Method and apparatus for testing cells and batteries embedded in series/parallel systems

• US 20020047711A1
• Filed: 05/21/2001
• Published: 04/25/2002
• Est. Priority Date: 09/14/2000
• Status: Abandoned Application

• Current Assignee: Midtronics Incorporated
• Original Assignee: Midtronics Incorporated
• Inventors: Bertness, Kevin I., Champlin, Keith S.
• Application Number:
  US09/862,783
• Publication Number:
  US 20020047711A1
• Time in Patent Office: Days
• US Class Current: 324/426
• CPC Class Codes: G01R 31/385 Arrangements for measuring battery or accumulator variables for monitoring G01R31/382
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery

Abstract

A “three-point” measurement technique precisely determines dynamic electrical parameters of individual cells/batteries and/or interconnecting conductors embedded in a larger series, parallel, or series-parallel battery/electrical system. Three measuring points are defined. Two of these points comprise terminals of the subject cell/battery or interconnecting conductor. The third measuring point is an adjacent point that is separated from one of the other two measuring points by a single conducting path that may include one or more cells or batteries. By measuring dynamic parameters between alternate pairs of these three measuring points, three dynamic parameter measurements are acquired. A mathematical computation combines the three measurements and uniquely determines the desired dynamic parameters of one or two subject elements—thus effectively “de-embedding” the subject elements from the remainder of the system. A “four-point” extension of this technique permits measuring individual dynamic parameters of single cells/batteries disposed internally in a multiple-unit string of parallel-connected cells/batteries.

Claims

1. Apparatus for evaluating a dynamic parameter of a particular element embedded in a system of interconnected electrochemical cells or batteries comprising:

dynamic parameter measuring circuitry adapted to contact first and second electrical contact points of said particular element and adapted to measure a first dynamic parameter between said first and second electrical contact points;

dynamic parameter measuring circuitry adapted to contact both said second electrical contact point and a third electrical contact point disposed on a conducting electrical path proceeding from said second electrical contact point and adapted to measure a second dynamic parameter between said second and third electrical contact points;

dynamic parameter measuring circuitry adapted to contact both said third electrical contact point and said first electrical contact point and adapted to measure a third dynamic parameter between said third and first electrical contact points;

computation circuitry adapted to compute said dynamic parameter of said particular element from measured values of said first, second, and third dynamic parameters.

2. Apparatus as in claim 1 wherein said dynamic parameter measuring circuitry contacts said first, second, and third electrical contact points with Kelvin contacts.

3. Apparatus as in claim 1 wherein said dynamic parameter is complex impedance.

4. Apparatus as in claim 1 wherein said dynamic parameter is complex admittance.

5. Apparatus as in claim 1 wherein said dynamic parameter is dynamic resistance.

6. Apparatus as in claim 1 wherein said dynamic parameter is dynamic conductance.

7. Apparatus as in claim 1 wherein said particular element is an electrochemical cell.

8. Apparatus as in claim 1 wherein said particular element is an electrochemical battery.

9. Apparatus as in claim 1 where said particular element is an interconnecting electrical conductor.

10. A method for evaluating a dynamic parameter of a particular element embedded in a system of interconnected electrochemical cells or batteries comprising:

measuring a first dynamic parameter between a first electrical contact point and a second electrical contact point of said particular element;

measuring a second dynamic parameter between said second electrical contact point and a third electrical contact point disposed on a conducting electrical path proceeding from said second electrical contact point;

measuring a third dynamic parameter between said third electrical contact point and said first electrical contact point; and

computing said dynamic parameter of said particular element from measured values of said first, second, and third dynamic parameters.

11. A method as in claim 10 wherein said dynamic parameter is complex impedance.

12. A method as in claim 10 wherein said dynamic parameter is complex admittance.

13. A method as in claim 10 wherein said dynamic parameter is dynamic resistance.

14. A method as in claim 10 wherein said dynamic parameter is dynamic conductance.

15. A method as in claim 10 wherein said particular element is an electrochemical cell.

16. A method as in claim 10 wherein said particular element is an electrochemical battery.

17. A method as in claim 10 wherein said particular element is an interconnecting electrical conductor.

18. A method as in claim 10 wherein said first, second, and third electrical contact points are contacted with Kelvin contacts.

