System for measuring state of charge of storage battery

• US 4,377,787 A
• Filed: 08/08/1980
• Issued: 03/22/1983
• Est. Priority Date: 08/14/1979
• Status: Expired due to Term

• Current Assignee: Hitachi Denshi Kabushiki Kaisha, Hitachi, Ltd., Nippon Hoso Kyokai, Shin-Kobe Electric Machinery Company Limited (Resonac Holdings Corp.)
• Original Assignee: Hitachi Denshi Kabushiki Kaisha, Hitachi, Ltd., Nippon Hoso Kyokai, Shin-Kobe Electric Machinery Company Limited (Resonac Holdings Corp.)
• Inventors: Murakami, Keinosuke, Ukigaya, Fumio, Noguchi, Hiroshi, Yamamoto, Hiroaki, Sasaki, Noriyoshi, Wakui, Kotaro, Ohnishi, Kazunori, Kikuoka, Takao, Kawamura, Gou
• Primary Examiner(s): Tokar, Michael J.
• Application Number:
  US06/176,356
• Time in Patent Office: 956 Days
• Field of Search: 324/425-428, 324/429, 324/430, 324/431, 324/433, 320/48
• US Class Current: 324/431
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/3832 without measurement of battery voltage

Abstract

A system for measuring the state of charge of a storage battery is disclosed which corrects charging and discharge electrical quantities of the battery in view of temperature and charging efficiency of the battery, and the like to precisely measure the state of charge thereof by digital-operation. There is also disclosed a system correcting, by digital-operation, the variation in capacity of the battery due to the variation in life of the battery and/or the self-discharge thereof as well, to thereby measure the state of charge with higher precision.

Claims

1. A system for measuring the state of charge of a storage battery comprising:

an electrical quantity detecting section for detecting the quantity of electricity charged to said storage battery and the quantity of electricity discharged therefrom, and outputting said detected electrical quantities as digital signals;

a temperature detecting section for detecting a temperature of said storage battery and outputting said detected temperature as a digital signal;

a memory means including a first memory having at least data on the discharge capacity of said storage battery at said detected temperature with respect to the discharge capacity of said storage battery at a standard temperature stored therein, a second memory having data on the charging efficiency of said storage battery in relation to a charging rate of said storage battery and said detected temperature stored therein, and a third memory having operational equations stored therein which are necessary for calculating at least one of an effective electrical quantity which said storage battery can discharge and an effective time which said storage battery can discharge an effective quantity of electricity based on said detected electrical quantities and detected temperature of said storage battery;

a digital-operation processing section for calculating at least one of said effective electrical quantity and said effective time by digital-operation based on said output signals of said electrical quantity detecting section and said temperature detecting section, and said data and operational equations stored in said memory means; and

an indicating section for indicating at least one of said effective electrical quantity and said effective time so calculated.

2. A system for measuring the state of charge of a storage battery as defined in claim 1, wherein said temperature detecting section comprises a temperature detector disposed adjacent to said storage battery and an analog-digital converter acting to convert an output of said temperature detector into said digital signal.

3. A system for measuring the state of charge of a storage battery as defined in claim 2, wherein said electrical quantity detecting section comprises an electrical quantity detector for integrating a charging current and a discharge current of said storage battery to detect said charging electrical quantity and discharge electrical quantity of said storage battery, respectively, and an analog-digital converter for converting outputs of said electrical quantity detector into said digital signals.

4. A system for measuring the state of charge of a storage battery as defined in claim 3, wherein said temperature detector and electrical quantity detector continuously operate, and said analog-digital converters, digital-operation processing section and memory means intermittently operate.

5. A system for measuring the state of charge of a storage battery as defined in claim 2, wherein said electrical quantity detecting section comprises a current detector for detecting a charging current and a discharge current of said storage battery, an analog-digital converter for converting outputs of said electrical quantity detector into said digital signals, and an operation means for integrating outputs of said analog-digital converter as a function of time.

6. A system for measuring the state of charge of a storage battery as defined in claim 5, wherein said temperature detector and current detector continuously operate;

and said analog-digital converters, operation means, digital-operation processing section and memory means intermittently operate.

7. A system for measuring the state of charge of a storage battery as defined in claim 5 or 6, wherein said digital-operation processing section also acts as said operation means.

