Colored solar cells comprising effect pigments

Abstract

The present invention relates to a colored solar cell or a colored solar cell module comprising two or more transparent front cover layers, each transparent front cover layer comprising effect pigments of a different color, and to a method for preparing the same.

Description

[0001] The invention relates to a colored solar cell or a colored solar cell module, which comprises two or more transparent front cover layers, each transparent front cover layer containing effect pigments of different colors, and to a method for producing the same.

[0002] Solar cells have shown tremendous success over the past few years and in 2019 have exceeded 600GW of global grid-connected installations, most of which are installed on a utility scale. The basic function of all solar cells relies on photoactive materials that absorb light and generate excited electron-hole pairs. The electron-hole pairs are separated within the solar cell by a region with different mobilities for electrons and holes, the so-called pn junction. Due to the different kinds of light-absorbing materials that can be used, different kinds of solar cell technologies are known in the solar industry:

[0003] 1) Crystalline silicon solar cells (single crystal c-Si and multi-crystalline mc-Si)

[0004] 2) Cadmium telluride solar cells (CdTe)

[0005] 3) Copper-Indium-Gallium-Diselenide (CIGS / CIS)

[0006] 4) Amorphous silicon solar cells (a-Si)

[0007] 5) III / V solar cells, such as gallium arsenide (GaAs) solar cells, or multi-junction solar cells consisting of stacks of group III and group V elements such as germanium / indium-(aluminum)-gallium-arsenide or phosphide (In(Al)GaAs / P)

[0008] 6) Dye-sensitized solar cells (DSSC)

[0009] 7) Organic Solar Cells (OSC)

[0010] 8) Perovskite Solar Cells (PSC)

[0011] 9) Quantum dot solar cells (QSC)

[0012] 10) Other II / VI solar cells composed of Group II and Group VI elements such as zinc selenide (ZnSe) or ferrous sulfide (FeS)

[0013] 11) Tandem solar cells

[0014] However, using more surfaces such as buildings and other surfaces on objects (e.g., cars) increases the total surface area available for solar energy production. To this end, new technologies and methods for preparing solar cells with attractive colors and hues and improving efficiency at different angles of incidence are of major interest to the solar energy industry.

[0015] For example, by using a rear encapsulation film of the same color as the solar cells and tinting the conductive parts of the solar module / panel, a good color impression can be achieved. However, for each installation in a building, the market or the building owner may require a custom color. This makes tinting complicated and expensive.

[0016] WO 2019 / 122079A1 discloses a colored solar cell or solar cell module including a layer containing a translucent effect pigment. The translucent effect pigment controls the color of the light incident surface side without compromising the efficiency of the solar panel. The effect pigment reflects a portion of the visible sunlight, but allows the light required to generate energy to pass. Since the effect pigment is in the shape of a small piece, the more pigment flakes are oriented so that their edges face the visual surface of the solar module, the lower their color reflection will be. Therefore, the effect pigment should preferably be mainly oriented substantially parallel to the module surface, while in order to maintain the color impression related to the visual angle, a specific random orientation is still desirable to a certain extent. The color can be achieved by using a single pigment or a mixture of pigments, such as a glass color applied and cured on the front glass, or, for example, by extruding a single pigment or a mixture of pigments into an encapsulating polymer film and using the colored polymer film as a front encapsulation in a solar module or device.

[0017] For customized colors, glass colors can be efficiently mixed and applied for small batches. However, additional printing and curing steps are required, which is a cost disadvantage. In addition, when pigment mixtures are used in the large-scale manufacturing process of colored solar cells, the color may vary slightly from batch to batch, making it difficult to reproduce the same color for modules covering a large area.

[0018] It is therefore an object of the present invention to provide an improved method for the tinting of solar cells and solar cell modules which does not have the disadvantages observed in the prior art methods, which does enable the tinting of solar cells in a wide range of customized colors, provides solar cell modules with a uniform color appearance even over large areas, and is suitable for a time- and cost-effective large-scale production process.

[0019] Another object of the present invention is to provide improved tinted solar cells and solar cell modules having uniform color appearance over a wide range of custom colors. Another object of the present invention is to provide a method that can increase the flexibility of creating custom colors and using tinted encapsulation films for solar cells and solar cell modules. Other objects of the present invention will be apparent to those skilled in the art through the following description and examples.

[0020] Surprisingly, it has been found that one or more of these objects can be achieved by the tinted solar cells and solar cell modules disclosed and claimed below, which comprise two or more different transparent front cover layers, wherein each transparent front cover layer (hereinafter also referred to as "TFCL") contains effect pigments of different colors.

[0021] The present application relates to a tinted solar cell or solar cell module comprising two or more TFCLs, each of said TFCLs containing at least one, preferably only one, effect pigment having a specific color, consisting of a transparent or translucent flake-like substrate coated with one or more layers of transparent or translucent material and an optional back coating, and wherein at least one TFCL contains an effect pigment of a different color than the effect pigments contained in the other layers of the other transparent front covers.

[0022] Preferably, the TFCL is an encapsulation layer or film or a component thereof, or together forms a front encapsulation film or a component thereof.

[0023] The present application also relates to a method for preparing a tinted solar cell or a tinted solar cell module, comprising the step of laminating two or more TFCLs onto the front side of the solar cell or solar cell module, each TFCL containing an effect pigment as described above and below having a specific color, wherein at least one TFCL contains an effect pigment of a different color from the effect pigments contained in the other TFCLs.

[0024] The present invention also relates to the use of tinted solar cells and tinted solar cell modules as described above and below in architectural devices or equipment preferably selected from windows, doors, building facades, building roofs or floors, walls, structural glass, curtain walls, exhibition halls, car roofs, car bodies, mobile phones, handheld PCs (such as tablets), plug-in solar modules, roof tiles, solar panels, photovoltaic (PV) fences, military equipment, radios, radio equipment, music boxes, mobile power banks, watches, glasses and goggles.

[0025] The present invention also relates to a building device or equipment comprising one or more tinted solar cells or tinted solar cell modules as described above and below, the device or equipment is preferably selected from windows, doors, building facades, building roofs or floors, walls, structural glass, curtain walls, exhibition halls, car roofs, car bodies, mobile phones, handheld PCs (such as tablets), plug-in solar modules, roof tiles, solar panels, PV fences, military equipment, radios, radio equipment, music boxes, mobile power banks, watches, glasses and goggles.

[0026] In this context, the term "front side" of a solar cell or solar cell module refers to the light receiving side or the side facing the incident light, while the term "rear side" or "back side" of a solar cell or solar cell module refers to the side opposite to the radiation receiving side or facing away from the incident light. The term "front cover layer" or "front encapsulation film" refers to a layer, sheet or encapsulation film disposed on the front side of a solar cell or solar cell module. The terms "rear glass / sheet" and "rear encapsulation film" refer to a glass, sheet or encapsulation film disposed on the rear side of a solar cell or solar cell module.

