Thermoelectric generator

Abstract

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.

What is claimed is: 
     
         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;   a plurality of P-type oxide ceramic elements, 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 selected of said conductive traces so as to form an array of such pairs between 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 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.   
     
     
         2 . A thermoelectric device as in  claim 1 , wherein said substrates comprise planar constructions forming a sandwich of said array of paired elements between said substrates. 
     
     
         3 . A thermoelectric device as in  claim 2 , wherein said conductive traces comprise screen-printed, fired thick paste materials on at least one of said substrates. 
     
     
         4 . A thermoelectric device as in  claim 2 , wherein said conductive traces comprise complementary patterns of screen-printed, fired metallizations formed on said substrates. 
     
     
         5 . A thermoelectric device as in  claim 2 , wherein:
 said N-type elements comprise SrTiO3 material incorporating doping material; and   said P-type elements comprise NiO material incorporating doping material.   
     
     
         6 . A thermoelectric device as in  claim 5 , wherein:
 said doping material for said N-type elements comprises at least one of Nb and La; and   said doping material for said P-type elements comprises at least Li material.   
     
     
         7 . A thermoelectric device as in  claim 1 , wherein said plurality of N-type and P-type elements comprise at least one of graded and lamellar structures which create non-uniform concentrations of at least one of porosity, metallization, and chemical composition of said elements, to provide selected thermal expansion and bonding properties of said elements. 
     
     
         8 . A thermoelectric device as in  claim 1 , wherein said plurality of N-type and P-type elements each respectively have dimensions in length, width, and height ranging from about 125 microns to at least 3 millimeters. 
     
     
         9 . A thermoelectric device as in  claim 1 , further including bonding material between said elements and said conductive traces, respectively. 
     
     
         10 . A thermoelectric device as in  claim 1 , wherein said substrates comprise ceramic rings forming concentric radial configurations having a generally open central portion adapted for exposure to a heat source with the exterior portion of the thermoelectric device adapted for exposure to an environment cooler than said heat source. 
     
     
         11 . A thermoelectric device as in  claim 10 , wherein said conductive traces include brazing for one of the ends of said paired elements. 
     
     
         12 . A thermoelectric device for converting thermal energy to electrical energy using electrically coupled doped semiconductive ceramic elements to generate electricity based on temperature differences between portions of the device, comprising:
 a plurality of N-type elements, each comprising a doped semiconductive oxide ceramic element;   a plurality of P-type elements, each comprising a doped semiconductive oxide ceramic element, respectively paired with said plurality of N-type elements;   a pair of supporting ceramic rings forming concentric radial configurations having a generally open central portion adapted for exposure to a heat source with the exterior portion of the thermoelectric device adapted for exposure to an environment cooler than said heat source, and with said paired N-type and P-type elements received on selected portions of said ceramic rings so as to form a radial array of such pairs; and   electrical connections for electrically connecting said paired elements in series while said paired elements are thermally connected in parallel relative to said ceramic rings, 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.   
     
     
         13 . A thermoelectric device as in  claim 12 , further including mechanical retention mechanism for holding said paired elements in mutual contact. 
     
     
         14 . A thermoelectric device as in  claim 13 , wherein said mechanical retention mechanism includes at least one matching bolt and nut. 
     
     
         15 . A thermoelectric device as in  claim 12 , wherein said electrical connections further include brazing for one of the ends of said paired elements and soldering for the other of the ends of said paired elements. 
     
     
         16 . Thermoelectric generator module for converting thermal energy to electrical energy using electrically coupled doped semiconductive ceramic elements to generate electricity based on temperature differences between portions of the module based on the Peltier/Seebeck effect, comprising:
 a plurality of N-type elements, each comprising a doped semiconductive oxide ceramic element;   a plurality of P-type elements, each comprising a doped semiconductive oxide ceramic element, respectively paired with said plurality of N-type elements;   an opposing pair of generally planar supporting ceramic substrates, supporting a plurality of complementary 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 sandwiched between 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 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 via said connection terminals based on temperature differences between portions of said paired elements.   
     
     
         17 . A thermoelectric generator module as in  claim 16 , wherein said conductive traces comprise complementary patterns of screen-printed, fired metallizations formed on said substrates. 
     
     
         18 . A thermoelectric generator module as in  claim 16 , wherein:
 said N-type elements comprise SrTiO3 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 . A thermoelectric generator module as in  claim 16 , wherein said plurality of N-type and P-type elements comprise at least one of graded and lamellar structures which create non-uniform concentrations of at least one of porosity, metallization, and chemical composition of said elements, to provide selected thermal expansion and bonding properties of said elements. 
     
