Thermoelectric device

Abstract

The present invention is directed to a thermoelectric device that includes a plurality of thermoelectric couples positioned between a top plate and a bottom plate, wherein each thermoelectric couple comprises n-type and p-type element assemblies electrically connected in series and thermally connected in parallel. When the device is used for electrical power generation, the efficiency is increased by using semiconductor materials with a high Seebeck coefficient, increasing the distance between the n-type and p-type element assemblies, increasing the length of the electrical conductors/thermal distance between the top and bottom plates, and/or using an insulation plate spaced from the top plate. When the device is used for heating/cooling, the coefficients of performance are increased by using semiconductor materials with a high Seebeck coefficient and/or optimizing the length of the electrical conductors/thermal distance between the top and bottom plates.

What is claimed and desired to be secured by Letters Patent is as follows: 
     
         1 . A method of making a thermoelectric device with an optimized figure of merit, comprising:
 providing a plurality of thermoelectric couples positioned between a top plate and a bottom plate to form the thermoelectric device, wherein the thermoelectric couples are electrically connected in series and thermally connected in parallel, wherein each of the thermoelectric couples comprises:
 an n-type element assembly comprising a first n-type semiconductor element formed of a first n-type material coupled to a first electrical connection and a second n-type semiconductor element formed of a second n-type material coupled to a second electrical connection, wherein the first electrical connection is connected to the second electrical connection via a first electrical conductor formed of a first conductive material and having a first length and a first diameter; 
 a p-type element assembly comprising a first p-type semiconductor element formed of a first p-type material coupled to a third electrical connection and a second p-type semiconductor element formed of a second p-type material coupled to a fourth electrical connection, wherein the third electrical connection is connected to the fourth electrical connection via a second electrical conductor formed of a second conductive material and having a second length and a second diameter; 
 wherein the n-type and p-type element assemblies are electrically connected in series and thermally connected in parallel; and 
   optimizing the figure of merit for the thermoelectric device by: (a) selecting the first and second n-type materials and the first and second p-type materials to optimize the figure of merit for a range of operating temperatures and (b) selecting the first and second conductive materials, the first and second lengths, and the first and second diameters to optimize the figure of merit when using the first and second n-type materials and the first and second p-type materials selected in step (a).   
     
     
         2 . The method of  claim 1 , wherein each of the first and second n-type materials has a Seebeck coefficient with a negative value greater than about −250 μV/° K and a thermal conductivity greater than about 0.1 W/cm·° K. 
     
     
         3 . The method of  claim 1 , wherein each of the first and second p-type materials has a Seebeck coefficient with a positive value greater than about 250 μV/° K and a thermal conductivity greater than about 0.1 W/cm·° K. 
     
     
         4 . The method of  claim 1 , wherein each of the first and second conductive materials has a ratio of electrical conductivity to thermal conductivity in a range of about 1.3×10 5  S° K/W to about 1.6×10 5  S° K/W. 
     
     
         5 . The method of  claim 1 , wherein each of the first and second lengths is in a range from about 2 cm to about 8 cm. 
     
     
         6 . The method of  claim 1 , wherein each of the first and second diameters is in a range from about 0.51054 mm (24 AWG) to about 3.66522 mm (7 AWG). 
     
     
         7 . The method of  claim 1 , wherein the n-type and p-type element assemblies of each of the thermoelectric couples are separated by a distance, and wherein the optimizing step includes selecting the distance to optimize the figure of merit. 
     
     
         8 . The method of  claim 7 , wherein the distance is in a range of about 0.05 cm to about 3.0 cm. 
     
     
         9 . The method of  claim 1 , wherein adjacent thermoelectric couples are separated by a distance, and wherein the optimizing step includes selecting the distance to optimize the figure of merit. 
     
     
         10 . The method of  claim 9 , wherein the distance is in a range of about 0.05 cm to about 3.0 cm. 
     
     
         11 . The method of  claim 1 , further comprising the step of providing an insulation plate above the top plate to reduce heat loss to ambient air. 
     
     
         12 . The method of  claim 11 , wherein air is located in a region between the insulating plate and the top plate. 
     
     
         13 . The method of  claim 11 , further comprising the step of maintaining a region between the insulating plate and the top plate at a gaseous pressure less than atmospheric pressure so as to create a vacuum. 
     
     
         14 . The method of  claim 11 , wherein air is located in a region between the insulating plate and the bottom plate. 
     
     
         15 . The method of  claim 11 , further comprising the step of maintaining a region between the insulating plate and the bottom plate at a gaseous pressure less than atmospheric pressure so as to create a vacuum. 
     
     
         16 . The method of  claim 11 , wherein the insulating plate is formed of glass or acrylic. 
     
     
         17 . The method of  claim 1 , wherein the top and bottom plates are each formed of polyphenylene sulfide (PPS) doped with boron nitride. 
     
     
         18 . The method of  claim 1 , wherein the top and bottom plates are each formed of ceramic doped with aluminum nitride. 
     
     
         19 . The method of  claim 1 , wherein the figure of merit provides a ZT value greater than about 5. 
     
