FLEXIBLE THERMOELECTRIC GENERATOR AND METHOD FOR FABRICATING THE SAME

• US 20200136005A1
• Filed: 10/17/2019
• Published: 04/30/2020
• Est. Priority Date: 10/26/2018
• Status: Active Grant

• Current Assignee: Nano and Advanced Materials Institute Limited
• Original Assignee: Nano and Advanced Materials Institute Limited
• Inventors: SUN, Xinying, WANG, Han, XIN, Jianzhuo, LI, Jifan
• Granted Patent: US 11,024,788 B2
• Time in Patent Office: Days
• CPC Class Codes: H10N 10/01 Manufacture or treatment
• CPC Class Codes: H10N 10/17 characterised by the structure or configuration of the cell or thermocouple forming the device

Abstract

The present disclosure provides a thermoelectric generator and methods for fabricating the same. The semiconductor legs and electrodes of the thermoelectric generator are embedded in one or more flexible polymer matrices providing protection to the semiconductor legs and electrodes to maintain good electric contacts among them during bending. Thus, the output power of the thermoelectric generator can be substantially retained even after a large number of bending cycles.

Claims

1. A thermoelectric generator comprising:

an thermoelectric conversion layer having a first surface and a second surface and comprising a plurality of p-type semiconductor legs, a plurality of n-type semiconductor legs and a first flexible polymer matrix having a first thermal conductivity, wherein the first surface is opposite to the second surface, the plurality of p-type semiconductor legs and the plurality of n-type semiconductor legs define a plurality of thermoelectric couples and are embedded in the first flexible polymer matrix in a way that both ends of each p-type semiconductor leg are exposed to the first surface and the second surface respectively, both ends of each n-type semiconductor leg are exposed to the first surface and the second surface respectively, and the plurality of p-type semiconductor legs and the plurality of n-type semiconductor legs are separated by the first flexible polymer matrix;

a plurality of first electrodes located on the first surface and coupled to the plurality of thermoelectric couples;

a first flexible layer comprising a second flexible polymer matrix having a second thermal conductivity and covering the plurality of first electrodes and an exposed area of the first surface, the exposed area of the first surface is an area not covered by the plurality of first electrodes, such that the first surface is covered by the plurality of first electrodes and the second flexible polymer matrix;

a plurality of second electrodes located on the second surface and coupled to the plurality of thermoelectric couples; and

a second flexible layer comprising a third flexible polymer matrix having a third thermal conductivity and covering the plurality of second electrodes and an exposed area of the second surface, the exposed area of the second surface is an area not covered by the plurality of second electrodes, such that the second surface is covered by the plurality of second electrodes and the third flexible polymer matrix.

2. The thermoelectric generator of claim 1, wherein both of the second thermal conductivity and the third thermal conductivity are higher than the first thermal conductivity.

3. The thermoelectric generator of claim 1, wherein the first thermal conductivity is between 0.1 W/mK and 0.5 W/mK, the second thermal conductivity is between 0.5 W/mK and 3 W/mK, the third thermal conductivity is between 0.5 W/mK and 3 W/mK.

4. The thermoelectric generator of claim 1, wherein the first flexible polymer matrix has a composition comprising a first polymer, and both of the second flexible polymer matrix and the third flexible polymer matrix have a composition comprising a second polymer and one or more fillers.

5. The thermoelectric generator of claim 4, wherein the first polymer is polydimethylsiloxane (PDMS), thermoplastic polyurethane (TPU), or ethylene-vinyl acetate copolymer (EVA), and the second polymer is PDMS, TPU, EVA, or polyimide (PI).

6. The thermoelectric generator of claim 4, wherein the one or more fillers are silicon carbide (SiC), boron nitride (BN), aluminum oxide (Al₂O₃), aluminum nitride (AlN), graphite, a carbon nanotube (CNT), or a combination thereof.

7. The thermoelectric generator of claim 4, wherein the first polymer is PDMS, the second polymer is PDMS, the one or more fillers have two fillers including a combination of BN and AIN, a combination of BN and SiC, or a combination of AlN+Al₂O₃.

8. The thermoelectric generator of claim 1, wherein the thermoelectric generator has a thickness between 4.0 mm and 4.5 mm, the first flexible layer has a thickness between 1.5 mm and 1.0 mm, and the second flexible layer has a thickness between 1.5 mm and 1.0 mm.

9. The thermoelectric generator of claim 1, wherein the each p-type semiconductor leg comprises bismuth telluride (Bi₂Te₃), bismuth selenide (Bi₂Se₃), antimony telluride (Sb₂Te₃), (Bi,Sb)₂Te₃, iron antimonide (FeSb₂), lead telluride (PbTe), tin selenide (SnSe), or bismuth antimonide (BiSb), the each n-type semiconductor leg comprises Bi₂Te₃, Bi₂Se₃, Sb₂Te₃, (Bi,Sb)2Te₃, FeSb₂, PbTe, SnSe, or BiSb.

