Photovoltaic composite pane with an aerogel layer

Abstract

Composite pane, comprising an outer pane (1) and an inner pane (2) which are connected to one another via an intermediate layer (3), wherein at least one photovoltaic component (4) is embedded in the intermediate layer (3) and wherein the intermediate layer (3) contains an aerogel layer (5) which has a smaller distance from the inner pane (2) than the at least one photovoltaic component (4).

Description

[0001] The invention relates to a composite pane equipped with at least one photovoltaic component and an aerogel layer.

[0002] It is well known that glazing can be equipped with photovoltaic components to generate electrical energy. For example, WO03028114A2 discloses insulating glazing with a photovoltaic module. Insulating glazing is used primarily as building glazing.

[0003] Glazing with photovoltaic components can also be of interest in the automotive sector, particularly as vehicle roof windows. The photovoltaic components can be used, for example, to charge the on-board battery or power electrical consumers. This is becoming increasingly important, especially in connection with electric vehicles. EP1036683A2 discloses a vehicle roof window designed as a single pane of glass and equipped with a solar cell assembly on the interior side.

[0004] Vehicle roof windows are often designed as composite panes, comprising an outer pane and an inner pane joined together by a thermoplastic intermediate layer. In such composite panes, the photovoltaic components can be embedded in the intermediate layer, as is known, for example, from WO2013182398A1 and WO2013182399A1.

[0005] To improve thermal comfort in the vehicle interior, vehicle roof windows are often provided with IR-reflective coatings. These are, in particular, so-called LowE coatings with reflective properties in the mid-IR range on the interior-facing surface of the inner pane and / or so-called sun protection coatings with reflective properties in the near-IR range on the interior-facing surface of the outer pane. The LowE coating is intended to reduce thermal radiation from the heated composite pane into the interior in summer and to reduce the radiation of thermal energy from the interior in winter. The sun protection coating serves to reflect infrared components of solar radiation. For example, see WO2019110172A1, which discloses a vehicle roof window with both coatings.

[0006] A photovoltaic component absorbs visible light and / or infrared radiation to convert it into electrical energy. This causes the photovoltaic component to heat up considerably, creating additional thermal stress. Furthermore, a solar control coating is often omitted, especially if the photovoltaic component is also sensitive to the IR range, which leads to additional heating of the photovoltaic component. This can severely impair thermal comfort in the interior because the total solar energy radiated (comprising the direct solar energy and the indirect solar energy radiated as thermal radiation after the heating of pane components, typically characterized as the TTS value) is high.

[0007] There is therefore a need for composite glazing with photovoltaic components that has a low TTS value and ensures high thermal comfort.

[0008] Aerogels are highly porous solids known for their very low thermal conductivity and thermal insulation properties. WO2012154602A1 discloses an insulating glazing unit with an aerogel layer. US2014199805A1 discloses a solar cell with an aerogel-based electrode. US5221364A discloses a solar cell on an aerogel substrate.

[0009] CN203951415U discloses a composite pane with embedded photovoltaic elements. An aerogel layer is arranged on the surface of the inner pane facing away from the intermediate layer and the photovoltaic elements.

[0010] The present invention is based on the object of providing an improved composite pane with at least one integrated photovoltaic component, which has a low heat input and ensures a high level of thermal comfort.

[0011] The object is achieved according to the invention by a composite pane according to independent claim 1. Advantageous embodiments emerge from the subclaims.

[0012] The composite pane according to the invention comprises an outer pane and an inner pane, which are connected to each other via an intermediate layer. At least one photovoltaic component is embedded in the intermediate layer. The intermediate layer also contains an aerogel layer, which is spaced closer to the inner pane than the at least one photovoltaic component.

[0013] The present invention is based on the idea of providing an aerogel layer on the interior side of the composite pane, close to the photovoltaic component. Due to the thermally insulating properties of the aerogel layer, the heat input through the composite pane is reduced, in particular the interior emissivity of the composite pane. The thermal radiation of the heated photovoltaic component toward the inner pane is reduced. The aerogel layer also has acoustically insulating properties, which is advantageous for shielding disturbing external noise. It is very lightweight, so the overall weight of the composite pane is not significantly increased. These are major advantages of the present invention.

[0014] A photovoltaic component, within the meaning of the invention, is a one-piece electrical element for generating electrical energy or electrical current using the photovoltaic effect. The photovoltaic component is handled as a single component and preferably has only two electrical connections (two electrical poles, so to speak "positive and negative pole") via which the component as a whole is electrically contacted. The photovoltaic component can also be referred to as a photovoltaic element or solar element. A photovoltaic cell, within the meaning of the invention, is the smallest possible photovoltaic unit, comprising a single photovoltaically active absorber layer between a single front electrode and a single back electrode. The photovoltaic cell is not structurally subdivided further. The photovoltaic cell can also be referred to as a solar cell.A photovoltaic module, within the meaning of the invention, is a one-piece component comprising a plurality of interconnected or electrically connected photovoltaic cells. The photovoltaic cells can be connected in series or in parallel, or there can be groups of serially connected photovoltaic cells connected in parallel, or groups of parallel-connected photovoltaic cells connected in series. Serial connection of all solar cells is preferred. The photovoltaic module can also be referred to as a photovoltaic module or solar module.

[0015] The at least one photovoltaic component according to the invention can be or comprise a single photovoltaic cell or a photovoltaic module with a plurality of interconnected photovoltaic cells, the latter case being typically realized in practice.

