PHOTOVOLTAIC MODULE WITH INTEGRATED LIGHT-DIRECTING STRUCTURE ON THE BASIS OF TOTAL INTERNAL REFLECTION

Abstract

In a photovoltaic module (1) comprising a plurality of electrically interconnected solar cells (2) embedded in an encapsulation film(5) at least on one side and arranged at a distance from one another, and, if appropriate, a rear-side film (6) and a light-transmissive cover plate, light-guiding films forming prism-like structures (4) are integrated in regions of the photovoltaic module (1) that are free of solar cells (2) and the prism-like structures (4) and complementary air and gas pockets (8) are arranged alternately. The prism-like structures (4) of the light-guiding films are arranged in such a way that light impinging on the light-guiding, prism-like structures (4) is guided in the direction of the solar cells (2). An encapsulation film (5) is arranged on both sides of the solar cell and the light-guiding film forming prism-like structures (4) is arranged within the encapsulation film (5), and the light-guiding films forming prism-like structures (4) are covered, if appropriate, by a transparent polymer film (6, 12).

Claims

1-13. (canceled)

14. A photovoltaic module (1) comprising: a plurality of electrically connected solar cells (2) arranged spaced apart from one another and embedded on both sides in an encapsulation film (5); and a light-permeable cover plate, wherein integrated in areas of the photovoltaic module (1) that are free of solar cells (2), are films embodying light-directing, prism-like structures (4), wherein the prism-like structures (4) of the light-directing films are arranged such that light incident on the light-directing prism-like structures (4) is directed toward the solar cells (2), wherein the prism-like structures (4) and complementary air and gas inclusions (8) are arranged alternating, and wherein the photovoltaic module (1) comprises a back-side film (6) that is embodied integrally with the films embodying the light-directing, prism-like structures (4).

15. The photovoltaic module (1) of claim 14, wherein the films with prism-like structures (4) are added in the area between the solar cells (2) that is free of solar cells.

16. The photovoltaic module (1) of claim 14, wherein the prism-like structures (4) are embodied as oblique structures similar to a triangular prisms having an essentially right angle.

17. The photovoltaic module (1) of claim 16, wherein a surface of the prism-like structure (4) opposing the essentially right angle is embodied as a surface having a flat surface, a convex curvature, a concave curvature, or a convex/concave curvature.

18. The photovoltaic module (1) of claim 14, wherein a flank angle of the prism-like structure is selected between 25° and 65° and a preventative flank angle of the prism-like structure is selected between 80° and 90°.

19. The photovoltaic module (1) of claim 14, wherein the prism-like structures (4) are embodied having a height between 100 nm and 100 mm, especially 10 μm to 300 μm.

20. The photovoltaic module (1) of claim 14, wherein the encapsulation film (5) is arranged on both sides of the solar cells (2) and optionally the film embodying the light-directing, prism-like structures (4) is arranged in the interior of the encapsulation film (5).

21. The photovoltaic module (1) of claim 14, wherein the back-side film (6) has the light-directing, prism-like structures (4) integrated on its side facing the solar cells (2).

22. The photovoltaic module (1) of claim 14, wherein the film embodying the light-directing, prism-like structures (4) and the polymer film sealing these structures (4) are embodied from the same material, selected from polyethylene terephthalate (PET), polyurethane (PU), polyethylene (PE), polyurethane acrylate (PUA), polyamide, polytetrafluorethylene (PTFE), polystyrene (PS), polycarbonate (PC), polyethylene naphthalate (PEN), polymethyl methacrylate (PMMA), or silicone.

23. The photovoltaic module (1) of claim 14, wherein a transparent polymer film in the range between 300 nm and 2500 nm, in particular 350 nm to 1200 nm, made of a material selected from ethylene vinylacetate (EVA), polyvinylbutyral (PVB), silicone, or polyethylene (PE), is used as the encapsulation film.

24. The photovoltaic module (1) of claim 14, wherein a plate made of low-iron glass having a thickness between 1 nm and 60 mm is used as the cover plate (7).

25. The photovoltaic module (1) of claim 14, wherein an electrical insulation film, especially an insulation film having a coefficient of reflectivity of R>90% in a wavelength range of 350 nm to 1200 nm, is used as the back-side film (6).

26. The photovoltaic module (1) of claim 14, wherein the encapsulation film (5) is embodied as a reflective barrier layer, especially an electrical insulation film.

27. The photovoltaic module (1) of claim 14, wherein the film embodying the encapsulation film (5), the back-side film (6), and the light-directing prism-like structures (4) are embodied as reflective, electrical insulation films that reflect more than 90% of the light in a wavelength range between 350 nm and 1200 nm.

28. The photovoltaic module (1) of claim 14, wherein the back-side film (6) is embodied as a glass plate (7).

Description

[0023] The invention shall be described in greater detail in the following using exemplary embodiments depicted in the drawings.

[0024] FIG. 1 depicts a structure of a photovoltaic module according to the invention;

[0025] FIG. 2 depicts one option for arranging the elements embodying the photovoltaic module;

[0026] FIG. 3 depicts one option for arranging the elements embodying the photovoltaic module;

[0027] FIG. 4 depicts another option for arranging the elements embodying the photovoltaic module;

[0028] FIG. 5 is a schematic depiction of light-directing, prism-like structures according to the invention;

[0029] FIG. 6 depicts three additional possible forms of the light-directing, prism-like structures that may be used in a photovoltaic module according to the invention; and,

[0030] FIG. 7 depicts the outer left edge area of the photovoltaic module from FIG. 1, in which, in addition to the layer structure, the path of an incident light beam is illustrated.

