Method and Circuitry to Calculate the State of Charge of a Battery/Cell

• US 20110316548A1
• Filed: 06/24/2011
• Published: 12/29/2011
• Est. Priority Date: 06/24/2010
• Status: Active Grant

• Current Assignee: Qnovo, Inc.
• Original Assignee: Qnovo, Inc.
• Inventors: Ghantous, Dania, Berkowitz, Fred, Maluf, Nadim
• Granted Patent: US 8,791,669 B2
• Time in Patent Office: Days
• US Class Current: 324/427
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: G01R 31/388 involving voltage measurements
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• 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: H01M 50/569 Constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals battery terminal connectors with integrated measuring arrangements G01R31/364
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

The present inventions, in one aspect, are directed to techniques and/or circuitry to determine the state of charge of a battery/cell using data which is representative of a partial relaxation time of the battery/cell. In another aspect the present inventions are directed to techniques and/or circuitry to determine the state of charge of a battery/cell using data which is representative of an overpotential or full relaxation time of the battery/cell. In yet another aspect the present inventions are directed to techniques and/or circuitry to adaptively charge a battery/cell using data which is representative of a state of charge of the battery/cell.

Claims

1. A method to determine a state of charge of a battery, wherein the battery includes at least two terminals, the method comprising:

applying a signal to the terminals of the battery, wherein the signal includes a plurality of pulses;

measuring a voltage at the terminals of the battery;

determining data which is representative of a relaxation time of the battery, wherein the relaxation time is an amount of time corresponding to when, in response to a pulse of the signal, the voltage at the terminals of the battery/cell decays to at least a predetermined voltage;

determining data which is representative of a state of charge of the battery using the data which is representative of the relaxation time; and

displaying the data which is representative of the state of charge of the battery.

2. The method of claim 1 wherein the predetermined voltage is a voltage which is less than or equal to 10% of a peak of a change in the voltage at the terminals of the battery due to the pulse of the signal.

3. The method of claim 1 further including adapting one or more characteristics of the signal based on or using data which is representative of the state of charge of the battery, wherein adapting one or more characteristics of the signal based on or using data which is representative of the relaxation time includes changing the amount of time between successive pulses of the plurality of pulses of the signal.

4. The method of claim 1 further including adapting one or more characteristics of the signal based on or using data which is representative of the state of charge of the battery, wherein adapting one or more characteristics of the signal based on or using data which is representative of the relaxation time includes changing the amplitude and/or duration of at least one pulse of the signal.

5. The method of claim 1 wherein the pulse of the signal is a charge pulse or discharge pulse.

6. The method of claim 5 further including adapting one or more characteristics of the signal based on or using data which is representative of the state of charge of the battery, wherein adapting one or more characteristics of the signal based on or using data which is representative of the state of charge of the battery further includes changing:

(i) an amplitude and/or a pulse width of at least one pulse of the signal, and/or (ii) a length of time of a rest period between two successive pulses of the plurality of pulses of the signal.

7. The method of claim 6 wherein the two successive pulses are a discharge pulse followed by a charge pulse.

8. The method of claim 1 wherein the relaxation time is a partial relaxation time or full relaxation time.

9. The method of claim 1 wherein the predetermined voltage is a voltage which is constant or substantially constant after applying the pulse and before applying another and immediately subsequent pulse.

10. The method of claim 1 wherein the relaxation time is a full relaxation time and the predetermined voltage is a voltage which is greater than 50% of the peak of the change in the voltage at the terminals of the battery due to the pulse.

11. The method of claim 1 wherein the predetermined voltage is a voltage at which the relaxation time is capable of being determined based on or using the form, shape and/or rate of decay of the voltage at the terminals of the battery due to the pulse of the signal.

12. An apparatus to determine a state of charge of a battery, wherein the battery includes at least two terminals, the apparatus comprising:

signal generation circuitry, coupled to the battery, to generate a signal and apply the signal to the terminals of the battery, wherein the signal includes a pulse;

measurement circuitry, coupled to the battery, to measure a voltage at the terminals of the battery;

control circuitry, coupled to the measurement circuitry to receive data which is representative of the voltage at the terminals of the battery, wherein the control circuitry is configured to;

determine data which is representative of a relaxation time of the battery, wherein the relaxation time is an amount of time corresponding to when, in response to the pulse of the signal, the voltage at the terminals of the battery/cell decays to at least a predetermined voltage; and

determine data which is representative of a state of charge of the battery using or based on the relaxation time.