[0016] The outer pane is the pane of the composite pane which, in the installed position, faces the sun or is intended to do so. The composite pane is typically intended to separate an interior space from the exterior environment in an opening (in particular a window opening, for example a window opening in a vehicle or a building). For the purposes of the invention, the term inner pane refers to the pane facing the interior space. The term outer pane refers to the pane facing the exterior space and the sun. The outer pane and the inner pane each have an exterior surface and an interior surface and a circumferential side edge surface running between them. For the purposes of the invention, the term exterior surface refers to the main surface which is intended to face the exterior space and the sun in the installed position.For the purposes of the invention, the interior-facing surface refers to the main surface intended to face the interior in the installed position. The interior-facing surface of the outer pane and the exterior-facing surface of the inner pane face each other and are connected by the intermediate layer.

[0017] According to the invention, the at least one photovoltaic component is embedded in the intermediate layer, i.e., arranged between the outer pane and the inner pane. The aerogel layer represents a layer of the intermediate layer and is arranged on the interior side of the at least one photovoltaic component, thus having a smaller distance from the inner pane (and, in the installed position, the interior) than the at least one photovoltaic component. Conversely, the at least one photovoltaic component is arranged on the outside of the aerogel layer, thus having a smaller distance from the outer pane (and, in the installed position, the external environment) than the aerogel layer.Viewed from above the composite pane, the aerogel layer preferably completely overlaps the at least one photovoltaic component. The at least one photovoltaic component is thus arranged entirely within the area bounded by the side edge of the aerogel layer and does not protrude beyond the aerogel layer. The term "at least one photovoltaic component" refers to the totality of all photovoltaic components present.

[0018] The composite pane can contain a single photovoltaic component or a plurality of photovoltaic components. If it has a plurality of photovoltaic components, all photovoltaic components are preferably arranged in the same plane or position of the composite pane. All photovoltaic components then have (at least approximately) the same distance from the outer pane or the inner pane. However, even if the photovoltaic components are arranged in different planes or positions of the composite pane, the aerogel layer on the interior side of all photovoltaic components is arranged at a smaller distance from the inner pane.

[0019] In principle, the composite pane can also comprise multiple aerogel layers, with all aerogel layers preferably being arranged on the interior side of the at least one photovoltaic component at a shorter distance from the inner pane. However, a single aerogel layer is preferred due to a simpler structure and easier production of the composite pane.

[0020] In a preferred embodiment, the at least one photovoltaic component is connected to the outer pane and the aerogel layer via a thermoplastic layer, and the aerogel layer is connected to the inner pane via another thermoplastic layer. The composite pane then comprises, in the specified order, at least: - the outer pane, - a first thermoplastic layer, - the at least one photovoltaic component or a layer with the at least one photovoltaic component, - a second thermoplastic layer, - the aerogel layer, - a third thermoplastic layer and - the inner pane.

[0021] The aerogel layer can alternatively be referred to as an aerogel layer, and the thermoplastic layers as thermoplastic layers.

[0022] The outer pane and the first thermoplastic layer are preferably clear and have no tints or colors to prevent attenuation of sunlight before it reaches the at least one photovoltaic component. The second thermoplastic layer, the aerogel layer, the third thermoplastic layer, and the inner pane can independently be clear, tinted, or colored.

[0023] The thickness of the aerogel layer can be selected according to the requirements of the specific application. In particular, the thermal conductivity of the aerogel (which in turn depends on the material, density, and porosity), the heat absorption of the at least one photovoltaic component (which in turn depends on the type of component and the surface coverage), and the desired heat input (i.e., the desired TTS value, the total radiated solar energy) play a role. The aerogel layer preferably has a thickness in the range of 0.1 mm to 10 mm, more preferably 0.2 mm to 8 mm, and most preferably 0.5 mm to 5 mm. This achieves good results in typical applications.

[0024] Contrary to what the name initially suggests, aerogels are not gels, but highly porous solids. The name comes from the fact that aerogels are typically made from gels, whereby the liquid component of the gel is replaced by a gas without collapsing the gel structure, for example through supercritical drying or freeze-drying. Structurally, aerogels consist of a branching of particle chains (dendritic structure) with very many interstices (pores), particularly in the form of open pores. The particle chains have contact points with one another, so that the aerogel can be thought of as a stable, sponge-like network. The particle chains themselves are often formed by the fusion of, for example, spherical particles. A very high volume fraction of aerogels consists of pores, particularly open pores. Therefore, aerogels have a very low density.The aerogel layer according to the invention is therefore lightweight, so that the weight of the laminated pane is not significantly increased even by comparatively thick aerogel layers. Aerogels can also exhibit high optical transparency, which can be particularly advantageous for glazing applications. Aerogels can be produced, for example, using sol-gel processes.

[0025] Intercalations may be present in the pores, for example, to influence the mechanical, thermal, or optical properties of the aerogel layer. The pores are typically filled with air, except for any intercalations. The aerogel layer according to the invention can also be referred to as a layer or layer made of an aerogel or based on an aerogel.

[0026] For the purposes of the invention, porosity refers to the proportion of the pore volume to the total volume of the aerogel. The aerogel layer according to the invention is preferably formed from an aerogel or based on an aerogel having a porosity of 50% to 99.98%, particularly preferably 80% to 99%, and most preferably 85% to 98%. The porosity can be determined by gas sorption measurement, in particular using carbon dioxide (CO2) as the measurement gas at a temperature of 273 K.

[0027] The pore size of the aerogel is preferably between 1 nm and 50 nm, particularly preferably between 10 nm and 40 nm. This refers in particular to the diameter of the typically approximately spherical pores. The pore size can also be determined using the aforementioned gas sorption measurement.

