Thermoelectric generator
Disclosed are apparatus and methodology for constructing thermoelectric devices (TEDs). N-type elements are paired with P-type elements in an array of pairs between substrates. The paired elements are electrically connected in series by various techniques including brazing for hot side and/or also cold side connections, and soldering for cold side connections while being thermally connected in parallel. In selected embodiments, electrical and mechanical connections of the elements may be made solely by mechanical pressure.
1. A thermoelectric device for converting thermal energy to electrical energy based on temperature differences between portions of the device, comprising:
a plurality of N-type oxide ceramic elements comprising an N-type ceramic material;
a plurality of P-type oxide ceramic elements comprising a P-type ceramic material and respectively paired with said plurality of N-type elements;
a pair of supporting generally planar ceramic substrates, supporting a plurality of conductive traces thereon, and with said paired N-type and P-type elements received on selected of said conductive traces so as to form an array of such pairs captured between said substrates;
insulating foam potting material captured between said substrates in between said array pairs; and
at least one pair of connection terminals provided on at least one of said substrates, and associated lead wires respectively connected thereto;
wherein said paired elements are electrically connected in series by said conductive traces and thermally connected in parallel relative to said substrates, so that generated electricity may be conducted from such array based on temperature differences between portions of said paired elements based on the Peltier/Seebeck effect, and wherein said plurality of N-type elements and said plurality of P-type elements comprise a plurality of porosity layers, the plurality of porosity layers being spaced apart in a heat-flow direction perpendicular to said generally planar ceramic substrates, the plurality of porosity layers having thicknesses in the heat-flow direction that range from 1 micron to 100 microns, and wherein the plurality of porosity layers comprise pores formed inside the N-type ceramic material and P-type ceramic material.
2. The thermoelectric device as in claim 1 , further including hermetic sealing material surrounding the peripheral edges of said potting material, for hermetically sealing said device.
3. The thermoelectric device as in claim 2 , wherein said hermetic sealing material comprises glass frit, and said substrates comprise alumina.
4. The thermoelectric device as in claim 1 , wherein said conductive traces comprise complementary patterns of screen-printed, fired metallizations formed on said substrates.
5. The thermoelectric device as in claim 1 , wherein:
said N-type elements comprise SrTiO 3 material incorporating doping material comprising at least one of Nb and La; and
said P-type elements comprise NiO material incorporating doping material comprising at least Li.
6. The thermoelectric device as in claim 1 , wherein the thicknesses in the heat-flow direction of the plurality porosity layers range from 2 microns to 100 microns.
7. The thermoelectric device as in claim 1 , wherein the thicknesses in the heat-flow direction of the plurality porosity layers range from 10 microns to 100 microns.
8. The thermoelectric device as in claim 1 , wherein the thicknesses in the heat-flow direction of the plurality porosity layers range from 20 microns to 100 microns.
9. A thermoelectric generator module for converting thermal energy to electrical energy based on temperature differences between portions of the module based on the Peltier/Seebeck effect, comprising:
a plurality of N-type elements comprising an N-type ceramic material;
a plurality of P-type elements comprising a P-type ceramic material and respectively paired with said plurality of N-type elements;
a pair of supporting ceramic substrates, supporting a plurality of conductive traces thereon, and with said paired N-type and P-type elements received on said conductive traces so as to form an array of such pairs between said substrates, with said paired elements electrically connected in series by said conductive traces and thermally connected in parallel relative to said substrates; and
at least one pair of connection terminals provided on at least one of said substrates, for the connection of leads thereto;
wherein said plurality of N-type elements and said plurality of P-type elements comprise a plurality of porosity layers, the plurality of porosity layers being spaced apart in a heat-flow direction perpendicular to said generally planar ceramic substrates, the plurality of porosity layers having thicknesses in the heat-flow direction that range from 1 micron to 100 microns, and wherein the plurality of porosity layers comprise pores formed inside the N-type ceramic material and P-type ceramic material.
10. A thermoelectric generator module as in claim 9 , wherein said N-type elements and said P-type elements further comprise at least one of graded and lamellar metallic microstructures including at least one of added metallization on ends of said N-type elements and said P-type elements, bond assisting metallic components incorporated into said N-type elements and said P-type elements, internal tabs extending from an end surface of said N-type elements and said P-type elements, metallic particles proximate respective N-type element and said P-type element ends, and stacked layers of gradually reduced metal particle concentration in said N-type elements and said P-type elements.