8. A system for measuring the state of charge of a storage battery comprising:

an electrical quantity detecting section for detecting the quantity of electricity charged to said storage battery and the quantity of electricity discharged therefrom, and outputting said detected electrical quantities as digital signals;

a temperature detecting section for detecting a temperature of said storage battery and outputting said detected temperature as a digital signal;

a capacity measuring section for discharging electricity from said storage battery to a reference load connected to said storage battery to measure a capacity of said storage battery;

a memory means including a first memory having at least data on the discharge capacity of said storage battery at said detected temperature with respect to the discharge capacity of said storage battery at a standard temperature stored therein, a second memory having data on the charging efficiency of said storage battery in relation to a charging rate of said storage battery and said detected temperature stored therein, and a third memory having operational equations stored therein which are necessary for calculating at said detected temperature at least one of an effective electrical quantity which said storage battery can discharge and an effective time for which said storage battery can discharge an effective quantity of electricity based on said detected electrical quantities and detected temperature of said storage battery;

a digital-operation processing section for calculating at least one of said effective electrical quantity and effective time by digital-operation based on said output signals of said electrical quantity detecting section and temperature detecting section and said data and operational equations stored in said memory means;

an indicating section for indicating at least one of said effective electrical quantity and said effective time;

said digital-operation processing section acting to calculate said discharge capacity of said storage battery at said standard temperature based on said capacity of said storage battery measured by said capacity measuring section, said signal output by said temperature detecting section and said data stored in said memory means, and to allow said memory means to store said discharge capacity so calculated therein thereby correcting the variation in capacity of said storage battery due to the life variation thereof.

9. A system for measuring the state of charge of a storage battery as defined in claim 8, wherein said temperature detecting section comprises a temperature detector disposed adjacent to said storage battery and an analog-digital converter for converting an output of said temperature detector into said digital signal.

10. A system for measuring the state of charge of a storage battery as defined in claim 9, wherein said electrical quantity detecting section comprises an electrical quantity detector for integrating a charging current and a discharge current of said storage battery to detect said charging electrical quantity and discharge electrical quantity of said storage battery, respectively, and an analog-digital converter for converting outputs of said electrical quantity detector into said digital signals.

11. A system for measuring the state of charge of a storage battery as defined in claim 10, wherein said temperature detector and electrical quantity detector continuously operate, and said analog-digital converters, digital-operation processing section and memory means intermittently operate.

12. A system for measuring the state of charge of a storage battery as defined in claim 9, wherein said electrical quantity detecting section comprises a current detector for detecting a charging current and a discharge current of said storage battery, an analog-digital converter for converting outputs of said electrical quantity detector into said digital signals, and an operation means for integrating outputs of said analog-digital converter as a function of time.

13. A system for measuring the state of charge of a storage battery as defined in claim 12, wherein said temperature detector and current detector continuously operate;

and said analog-digital converters, operation means, digital-operation processing section and memory means intermittently operate.

14. A system for measuring the state of charge of a storage battery as defined in claim 12 or 13, wherein said digital-operation processing section also acts as said operation means.

15. A system for measuring the state of charge of a storage battery comprising:

an electrical quantity detecting section for detecting the quantity of electricity charged to said storage battery and the quantity of electricity discharged therefrom, and outputting said detected electrical quantities as digital signals;

a temperature detecting section for detecting a temperature of said storage battery and outputting said detected temperature as a digital signal;

a time detecting section for integrating a shelf time for which said storage battery is connected to neither a load nor a charger and converting said integrated time into a digital signal;

a memory means including a first memory having at least data on the discharge capacity of said storage battery at said detected temperature with respect to the discharge capacity of said storage battery at a standard temperature stored therein, a second memory having data on the charging efficiency of said storage battery in relation to a charging rate of said storage battery and said detected temperature stored therein, and a third memory having operational equations stored therein which are necessary for calculating at said detected temperature at least one of an effective electrical quantity which said storage battery can discharge and an effective time for which said storage battery can discharge an effective quantity of electricity based on said detected electrical quantities and detected temperature of said storage battery and having operational equations stored therein which are necessary for calculating an electrical quantity of said storage battery lost due to the self-discharge thereof during said shelf time to correct said effective electrical quantity and said effective time;

a digital-operation processing section for obtaining the correction in variation of discharge capacity of said storage battery due to said self-discharge based on said output signals of said electrical quantity detecting section and temperature detecting section, said signal output by said time detecting section, and said data and operational equations stored in said memory means to calculate at least one of said effective electrical quantity and said effective time by digital-operation; and

an indicating section for indicating at least one of said effective electrical quantity and said effective time.

16. A system for measuring the state of charge of a storage battery as defined in claim 15, wherein said temperature detecting section comprises a temperature detector disposed adjacent to said storage battery and an analog-digital converter for converting an output of said temperature detector into said digital signal.