[0028] The density of the aerogel is preferably 0.16 mg / cm 3 up to 500 mg / cm 3 , particularly preferably 10 mg / cm 3up to 300 mg / cm 3 This refers to the bulk density based on the volume including the pore spaces, whereby the air in the pores is not included in the mass.

[0029] The particles that make up the network of particle chains typically have a size of 1 nm to 10 nm.

[0030] Aerogels can be formed from various materials (material of the particle chains). The aerogel of the aerogel layer according to the invention is preferably made of silicate, a polymer, carbon, cellulose, or a metal oxide. In principle, all polymers and metal oxides are suitable. Examples include polyimide for a polymer, and aluminum oxide, titanium oxide, zirconium oxide (all transparent and white or bluish), iron oxide (opaque, red, or yellow), chromium oxide (opaque, green, or blue), and vanadium oxide (opaque, olive green) for metal oxides. Strictly speaking, silicate aerosols do not have the chemical composition of a silicate, but rather SiO(OH). y (OR) z, where R is an organic radical and the parameters y and z depend on the manufacturing process. Nevertheless, they are generally referred to as such, and the term silicate is used accordingly in the context of the present invention. In English, the term "silica aerogel" is also commonly used (i.e., SiO2 aerogel). For the aerogel layer according to the invention, silicate aerogels, polymer aerogels, and cellulose aerogels are particularly preferred, in particular silicate aerogels and polymer aerogels. These aerogels have been well researched and are already commercially available in large numbers.

[0031] The aerogel layer according to the invention can be structurally designed differently and integrated into the composite pane, in particular - as a so-called blanket (“blanket”); this is understood to be a composite material consisting of an aerogel (particularly silicate aerogel) with inclusions that influence the mechanical properties (particularly glass fibers); blankets are flexible and can be supplied, for example, on rolls; - as felt (especially silicate aerogel felt); felts are flexible and can also be supplied, for example, on rolls; - as a film; films are flexible and can also be provided, for example, on rolls; they are typically made of or based on a polymer aerogel, which can optionally have inclusions; - as a rigid layer (“plate”); - in the form of granules (with particle sizes in the millimeter range, for example) or particles (with particle sizes in the micrometer range, for example).

[0032] The outer pane has (at least) one transparent region, which is referred to as the see-through region within the meaning of the invention. In the transparent see-through region, sunlight can pass through the outer pane and excite the at least one photovoltaic component. The transparent see-through region of the outer pane therefore defines an active region of the composite pane. This means that, in a plan view of the composite pane, the transparent region of the outer pane and the active region are congruent. The at least one photovoltaic component is arranged (at least partially, in particular largely or even completely) in the see-through region.

[0033] The outer pane can be made transparent as a whole, so that the see-through area encompasses the entire outer pane. In this case, the entire laminated pane forms the active area. The outer pane can also have an opaque masking area through which no sunlight can pass and which defines a masking area of the laminated pane. The active area then corresponds to the laminated pane minus the masking area. Such masking areas are particularly common in vehicle windows. They are typically formed by an opaque masking print on the interior surface of the outer pane. An enamel printing paste containing glass frits and a pigment, in particular black pigment, is printed onto the surface, for example using a screen printing process, and then fired.The masking area typically comprises a peripheral edge area of the outer pane that surrounds a central view-through area in a frame-like manner. However, the masking area can also comprise additional areas, which are designed, for example, as a type of cross bracing of the frame-like edge area.

[0034] Alternatively, a masking region can also be formed by having an opaque layer of the intermediate layer located between the at least one photovoltaic component and the outer pane, or by having an opaque film or plate embedded in the intermediate layer between the at least one photovoltaic component and the outer pane. Even then, no sunlight can reach the photovoltaic component in the masking region. In this case, the active area of the composite pane is also reduced in size, even though the outer pane is transparent overall. The above applies accordingly.

[0035] The at least one photovoltaic component can extend from the active area into the masking area. Although the areas located there do not contribute to power generation, this may be desirable for aesthetic reasons.

[0036] The aerogel layer according to the invention preferably completely covers at least the active region of the composite pane. It can cover the entire composite pane and extend to its side edges. However, if the composite pane has a masking region in which no photovoltaic components are present, no aerogel layer needs to be provided there. For example, it is possible for the aerogel layer to be arranged in a section of a thermoplastic layer that surrounds it in a frame-like manner, with the frame-like thermoplastic layer preferably being arranged in a circumferential peripheral masking region.

[0037] Opaque or transparent photovoltaic components can be used. Opaque photovoltaic components can be realized by having the photovoltaically active material (absorber layer) absorb in the visible spectral range and / or by using an opaque back electrode. Transparent photovoltaic components can be realized by having the photovoltaically active material absorb completely or at least largely in the infrared spectral range (and not absorbing in at least a large part of the visible spectral range) and by using transparent electrodes.

[0038] In a first embodiment of the composite pane according to the invention, the at least one photovoltaic component is opaque and completely covers the active region. The composite pane is then opaque as a whole. This can be achieved by using a single photovoltaic component that completely covers the active region. Alternatively, this can be achieved by using a plurality of photovoltaic components, with adjacent photovoltaic components being arranged flush with one another or overlapping. In this case, the aerogel layer can be transparent, translucent, or opaque.

