Method and circuitry to determine the relaxation time of a battery/cell

• US 9,385,555 B2
• Filed: 09/11/2015
• Issued: 07/05/2016
• Est. Priority Date: 05/21/2010
• Status: Active Grant

• Current Assignee: Qnovo, Inc.
• Original Assignee: Qnovo, Inc.
• Inventors: Ghantous, Dania, Maluf, Nadim, Berkowitz, Fred
• Primary Examiner(s): TSO, EDWARD H
• Application Number:
  US14/851,921
• Publication Number:
  US 20150380957A1
• Time in Patent Office: 298 Days
• Field of Search: 320/127, 320/128, 320/133, 320/139, 320/141
• US Class Current: 1/1
• CPC Class Codes: G01R 31/36 Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/007184 in response to battery voltage gradient
• 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 adaptively charge a battery/cell using data which is representative of a change in terminal voltage of the battery/cell. In another aspect, the present inventions are directed to techniques and/or circuitry to adaptively charge a battery/cell using data which is representative of partial and/or full relaxation time of the battery/cell. In yet another aspect the present inventions are directed to techniques and/or circuitry to determine whether the data which is representative of partial and/or full relaxation time exceeds a predetermined range and/or is greater than a predetermined value.

Claims

1. A method of controlling at least one characteristic of a charging process for a battery having positive and negative terminals, the method comprising:

(a) measuring a terminal voltage between the terminals of the battery multiple times or continuously over a period of time;

(b) from the measurements of the terminal voltage in (a), determining a relaxation time of the battery; and

(c) based on the relaxation time determined in (b), controlling at least one characteristic of a charging process for the battery.

2. The method of claim 1, wherein the relaxation time is a full relaxation time.

3. The method of claim 1, wherein controlling the at least one characteristic of the charging process for the battery comprises adjusting the at least one characteristic so that the relaxation time is below a predetermined value and/or within a predetermined range.

4. The method of claim 3, wherein the predetermined value and/or predetermined range varies with state of charge of the battery and/or state of health of the battery.

5. The method of claim 1, wherein determining the relaxation time of the battery comprises determining from the measurements of the terminal voltage a period of time between an excitation signal applied to the battery terminals and a full or partial equilibrium state.

6. The method of claim 5, wherein the excitation signal comprises a charge pulse.

7. The method of claim 1, wherein determining the relaxation time of the battery comprises determining from the measurements of the terminal voltage a period of time for the terminal voltage to drop to a predetermined level and/or drop by a predetermined amount associated equilibrium in the battery.

8. The method of claim 1, wherein the at least one characteristic of the charging process for the battery are characteristics of a charge signal.

9. The method of claim 8, wherein the at least one characteristic is selected from the group consisting of an amplitude and/or a duration of the charge signal.

10. The method of claim 8, wherein the current signal comprises a plurality of charge pulses and a plurality of discharge pulses.

11. An apparatus to charge a battery including at least two terminals, the apparatus comprising:

current generation circuitry, coupled to the battery, to;

generate a current signal, and

apply the current signal to the battery;

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

control circuitry, coupled to the current generation circuitry and the measuring circuitry, and configured to (i) receive data which is representative of the measured voltage, and (ii) output one or more control signals to the current generation circuitry, wherein the control circuitry is further configured to;

(a) obtain a terminal voltage measured multiple times or continuously over a period of time,

(b) from the measurements of the terminal voltages obtained in (a), determining a relaxation time of the battery, and

(c) based on the relaxation time determined in (b), control at least one characteristic of the current signal.

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

13. The apparatus of claim 11, wherein the control circuitry is configured such that controlling the at least one characteristic of the current signal comprises adjusting the at least one characteristic so that the relaxation time is below a predetermined value and/or within a predetermined range.

14. The apparatus of claim 13, wherein the predetermined value and/or predetermined range varies with state of charge of the battery and/or state of health of the battery.

15. The apparatus of claim 11, wherein the control circuitry is configured such that determining the relaxation time of the battery comprises determining from the measurements of the terminal voltage a period of time between an excitation signal applied to the battery terminals and a full or partial equilibrium state.

16. The apparatus of claim 15, wherein the excitation signal comprises a charge pulse.

17. The apparatus of claim 11, wherein the control circuitry is configured such that determining the relaxation time of the battery comprises determining from the measurements of the terminal voltage a period of time for the terminal voltage to drop to a predetermined level and/or drop by a predetermined amount associated equilibrium in the battery.

18. The apparatus of claim 11, wherein the at least one characteristic is selected from the group consisting of an amplitude and/or a duration of the current signal.

19. The apparatus of claim 11, wherein the current signal comprises a plurality of charge pulses and a plurality of discharge pulses.