Method and system for determining a state of charge of a battery

• US 7,928,690 B2
• Filed: 11/29/2007
• Issued: 04/19/2011
• Est. Priority Date: 11/29/2007
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Conell, Robert S., Meisner, Gregory P., Koch, Brian J., Verbrugge, Mark W.
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): BOATENG, ALEXIS ASIEDUA
• Application Number:
  US11/947,466
• Publication Number:
  US 20090140742A1
• Time in Patent Office: 1,237 Days
• Field of Search: 320/134, 320/132, 320/107, 320/135, 320/136, 320/108, 320/124, 320/137, 320/149, 324/426
• US Class Current: 320/108
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: H01F 7/0273 Magnetic circuits with PM for magnetic field generation
• CPC Class Codes: H01F 7/0278 for generating uniform fields, focusing, deflecting electrically charged particles for magnetic separation by Lorentz force B03C1/023; specially adapted for NMR applications G01R33/383
• CPC Class Codes: H02J 7/32 for charging batteries from a charging set comprising a non-electric prime mover rotating at constant speed

Abstract

Methods and systems are provided for determining a state of charge of a battery. The battery is subjected to a predetermined magnetic field such that the battery and the predetermined magnetic field jointly create a resultant magnetic field. The resultant magnetic field is sensed. The state of charge of the battery is determined based on the resultant magnetic field.

Claims

1. A method for determining a state of charge of a battery comprising:

subjecting the battery to a predetermined magnetic field such that the battery and the predetermined magnetic field jointly create a resultant magnetic field;

sensing the resultant magnetic field; and

determining the state of charge of the battery based on the resultant magnetic field,

wherein the determining of the state of charge is further based on an integration of current flowing through the battery with respect to time, and the determining the state of charge of the battery comprises;

determining a magnetic portion of the state of charge based on the resultant magnetic field;

determining a current portion of the state of charge based on the integration of current; and

weighting the magnetic portion of the state of charge and the current portion of the state of charge such that, as the current flow through the battery increases, influence on the state of charge by the magnetic portion is decreased.

2. The method of claim 1, wherein the sensing of the resultant magnetic field comprises:

subjecting a magnetically responsive component to the resultant magnetic field; and

detecting an electromagnetic response within the magnetically responsive component.

3. The method of claim 2, wherein the electromagnetic response within the magnetically responsive component is a current, a voltage, an electric power, or a combination thereof.

4. The method of claim 3, further comprising generating the predetermined magnetic field.

5. The method of claim 4, wherein the generating of the predetermined magnetic field comprises:

wrapping a first conductive wire wrapped around at least a portion of the battery; and

conducting current through the first conductive wire.

6. The method of claim 5, wherein the magnetically responsive component is a second conductive wire wrapped around at least a portion of the battery.

7. The method of claim 4, wherein the generating of the predetermined magnetic field comprises positioning a permanent magnet within a predetermined distance of the battery.

8. The method of claim 7, wherein the magnetically responsive component is a Hall Effect sensor.

9. The method of claim 1, wherein the battery is an automotive battery.

10. The method of claim 1, wherein the battery is a lithium ion battery.

11. A method for determining a state of charge of an automotive battery comprising:

generating a predetermined magnetic field;

subjecting the battery to the predetermined magnetic field such that the battery and the predetermined magnetic field jointly create a resultant magnetic field;

subjecting a magnetically responsive component to the resultant magnetic field;

detecting an electromagnetic response within the magnetically responsive component; and

determining the state of charge of the battery based on the electromagnetic response,

wherein the determining of the state of charge is further based on an integration of current flowing through the battery with respect to time, and the determining the state of charge of the battery further comprises;

determining a magnetic portion of the state of charge based on the electromagnetic response;

determining a current portion of the state of charge based on the integration of current; and

weighting the magnetic portion of the state of charge and the current portion of the state of charge such that, as the current flow through the battery increases, influence on the state of charge by the magnetic portion is decreased.

12. The method of claim 11, wherein the battery is a lithium ion battery.

13. The method of claim 12, wherein the determining the state of charge of the automotive battery is not based on a voltage of the automotive battery.

14. The method of claim 13, wherein the electromagnetic response within the magnetically responsive component is a current, a voltage, an electric power, or a combination thereof.

15. A method for determining a state of charge of an automotive battery comprising:

generating a predetermined magnetic field;

subjecting the battery to the predetermined magnetic field such that the battery and the predetermined magnetic field jointly create a resultant magnetic field;

subjecting a Hall Effect sensor to the resultant magnetic field;

detecting an electromagnetic response within the Hall Effect sensor; and

determining the state of charge of the battery based on the electromagnetic response.

16. The method of claim 15, wherein the automotive battery is a lithium ion battery.

17. The method of claim 16, wherein the determining of the state of charge is further based on an integration of current flowing through the battery with respect to time, and the determining the state of charge of the battery further comprises:

determining a magnetic portion of the state of charge based on the electromagnetic response;

determining a current portion of the state of charge based on the integration of current; and

weighting the magnetic portion of the state of charge and the current portion of the state of charge such that as the current flow through the battery increases, influence on the state of charge by the magnetic portion is decreased.

18. The method of claim 17, wherein the generating of the predetermined magnetic field comprises positioning a permanent magnet within a predetermined distance of the battery.

19. The method of claim 18, wherein the electromagnetic response within the magnetically responsive component is a current, a voltage, an electric power, or a combination thereof.