Battery charge indication methods, battery charge monitoring devices, rechargeable batteries, and articles of manufacture

• US 7,808,210 B2
• Filed: 11/24/2009
• Issued: 10/05/2010
• Est. Priority Date: 03/31/2006
• Status: Active Grant

• Current Assignee: Lithion Battery Incorporated
• Original Assignee: Valence Technology Incorporated (Lithium Werks B.V.)
• Inventors: Darilek, Christopher
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): DIAO, M BAYE
• Application Number:
  US12/625,326
• Publication Number:
  US 20100070220A1
• Time in Patent Office: 315 Days
• Field of Search: 320/132, 702/63
• US Class Current: 320/132
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Battery charge indication methods, battery state of charge monitoring devices, rechargeable batteries, and articles of manufacture are described. According to one aspect, a battery charge indication method includes first determining a state of charge of a battery at a first moment in time using a first method, second determining a state of charge of the battery at a second moment in time using a second method different than the first method, and providing information regarding the state of charge of the battery at the first and second moments in time using information of the first and second determinings.

Claims

1. A method for determining a reported state of charge of a battery system, the method comprising:

determining the reported state of charge according to a first method when a previous state of charge is greater than a first threshold percentage and less than or equal to 100%;

determining the reported state of charge according to a second method when the previous state of charge is greater than a second threshold percentage and less than or equal to the first threshold percentage;

determining the reported state of charge according to a third method when the previous state of charge is greater than or equal to 0% and less than or equal to the second threshold percentage.

2. The method of claim 1 wherein:

determining the reported state of charge according to the first method comprises monitoring a monitored current of the battery system; and

determining the reported state of charge according to the third method comprises monitoring a voltage of a cell of the battery system.

3. The method of claim 2 wherein determining the reported state of charge according to the second method comprises combining information of the first and third methods.

4. The method of claim 3 wherein determining the reported state of charge according to the first method further comprises counting coulombs of the monitored current of the battery system.

5. The method of claim 3 wherein determining the reported state of charge according to the first method further comprises determining an estimated state of charge based on an estimated capacity of the battery system and the counted coulombs of the monitored current of the battery system.

6. The method of claim 3 wherein determining the reported state of charge according to the third method further comprises determining an estimated state of charge using at least one predetermined discharge voltage model.

7. The method of claim 6, wherein:

the at least one predetermined discharge voltage model is selected from a plurality of possible discharge voltage model according to a current and a temperature of the cell; and

the estimated state of charge is determined to be the state of charge of the at least one discharge voltage model according to a measured voltage of the cell.

8. The method of claim 1, further comprising calculating a learned capacity of the battery system using the reported state of charge of the battery system and a coulomb discharge value.

9. The method of claim 1, further comprising determining the reported state of charge according to the first method when a charge current is present in the battery system.

10. An apparatus for determining a reported state of charge of a battery system, the apparatus comprising a computer processor and a computer memory operatively coupled to the computer processor, the computer memory having disposed within it computer instructions capable of:

determining the reported state of charge according to a first method when a previous state of charge is greater than a first threshold percentage and less than or equal to 100%;

determining the reported state of charge according to a second method when the previous state of charge is greater than a second threshold percentage and less than or equal to the first threshold percentage;

determining the reported state of charge according to a third method when the previous state of charge is greater than or equal to 0% and less than or equal to the second threshold percentage.

11. The apparatus of claim 10 wherein:

determining the reported state of charge according to the first method comprises monitoring a monitored current of the battery system; and

determining the reported state of charge according to the third method comprises monitoring a voltage of a cell of the battery system.

12. The apparatus of claim 11 wherein determining the reported state of charge according to the second method comprises combining information of the first and third methods.

13. The apparatus of claim 12 wherein determining the reported state of charge according to the first method further comprises counting coulombs of the monitored current of the battery system.

14. The apparatus of claim 12 wherein determining the reported state of charge according to the first method further comprises determining an estimated state of charge based on an estimated capacity of the battery system and the counted coulombs of the monitored current of the battery system.

15. The apparatus of claim 12 wherein determining the reported state of charge according to the third method further comprises determining an estimated state of charge using at least one predetermined discharge voltage model.

16. The apparatus of claim 15, wherein:

the at least one predetermined discharge voltage model is selected from a plurality of possible discharge voltage model according to a current and a temperature of the cell; and

the estimated state of charge is determined to be the state of charge of the at least one discharge voltage model according to a measured voltage of the cell.

17. The apparatus of claim 10 wherein the computer memory further includes computer instructions capable of calculating a learned capacity of the battery system using the reported state of charge of the battery system and a coulomb discharge value.

18. The apparatus of claim 10 wherein the computer memory further includes computer instructions capable of determining the reported state of charge according to the first method when a charge current is present in the battery system.

19. A computer program product embodied on a tangible computer-readable medium for determining a reported state of charge of a battery system, the computer program product comprising:

computer program instructions for determining the reported state of charge according to a first method when a previous state of charge is greater than a first threshold percentage and less than or equal to 100%;

computer program instructions for determining the reported state of charge according to a second method when the previous state of charge is greater than a second threshold percentage and less than or equal to the first threshold percentage;

computer program instructions for determining the reported state of charge according to a third method when the previous state of charge is greater than or equal to 0% and less than or equal to the second threshold percentage.

20. The computer program product of claim 19 wherein:

determining the reported state of charge according to the first method comprises monitoring a monitored current of the battery system; and

determining the reported state of charge according to the third method comprises monitoring a voltage of a cell of the battery system.

21. The computer program product of claim 20 wherein determining the reported state of charge according to the second method comprises combining information of the first and third methods.

22. The computer program product of claim 21 wherein determining the reported state of charge according to the first method further comprises counting coulombs of the monitored current of the battery system.

23. The computer program product of claim 21 wherein determining the reported state of charge according to the first method further comprises determining an estimated state of charge based on an estimated capacity of the battery system and the counted coulombs of the monitored current of the battery system.

24. The computer program product of claim 21 wherein determining the reported state of charge according to the third method further comprises determining an estimated state of charge using at least one predetermined discharge voltage model.

25. The computer program product of claim 24, wherein:

the at least one predetermined discharge voltage model is selected from a plurality of possible discharge voltage model according to a current and a temperature of the cell; and

the estimated state of charge is determined to be the state of charge of the at least one discharge voltage model according to a measured voltage of the cell.

26. The computer program product of claim 19, further comprising computer program instructions for calculating a learned capacity of the battery system using the reported state of charge of the battery system and a coulomb discharge value.

27. The computer program product of claim 19, further comprising computer program instructions for determining the reported state of charge according to the first method when a charge current is present in the battery system.