10. The thermoelectric generator of claim 1, wherein the each p-type semiconductor leg has a size of 1.2×

1.2×

2.0 mm³, and the each n-type semiconductor leg has a size of 1.2×

1.2×

2.0 mm³.

11. The thermoelectric generator of claim 1, wherein the each first electrode comprises copper (Cu), silver (Ag), gallium-indium eutectic (EGaIn), or a conductive fabric, and the each second electrode comprises Cu, Ag, EGaIn, or the conductive fabric.

12. The thermoelectric generator of claim 1 further comprising a flexible heat dissipation layer attaching on the first flexible layer or the second flexible layer.

13. The thermoelectric generator of claim 12, wherein the flexible heat dissipation layer comprises a super absorption polymer, a cooling fabric, a water absorption paper, a phase change material, a metal foam, or a thermal conductive glue.

14. A method for fabricating the thermoelectric generator of claim 1 comprising:

arranging the plurality of p-type semiconductor legs and the plurality of n-type semiconductor legs in an array;

inserting a solution of the first flexible polymer matrix among the plurality of p-type semiconductor legs and the plurality of n-type semiconductor legs;

curing the solution of the first flexible polymer matrix thereby forming the thermoelectric conversion layer;

forming the plurality of first electrodes on the first surface;

forming the first flexible layer on the plurality of first electrodes and the exposed area of the first surface;

forming the plurality of second electrodes on the second surface; and

forming the second flexible layer on the plurality of second electrodes and the exposed area of the second surface.

15. The method of claim 14, wherein the step of forming the first flexible layer comprises:

inserting a solution of the second flexible polymer matrix on the plurality of first electrodes and the exposed area of the first surface; and

curing the solution of the second flexible polymer matrix thereby forming the first flexible layer.

16. The method of claim 14, wherein the step of forming the second flexible layer comprises:

inserting a solution of the third flexible polymer matrix on the plurality of second electrodes and the exposed area of the second surface; and

curing the solution of the third flexible polymer matrix thereby forming the second flexible layer.

17. A thermoelectric generator comprising:

an thermoelectric conversion layer having a first surface and a second surface, and comprising a plurality of p-type semiconductor legs, a plurality of n-type semiconductor legs, and a flexible polymer matrix, wherein the first surface is opposite to the second surface, the plurality of p-type semiconductor legs and the plurality of n-type semiconductor legs define a plurality of thermoelectric couples and are embedded in the flexible polymer matrix in a way that both ends of each p-type semiconductor leg are exposed to the first surface and the second surface respectively, both ends of each n-type semiconductor leg are exposed to the first surface and the second surface respectively, and the plurality of p-type semiconductor legs and the plurality of n-type semiconductor legs are separated by the flexible polymer matrix; and

a plurality of first electrode columns located on the first surface and arranged in parallel with a first axis of bending of the thermoelectric generator, each first electrode column comprising a plurality of first electrodes and a first flexible layer, the plurality of first electrodes being attached on the first flexible layer in at least one column and coupled to their respective thermoelectric couples.

18. The thermoelectric generator of claim 17 further comprising:

a plurality of second electrode columns located on the second surface and arranged in parallel with a second axis of bending of the thermoelectric generator, each second electrode column comprising a plurality of second electrodes and a second flexible layer, the plurality of second electrodes being attached on the second flexible layer in at least one column and coupled to their respective thermoelectric couples, the second axis of bending being perpendicular to the first axis of bending.

19. The thermoelectric generator of claim 17 further comprising:

a plurality of second electrodes located on the second surface and coupled to the plurality of thermoelectric couples; and

a second flexible layer covering the plurality of second electrodes.

20. A method for fabricating the thermoelectric generator of claim 18 comprising:

arranging the plurality of p-type semiconductor legs and the plurality of n-type semiconductor legs in an array;

inserting a solution of the flexible polymer matrix among the plurality of p-type semiconductor legs and the plurality of n-type semiconductor legs;

curing the solution of the flexible polymer matrix thereby forming the thermoelectric conversion layer;

forming the plurality of first electrodes on a first substrate layer, the first substrate layer having the same material and thickness of each first flexible layer;

attaching the plurality of first electrodes on the first substrate layer to the first surface of the thermoelectric conversion layer;

separating the first substrate layer along the first axis of bending thereby forming the plurality of first electrode columns;

forming the plurality of second electrodes on a second substrate layer, the second substrate layer having the same material and thickness of each second flexible layer;

attaching the plurality of second electrodes on the second substrate layer to the second surface of the thermoelectric conversion layer; and

separating the second substrate layer along the second axis of bending thereby forming the plurality of second electrode columns.