     
         20 . The method of  claim 1 , wherein the figure of merit provides a ZT value greater than about 10. 
     
     
         21 . The method of  claim 1 , wherein the figure of merit provides a ZT value greater than about 15. 
     
     
         22 . The method of  claim 1 , wherein the figure of merit provides a ZT value greater than about 20. 
     
     
         23 . The method of  claim 1 , wherein the figure of merit provides a ZT value greater than about 25. 
     
     
         24 . The method of  claim 1 , wherein the figure of merit provides a ZT value greater than about 30. 
     
     
         25 . The method of  claim 1 , wherein the figure of merit provides a ZT value greater than about 35. 
     
     
         26 . The method of  claim 1 , wherein the figure of merit provides a ZT value greater than about 40. 
     
     
         27 . The method of  claim 1 , wherein the figure of merit provides a ZT value greater than about 45. 
     
     
         28 . The method of  claim 1 , wherein the figure of merit provides a ZT value greater than about 50. 
     
     
         29 . The method of  claim 1 , wherein the figure of merit provides an efficiency greater than about 15%. 
     
     
         30 . The method of  claim 1 , wherein the figure of merit provides an efficiency greater than about 20%. 
     
     
         31 . The method of  claim 1 , wherein the figure of merit provides an efficiency greater than about 30%. 
     
     
         32 . The method of  claim 1 , wherein the figure of merit provides an efficiency greater than about 40%. 
     
     
         33 . The method of  claim 1 , wherein the figure of merit provides an efficiency greater than about 50%. 
     
     
         34 . A thermoelectric device with an optimized figure of merit, comprising:
 a top plate spaced from a bottom plate; and   a plurality of thermoelectric couples positioned between the top and bottom plates, wherein the thermoelectric couples are electrically connected in series and thermally connected in parallel, wherein each of the thermoelectric couples comprises:
 an n-type element assembly comprising a first n-type semiconductor element formed of a first n-type material coupled to a first electrical connection and a second n-type semiconductor element formed of a second n-type material coupled to a second electrical connection, wherein the first electrical connection is connected to the second electrical connection via a first electrical conductor formed of a first conductive material, wherein each of the first and second n-type materials has a Seebeck coefficient with a negative value greater than about −250 μV/° K and a thermal conductivity greater than about 0.1 W/cm·° K, wherein the first conductive material has a ratio of electrical conductivity to thermal conductivity in a range of about 1.3×10 5  S° K/W to about 1.6×10 5  S° K/W; 
 a p-type element assembly comprising a first p-type semiconductor element formed of a first p-type material coupled to a third electrical connection and a second p-type semiconductor element formed of a second p-type material coupled to a fourth electrical connection, wherein the third electrical connection is connected to the fourth electrical connection via a second electrical conductor formed of a second conductive material, wherein each of the first and second p-type materials has a Seebeck coefficient with a positive value greater than about 250 μV/° K and a thermal conductivity greater than about 0.1 W/cm·° K, wherein the second conductive material has a ratio of electrical conductivity to thermal conductivity in a range of about 1.3×10 5  S° K/W to about 1.6×10 5  S° K/W; 
 wherein the n-type and p-type element assemblies are electrically connected in series and thermally connected in parallel. 
   
     
     
         35 . The thermoelectric device of  claim 34 , wherein each of the first and second electrical conductors has a length is in a range from about 2 cm to about 8 cm. 
     
     
         36 . The thermoelectric device of  claim 34 , wherein each of the first and second electrical conductors has a diameter in a range from about 0.51054 mm (24 AWG) to about 3.66522 mm (7 AWG). 
     
     
         37 . The thermoelectric device of  claim 34 , wherein the n-type and p-type element assemblies of each of the thermoelectric couples are separated by a distance in a range of about 0.05 cm to about 3.0 cm. 
     
     
         38 . The thermoelectric device of  claim 34 , wherein adjacent thermoelectric couples are separated by a distance in a range of about 0.05 cm to about 3.0 cm. 
     
     
         39 . The thermoelectric device of  claim 34 , further comprising an insulation plate above the top plate to reduce heat loss to ambient air. 
     
     
         40 . The thermoelectric device of  claim 39 , wherein air is located in a region between the insulating plate and the top plate. 
     
     
         41 . The thermoelectric device of  claim 39 , wherein a region between the insulating plate and the top plate is maintained at a gaseous pressure less than atmospheric pressure so as to create a vacuum. 
     
     
         42 . The thermoelectric device of  claim 39 , wherein air is located in a region between the insulating plate and the bottom plate. 
     
     
         43 . The thermoelectric device of  claim 39 , wherein a region between the insulating plate and the bottom plate is maintained at a gaseous pressure less than atmospheric pressure so as to create a vacuum. 
     
     
         44 . The thermoelectric device of  claim 34 , wherein the insulating plate is formed of glass or acrylic. 
     
     
         45 . The thermoelectric device of  claim 34 , wherein the top and bottom plates are each formed of polyphenylene sulfide (PPS) doped with boron nitride. 
     
     
         46 . The thermoelectric device of  claim 34 , wherein the top and bottom plates are each formed of ceramic doped with aluminum nitride.