DE102008037814A1 - Photovoltaic solar module for use in electric energy generating device, has frame made of polyurethane, where frame preset elasticity modulus and specific thermal expansion coefficient, which are measured parallel to module edges - Google Patents

Abstract

The solar module has a frame made of polyurethane, which completely or partially surrounds the solar module. The frame has an elongation at break of 50 percentage, an elasticity modulus of 30 Newton per square millimeter and a thermal expansion coefficient of 80x 10 power-6 per Kelvin. The elasticity modulus and the thermal expansion coefficient are measured parallel to module edges. The frame comprises natural or mineral material, which are selected from the group such as mica, wollastonite, glass fiber, carbon fiber or aramid fiber. An independent claim is also included for a method for production of a photovoltaic solar module.

Description

The The present invention relates to a photovoltaic solar module, a method for its production and a device for generating electrical energy, which makes use of such a solar module.

Under Solar modules are components for the direct generation of Electricity from sunlight. Key factors for a cost-efficient generation of solar power is the efficiency the solar cells used, as well as the production costs and the durability the solar modules.

One Solar module usually consists of a framed composite made of glass, interconnected solar cells, an embedding material and a Back side structure. The individual layers of the solar module have to perform the following functions.

The Front glass protects against mechanical and weather influences. It must have the highest transparency to absorption losses in the optical spectral range from 300 nm to 1150 nm and thus efficiency losses the silicon solar cells commonly used for power generation keep as low as possible. Usually hardened, low-iron white glass (3 or 4 mm thick), its transmittance in the above spectral range is 90 to 92%.

The Embedding material (mostly EVA (ethyl vinyl acetate) films are used) serves to bond the entire module network. EVA melts during a lamination process at about 150 ° C, flows in the spaces between the soldered solar cells and is thermally crosslinked. A formation of air bubbles that too Reflection losses will result from a lamination avoided under vacuum.

The Module back protects the solar cells and the Embedding material from moisture and oxygen. Furthermore serves as a mechanical protection against scratching, etc. when mounting of the solar modules and as electrical insulation. As back construction can used another glass or a composite sheet become. Essentially, the variants PVF (polyvinyl fluoride) -PET (Polyethylene terephthalate) -PVF or PVF-aluminum PVF used.

The In encapsulation materials used in solar module construction must in particular good barrier properties against water vapor and oxygen exhibit. By water vapor or oxygen, the solar cells itself not attacked, but it comes to a corrosion of the metal contacts and a chemical degradation of the EVA embedding material. A destroyed one Solar cell contact leads to a complete failure of the module, since normally all solar cells in a module are electrically serial be interconnected. A degradation of the EVA is evident in one Yellowing of the module, combined with a corresponding reduction in performance by light absorption as well as a visual deterioration. today About 80% of all modules are equipped with one of the composite films described above encapsulated on the back, in about 15% of the solar modules Glass is used for front and back. In this case, as embedding material, in some cases highly transparent, rather than EVA, however only slowly (several hours) hardening casting resins for use.

In order to achieve competitive electricity generation costs of solar power despite the relatively high investment costs, solar modules must achieve long operating times. Today's solar modules are therefore designed for a service life of 20 to 30 years. In addition to high weathering stability, high demands are placed on the thermal stability of the modules, whose temperature during operation can fluctuate cyclically between 80 ° C at full solar irradiation and temperatures below the freezing point. Accordingly, solar modules are subjected to extensive stability tests (standard tests according to IEC 61215 and IEC 61730 ), which include weathering tests (UV irradiation, damp heat, temperature changes), but also hailstorms and electrical insulation tests.

On Modular production accounts for 30% of the total costs a relatively high proportion of the total costs for photovoltaic modules. This large proportion of module production is due to high material costs (including embedding material, frame, backside multilayer film) and by long process times, d. H. low productivity conditionally. Still are often the ones described above Individual layers of the module composite assembled by hand and aligned. In addition, the relative lead slow melting of the EVA hot melt adhesive and lamination of the module assembly at about 150 ° C and under vacuum at cycle times of about 20 to 30 minutes per module.

Due to the relatively thick front glass pane, conventional solar modules also have a high Ge weight, which in turn makes stable and expensive holding structures necessary. The heat dissipation is solved unsatisfactory in today's solar modules. At full solar irradiation, the modules heat up to 80 ° C, which leads to a temperature-related deterioration of the solar cell efficiency and thus ultimately to an increase in the cost of solar power.

in the The state of the art solar modules are mainly with used a frame made of aluminum. Although this is a Light metal acts, but makes its weight not one negligible contribution to the total weight. This is especially with larger modules a disadvantage that requires elaborate holding and fastening structures.

Around to prevent the entry of water and oxygen, said Aluminum frame on its inside facing the solar module an additional seal on. Furthermore is disadvantageous that aluminum frame made of rectangular profiles be prepared and therefore strong in terms of their shape is restricted.

To reduce the solar module weight, to avoid an additional sealing material and to increase the design freedom describe US 4,830,038 and US 5,008,062 the attachment of a plastic frame around the respective solar module, which is obtained by the RIM method (Reaction Injection Molding).

Preferably, the polymeric material used is an elastomeric polyurethane. The said polyurethane should preferably have an E modulus in a range of 200 to 10,000 psi (corresponding to about 1.4 to 69.0 N / mm ² ).

to Reinforcement of the frame are described in these two patents various possibilities described. So can Reinforcement members of, for example, a polymeric material, Steel or aluminum in the formation of the frame with in these to get integrated. Also, fillers can be used be introduced into the frame material. These may be for example, platelet-shaped fillers like the mineral wollastonite or needle-like / fibrous Fillers such as glass fibers act.