[0039] In a second embodiment of the composite pane according to the invention, the at least one photovoltaic component is opaque and covers only part of the active region. Preferably, a plurality of photovoltaic components is present in the active region. A plurality of spaced-apart, opaque photovoltaic components can be present in the active region. Alternatively, several groups of photovoltaic components can be present, with the components of each group being flush with one another or overlapping one another so that each group covers a closed area, and the groups are spaced from one another. In any case, only part of the active region is occupied or covered with photovoltaic components, while another part of the active region is not occupied by photovoltaic components.In other words, at least one photovoltaic component (or the majority of photovoltaic components) is opaque and only partially covers the active region. The composite pane is then partially opaque and partially transparent, meaning that it has opaque and transparent regions. The size of the photovoltaic components and the spacing can be freely selected for the application in order to adjust the degree of coverage of the active region with photovoltaic components as desired. In this case, the aerogel layer is preferably transparent or translucent so that light can pass through the regions not covered by photovoltaic components. In the case of a translucent aerogel layer, the aforementioned transparent regions are, of course, strictly speaking, not transparent, but translucent.

[0040] In the aforementioned first and second embodiments, opaque photovoltaic components are used, which are typically (at least primarily) photovoltaically active in the visible spectral range. Therefore, the interior-side surface of the outer pane facing the intermediate layer can optionally be provided with an IR-reflecting coating. The IR-reflecting coating preferably has reflective properties in the near-infrared range and is suitable for reflecting infrared components of solar radiation, so that the underlying layers of the composite pane (in particular also the at least one photovoltaic component) and the interior space delimited by the composite pane are heated to a lesser extent. Such IR-reflecting coatings are also referred to as solar control coatings.The IR-reflective coating is typically a stack of thin films with at least one layer based on a metal, in particular silver. Dielectric layers are also usually present to optimize the optical properties of the coating (for example, anti-reflective layers or layers for influencing the structure of the metallic layer) and / or to protect the metallic layer from corrosion. The dielectric layers can, for example, be based on silicon nitride, zinc oxide, tin-zinc oxide, silicon-metal mixed nitrides such as silicon zirconium nitride, zirconium oxide, niobium oxide, hafnium oxide, tantalum oxide, tungsten oxide, or silicon carbide. Alternatively, the IR-reflective coating can also be applied to a carrier film (for example, made of PET) that is arranged in the intermediate layer between the at least one photovoltaic component and the outer pane.

[0041] In a third embodiment of the composite pane according to the invention, the at least one photovoltaic component is transparent. It preferably completely covers the active region to ensure optimal energy yield. This can in turn be achieved by using a single photovoltaic component that completely covers the active region, or by using a plurality of flush or overlapping photovoltaic components. Alternatively, it is also possible in principle for a plurality of spaced-apart photovoltaic components (or a plurality of spaced-apart groups of photovoltaic components) to be present in the active region. In this case, the aerogel layer is preferably transparent or translucent so that light can pass through the active region of the composite pane. The active region is then entirely transparent or translucent.

[0042] Since transparent photovoltaic components are sensitive in the infrared spectral range, the composite pane in the third embodiment preferably does not have an IR-reflecting coating (sun protection coating) as described above (on the interior-facing surface of the outer pane or on a carrier film between the photovoltaic component and the outer pane). The interior-facing surface of the outer pane is preferably uncoated and, in particular, not provided with an IR-reflecting coating.

[0043] An opaque aerogel layer is understood to be a layer through which no visibility is possible. An opaque aerogel layer preferably has a light transmission of less than 5%, more preferably less than 2%, in particular 0%. A transparent aerogel layer is understood to be a layer through which visibility is possible, so that the viewer can see objects located behind it. However, the aerogel layer can certainly be tinted to reduce light transmission. A transparent aerogel layer preferably has a light transmission of more than 10%, more preferably more than 50%, in particular more than 70%. A translucent aerogel layer is understood to be a layer through which light passes but is strongly scattered, so that the viewer cannot see objects located behind it clearly (at most only vaguely).

[0044] The at least one photovoltaic component is suitable for converting sunlight directly into electrical energy. For this purpose, the photovoltaic component has a photovoltaically active absorber layer between a front electrode and a rear electrode (strictly speaking, each photovoltaic cell has its own separate absorber layer and its own separate electrodes if the component comprises several interconnected photovoltaic cells as a solar module). The front electrode faces the outer pane of the composite pane, and the rear electrode faces the inner pane. The electrodes are, in particular, surface electrodes that cover the entire absorber layer. When sunlight is absorbed, free charge carriers are generated in the absorber layer (photovoltaic effect as a special case of the internal photoelectric effect), which are discharged via the electrodes to generate electrical energy or an electric current.The absorber layer often contains dopants to optimize the transport of charge carriers to the electrodes.

[0045] In principle, all types of photovoltaic components or cells can be used within the scope of the present invention. There are no restrictions on specific photovoltaic cells. In particular: - thin-film cells or thick-film cells can be used; in a thin-film cell, the absorber layer is a thin layer with a thickness of, for example, 0.5 µm to 3 µm; in thick-film cells, the absorber layer has a greater thickness (for example, 20 µm to 500 µm); - any photovoltaically active material can be used for the absorber layer, for example inorganic semiconductors (such as silicon, cadmium telluride, gallium arsenide, indium gallium arsenide, indium gallium phosphide, CI(G)S chalcopyrite semiconductors or combinations thereof) or organic conjugated polymers, organic conjugated oligomers or organic dyes; - the crystal structure of the absorber layer can be monocrystalline, polycrystalline or amorphous.

[0046] Thick-film cells, for example, can have an absorber layer based on monocrystalline or polycrystalline silicon. Thin-film cells, for example, can have an absorber layer based on amorphous or polycrystalline (especially microcrystalline) silicon, on gallium arsenide, on cadmium telluride, or on organic conjugated polymers. Thin-film cells can also have a chalcopyrite semiconductor such as a compound from the copper-indium-sulfur / selenium (CIS; e.g., CuInSe2) or a compound from the copper-indium-gallium-sulfur / selenium (CIGS; e.g., Cu(InGa)(SSe)2) group.

