Thermoelectric devices and applications for the same

• US 20050115601A1
• Filed: 12/02/2003
• Published: 06/02/2005
• Est. Priority Date: 12/02/2003
• Status: Active Grant

• Current Assignee: Battelle Memorial Institute
• Original Assignee: Battelle Memorial Institute
• Inventors: Martin, Peter M., Olsen, Larry C., DeSteese, John G., Johnston, John W.
• Granted Patent: US 8,455,751 B2
• Time in Patent Office: Days
• US Class Current: 136/212
• CPC Class Codes: H10N 10/817 the junction being non-separable, e.g. being cemented, sintered or soldered
• CPC Class Codes: H10N 10/852 comprising tellurium, selenium or sulfur

Abstract

High performance thin film thermoelectric couples and methods of making the same are disclosed. Such couples allow fabrication of at least microwatt to watt-level power supply devices operating at voltages greater than one volt even when activated by only small temperature differences.

Claims

1. a thermoelectric power source comprising:

a flexible substrate having an upper surface; and

a thermoelectric couple comprising;

(a) a sputter deposited thin film p-type thermoelement positioned on the upper surface of the flexible substrate;

(b) a sputter deposited thin film n-type thermoelement positioned on the upper surface of the flexible substrate adjacent the p-type thermoelement; and

(c) an electrically conductive member positioned on the flexible substrate, and electrically connecting the first end of the p-type thermoelement with the second end of the n-type thermoelement.

2. The thermoelectric power source of claim 1 wherein the p-type or the n-type thermoelements have L/A ratios greater than about 20 cm⁻

1.

3. The thermoelectric power source of claim 1 wherein the p-type or the n-type thermoelements have L/A ratios greater than about 100 cm⁻

1.

4. The thermoelectric power source of claim 1 wherein the p-type or the n-type thermoelements comprise Bi_aTe_b where a is about 2 and b is about 3.

5. The thermoelectric power source of claim 1 wherein the p-type or the n-type thermoelements are selected from the group Bi_xTe_y, Sb_xTe_y, and Bi_xSe_y alloys where x is about 2 and y is about 3.

6. The thermoelectric power source of claim 1 further comprising at least about 50 thermoelectric couples, wherein the thermoelectric power source has a power output of at least 1 μ

W with a voltage of at least at least 0.25 volt.

7. The thermoelectric power source of claim 6 wherein the p-type or the n-type thermoelements are at least about 1 mm in length and at least about 0.1 mm in width.

8. The thermoelectric power source of claim 6 wherein the p-type or the n-type thermoelements are at least about 20 angstroms in thickness.

9. The thermoelectric power source of claim 1 further comprising at least about 1000 thermoelectric couples, wherein the thermoelectric power source has a power output of about 1 W with a voltage of at least about 1 volt.

10. The thermoelectric power source of claim 1 wherein the p-type thermoelements have different widths as compared to the n-type thermoelements.

11. The thermoelectric power source of claim 1 wherein two or more p-type thermoelements are positioned and electrically connected in parallel with one another and the parallel positioned p-type thermoelements are electrically connected in series to n-type thermoelements.

12. The thermoelectric power source of claim 1 further including multiple thermoelectric couples electrically connected in series on the upper surface of the flexible substrate and wherein the flexible substrate is in a coil configuration.

13. The thermoelectric power source of claim 1 wherein the volume of the thermoelectric power source is less than about 10 cm³ and has a power output of from about 1 μ

W to about 1 W.

14. The thermoelectric power source of claim 1 wherein the volume of the thermoelectric power source is less than about 10 cm³ and provides voltages of greater than about 1 volt.

15. The thermoelectric power source of claim 14 wherein the thermoelectric power source produces power at temperature differences of about 20°

C. or less.

16. The thermoelectric power source of claim 1 wherein two or more n-type thermoelements are positioned and electrically connected in parallel with one another and the parallel positioned n-type thermoelements are electrically connected in series to p-type thermoelements.

17. The thermoelectric power source of claim 1 wherein the n-type thermoelements are substantially free of selenium.

18. The thermoelectric power source of claim 1 wherein the flexible substrate is a polyimide.

19. The thermoelectric power source of claim 1 wherein the p-type thermoelement is a superlattice.

20. The thermoelectric power source of claim 19 wherein the superlattice comprises alternating Bi₂Te₃ and Sb₂Te₃ layers with thicknesses between about 50 Å

and about 150 Å

.

21. The thermoelectric power source of claim 1 wherein the n-type thermoelement is a superlattice.

22. The thermoelectric power source of claim 21 wherein the superlattice comprises alternating Bi₂Te₃ and Sb₂Te₃ layers with thicknesses between about 50 Å

and about 150 Å

.

23. A thermoelectric power source comprising:

a flexible substrate having an upper surface;

multiple thermocouples electrically connected to one another on the upper surface of the flexible substrate, the thermocouples comprising;

sputter deposited thin film p-type thermoelements;

sputter deposited thin film n-type thermoelements alternatingly positioned adjacent the p-type thermoelements; and

wherein the thermoelectric power source has a volume of less than about 10 cm³ and has a power output of from about 1 μ

W to about 1 W.

24. The thermoelectric device of claim 23 wherein said multiple thermocouples electrically connected to one another in series or in series-parallel.

25. The thermoelectric power source of claim 23 wherein the p-type thermoelements have different widths as compared to the n-type thermoelements.

26. A method for fabricating thermoelectric power sources comprising:

providing a flexible substrate;

sputter depositing multiple thin films of n-type thermoelectric material onto the flexible substrate;

sputter depositing multiple thin films of p-type thermoelectric material onto the flexible substrate; and

forming multiple thermocouples on the flexible substrate by electrically connecting the thin films of p-type thermoelectric material to the thin films of n-type thermoelectric materials.

27. The method of claim 26 wherein the thermoelectric power source is fabricated to have a volume of less than about 10 cm³ and to provide voltages of greater than about 1 volt.

28. The method of claim 26 wherein the p-type or the n-type thermoelements are sputter deposited to have L/A ratios greater than about 50 cm⁻

1.

29. The method of claim 26 wherein the p-type or the n-type thermoelement materials are sputter deposited to have L/A ratios greater than about 20 cm⁻

1.

30. The method of claim 26 the p-type or the n-type thermoelement materials sputter deposited to form thin films of Bi_xTe_y, Sb_xTe_y, and Bi_xSe_y alloys where x is about 2 and y is about 3.

31. The method of claim 26 further comprising winding the flexible substrate into a coil configuration.

32. The method of claim 27 further comprising activating thermoelectric power source by a temperature gradient of about 20°

C. or less.

33. The method of claim 26 wherein targets used for sputter depositing a thin film of n-type or p-type thermoelectric material onto a flexible substrate comprise Sb₂Te₃ and Bi₂Te₃.

34. The method of claim 33 wherein an RF power of about 30 watts is supplied to the Sb₂Te₃ target and an RF power of about 10 watts is supplied to the Bi₂Te₃ target to sputter deposit the thin film of p-type thermoelectric material.

35. The method of claim 32 wherein an RF power of about 30 watts is supplied to the Sb₂Te₃ target and an RF power of about 20 watts is supplied to the Bi₂Te₃ target to sputter deposit the thin film of n-type thermoelectric material.

36. The method of claim 26 wherein a sputtering gas pressure is maintained at about 3 millitorr during the sputter deposition of the thin film of n-type thermoelectric material.