Solar cell

Abstract

The present invention relates to a solar cell or a solar cell module comprising a layer on or in the front radiation-receiving side of the solar cell, the layer comprising an effect pigment consisting of a transparent or translucent flaky substrate coated with one or more layers of a transparent or translucent material and optionally coated with a back coating, and to a method for their preparation.

Description

[0001] This divisional application is a divisional application of Chinese patent application No. 201880082200.2, filed on December 20, 2018, entitled "Solar Cell". Technical Field

[0002] This invention relates to solar cells or solar cell modules comprising a layer containing effect pigments, the effect pigments being composed of a transparent or translucent sheet-like substrate coated with one or more layers of transparent or translucent material and optionally coated with a post-coating layer, and methods for preparing them. Background Technology

[0003] Solar cells have demonstrated tremendous success in recent years and are projected to surpass 100 GW of grid-connected installations globally each year by 2017, with the majority of these installations being utility-scale. The fundamental function of all solar cells is the same: photoactive materials absorb light and generate excited electron-hole pairs. These electron-hole pairs are separated within the solar cell by regions with different mobilities for electrons and holes—so-called pn junctions. Because different types of light-absorbing materials can be used, the solar industry knows several different types of solar cell technologies:

[0004] 1) Crystalline silicon solar cells (monocrystalline c-Si and polycrystalline mc-Si)

[0005] 2) Cadmium telluride (CdTe) solar cells

[0006] 3) Copper-indium-gallium-diselenide (CIGS / CIS)

[0007] 4) Amorphous silicon solar cells (a-Si)

[0008] 5) III / V solar cells, such as gallium arsenide (GaAs) solar cells, or multijunction solar cells, which consist of stacks of Group III and Group V elements such as germanium / indium-(aluminum)-gallium-arsenide or phosphide (In(Al)GaAs / P).

[0009] 6) Dye-sensitized solar cells (DSSC)

[0010] 7) Organic solar cells (OSC)

[0011] 8) Perovskite solar cells (PSC)

[0012] 9) Quantum dot solar cells (QSC)

[0013] 10) Other II / VI solar cells composed of Group II and Group VI elements, such as zinc selenide (ZnSe) or iron sulfide (FeS).

[0014] 11) Cascaded solar cells.

[0015] However, using more building surfaces and other surfaces on objects (such as cars) increases the total surface area available for solar energy production. For this new technology and approach, the fabrication of solar cells with attractive colors and the improvement of efficiency at different absorption angles are of primary interest to the solar energy business.

[0016] JP 5648906 B2 describes the use of pigments for cooling in solar cells. The pigments are used to reflect a portion of IR solar radiation to reduce the operating temperature of the solar cell. WO 07 / 050756, WO 09 / 143407, and US2011 / 023943 disclose protective plates comprising polymer films and layers of selected special polymers, optionally containing stabilizers, dyes, pigments, flakes, other additives, or mixtures thereof for photovoltaic modules.

[0017] Currently, the options and technologies for obtaining colored solar cells are limited:

[0018] (1) Limited color options using Si-layers and other technologies;

[0019] (2) Coloring is achieved by altering the anti-reflective coating;

[0020] (3) Use colored glass;

[0021] (4) Use a reflective intermediate layer.

[0022] Most technologies and materials do not offer satisfactory colors, and coloring is accompanied by a significant loss of solar cell efficiency, or they are expensive due to high production costs (multilayer technology). Efficiency losses can range from 15% to 40%. Summary of the Invention

[0023] The purpose of this invention is to provide an effective material and method for coloring existing solar cells or solar cell modules.

[0024] This objective is achieved by the following subject: a solar cell or solar cell module comprising at least one layer on or on the front radiating receiving side of the solar cell or solar cell module, the layer comprising at least one effect pigment consisting of a transparent or translucent flake-like substrate coated with one or more layers of transparent or translucent material and optionally coated with a post-coating layer, and a method wherein a coating composition comprising such effect pigment is applied to the solar cell or solar cell module.

[0025] Specifically, the present invention provides the following technical solutions:

[0026] Project 1. A solar cell or solar cell module, comprising at least one layer on or on the front radiating receiving side of the solar cell or solar cell module, the layer comprising at least one effect pigment consisting of a transparent or translucent flake-like substrate coated with one or more layers of transparent or translucent material and optionally coated with a post-coating.

[0027] Project 2. The solar cell or solar cell module according to Project 1, wherein the effect pigment and / or the effect pigment layer selectively reflects 1-100% of the visible light of the solar spectrum, preferably 5-40%.

[0028] Item 3. A solar cell or solar cell module according to one or more of Items 1 to 2, wherein the effect pigment and / or the effect pigment layer has at least 30%, preferably >80%, of transparency for radiation associated with a particular solar cell or solar cell module, preferably for radiation in the range of 260 to 1200 nm.

[0029] Item 4. A solar cell or solar cell module according to one or more of Items 1 to 3, wherein the effect pigment and / or the effect pigment layer has a reflectance level of 1 to 40%, preferably <30%, for radiation in the range of 260 to 1200 nm.

[0030] Item 5. A solar cell or solar cell module according to one or more of Items 1 to 4, wherein the effect pigment and / or the effect pigment layer has a reflectance level of <20%, preferably <10%, for radiation in the range of 260 to 1200 nm.

[0031] Project 6. A solar cell or solar cell module according to one or more of Projects 1 to 5, wherein the effect pigment is selected from pearlescent pigments, interference pigments and multilayer pigments.

[0032] Item 7. A solar cell or solar cell module according to one or more of Items 1 to 6, wherein the amount of the effect pigment in the application medium is in the range of 1-40% by weight, preferably 1-15% by weight, based on the solid portion of the application medium.

[0033] Project 8. A solar cell or solar cell module according to one or more of Projects 1 to 7, wherein the amount of said effect pigment is between 0.1 and 75 g / m³. 2 Within the range.

[0034] Item 9. A solar cell or solar cell module according to one or more of Items 1 to 8, wherein the thickness of the layer containing the effect pigment is in the range of 1 to 200 μm.

[0035] Item 10. A solar cell or solar cell module according to one or more of Items 1 to 9, wherein the internal quantum efficiency is ≥0.7, preferably ≥0.8, in the wavelength region of 260 to 1200 nm.

[0036] Item 11. A solar cell or solar cell module according to one or more of Items 1 to 10, wherein the effect pigment and / or the effect pigment layer generates a relative current loss [A / m]. 2 The content should be less than 40%, preferably less than 30%, and most preferably less than 20%.

