Laminated Solar Concentrating Photovoltaic Device

• US 20070256726A1
• Filed: 05/05/2006
• Published: 11/08/2007
• Est. Priority Date: 05/05/2006
• Status: Active Grant

• Current Assignee: Solfocus, Inc., Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Inventors: Horne, Stephen, Fork, David
• Granted Patent: US 7,638,708 B2
• Time in Patent Office: Days
• US Class Current: 136/246
• CPC Class Codes: H01L 31/052 Cooling means directly associated or integrated with the PV cell, e.g. integrated Peltier elements for active cooling or heat sinks directly associated with the PV cells cooling means in combination with the PV module H02S40/42
• 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

A solar concentrator photovoltaic (CPV) device in which concentrator elements (optics, PV cells and wiring) are laminated to form a composite, substantially planar structure. The concentrator optics are implemented by a solid (e.g. glass) optical element that defines a focal point at which solar light received by the optical element is concentrated. Using vacuum lamination techniques, a printed circuit structure attached by way of an adhesive layer onto a surface of the optical element. The printed circuit structure includes one or more non-conductive layers and conductors that are disposed on the non-conductive layers. The PV cell is connected to printed circuit structure, and is positioned at the focal point of the optical element. Optional front and/or back protective layers are also attached prior to the lamination process. A CPV array includes multiple devices formed on an optical tile using a string-like flexible printed circuit structure.

Claims

1. A concentrating photovoltaic (CPV) device comprising:

a solid, light-transparent optical element having opposing first and second surfaces and defining a focal point at which light received by the optical element is concentrated;

a photovoltaic (PV) cell disposed at the focal point; and

a backsheet fixedly mounted over the first surface of the optical element, the backsheet including a printed circuit structure and a first adhesive layer disposed between the printed circuit structure and the first surface,

wherein the printed circuit structure includes one or more non-conductive layers and first and second conductors disposed on the non-conductive layers, and

wherein the PV cell includes first and second terminals respectively electrically connected to the first and second conductors of the printed circuit structure.

2. The CPV device according to claim 1,

wherein the optical element includes a relatively large convex surface defining a central cavity, and an opposing aperture surface and a relatively small curved surface defined in a central portion of the aperture surface, and

wherein the optical element further comprises a primary mirror disposed between the convex surface and the first adhesive layer, and a secondary mirror disposed on the curved surface,

wherein the primary and secondary mirrors are arranged such that light entering the optical element through the aperture surface is concentrated inside the central cavity on said PV cell.

3. The CPV device according to claim 2, wherein the printed circuit structure includes a central portion disposed over the central cavity of the optical element, and one or more peripheral portions extending from the central portion over the convex surface.

4. The CPV device according to claim 3, wherein a first thickness of the first adhesive layer adjacent to the central cavity is less than a second thickness adjacent to a peripheral edge of the convex surface.

5. The CPV device according to claim 3, wherein a first thickness of the backsheet adjacent to the central cavity is less than a second thickness adjacent to a peripheral edge of the convex surface.

6. The CPV device according to claim 3, further comprising an optically transparent material disposed in the central cavity between the central portion of the printed circuit structure and an adjacent surface of the optical element.

7. The CPV device according to claim 6, further comprising a heat slug disposed in the central cavity and electrically connected between at least one of the first and second terminals of the PV device and at least one of the first and second conductors of the printed circuit structure.

8. The CPV device according to claim 3, wherein the one or more peripheral portions of the printed circuit board comprise a plurality of radial arms extending from the central portion, wherein each adjacent pair of radial arms are separated by an associated slit.

9. The CPV device according to claim 1,

wherein the one or more non-conductive layers of the printed circuit structure comprise a flexible polyimide film, and

wherein the first and second conductors of the printed circuit structure comprise one of copper and Fe—

Ni alloy disposed on the flexible polyimide film.

10. The CPV device according to claim 9,

wherein the second conductor is disposed between the first conductor and the optical element, and

wherein a mass per unit area of the second conductor is greater than a mass per unit area of the first conductor.

11. The CPV device according to claim 1, wherein the first adhesive layer comprises ethylene vinyl acetate copolymers.

12. The CPV device according to claim 1, wherein the laminated backsheet further comprises a protective shell layer disposed on a backside surface of the printed circuit structure, and a second adhesive layer disposed between the backside surface of the printed circuit structure and the protective shell layer.

13. The CPV device according to claim 12, wherein the protective shell layer comprises a relatively high melting point plastic material, and wherein the second adhesive layer comprises ethylene vinyl acetate copolymers.

14. The CPV device according to claim 1, further comprising a transparent coversheet disposed over the aperture surface and the secondary mirror, and a third adhesive layer disposed between the transparent coversheet and the aperture surface.

15. The CPV device according to claim 14, wherein transparent coversheet comprises tempered glass and wherein the third adhesive layer comprises ethylene vinyl acetate copolymers.

16. The CPV device according to claim 15, wherein transparent coversheet comprises one of an antireflective coating and means for rejecting radiation having one or more predetermined wavelengths.

17. A laminated concentrating solar collector array comprising:

a solid, light-transparent optical tile having opposing first and second surfaces and including a plurality of optical elements, each optical element defining a focal point at which light received by the optical element is concentrated;

a plurality of photovoltaic (PV) cells, each PV cell being disposed at the focal point of an associated optical element; and

a backsheet fixedly mounted over the first surface of the optical tile, the backsheet including a printed circuit array and a first adhesive layer disposed between the printed circuit array and the first surface,

wherein the printed circuit array includes one or more non-conductive layers and first and second conductors disposed on the non-conductive layers, and

wherein each PV cell includes first and second terminals respectively electrically connected to the first and second conductors of the printed circuit structure.

18. The laminated concentrating solar collector array according to claim 17, wherein the printed circuit array comprises:

a plurality of printed circuit structures, each printed circuit structure including a central portion having an associated PV cell mounted thereon; and

a plurality of extensible structures connected between adjacent pairs of said printed circuit structures.

19. A method for producing a concentrating photovoltaic (CPV) device comprising:

forming a solid, light-transparent optical element having opposing first and second surfaces and defining a focal point at which light received by the optical element is concentrated;

forming a printed circuit structure including one or more non-conductive layers and first and second conductors disposed on the non-conductive layers;

mounting a photovoltaic (PV) cell onto the printed circuit structure such that a terminal of the PV cell is electrically connected to at least one of the first and second conductors of the printed circuit structure; and

laminating the printed circuit structure onto the optical element such that the (PV) cell is disposed at the focal point.