Method and Circuitry to Adjust, Correct and/or Compensate an SOC of a Battery based on Relaxation Time thereof

• US 20150219722A1
• Filed: 04/11/2015
• Published: 08/06/2015
• Est. Priority Date: 06/24/2010
• Status: Active Grant

• Current Assignee: Qnovo, Inc.
• Original Assignee: Qnovo, Inc.
• Inventors: Maluf, Nadim, Ghantous, Dania, Berkowitz, Fred
• Granted Patent: US 9,791,513 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 adjust, correct and/or compensate a state of charge of the battery using the data which is representative of the relaxation time (e.g., full relaxation time) of the battery. The techniques and/or circuitry may determine the data which is representative of a relaxation time based on or using: (i) the rate of decay of the voltage at the terminals of the battery after terminating application of the charge current to the battery, (ii) a voltage which is constant or substantially constant after termination of the charge current and/or (iii) an amount of time associated with the decay of the voltage at the terminals of the battery to at least a measured or predetermined voltage. Notably, the charge signal or current may include a plurality of pulses.

Claims

1. A method to determine data which is representative of 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 current applied to the terminals of the battery;

determining data which is representative of a relaxation time of the battery using the first voltage and a form, shape or rate of decay of the voltage of the battery after terminating application of the current, wherein the 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; and

determining data corresponding to a state of charge of the battery using the data which is representative of the relaxation time.

2. The method of claim 1 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.

3. The method of claim 2 wherein determining data corresponding to a state of charge of the battery using the data which is representative of the relaxation time includes adjusting or correcting a first state of charge of the battery using (a) the data which is representative of the relaxation time or (b) determining data corresponding to a state of charge of the battery.

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

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

6. The method of claim 1 further including:

applying the current to the terminals of the battery; and

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

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

8. The method of claim 1 wherein the first voltage is a voltage at which the 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 in response to and after terminating the current.

9. The method of claim 1 further including:

computing a rate of decay of the voltage at the terminals of the battery after terminating the current; and

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

10. A method to calculate an adjustment, correction or compensation of a state of charge of a battery, wherein the battery includes at least two terminals, the method comprising:

applying a charge current to the terminals of the battery;

terminating the charge current;

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

determining data which is representative of a relaxation time of the battery using the first voltage and a form, shape or rate of decay of the voltage of the battery after terminating the charge current, wherein the relaxation time is an amount of time corresponding to when, in response to terminating the charge current, the voltage at the terminals of the battery decays to an equilibrium voltage of the battery; and

adjusting, correcting or compensating a state of charge of the battery using the data which is representative of the relaxation time.

11. The method of claim 10 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 current.

12. The method of claim 10 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 current.

13. The method of claim 10 wherein the first voltage is a voltage which is constant or substantially constant after terminating the charge current.

14. The method of claim 10 further including:

determining a rate of decay of the voltage at the terminals of the battery after terminating the charge current; and

wherein adjusting, correcting or compensating a state of charge of the battery further includes using the computed rate of decay of the voltage at the terminals to adjust, correct or compensate a state of charge of the battery.

15. The method of claim 10 further including determining a first state of charge of the battery and wherein adjusting, correcting or compensating a state of charge of the battery includes adjusting, correcting or compensating the first state of charge of the battery using the data which is representative of the relaxation time.

16. 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 current to the battery and (ii) terminate application of the charge current to the battery;

measurement circuitry, coupled to the battery, to measure a first voltage at the terminals of the battery after terminating application of the charge current to 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 at least the first voltage, wherein the relaxation time is an amount of time corresponding to when, after terminating the charge current, the voltage at the terminals of the battery decays to at least the first voltage; and

adjusting, correcting or compensating a state of charge of the battery using the data which is representative of the relaxation time.

17. The apparatus of claim 16 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 terminating application of the charge current to the battery.

18. The apparatus of claim 16 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.

19. The apparatus of claim 16 wherein the first voltage is a voltage which is constant or substantially constant after termination of the charge current.

20. The apparatus of claim 16 wherein the control circuitry determines the data which is representative of a relaxation time of the battery using the first voltage and a form, shape or rate of decay of the voltage of the battery after terminating application of the charge current to the battery.