[0047] Thin-film cells are preferred in the context of the present invention because they are typically flexible and can therefore adapt to a curved shape of the composite pane, as is particularly common in vehicle windows.

[0048] The front electrode and the rear electrode can, for example, be formed as thin conductive or semiconductive layers with thicknesses of preferably from 50 nm to 2 µm. The layers can contain, for example, metals such as silver, gold, copper, molybdenum, titanium, tungsten, nickel, titanium, chromium, tantalum, aluminum-doped zinc oxide or transparent conductive oxides such as indium tin oxide. The front electrode and / or the rear electrode can, however, also be formed, for example, as a mesh of thin wires containing, for example, aluminum, copper, silver and / or gold. At least the front electrode is transparent so that sunlight can penetrate the absorber layer. The electrodes can be formed as individual layers or as a stack of several layers.

[0049] In addition to the absorber layer and the electrodes, the photovoltaic component may of course comprise further individual layers known to the person skilled in the art, for example a buffer layer for adapting the electronic properties between the absorber layer and an electrode layer or diffusion barrier layers.

[0050] Foil-like photovoltaic components can also be used. In a foil-like photovoltaic component, the electrodes and the absorber layer are independently printed, wet-chemically applied, or vapor-deposited onto a carrier film. They typically comprise thin-film photovoltaic cells. Foil-like photovoltaic components can be supplied on rolls and are very easy to process and integrate into the composite pane, which makes them particularly advantageous. They are also flexible and easily adapt to a curved shape of the composite pane. The carrier film can be made of or based on, for example, polyethylene terephthalate (PET), polypropylene, polyvinyl chloride, fluorinated ethylene propylene, polyvinyl fluoride, or ethylene tetrafluoroethylene. The thickness of the carrier film is, for example, from 10 µm to 300 µm.

[0051] The at least one photovoltaic component can optionally be surrounded by a further thermoplastic layer, which in the sense of the invention is also referred to as a capsule layer. The capsule layer is in particular designed like a frame and arranged in a circumferential edge region of the composite pane, wherein the at least one photovoltaic component is, as it were, inserted into the frame-like capsule layer. The capsule layer has at least one recess into which the at least one photovoltaic component is inserted. The capsule layer can be formed by a thermoplastic film (or several thermoplastic films stacked one above the other) into which the recess has been cut out. Alternatively, the capsule layer can also be composed of several film sections around the at least one photovoltaic component. The capsule layer preferably has approximately the same thickness as the at least one photovoltaic component.This compensates for the local thickness difference introduced by the at least one locally limited photovoltaic component, thus preventing air pockets, preventing glass breakage during lamination, and resulting in an improved visual appearance. If multiple photovoltaic components are present that only partially cover the active area of the laminated pane, the capsule layer is preferably also arranged in the areas not equipped with photovoltaic components.

[0052] The interior-facing surface of the inner pane facing away from the intermediate layer is preferably provided with an emissivity-reducing coating. Emissivity-reducing coatings are also known as heat-reflecting coatings, low-emissivity coatings, or LowE coatings (low emissivity). Emissivity is the measure that indicates how much heat radiation the pane emits into an interior space in the installed position compared to an ideal heat radiator (a black body). Emissivity-reducing coatings prevent heat from radiating into the interior (IR components of solar radiation and, in particular, the thermal radiation of the pane itself) and also prevent heat from radiating out of the interior. They exhibit reflective properties against infrared radiation, particularly against thermal radiation in the spectral range of 5 µm - 50 µm (cf.This effectively improves thermal comfort in the interior. At high outside temperatures and in direct sunlight, the emissivity-reducing coatings can at least partially reflect the heat radiation emitted by the entire pane toward the interior. At low outside temperatures, they can reflect the heat radiation emitted from the interior, thus reducing the effect of the cold pane as a heat sink. The emissivity-reducing coating further increases thermal comfort in the interior.

[0053] The emissivity-reducing coating is typically a transparent stack of thin films. The emissivity-reducing coating has at least one, preferably precisely one, electrically conductive layer, which provides the IR-reflecting properties. The conductive layer is preferably based on a transparent conductive oxide (TCO), in particular indium tin oxide (ITO), alternatively indium zinc mixed oxide (IZO), gallium-doped tin oxide (GZO), fluorine-doped tin oxide (FTO, SnO2:F), antimony-doped tin oxide (ATO, SnO2:Sb), or niobium-doped titanium oxide (TiO2:Nb). Unlike metals, TCOs are not susceptible to corrosion, so they can be used on the exposed interior surface of the inner pane.In addition to the conductive layer, the coating typically comprises dielectric layers (e.g. based on silicon oxide or nitride), which serve in particular to optimize the optical properties (e.g. light transmission) or serve as barrier layers to regulate oxygen diffusion during the deposition of the coating.

[0054] The outer pane and the inner pane are preferably glass panes, particularly preferably made of soda-lime glass, as is common for window panes. However, one or both of the panes can also be made of other types of glass, such as quartz glass, borosilicate glass, or aluminosilicate glass, or of rigid, clear plastics, such as polycarbonate or polymethyl methacrylate. The thicknesses of the outer pane and the inner pane, independently of one another, are preferably between 0.5 mm and 5 mm, particularly preferably between 1 mm and 3 mm.