20. A method as in claim 19 wherein said dynamic parameter is complex impedance.

21. A method as in claim 19 wherein said dynamic parameter is complex admittance.

22. A method as in claim 19 wherein said dynamic parameter is dynamic resistance.

23. A method as in claim 19 wherein said dynamic parameter is dynamic conductance.

24. A method as in claim 19 wherein said first, second, third, an fourth electrical contact points are contacted with Kelvin contacts.

26. A method as in claim 25 wherein said dynamic parameter is complex impedance.

27. A method as in claim 25 wherein said dynamic parameter is complex admittance.

28. A method as in claim 25 wherein said dynamic parameter is dynamic resistance.

29. A method as in claim 25 wherein said dynamic parameter is dynamic conductance.

30. A method as in claim 25 wherein said first, second, and third electrical contact points are contacted with Kelvin contacts.

47. Apparatus for evaluating a dynamic parameter of a particular element embedded in a system of interconnected electrochemical cells or batteries adapted for performing the steps according to claim 10.

48. Apparatus for evaluating a dynamic parameter of a particular cell or battery embedded internally in an array of parallel-connected electrochemical cells or batteries adapted for performing the steps according to claim 19.

49. Apparatus for evaluating a dynamic parameter of a particular interconnecting conductor embedded internally in an array of parallel-connected electrochemical cells or batteries adapted for performing the steps according to claim 25.

19. A method for evaluating a dynamic parameter of a particular cell or battery embedded internally in an array of parallel-connected electrochemical cells or batteries comprising:

measuring a first dynamic parameter between first and second electrical contact points comprising terminals of said particular cell or battery;

measuring a second dynamic parameter between said second electrical contact point and a third electrical contact point disposed on a first conducting electrical path proceeding from said second electrical contact point;

measuring a third dynamic parameter between said second electrical contact point and a fourth electrical contact point disposed on a second conducting electrical path proceeding from said second electrical contact point;

measuring a fourth dynamic parameter between said third electrical contact point and said first electrical contact point;

measuring a fifth dynamic parameter between said fourth electrical contact point and said first electrical contact point; and

computing said dynamic parameter of said particular cell or battery from measured values of said first, second, third, fourth, and fifth dynamic parameters.

25. A method for evaluating a dynamic parameter of a particular interconnecting conductor embedded internally in an array of parallel-connected electrochemical cells or batteries comprising:

measuring a first dynamic parameter between first and second electrical contact points of said particular interconnecting conductor, said second electrical contact point comprising one terminal of a particular cell or battery of said array;

measuring a second dynamic parameter between said second electrical contact point and a third electrical contact point comprising a second terminal of said cell or battery;

measuring a third dynamic parameter between said third electrical contact point and said first electrical contact point; and

computing said dynamic parameter of said particular interconnecting conductor from measured values of said first, second, and third dynamic parameters.

31. Apparatus for evaluating dynamic parameters of first and second adjacent electrical elements having a common connecting point and embedded in a system of interconnected electrochemical cells or batteries comprising:

dynamic parameter measuring circuitry adapted to contact said first adjacent electrical element at both a first electrical contact point and at said common connecting point, and adapted to measure a first dynamic parameter between said first electrical contact point and said common connecting point;

dynamic parameter measuring circuitry adapted to contact said second adjacent electrical element at both a second electrical contact point and at said common connecting point, and adapted to measure a second dynamic parameter between said second electrical contact point and said common connecting point;

dynamic parameter measuring circuitry adapted to contact both said second electrical contact point and said first electrical contact point and adapted to measure a third dynamic parameter between said second electrical contact point and said first electrical contact point;

computation circuitry adapted to compute said dynamic parameters of said first and second adjacent electrical elements from measured values of said first, second, and third dynamic parameters.

32. Apparatus as in claim 31 wherein said dynamic parameter measuring circuitry contacts said first and second electrical contact points and said common connecting point with Kelvin contacts.

33. Apparatus as in claim 31 wherein said dynamic parameter is complex impedance.

34. Apparatus as in claim 31 wherein said dynamic parameter is complex admittance.

35. Apparatus as in claim 31 wherein said dynamic parameter is dynamic resistance.

36. Apparatus as in claim 31 wherein said dynamic parameter is dynamic conductance.

37. Apparatus as in claim 31 wherein said first and second adjacent electrical elements comprise an electrochemical cell and an interconnecting electrical conductor.