[0027] In this context, unless otherwise specified, the term "solar cell" should be understood to include a single solar cell and a solar cell module, as well as arrays, strings or patterns thereof. Likewise, unless otherwise specified, the term "solar cell module" is also understood to include a single solar cell.

[0028] Above and below, unless stated otherwise, the weight percentages of light-scattering particles and effect pigments are based on the total weight of the solids part of the layer, sheet or film.

[0029] Above and below, a layer, sheet or film according to the invention is also referred to as "layer" for short, which is understood to include the layer, sheet or film according to the invention as described above and below.

[0030] Figure 1 A colored solar cell module according to the invention is shown by way of example and schematically.

[0031] The present invention provides an efficient method for coloring prior art solar cells or solar cell modules made of a plurality of electrically interconnected solar cells, which method has great flexibility and achieves a wide range of different colors with low or negligible loss of solar cell efficiency and with a high level of long-term stability. In addition, the present invention provides a solution to achieve a wide range of customized colors with good batch-to-batch reproducibility and suitable for a wide range of applications.

[0032] Thus, it was surprisingly found that by applying two or more individual TFCLs as stacked films during the lamination process of a solar module, for example as front encapsulation, wherein each of said layers contains effect pigments of a different single color, a wide range of customized colors can be created.

[0033] For example, when using a stack of two or more red / green / blue encapsulating polymer films laminated on a solar cell, it was surprisingly found that a uniform grey color can be achieved after lamination, which displays a color appearance similar to that of a single encapsulating polymer film containing a corresponding mixture of red / green / blue pigments that has been added to the polymer melt and extruded together with the polymer film. However, encapsulating films containing only one colored effect pigment with a constant color appearance are easier to reproduce in large quantities than films containing a mixture of effect pigments of different colors. Thus, by simply laminating differently colored films on a solar cell module, a wide range of customized colors can be more easily reproduced and batch-to-batch color variations can be more easily suppressed.

[0034] The method according to the invention also enables the creation of different colors in the process step of solar cell module lamination rather than in the process step of film extrusion. Furthermore, when using multi-color encapsulation films, no additional production steps are required. Instead, the solar module manufacturer only needs to replace the non-colored encapsulation film with two or more colored encapsulation films or two or more colored encapsulation films of a multilayer.

[0035] Furthermore, since cost-effective tinting film production usually requires large batches of several tons, it is more efficient to produce a variety of tinting films in different colors that can be stockpiled and then combined in any way to produce the desired color according to the individual requirements of the solar cell module manufacturer, rather than mass-producing tinting films with specific pigment mixtures for each individual requirement.

[0036] The use of two or more layers containing effect pigments gives the appearance of the front surface of the solar cell different colors obtained by mixing primary colors such as red, green, blue, etc. In this way, solar module manufacturers can easily create a wide range of colors, for example beyond the three basic films, with red, green and blue on hand. There is no need to produce each color by a single film extrusion production. This solves the problem of simplifying color creation with colored encapsulation films and overcomes the limitations of single batch production. Therefore, the production of colored encapsulation films usually requires relatively large standard batches to achieve constant color and film quality. This batch is much larger than the single batch of encapsulation film required to cover the solar cell modules of a standard building in a single project. Therefore, using a batch or a group of customized colored encapsulation films in a standard amount, multiple individual project requirements can be met, making the production of colored encapsulation films more time and cost-effective.

[0037] The method according to the invention thus makes it easier to adjust the color, since different colors can be achieved simply by combining colored standard films instead of having to produce a film for each color.

[0038] For example, the color turquoise can be produced with layers of green and blue pigments, yellow can be produced with layers of red and green pigments, and pink can be achieved with layers of red and blue pigments.

[0039] The effect pigments used in the present invention provide color through light reflection rather than light absorption as with conventional dyes and pigments. The red, green and blue effect pigments can be selected to have similar transmission characteristics for light, typically all with transmission values ​​>80%. This makes it easier to create true colors with transmission values ​​>80%, even for colors like gray. This is another advantage of using an RGB film combination.

[0040] In addition to selecting the reflection color of the effect pigments in the individual TFCLs, the color combination can be further varied by varying the thickness of the individual layers and / or by varying the concentration of the effect pigments in the individual layers and / or by varying the number of individual layers of the same or different colors, for example by combining one or more first TFCLs of a first color with one, two or more second TFCLs of a second color and optionally with further TFCLs of other colors.

[0041] Furthermore, by uniaxially or biaxially stretching or pulling the front cover film to a certain extent before or during lamination of the solar module, a color-changing effect can be achieved on the surface, thereby creating a marble-like effect or patterns and structures. This is particularly useful when decorating buildings that require different color structures.

[0042] In a preferred embodiment of the present invention, the tinted solar cell or tinted solar cell module comprises two or more, preferably 2 to 6, very preferably two, three, four or five, most preferably two or three TFCLs, wherein at least one, preferably each TFCL contains an effect pigment of a color that is different from the color of the effect pigments in the other TFCLs.

[0043] In another preferred embodiment of the present invention, the tinted solar cell or tinted solar cell module comprises two or more, preferably two, three, four or five TFCLs, wherein at least one, preferably each TFCL contains an effect pigment of a color different from the effect pigments contained in the other TFCLs and selected from the group consisting of silvery white, yellow, red, green and blue effect pigments.

[0044] Since the effect pigments show a characteristic color by light reflection, the color effect is particularly visible against a dark or black background. Therefore, preferably, the colored solar cell or colored solar cell module according to the present invention comprises a black or dark (e.g. dark blue) back sheet, such as a black or dark back encapsulation sheet or film.

[0045] For typical applications, the concentration of effect pigments in TFCL should preferably be ≥1 g / m 2 , otherwise the solar cell structure would still be visible, while the color impression could already be strong. In addition to the higher hiding power, the angular dependence of the color of the solar cell module is also reduced. The combination of two or more primary colors (e.g. red, green and / or blue) opens up new possibilities for designing tinted solar cell modules in individually customized colors selected from a wide variety of colors.

[0046] It was also found that stacks of TFCLs, each containing effect pigments of a different color, are ideal for providing sufficient color without significantly reducing the overall solar cell efficiency. Long-term tests have shown a high level of stability. Since the direct contact between the layer containing effect pigments and the solar cell is the most demanding position in the solar module setup, it can be safely assumed that the layer containing effect pigments will also have no negative impact if used at any other position in the solar module stack.

[0047] Effect pigments reflect part of the incident visible light but let through the light required to generate energy via the photovoltaic process. Effect pigments can be oriented so that the angle of optimum efficiency can be changed and thus play with color and efficiency.

[0048] Layers with effect pigments can be easily applied to prior art solar cells, making their use more efficient. The process step of applying the layer containing effect pigments to the solar cell module can be easily integrated into the prior art existing processes for producing encapsulated solar cell modules.