[0031] FIG. 1 illustrates a photovoltaic module 1 according to the invention in detail. Two solar cells 2 that are arranged spaced apart from one another are depicted schematically in this photovoltaic module 1. In the embodiment of the photovoltaic module 1 according to FIG. 1 it may be seen that an edge area 3 of the photovoltaic module 1 does not contain any solar cells 2 and this edge area 3 cannot contribute to converting sunlight to energy. In order to convert as much sunlight striking this edge area 3 to energy as possible, in the depiction of FIG. 1 a plurality of light-directing structures 4 that have the shape of oblique prisms are provided in both edge areas 3 of the photovoltaic module 1. When light strikes these essentially prism-like structures 4 of the light directing elements perpendicularly, it is reflected internally totally toward an interior of the photovoltaic module 1, refracted on one of the adjacent prisms, and then finally totally reflected on the interface of the glass plate 7, functioning as cover plate, with the ambient air, so that this light is available for a further conversion to energy, and is not unavailable for conversion to energy like photovoltaic modules according to the prior art. In order to protect the solar cells 2 of the photovoltaic module 1 according to FIG. 1 from any destruction, as may be seen from FIG. 1 they are embedded in an encapsulation film 5. To complete the photovoltaic module 1, the latter is further held by a back-side plate 6 and covered with a glass plate 7. Finally, air 8 is added between the plurality of oblique prisms 8 in order to make it possible to direct light without providing a reflective coating.

[0032] The back-side plate or back-side film 6 is an electrical insulation film that has a relatively high coefficient of reflectivity for sunlight in order to reflect sunlight that has penetrated to the back-side plate 6 and have it available for further conversion to energy in the interior of the photovoltaic module 1.

[0033] The depiction according to FIG. 2, in which the reference numbers from FIG. 1 are essentially retained, illustrates one option for how a photovoltaic module 1 according to the invention may be constructed or produced.

[0034] First an encapsulation film 5 is applied to the entire surface of a glass plate 7, and in a next step the photovoltaic module 1 and the films with prism-like structures 4 are applied to said encapsulation film 5. As may clearly be seen in FIG. 2, the films with the prism-like structures 4 are applied in those areas of the photovoltaic module that are not covered with solar cells 2 and are oriented toward the plate 7, and a step, and a step according to which the prism-like structures 4 are covered by a protective film 12. In a further step, a further encapsulation film 5 and a back-side film 6 are applied to this layer 12. It is obvious that in order to attain a photovoltaic module as is depicted in FIG. 1, it is merely necessary to add a film with prism-like structures 4 in the area between the solar cells 2, which area is free of solar cells. In particular, the prism film 4 is enclosed with the encapsulation film 5 without the optical effect being destroyed, because in the required lamination process the encapsulation material, i.e. the film 5, cannot penetrate between the plate 6 and the structures 8 released by the prism film 4, because the prism structure 8 is protected by the film 12. For this reason it is possible to embody light-directing structures even in the interior of the module.

[0035] The back-side plate 6 may be embodied as a plate-like element or film-like element, both in the depiction according to FIG. 1 and that according to FIG. 2, wherein the back-side film may also be embodied integrally with the film having the prism-like structures 4 or may have the prism-like structures immediately on its side facing the solar cells 2.

[0036] FIG. 3 illustrates another option for constructing or producing a photovoltaic module according to the present invention.

[0037] In this depiction, as well, in a first step an encapsulation film 5 is applied to a glass plate 7, and in another step the solar cells 2 are applied to the encapsulation film 5 and then are covered by an encapsulation film 5. In the next step, the film with prism-like structures 4 is applied in those areas that are not covered by solar cells 2, wherein when this production method is used the protective film 12, which is absolutely necessary in the structure in FIG. 2 for protecting the prism-like structures, may be omitted. Then the photovoltaic module 1 is again covered using a back-side film or back-side plate.

[0038] In the depiction according to FIG. 4, the structure is essentially the same as that in FIG. 3, with the exception that after the second encapsulation film 5 is applied, the back-side film 6 is applied, on which back-side film 6 the prism-like structures 4 are already embodied, so that one work step may be saved.

[0039] In all of the embodiments according to the invention, the prism-like structures 4 are between 100 nm and 100 mm in height, wherein in the most common areas of application they are 10 μm to 300 μm in height.

[0040] The depiction in FIG. 5 illustrates one embodiment of the light-directing, prism-like structures 4, and it may be seen from them that these structures 4 essentially have the shape of an oblique prism, with an essentially right angle that corresponds to the preventative flank angle and that is normally between 80° and 90°. Consequently, in the same way the flank angle is selected to be between 25° and 65° , and the flank 9 facing the light is essentially oriented such that light perpendicularly incident on it is reflected toward the center.

[0041] FIG. 6 illustrates different shapes of the light-permeable, prism-like structures 4, wherein 6a depicts a structure that has a concavely curved flank with which light is reflected toward the center of a photovoltaic module 1. FIG. 6b illustrates a different embodiment of the light-permeable, prism-like structures 4, in which structures the flank 9 of the prism facing the light has one convex and one concave curvature, wherein the concave curvature is provided in the area of the base of the cylinder. Finally, FIG. 6c illustrates an embodiment of the light-permeable, prism-like structures 4 that have a concavely/convexly curved flank 9 and that also reflect light toward a center of a photovoltaic module 1.

[0042] FIG. 7, in which the reference numbers from FIG. 1 are retained, also depicts the path of a light beam 10 perpendicularly striking the photovoltaic module 1. The perpendicularly incident light beam is reflected at the interface of the structured film 4 with the air inclusion 8 embodied like a prism and directed one or a plurality of adjacent prisms, where the light beam is directed using refraction, especially when it strikes an inclined surface of one of the adjacent prisms 11, toward the glass plate 7, where the light is again reflected by total reflection toward the interior of the photovoltaic module 1 and strikes a solar cell 2 and is thus available to be converted to energy.