METHOD TO IMPROVE PV AESTHETICS AND EFFICIENCY

• US 20090255569A1
• Filed: 04/09/2009
• Published: 10/15/2009
• Est. Priority Date: 04/11/2008
• Status: Abandoned Application

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Sampsell, Jeffrey B., Kothari, Manish, Gruhlke, Russell Wayne
• Application Number:
  US12/421,400
• Publication Number:
  US 20090255569A1
• Time in Patent Office: Days
• US Class Current: 136/246
• CPC Class Codes: H01L 31/022425 for solar cells
• CPC Class Codes: H01L 31/0547 comprising light concentrating means of the reflecting type, e.g. parabolic mirrors, concentrators using total internal reflection
• CPC Class Codes: Y02E 10/52 PV systems with concentrators

Abstract

Various embodiments disclosed herein comprise a photovoltaic device of improved efficiency. The photovoltaic device comprises a photovoltaic material, a reflective conductor, a total-internal-reflection surface and a microstructure. The microstructure reflects light so that some of the reflected light is incident upon the total-internal-reflection surface at an angle greater than the critical angle. In some embodiments, the photovoltaic device has a photovoltaic material, a reflective conductor, and a surface forward the conductor configured to redirect light rays directed toward the conductor such that redirected light is instead incident on the photovoltaic material. Various embodiments include a method of manufacturing a photovoltaic device of improved efficiency. Other embodiments are also described.

Claims

1. A photovoltaic device having a forward side on which light is incident and a:

rearward side opposite the forward side, the photovoltaic device comprising;

a photovoltaic material;

a conductor in electrical contact with the photovoltaic material, wherein the conductor reflects incident light;

a total-internal-reflection surface disposed forward of the conductor and the photovoltaic material; and

microstructure rearward the total-internal-reflection surface, the microstructure configured to reflect light so that at least some reflected light is incident upon the total-internal-reflection surface at an angle greater than a critical angle of the total-internal-reflection surface.

2. The photovoltaic device of claim 1, wherein the microstructure comprises diffusing features of one or more diffusers.

3. The photovoltaic device of claim 2, wherein the diffuser scatters light over a range of angles greater than 90°

.

4. The photovoltaic device of claim 2, wherein the one or more diffusers comprises a spray-on diffuser and/or a diffusive white paint.

5. The photovoltaic device of claim 1, wherein the microstructure comprises diffracting features of one or more holograms.

6. The photovoltaic device of claim 1, wherein the microstructure comprises one or more diffractive features of a diffractive optical element.

7. The photovoltaic device of claim 1, further comprising a hologram or diffuser disposed forward the microstructure and rearward the total-internal-reflection surface.

8. The photovoltaic device of claim 1, wherein the microstructure comprises a surface of the conductor.

9. The photovoltaic device of claim 1, wherein a conductor aperture recovery is between about 30% to 65%.

10. The photovoltaic device of claim 1, wherein an efficiency of the photovoltaic device is 6% or more greater than the efficiency of the photovoltaic device without the microstructure.

11. A photovoltaic device having a forward side on which light is incident and a rearward side opposite the forward side, the photovoltaic device comprising:

means for generating electricity from incident light;

means for conducting electricity in electrical contact with the electricity generating means, wherein the conducting means reflects incident light;

means for totally internally reflecting light disposed forward of the conducting and the electricity generating means; and

means for reflecting light rearward the total-internal-reflecting means, the reflecting means configured to reflect light so that at least some reflected light is incident upon the total-internal-reflecting means at an angle greater than a critical angle of the total-internal-reflecting means.

12. The photovoltaic device of claim 11, wherein:

the electricity generating means comprises a photovoltaic material;

the conducting means comprises a conductor;

the total-internal-reflecting means comprises a total-internal-reflection surface;

or

the reflecting means comprises microstructure.

13. A photovoltaic device having a forward side on which light is incident and a rearward side opposite the forward side, the photovoltaic device comprising:

a photovoltaic material;

a conductor forward the photovoltaic material and in electrical contact with the photovoltaic material; and

a surface forward the conductor configured to redirect incident light rays directed toward the conductor such that redirected light is instead incident on the photovoltaic material.

14. The photovoltaic device of claim 13, wherein the surface comprises an element selected from the group consisting of holograms and diffusers.