[0049] By using the present invention, the visual appearance of solar cells can be adapted to specific needs. The external visual appearance of objects including solar cells, such as buildings, equipment, cars, etc., can be improved, and the transparency and reflectivity of solar cells can be controlled.

[0050] Furthermore, when a dark backsheet is used, the visibility of the cells and brightly coloured busbars can be reduced or even avoided, and the busbars and connection points are darkened. Furthermore, the invention can be used to provide solar cells with extraordinary colours to achieve special effects and designs, such as, depending on the effect pigments used, also adding textures, such as glitter effects on the panels, hues that mimic the surface of brick walls or different materials used in house construction.

[0051] Another advantage of the present invention is the possibility of seamlessly integrating solar cells into any surface by changing their appearance to a neutral appearance to which people are accustomed, such as into the surfaces of buildings (facades and roofs), handheld, portable and mounted devices, automobiles or other transport objects (cars, trucks, motorcycles, scooters, trains, ships, trailers, etc.), price tags, plastics, wearable items and household appliances or the like, or any other highly visible surface where it is necessary to seamlessly integrate solar cells without changing their optical appearance, or surfaces of other types of solar devices, where the typical technical appearance of the solar cells will be changed to a neutral appearance to which people are accustomed and where long-term stability is crucial.

[0052] Furthermore, the cost of solar power generation does not increase significantly, as the efficiency of the tinted solar cells is not affected much compared to currently available technologies, which have huge drawbacks that affect the performance of solar cells, which may drop from an initial performance of >15% to less than 10% under real-life conditions.

[0053] The coloring of solar cells according to the invention can be performed in a wide variety of colors and is not limited to rigid substrates such as glass or to single solar cell technology.

[0054] The effect pigments in the TFCL according to the invention are preferably selected from pearlescent pigments, interference pigments and multilayer pigments.

[0055] In a preferred embodiment of the invention, the effect pigments are selected from interference pigments. The optical effect of interference pigments is based on differences in the refractive index of materials, which are arranged in the form of thin layers one above the other in the pigment and reflect, transmit and possibly absorb incident light differently depending on the refractive index of the respective layer and the medium surrounding the interference pigment. The difference in the refractive index between adjacent layers leads to differences in the paths of the reflected light rays, so that they interfere with each other, and certain wavelengths of light are wavelength-selectively amplified or attenuated. Under appropriate conditions, the observer will perceive the reflected light in the visible wavelength region amplified in this way as visible interference colors. If all layers of the interference pigment consist of transparent, colorless materials, only the interference colors of the interference pigment can be perceived, but not the true color.

[0056] Optically, the interference colors of interference pigments without absorption colors behave like colored light, i.e. they combine with each other. Thus, for example, a stack of three TFCLs, each containing a different interference pigment selected from red, green and blue interference pigments (i.e. interference pigments that exhibit a red, green or blue interference color in the application medium), will give a gray or white hue.

[0057] The individual interference pigments usually consist of a flake-shaped support material and one or more more or less transparent layers applied thereto. However, the uniform layer thickness of the support and the individual layers, the uniformity of the composition of the individual layers, the surface properties of the support and the individual layers and the size and size distribution of the pigments determine, inter alia, the extent to which the optical behavior of the respective interference pigment deviates from the expected behavior of the material currently used.

[0058] The conditions for the preparation of interference pigments therefore have a significant influence on their optical behavior. Thus, depending on the manufacturer and the preparation process employed, and even on the respective batches, differences in optical behavior, such as saturation, brightness or color angle, may be observed for interference pigments of formally identical hue (e.g. red) and formally identical layer structures (e.g. titanium dioxide layers on mica flakes). However, these disadvantages can be overcome by using the method according to the invention, which enables the creation of a wide range of colors using, for example, three basic films with red, green and blue colors, without having to create each color in a single film production process, thereby circumventing the limitations of single batch production.

[0059] The effect pigments are preferably based on synthetic or natural mica, flaky glass substrates, flaky SiO2 substrates or flaky Al2O3 substrates. The flaky substrates are preferably coated with one or more layers of metal oxides and / or metal oxide hydrates of Ti, Sn, Si, Al, Zr, Fe, Cr and Zn.

[0060] The effect pigments used in the TFCL according to the invention are preferably transparent or at least translucent. The effect pigments that can be used in the invention preferably exhibit yellow, red, blue or green colors. However, other colors, such as gray, white, purple, red or orange are also suitable. Other colors or mixtures thereof can also be used to produce specific colors and shades. Effect pigments can also produce metallic effects, such as, but not limited to: silver, platinum, gold, copper and various other metals.

[0061] In a preferred embodiment of the present invention, each individual TFCL comprises only one type of effect pigment.

[0062] The effect pigments preferably comprise, and very preferably consist of, a transparent or translucent flake-form substrate coated with one or more layers of transparent or translucent material and optionally a post-coating.

[0063] Preferably, the effect pigments contain a flaky substrate which comprises at least one coating comprising a metal oxide, a metal oxide hydrate or a mixture thereof. Preferably, the effect pigments consist of a transparent or translucent, colorless, flaky substrate onto which one or more layers of a transparent or translucent colorless material have been applied. Pearlescent pigments, interference pigments and / or multilayer pigments are preferably used. The long-term stability of the effect pigments can preferably be improved by using an organic and / or inorganic coating as the last layer of the effect pigment, as described, for example, in WO 2011 / 095326 A1 and below.

[0064] Suitable substrates for effect pigments are, for example, all known coated or uncoated flake-shaped substrates, preferably transparent or translucent, preferably colorless flakes. For example, phyllosilicates, in particular synthetic or natural mica, glass flakes, SiO2 flakes, Al2O3 flakes, TiO2 flakes, liquid crystal polymers (LCP), holographic pigments, BiOCl flakes or mixtures of the flakes are suitable. According to the invention, aluminum flakes with a dielectric coating can also be used in low concentrations in order to obtain very high hiding power for the active photovoltaic layer.

[0065] The glass flakes can consist of all glass types known to the person skilled in the art, such as A glass, E glass, C glass, ECR glass, recycled glass, window glass, borosilicate glass, Glass, laboratory glass or optical glass. The refractive index of the glass flake is preferably 1.45 to 1.80, in particular 1.50-1.70. Particularly preferred glass flakes are composed of A glass, C glass, E glass, ECR glass, quartz glass and borosilicate glass.

[0066] Preference is given to coated or uncoated flakes of synthetic or natural mica, SiO2 flakes, Al2O3 flakes and glass flakes, in particular C glass, ECR glass or calcium aluminum borosilicate glass flakes. In particular, preference is given to using effect pigments based on calcium aluminum borosilicate glass. In a variant of the invention, preference is given to Al2O3 flakes.

