SYSTEM AND METHOD FOR PROGNOSIS OF BATTERIES

• US 20140176147A1
• Filed: 12/26/2012
• Published: 06/26/2014
• Est. Priority Date: 12/26/2012
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Wiegman, Herman Lucas Norbert, James, David Eugene
• Granted Patent: US 9,465,080 B2
• Time in Patent Office: Days
• US Class Current: 324/434
• CPC Class Codes: G01R 31/378 specially adapted for the type of battery or accumulator
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements

Abstract

In accordance with one aspect of the present technique, a method is disclosed. The method includes identifying a first change in an excitation direction of a group of cells and determining a first set of characteristics of the group of cells corresponding to the first change. The method also includes identifying a second change in the excitation direction of the group of cells and determining a second set of characteristics of the group of cells corresponding to the second change. The second change in the excitation direction is opposite to the first change in the excitation direction. The method further includes determining a number of functional cells from the group of cells based on the first and the second set of characteristics.

Claims

1. A method, comprising:

identifying a first change in an excitation direction of a group of cells;

determining a first set of characteristics of the group of cells corresponding to the first change;

identifying a second change in the excitation direction of the group of cells, wherein the second change in the excitation direction is opposite to the first change in the excitation direction;

determining a second set of characteristics of the group of cells corresponding to the second change; and

determining a number of functional cells from the group of cells based on the first and the second set of characteristics.

2. The method of claim 1, wherein the first set of characteristics comprises a first voltage and a first current corresponding to the first change and the second set of characteristics includes a second current and a second voltage corresponding to the second change.

3. The method of claim 1, further comprising:

calculating a first resistance of the group of cells based on the first set of characteristics and an open circuit voltage of the group of cells; and

calculating a second resistance of the group of cells based on the second set of characteristics and the open circuit voltage of the group of cells.

4. The method of claim 3, further comprising calculating a difference between the first resistance and the second resistance.

5. The method of claim 4, further comprising:

retrieving an initial number of cells in the group of cells from a memory; and

modifying the initial number of cells based on the determined number of functional cells to reduce the difference below a resistance threshold value.

6. The method of claim 1, further comprising:

calculating a number of non-functional cells from the group of cells based on the determined number of functional cells;

comparing the number of non-functional cells with a fault threshold value; and

determining that the group of cells is in a fault state if the number of non-functional cells exceeds the fault threshold value.

7. The method of claim 6, further comprising disconnecting the group of cells in response to determining that the group of cells is in the fault state.

8. The method of claim 1, further comprising:

measuring a terminal current and a terminal voltage of the group of cells; and

determining the excitation direction of the group of cells based on at least one of the terminal current and the terminal voltage.

9. The method of claim 1, wherein the group of cells operates based on a first-in-first-out reaction principle, wherein a reaction resistance of the group of cells decreases to an offset level during the first and the second change in the excitation direction.

10. A system comprising:

at least one processor;

a direction module stored in a memory and executable by the at least one processor, the direction module for identifying a first change in an excitation direction of a group of cells, determining a first set of characteristics of the group of cells corresponding to the first change, identifying a second change in the excitation direction of the group of cells and determining a second set of characteristics of the group of cells corresponding to the second change, wherein the second change in the excitation direction is opposite to the first change in the excitation direction; and

a determination module stored in the memory and executable by the at least one processor, the determination module coupled to the direction module for determining a number of functional cells from the group of cells based on the first and the second set of characteristics.

11. The system of claim 10, wherein the first set of characteristics includes a first voltage and a first current corresponding to the first change and the second set of characteristics includes a second current and a second voltage corresponding to the second change.

12. The system of claim 10, further comprising a resistance module for calculating a first resistance of the group of cells based on the first set of characteristics and an open circuit voltage of the group of cells and calculating a second resistance of the group of cells based on the second set of characteristics and the open circuit voltage of the group of cells.

13. The system of claim 12, wherein the determination module further calculates a difference between the first resistance and the second resistance.

14. The system of claim 13, further comprising a control module for retrieving an initial number of cells in the group of cells from a memory and modifying the initial number of cells based on the determined number of functional cells to reduce the difference below a resistance threshold value.

15. The system of claim 10, further comprising a monitoring device communicatively coupled to the at least one processor, wherein the monitoring device is configured to measure a terminal current and a terminal voltage of the group of cells.

16. The system of claim 15, wherein the direction module further determines the excitation direction of the group of cells based on at least one of the terminal current and the terminal voltage.

17. A computer program product comprising a non-transitory computer readable medium encoding instructions that, in response to execution by at least one processor, cause the processor to perform operations comprising:

identifying a first change in an excitation direction of a group of cells;

determining a first set of characteristics of the group of cells corresponding to the first change;

identifying a second change in the excitation direction of the group of cells, wherein the second change in the excitation direction is opposite to the first change in the excitation direction;

determining a second set of characteristics of the group of cells corresponding to the second change; and

determining a number of functional cells from the group of cells based on the first and the second set of characteristics.

18. The computer program product of claim 17, wherein the first set of characteristics comprises a first voltage and a first current corresponding to the first change and the second set of characteristics includes a second current and a second voltage corresponding to the second change.

19. The computer program product of claim 17, further causing the processor to perform operations comprising:

calculating a first resistance of the group of cells based on the first set of characteristics and an open circuit voltage of the group of cells; and

calculating a second resistance of the group of cells based on the second set of characteristics and the open circuit voltage of the group of cells.

20. The computer program product of claim 19, further causing the processor to perform operations comprising calculating a difference between the first resistance and the second resistance.