11. The thermoelectric generator module as in claim 9 , wherein said pores range from about 1 to about 40 microns in diameter.
12. A thermoelectric generator module as in claim 9 , wherein said N-type elements and said P-type elements further comprise relatively heavily doped layers of ceramic material adjacent to surfaces of said N-type elements and said P-type elements.
13. The thermoelectric generator module as in claim 9 , wherein said substrates comprise planar constructions capturing said array of paired elements between said substrates.
14. The thermoelectric generator module as in claim 13 , wherein said conductive traces comprise screen-printed, fired paste materials on at least one of said substrates, wherein said paste materials comprise alloyed powders including at least one of copper, nickel, silver, palladium, platinum or gold.
15. The thermoelectric generator module as in claim 13 , wherein said conductive traces comprise complementary patterns of screen-printed, fired metallizations formed on said substrates.
16. A thermoelectric generator module as in claim 9 , further including:
bonding material adjacent ends of said N-type elements and said P-type elements, respectively; and
thick film composite terminations between said bonding material and said conductive traces, respectively.
17. A thermoelectric generator module as in claim 16 , wherein said thick film composite terminations comprise ceramic/glass/metal composite structures.
18. The thermoelectric generator module as in claim 9 , wherein:
said N-type elements comprise SrTiO 3 material incorporating doping material comprising at least one of Nb and La; and
said P-type elements comprise NiO material incorporating doping material comprising at least Li material.
19. The thermoelectric generator module as in claim 9 , further including:
potting material captured between said substrates in between said array pairs; and
hermetic sealing material surrounding the peripheral edges of said potting material, for hermetically sealing said module.
20. The thermoelectric generator module as in claim 9 , wherein the thicknesses in the heat-flow direction of the plurality porosity layers range from 2 microns to 100 microns.
21. A thermoelectric generator module for converting thermal energy to electrical energy based on temperature differences between portions of the module based on the Peltier/Seebeck effect, comprising:
a plurality of N-type oxide ceramic elements comprising an N-type ceramic material;
a plurality of P-type oxide ceramic elements comprising a P-type ceramic material and respectively paired with said plurality of N-type elements;
a pair of supporting ceramic substrates, supporting a plurality of conductive traces thereon, and with said paired N-type and P-type elements received on said conductive traces so as to form an array of such pairs between said substrates, with said paired elements electrically connected in series by said conductive traces and thermally connected in parallel relative to said substrates; and
at least one pair of connection terminals provided on at least one of said substrates, for the connection of leads thereto;
wherein said plurality of N-type and P-type elements comprise structures of a tapered physical shape, and wherein said plurality of N-type elements and said plurality of P-type elements comprise a plurality of porosity layers, the plurality of porosity layers being spaced apart in a heat-flow direction perpendicular to said generally planar ceramic substrates, the plurality of porosity layers having thicknesses in the heat-flow direction that range from 1 micron to 100 microns, and wherein the plurality of porosity layers comprise pores formed inside the N-type ceramic material and P-type ceramic material.
22. The thermoelectric generator module as in claim 21 , wherein said substrates comprise planar constructions capturing said array of paired elements between said substrates.
23. The thermoelectric generator module as in claim 22 , wherein said conductive traces comprise screen-printed, fired paste materials on at least one of said substrates, wherein said paste materials comprise at least one of copper, nickel, silver, palladium, platinum, or gold pastes, or pastes comprising alloyed powders of such.
24. The thermoelectric generator module as in claim 22 , wherein said conductive traces comprise complementary patterns of screen-printed, fired metallizations formed on said substrates.
25. A thermoelectric generator module as in claim 21 , further including:
bonding material adjacent ends of said N-type elements and said P-type elements, respectively; and
thick film composite terminations between said bonding material and said conductive traces, respectively.
26. The thermoelectric generator module as in claim 21 , further including:
potting material captured between said substrates in between said array pairs; and
hermetic sealing material surrounding the peripheral edges of said potting material, for hermetically sealing said module.