[0067] The thickness of the substrates is generally between 0.01 and 5 μm, in particular between 0.05 and 4.5 μm, particularly preferably between 0.1 and 1 μm. The length or width dimensions are generally between 1 and 500 μm, preferably between 1 and 200 μm, in particular between 5 and 125 μm. Their aspect ratio (ratio of average diameter to average particle thickness) is generally between 2:1 and 25,000:1, preferably between 3:1 and 1000:1, in particular between 6:1 and 250:1. The stated dimensions of the flake-form substrates also apply in principle to the coated effect pigments used according to the invention, since the additional coating is generally only in the range of a few hundred nanometers and therefore does not significantly affect the thickness or length or width (particle size) of the effect pigments.

[0068] The particle size and particle size distribution of the effect pigments and their substrates can be determined by various methods commonly used in the art. However, laser diffraction methods using standard methods such as Malvern Mastersizer 2000, Beckman Coulter, Microtrac, etc. are preferably used. In addition, other techniques such as SEM (scanning electron microscopy) images can be used.

[0069] In a preferred embodiment, the substrate is coated with one or more transparent or semi-transparent layers comprising metal oxides, metal oxide hydrates, metal hydroxides, metal suboxides, metal fluorides, metal nitrides, metal oxynitrides or mixtures of these materials. Preferably, the substrate is partially or completely encapsulated by these layers.

[0070] In addition, effect pigments with a multilayer structure comprising high-refractive index layers and low-refractive index layers can also be used, wherein the high-refractive index layers and the low-refractive index layers preferably alternate. Particularly preferred are layer stacks comprising high-refractive index layers (refractive index ≥ 2.0) and low-refractive index layers (refractive index < 1.8), wherein one or more of these layer stacks may have been applied to a substrate. The sequence of high-refractive index layers and low-refractive index layers in the effect pigment can be matched to the pigment substrate so that the pigment substrate is included in the multilayer pigment structure.

[0071] Particularly preferred are metal oxides, metal oxide hydrates or mixtures thereof, preferably Ti, Sn, Si, Al, Zr, Fe, Cr and Zn, in particular Ti, Sn and Si. The oxides and / or oxide hydrates may be present in a single layer or in separate layers. In particular, titanium dioxide of the rutile or anatase modification, preferably the rutile modification, is used. In order to convert the titanium dioxide into the rutile modification, a tin dioxide layer is preferably applied below the titanium dioxide layer. Preferred multilayer coatings comprise alternating high refractive index layers and low refractive index layers, preferably, for example, TiO2-SiO2-TiO2.

[0072] The metal oxide, hydroxide and / or oxide hydrate layer is preferably applied by known wet-chemical methods, wherein wet-chemical coating methods developed for the preparation of effect pigments which result in the substrate being coated can be used. After wet-chemical application, the coated product is subsequently separated, washed, dried and preferably calcined.

[0073] The thickness of the individual layers in the effect pigments is generally from 10 to 1000 nm, preferably from 15 to 800 nm, in particular from 20 to 600 nm, especially from 20 to 200 nm.

[0074] To increase the light, temperature, water and weather stability, the effect pigments can be post-coated or post-treated. The post-coating can be an organic and / or inorganic coating as the last layer or layers. The post-coating preferably comprises one or more metal oxide layers of the elements Al, Si, Zr, Ce; Fe, Cr or mixtures or mixed phases thereof. In addition, organic or organic / inorganic combined post-coatings are possible. Silanes and / or organofunctional silanes can also be used alone or in combination with metal oxides. Suitable post-coating or post-treatment methods are, for example, the methods described in DE 22 15 191, DE-A 31 51 354, DE-A 32 35 017 or DE-A 3334 598, EP 0 090 259, EP 0 634 459, WO 99 / 57204, WO 96 / 32446, WO 99 / 57204, US Pat. No. 5,759,255, US Pat. No. 5,571,851, WO 01 / 92425, WO 2011 / 095326 or other methods known to those skilled in the art.

[0075] The effect pigments which can be used in the present invention are, for example, those sold under the trade name and Lumina Commercially available interference pigments or pearlescent pigments are provided. Other commercially available effect pigments can also be used. In particular, and pigment.

[0076] A single TFCL according to the invention may also contain a mixture of two or more, preferably three or more, different effect pigments, very preferably a mixture of one or more of silvery white, yellow, red, green and blue effect pigments. Depending on the concentration of the individual effect pigments, an even wider color space / range can thereby be achieved and other special effects can be obtained. In this preferred embodiment, the effect pigments can be mixed in any proportions, but preferably the total content of all effect pigments in one TFCL should not exceed 40% by weight, more preferably not more than 10% by weight.

[0077] However, in a preferred embodiment, each individual TFCL according to the invention does contain effect pigments of only one colour, preferably selected from the group consisting of silver-white, yellow, red, green and blue.

[0078] The concentration of effect pigments in a single TFCL according to the invention is preferably from 0.01 to 20 wt.-%, very preferably from 0.02 to 15 wt.-%. More preferably, the concentration of effect pigments in a single TFCL according to the invention is from 0.05 to 10 wt.-%, even more preferably from 0.1 to 5 wt.-%, most preferably from 0.1 to 1 wt.-%.

[0079] In another preferred embodiment, each m of a single TFCL according to the present invention 2 The amount of effect pigment is 0.1g / m 2 Up to 75g / m 2 In the range of 0.2-30 g / m 2 In the range of 0.5-15 g / m 2 , most preferably 0.5-6g / m 2 .

[0080] In addition to the effect pigments, the TFCL may also contain one or more additives. For example, it may contain one or more light scattering centers or light scattering particles, which provide haze in the pigmented layer, which advantageously reduces the appearance of dark patterns in the shape of solar cell array structures or electrical interconnection busbars, but on the other hand does not significantly reduce the transmittance of the pigmented layer and therefore does not negatively affect the power conversion efficiency of the solar cell. For example, suitable and preferred light scattering centers and particles are disclosed in CN113809194A.

[0081] In a preferred embodiment, the TFCL contains one or more light scattering particles selected from the group consisting of silica spheres or powders, spherical silicone powders, BaSO4, Al2O3, BaMgAlO x Or Eu-doped BaMgAlO x The particles or glass bubbles are preferably in a concentration of 0.001-10 wt.%, more preferably 0.005-10 wt.%, even more preferably 0.005-5 wt.%, very preferably 0.005-3 wt.%, most preferably 0.01 to 1.5 wt.%, further preferably 0.1-10 g / m 2 .

[0082] The TFCL according to the invention containing effect pigments is preferably selected from polymer films or sheets.

[0083] Preferred polymer films are selected from polyolefin polymers or copolymers, in particular polyethylene polymers or copolymers, including but not limited to polyethylene, EVA (ethylene vinyl acetate), EBA (ethylene butyl acrylate), EMA (ethylene methyl acrylate), EEA (ethylene ethyl acrylate), POE (polyolefin elastomer), BPO (polyolefin copolymer), in addition to PVB or TPU (thermoplastic polyurethane), preferably EVA or polyethylene copolymer.

