Method and circuitry to calculate the state of charge of a battery/cell

• US 9,035,621 B2
• Filed: 07/02/2014
• Issued: 05/19/2015
• Est. Priority Date: 06/24/2010
• Status: Active Grant

• Current Assignee: Qnovo, Inc.
• Original Assignee: Qnovo, Inc.
• Inventors: Berkowitz, Fred, Maluf, Nadim, Ghantous, Dania
• Primary Examiner(s): Tso, Edward
• Assistant Examiner(s): Boateng, Alexis A
• Application Number:
  US14/322,863
• Publication Number:
  US 20140312912A1
• Time in Patent Office: 321 Days
• Field of Search: 320/139, 320/141, 320/129, 320/145, 320/151, 320/137, 320/148, 320/157, 320/125, 320/133, 320/127, 320/128, 320/155, 320/156
• US Class Current: 320/139
• 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 adapt the charging of a battery using data which is representative of an overpotential or relaxation time (full or partial) of the battery. In another aspect the present inventions are directed to techniques and/or circuitry to calculate data which is representative of an overpotential or relaxation time (full or partial) of the battery. In yet another aspect the present inventions are directed to techniques and/or circuitry to calculate data which is representative of a state of charge of the battery using an overpotential or relaxation time (full or partial) of the battery.

Claims

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

measuring a first voltage at the terminals of the battery after terminating a signal applied to the terminals of the battery;

determining data which is representative of a full relaxation time of the battery using the first voltage, wherein the full relaxation time is an amount of time corresponding to when the voltage at the terminals of the battery decays to a voltage which correlates to an equilibrium voltage of the battery;

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

outputting the state of charge of the battery.

2. The method of claim 1 wherein using the first voltage to determine the data which is representative of a full relaxation time of the battery includes using an amount of time associated with the decay of the voltage at the terminals of the battery to at least the first voltage.

3. The method of claim 2 wherein determining a state of charge of the battery using the data which is representative of the full relaxation time includes (i) determining an initial state of charge of the battery and (ii) adjusting or correcting the initial state of charge of the battery using (a) the data which is representative of the full relaxation time or (b) the state of charge of the battery determined using the data which is representative of the full relaxation time.

4. The method of claim 1 further including applying the signal to the terminals of the battery, wherein the signal includes a plurality of charge signal pulses.

5. The method of claim 4 wherein the plurality of charge signal pulses of the signal is generated during a single recharge cycle.

6. The method of claim 1 wherein determining a state of charge of the battery using the data which is representative of the full relaxation time includes (i) determining an initial state of charge of the battery and (ii) adjusting or correcting the initial state of charge of the battery using (a) the data which is representative of the full relaxation time or (b) the state of charge of the battery determined using the data which is representative of the full relaxation time.

7. The method of claim 1 further including:

applying the signal to the terminals of the battery;

adapting one or more characteristics of the signal based on or using data which is representative of the state of charge of the battery, including changing (i) an amplitude of the signal and/or (ii) a pulse width of the signal.

8. The method of claim 1 wherein the first voltage is a voltage which is constant or substantially constant after terminating the signal.

9. The method of claim 1 wherein the first voltage is a voltage at which the full relaxation time is capable of being determined based on or using a form, shape and/or rate of decay of the voltage at the terminals of the battery after terminating the signal.

10. The method of claim 1 further including:

computing a rate of decay of the voltage at the terminals of the battery after terminating the signal, and

wherein determining a state of charge of the battery further includes using the computed rate of decay of the voltage at the terminals to determine the state of charge of the battery.

11. 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 charge signal to the terminals of the battery;

terminating the charge signal;

measuring a first voltage at the terminals of the battery after terminating the charge signal;

determining data which is representative of a relaxation time of the battery using an amount of time associated with a decay of the voltage at the terminals of the battery to at least the first voltage, wherein;

(i) the relaxation time is an amount of time corresponding to when, in response to terminating the charge signal, the voltage at the terminals of the battery decays to at least the first voltage, and (ii) the first voltage correlates to an equilibrium voltage of the battery; and

calculating a state of charge of the battery using data which is representative of the relaxation time of the battery.

12. The method of claim 11 wherein the relaxation time is a full relaxation time.

13. The method of claim 12 wherein the first voltage is a voltage at which the relaxation time is capable of being determined based on or using the form or shape of decay of the voltage at the terminals of the battery after terminating the charge signal.

14. The method of claim 12 wherein the first voltage is a voltage at which the relaxation time is capable of being determined based on or using the rate of decay of the voltage at the terminals of the battery after terminating the charge signal.

15. The method of claim 12 wherein the first voltage is a voltage which is constant or substantially constant after terminating the charge signal.

16. The method of claim 12 wherein the first 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 charge signal.

17. The method of claim 11 wherein the relaxation time is a partial relaxation time.

18. The method of claim 11 further including:

computing a rate of decay of the voltage at the terminals of the battery after terminating the charge signal, and

wherein calculating a state of charge of the battery further includes using the computed rate of decay of the voltage at the terminals to calculate the state of charge of the battery.

19. The method of claim 11 further including:

adapting one or more characteristics of the charge signal based on or using data which is representative of the state of charge of the battery, including changing (i) an amplitude of the charge signal and/or (ii) a pulse width of the charge signal.

20. The method of claim 11 wherein determining a state of charge of the battery using the data which is representative of the relaxation time includes (i) determining an initial state of charge of the battery and (ii) adjusting or correcting the initial state of charge of the battery using (a) the data which is representative of the relaxation time or (b) the state of charge of the battery determined using the data which is representative of the relaxation time.

21. 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 (i) generate and apply the charge signal to the terminals of the battery and (ii) terminate the charge signal;

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

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 using the first voltage, wherein;

the relaxation time is an amount of time corresponding to when, after terminating the charge signal, the voltage at the terminals of the battery decays to at least the first voltage; and

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

22. The apparatus of claim 21 wherein the control circuitry is configured to determine data which is representative of a relaxation time based on or using the rate of decay of the voltage at the terminals of the battery after termination of the charge signal.

23. The apparatus of claim 21 wherein the relaxation time is a full relaxation time and the first voltage correlates to an equilibrium voltage of the battery.

24. The apparatus of claim 21 wherein using the first voltage to determine the data which is representative of a relaxation time of the battery includes using an amount of time associated with the decay of the voltage at the terminals of the battery to at least the first voltage.

25. The apparatus of claim 21 wherein the first voltage is a voltage which is constant or substantially constant after termination of the charge signal.

26. The apparatus of claim 21 wherein the first 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 after termination of the charge signal.

27. The apparatus of claim 21 wherein the control circuitry generates one or more control signals using data which is representative of the state of charge of the battery.

28. The apparatus of claim 21 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.

29. The apparatus of claim 21 wherein the control circuitry is further configured to determine (i) an initial state of charge of the battery and (ii) adjust or correct the initial state of charge of the battery using (a) the data which is representative of the relaxation time or (b) data which is representative of a state of charge of the battery using the data which is representative of the relaxation time.

30. The apparatus of claim 21 wherein the control circuitry determines data which is representative of a relaxation time of the battery based on or using a rate of decay of the voltage at the terminals of the battery after to the termination of the charge signal.