

15. The battery charging condition detecting method defined by claim 3, further comprises steps of:

obtaining a full-charge capacity correction coefficient based on a ratio of a change of said map charging index to a change of said accumulative charging index; and

multiplying said full-charge capacity correction coefficient with said temporary full-charge capacity to obtain said corrected full-charge capacity.

16. The battery charging condition detecting method defined by claim 3, further comprises a step of correcting map data corresponding to said map charging index by multiplying a residual voltage ratio, said residual voltage ratio representing a degree of actual change of said first battery voltage.

17. The battery charging condition detecting method defined by claim 3, further comprises steps of:

detecting a plurality of discharge currents and corresponding battery voltages when said battery is in said predetermined discharging operation;

prohibiting said step of detecting said plurality of discharge currents and said corresponding battery voltages when said battery is subjected to a transitory charging phenomenon under said predetermined discharging operation until a momentarily charged capacity is canceled by a succeeding discharge capacity;

obtaining an internal resistance of said battery by statistically processing said plurality of discharge currents and said corresponding battery voltages detected; and

estimating a battery voltage corresponding to a given discharge current based on said internal resistance.

18. The battery charging condition detecting method defined by claim 4, further comprises steps of:

obtaining a full-charge capacity correction coefficient based on a ratio of a change of said map charging index to a change of said accumulative charging index; and

multiplying said full-charge capacity correction coefficient with said temporary full-charge capacity to obtain said corrected full-charge capacity.

19. The battery charging condition detecting method defined by claim 4, further comprises a step of correcting map data corresponding to said map charging index by multiplying a residual voltage ratio, said residual voltage ratio representing a degree of actual change of said first battery voltage.

20. The battery charging condition detecting method defined by claim 4, further comprises steps of:

detecting a plurality of discharge currents and corresponding battery voltages when said battery is in said predetermined discharging operation;

prohibiting said step of detecting said plurality of discharge currents and said corresponding battery voltages when said battery is subjected to a transitory charging phenomenon under said predetermined discharging operation until a momentarily charged capacity is canceled by a succeeding discharge capacity;

obtaining an internal resistance of said battery by statistically processing said plurality of discharge currents and said corresponding battery voltages detected; and

estimating a battery voltage corresponding to a given discharge current based on said internal resistance.

21. The battery charging condition detecting method defined by claim 5, further comprises a step of correcting map data corresponding to said map charging index by multiplying a residual voltage ratio, said residual voltage ratio representing a degree of actual change of said first battery voltage.

22. The battery charging condition detecting method defined by claim 5, further comprises steps of:

detecting a plurality of discharge currents and corresponding battery voltages when said battery is in said predetermined discharging operation;

prohibiting said step of detecting said plurality of discharge currents and said corresponding battery voltages when said battery is subjected to a transitory charging phenomenon under said predetermined discharging operation until a momentarily charged capacity is canceled by a succeeding discharge capacity;

obtaining an internal resistance of said battery by statistically processing said plurality of discharge currents and said corresponding battery voltages detected; and

estimating a battery voltage corresponding to a given discharge current based on said internal resistance.

23. The battery charging condition detecting method defined by claim 3, further comprises a step of calculating a deterioration factor of said battery by dividing said corrected full-charge capacity by said nominal capacity of said battery.

24. The battery charging condition detecting method defined by claim 4, further comprises a step of calculating a deterioration factor of said battery by dividing said corrected full-charge capacity by a nominal capacity of said battery.

25. The battery charging condition detecting method defined by claim 5, further comprises steps of:

obtaining a full-charge capacity correction coefficient based on a ratio of a change of said map charging index to a change of said accumulative charging index; and

multiplying said full-charge capacity correction coefficient with said temporary full-charge capacity to obtain said corrected full-charge capacity.

26. The battery charging condition detecting method defined by claim 6, further comprises a step of correcting map data corresponding to said map charging index by multiplying a residual voltage ratio, said residual voltage ratio representing a degree of actual change of said first battery voltage.