[0084] In another preferred embodiment, the front transparent cover layer is a polymer film or sheet, which is incorporated into the solar cell module or architectural glass facade.

[0085] The thickness of a single effect pigment-containing TFCL is preferably in the range of 5 μm to 1000 μm, more preferably 20 μm to 800 μm, even more preferably 100 μm to 300 μm.

[0086] Effect pigments and optional additives, such as light-scattering particles, can be incorporated into the TFCL according to the invention by methods known to the person skilled in the art and described in the literature.

[0087] If the TFCL according to the invention is a polymer film, it can be produced, for example, by an extrusion process, for example by melt extrusion of a polymer material, wherein the effect pigments and optionally additives are added to the polymer melt before extrusion.

[0088] During the extrusion process, the thermoplastic is melted in the screw into a viscous mass which is then pressed through a flat film die. The possible shapes are extremely diverse. Films, foils and sheets are extruded through a flat die.

[0089] Finally, the polymer film is usually structured on heated and structured rollers, for example embossed, in order to enable better air evacuation during the lamination of the solar module. According to the invention, one or more layers of the multilayer stack can be structured. Structuring or embossing of each individual film can improve the orientation of the effect pigments in the film, especially for very thin films, and can therefore also be used for the appearance of the stack of individual TFCL films.

[0090] Masterbatches or compounds are usually used to color the molten mass with effect pigments and optional additives. In order to achieve satisfactory results in the extrusion of plastics with effect pigments and optional additives, a balanced ratio must be maintained between the energy of the mixture and the effect pigments and / or additives, which are as undamaged as possible. Excessive shearing in the mixing section or unsuitable screws or filters can destroy the effect pigments and significantly reduce the pearlescent effect. The orientation of the pigments is crucial for a uniform effect. This must be ensured in the process by appropriate engineering and mechanical design.

[0091] In a preferred embodiment of the invention, a masterbatch is added during extrusion of the polymer film, the masterbatch comprising the desired amount of effect pigments and optional additives in the polymer material, for example 5 to 30% by weight. This can be achieved, for example, by premixing the color masterbatch particles with the EVA particles or by any other known method.

[0092] Due to the shear forces acting on the effect pigments during the melt extrusion process, the effect pigments are oriented substantially parallel to the encapsulation film surface.

[0093] In another preferred embodiment, the TFCL containing one or more effect pigments and one or more scattering particles is a coextruded film of two or more layers of the same or different polymer materials, wherein at least one layer, preferably the layer facing the front sheet, contains one or more effect pigments.

[0094] In another preferred embodiment, two or more TFCLs are extruded under heat, optionally together with other preceding layers, to form a fused multilayer stack.

[0095] EVA, used as an encapsulant for PV module lamination, is a thermoplastic polymer whose formulations are particularly suitable for solar applications. It has high electrical insulation, transparency, flexibility and softness. In cross-linked formulations (e.g. encapsulation), it also exhibits high dimensional stability, fast curing and easy lamination. In addition to the polymer resin, common EVA formulations usually include cross-linkers, adhesion promoters, UV absorbers, UV stabilizers and antioxidants. The cross-linker is a free radical initiator, usually a peroxide, which decomposes when heated during the lamination process to form free radicals that initiate free radicals on the polymer backbone. The free radicals formed in turn lead to the formation of covalent bonds between the polymer chains.

[0096] According to the invention, the TFCL containing effect pigments may also be a glass, enamel or ceramic layer. Thus, in another preferred embodiment, at least one of the TFCLs, preferably exactly one, is a glass, enamel or ceramic layer, while the other TFCLs are selected from polymer films or sheets. For example, according to this preferred embodiment, a first TFCL may be provided, which is a glass, enamel or ceramic layer containing a first effect pigment (e.g. silvery white or another color), and a second TFCL containing a second effect pigment and optionally further TFCLs each containing an effect pigment are laminated thereon, wherein these second and further TFCLs are polymer films, the second and further effect pigments being selected, for example, from yellow, red, green and blue effect pigments.

[0097] However, it is generally more preferred to use polymer films as TFCLs in order to take full advantage of the above-mentioned advantages related to flexibility and reproducibility when providing customized colors on a large scale.

[0098] If the TFCL containing effect pigments is a glass, enamel or ceramic layer, its thickness is preferably from 5 μm to 200 μm, very preferably from 10 μm to 100 μm, most preferably from 15 μm to 70 μm.

[0099] TFCLs as glass layers can be prepared, for example, by mixing one or more effect pigments and optional additives with a glass frit or flux, a ceramic or one or more enamel precursors, placing the mixture on a substrate, and firing or sintering the mixture at a temperature above the glass temperature of the glass frit, glass flux, ceramic and enamel, respectively. Typical methods of applying the precursor composition to a substrate include roller coating, screen printing or spraying a mixture of glass flux, enamel or ceramic precursor, pigment and optional other additives in a solvent such as water or glycol ethers.

[0100] Especially in the decoration of glass products, especially glass sheets, it is preferred to use a precursor composition, which contains one or more pigments, one or more optional additives and one or more glass frits or glass fluxes. The precursor composition is fired after being applied to the substrate to form a glass-enamel containing the pigment and the optional additives. When the precursor composition is applied to the glass sheet, the melting behavior of the precursor composition should be adjusted according to the typical conditions of the tempering process. The usual firing conditions are that the glass temperature is about 580°C to 650°C and the firing time is a few minutes. For the colored decoration of glass sheets in the field of building and instrument glass, good compatibility is required between the glass frits contained in the composition and the inorganic pigments. In many fields of use, the requirements of the firing composition (i.e., glass enamel) include stable operation at the lowest possible temperature with a short firing time, avoiding cracks, having good chemical resistance to acid and alkali materials, and good weather resistance. The preferred glass flux is a cadmium-free and lead-free glass flux with silicon, zinc and boron as the main components, for example based on borosilicate glass.

[0101] The TFCL according to the invention also allows to provide shades or color patterns, for example for imitating a brick wall, which can be achieved by, for example, screen printing two different colors in the desired pattern, or shades for different surfaces of materials for house construction, which can be achieved by, for example, spraying two different shades on each other.

[0102] The effect of pigments and layers on c-Si solar cells can be evaluated through reflection data. The reflection data is used to estimate the maximum power absorption / maximum photocurrent generation of the treated cells. Reflection and transmission measurements and calculations are performed by common methods known to those skilled in the art, as further described in the experimental section.

[0103] For light in the range of 500 to 800 nm, more preferably in the range of 400 to 1000 nm, most preferably in the range of 300 to 1150 nm, the transmission of a single TFCL containing effect pigments is preferably ≥50%, more preferably ≥70%, very preferably ≥80%.