[0037] Item 12. A solar cell or solar cell module according to one or more of Items 1 to 11, wherein the efficiency produced by the effect pigment and / or the effect pigment layer is reduced [W / m]. 2 The content should be less than 40%, preferably less than 30%, and most preferably less than 20%.

[0038] Item 13. A solar cell or solar cell module according to one or more of Items 1 to 12, wherein the external quantum efficiency is ≥0.6, preferably ≥0.8, in the wavelength region of 260 to 1200 nm.

[0039] Item 14. A solar cell or solar cell module according to one or more of Items 1 to 13, wherein the effect pigment is based on a sheet-like glass substrate, a sheet-like SiO2 substrate, or a sheet-like Al2O3 substrate.

[0040] Item 15. A solar cell or solar cell module according to one or more of Items 1 to 14, wherein the sheet-like substrate is coated with one or more layers of metal oxides and / or metal oxide hydrates of Ti, Sn, Si, Al, Zr and Zn.

[0041] Item 16. A solar cell or solar cell module according to one or more of Items 1 to 15, wherein the effect pigment is contained in a layer located on the outer surface of the solar cell, on or therein in any laminated material such as EVA (ethylene ethyl acetate film), TPU (thermoplastic polyurethane) or silicone, directly on the photoactive material of the solar cell or on a protective substrate covering the solar cell module.

[0042] Item 17. A solar cell or solar cell module according to one or more of Items 1 to 16, wherein the effect pigment is contained in a sol-gel based, polymer-based layer or in a glass frit-based layer located inside or outside the glass-facing layer.

[0043] Item 18. A solar cell or solar cell module according to one or more of Items 1 to 17, wherein, prior to assembling the solar cell module, the solar cell and the metal-based conductive components of the solar cell module are dark-colored and use a black or dark blue backplate.

[0044] Item 19. A solar cell or solar cell module according to one or more of Items 1 to 18, wherein a dark pattern is placed on top of the effect pigment layer, which covers bright areas such as the spaces between individual cells and busbars, conductive paths and solder joints, or wherein the metal-based conductive components of the solar cell or solar cell module are dark, or wherein a black or dark blue backplate is located on the back side of the solar cell or solar cell module.

[0045] Item 20. A method for preparing a solar cell or solar cell module according to Items 1 to 19, wherein a coating composition comprising an effect pigment, one or more binders such as organic or inorganic binders, and optional additives is applied to the solar cell or solar cell module, the effect pigment comprising a transparent or translucent sheet-like substrate coated with one or more layers of transparent or translucent material and optionally coated with a post-coating.

[0046] Project 21. The method of Project 20, wherein the coating composition is applied by screen printing, flexographic printing, gravure printing, offset printing, inkjet printing, other digital printing methods, slot die coating, spraying, dip coating, squeegee / blade coating, curtain coating, film transfer coating or aerosol spraying.

[0047] Project 22. According to the method of Projects 20 to 21, a dark pattern is placed on top of a coating composition containing effect pigments, which covers bright areas such as spaces between individual cells and busbars, conductive paths and solder joints.

[0048] Item 23. According to the methods of Items 20 to 22, the metal-based conductive component of the solar cell is dark-colored.

[0049] Item 24. The method according to Items 20 to 23, wherein a black or dark blue backsheet is applied to the back side of the solar cell or solar cell module.

[0050] The term "on or in the front radiating receiving side" means that the pigment-colored layer can cover the solar cell or solar cell module, or that the pigment-colored layer can be applied to the inside of the glass, or to a protective foil, or to an outer foil, and is applied on top of the finished solar cell or solar cell module. In other words, the pigment-colored layer is located within the visible portion of the solar cell or solar cell module. The pigment-colored layer can be applied by spraying, coating, printing, or laminating foil.

[0051] This invention provides a highly efficient material and method for coloring existing (single) solar cells and solar cell modules made of multiple electrically interconnected solar cells. This method offers great flexibility and enables a wide range of different colors, while maintaining low or negligible solar cell efficiency loss and high long-term stability. Furthermore, this invention provides a solution for achieving high color uniformity, wherein no busbars are present and no individual solar cells are visible within the solar cell module, while simultaneously achieving low or negligible solar cell efficiency loss.

[0052] Surprisingly, it has been found that the effect pigments according to the invention ideally provide sufficient color without significantly reducing the overall solar cell efficiency when printed on glass or Si or used in EVA films (ethylene ethyl acetate films). Long-term testing has shown a high level of stability. A 1000-degree damp heat test in a climate chamber (as described in http: / / sinovoltaics.com / learning-center / testing / damp-heat-test / ) showed that the long-term stability of the manufactured single-cell solar modules was not affected by the effect pigment layer directly printed on top of the solar cells in any binder. Since the direct contact between the effect pigment-containing layer and the solar cells is the most critical location in the installation of the solar modules, it can be assumed that there are no adverse effects at any point in the solar module stack.

[0053] The effect pigments reflect a portion of visible sunlight, but allow the desired light to pass through to generate energy. These effect pigments can even be oriented in a specific way, allowing for tuning of the angle for optimal efficiency and control over color and efficiency. The ability to easily apply effect pigments to existing solar cells or solar cell modules makes such application even more effective.

[0054] This invention therefore relates to the use of flake-like effect pigments in solar cells. Specifically, the invention relates to solar cells or solar cell modules comprising effect pigments consisting of a transparent or translucent flake-like substrate coated with one or more layers of transparent or translucent material. By using this invention, the visual appearance of solar cells and solar cell modules can be adapted to specific needs. The external visual appearance of objects containing solar cells, such as buildings, equipment, automobiles, etc., can be improved, and the transparency and reflectivity of the solar cells can be controlled. Additionally, when using a dark backsheet, the visibility of the cells and brightly colored busbars is avoided, and the busbars and connection points appear dark. Similarly, the invention can also be used to provide solar cells or solar cell modules with unusual colors to achieve special effects and designs, such as adding texture, meaning, for example, a shimmering effect on the panel, depending on the effect pigment used.

[0055] A key advantage of this invention is the ability to seamlessly integrate solar cells or solar cell modules into any surface by altering their appearance to a neutral, familiar look. It is possible to color solar cells or solar cell modules in a variety of colors, and it is not limited to rigid substrates such as glass or single-cell technologies. Furthermore, no complex solutions, such as additional layers in a stacked assembly, are necessarily required.

[0056] Furthermore, the cost of solar energy has not increased significantly because, unlike currently available technologies, the efficiency of solar cells or solar cell modules has not been greatly affected. A major drawback of currently available technologies is their impact on solar cell performance, where, under real-world conditions, the efficiency of solar cells drops from an initial performance of >15% to below 10%.

