Flexible encapsulation of a flexible thin-film based thermoelectric device with sputter deposited layer of N-type and P-type thermoelectric legs

• US 10,553,773 B2
• Filed: 01/11/2018
• Issued: 02/04/2020
• Est. Priority Date: 12/06/2013
• Status: Active Grant

• Current Assignee: Nimbus Materials Inc
• Original Assignee: Sridhar Kasichainula
• Inventors: Kasichainula, Sridhar
• Primary Examiner(s): Garber, Charles D
• Assistant Examiner(s): Sabur, Alia
• Application Number:
  US15/869,017
• Publication Number:
  US 20180159015A1
• Time in Patent Office: 754 Days
• CPC Class Codes: H02S 10/10 including a supplementary source of electric power, e.g. hybrid diesel-PV energy systems combinations with gas-turbine plants F02C6/00
• CPC Class Codes: H02S 10/30 Thermophotovoltaic systems photovoltaic cells specially adapted for conversion or sensing of infrared [IR] radiation H01L31/00; thermoelectric devices H10N10/00
• CPC Class Codes: H02S 10/40 Mobile PV generator systems
• CPC Class Codes: H10N 10/01 Manufacture or treatment
• CPC Class Codes: H10N 10/13 characterised by the heat-exchanging means at the junction
• CPC Class Codes: H10N 10/17 characterised by the structure or configuration of the cell or thermocouple forming the device
• CPC Class Codes: H10N 10/817 the junction being non-separable, e.g. being cemented, sintered or soldered
• CPC Class Codes: H10N 19/00 Integrated devices, or assemblies of multiple devices, comprising at least one thermoelectric or thermomagnetic element covered by groups H10N10/00 - H10N15/00
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y02E 10/52 PV systems with concentrators

Abstract

A method of encapsulating a thin-film based thermoelectric module includes forming the thin-film based thermoelectric module by sputter depositing pairs of N-type thermoelectric legs and P-type thermoelectric legs electrically in contact with one another on a flexible substrate having a dimensional thickness less than or equal to 25 μm, and rendering the formed thin-film based thermoelectric module flexible and less than or equal to 100 μm in dimensional thickness based on choices of fabrication processes with respect to layers of the formed thin-film based thermoelectric module. The method also includes encapsulating the formed thin-film based thermoelectric module with an elastomer to render the flexibility thereto. The elastomer encapsulation has a dimensional thickness less than or equal to 15 μm, and the flexibility enables an array of thin-film based thermoelectric modules to be completely wrappable and bendable around a system element from which the array is configured to derive thermoelectric power.

Claims

1. A method of encapsulating a thin-film based thermoelectric module, comprising:

forming the thin-film based thermoelectric module by sputter depositing pairs of N-type thermoelectric legs and P-type thermoelectric legs electrically in contact with one another on a flexible substrate, the flexible substrate being one of;

aluminum (Al) foil, a sheet of paper, teflon, plastic, a single-sided copper (Cu) clad laminate sheet, and a double-sided Cu clad laminate sheet, and the flexible substrate having a dimensional thickness less than or equal to 25 μ

m;

rendering the formed thin-film based thermoelectric module flexible and less than or equal to 100 μ

m in dimensional thickness based on choices of fabrication processes with respect to layers of the formed thin-film based thermoelectric module including the sputter deposited N-type thermoelectric legs and the P-type thermoelectric legs; and

encapsulating the formed thin-film based thermoelectric module with an elastomer to render the flexibility thereto, the elastomer encapsulation having a dimensional thickness less than or equal to 15 μ

m, the flexibility enabling an array of thin-film based thermoelectric modules, each of which is equivalent to the thin-film based thermoelectric module formed on the flexible substrate with the elastomer encapsulation, to be completely wrappable and bendable around a system element from which the array of the thin-film based thermoelectric modules is configured to derive thermoelectric power, and a layer of the formed thin-film based thermoelectric module including the sputter deposited N-type thermoelectric legs and the P-type thermoelectric legs having a dimensional thickness less than or equal to 25 μ

m.

2. The method of claim 1, comprising encapsulating the formed thin-film based thermoelectric module with one of:

Room-Temperature-Vulcanizing (RTV) silicone and a mixture of RTV silicone and a thinner as the elastomer.

3. The method of claim 1, further comprising curing the elastomer encapsulating the formed thin-film based thermoelectric module at 150°

C.

4. The method of claim 1, comprising encapsulating the formed thin-film based thermoelectric module with the elastomer based on one of:

doctor blading and spin coating.

5. The method of claim 1, further comprising mixing RTV silicone with finely dispersed finely dispersed nano-sized Alumina (Al₂O₃) particles as the elastomer to improve thermal conductivity thereof in accordance with the elastomer having an effective thermal conductivity K_eff=V₁K₁+V₂K₂,

wherein V₁ is the volume fraction of the RTV silicone, V₂ is the volume fraction of the finely dispersed nano-sized Al₂O₃ particles, K₁ is the thermal conductivity of the RTV silicone, and K₂ is the thermal conductivity of Al₂O₃.

6. The method of claim 1, further comprising:

depositing a moisture barrier thin film on the formed thin-film based thermoelectric module prior to the encapsulation thereof with the elastomer; and

providing the encapsulation through the elastomer around the deposited moisture barrier thin film.

7. The method of claim 6, comprising depositing a thin film of one of:

Silicon Nitride (Si₃N₄) and Alumina (Al₂O₃) as the moisture barrier thin film.