13. The apparatus of claim 12 wherein the relaxation time is a partial relaxation time or a full relaxation time.

14. The apparatus of claim 12 wherein the predetermined voltage is a voltage which is less than or equal to 10% of the peak of the change in the voltage at the terminals of the battery due to the pulse.

15. The apparatus of claim 12 wherein the predetermined voltage is a voltage which is constant or substantially constant after application of the pulse and before application of another and immediately subsequent pulse.

16. The apparatus of claim 12 wherein the predetermined voltage is a voltage at which the relaxation time is capable of being determined based on or using the form, shape and/or rate of decay of the voltage at the terminals of the battery due to the pulse of the signal.

17. The apparatus of claim 12 wherein the control circuitry generates one or more control signals using data which is representative of a state of charge of the battery.

18. A method to calculate and output a state of charge of a battery, wherein the battery includes at least two terminals, the method comprising:

applying a pulse to the terminals of the battery;

measuring a voltage at the terminals of the battery;

determining data which is representative of a relaxation time of the battery, wherein the relaxation time is an amount of time corresponding to when, in response to the pulse, the voltage at the terminals of the battery/cell decays to at least a predetermined voltage;

calculating a state of charge of the battery using data which is representative of (i) the relaxation time of the battery and (ii) a voltage at the terminals of the battery; and

outputting the state of charge of the battery.

19. The method of claim 18 wherein the relaxation time is a partial relaxation time and the predetermined voltage is a voltage which is less than or equal to 10% of a peak of a change in the voltage at the terminals of the battery due to the pulse.

20. The method of claim 18 wherein the pulse is a charge pulse or is a discharge pulse.

21. The method of claim 18 wherein the relaxation time is a partial relaxation time or full relaxation time.

22. The method of claim 18 wherein the predetermined voltage is a voltage which is constant or substantially constant after applying the pulse and before applying of another and immediately subsequent pulse.

23. The method of claim 18 wherein the relaxation time is a full relaxation time and the predetermined voltage is a voltage which is greater than 50% of the peak of the change in the voltage at the terminals of the battery due to the pulse.

24. The method of claim 18 wherein the predetermined voltage is a voltage at which the relaxation time is capable of being determined based on or using the form, shape and/or rate of decay of the voltage at the terminals of the battery due to the pulse.

25. An apparatus to determine a state of charge of a battery, wherein the battery includes at least two terminals, the apparatus comprising:

signal generation, coupled to the battery, to generate a pulse and apply the pulse to the terminals of the battery;

measurement circuitry, coupled to the battery, to measure a voltage at the terminals of the battery; and

control circuitry, coupled to the measurement circuitry, wherein the control circuitry is configured to;

determine data which is representative of a relaxation time of the battery, wherein the relaxation time is an amount of time corresponding to when, in response to the pulse, the voltage at the terminals of the battery/cell decays to at least a predetermined voltage; and

determine a state of charge of the battery using data which is representative of (i) the relaxation time of the battery and (ii) a voltage at the terminals of the battery.

26. The apparatus of claim 25 wherein the relaxation time is a partial relaxation time or a full relaxation time.

27. The apparatus of claim 25 wherein the predetermined voltage is a voltage which is less than or equal to 10% of the peak of the change in the voltage at the terminals of the battery due to the pulse.

28. The apparatus of claim 25 wherein the predetermined voltage is a voltage which is constant or substantially constant after application of the pulse and before application of another and immediately subsequent pulse.

29. The apparatus of claim 25 wherein the predetermined voltage is a voltage at which the relaxation time is capable of being determined based on or using the form, shape and/or rate of decay of the voltage at the terminals of the battery due to the pulse.

30. The apparatus of claim 25 further including a display, coupled to the control circuitry, to receive and display data which is representative of the state of charge of the battery.