Application of decorative films to photovoltaic arrays (pv arrays)

Abstract

The invention relates to a photovoltaic module (4) having a colored decorative film (2) which covers the optically active upper face of the photovoltaic module, wherein the decorative film is formed by a plastic film containing one or more coloring agents, preferably pigments, and the decorative film has an average transmittance of at least 50% in the wavelength range of 750-1150 nm.

Description

[0001] 202301935

[0002] 1

[0003] Description

[0004] Application of decorative films on photovoltaic systems (PV systems)

[0005] The invention relates to a photovoltaic module with a colored decorative film that covers the optically active top side of the photovoltaic module.

[0006] To convert solar energy into electrical energy, photovoltaic modules, hereinafter also referred to as PV modules, generally use radiation in the wavelength range between 400 and 1150 nm, with the highest yield usually being achieved in the range between 600 and 900 nm.

[0007] In recent years, photovoltaic technology has become increasingly affordable thanks to improvements in energy conversion efficiency, reduced manufacturing costs, and government incentive programs. However, the appearance of photovoltaic modules has not changed significantly since their inception. The vast majority of modules are generally black or dark blue and are not particularly attractive.

[0008] Because of their visual appearance, PV modules are therefore not usually used on facades or other prominently visible surfaces, which limits the application areas of PV modules.

[0009] US 11161369 B2 describes graphic layers for displaying a visible representation of an image along the surface of a photovoltaic module, comprising a multitude of opaque, isolated areas and at least one transparent, contiguous area. With this solution, the potential energy yield depends on the proportion of transparent areas. If this proportion is small, the energy yield is drastically reduced; if it is too large, the module becomes visible, thus impairing its appearance. 202301935

[0010] 2

[0011] There is no inexpensive PV module available that is both visually appealing and does not reduce the light absorption of PV modules to such an extent that their operation becomes economically unviable.

[0012] The object of the present invention is to overcome the disadvantages of the prior art described above. In particular, the object of the invention was to provide a PV module that has an aesthetically pleasing appearance and at the same time does not excessively reduce the energy yield of the PV module, so that economical operation of the PV module remains possible.

[0013] It was found that this could be solved by covering the photovoltaic module with a colored decorative film that has sufficient transparency in the wavelength range from 750 nm upwards.

[0014] The invention thus relates to a PV module with a colored decorative film covering the optically active top surface of the PV module, wherein the decorative film is formed from a plastic film containing one or more coloring agents, preferably pigments, and the decorative film has an average transmittance of at least 50% in the wavelength range of 750 to 1150 nm.

[0015] The PV module according to the invention, which is provided with the colored decorative film, is visually appealing and thus enables the use of the PV modules, e.g., on facades or other prominently visible surfaces, without impairing the visual appearance of these surfaces. Nevertheless, a sufficient energy yield can be achieved with the PV module according to the invention. The result is a PV module that is visually appealing and can be operated economically.

[0016] The invention is explained in detail below.

[0017] In the following, radiation in the visible (VIS) and infrared (IR) ranges will be referred to as light. Visible light lies in the 202301935

[0018] 3

[0019] Wavelength range from approximately 380 nm to 780 nm. Light in the IR range lies within the

[0020] Wavelength range from approximately 780 nm to 1 mm.

[0021] The PV module according to the invention with a colored decorative film is covered on the optically active top side of the PV module with a colored decorative film.

[0022] A photovoltaic (PV) module, also called a solar module or solar panel, converts sunlight into electrical energy using its integrated solar cells. PV modules generally use light in the wavelength range between 400 and 1150 nm to convert sunlight into electrical energy, with the highest efficiency occurring in the range between 600 and 900 nm.

[0023] A photovoltaic (PV) module comprises one or more solar cells. The solar cells can be rigid or flexible. They are usually encapsulated in a plastic layer, particularly a transparent one. A PV module, especially one with rigid solar cells, typically also has a glass pane on the top side of the one or more solar cells or encapsulated solar cells, which serves, for example, to protect against hail or dirt. The top side is understood to be the side of the PV module facing sunlight.