     
         20 . A thermoelectric generator module as in  claim 16 , wherein said plurality of N-type and P-type elements each respectively have dimensions in length, width, and height ranging from about 125 microns to at least 3 millimeters. 
     
     
         21 . A thermoelectric generator module as in  claim 16 , further including bonding material between said elements and said conductive traces, respectively. 
     
     
         22 . Methodology for generating electrical energy based on the Peltier/Seebeck effect using oxide ceramic elements by providing a thermoelectric module constructed by coupling N-type and P-type materials as individual elements to form pairs electrically connected in series and thermally in parallel between opposing supporting substrates. 
     
     
         23 . Methodology as in  claim 22 , further including using one of thick and thin film manufacturing techniques to selectively produce metallizations serving as electrical interconnections for said individual elements capable of performing with relatively higher temperatures. 
     
     
         24 . Methodology as in  claim 22 , wherein said supporting substrates have screen-printed metallizations for electrically coupling said individual elements. 
     
     
         25 . Methodology as in  claim 22 , wherein said individual elements comprise p-type and n-type semiconducting materials prepared using standard ceramic engineering processing. 
     
     
         26 . Methodology as in  claim 25 , wherein:
 said n-type semiconducting material comprises an n-type semiconducting oxide ceramic composition constructed primarily of strontium titanate (SrTi03) with from 0 to 5 weight percent of added strontium oxide, niobium oxide, lanthanum oxide, bismuth oxide, silicon dioxide, aluminum oxide, sodium oxide, tantalum oxide, neodymium oxide, cerium oxide, molybdenum oxide, tungsten oxide and/or titanium dioxide; and   said p-type semiconducting material comprises a p-type semiconducting oxide ceramic composition constructed primarily of nickel oxide with from 0 to 8 weight percent of added lithium oxide, sodium oxide, potassium oxide and/or bismuth oxide.   
     
     
         27 . Methodology as in  claim 22 , wherein said individual elements comprise p-type and n-type semiconducting materials prepared using ceramic blanks from which said individual elements are cut, with said ceramic blank formed from green body formation techniques. 
     
     
         28 . Methodology as in  claim 27 , wherein said green body formation techniques comprise at least one of die-pressing, extrusion, tape casting, and wet laydown. 
     
     
         29 . Methodology as in  claim 27 , wherein said green body formation techniques include the use of at least one of graded and lamellar microstructures within said plurality of N-type and P-type individual elements so as to selectively create non-uniform concentrations of at least one of porosity, metallization, and chemical composition of said elements, to provide selected thermal expansion and bonding properties of said elements, to facilitate creation of modules adapted for operating with high temperatures in a range of from about 300 to 800 degrees C., and with temperature differentials (ΔT) of at least 100 degrees C. 
     
     
         30 . Methodology as in  claim 22 , further including providing an adhesion layer respectively between said individual elements and electrical connections thereof. 
     
     
         31 . Methodology as in  claim 22 , wherein said individual N-type and P-type elements each respectively have dimensions in length, width, and height ranging from about 125 microns to at least 3 millimeters. 
     
     
         32 . Methodology as in  claim 22 , wherein said supporting substrates comprise planar headers supporting selected arrangements of metallized portions thereon, and said methodology further includes aligning and placing said individual N-type and P-type elements in respective alternating positions directly inline with their metallized portions on said headers. 
     
     
         33 . Methodology as in  claim 32 , further including one of simultaneously and separately brazing both headers to said individual elements, with selected materials for specific temperature responsive performance. 
     
     
         34 . Methodology as in  claim 22 , further including providing bonding pads on at least one of said supporting substrates, electrically connected so to allow connection of the module to either an electrical load which will use the thermoelectric power generated or to other thermoelectric modules in series to increase the voltage or current and therefore the overall power generated. 
     
     
         35 . Methodology as in  claim 22 , wherein said supporting substrates form a concentric radial configuration wherein a central location of said radial configuration is intended for exposure to a heat source while radially outward portions of said configuration are intended for relatively lower temperature sources. 
     
     
         36 . Methodology as in  claim 35 , wherein one end of the pairs of N-type and P-type materials individual elements are directly brazed together while the other end of the pairs of said elements are soldered to a radially outward one of said substrates. 
     