[0104] For light with a wavelength of 500 to 800 nm, more preferably in the range of 400 to 1000 nm, most preferably in the range of 300 to 1150 nm, the reflectivity of a single TFCL containing effect pigments is preferably ≤50%, more preferably ≤30%, very preferably 1 to 20%. Colors can already be seen at low reflectivity values ​​of 1-5%.

[0105] A preferred colored solar cell or colored solar cell module comprises the following components:

[0106] - two or more TFCLs containing effect pigments as described above and below,

[0107] - optionally, one or more further transparent layers on the front side of the solar cell,

[0108] - one or more solar cells, or an array of solar cells electrically interconnected by conductive members, preferably by bus bars,

[0109] -optionally, a rear encapsulation sheet,

[0110] -Back piece.

[0111] Figure 1 , a colored solar cell module according to the invention is shown exemplarily and schematically, comprising a front sheet (11), three TFCLs (12a, b, c), each containing different effect pigments, which can also be used as a front encapsulation sheet, a solar cell pattern or array with bus bars (13), an optional rear encapsulation sheet (14) and a rear sheet (15). The arrow indicates the direction of the incident light.

[0112] The number of pigmented TFCLs (12a, b, c) can also vary, for example to two, four, five or six individual layers. The TFCLs can also be laminated and pressed together under heat, optionally with a transparent front sheet (11), to form an integral multilayer.

[0113] In another preferred embodiment ( Figure 1 (not shown), one or more front encapsulation films (16) are provided between the front sheet (11) and the pigment-containing layer (12a, b, c) or between the pigment-containing layer (12a, b, c) and the solar cell (13). The front encapsulation film (16) does not contain effect pigments.

[0114] In another preferred embodiment ( Figure 1 ), the solar cell module does not include a front sheet (11), and the TFCL (12a, b, c) containing effect pigments is used as the front sheet.

[0115] In another preferred embodiment ( Figure 1(not shown), one or more TFCLs (12a, b, c) (preferably the outermost TFCL (12a)) are used as one or more front encapsulation sheets.

[0116] In another preferred embodiment ( Figure 1 A protective foil or outer foil is applied on top of the finished solar cell or solar cell module (not shown in FIG. 1 ).

[0117] The TFCLs (12a, b, c) are located on the radiation receiving side, i.e. in the visible part of the solar cell or solar cell module according to the invention. They can be located in the solar cell module on the inside of the front sheet (11), i.e. on the side facing the solar cell or solar cell array, such as Figure 1 As shown, or alternatively, they may be located on the outside of the front sheet (11), ie on the side facing the incident light.

[0118] The TFCLs (12a, b, c) can be applied topically and flexibly to any surface. Thus, they can be applied to the outside of a finished solar cell or solar cell module, on a protective substrate (glass or plastic) covering the solar cell or solar cell module, or directly on the photoactive material / solar cell.

[0119] Advantageously, the TFCL (12a, b, c) may also function as an anti-reflection film.

[0120] Typically, components on the front side of the solar cell module, such as the front sheet (11), TFCL (12a, b, c) and optional other front encapsulation films, are substantially transparent to incident light passing through the solar cell or solar cell array (13).

[0121] If one or more layers or sheets (11, 12a, b, c, 14, 15, 16) of the front and back sides are polymer films, they are preferably selected from organic polymers, including but not limited to polyolefins, such as polyethylene polymers or copolymers, such as polyethylene, EVA (ethylene vinyl acetate), EBA (ethylene butyl acrylate), EMA (ethylene methyl acrylate), EEA (ethylene ethyl acrylate), POE (polyolefin elastomer), BPO, in addition to polyesters, polyamides, polyurethanes, polyvinyl butyral PVB, polycarbonates, polyvinyl chloride, polyvinyl acetate, polyacrylates, polyols, polyisocyanates or polyamines, as well as copolymers, resins, blends or multilayers of the above, such as polyurethane resins containing polycarbonate, polyurethane resins containing vinyl chloride vinyl acetate, acrylic resins, polyurethane acrylate resins, polyester resins or TPU (thermoplastic polyurethane), very preferably TPU or polyolefins, including but not limited to EVA, EBA, EMA, EEA, POE or BPO, most preferably EVA.

[0122] The TFCL (12a, b, c), the optional front encapsulation sheet (16) and the optional back encapsulation sheet (14) are preferably selected from polyolefin polymer or copolymer films, very preferably from polyethylene polymer or copolymer films, in particular from EVA, EBA, EMA, EEA, POE, BPO, PVB or TPU films, most preferably from polyethylene copolymers or EVA films.

[0123] The front sheet (11) and the back sheet (15) are preferably selected from glass sheets. In another preferred embodiment, the front sheet (11) and / or the back sheet (14), more preferably the back sheet (15) is a polymer sheet, such as TPT or polycarbonate sheet.

[0124] Other preferred polymers used as or in the backsheet (15) can be divided into difluoropolymers, monofluoropolymers and non-fluoropolymers and various structures within each category. The difluoropolymer backsheet is indeed usually composed of Polyvinyl fluoride (PVF) film or The outer layer of polyvinylidene fluoride (PVDF) film and the sandwich layer of polyethylene terephthalate (PET) are composed. The monofluoropolymer backsheet is usually composed of Tedlar or And the inner side of the PET and primer or EVA layer. The non-fluoropolymer back sheet usually consists of two layers of PET and a layer of primer or EVA.

[0125] In a preferred embodiment of the present invention, the rear sheet (15) is a dark color such as black or dark blue, and / or a black or dark sheet, such as a rear encapsulation sheet (14), is provided on the rear side of the solar cell or solar cell module, i.e., between the solar cell (13) and the rear sheet (15), wherein the dark color is preferably dark blue which is equal to the color of the solar cell.

[0126] like Figure 1 The solar cell array ( 13 ) shown as an example can also be replaced by a single solar cell.

[0127] The colored solar cell or the colored solar cell module according to the present invention and Figure 1The solar cell (13) in the embodiment can be selected from any type of device for collecting and converting solar energy, such as solar thermal devices or photovoltaic devices, including but not limited to organic photodiodes, solar cells or solar cell modules, which can be organic, inorganic or hybrid types, including but not limited to amorphous, monocrystalline silicon and polycrystalline silicon solar cells, CIGS, CdTe, III / V solar cells, II / VI solar cells, perovskite solar cells, organic solar cells, quantum dot solar cells and dye-sensitized solar cells, as well as solar cell modules made of a single cell. Crystalline solar cells include, for example, Al-BSF, PERC, PERL, PERT, HIT, IBC, bifacial cell structures or any other cell type based on a crystalline silicon substrate.