[0024] On the back of one or more solar cells, there is usually a plastic film or another glass pane. Other components of the PV module typically include electrical circuits and connections for conducting the generated electrical current. The circuits can be series or parallel. Most PV modules also have a frame element for transport, stiffening, and mounting. However, there are also frameless PV modules that can be installed in suitable substructures. PV modules with one or more flexible solar cells generally do not have rigid components such as glass panes or frame elements. 202301935

[0025] 4

[0026] The optically active top surface of the PV module is the side where incident light is converted into electrical energy by the solar cells. It goes without saying that this optically active top surface faces the sun when the PV module is operating.

[0027] The optically active top surface of the PV module according to the invention is covered by the colored decorative film. This covering prevents most of the sunlight from directly reaching the optically active top surface of the PV module, instead diverting it first to the colored decorative film. The portion of the sunlight that passes through the colored decorative film then reaches the optically active top surface of the PV module.

[0028] The colored decorative film, which covers the optically active top surface of the PV module according to the invention, thus acts as a privacy screen for the optically active top surface.

[0029] A decorative film serves decorative purposes, e.g., to make the appearance of surfaces more visually appealing. The colored decorative film used according to the invention is, in particular, a fully colored decorative film. The colored decorative film is typically a single-color decorative film.

[0030] The colored decorative film can be any color and selected according to the desired look. For example, the colored decorative film can be blue, cyan, magenta, red, yellow, green, black, white, or gray, or a color formed from a mixture of two or more of these colors.

[0031] The colored decorative film is made of a plastic film containing one or more coloring agents, preferably pigments. The coloring agent(s), in particular pigments, give the decorative film its color.

[0032] Any suitable coloring agent can be used, e.g., pigments and dyes, where one or more pigments 202301935

[0033] 5 are preferred. The coloring agents can be organic or inorganic, in particular pigments. The use of one or more organic pigments is particularly preferred.

[0034] Particularly suitable are coloring agents, especially pigments, which have high IR transparency (50% average transmission between 700 and 1000 nm).

[0035] Examples of suitable organic pigments are isoindoline pigments, phthalo pigments, especially phthalocyanine pigments, azo pigments and / or perylene pigments.

[0036] The colored decorative film is made from a plastic film containing one or more coloring agents. To manufacture it, these coloring agents are mixed into the base plastic material. The colored decorative film is then produced from this base plastic material containing the coloring agent(s) using standard manufacturing methods. In addition to the plastic and coloring agents, the base plastic material may contain other additives commonly used in this field.

[0037] The plastic film is preferably made of a predominantly, e.g., at least 65%, or completely amorphous plastic. The plastic film is preferably made of polyethylene terephthalate, polymethyl methacrylate, polyvinyl chloride (PVC), or polypropylene. A PVC film is particularly preferred.

[0038] Preferably, the plastic film is IR-transparent. Particularly preferred is a plastic film that is both IR-transparent and transparent in the visible (VIS) range. This refers to the plastic film that forms the colored decorative film but does not contain the coloring agents. 202301935

[0039] 6

[0040] An IR-transparent plastic film is understood to be, in particular, a plastic film that has an average transmission of 50% between 700 and 1000 nm.

[0041] The content of one or more coloring agents, preferably pigments, in particular organic pigments, in the colored decorative film is, for example, in the range of 0.5 wt.% to 10 wt.%, preferably 2 wt.% to 8 wt.%, based on the total weight of the colored decorative film.

[0042] The colored decorative foil has, for example, a thickness of 30 to 300 pm, preferably 70 to 180 pm, more preferably 80 to 120 pm.

[0043] Decorative films of this thickness have the advantage that they are mechanically stable enough and at the same time have sufficient transmittance for the relevant wavelength ranges, which decreases with increasing thickness of the decorative film.

[0044] The colored decorative film used according to the invention has an average transmittance of at least 50% in the wavelength range of 750 to 1150 nm.

[0045] Transmission defines the permeability of a medium to electromagnetic radiation, or light. The transmittance of a medium is the ratio of transmitted radiant flux to incident radiant flux and is expressed as a fraction or as a percentage. Transmittance depends on the wavelength of the light. Average transmittance defines the average transmittance within a specific wavelength range. Transmittance can be determined, for example, according to ISO 9050:2003 for a specific wavelength range.

