Systems, Methods and Circuits for Determining Micro-Short

• US 20090099799A1
• Filed: 10/10/2007
• Published: 04/16/2009
• Est. Priority Date: 10/10/2007
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Elder, Garry, Qian, Jinrong, Barsoukov, Yevgen P.
• Granted Patent: US 8,049,465 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: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Various systems and methods for determining micro-shorts are disclosed. For example, some embodiments of the present invention provide battery systems including a determination of potential micro-shorts based on rate of change of state of charge. Such battery systems include: a battery, a processor, and a computer readable medium. The computer readable medium includes instructions executable by the processor to: determine a rate of change of the state of charge of the battery; compare the rate of change of the state of charge of the battery against a threshold; and indicate a potential failure where the result of the comparison is beyond the threshold.

Claims

1. A method for predicting battery failure, the method comprising:

providing a battery;

determining a rate of change of the state of charge of the battery;

comparing the rate of change of the state of charge of the battery against a threshold; and

determining a potential failure condition based on a result of the comparison of the rate of change of the state of charge of the battery with the threshold.

2. The method of claim 1, wherein the battery is a single cell battery, and wherein the method further comprises:

adjusting the rate of change of the state of charge of the battery to compensate for external current.

3. The method of claim 1, wherein the battery is a multi-cell battery having at least a first cell and a second cell, wherein determining the rate of change of the state of charge of the battery includes determining the rate of change of the state of charge of the first cell and determining the rate of change of the state of charge of the second cell, and wherein the method further comprises:

determining a difference between the rate of change of the state of charge of the first cell and the rate of change of the state of charge of the second cell.

4. The method of claim 3, wherein comparing the rate of change of the state of charge of the battery against a threshold includes comparing the difference between the rate of change of the state of charge of the first cell and the rate of change of the state of charge of the second cell with the threshold.

5. The method of claim 1, wherein the method further comprises:

determining whether the battery is relaxed; and

determining the state of charge of the battery, wherein the state of charge of the battery is used to determine the rate of change of the state of charge of the battery.

6. The method of claim 5, wherein the battery is a multi-cell battery, wherein the multi-cell battery includes at least a first cell and a second cell, wherein determining the state of charge of the battery includes determining the state of charge of the first cell and determining the state of charge of the second cell, and wherein the method further comprises:

normalizing the state of charge of the first cell to a known state; and

normalizing the state of charge of the second cell to the known state.

7. The method of claim 6, wherein determining the rate of change of the state of charge of the battery includes determining the rate of change of the state of charge of the first cell using the normalized state of charge of the first cell, and determining the rate of change of the state of charge of the second cell using the normalized state of charge of the second cell, and wherein the method further comprises:

determining a difference between the rate of change of the state of charge of the first cell and the rate of change of the state of charge of the second cell; and

wherein comparing the rate of change of the state of charge of the battery against a threshold includes comparing the difference between the rate of change of the state of charge of the first cell and the rate of change of the state of charge of the second cell with the threshold.

8. The method of claim 1, wherein determining the rate of change of the state of charge of the battery is done by correlating measured voltage with state-of-charge using a pre-defined correlation function.

9. A battery system including predictive failure determination capability based on rate of change of state of charge, wherein the battery system comprises:

a battery;

a processor; and

a computer readable medium, wherein the computer readable medium includes instructions executable by the processor to;

determine a rate of change of the state of charge of the battery;

compare the rate of change of the state of charge of the battery against a threshold; and

indicate a potential failure where the result of the comparison is beyond the threshold.

10. The battery system of claim 9, wherein the battery is a single cell battery.

11. The battery system of claim 10, wherein the computer readable medium further includes instructions executable by the processor to adjust the rate of change of the state of charge of the battery to compensate for external current.

12. The battery system of claim 9, wherein the battery is a multi-cell battery, and wherein the multi-cell battery includes at least a first cell and a second cell.

13. The battery system of claim 12, wherein determining the rate of change of the state of charge of the battery includes determining the rate of change of the state of charge of the first cell and determining the rate of change of the state of charge of the second cell, and wherein the computer readable medium further includes instructions executable by the processor to:

determine a difference between the rate of change of the state of charge of the first cell and the rate of change of the state of charge of the second cell.

14. The battery system of claim 13, wherein comparing the rate of change of the state of charge of the battery against a threshold includes comparing the difference between the rate of change of the state of charge of the first cell and the rate of change of the state of charge of the second cell with the threshold.

15. The battery system of claim 9, wherein the computer readable medium further includes instructions executable by the processor to:

determine whether the battery is relaxed; and

determine the state of charge of the battery, wherein the state of charge of the battery is used to determine the rate of change of the state of charge of the battery.

16. The battery system of claim 15, wherein the battery is a multi-cell battery, wherein the multi-cell battery includes at least a first cell and a second cell, and wherein determining the state of charge of the battery includes determining the state of charge of the first cell and determining the state of charge of the second cell.

17. The battery system of claim 16, wherein the computer readable medium further includes instructions executable by the processor to:

normalize the state of charge of the first cell to a known state; and

normalize the state of charge of the second cell to the known state.

18. The battery system of claim 17, wherein determining the rate of change of the state of charge of the battery includes determining the rate of change of the state of charge of the first cell using the normalized state of charge of the first cell, and determining the rate of change of the state of charge of the second cell using the normalized state of charge of the second cell.

19. The battery system of claim 18, wherein the computer readable medium further includes instructions executable by the processor to:

determine a difference between the rate of change of the state of charge of the first cell and the rate of change of the state of charge of the second cell.

20. The battery system of claim 19, wherein comparing the rate of change of the state of charge of the battery against a threshold includes comparing the difference between the rate of change of the state of charge of the first cell and the rate of change of the state of charge of the second cell with the threshold.

21. An electronic system, wherein the electronic system comprises:

a battery powered electronic circuit, wherein the battery powered electronic circuit includes a device processor; and

a battery system, wherein the battery system powers the electronic circuitry, and wherein the battery system includes;

a battery;

a processor; and

a computer readable medium, wherein the computer readable medium includes instructions executable by the processor to;

determine a rate of change of the state of charge of the battery;

compare the rate of change of the state of charge of the battery against a threshold; and

indicate a potential failure where the result of the comparison is beyond the threshold.