[0055] The thermoplastic layers of the intermediate layer are preferably based on polyvinyl butyral (PVB), ethylene-vinyl acetate (EVA), or polyurethane (PU), or on mixtures or copolymers or derivatives thereof, particularly preferably based on PVB. This means that the layer largely contains said polymer (a proportion greater than 50% by weight). In addition to the polymer, the layer may contain further additives, for example, plasticizers, UV absorbers, or stabilizers. Each thermoplastic layer is preferably formed from at least one thermoplastic film. The thickness of each film is preferably between 0.2 mm and 1 mm. For example, PVB films with standard thicknesses of 0.38 mm or 0.76 mm can be used.

[0056] All layers arranged on the outside of the at least one photovoltaic component are preferably clear, without tints or colors, so that sunlight can reach the photovoltaic component as unhindered as possible. They preferably have a light transmittance of at least 70%, more preferably at least 80%, and most preferably at least 90%. This applies in particular to the outer pane and the first thermoplastic layer, via which the at least one photovoltaic component is connected to the outer pane. The outer pane is preferably made of clear glass and has a light transmittance of at least 90% in the visible spectral range. The front electrode is also preferably transparent, with a light transmittance of at least 80%, more preferably at least 90%. The first thermoplastic layer is preferably formed from a clear film.The second and third thermoplastic layers and the inner pane can be clear, tinted or colored independently of each other.

[0057] The laminated pane can be flat or cylindrically or spherically curved. Spherically curved laminated panes are particularly common for vehicle windows, while flat laminated panes are used for building glazing.

[0058] The composite pane can be manufactured by stacking the individual layers in the intended sequence to form a layer stack and then laminating them together. Known processes can be used for this purpose, such as autoclave processes, vacuum bag processes, vacuum ring processes, calender processes, vacuum laminators, or combinations thereof. The bonding of the outer and inner panes is usually achieved under the influence of heat, vacuum, and / or pressure.

[0059] The layer stack preferably includes, in the order given: - the outer pane - a first thermoplastic film forming a first thermoplastic layer of the intermediate layer, - the at least one photovoltaic component, preferably enclosed in a frame-like thermoplastic capsule layer with at least one recess, - a second thermoplastic film forming a second thermoplastic layer of the intermediate layer, - the aerogel layer - a third thermoplastic film forming a third thermoplastic layer of the intermediate layer, - the inner pane.

[0060] Before or during stacking of the layers, the at least one photovoltaic component is provided with the required electrical connections. Electrical conductors extend beyond the side edge of the layer stack, by means of which the at least one photovoltaic component can later be electrically contacted, for example for connection to an electrical system, a battery, or one or more individual electrical loads. If a plurality of photovoltaic components is present, they are electrically connected to one another (at least in groups) and thus interconnected, so that all photovoltaic components (or each group of photovoltaic components) can be externally electrically contacted via common electrical conductors.

[0061] The composite pane according to the invention can be used in buildings or in means of transport for land, air, or water traffic, in particular as a vehicle pane or building glazing. The composite pane is particularly preferably used as a vehicle roof pane, in particular as a roof pane of a passenger car or truck.

[0062] The invention is explained in more detail with reference to a drawing and exemplary embodiments. The drawing is a schematic representation and not to scale. The drawing does not limit the invention in any way. It shows: Fig. 1 a plan view of a first embodiment of the composite pane according to the invention, Fig. 2 a cross-section through the composite pane made of Fig. 1, Fig. 3 a plan view of a second embodiment of the composite pane according to the invention, Fig. 4 a cross-section through the composite pane made of Fig. 3, Fig. 5 a plan view of a third embodiment of the composite pane according to the invention and Fig. 6 a cross-section through the composite pane made of Fig. 5.

[0063] Fig. 1 and Fig. 2 each show a detail of a first embodiment of the composite pane according to the invention. The composite pane is a vehicle roof pane. The composite pane consists of an outer pane 1 and an inner pane 2, which are connected to one another by an intermediate layer 3. The outer pane 1 and the inner pane 2 are made of soda-lime glass. The outer pane 1 has a thickness of 2.1 mm, and the inner pane 2 has a thickness of 1.6 mm. In the installed position, the outer pane 1 faces the outside environment, while the inner pane 2 faces the vehicle interior.

[0064] The outer pane 1 has an opaque masking area M, which is arranged circumferentially in the edge region and surrounds a central transparent see-through area D in a frame-like manner. In the masking area M, a black masking print 8 is applied to the interior-side surface of the outer pane 1 facing the intermediate layer 3. The see-through area D defines an active area A of the composite pane, in which electrical energy can be generated by photovoltaics. For this purpose, a photovoltaic component 4 is embedded in the intermediate layer 3. The photovoltaic component 4 is opaque, completely covers the active area A and extends from there into the masking area M. The composite pane is therefore completely opaque overall.

[0065] The intermediate layer 3 has a multi-layer structure. Starting with the outer pane 1, it comprises the following components: - a first thermoplastic layer 3a, - a layer with the photovoltaic component 4, - a second thermoplastic layer 3b, - an aerogel layer 5 and - a third thermoplastic layer 3c adjacent to the inner pane 2.

[0066] The layer with the photovoltaic component 4 contains a thermoplastic capsule layer 3d, which is formed like a frame around a recess in which the photovoltaic component 4 is arranged.

[0067] The thermoplastic layers 3a, 3b, and 3c are each formed from a PVB film with a thickness of 0.76 mm. The thermoplastic capsule layer 3d is formed from a PVB film with a thickness of 0.38 mm, which approximately corresponds to the thickness of the photovoltaic component 4.