[0046] Preferably, the colored decorative film has an average transmittance of at least 60%, preferably at least 70%, in the wavelength range of 750 to 1150 nm. 202301935

[0047] 7

[0048] In preferred embodiments, the colored decorative film is applied directly to the PV module or to a glass pane or plastic plate positioned between the decorative film and the PV module.

[0049] The glass panes and additional glass panes can be made of, for example, tempered safety glass (ESG). The plastic sheet can be made of the same plastics as described for the top film. It is understood that the glass panes, additional glass panes, and plastic sheets should be transparent, especially in the visible (VIS) range, but usually also in the infrared (IR) range.

[0050] The application of the colored decorative film to the PV module or a glass pane or plastic sheet can be carried out in all usual ways, with the colored decorative film preferably being applied by lamination.

[0051] The following describes different variations for the use of the decorative film according to the invention, illustrating the high flexibility of its application. Therefore, various variations can be implemented depending on the suitability of the building structure.

[0052] In one embodiment, the PV module has one or more flexible solar cells, and the colored decorative film is applied directly to the PV module. With this embodiment, a flexible PV module with the colored decorative film can be obtained. This allows for easy mounting of the PV module onto the designated surfaces for operation, which can also be curved surfaces.

[0053] In an alternative embodiment, the PV module comprises one or more rigid solar cells and a glass pane over the solar cell(s), wherein the colored decorative film is applied directly to the glass pane of the PV module. This embodiment is particularly suitable if, during assembly of the PV module, the glass pane positioned on top of the solar cell is provided with the colored decorative film before positioning, e.g., by lamination. 202301935

[0054] 8

[0055] In another alternative embodiment, the PV module has one or more rigid solar cells and a glass pane over the solar cell(s), and the colored decorative film is applied to an additional glass pane or plastic sheet, e.g. by lamination, wherein the additional glass pane or plastic sheet is preferably positioned between the decorative film and the glass pane of the PV module.

[0056] The additional glass pane or plastic panel, covered with colored decorative film, can be positioned directly on top of or spaced apart from the glass pane of the PV module. In a spaced-apart arrangement, the additional glass pane or plastic panel is placed in front of the PV module.

[0057] If the additional glass pane or plastic plate is placed directly on the glass pane of the PV module, this can be done in the usual way, e.g. by gluing the two glass panes or the glass pane and the additional plastic plate together or by connecting them using one or more fasteners, e.g. clamps.

[0058] Applying the colored decorative film to an additional pane of glass or plastic sheet has the advantage that the film does not need to be applied directly to the PV module. This is particularly beneficial when the PV module is already installed and needs to be retrofitted. Applying the colored decorative film to an additional pane of glass is then much simpler from an installation standpoint.

[0059] If the additional glass pane or plastic panel covered with the colored decorative film is positioned at a distance from the glass pane or plastic panel of the PV module, a gap is formed between the PV module and the additional glass pane or plastic panel. The distance between the PV module and the additional glass pane or plastic panel can be, for example, in the range of 1 to 15 cm, preferably 2 to 8 cm. The spaced arrangement can be achieved, for example, using spacers. 202301935

[0060] 9

[0061] The spacing between the separate glass or plastic sheet and the glass pane of the PV module offers the advantage of easy replacement or removal of the decorative film, for example, for repairs or to change the appearance. Furthermore, this spacing allows air to circulate through the gap and thus cool the PV module.

[0062] In one embodiment, the colored decorative film is printed with the PV module. More recently, PV modules have been developed that can be manufactured by printing. Such printable PV modules are suitable for printing onto the colored decorative film.

[0063] In one embodiment, the colored decorative film or a top film arranged above it can be printed, in particular with a color print. The printing inks can be selected so that the transmittance of the decorative film is not affected. The print could, for example, be the imprinting of characters or graphic elements. In this way, a specific design, instructions, or advertising can be placed on the decorative film.

[0064] In a preferred embodiment, a top film can be arranged on the colored decorative film, wherein the top film is a plastic film, preferably a plastic film made of polyethylene terephthalate, polymethyl methacrylate, polyvinyl chloride, polypropylene or polymethyl methacrylate (PMMA). A PMMA film is particularly preferred as the top film.