[0057] Surprisingly, by appropriately selecting the concentration of the effect pigments, these pigments exhibit the potential to uniformly color solar cells with minimal impact on cell efficiency. Surprisingly, this effect has been found, particularly with conventional effect pigments such as pearlescent pigments, interference pigments, and / or multilayer pigments. Since these effect pigments operate based on reflection in selected specific wavelength regions, the color effect can be selectively tuned, and the resulting efficiency can be directly correlated with the reflected portion of light. Typically, desired color effects can already be obtained at low reflectance at specific wavelengths. The performance can even be improved at dedicated wavelengths of 700 to 1100 nm as detected by some thin films—important for quantum efficiency. The long-term stability of the entire system has been tested and proven advantageous.

[0058] A coating composition comprising effect pigments (which comprise a transparent or translucent flake substrate coated with one or more layers of transparent or translucent material), a solvent system, an organic or inorganic binder system or a mixture thereof for fixing the effect pigments, and optionally one or more additives, is applied to the solar cell or solar cell module.

[0059] Because the effect pigments can be applied locally and flexibly to any surface, all different application methods can be used:

[0060] 1) An effect pigment coating may be applied to the exterior of a finished solar cell or solar cell module, on a protective substrate (glass or plastic) covering the solar cell or solar cell module, on or in any laminated material such as EVA (ethylene ethyl acetate film), TPU (thermoplastic polyurethane) or silicone, or directly on the photoactive material / solar cell.

[0061] 2) Effect pigment layers can be applied by spraying, coating, or various printing methods such as gravure printing, flexographic printing, offset printing, pad printing, preferably screen printing, (micro)spraying, dip coating, slot die coating, squeegee / squeegee coating, dispensing, laser-assisted transfer, curtain coating, film transfer coating, aerosol jetting, powder coating, inkjet printing, brushing, or similar methods.

[0062] 3) Apply to any surface typically colored with pigment, such as buildings, communication and transportation objects, such as cars, trains, trucks, trailers, hand equipment, ships, price tags, plastics, wearable items and household appliances or similar items.

[0063] 4) This invention can be applied to any type of solar cell technology, including amorphous, monocrystalline and polycrystalline silicon solar cells, CIGS, CdTe, III / V solar cells, II / VI solar cells, perovskite solar cells, organic solar cells and dye-sensitized solar cells, as well as solar cell modules made from single cells. Crystalline solar cells include cell structures such as Al-BSF, PERC, PERL, PERT, HIT, IBC, bifacial, or any other cell type based on crystalline silicon substrates.

[0064] 5) This invention can be used to seamlessly integrate solar cells into buildings (facades and roofs), portable and installed devices, motor vehicles (cars, motorcycles, scooters, trucks and the like) or other types of solar facilities, where the typical technical appearance of solar cells will change the typical appearance that people are used to, and long-term stability is necessary.

[0065] The effect pigment layer gives the front surface of the solar cell different colors, such as red, purple, and green. The effect pigment layer can contain effect pigment particles of different thicknesses and concentrations.

[0066] This invention provides the possibility of seamlessly integrating solar cells into any surface by changing the appearance to a neutral look that people are accustomed to. Advantageously, this invention enables the incorporation of solar cells into many types of surfaces, such as buildings, automobiles, handheld devices, or any other highly visible surface where seamless integration of solar cells is required without altering the optical appearance. To conceal the spaces between individual cells and busbars, conductive paths, and solder joints, a dark (solar cell blue or black) grid can be incorporated into any layer of the solar module to hide those areas, as long as the effect pigment layer is on top of it. To conceal the spaces between individual cells, a black or dark solar blue backing layer can be used behind the cells. This can be printed or can be a foil.

[0067] Advantageously, the pigment-colored coating of the present invention can also be used as an anti-reflective coating.

[0068] The effect pigments used according to the present invention are preferably transparent or at least translucent. The effect pigments used in the present invention preferably display green. However, other colors such as blue, gray, white, purple, red, orange, and black are also suitable. Other colors or mixtures thereof can be used to produce specific colors and hues. The effect pigments can also produce metallic effects, such as, but not limited to, silver, platinum, gold, copper, and many other metals. Mixtures of different colors can also be used to produce printed images / pictures.

[0069] The effect pigments and / or effect pigment layers of the present invention preferably selectively reflect 1-100%, more preferably 5-40%, of the visible light of the solar spectrum, while a reflectance of 5% in the range of, for example, 450-550 nm is sufficient to obtain a strong green impression of a solar cell that is otherwise optically blue.

[0070] The effect pigments and / or the effect pigment layers of the present invention preferably have a transparency of at least 30%, preferably >80%, for radiation associated with a particular solar cell or solar cell module, preferably for radiation in the range of 260 to 1200 nm.

[0071] Preferably, the effect pigment and / or the effect pigment layer have a reflectance level of 1% to 40%, preferably <30%, for radiation in the range of 260 to 1200 nm.

[0072] In particular, the effect pigment and / or the effect pigment layer have a reflectance level of <20%, preferably <10%, for radiation in the range of 260 to 1200 nm.

[0073] In addition to their specific colors, the effect pigment layers exhibit a high level (at least 30%, preferably >80%) of transparency for radiation associated with a particular solar cell, preferably for radiation in the 260 to 1200 nm range, and preferably exhibit a reflectance level of about 5 to 40%, preferably less than 10%. In the 260 to 1200 nm wavelength region, the internal and external quantum efficiencies are preferably ≥60% (≥0.6), preferably ≥70% (≥0.7), and preferably (≥0.8) ≥80%. In the 260 to 1200 nm wavelength region, at a reflectance of 40% and preferably >80%, the internal and external quantum efficiencies are preferably 60%. The quantum efficiency describes the amount of photons used for electricity generation. The external quantum efficiency (EQE) describes the wavelength selectivity relationship of the total amount of photons illuminating the solar cell, related to the amount of photons absorbed by the solar cell and effectively converted into electricity. The internal quantum efficiency (IQE) describes the relationship of the amount of photons reaching the solar cell and converted into electricity. In the case of the present invention, the difference between the internal and external quantum efficiencies can be described as follows:

[0074] EQE = IQE - Photons reflected by the effect pigment layer

[0075] Therefore, the high levels of both IQE and EQE indicate a limited impact of the effect pigments on the performance of the solar cell. The relative current loss [A / m] generated by the effect pigments and / or the effect pigment layer... 2 The efficiency is less than 40%, preferably less than 30%, and most preferably less than 20%. Therefore, the efficiency of the effect pigment and / or the effect pigment layer is reduced [W / m]. 2 The content should be less than 40%, preferably less than 30%, and most preferably less than 20%.