[0068] The layer with the photovoltaic component 4 is connected to the outer pane 1 via the first thermoplastic layer 3a and, on the opposite side, to the aerogel layer 5 via the second thermoplastic layer 3b. The aerogel layer 5 is, in turn, connected to the inner pane 2 on the other side via the third thermoplastic layer 3c.

[0069] The photovoltaic component 4 is, for example, a film-like component comprising a thin photovoltaically active absorber layer between a front electrode and a rear electrode on a carrier film. Only a single large-area photovoltaic component 4 is present, which is divided into a plurality of interconnected photovoltaic cells (by suitably positioned insulation lines in the electrodes and the absorber layer). Alternatively, complete coverage of the active region A can also be achieved by a plurality of photovoltaic components 4 that are interconnected, with adjacent components 4 being flush with one another or overlapping one another.

[0070] The photovoltaic component 4 absorbs light in the visible spectral range and (partially) converts it photovoltaically into electrical current, which is the basis of its opacity. The photovoltaic component 4 is heated in the process. It then emits thermal radiation, which is partially directed toward the inner pane 2 and the vehicle interior. It thus contributes significantly to the so-called interior-side emissivity of the laminated pane. The vehicle interior is thereby heated, reducing thermal comfort for the vehicle occupants. The aerogel layer 5 has the task of reducing the interior-side emissivity. It has thermal-insulating properties that enable it to do so. The vehicle interior is shielded by the aerogel layer 5 from the thermal radiation of the photovoltaic component 4 (and also from the thermal radiation of the outer pane 1).

[0071] Aerogel layer 5, for example, has a thickness of 3 mm. It is designed as a so-called blanket, consisting of a silicate aerogel with glass fiber inclusions, which provide mechanical stability and flexibility to aerogel layer 5. Since the composite pane is opaque anyway, it doesn't matter whether aerogel layer 5 is opaque, transparent, or translucent.

[0072] An emissivity-reducing coating 6 is applied to the interior-side surface of the inner pane 2, facing away from the intermediate layer 3. Such coatings are also known as low-E coatings. The emissivity-reducing coating 6 has reflective properties in the mid-IR range. The emissivity-reducing coating 6 further reduces the interior-side emissivity of the laminated pane. In particular, it shields the vehicle interior from the thermal radiation of the inner pane 2, which the aerogel layer 5 has no influence on.

[0073] For the sake of simplicity, the electrical connections of the photovoltaic component 4 that protrude beyond the side edge of the laminated pane are not shown. These connections can be used to connect the photovoltaic component 4 to the vehicle's on-board electrical system, for example, to charge the vehicle battery.

[0074] Fig. 3 and Fig. 4 each show a detail of a second embodiment of the composite pane according to the invention. The composite pane is constructed similarly to the first embodiment of the Fig. 1 and Fig. 2. In particular, the outer pane 1 with the cover print 8, the inner pane 2 with the emissivity-reducing coating 6 and the thermoplastic layers 3a, 3b, 3c are designed in the same way as in the Fig. 1 and Fig. 2. In the following, only the differences to the first version will be discussed.

[0075] A plurality of photovoltaic components 4 are present, covering only a portion of the active region A. Another portion of the active region A has no photovoltaic components 4. The active region A has five regions, each provided with a photovoltaic component 4 and spaced from one another by regions without a photovoltaic component 4. Alternatively, it is also possible for each of the five regions to be provided with a plurality of photovoltaic components 4 that are interconnected, with adjacent components 4 being flush with one another or overlapping one another.

[0076] The photovoltaic components 4 (and thus the areas of the laminated pane containing them) are also opaque in this design. However, sunlight can penetrate into the vehicle interior through the intermediate areas and the peripheral areas without photovoltaic components 4. The aerogel layer 5 should therefore not be opaque, but transparent or translucent.

[0077] The aerogel layer 5, for example, has a thickness of 2 mm. It is formed, for example, as a flexible film made of a transparent or translucent polymer aerogel.

[0078] In the second embodiment, the layer with the photovoltaic components 4 also contains, in addition to the photovoltaic components 4 themselves, a thermoplastic capsule layer 3d. The thermoplastic capsule layer 3d is again arranged in a frame-like manner around the entire photovoltaic components 4 and additionally in the spaces between adjacent photovoltaic components 4. In other words, the thermoplastic capsule layer 3d forms a frame around each individual photovoltaic component 4.

[0079] An IR-reflecting coating 7 is arranged on the interior-side surface of the outer pane 1, facing the intermediate layer 3. The IR-reflecting coating 7 is a so-called sun protection coating with IR-reflecting properties in the near IR range, which reflects infrared components of solar radiation. The IR-reflecting coating 7 therefore reduces the heating of the vehicle interior due to direct solar radiation as well as the heating of the underlying layers of the composite pane (in particular the photovoltaic components 4), which in turn cause indirect heat input due to thermal radiation. Since the photovoltaic components absorb and are sensitive at least primarily in the visible spectral range, as indicated by their opacity, the current yield of the photovoltaic components 4 is not significantly reduced by the IR-reflecting coating 7.

[0080] If the light irradiation into the vehicle interior is to be reduced, the inner pane 2, the second thermoplastic layer 3b, the aerogel layer 5, and / or the third thermoplastic layer 3c can be tinted or colored. The outer pane 1 and the first thermoplastic layer 3a should be clear to optimize the yield of the photovoltaic components 4.

[0081] Fig. 5 and Fig. 6 each show a detail of a third embodiment of the composite pane according to the invention. The composite pane is constructed similarly to the first embodiment of the Fig. 1 and Fig. 2. In particular, the outer pane 1 with the cover print 8, the inner pane 2 with the emissivity-reducing coating 6 and the thermoplastic layers 3a, 3b, 3c are designed in the same way as in the Fig. 1 and Fig. 2. In the following, only the differences to the first version will be discussed.

