METHOD AND SYSTEM FOR DETERMINING A STATE OF CHARGE OF A BATTERY

• US 20110166811A1
• Filed: 03/15/2011
• Published: 07/07/2011
• 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: VERBRUGGE, Mark W., KOCH, Brian J., CONELL, Robert S., MEISNER, Gregory P.
• Granted Patent: US 8,212,519 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• 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. An automotive drive system comprising:

an electric motor;

a battery coupled to the electric motor;

a magnetic field generator configured to subject the battery to a predetermined magnetic field such that the battery and the magnetic field generator jointly create a resultant magnetic field;

a magnetically responsive component configured to generate an electromagnetic response to the resultant magnetic field; and

a processor in operable communication with the magnetically responsive component and configured to;

detect the electromagnetic response; and

determine a state of charge of the battery based on the electromagnetic response.

2. The automotive drive system of claim 1, wherein the electromagnetic response within the magnetically responsive component is a current.

3. The automotive drive system of claim 2, wherein the battery is a lithium ion battery.

4. The automotive drive system of claim 2, wherein the magnetic field generator comprises a first conductive wire wrapped around a first portion of the battery and the magnetically responsive component comprises a second conductive wire wrapped around a second portion of the battery.

5. The automotive drive system of claim 2, further comprising a memory in operable communication with the processor, the memory configured to store a table including electromagnetic response values and state of charge values associated with the electromagnetic response values.

6. A system comprising:

a battery;

a magnetic field generator configured to subject the battery to a predetermined magnetic field such that the battery and the magnetic field generator jointly create a resultant magnetic field; and

a magnetically responsive component configured to generate an electromagnetic response to the resultant magnetic field.

7. The system of claim 6, further comprising a processor configured to:

communicate with the magnetically responsive component;

detect the electromagnetic response; and

determine a state of charge of the battery based on the electromagnetic response.

8. The system of claim 6, wherein the electromagnetic response is a change in a magnetic susceptibility of the magnetically responsive component.

9. The system of claim 6, wherein the magnetically responsive component is a wire coil.

10. The system of claim 6, wherein the magnetically responsive component comprises a conductor configured to carry a current from a current source and receive substantially magnetic flux lines from a permanent magnet that are substantially perpendicular the magnetically responsive component.

11. The system of claim 7, wherein determining the state of charge of the battery comprises integrating a current flowing through the battery with respect to time.

12. The system of claim 10, wherein integrating the current flowing through the battery with respect to time comprises referring the electromagnetic response to a look up table.

13. An apparatus comprising:

a battery;

a magnetic sensor is one of located adjacent to and attached to the battery; and

a state of charge module in operable communication with the magnetic sensor, the state of charge module being configured to;

subject the battery to a predetermined magnetic field such that the battery and the state of charge module jointly create a resultant magnetic field; and

to detect an electromagnetic response to the predetermined magnetic field.

14. The apparatus of claim 13, wherein the predetermined magnetic field is applied by a permanent magnet.

15. The apparatus of claim 13, wherein the state of charge module comprises:

an output amplifier;

a first conductive winding configured to induce the predetermined magnetic field in the battery by conducting a first current flow;

a second conductive winding configured to conduct a second current flow induced in the second conductive winding by the resultant magnetic field; and

a control circuit configured to adjust the first current flow and the second current flow to produce a balanced input to the output amplifier.

16. The apparatus of claim 15, wherein the first conductive winding and the second conductive winding are wound around the battery.

17. The apparatus of claim 15, wherein the first conductive winding at least partially overlaps the second conductive winding.

18. The apparatus of claim 15, wherein the control circuit comprises a variable inductor connected in series with the first conductive winding and the second conductive winding.

19. The apparatus of claim 18, wherein the control circuit comprises a variable resistor connected in parallel with the second conductive winding and the variable inductor.

20. The apparatus of claim 19, wherein the output amplifier receives an input from the variable resistors.