Crack detection in ceramics using electrical conductors
View Patent ↗Various embodiments provide methods and systems for detecting cracks in ceramic electrolytes using electrical conductors. A method for testing an electrolyte material, such as a ceramic electrolyte material for use in a solid oxide fuel cell device, includes providing a conductive path on the electrolyte material, electrically connecting a probe across the conductive path, and measuring a value associated with the conductive path to determine the presence or absence of a crack in the material.
1. A method for testing an electrolyte material, comprising:
providing an electrolyte material and a conductive path directly contacting the electrolyte material, the conductive path comprising at least one of a conductive trace and a wire;
electrically connecting a probe across the conductive path; and
measuring a value associated with the conductive path to determine the presence or absence of a crack in the electrolyte material,
wherein the electrolyte material comprises an electrolyte for a solid oxide fuel cell; and
wherein the conductive path is located on a cathode-side surface of the electrolyte material and at least partially surrounds a fuel riser opening extending though the electrolyte material.
2. The method of claim 1 , wherein the value comprises a resistance of the path.
3. The method of claim 1 , wherein the value comprises a current in the path.
4. The method of claim 1 , further comprising:
comparing the value with an expected or baseline value; and
determining the presence of a crack based on a difference between the measured value and the expected or baseline value.
5. The method of claim 1 , wherein providing the conductive path comprises providing the conductive trace on the electrolyte material using a thin-film or thick-film processing technique.
6. The method of claim 1 , wherein:
the conductive path has a width of between about 5 and 10 microns; and
the conductive path has a height or thickness that is less than about 1 micron.
7. The method of claim 1 , wherein providing the conductive path comprises providing the wire.
8. The method of claim 1 , further comprising: at least one contact area on the electrolyte material for connecting a probe across the conductive trace.
9. The method of claim 1 , wherein the conductive path is provided proximate to an opening or hole in the electrolyte material.
10. The method of claim 1 , wherein the conductive path is provided proximate to an edge or corner of the electrolyte material.
11. The method of claim 1 , further comprising providing a plurality of conductive paths on the electrolyte material.
12. The method of claim 1 , wherein the electrolyte material comprises a ceramic material.
13. The method of claim 1 , wherein the step of measuring the value is conducted at an operating temperature of the solid oxide fuel cell stack.
14. The method of claim 13 , wherein the step of measuring the value is conducted while the electrolyte material is disposed in a fuel cell on a stack located in a hot box and while the stack is operating to generate electricity, the fuel cell stack comprising fuel cells and interconnects electrically connecting the fuel cells.
15. The method of claim 1 , wherein the step of measuring the value is conducted at room temperature of a partially or fully assembled fuel cell stack in a test station before the stack is placed into a hot box.
16. The method of claim 1 , wherein the conductive path comprises a noble metal trace.
17. The method of claim 1 , wherein the conductive path comprises a conductive oxide trace.
18. The method of claim 1 , wherein the probe comprises an ohmmeter.
19. A method for testing an electrolyte material, comprising:
providing an electrolyte material and a conductive path comprising a conductive trace directly contacting the electrolyte material;
electrically connecting a probe across the conductive path;
providing a current to the conductive path to burn out the conductive path; and
measuring a burnout characteristic of the conductive path to determine the presence or absence of a crack in the electrolyte material,
wherein the electrolyte material comprises an electrolyte for a solid oxide fuel cell; and
wherein the conductive path is located on a cathode-side surface of the electrolyte material and at least partially surrounds a fuel riser opening extending though the electrolyte material.
20. An apparatus for testing an electrolyte material, comprising:
a support for holding an electrolyte material having a conductive path comprising at least one of a conductive trace and a wire directly contacting the electrolyte material;
a probe for making an electrical connection across the conductive path; and
a measurement device coupled to the probe that measures an electrical characteristic of the conductive path to detect the presence or absence of a crack in the electrolyte material,
wherein the electrolyte material comprises an electrolyte for a solid oxide fuel cell; and
wherein the conductive path is located on a cathode-side surface of the electrolyte material and at least partially surrounds a fuel riser opening extending though the electrolyte material.