[0128] The colored solar cell or the colored solar cell module according to the present invention and Figure 1 The solar cell (13) may also be selected from devices that collect and convert solar energy, such as solar thermal devices or photodiodes.

[0129] In the solar cell (13), the conductive component preferably comprises a metal-based conductive component, including but not limited to the following components:

[0130] i) an H-grid consisting of main vertical connectors, the so-called busbars,

[0131] ii) horizontal current collecting components - so-called grid lines,

[0132] iii) Connectors and solder between cells,

[0133] In a preferred embodiment of the present invention, in order to achieve a completely uniform appearance of the solar cell (13), before applying the layer (12) with effect pigments and light scattering centers, the metal-based conductive parts, including but not limited to the above-mentioned components i) to iii), are preferably colored black or a dark color, such as dark solar blue.

[0134] In another preferred embodiment of the invention, a dark grid, preferably black or dark blue, is incorporated into one or more layers of the solar cell, said grid covering the bright areas, such as the spaces between the individual solar cells and the conductive parts (including bus bars, conductive paths and soldering points). In another preferred embodiment of the invention, a black or dark blue backing layer is applied behind the solar cell in order to hide the spaces between the individual solar cells. The black or dark blue backing layer can be printed or applied as a foil.

[0135] Suitable and preferred methods for darkening otherwise white appearing metal parts of a solar cell (13) having an H-grid front pattern include covering the metal strips with a black polymer foil or painting the metal parts with black paint. In the case of a printed silver H-grid, the silver color can be directly darkened by forming a thin layer of silver sulfide (for example by treatment with H2S) or by copper plating and oxidation. In the case of a plated metal grid, the top layer of the metal stack can be directly plated with a strongly absorbing metal oxide or sulfide, such as CuO or Ag2S or similar dark metal oxides or others. According to the present invention, in the case of using new metallization schemes (such as smart wire technology), blackened wires or wires with a microstructure that reduces reflectivity can also be used to darken the appearance of the metal grid. If a black or dark solar blue backsheet is used as the module background, a very uniform appearance of the entire module can be achieved even when viewed from a very close distance.

[0136] The colored solar cells and the colored solar cell modules according to the invention can be produced by methods and means known to the person skilled in the art and described in the literature.

[0137] For example, existing techniques for manufacturing encapsulated solar cell modules typically include building a stack of front glass and solar cells mounted with busbars embedded in an encapsulation film laminated to a back sheet or glass. The stack is then heated to, for example, 130°C to 160°C (depending on the type of encapsulation material used) and pressed together by vacuum or any other type of physical pressure.

[0138] Preferably, the TFCL with effect pigments and the other individual components or layers of the solar cell module as described above and below are stacked in the desired sequence and then laminated together, for example by applying heat and / or pressure, or using an adhesive or bonding agent.

[0139] Alternatively, the lamination process for producing one or more solar cell modules can also be carried out in two steps, so that in a first lamination (or pre-lamination) step the layer containing the effect pigments is laminated onto the front sheet and then in a second lamination step the front sheet plus the lamination layer containing the effect pigments is laminated onto the stack of the remaining components.

[0140] A preferred method for producing a tinted solar cell or a tinted solar cell module according to the invention comprises the step of laminating two or more TFCLs containing effect pigments as described above and below to the front side of the solar cell or solar cell module, wherein the effect pigments in at least two TFCLs have different colors.

[0141] The lamination step may be performed using standard methods, such as in a laminator, by applying heat and pressure to the two layers for a certain time interval, such as by applying a vacuum and / or any other form of physical pressure.

[0142] Alternatively and / or additionally, lamination can be achieved or supported by using one or more adhesives and / or bonding agents or layers. The adhesive / bonding agent can be reactive or non-reactive and can include or consist of natural or synthetic sources. Suitable and preferred examples include, but are not limited to, polyurethane (PUR), thermoplastic polyurethane (TPU), rubber, acrylic and silicone adhesives, depending on the desired application.

[0143] In the lamination step, suitable applied heat and pressure and time intervals depend on the type of sheet and film used and can be easily selected by a person skilled in the art. In the case of using a front glass sheet and an EVA polymer film, the heating temperature is preferably in the range of 130° C. to 160° C., very preferably about 135° C., and the time interval is preferably 20 to 30 minutes. Preferably vacuum pressing is used. Preferably a pressure of 400 to 900 mbar is applied.

[0144] After the last lamination step, the laminate stack is cooled, preferably to room temperature. Excess material of the encapsulation film and back sheet (in case a plastic back sheet is used) can be cut off, and a junction box can be attached for electrical connection of the solar cell module. Finally, the stack can be framed.

[0145] After one or more lamination steps, the film thickness will generally decrease depending on the lamination conditions.

[0146] Preferably, the resulting stack is completely sealed and, ideally, can protect the solar cells for at least 25 years.

[0147] Preferably, the solar cells and solar cell modules according to the invention show a power variation ΔP of >−20%, more preferably >−10%, very preferably >−6%, wherein

[0148]

[0149] P i A solar cell or solar cell module SC according to the invention having a layer comprising effect pigments and scattering centers as described above and below i Power; P ref is a layer having the same properties as SC except that the layer having effect pigments does not contain any optional additives i Reference solar cell or solar cell module SC of the same component ref Therefore, a negative value of ΔP indicates a power loss relative to the reference; a positive value of ΔP indicates a power gain relative to the reference.

[0150] The following examples are intended to illustrate the present invention without limiting the present invention.

[0151] Example 1 - Colored polymer film stack

[0152] Different polyethylene films according to the invention were prepared which contained 0.15% of effect pigments, resulting in an effect pigment concentration of about 1 g / m 2 .

[0153] Although encapsulating films are usually prepared by extrusion cast film, in this example, for practical reasons, film samples with dimensions of 10 x 15 cm and a thickness of 700 μm were prepared by injection molding of polyethylene resin containing pigment and particles as shown below:

[0154] A Kraus-Maffei CX-130-380 injection molding machine was used. After the mold was closed, the transparent plastic melt ( 28-25PV, Arkema product) is injected into the injection mold. The injection operation is performed at a temperature in the range of 180 to 200 ° C and a pressure of 450 to 900 bar (4.5x10 7 N / m 2 Up to 9x10 7 N / m 2 ) is carried out under pressure. To color the plastic melt or add scattering particles, masterbatches are used in the desired concentration. If necessary, the polymer film can be embossed in a subsequent step. The embossed structure usually supports the removal of air during the lamination step of the solar module.

[0155] A black EVA film with dimensions of 10x6 cm was placed on a 6x12 cm glass sheet, leaving part of the glass uncovered. A film containing red effect pigment ( T30-21 Color Space red) EVA film, containing green effect pigment ( T30-24 Color Space green) and EVA film containing blue effect pigments ( T30-23 Color Space blue) EVA film, the thickness of each film is 450μm (450g / m 2 ), with dimensions of 6x12 cm. The red, green and blue effect pigments are interference pigments consisting of a natural mica substrate and a TiO2 coating. On top of this, a second 6x12 cm glass sheet is placed. The stack is then placed in a vacuum bag and put into an oven. The stack is treated at 150°C, 70 kPa for 10 minutes. After cooling, the sample is removed from the vacuum bag.