8. A method of a thin-film based thermoelectric module, comprising:

forming the thin-film based thermoelectric module by sputter depositing pairs of N-type thermoelectric legs and P-type thermoelectric legs electrically in contact with one another on a flexible substrate, the flexible substrate being one of;

Al foil, a sheet of paper, teflon, plastic, a single-sided Cu clad laminate sheet, and a double-sided Cu clad laminate sheet, and the flexible substrate having a dimensional thickness less than or equal to 25 μ

m;

rendering the formed thin-film based thermoelectric module flexible and less than or equal to 100 μ

m in dimensional thickness based on choices of fabrication processes with respect to layers of the formed thin-film based thermoelectric module including the sputter deposited N-type thermoelectric legs and the P-type thermoelectric legs, a layer of the formed thin-film based thermoelectric module including the sputter deposited N-type thermoelectric legs and the P-type thermoelectric legs having a dimensional thickness less than or equal to 25 μ

m;

encapsulating the formed thin-film based thermoelectric module with an elastomer to render the flexibility thereto, the elastomer encapsulation having a dimensional thickness less than or equal to 15 μ

m; and

wrapping and bending an array of thin-film based thermoelectric modules, each of which is equivalent to the thin-film based thermoelectric module formed on the flexible substrate with the elastomer encapsulation, completely around a system element from which the array of the thin-film based thermoelectric modules is configured to derive thermoelectric power in accordance with the flexibility thereof.

9. The method of claim 8, comprising encapsulating the formed thin-film based thermoelectric module with one of:

RTV silicone and a mixture of RTV silicone and a thinner as the elastomer.

10. The method of claim 8, further comprising curing the elastomer encapsulating the formed thin-film based thermoelectric module at 150°

C.

11. The method of claim 8, comprising encapsulating the formed thin-film based thermoelectric module with the elastomer based on one of:

doctor blading and spin coating.

12. The method of claim 8, further comprising mixing RTV silicone with finely dispersed finely dispersed nano-sized Al₂O₃ particles as the elastomer to improve thermal conductivity thereof in accordance with the elastomer having an effective thermal conductivity K_eff=V₁K₁+V₂K₂,

wherein V₁ is the volume fraction of the RTV silicone, V₂ is the volume fraction of the finely dispersed nano-sized Al₂O₃ particles, K₁ is the thermal conductivity of the RTV silicone, and K₂ is the thermal conductivity of Al₂O₃.

13. The method of claim 8, further comprising:

depositing a moisture barrier thin film on the formed thin-film based thermoelectric module prior to the encapsulation thereof with the elastomer; and

providing the encapsulation through the elastomer around the deposited moisture barrier thin film.

14. The method of claim 13, comprising depositing a thin film of one of:

Si₃N₄ and Al₂O₃ as the moisture barrier thin film.

15. A method of a thin-film based thermoelectric device comprising:

forming the thin-film based thermoelectric device out of an array of thermoelectric modules, each of which is less than or equal to 100 μ

m in dimensional thickness and is formed by sputter depositing pairs of N-type thermoelectric legs and P-type thermoelectric legs electrically in contact with one another on a flexible substrate, the flexible substrate being one of;

Al foil, a sheet of paper, teflon, plastic, a single-sided Cu clad laminate sheet, and a double-sided Cu clad laminate sheet, the flexible substrate having a dimensional thickness less than or equal to 25 μ

m, and a layer of the each thermoelectric module including the sputter deposited N-type thermoelectric legs and the P-type thermoelectric legs having a dimensional thickness less than or equal to 25 μ

m;

rendering the formed thin-film based thermoelectric device flexible based on choices of fabrication processes with respect to layers of the each thermoelectric module including the sputter deposited N-type thermoelectric legs and the P-type thermoelectric legs; and

encapsulating the each thermoelectric module of the formed thin-film based thermoelectric device with an elastomer to render the flexibility thereto, the elastomer encapsulation having a dimensional thickness less than or equal to 15 μ

m, and the flexibility enabling the formed thin-film based thermoelectric device to be completely wrappable and bendable around a system element from which the formed thin-film based thermoelectric device is configured to derive thermoelectric power.

16. The method of claim 15, comprising encapsulating the each thermoelectric module with one of:

RTV silicone and a mixture of RTV silicone and a thinner as the elastomer.

17. The method of claim 15, comprising encapsulating the each thermoelectric module with the elastomer based on one of:

doctor blading and spin coating.

18. The method of claim 15, further comprising mixing RTV silicone with finely dispersed finely dispersed nano-sized Al₂O₃ particles as the elastomer to improve thermal conductivity thereof in accordance with the elastomer having an effective thermal conductivity K_eff=V₁K₁+V₂K₂,

wherein V₁ is the volume fraction of the RTV silicone, V₂ is the volume fraction of the finely dispersed nano-sized Al₂O₃ particles, K₁ is the thermal conductivity of the RTV silicone, and K₂ is the thermal conductivity of Al₂O₃.

19. The method of claim 15, further comprising:

depositing a moisture barrier thin film on the each thermoelectric module prior to the encapsulation thereof with the elastomer; and

providing the encapsulation through the elastomer around the deposited moisture barrier thin film.

20. The method of claim 19, comprising depositing a thin film of one of:

Si₃N₄ and Al₂O₃ as the moisture barrier thin film.