[0076] The effects of pigments and layers on c-Si solar cells were evaluated using reflectance data. The reflectance data was used to estimate the maximum power absorption / maximum photocurrent generation of the treated cells. The measurements and calculations of reflection and transmission were performed using methods known to those skilled in the art and as further described in the experimental section.

[0077] The reference with TPU-based encapsulation exhibits 90% typical EQE over a wide wavelength range. The effect pigment mixture according to the invention, which results in a white / gray appearance for solar cells, shows a decrease in quantum efficiency of about 7% in the IR region, while the green effect pigment according to the invention, based on coated glass sheets, shows an average decrease and even an increase in quantum efficiency of less than 5% in the IR region.

[0078] The effect pigments used according to the present invention preferably have a flake-like substrate comprising at least one coating containing a metal oxide, a metal oxide hydrate, or a mixture thereof. Preferably, the effect pigments consist of a transparent or translucent colorless flake-like substrate already coated with one or more layers of a transparent or translucent colorless material. Pearlescent pigments, interference pigments, and / or multilayer pigments are preferred. When a post-coating of an organic coating and / or an inorganic coating is used as the final layer of the effect pigment, the long-term stability of the effect pigment can preferably be improved, as described in WO 2011 / 095326 A1 and hereinafter.

[0079] Suitable substrates for the effect pigments are, for example, all known coated or uncoated flake substrates, preferably transparent or translucent, and preferably colorless flakes. Suitable substrates include, for example, pisilicates, particularly synthetic or natural mica, glass flakes, SiO2 flakes, Al2O3 flakes, TiO2 flakes, liquid crystal polymers (LCPs), holographic pigments, BiOCl flakes, or mixtures of these flakes. According to the invention, aluminum flakes with a dielectric coating can also be used at low concentrations to obtain very high hiding power for the active photovoltaic layer.

[0080] The glass sheet may be composed of all glass types known to those skilled in the art, such as A-glass, E-glass, C-glass, ECR glass, recycled glass, window glass, borosilicate glass, etc. It is composed of glass, laboratory glass, or optical glass. The refractive index of the glass sheet is preferably 1.45-1.80, particularly 1.50-1.70. Particularly preferred glass sheets are composed of A-glass, C-glass, E-glass, ECR glass, quartz glass, and borosilicate glass.

[0081] Preferred materials include coated or uncoated synthetic or natural mica flakes, SiO2 flakes, Al2O3 flakes, and glass flakes, particularly C glass, ECR glass, or calcium aluminum borosilicate glass flakes. In particular, effect pigments based on calcium aluminum borosilicate glass are preferred. In one variant of the invention, Al2O3 flakes are preferred.

[0082] The substrate typically has a thickness between 0.01 and 5 μm, particularly between 0.05 and 4.5 μm, and especially preferably between 0.1 and 1 μm. The length or width dimensions are typically between 1 and 500 μm, preferably between 1 and 200 μm, and especially between 5 and 125 μm. They typically have an aspect ratio (ratio of average diameter to average particle thickness) of 2:1 to 25,000:1, preferably between 3:1 and 1000:1, and especially between 6:1 and 250:1. The dimensions of the sheet-like substrate are also applicable in principle to the coated effect pigments used according to the invention, since the additional coating is typically in the range of only a few hundred nanometers and therefore does not significantly affect the thickness or length or width (particle size) of the effect pigment.

[0083] 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 following standard procedures using Malvern Mastersizer 2000, Beckman Coulter, Microtrac, etc., are preferred. Additionally, other techniques such as SEM (scanning electron microscopy) images can be used.

[0084] In a preferred embodiment, the substrate is coated with one or more transparent or translucent layers comprising metal oxides, metal oxide hydrates, metal hydroxides, low-oxide metals, metal fluorides, metal nitrides, metal oxynitrides, or mixtures of these materials. Preferably, the substrate is partially or completely encapsulated by these layers.

[0085] Furthermore, multilayer structures comprising high- and low-refractive-index layers may also exist, wherein the high- and low-refractive-index layers are preferably alternating. Particularly preferred are layer packages 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 packages may have been applied to the substrate. The order of the high- and low-refractive-index layers may be matched with the substrate to include the substrate in the multilayer structure.

[0086] Particularly preferred are metal oxides, metal oxide hydrates, or mixtures thereof, especially those containing the elements Ti, Sn, Si, Al, Zr, and Zn, particularly Ti, Sn, and Si. The oxides and / or oxide hydrates may be present in a single layer or in separate layers. In particular, rutile-modified or anatase-modified (preferably rutile-modified) titanium dioxide is used. To convert titanium dioxide to the rutile-modified form, a tin dioxide layer is preferably applied beneath the titanium dioxide layer. Preferred multilayer coatings comprise alternating high and low refractive index layers, preferably, for example, TiO2-SiO2-TiO2.

[0087] Preferably, a layer of metal oxide, hydroxide, and / or oxide hydrate is applied using a known wet chemical method, wherein a wet chemical coating method developed for preparing effect pigments can be used, resulting in the encapsulation of the substrate. Following wet chemical application, the coated product is subsequently separated, washed, dried, and preferably calcined.

[0088] The thickness of a single layer is typically 10 to 1000 nm, preferably 15 to 800 nm, especially 20 to 600 nm, and particularly 20 to 200 nm.

[0089] To enhance light, temperature, water, and climate stability, the effect pigments may undergo post-coating or post-treatment. The post-coating may be an organic coating and / or an inorganic coating as a final layer or multiple layers. The post-coating preferably comprises a metal oxide layer containing one or more elements Al, Si, Zr, Ce, or mixtures or mixed phases thereof. Furthermore, organic or combined organic / inorganic post-coatings are possible. Silanes and / or organofunctional silanes may also be used alone or in combination with metal oxides. Suitable post-coating or post-treatment methods are, for example, those described in DE 22 15191, DE-A 31 51 354, DE-A 32 35017 or DE-A 33 34 598, EP 0090259, EP 0 634 459, WO 99 / 57204, WO 96 / 32446, WO 99 / 57204, US5,759,255, US5,571,851, WO 01 / 92425, WO 2011 / 095326 or other methods known to those skilled in the art.

[0090] The effect pigments that can be used in this invention are, for example, those marketed under the trade name and Lumina Commercially available interference or pearlescent pigments are provided. Other commercially available effect pigments can also be used. In particular, [the following can be used]... and pigment.

[0091] For application in solar cells, the effect pigment is incorporated into an application medium, preferably a transparent coating formulation, and then applied to the solar cell.

