MEASUREMENT DEVICE FOR MEASURING VOLTAGES ALONG A LINEAR ARRAY OF VOLTAGE SOURCES

• US 20130029245A1
• Filed: 07/24/2012
• Published: 01/31/2013
• Est. Priority Date: 07/25/2011
• Status: Active Grant

• Current Assignee: Bloom Energy Corporation
• Original Assignee: Bloom Energy Corporation
• Inventors: Russell, Ian, Pearson, Chad, Hintz, Robert, Edmonston, David, Couse, Stephen, Fisher, John Matthew, Erlin, Nathan Ben, Dubuk, Michael
• Granted Patent: US 8,993,191 B2
• Time in Patent Office: Days
• US Class Current: 429/467
• CPC Class Codes: G01R 1/06705 Apparatus for holding or moving single probes for moving multiple probe heads or ICs under test G01R31/2886
• CPC Class Codes: G01R 1/07 Non contact-making probes
• CPC Class Codes: G01R 19/0084 measuring voltage only all subgroups of G01R19/00 take precedence
• CPC Class Codes: G01R 31/36 Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: G01R 31/385 Arrangements for measuring battery or accumulator variables for monitoring G01R31/382
• CPC Class Codes: G01R 31/386 using test-loads
• 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
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 8/04537 Electric variables
• CPC Class Codes: H01M 8/04544 Voltage
• CPC Class Codes: H01M 8/04552 of the individual fuel cell
• CPC Class Codes: H01M 8/04559 of fuel cell stacks
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A measurement device for measuring voltages along a linear array of voltage sources, such as a fuel cell stack, includes at least one movable contact or non-contact voltage probe that measures a voltage of an array element.

Claims

1. A fuel cell system comprising:

at least one fuel cell stack; and

a measuring device comprising at least one movable contact or non-contact voltage probe that is configured to be propelled along the fuel cell stack to measure a voltage of fuel cell stack elements.

2. The fuel cell system of claim 1, wherein the at least one voltage probe is at least one contact probe.

3. The fuel cell system of claim 2, wherein the at least one contact probe has a resistivity sufficiently high to preclude electrically shorting adjacent fuel stack elements.

4. The fuel cell system of claim 3, wherein the resistivity of the at least one contact probe is in a range of 0.1 Ω

-cm to 3 Ω

-cm at 850°

C.

5. The fuel cell system of claim 2, wherein the at least one contact probe is configured to limit a shorting current to between 1 mA and 100 mA.

6. The fuel cell system of claim 2, wherein the at least one contact probe is constructed from a spinel ceramic material or a composite ceramic material.

7. The fuel cell system of claim 1, wherein the measuring device further comprises:

a movable carriage; and

one or more probe supports suspended from the movable carriage by swing arms, wherein the at least one probe is supported by the one or more probe supports and wherein the swings arms allow the one or more probe supports to swing freely below the movable carriage.

a screw mechanism for imparting linear motion to the carriage in a vertical direction;

one or more guide rails and wherein the guide rails guide the movable carriage parallel to the fuel cell stack;

a base and one or more supporting spines, wherein the one or more guide rails and the one or more spines are attached to the base;

an electrical conductor or conductive chain connected to the at least one probe for receiving a signal from the fuel cell stack; and

a signal processor configured to receive the signal from the electrical conductor and to determine a voltage from the signal.

8. The fuel cell system of claim 1, wherein the measuring device comprises two or more voltage probes aligned horizontally to measure a differential voltage between two or more portions of one fuel stack element.

9. The fuel cell system of claim 1, wherein the measuring device comprises two or more voltage probes offset horizontally and vertically to measure a differential voltage between two or more adjacent fuel stack elements that are offset vertically from each other.

10. The fuel cell system of claim 1, wherein the fuel cell stack elements comprise fuel cell interconnects.

11. The fuel cell system of claim 1, wherein the at least one voltage probe is a non-contact probe.

12. The fuel cell system of claim 11, wherein the measuring device further comprises:

a movable carriage; and

one or more probe supports suspended from the movable carriage, wherein the at least one non-contact probe is supported by the one or more probe supports and wherein a fixed displacement between the at least one non-contact probe and the fuel cell stack is maintained by an offset spacer supported by the one more probe supports, wherein the offset spacer is configured to contact the fuel cell stack, and

wherein the at least one non-contact probe comprises an electronically sensitive semiconductor junction configured to measure at least one of a cyclic electromagnetic field radiated by the fuel cell stack and a sinusoidal electromagnetic field superimposed on the fuel cell stack and radiated by the fuel cell stack.