[0082] As in the first embodiment, only a single (e.g., film-like) photovoltaic component 4 is present, which completely covers the active region A of the composite pane. Alternatively, the complete coverage of the active region A can also be achieved by a plurality of photovoltaic components 4 that are interconnected, with adjacent components 4 being flush with one another or overlapping one another. In the third embodiment, the layer with the photovoltaic component 4 also contains, in addition to the photovoltaic component 4 itself, a thermoplastic capsule layer 3d. The photovoltaic component is arranged in a recess of the capsule layer 3d, so that the capsule layer 3d again surrounds the photovoltaic component 4 like a frame. The photovoltaic component is again a film-like component.

[0083] In contrast to the first embodiment, the photovoltaic component 4 is not opaque, but transparent. This is achieved in particular by the fact that the photovoltaically active absorber layer is not or hardly sensitive in the visible spectral range and absorbs sunlight, but rather in the near infrared spectral range. The aerogel layer 5 is transparent or translucent, so that the active region A of the composite pane is transparent or translucent as a whole.

[0084] Aerogel layer 5, for example, has a thickness of 3 mm. It is formed, for example, as a rigid plate made of a silicate aerogel without any inclusions.

[0085] For optimal power yield of the photovoltaic component 4, it is advantageous if the highest possible proportion of the infrared radiation from the sun's rays hits the photovoltaic component. The outer pane 1 is therefore not provided with an IR-reflecting coating 7, as in the second embodiment of the Fig. 3 and Fig. 4 is present and in the first design of the Fig. 1 and Fig. 2 could be equally present.

[0086] If the light irradiation into the vehicle interior is to be reduced, the inner pane 2, the second thermoplastic layer 3b, the aerogel layer 5 and / or the third thermoplastic layer 3c can be tinted or colored.

[0087] In all embodiments, the aerogel layer 5 can also be surrounded in a frame-like manner by a further thermoplastic capsule layer, which is arranged in the masking region M, and / or have an edge seal, for example in the form of a polymeric adhesive tape. List of reference symbols: 1 outer pane 2 inner pane 3 Intermediate layer 3a first thermoplastic layer 3b second thermoplastic layer 3c third thermoplastic layer 3d thermoplastic capsule layer 4 photovoltaic component 5 aerogel layer 6 emissivity-reducing coating (LowE coating) 7 IR-reflective coating (sun protection coating) 8 Cover print D Viewing area of the outer pane 1 M Masking area of the outer pane 1 A active area of the composite pane X - X' intersection line Y - Y' intersection line Z - Z' intersection line QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 03028114A2

[0002] EP 1036683A2

[0003] WO 2013182398A1

[0004] WO 2013182399A1

[0004] WO 2019110172A1

[0005] WO 2012154602A1

[0008] US 2014199805A1

[0008] US 5221364A

[0008] CN 203951415U

[0009] Cited non-patent literature

[0000] Standard DIN EN 12898:2019-06

[0052]

Claims

[1] Composite pane, comprising an outer pane (1) and an inner pane (2) which are connected to one another via an intermediate layer (3), wherein at least one photovoltaic component (4) is embedded in the intermediate layer (3) and wherein the intermediate layer (3) contains an aerogel layer (5) which has a smaller distance from the inner pane (2) than the at least one photovoltaic component (4). [2] Composite pane according to claim 1, which comprises in the order given: - the outer pane (1), - a first thermoplastic layer (3a), - the at least one photovoltaic component (4), - a second thermoplastic layer (3b), - the aerogel layer (5), - a third thermoplastic layer (3c) and - the inner pane (2). [3] Composite pane according to claim 1 or 2, wherein the aerogel layer (5) has a thickness of 0.1 mm to 10 mm, preferably of 0.5 mm to 5 mm. [4] Composite pane according to one of claims 1 to 3, wherein the aerogel layer (5) is formed on the basis of a silicate aerogel or polymer aerogel. [5] Composite pane according to one of claims 1 to 4, wherein the aerogel layer (5) is formed on the basis of an aerogel which has a porosity of 50% to 99.98%, preferably of 80% to 99%, determined by gas sorption measurement. [6] Composite pane according to one of claims 1 to 5, wherein the outer pane (1) has a transparent see-through region (D) which defines an active region (A) of the composite pane, and wherein the aerogel layer (5) completely covers at least the active region (A). [7] Composite pane according to claim 6, wherein the at least one photovoltaic component (4) is opaque and completely covers the active region (A). [8] Composite pane according to claim 6, wherein the at least one photovoltaic component (4) is opaque and covers only a part of the active region (A). [9] Composite pane according to claim 7 or 8, wherein the surface of the outer pane (2) facing the intermediate layer (3) is provided with an IR-reflecting coating (7). [10] Composite pane according to claim 6, wherein the at least one photovoltaic component (4) is transparent and preferably completely covers the active region (A). [11] Composite pane according to claim 8 or 10, wherein the aerogel layer (5) is transparent or translucent. [12] Composite pane according to one of claims 1 to 11, wherein the surface of the inner pane (2) facing away from the intermediate layer (3) is provided with an emissivity-reducing coating (6). [13] Composite pane according to one of claims 1 to 12, wherein the at least one photovoltaic component (4) is designed in the form of a film. [14] Composite pane according to one of claims 1 to 13, wherein the outer pane (1) and the inner pane (2) are made of soda-lime glass.

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