[0092] The application medium can be selected from, for example, water-based varnishes, solvent-based varnishes, UV-curable varnishes and electron beam-curable varnishes, ceramic glazes, and sol-gel based components.

[0093] The effect pigment may be contained in a layer located on the outer surface of the solar cell, on or within any laminate such as EVA (ethylene ethyl acetate film), TPU (thermoplastic polyurethane), or silicone, directly on the photoactive material of the solar cell, or on a protective substrate covering the solar cell module. The effect pigment may also be contained in a sol-gel based, polymer-based, or glass-based layer, either on the inside or outside of the glass-facing layer.

[0094] According to the invention, sol-gel-based or polymer-based antireflective layers, applied to the inside or outside of a glass layer, can also be used to achieve effect pigments on any solar cell or solar cell module. One exemplary approach is to incorporate the effect pigments into a silica-based sol-gel solution prepared by hydrolyzing, for example, tetraethyl orthosilicate and subsequently polycondensing the solution on the substrate. Another exemplary approach is to form a glass-like layer on the front glass by mixing a glass frit commonly used in the printing industry with the effect pigments, and subsequently melting the resulting mixture of glass particles. The antireflective layer can also be mixed with a polymer during a high-temperature step to create pores that improve antireflective properties, or it can be microstructured. Similar methods of producing antireflective layers known industrially can also be used to incorporate the effect pigments according to the invention.

[0095] The application medium of this invention may also contain a mixture of different effect pigments, as in many cases, using at least two different effect pigments allows for the achievement of special effects. In this case, the effect pigments can be mixed in any proportion; however, the total content of all effect pigments in the application medium should not exceed 60% by weight.

[0096] The concentration of the effect pigment or mixture of effect pigments is preferably in the range of 1-40% by weight, more preferably 1-25% by weight, based on the total weight of the solid portion of the application medium. Preferably, the amount of effect pigment is in the range of 1-15% by weight, particularly 2-12%, and especially 3-8% by weight.

[0097] Effect pigments in the film in grams per cubic meter 2 The quantity in units is limited by the film thickness. For example, a 20 μm thick film containing 1% effect pigment in a binder-based formulation will translate to approximately 0.4 g effect pigment / m. 2 A 100μm thick film containing 12% effect pigment will be converted into approximately 18g of effect pigment / m. 2 Therefore, every m 2 The typical range for effect pigments on treated solar surfaces is 0.1 g / m³. 2 (For thin films (1 μm) and low concentrations) up to 75 g / m 2(For high concentrations in thick films (200 μm)). The practical range of this invention is 0.4-30 g effect pigment / m 2 Preferred concentration: 1-25g / m 2 Especially preferred is 1-16g / m 2 Within the range.

[0098] Typically, a typical medium is prepared by mixing one or more effect pigments with a selection of commercially available, ready-to-use varnishes. Specific varnishes can also be manufactured to meet any stringent requirements.

[0099] A typical varnish contains at least one or more binders and solvents or mixtures of solvents. In addition, the varnish may contain other additives such as defoamers, anti-sagging agents, dispersants, leveling agents, scratch-resistant additives, substrate wetting agents, coupling agents, corrosion inhibitors, rheological modifiers, fire redundant agents, stabilizers, catalysts, odor masking agents, and colorants.

[0100] Typical application media of the present invention contain effect pigments, binders, and solvents as described, and may also contain other additives: defoamers, anti-sagging agents, dispersants, leveling agents, scratch-resistant agents, substrate wetting agents, coupling agents, corrosion inhibitors, rheological modifiers, flame retardants, stabilizers, catalysts, odor masking agents, etc. The application media may also contain other colorants.

[0101] The application medium is typically prepared by initially introducing one or more effect pigments and then uniformly mixing them with binders, solvents, and any additives.

[0102] The adhesives that can be used are adhesives or adhesive systems commonly used in printing processes, such as water-based or solvent-based adhesives based on nitrocellulose, polyamide, acrylate, polyvinyl butyral, PVC, or PUR, or suitable mixtures thereof. Two-component systems can be used.

[0103] Another option is a ceramic glaze (frit / sintering mixture) mixed with the effect pigments of the present invention. To avoid hindering the efficiency of the invention, the ceramic sintering material and flux can be cured in a transparent and colorless manner.

[0104] Preferably, the adhesive is transparent to visible light, provides good adhesion to solar cells or laminations or scratch-resistant / protective layers (depending on when applied), good environmental stability, and, if not used as a final layer, provides good wetting and adhesion to subsequent layers.

[0105] In addition to water, organic solvents can be used, such as branched or unbranched alcohols, aromatic compounds, or alkyl esters, such as ethanol, 1-methoxypropanol, 1-ethoxy-2-propanol, ethyl acetate, butyl acetate, toluene, or mixtures containing these substances. However, if radiation-curing adhesive systems, such as UV-curing adhesive systems, are used, the corresponding colored coating formulations can also have low solvent content or be completely solvent-free.

[0106] In addition to the binder or binder system and, where appropriate, one or more solvents, the coating vehicle may contain various additives, colorants, and / or auxiliaries in addition to their respective effect pigments.

[0107] Suitable additives include UV stabilizers, inhibitors, flame retardants, lubricants, dispersants, redispersants, defoamers, flow control agents, film-forming agents, adhesion promoters, drying accelerators, drying retarders, photoinitiators, etc. The respective coating carriers preferably contain all necessary liquid additives to ensure that the effects of the invention are not weakened or otherwise impaired by additional solids. Therefore, it is particularly preferred that the finished colored coating inks contain neither (soluble) dyes nor any other coloring pigments or solid fillers other than the effect pigments necessary according to the invention.

[0108] The pigment-colored coating formulation can then be applied by various methods, such as spraying, coating, or printing, for example by screen printing, flexographic printing, gravure printing, offset printing, inkjet printing, other digital printing methods, slot die coating, spraying, dip coating, squeegee / blade coating, curtain coating, film transfer coating, and aerosol spraying. Screen printing is preferred to achieve the best trade-off between appearance and minimal performance loss, and spraying is preferred to achieve the best appearance with slightly higher power loss.

[0109] The dry layer thickness is in the range of 0.1μm-1mm, preferably 0.5μm-200μm, more preferably 1μm-50μm, and especially in the range of 1μm-10μm.

[0110] The concentration of effect pigments in the dried film is about 1-20% based on the total weight of the film, preferably 2-10%, and especially 2-6%. For automotive applications, the amount of pigment can be even higher (1-40%, preferably 1-25%). Preferably, the amount of effect pigment is between 0.1 and 75 g / m³. 2 Within the range.