15. The photovoltaic device of claim 13, wherein a conductor aperture recovery is between about 30% to 65%.

16. The photovoltaic device of claim 13, wherein an efficiency of the photovoltaic device is 6% or more greater than the efficiency of the photovoltaic device without the surface.

17. A photovoltaic device having a forward side on which light is incident and a rearward side opposite the forward side, the photovoltaic device comprising:

means for generating electricity from incident light;

means for conducting electricity forward the electricity generating means and in electrical contact with the electricity generating means; and

means for redirecting light forward the conducting means, the redirecting means configured to redirect incident light rays directed toward the conducting means such that redirected light is instead incident on the electricity generating means.

18. The photovoltaic device of claim 17, wherein

the electricity generating means comprises a photovoltaic material;

the conducting means comprises a conductor;

or

the redirecting means comprises a surface.

19. A method of manufacturing a photovoltaic device comprising:

providing a conductor disposed with respect to a photovoltaic material so as to be in electrical contact with the photovoltaic material, wherein the conductor reflects incident light;

disposing a total-internal-reflection surface forward of the conductor and the photovoltaic material; and

disposing microstructure rearward the total-internal-reflection surface, wherein the microstructure is configured to reflect light so that at least some reflected light is incident upon the total-internal-reflection surface at an angle greater than a critical angle of the total-internal-reflection surface.

20. The method of claim 19, wherein the conductor comprises an electrode on a photovoltaic cell.

21. The method of claim 19, wherein the conductor comprises a tab connecting a plurality of photovoltaic cells in an array.

22. The method of claim 19, wherein disposing the microstructure comprises forming the microstructure on a surface of the conductor.

23. The method of claim 22, wherein forming the microstructure on the surface of the conductor comprises a process selected from the group consisting of micro-embossing, micro-etching, plasma etching the reflective conductor, and holography.

24. The method of claim 19, wherein disposing the microstructure comprises embedding particles on the forward side of the conductor.

25. The method of claim 19, wherein disposing the microstructure comprises forming a diffuser film on the forward side of the conductor.

26. The method of claim 19, further comprising disposing a layer between the conductor and the microstructure.

27. The method of claim 26, wherein disposing the microstructure comprises disposing a scattering film over the layer and aligning the scattering film over the conductor.

28. A method of manufacturing a photovoltaic device comprising:

providing a conductor disposed with respect to a photovoltaic material so as to be in electrical contact with the photovoltaic material, wherein the conductor reflects incident light; and

disposing a surface forward the conductor, wherein the surface is configured to redirect incident light rays directed toward the conductor such that redirected light is instead incident on the photovoltaic material.

29. The method of claim 28, wherein the surface comprises an element selected from the group consisting of holograms and diffusers.

30. The method of claim 28, wherein the surface comprises a tape.

31. The method of claim 28, further comprising patterning the surface to align with a pattern of the conductor.

32. The method of claim 28, wherein an efficiency of the photovoltaic device is 6% or more greater than the efficiency of the photovoltaic device without the surface.

33. A photovoltaic array having a forward side on which light is incident and a rearward side opposite the forward side, the photovoltaic array comprising:

a gap between two spaced apart pieces of photovoltaic material; and

a surface forward the gap configured to redirect incident light rays directed toward the gap such that redirected light is instead incident on the photovoltaic material.

34. The array of claim 33, wherein the surface reflects light such that the light is subsequently totally-internally reflected toward the photovoltaic material.

35. The device of claim 33, wherein the surface deflects transmitted light toward the photovoltaic material.

36. A photovoltaic device having a forward side on which light is incident and a rearward side opposite the forward side, the photovoltaic device comprising:

a gap between two spaced apart means for generating electricity; and

means for redirecting light forward the gap, the redirecting means configured to redirect incident light rays directed toward the gap such that redirected light is instead incident on the electricity generating means.

37. The photovoltaic device of claim 36, wherein

the electricity generating means comprises a photovoltaic material;

the redirecting means comprises a reflecting element;

or the redirecting means comprises a refracting element.

38. A method of manufacturing a photovoltaic device comprising:

disposing a surface forward a gap between spaced apart pieces of photovoltaic material, wherein the surface is configured to redirect incident light rays directed toward the gap such that redirected light is instead incident on the photovoltaic material.

39. The method of claim 38, wherein the surface comprises a reflective or refractive element.