38. Apparatus as in claim 31 wherein said first and second adjacent electrical elements comprise an electrochemical battery and an interconnecting electrical conductor.

40. A method as in claim 39 wherein said first, second, and third dynamic parameters are measured with Kelvin contacts.

41. A method as in claim 39 wherein said dynamic parameter is complex impedance.

42. A method as in claim 39 wherein said dynamic parameter is complex admittance.

43. A method as in claim 39 wherein said dynamic parameter is dynamic resistance.

44. A method as in claim 39 wherein said dynamic parameter is dynamic conductance.

45. A method as in claim 39 wherein said first and second adjacent electrical elements comprise an electrochemical cell and an interconnecting electrical conductor.

46. A method as in claim 39 wherein said first and second adjacent electrical elements comprise an electrochemical battery and an interconnecting electrical conductor.

50. Apparatus for evaluating dynamic parameters of first and second adjacent electrical elements having a common connecting point and embedded in a system of interconnected electrochemical cells or batteries adapted for performing the steps according to claim 39.

39. A method for evaluating dynamic parameters of first and second adjacent electrical elements having a common connecting point and embedded in a system of interconnected electrochemical cells or batteries comprising:

measuring a first dynamic parameter between said common connecting point and a first electrical contact point on said first adjacent electrical element;

measuring a second dynamic parameter between said common connecting point and a second electrical contact point on said second adjacent electrical element;

measuring a third dynamic parameter between said first electrical contact point and said second electrical contact point; and

computing said dynamic parameters of said first and second adjacent electrical elements from said first dynamic parameter, said second dynamic parameter, and said third dynamic parameter.

51. Apparatus for de-embedding dynamic parameters of electrical elements embedded in a system of electrochemical cells/batteries and conductors interconnected at m interconnection points comprising:

dynamic parameter measuring circuitry adapted to measure a dynamic parameter of an isolated element connected between its input conductors;

system-contacting conductors adapted to make electrical contacts to elements of said system at n interconnection points where n is an integer greater than two and less than m+1;

switching circuitry interposed between said system-contacting conductors and said input conductors and adapted to connect pairs of said system-contacting conductors to said input conductors;

control circuitry adapted to command said switching circuitry to selectively connect particular pairs of said system-contacting conductors to said input conductors and to command said dynamic parameter measuring circuitry to determine a measured dynamic parameter value with a said particular pair of said system-contacting conductors connected to said input conductors;

memory circuitry adapted to store each of said measured dynamic parameter values; and

computation circuitry adapted to compute one or more de-embedded dynamic parameters from said measured dynamic parameter values stored in said memory circuitry.

52. Apparatus as in claim 51 wherein n is equal to three.

53. Apparatus as in claim 51 wherein n is equal to four.

54. Apparatus as in claim 51 wherein n is equal to M.

55. Apparatus as in claim 51 wherein said input conductors are Kelvin input conductors, said system-contacting conductors are Kelvin system-contacting conductors, and said electrical contacts are Kelvin electrical contacts.

56. Apparatus as in claim 51 wherein said dynamic parameter is complex impedance.

57. Apparatus as in claim 51 wherein said dynamic parameter is complex admittance.

58. Apparatus as in claim 51 wherein said dynamic parameter is dynamic resistance.

59. Apparatus as in claim 51 wherein said dynamic parameter is dynamic conductance.

60. Apparatus as in claim 51 wherein said electrical elements are electrochemical cells.

61. Apparatus as in claim 51 wherein said electrical elements are electrochemical batteries.

62. Apparatus as in claim 51 wherein said electrical elements are electrical conductors.

63. Apparatus as in claim 51 wherein said computation circuitry computes a said de-embedded dynamic parameter from three said measured dynamic parameter values.

64. Apparatus as in claim 51 wherein said computation circuitry computes a said de-embedded dynamic parameter from five said measured dynamic parameter values.

65. Apparatus as in claim 51 wherein said control circuitry and said computation circuitry comprise a microprocessor or microcontroller.