[0111] Coating media containing effect pigments according to the invention can be applied to any desired solar cell, such as amorphous, monocrystalline and polycrystalline silicon solar cells, CIGS, CdTe, III / V solar cells, II / VI solar cells, perovskite solar cells, organic solar cells and dye-sensitized solar cells, as well as solar cell modules made from single cells. Crystalline solar cells include cell structures such as Al-BSF, PERC, PERL, PERT, HIT, IBC, bifacial or any other cell type based on a crystalline silicon substrate.

[0112] The effect pigment can be applied to the exterior of a finished solar cell or solar cell module, on a protective substrate (glass or plastic) covering the module, on or within any laminated material such as EVA, TPU, or silicone, or directly on the photoactive material / solar cell. It is preferred to apply the printing to EVA or to the finished solar cell or solar cell module.

[0113] Another possibility for application to solar cells or solar cell modular units is the use of a (self-adhesive) foil containing the effect pigment, which can be fixed to glass and other surfaces. This can also be applied to any existing facility containing solar cell modules or small solar cell modules or even a single cell in handheld devices, transport vehicles, buildings, or the like.

[0114] A particular advantage of this invention is that it is now possible to seamlessly integrate solar cells into buildings (facades and roofs), portable and installed devices, motor vehicles (cars, motorcycles, scooters, trucks, and the like), or other types of solar installations, where the typical technical appearance of solar cells will be altered from what people are accustomed to. Advantageously, for use in motor vehicles, the effect pigments can be applied within the vehicle's transparent coating. Furthermore, this improvement is achieved without a significant loss of efficiency.

[0115] To achieve a completely uniform appearance for commonly used silicon solar cells or solar cell modules, the solar cells and the metal-based conductive components of the solar cell modules (the H-shaped grid consisting of the main vertical connectors—so-called busbars; and the horizontal current collectors—so-called fingers; the connectors and solder between the cells) should be dark before the effect pigment is applied. Possible ways to "darken" the metal components of silicon solar cells or modules with H-shaped grid patterns that are otherwise white are to cover the metal strips with black polymer foil or to brush the metal components with black paint. In the case of printed silver H-shaped grids, the silver can be blackened directly by forming a thin layer of silver sulfide (e.g., by treatment with H₂S) or by plating and oxidizing copper. In the case of plated metal grids, 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 other similar substances. When using novel metallization schemes (e.g., smart line technology), according to the invention, blackened lines or lines with microstructures that reduce reflectivity can also be used to give the metal grid a dark appearance. If a black or dark sun blue backplate is used as the module background, a very uniform appearance can be achieved throughout the module, even when viewed from a very close distance.

[0116] This invention can also lead to improved long-term stability of solar cells and solar cell modules because the effect pigments can partially block or at least prevent water vapor from passing through the flexible plastic foil, thus acting as an oxygen and water vapor barrier. A major drawback of many solar cells made of II / VI or III / V materials, as well as organic materials, is that moisture reaches the surface of the solar cell and causes photo-oxidation of the active material.

[0117] Additionally, the effect pigments can help improve the lifespan of solar cells or solar cell modules due to their absorption of UV light. The absorption in the effect pigment layer results in less damage to the organic encapsulation, and therefore less UV absorber must be used in these encapsulants, and reduces yellowing caused by the photo-oxidation of the polymer. For this purpose, the use of stabilized pigments as described above is essential. Detailed Implementation

[0118] Example

[0119] Example 1 ：

[0120] c-Si solar cells (CZ) are coated with different layers containing different effect pigments, different concentrations of effect pigments, and / or mixtures of effect pigments. The layers containing effect pigments give the surface appearance of the encapsulated sheet different colors, such as green or purple.

[0121] For example, using a manual platform screen printing machine, the product containing Proell Aqua Jet FGL M 093 varnish (95.5%) can be printed. Green (3%) and Proell Defoamer L36459 (1.5%) inks were printed onto a standard c-Si panel. A mesh from Sefar, PET 1500 54 / 137-64W (mesh parameters: 137 l / inch, 115 μm mesh opening, and 64 μm line diameter), was used. A manual squeegee with a Shore hardness of 75° was used for printing. The layer was dried at room temperature under ambient conditions.

[0122] Table 1 lists the additional effect pigments and their concentrations.

[0123] Table 1

[0124]

[0125] The impact of the pigment layer on c-Si solar cells was evaluated using reflectance measurements.

[0126] Estimate the maximum power absorption / maximum photocurrent generation of the battery being processed using reflection data:

[0127] Spectral reflectance was recorded within a wavelength interval between 280 nm and 1200 nm.

[0128] The transmittance of the cell is artificially set to zero (because this is also expected for the actual use conditions of Si solar cells, which contain sintered and alloyed aluminum powder paste that almost completely covers the back side, which typically forms the back electrode of such devices).

[0129] As is customary, short-wavelength light is completely absorbed by the battery itself.

[0130] Calculate the absorption of light by the entire system

[0131] Absorption in the pigment layer, ignoring SiNx and Al (because they are unknown).

[0132] Power absorption was converted into the maximum achievable photocurrent based on the AM1.5G spectrum (according to IEC 60904-3, 2nd edition, which is equivalent to ASTM G173-03). For this purpose, the aforementioned reference spectrum was obtained, and the irradiance was recalculated using interpolated spectra, with a single nanometer resolution step size applied for the wavelength region from 280 nm to 1200 nm. The integration of the interpolated spectrum yielded 835.998 W / m². 2 The total irradiance is 836.19 W / m². 2The original reference spectrum has the same wavelength range as the interpolated spectrum, which matches the integral very well. The difference between the original spectrum and the interpolated spectrum is 0.2‰.

[0133] PTFE (Polydioxanone) as a reflectance standard

[0134] Cary 5000 (UV / ViS / NIR); Agilent

[0135] All batteries (if applicable) underwent 4 tests.

[0136] The battery undergoes a reflectivity measurement.

[0137] Inspect the measuring device by using a 'reference sample'

[0138] The incident light is perpendicular to the surface of the battery.

[0139] Reflectivity is measured from the front side of the battery.

[0140] -Front side: In this context, by definition, by SiN x The covered surface of the solar cell is considered the so-called "front side"; it is colored, in contrast to the all-Al electrode.

[0141] - Repeat the measurement 3 times (4 measurements in total)

[0142] The irradiated surface covered a large area fraction with a diameter of up to 1 cm.

[0143] Therefore, reflectivity data is an average integral that includes both metallized and non-metallized surfaces.