13. A method of testing a fuel cell stack, comprising:

moving at least one contact or non-contact voltage probe along the fuel cell stack; and

sequentially measuring a voltage of fuel cell stack elements.

14. The method of claim 13, wherein the at least one voltage probe is at least one contact probe.

15. The method of claim 14, wherein the at least one contact probe has a resistivity sufficiently high to preclude shorting adjacent fuel stack elements.

16. The method of claim 15, wherein the resistivity of the at least one contact probe is in a range of 0.1 Ω

-cm to 3 Ω

-cm at 850°

C.

17. The method of claim 14, wherein the at least one contact probe is configured to limit a shorting current to between 1 mA and 100 mA when the probe simultaneously contacts two or more fuel cell stack elements.

18. The method of claim 14, wherein the at least one contact probe is constructed from a spinel ceramic material.

19. The method of claim 13, wherein the voltage of fuel cell stack elements is measured relative to a common reference.

20. The method of claim 14, wherein moving at least one contact or non-contact voltage probe along the fuel cell stack comprises actuating a screw mechanism to impart a vertical linear motion to a carriage to vertically move the carriage along at least one guide rail parallel to the fuel cell stack, such that at least one probe supported by at least one probe support from the carriage by at least one swing arm freely swings below the carriage to contact the fuel cell stack elements.

21. The method of claim 13, wherein the measuring device comprises two contact or non-contact voltage probes and wherein measuring a voltage of the fuel cell stack elements comprises:

measuring a first voltage of a first location on a stack element with a first probe;

measuring a second voltage of a second location on the fuel cell stack element with a second probe horizontally offset from the first probe, wherein the first and second voltage measurements are taken simultaneously; and

determining a differential voltage between the first and the second locations.

22. The method of claim 13, wherein the measuring device comprises two contact or non-contact voltage probes and wherein measuring a voltage of the fuel cell stack elements comprises:

measuring a first voltage of a first fuel stack element with a first probe;

measuring a second voltage of a second fuel cell stack element with a second probe vertically offset from the first probe, wherein the second fuel cell stack element is offset vertically from, and is located adjacent to, the first fuel cell stack element and wherein the first and second voltage measurements are taken simultaneously; and

determining a differential voltage between the first and the second fuel stack elements.

23. The method of claim 13, wherein the fuel cell stack elements comprise fuel cell interconnects, and further comprising determining an acceptability of a fuel cell located between first and second interconnects in the stack based on sequentially measuring the voltage of the first and the second interconnects.

24. The method of claim 13, wherein the at least one voltage probe is a non-contact probe.

25. The method of claim 24, wherein moving the at least one non-contact voltage probe along the fuel cell stack comprises moving the at least one non-contact voltage probe along the fuel cell stack at a fixed displacement, and wherein the at least one non-contact probe comprises an electronically sensitive semiconductor junction configured to measure at least one of a cyclic electromagnetic field radiated by the fuel cell stack and a sinusoidal electromagnetic field superimposed on the fuel cell stack and radiated by the fuel cell stack.

26. A measurement device for measuring a voltage of a linear array of voltage sources comprising:

a carriage;

one or more probes attached to the carriage, wherein each of the one or more probes comprises a sensing element configured to receive a signal from the linear array indicative of a voltage;

guide rails, wherein the guide rails guide the carriage parallel to the linear array;

a screw mechanism for imparting linear motion to the carriage;

an electrical conductor connected to each of the one or more probes for receiving the signal from the sensing element; and

a signal processor configured to receive the signal from the electrical conductor and to determine a voltage from the signal.

27. The measurement device of claim 26, wherein the linear array is an array of direct current sources selected from the group consisting of fuel cell stack elements, batteries, capacitors, photo-cells, and photovoltaic devices.

28. The measurement device of claim 26, wherein at least one of the one or more probes is a contact probe, wherein the sensing element of the contact probe is a conductor, and wherein the contact probe is in contact with the linear array.

29. The measurement device of claim 26, further comprising an offset spacer, wherein at least one of the one or more probes is a non-contact probe, wherein the offset spacer maintains the sensing element of the at least one non-contact probe at a pre-set distance from the linear array, and wherein the sensing element comprises a semiconductor PN junction.