[0065] The top film can be applied to the colored decorative film in the usual way, e.g., by lamination. The top film serves as a protective layer. Applying the top film improves, for example, the weather resistance and protection of the PV module according to the invention with the colored decorative film. 202301935

[0066] 10

[0067] Preferably, the top film is IR-transparent. Particularly preferably, the plastic film is IR-transparent and transparent in the visible (VIS) range.

[0068] Furthermore, the invention relates to the use of a colored decorative film for covering the optically active top surface of a photovoltaic module, wherein the decorative film is formed from a plastic film containing one or more coloring agents, preferably pigments, and the decorative film has an average transmittance of at least 50% in the wavelength range of 750 to 1150 nm.

[0069] All the above information regarding the colored decorative film and the photovoltaic module according to the invention, as well as their arrangements to each other, naturally also applies accordingly to the use of the colored decorative film according to the invention for covering the optically active top surface of a PV module.

[0070] The use according to the invention is particularly suitable for photovoltaic modules that are mounted on prominent, visible surfaces. Such surfaces on which photovoltaic modules are mounted include, for example, a noise barrier, a facade, a vehicle, a bus, or a train. In the case of vehicles, buses, or trains, the outer surfaces are particularly suitable, preferably the outer side walls.

[0071] The color of the decorative film can be adapted to the appearance of the surface to which the PV module according to the invention is attached. For example, the color of the decorative film can match the color of the surface, so that the appearance of the PV module blends in with that of the surrounding surface, making the PV module hardly visible.

[0072] The invention is explained in more detail below with reference to exemplary embodiments and drawings, which, however, are in no way intended to be considered limiting. The drawings show: 202301935

[0073] 11

[0074] Fig. 1 shows a cross-sectional view of a section of a PV module according to the invention.

[0075] Fig. 2 shows a cross-sectional view of a further section of a PV module according to the invention,

[0076] Fig. 3 shows a cross-sectional view of a further section of a PV module according to the invention.

[0077] Fig. 4 shows a schematic diagram illustrating the functionality of the PV module according to the invention.

[0078] Figure 1 schematically shows a cross-section of a PV module according to the invention with a colored decorative film. The PV module 4 comprises one or more rigid solar cells encapsulated with a protective layer and a glass pane arranged over the solar cell(s) (details of the PV module are not shown). The colored decorative film 2 is arranged, laminated, or bonded to an additional glass pane 3. A transparent top film 1, such as a colored PMMA film 1, is arranged or laminated to the colored decorative film 2. The additional glass pane 3, which is provided with the colored decorative film 2 and the top film 1, is arranged or bonded directly to the PV module 4. The colored decorative film 2 is, for example, a PVC film colored by incorporating one or more organic pigments.

[0079] Figure 2 schematically shows a cross-section of a PV module according to the invention with a colored decorative film. The PV module 4 comprises one or more rigid solar cells encapsulated with a protective layer and a glass pane arranged over the solar cell(s) (details of the PV module are not shown). The colored decorative film 2 is arranged or laminated onto an additional glass pane 3. The colored decorative film 2 is, for example, a PVC film colored by incorporating one or more organic pigments. A transparent top film 1, such as a PMMA film 1, is arranged or laminated onto the colored decorative film 2. The additional glass pane 3, which is provided with the colored decorative film 2 and the top film, is arranged at a distance above the PV module 4. The spaced arrangement can be achieved, for example, by means of 202301935

[0080] 12

[0081] This is achieved using spacers (not shown) positioned between the PV module and the additional glass pane. The distance between the PV module and the additional glass pane can be, for example, approximately 5 cm.

[0082] Figure 3 schematically shows a cross-section of a PV module 5 according to the invention with a colored decorative film 2. A colored decorative film 2 is arranged directly on a flexible PV module 5. A PMMA top film 1 is arranged on the colored decorative film 2. The colored decorative film 2 is preferably a PVC film colored by incorporating one or more pigments.