[0144] The measured data are averaged, and the average value is used for further consideration:

[0145] The average reflectivity of the battery is taken as the average value.

[0146] Estimate standard deviation and variance

[0147] Estimate the error range of T based on a 99% probability (confidence interval).

[0148] Using PTFE standard as a reference

[0149] During the measurement process, the sample bundle was not covered or sealed by the light-absorbing cap so as not to unintentionally damage or destroy the fragile silicon solar cell.

[0150] The results are summarized in Table 2.

[0151] Table 2

[0152]

[0153] Example 2:

[0154] Small solar modules were fabricated as follows: a layer containing effect pigments according to the invention in a water-based resin was directly printed onto a commercially available AI-BSF solar cell. The modules were then brought into contact by hand soldering and encapsulated between a glass plate and a tedlar backsheet using thermoplastic polyurethane (TPU) or ethyl vinyl acetate (EVA). Efficiency was measured in a standardized setup at AM1.5.

[0155] Although the uncoated reference module showed an efficiency of up to 17.6%, none of the tested small solar modules showed an efficiency drop of more than 10% (relatively). Even the white-looking module showed an effective efficiency of 16% due to the selective reflection of light caused by the effect pigments.

[0156] Example 3:

[0157] The small solar module is prepared as follows: a layer containing effect pigments according to the invention in a water-based glass / glass frit mixture is directly screen-printed onto commercially available low-iron glass for solar modules, and then tempered in an oven at 600°C-680°C. In a second step, a grid with colored ceramic colors is printed on top of the layer in a specific design to cover bright areas such as the spaces between individual cells and busbars, conductive paths, and solder joints.

[0158] The module was prepared using the following steps, and then fused together.

[0159] - The glass panel is covered with a dark blue backing made of thermoplastic polyurethane (TPU) or ethyl vinyl acetate (EVA). In this case, a black multilayer backing made of Dymat (Bk PYE SPV-L) is used.

[0160] - Place the battery and manually connect it to the contact point.

[0161] - Place a second sheet made of thermoplastic polyurethane (TPU) or ethyl vinyl acetate (EVA) on top of the battery.

[0162] -At the top, place the stained glass panel in such a way that all remaining bright areas are covered by dark grids.

[0163] - The module is heated in a vacuum oven at 100°C to seal the module.

[0164] Efficiency was measured in a standardized apparatus under AM1.5 conditions.

[0165] Although the uncoated reference module showed an efficiency of up to 17.6%, none of the tested small solar modules showed an efficiency drop of more than 20% (relatively). Even the white-looking module showed an effective efficiency of 15.1% due to the selective reflection of light caused by the effect pigments.

[0166] Example 4:

[0167] Using a manual platform screen printing machine, a translucent organic solar cell with an integrated blue LED (powered by the organic solar cell) was coated with a varnish containing 95.5% Proell Aqua Jet FGL M 093. Printing was done with Green (3%) and Proell Defoamer L36459 (1.5%) inks. A mesh from Sefar, PET 1500 54 / 137-64W (mesh parameters: 137 l / inch, 115 μm mesh opening, and 64 μm line diameter), was used. A manual squeegee with a Shore hardness of 75° was used for printing. The layer was dried at room temperature under ambient conditions. The brightness of the LEDs integrated into the organic solar cell is based on the current they generate and can therefore be used to measure efficiency. The LEDs exhibit the same brightness when illuminated from either the printed or unprinted side; therefore, the effect of the effect pigment coating on the current and efficiency of the organic solar cell is negligible.

[0168] Example 5 ：

[0169] Spraying solar cells with paint containing effect pigments

[0170] Standard solar cells are coated using conventional equipment.

[0171] The pearlescent pigment used, in this case a green interference pigment, was stirred in a commercially available 2K repair varnish (MIPA CC4 2K Klarlack) from MIPA at a concentration of 1.13% based on the formulation. The coating was prepared according to the supplier's recommendations and adjusted to an application viscosity of 70-75 mPas at 1000 1 / s.

[0172] Use the following effect pigments:

[0173] 9231SW

[0174] 9235SW

[0175] 97235SW

[0176] Green

[0177] Stellar Green SW

[0178] To apply the prepared coating to the solar cells, an automated spraying machine, Oerter APL4.6, was used. In this case, the coating was applied using a 1.4 mm nozzle in two consecutive cycles. The coating was allowed to dry at room temperature for 10 minutes before being dried at 70°C for 60 minutes. Finally, a dry film thickness of approximately 40 μm was obtained.

[0179] The properties of the green interference pigment are clearly visible on the solar cell panel; the green color is visible at certain angles but not at others.

[0180] To further characterize the panel and the effect of the effect pigments used on the panel efficiency, reflectivity was measured on the coated front side of the cell. Therefore, an Agilent Cary 5000 (UV / VIS / NIR) solar cell was used. As a reference, an uncoated standard solar cell was used. With this setup, it was determined that, depending on the green interference pigments used, the relative loss of achievable current was only 4.5% compared to the uncoated solar cell. StellarGreen SW) and 6.7% ( Between 9235SW).

Claims

1. Solar cell or solar cell module comprising at least one layer comprising at least one effect pigment on or in the front radiation-receiving side of the solar cell or solar cell module, the effect pigment consisting of a transparent or translucent flaky substrate coated with one or more layers of a transparent or translucent material and optionally with a back coating, wherein the effect pigment and / or the at least one layer comprising at least one effect pigment selectively reflects 1-100% of the visible light of the solar spectrum; wherein the effect pigment is based on a flaky substrate selected from synthetic or natural mica, glass flakes, Si02 flakes, AI2O3 flakes, Ti02 flakes, liquid crystal polymers, holographic pigments, BiOCI flakes, aluminum flakes, or mixtures of said flakes; wherein the substrate is coated with one or more transparent or translucent layers comprising metal oxides, metal oxide hydrates, metal hydroxides, metal suboxides, metal fluorides, metal nitrides, metal oxynitrides or mixtures of these materials.

2. Solar cell or solar cell module according to claim 1, wherein the effect pigment and / or the effect pigment layer selectively reflects 5-40% of the visible light of the solar spectrum.

3. Solar cell or solar cell module according to claim 1, wherein the effect pigment and / or the effect pigment layer selectively reflects 1-40% of the visible light of the solar spectrum.

4. Solar cell or solar cell module according to claim 1, wherein the effect pigment and / or the effect pigment layer has a transparency of at least 30% for radiation in the range of 260 to 1200 nm.

5. Solar cell or solar cell module according to claim 4, wherein the effect pigment and / or the effect pigment layer has a transparency of > 80% for radiation in the range of 260 to 1200 nm.

