Miniature thermoelectric power generator

• US 9,214,618 B2
• Filed: 09/11/2009
• Issued: 12/15/2015
• Est. Priority Date: 09/18/2008
• Status: Active Grant

• Current Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Original Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Inventors: Arnold, David Patrick, Boniche, Israel, Meyer, Christopher David, Masilamani, Sivaraman
• Primary Examiner(s): Ayad, Tamir
• Application Number:
  US13/061,422
• Publication Number:
  US 20110155202A1
• Time in Patent Office: 2,286 Days
• Field of Search: 136/201, 136/224
• US Class Current: 1/1
• CPC Class Codes: H10N 10/17 characterised by the structure or configuration of the cell or thermocouple forming the device

Abstract

The subject invention pertains to thermoelectric power generation. According to certain embodiments, a stack of silicon-micromachined chips can be connected to form a cylindrical heat exchanger that enables a large, uniform temperature difference across a radially-oriented thermopile. Each layer in the stack can comprise two thermally-isolated concentric silicon rings connected by a polyimide membrane that supports patterned thermoelectric thin films. The polyimide membrane can be formed by selectively etching away the supporting silicon, resulting in thermally-isolated inner and outer rings. In operation, hot gas can flow through a finned central channel, and an external cross flow can enhance heat transfer to ambient to keep the outer surfaces cool. The resulting temperature gradient across the thermopile generates a voltage potential across the open ends due to the Seebeck effect. When connected to a load, current flows, and electrical power is supplied by the generated voltage potential caused by the temperature gradient.

Claims

1. A thermoelectric device, comprising:

a stack of thermoelectric modules, each thermoelectric module comprising;

an inner thermally conductive ring, the inner thermally conductive ring providing a channel for hot gas to pass therethrough;

an outer thermally conductive ring, an outer surface of the outer thermally conductive ring remaining cooler than the inner thermally conductive ring;

a radially-oriented thermopile in connection with the inner thermally conductive ring and the outer thermally conductive ring, wherein the radially-oriented thermopile has azimuthally alternating L-shaped regions of thermoelectric material in a direction following a circumference of the outer thermally conductive ring, each L-shaped region overlapping a portion of the adjacent L-shaped region; and

an annular supporting membrane perpendicular to the channel, wherein the annular supporting membrane is disposed between the radially-oriented thermopile and a top surface of the inner and outer thermally conductive rings, and wherein each top surface of the inner and outer thermally conductive rings is perpendicular to the channel, wherein the annular supporting membrane comprises a thermally insulating material.

2. The thermoelectric device according to claim 1, wherein the outer surface of the outer thermally conductive ring remains cool through exposure to an external environment by passive exposure or by convective flow.

3. The thermoelectric device according to claim 1, wherein each thermoelectric module further comprises:

inner fins on an inner surface of the inner conductive ring.

4. The thermoelectric device according to claim 3, wherein the inner fins extend longitudinally along the inner surface.

5. The thermoelectric device according to claim 3, wherein the inner fins comprise pin shapes extending perpendicular to the inner surface.

6. The thermoelectric device according to claim 1, wherein certain ones of the thermoelectric modules of the stack comprise a fin extension at the outer conductive ring.

7. The thermoelectric device according to claim 1, wherein the inner thermally conductive ring and the outer thermally conductive ring comprise silicon.

8. The thermoelectric device according to claim 1, wherein the alternating regions of thermoelectric material comprise a first metal as one thermoelectric material and a second metal different than the first metal as another thermoelectric material.

9. The thermoelectric device according to claim 1, wherein the alternating regions of thermoelectric material comprise a metal as one thermoelectric material and polysilicon as another thermoelectric material.

10. The thermoelectric device according to claim 1, wherein the alternating regions of thermoelectric material comprise at least one of bismuth telluride alloy, lead telluride alloy, silicon germanium alloy, TAGS, and LAST.

11. The thermoelectric device according to claim 1, further comprising resistive temperature sensors on the inner thermally conductive ring and the outer thermally conductive ring.

12. A thermoelectric device, comprising:

a stack of thermoelectric modules, each thermoelectric module comprising;

an inner thermally conductive ring, the inner thermally conductive ring providing a channel for hot gas to pass therethrough;

an outer thermally conductive ring, an outer surface of the outer thermally conductive ring remaining cooler than the inner thermally conductive ring;

a radially-oriented thermopile in connection with the inner thermally conductive ring and the outer thermally conductive ring, wherein the radially-oriented thermopile has azimuthally alternating regions of thermoelectric material in a direction following a circumference of the outer thermally conductive ring; and

an annular supporting membrane perpendicular to the channel and in overlying relationship with a top surface of the inner and outer thermally conductive rings and, wherein the radially-oriented thermopile is disposed on the annular supporting membrane and each top surface of the inner and outer thermally conductive rings is perpendicular to the channel;

wherein the inner and outer thermally conductive rings comprise silicon; and

wherein the annular supporting membrane comprises;

a silicon dioxide pattern on a top surface of the silicon inner and outer thermally conductive rings; and

an annular polyimide membrane on the silicon dioxide pattern, wherein the radially-oriented thermopile is disposed on the annular polyimide membrane.

13. A thermoelectric device, comprising:

a stack of thermoelectric modules, each thermoelectric module comprising;

an inner thermally conductive ring, the inner thermally conductive ring providing a channel for hot gas to pass therethrough;

an outer thermally conductive ring, an outer surface of the outer thermally conductive ring remaining cooler than the inner thermally conductive ring;

a radially-oriented thermopile perpendicular to the channel and in overlying relationship with a top surface of the inner thermally conductive ring and a top surface of the outer thermally conductive ring, wherein the radially-oriented thermopile has azimuthally alternating L-shaped regions of thin-film thermoelectric material in a direction following a circumference of the outer thermally conductive ring, each L-shaped region of the adjacent L-shaped region; and

an annular supporting membrane perpendicular to the channel, wherein the annular supporting membrane is disposed between the radially-oriented thermopile and a top surface of the inner and outer thermally conductive rings,

wherein each top surface of the inner and outer thermally conductive rings is perpendicular to the channel, and wherein the annular supporting membrane comprises a thermally insulating material.