[0156] A grey multilayer film was achieved. Transmission measurements were performed on the sections where the black EVA was not placed. The transmission was compared to a non-pigmented standard laminate stack and the results showed that the effect pigments only resulted in a transmission reduction of less than 20%.

[0157] Example 1 - Stacking of tinted polymer film and tinted glass

[0158] Membrane preparation

[0159] Preparation containing 0.15% effect pigments EVA film of T30-24 Color Space Green, with a concentration of effect pigments of 1 g / m at a film thickness of 450 μm 2 .

[0160] Preparation of tinted glass front

[0161] Using existing screen printing technology, the effect pigments A layer of the aqueous glass / glass frit mixture of T30-23Color SpaceBlue was printed directly on commercial glass for solar modules to give a wet layer of 35-40 μm. The printed glass was tempered in an oven at 600°C-680°C to give a thickness of 20-25 μm with an effect pigment concentration of 1 g / m 2 of the glass-enamel dry layer.

[0162] Sample preparation

[0163] The samples were prepared to form the following layers:

[0164] -10cm x 10cm and 2mm thick colorless glass

[0165] -Black EVA film 10cm x 5cm

[0166] -10cm x 10cm colored encapsulation EVA film (450μm), with 1g / m 2 T30-24 Color SpaceGreen coloring

[0167] -10cm x 10cm and 2mm thick tinted glass, use 1g / m 2 T30-23Color SpaceBlue coloring

[0168] - Treat the stack in a vacuum bag at -70 kPa and 150 °C for 10 minutes in a drying chamber

[0169] After cooling, the sample was removed from the vacuum bag. A multilayer of turquoise color was achieved.

[0170] Transmission measurements were taken on sections where no black EVA film was placed. The transmission was compared to the transmittance of a non-pigmented standard laminate stack and the results showed that the effect pigments only resulted in a transmission reduction of less than 20%.

Claims

1. A tinted solar cell or tinted solar cell module comprising two or more transparent front cover layers, each of which contains at least one effect pigment having a specific color and consisting of a transparent or translucent flake-like substrate coated with one or more layers of transparent or translucent material and an optional back coating, wherein at least one transparent front cover layer contains an effect pigment of a different color from one or more effect pigments contained in one or more other transparent front cover layers.

2. The tinted solar cell or tinted solar cell module according to claim 1, wherein the transparent front cover layer is selected from polymer films or sheets.

3. The tinted solar cell or tinted solar cell module according to claim 1 or 2, wherein the transparent front cover layer is selected from EVA, EBA, EMA, EEA, POE, PC, BPO, PVB or TPU film. 4 . The tinted solar cell or tinted solar cell module according to claim 1 , wherein the transparent front cover layer is an encapsulation film or a component thereof or together forms an encapsulation film or a component thereof.

5. A tinted solar cell or tinted solar cell module according to one or more of claims 1 to 4, comprising two or more, preferably two, three, four or five transparent front cover layers, wherein at least one, preferably each, transparent front cover layer contains effect pigments having a color that is different from the color of one or more effect pigments contained in one or more other transparent front cover layers.

6. A tinted solar cell or tinted solar cell module according to one or more of claims 1 to 5, comprising two or more, preferably two, three, four or five transparent front cover layers, wherein at least one, preferably each, transparent front cover layer contains an effect pigment whose color is different from the color of the one or more effect pigments contained in one or more other transparent front cover layers and is selected from the group consisting of silvery-white, yellow, red, green and blue effect pigments.

7. A colored solar cell or a colored solar cell module according to one or more of claims 1 to 6, characterized in that The concentration of the effect pigments in each individual transparent front cover layer is from 0.02 to 15% by weight.

8. The tinted solar cell or tinted solar cell module according to one or more of claims 1 to 7, wherein the transmittance of each transparent front cover layer for light with a wavelength of 500 nm to 800 nm is ≥50%, preferably ≥70%, most preferably ≥80%.

9. A colored solar cell or a colored solar cell module according to one or more of claims 1 to 8, wherein the thickness of each individual transparent front cover layer containing effect pigments is in the range of 5 μm to 1000 μm, preferably 20 μm to 800 μm, very preferably 100 μm to 300 μm.

10. A colored solar cell or a colored solar cell module according to one or more of claims 1 to 9, characterized in that The effect pigments are selected from pearlescent pigments, interference pigments and multilayer pigments.

11. A colored solar cell or a colored solar cell module according to one or more of claims 1 to 10, characterized in that The effect pigments are based on synthetic or natural mica, flake-form glass substrates, flake-form SiO 2 substrates or flake-form Al 2 O 3 substrates.

12. The colored solar cell or colored solar cell module according to claim 11, characterized in that: The flake-like substrate is coated with one or more layers of metal oxides and / or metal oxide hydrates of Ti, Sn, Si, Al, Zr, Fe, Cr and Zn.

13. A tinted solar cell or tinted solar cell module comprising the following components: - two or more transparent front covers as defined in one or more of claims 1 to 12, - optionally one or more further transparent layers on the front side of the solar cell, - one or more solar cells, or an array of solar cells electrically interconnected by electrically conductive members, preferably bus bars, - optional post-encapsulation sheet, -Back piece.

14. The colored solar cell or colored solar cell module according to claim 13, characterized in that: The back sheet is black or dark in color, and / or the tinted solar cell or tinted solar cell module comprises an additional sheet or packaging film disposed between one or more solar cells or solar cell arrays and the back sheet, wherein the additional sheet or packaging film is black or dark in color.

15. A method for producing a tinted solar cell or a tinted solar cell module according to one or more of claims 1 to 14, comprising the step of laminating two or more transparent front cover layers as defined in one or more of claims 1 to 12 to the front side of the solar cell or solar cell module, wherein at least one transparent front cover layer contains effect pigments having a color that is different from the color of one or more effect pigments contained in one or more other transparent front cover layers.

16. The method according to claim 15, characterized in that The lamination step is performed by applying heat and / or pressure, or by using an adhesive or bonding agent or layer, preferably in a vacuum press.

17. A building device or equipment comprising one or more tinted solar cells or tinted solar cell modules according to one or more of claims 1 to 14, wherein the building device or equipment is selected from the group consisting of windows, doors, building facades, building roofs or floors, walls, structural glass, curtain walls, exhibition halls, car roofs, car bodies, mobile phones, handheld PCs such as tablets, plug-in solar modules, roof tiles, solar panels, PV fences, military equipment, radios, radio equipment, music boxes, mobile power banks, watches, glasses and goggles.

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