     
         37 . Methodology for manufacturing a thermoelectric generator module for converting thermal energy to electrical energy using electrically coupled doped semiconductive oxide ceramic elements to generate electricity based on temperature differences between portions of the module based on the Peltier/Seebeck effect, comprising:
 providing an opposing pair of generally planar supporting ceramic substrates, supporting a plurality of complementary conductive traces thereon;   placing an array of plural paired N-type elements and P-type elements in electrical communication with said conductive traces so that the paired elements are electrically connected in series by said conductive traces, said elements each comprising a doped semiconductive oxide ceramic element, and such that said elements are thermally connected in parallel relative to said substrates; and   attaching at least one pair of connection terminals on at least one of said substrates, for the connection of leads thereto, so that generated electricity may be conducted from such array via said connection terminals based on temperature differences between portions of said paired elements.   
     
     
         38 . Methodology as in  claim 37 , said conductive traces are formed by patterns of screen-printed, fired metallizations formed on said substrates. 
     
     
         39 . Methodology as in  claim 37 , wherein:
 said N-type elements comprise SrTiO3 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.   
     
     
         40 . Methodology as in  claim 37 , further including selectively providing at least one of graded and lamellar structures within said plurality of N-type and P-type elements so as to selectively create non-uniform concentrations of at least one of porosity, metallization, and chemical composition of said elements, to provide selected thermal expansion and bonding properties of said elements. 
     
     
         41 . Methodology as in  claim 37 , wherein said plurality of N-type and P-type elements each respectively have dimensions in length, width, and height ranging from about 125 microns to at least 3 millimeters. 
     
     
         42 . Methodology as in  claim 37 , further including providing bonding material between said elements and said conductive traces, respectively. 
     
     
         43 . A method of providing a thermoelectric device for converting thermal energy to electrical energy based on temperature differences between portions of the device, comprising:
 forming respective pluralities of N-type and P-type oxide ceramic elements;   providing a pair of ceramic substrates with a plurality of predetermined conductive traces thereon;   respectively pairing and aligning said N-type and P-type elements on selected of said conductive traces so as to form an array of such pairs electrically connected in series and captured between said substrates and thermally connected in parallel between opposing determined hot and cold sides thereof; and   forming at least one pair of connection terminals on at least one of said substrates, for the connection of leads thereto, so that generated electricity may be conducted from such array based on temperature differences between such hot and cold sides based on the Peltier/Seebeck effect.   
     
     
         44 . A method as in  claim 43 , wherein said substrates comprise one of planar constructions forming a sandwich of said array of paired elements between said substrates, and ceramic rings forming concentric radial configurations having a generally open central portion adapted for exposure to a heat source with the exterior portion of the thermoelectric device adapted for exposure to an environment cooler than said heat source. 
     
     
         45 . A method as in  claim 43 , wherein said conductive traces are formed by screen-printed, fired metallizations on said substrates. 
     
     
         46 . A method as in  claim 43 , wherein:
 said N-type elements comprise SrTiO3 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.   
     
     
         47 . A method as in  claim 43 , wherein said plurality of N-type and P-type elements are formed of at least one of graded and lamellar structures which create non-uniform concentrations of at least one of porosity, metallization, and chemical composition of said elements, to provide selected thermal expansion and bonding properties of said elements. 
     
     
         48 . A method as in  claim 43 , further including:
 bonding material between said elements and said conductive traces, respectively; and   wherein said plurality of N-type and P-type elements each respectively have dimensions in length, width, and height ranging from about 125 microns to at least 3 millimeters.   
     
     
         49 . A method of making a thermoelectric device for converting thermal energy to electrical energy using electrically coupled doped semiconductive oxide ceramic elements to generate electricity based on temperature differences between portions of the device, comprising:
 forming a plurality of N-type elements, each comprising a doped semiconductive oxide ceramic element;   forming a plurality of P-type elements, each comprising a doped semiconductive oxide ceramic element, respectively paired with said plurality of N-type elements;   providing a pair of supporting ceramic rings forming concentric radial configurations having a generally open radially central portion adapted for exposure to a heat source with the radially exterior portion of the thermoelectric device adapted for exposure to an environment cooler than said heat source;   placing said paired N-type and P-type elements on selected portions of said ceramic rings so as to form a radial array of such pairs; and   electrically connecting said paired elements in series while said paired elements are thermally connected in parallel relative to said ceramic rings, 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.   
     
     
         50 . A method as in  claim 49 , wherein said electrically connecting includes directly brazing together the paired ends of said paired elements closer towards the radially central portion of said device, and soldering the other of the ends of said paired elements to one of said ceramic rings.