17. A system for measuring the state of charge of a storage battery as defined in claim 16, wherein said electrical quantity detecting section comprises an electrical quantity detector for integrating a charging current and a discharge current of said storage battery to detect said charging electrical quantity and discharge electrical quantity of said storage battery, respectively, and an analog-digital converter for converting outputs of said electrical quantity detector into said digital signals.

18. A system for measuring the state of charge of a storage battery as defined in claim 17, wherein said temperature detector and electrical quantity detector continuously operate, and said analog-digital converters, digital-operation processing section and memory means intermittently operate.

19. A system for measuring the state of charge of a storage battery as defined in claim 16, wherein said electrical quantity detecting section comprises a current detector for detecting a charging current and a discharge current of said storage battery, an analog-digital converter for converting outputs of said electrical quantity detector into said digital signals, and an operation means for integrating outputs of said analog-digital converter as a function of time.

20. A system for measuring the state of charge of a storage battery as defined in claim 19, wherein said temperature detector and current detector continuously operate;

and said analog-digital converters, operation means, digital-operation processing section and memory means intermittently operate.

21. A system for measuring the state of charge of a storage battery as defined in claim 19 or 20, wherein said digital-operation processing section also acts as said operation means.

22. A system for measuring the state of charge of a storage battery comprising:

an electrical quantity detecting section for detecting the quantity of electricity charged to said storage battery and the quantity of electricity discharged therefrom, and outputting said detected electrical quantities as digital signals;

a temperature detecting section for detecting the temperature of said storage battery and outputting said detected temperature as a digital signal;

a capacity measuring section for discharging electricity from said storage battery to a reference load connected to said storage battery to measure the capacity of said storage battery;

a time detecting section for integrating a shelf time for which said storage battery is connected to neither a load nor a charger and converting said integrated time into a digital signal;

a memory means including a first memory having at least data on the discharge capacity of said storage battery at said detected temperature with respect to the discharge capacity of said storage battery at a standard temperature stored therein, a second memory having data on the charging efficiency of said storage battery in relation to a charging rate of said storage battery and said detected temperature stored therein, and a third memory having operational equations stored therein which are necessary for calculating at said detected temperature at least one of a useful electrical quantity which said storage battery can discharge and a useful time for which said storage battery can discharge a useful quantity of electricity and having operational equations stored therein which are necessary for calculating an electrical quantity of said storage battery lost due to the self-discharge thereof during said shelf time to correct said useful electrical quantity and said useful time;

a digital-operation processing section for obtaining the correction in variation of discharge capacity of said storage battery due to said self-discharge based on said output signals of said electrical quantity detecting section and said temperature detecting section, said capacity of said storage battery measured by said capacity measuring section, said signal output by said time detecting section, and said data and operational equations stored by said memory means to calculate at least one of said useful electrical quantity and said useful time by digital-operation;

an indicating section for indicating at least one of said useful electrical quantity and said useful time;

said digital-operation processing section acting to calculate said discharge capacity of said storage battery at said standard temperature based on said capacity of said storage battery measured by said capacity measuring section, said temperature detected by said temperature detecting section and said data stored by said memory means, and to allow said memory means to store said calculated discharged capacity therein, thereby correcting the variation of discharge capacity of said storage battery due to the life variation thereof.

23. A system for measuring the state of charge of a storage battery as defined in claim 22, wherein said temperature detecting section comprises a temperature detector disposed adjacent to said storage battery and an analog-digital converter for converting an output of said temperature detector into said digtial signal.

24. A system for measuring the state of charge of a storage battery as defined in claim 23, wherein said electrical quantity detecting section comprises an electrical quantity detector for integrating a charging current and a discharge current of said storage battery to detect said charging electrical quantity and discharge electrical quantity of said storage battery, respectively, and an analog-digital converter for converting outputs of said electrical quantity detector into said digital signals.

25. A system for measuring the state of charge of a storage battery as defined in claim 24, wherein said temperature detector and electrical quantity detector continuously operate, and said analog-digital converters, digital-operation processing section and memory means intermittently operate.

26. A system for measuring the state of charge of a storage battery as defined in claim 25, wherein said electrical quantity detecting section comprises a current detector for detecting a charging current and a discharge current of said storage battery, an analog-digital converter for converting outputs of said electrical quantity detector into said digital signals, and an operation means for integrating outputs of said analog-digital converter as a function of time.

27. A system for measuring the state of charge of a storage battery as defined in claim 26, wherein said temperature detector, electrical quantity detector and time detecting section continuously operate;

and said analog-digital converters, operation means, digital-operation processing section and memory means intermittently operate.

28. A system for measuring the state of charge of a storage battery as defined in claim 26 or 27, wherein said digital-operation processing section also acts as said operation means.