[0083] Figure 4 shows a schematic diagram illustrating the functionality of the PV module according to the invention, based on the arrangement shown in Figure 2. The complete light spectrum of the sun encompasses wavelengths from 0.1 nm in the X-ray range to 10,000 nm in the radio wave range. For solar applications, wavelengths from 400 to 1150 nm are particularly important. In the range of 400 to 1150 nm, the light is partially absorbed and partially transmitted by the colored decorative film 2. The transmitted light can be used by the solar cell in a PV module to generate electrical current.

[0084] 202301935

[0085] 13

[0086] Reference symbol list

[0087] 1 top film, e.g. PMMA top film

[0088] 2 colored decorative film, e.g. colored PVC decorative film; 3 additional glass panes

[0089] 4 rigid PV modules

[0090] 5 flexible PV modules

Claims

202301935 14 Patent claims 1. Photovoltaic module with a colored decorative film covering the optically active top surface of the photovoltaic module, wherein the decorative film is formed from a plastic film containing one or more coloring agents, preferably pigments, and the decorative film is optically active in the wavelength range from 750 to 1150 nm has an average transmittance of at least 50%.

2. Photovoltaic module according to claim 1, wherein the decorative film has an average transmittance of at least 60%, preferably at least 70%, in the wavelength range of 750 to 1150 nm, and / or the colored decorative film has a transmittance of at least 25% at 800 nm.

3. Photovoltaic module according to one of the preceding claims, wherein the plastic film is IR-transparent or the plastic film is IR-transparent and transparent in the visible wavelength range.

4. Photovoltaic module according to one of the preceding claims, wherein the plastic film is a plastic film made of polyethylene terephthalate, polymethyl methacrylate, polyvinyl chloride or polypropylene, preferably polyvinyl chloride.

5. Photovoltaic module according to one of the preceding claims, wherein the content of one or more coloring agents, preferably pigments, in the colored decorative film is in the range of 0.5 wt.% to 10 wt.%, preferably 2% to 8% by weight, based on the total weight of the colored decorative foil.

6. Photovoltaic module according to one of the preceding claims, wherein the one or more coloring agents are one or more organic pigments. 202301935 15 7. Photovoltaic module according to one of the preceding claims, wherein the colored decorative film has a thickness of 30 to 300 pm, preferably 70 to 180 pm, more preferably 80 to 120 pm.

8. Photovoltaic module according to one of the preceding claims, wherein the colored decorative film is applied directly to the photovoltaic module or to a glass pane or plastic plate which is positioned between the decorative film and the photovoltaic module.

9. Photovoltaic module according to one of the preceding claims, wherein a) the photovoltaic module comprises one or more flexible solar cells and the colored decorative film is applied directly to the photovoltaic module, b) the photovoltaic module comprises one or more rigid solar cells and a glass pane over the solar cell(s) and the colored decorative film is applied directly to the glass pane, or c) the photovoltaic module comprises one or more rigid solar cells and a glass pane over the solar cell(s) and the colored decorative film is arranged on an additional glass pane or plastic plate, wherein the additional glass pane or plastic plate is preferably positioned between the decorative film and the glass pane or plastic plate of the photovoltaic module, wherein the additional glass pane is arranged directly on or spaced apart from the glass pane of the photovoltaic module.

10. Photovoltaic module according to one of the preceding claims, wherein the colored decorative film is printed with the photovoltaic module and / or wherein a print, in particular a color print, is applied to the colored decorative film.

11. Photovoltaic module according to one of the preceding claims, wherein a further plastic film is arranged as a top film on the colored decorative film, wherein the further plastic film is preferably made of polyethylene terephthalate, polymethyl methacrylate, polyvinyl chloride or polypropylene, preferably polymethyl methacrylate. 202301935 16 12. Use of a colored decorative film for covering the optically active top surface of a photovoltaic module, wherein the decorative film is formed from a plastic film containing one or more coloring agents, preferably pigments, and the decorative film has an average transmittance of at least 50% in the wavelength range of 750 to 1150 nm, wherein the colored decorative film is preferably defined as in any one of claims 2 to 11.

13. Use according to claim 12, wherein the photovoltaic module is attached to a noise barrier, a facade, a vehicle, a bus or a train.

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