6. Solar cell or solar cell module according to claim 1, wherein the effect pigment and / or the effect pigment layer has a reflection level of 1 to 40% for radiation in the range of 260 to 1200 nm.

7. Solar cell or solar cell module according to claim 6, wherein the effect pigment and / or the effect pigment layer has a reflection level of < 30% for radiation in the range of 260 to 1200 nm.

8. Solar cell or solar cell module according to claim 6, wherein the effect pigment and / or the effect pigment layer has a reflection level of < 20% for radiation in the range of 260 to 1200 nm.

9. Solar cell or solar cell module according to claim 6, wherein the effect pigment and / or the effect pigment layer has a reflection level of < 10% for radiation in the range of 260 to 1200 nm.

10. Solar cell or solar cell module according to any one of claims 1 to 9, wherein the effect pigment is selected from the group consisting of pearl pigments, interference pigments and multilayer pigments.

11. The solar cell or solar cell module according to any one of claims 1 to 9, wherein the amount of the effect pigment in the application medium is in the range of 1-40 wt.-%, based on the solid fraction of the application medium.

12. The solar cell or solar cell module according to claim 11, wherein the amount of the effect pigment in the application medium is in the range of 1-15 wt.-%, based on the solid fraction of the application medium.

13. The solar cell or solar cell module according to any one of claims 1 to 9, wherein the amount of the effect pigment is in the range of 0.1 to 75 g / m2. 2 of the effect pigment is in the range of 0.1 to 75 g / m2.

14. The solar cell or solar cell module according to any one of claims 1 to 9, wherein the thickness of the at least one layer comprising at least one effect pigment is in the range of 1 to 200 pm.

15. The solar cell or solar cell module according to any one of claims 1 to 9, wherein the effect pigment has a post-coat as the last layer, which is an organic coating and / or an inorganic coating.

16. The solar cell or solar cell module according to any one of claims 1 to 9, wherein the internal quantum efficiency is > 0.7 in the region of wavelengths from 260 to 1200 nm.

17. The solar cell or solar cell module according to claim 16, wherein the internal quantum efficiency is > 0.8 in the region of wavelengths from 260 to 1200 nm.

18. The solar cell or solar cell module according to any one of claims 1 to 9, wherein the effect pigment and / or the at least one layer comprising at least one effect pigment produces a relative current loss [A / m2] of less than 40%. 20 2 ] is less than 40%.

19. The solar cell or solar cell module according to claim 18, wherein the effect pigment and / or the at least one layer comprising at least one effect pigment produces a relative current loss [A / m2] of less than 30%.

20. 2 ] 20. The solar cell or solar cell module of claim 18, wherein the effect pigment and / or the at least one layer comprising at least one effect pigment produces a relative current loss [A / m2] of less than 20%. 2 ] is less than 20%.

21. The solar cell or solar cell module according to any one of claims 1 to 9, wherein the effect pigment and / or the at least one layer comprising at least one effect pigment produces an efficiency reduction [W / m2] of less than 40%. 20 2 ] is less than 40%.

22. The solar cell or solar cell module according to claim 21, wherein the effect pigment and / or the at least one layer comprising at least one effect pigment produces an efficiency reduction [W / m2] of less than 30%.

23. 2 ] 23. The solar cell or solar cell module according to claim 21, wherein the effect pigment and / or the at least one layer comprising at least one effect pigment produces an efficiency reduction [W / m2] of less than 20%. 25 2 ] is less than 20%.

24. The solar cell or solar cell module according to any one of claims 1 to 9, wherein the external quantum efficiency is > 0.6 in the region of wavelengths from 260 to 1200 nm.

25. The solar cell or solar cell module according to claim 24, wherein the external quantum efficiency is > 0.8 in the region of wavelengths from 260 to 1200 nm.

26. The solar cell or solar cell module according to any one of claims 1 to 9, wherein the effect pigment is based on a flaky glass substrate or a flaky SiO2 substrate or a flaky Al2O3 substrate.

27. The solar cell or solar cell module according to any one of claims 1 to 9, wherein the flaky substrate is coated with one or more layers of metal oxides and / or metal oxide hydrates of Ti, Sn, Si, Al, Zr and Zn.

28. The solar cell or solar cell module of any of claims 1 to 9, wherein the effect pigment is contained in a layer located on the outer surface of the solar cell, on any lamination material or in it, directly on the photoactive material of the solar cell or on a protective substrate covering the solar cell module.

29. The solar cell or solar cell module according to claim 28, wherein the lamination material is an ethyl vinyl acetate film, a thermoplastic polyurethane or a silicone.

30. The solar cell or solar cell module according to any one of claims 1 to 9, wherein the effect pigment is contained in a sol-gel based, polymer based layer or in a layer based on a glass frit, which is located inside or outside the glass facing layer.

31. The solar cell or solar cell module according to any one of claims 1 to 9, wherein the solar cell and the metal-based conductive parts of the solar cell module are dark before assembling the solar cell module and a black or dark blue backsheet is used.

32. The solar cell or solar cell module according to any one of claims 1 to 9, wherein a dark pattern is placed on top of the at least one layer comprising at least one effect pigment, which covers bright areas, or wherein the metal based conductive parts of the solar cell or solar cell module are dark, or wherein a black or dark blue backsheet is located on the backside of the solar cell or solar cell module.

33. The solar cell or solar cell module according to claim 32, wherein the bright areas are the spaces between individual cells and busbars, conductive paths and solder points.

34. A method of making a solar cell or solar cell module according to any one of claims 1 to 33, wherein a coating composition comprising an effect pigment, one or more binders and optionally additives is applied to the solar cell or solar cell module, the effect pigment comprising a transparent or translucent flaky substrate coated with one or more layers of transparent or translucent material and optionally a post-coat layer.

35. The method according to claim 34, wherein the binder is an organic or inorganic binder.

36. The method according to claim 34, wherein the coating composition is applied by screen printing, flexographic printing, gravure printing, lithographic printing, inkjet printing, other digital printing methods, slot die coating, spray coating, dip coating, blade / doctor blade coating, curtain coating, film transfer coating or aerosol jet.

37. The method according to any one of claims 34 to 36, wherein a dark pattern is placed on top of the coating composition comprising effect pigment, which covers bright areas.

38. The method according to claim 37, wherein the bright areas are the spaces between individual cells and busbars, conductive paths and solder points.

39. The method according to any one of claims 34 to 36, wherein the metal based conductive parts of the solar cell are dark.

40. The method according to any one of claims 34 to 36, wherein a black or dark blue backsheet is applied on the backside of the solar cell or solar cell module.

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