Similarly describes DE 37 37 183 A1 also a method for producing the plastic frame of a solar module, wherein the Shore hardness of the material used is preferably adjusted so that a sufficient rigidity of the frame and an elastic receptacle of the solar generator is ensured.

DE 10 2005 032 716 A1 describes flexible solar modules in which the frame has a permanently elastic-flexible consistency. In this case, it is necessary to set the rigidity of the plastic material low and to largely dispense with fillers, so that the frame itself remains bendable.

by virtue of the different coefficients of thermal expansion of Polyurethane or glass and the significant shrinkage of Polyurethane systems have always been subject to delamination and penetration of moisture into the inner region of the solar module on, which ultimately led to the destruction of the module.

Solar modules, which are inserted into roof structures, must meet the requirements according to the building code DIN 4102-7 fulfill. In particular, they must demonstrate the resistance to flying fire and radiant heat.

It is therefore an object of the present invention, a solar module to provide these disadvantages of the prior art avoids. The solar module should in particular a sufficient Identify composite long-term stability that prevents Delaminations and / or moisture ingress occur. Farther It is a task to design the solar module so that it is easy to handle. It must have a sufficient Have stiffness, but may again not too low Have elongation at break, so it with a low impact stress not directly destroyed (for example, by Kantenabplatzer when mounting on a construction site). It is also a task the present invention, the solar module to be designed so that it has sufficient flame retardancy.

In a first embodiment, the object underlying the invention is achieved by a photovoltaic solar module with a completely or partially encircling frame made of polyurethane, wherein the frame is characterized in that it
an elongation at break of at least 50%,
an E-modulus of at least 30 N / mm ² and
has a thermal expansion coefficient of up to α = 80 · 10 ^-6 / K, wherein the modulus of elasticity and the thermal expansion coefficient are measured in parallel to the module edges.

The the aforementioned measured values for the modulus of elasticity and the expansion coefficient are measured in the fiber direction, provided that anisotropic fillers partially or completely used. At the filling the frame shape with the still liquid polyurethane Anisotropic fillers (for example, fibers) accordingly the flow direction parallel to the module edges. Transverse to the fiber direction (and to the edges) the coefficient of expansion is greater and the modulus of elasticity is smaller, but within the meaning of the present invention is irrelevant.

It has surprisingly been found that a photovoltaic solar module with such a framework by the combination of these three macroscopic properties (elongation at break, Young's modulus, thermal expansion coefficient) combines the desired properties:
Due to its sufficiently high modulus of elasticity, such a frame has a sufficiently high stability or rigidity. It is therefore preferred if the frame has an E-modulus of at least 40, particularly preferably of at least 60 N / mm ² , very particularly preferably of at least 70 N / mm ² , measured in each case parallel to the module edge.

By a sufficiently high rigidity of the frame and thus the solar module according to the invention is essentially not flexible, so in particular is not rollable, as in DE 10 2005 032 716 A1 is described. It is thus easy to handle and does not bend even after a long time (for example, with a spaced attachment to non-vertical surfaces).

However, the modulus of elasticity alone is not sufficient for a sufficient description of the polyurethane-comprehensive framework according to the invention. For example, many polyurethane materials also have an E-modulus of at least 30 N / mm ² , measured parallel to the module edge, but are unsuitable for the present invention in that they are too brittle, that is, inelastic. In these cases, an impact stress acting on the solar module would namely transfer unhindered to the actual solar module inside the frame, which can very easily lead to its damage (breakage, crack or the like).

One Another important aspect of the present invention is the edge protection. Break brittle materials with low elongation at break or splinter. Elastic materials with higher elongation at break are therefore suitable for mounting in the robust environment of a construction site more suitable. For this reason, the inventive Frame characterized by a high elongation at break. Particularly preferred is an elongation at break of at least 80%, very particular preference is given to an elongation at break of at least 100%.

Even with these two macroscopic quantities, the solar module according to the invention or its frame would not yet be adequately described. It is also important that the thermal expansion coefficient of the frame does not exceed a certain maximum value or the coefficient of thermal expansion of the frame differs as little as possible from the thermal expansion coefficient of the material used to cover the solar cells (usually one or more glass panes); since the latter is preferably very low, this results in a maximum upper limit for the thermal expansion coefficient of the frame. It is therefore particularly preferred if these values have only up to α = 50 × 10 ^-6 / K, measured parallel to the module edge.

When using an anisotropic fibrous reinforcing fabric, a low thermal expansion coefficient is only present in the fiber direction. In the case of a peripheral frame, the low thermal expansion coefficient due to the fiber orientation parallel to the glass edge is found. Transversely, the expansion coefficient corresponds to that of the unreinforced material of about 150 · 10 ^-6 / K.

By the special properties, in particular the elasticity, of the polyurethane-comprehensive frame requires the solar module no additional gasket between frame and that of enclosed solar module (although an additional Seal for extreme weather conditions of course can be provided). For improved adhesion, an adhesion primer on the glass or the back construction or the backsheet be applied.

The solar module according to the invention shows sufficient resistance to delamination and moisture tigkeitseintritt. This is ensured by combining a certain macroscopic size-compliant frame material in the sense of the present invention.

Of the Frame of the solar module is usually not only the seal of the solar module to the outside and the increase of his Stability. Rather, it is done via the frame as well the attachment of the solar module to the respective substrate (for Example, house roofs or walls). The solar module Therefore, for example, fasteners, recesses and / or Have holes over which an attachment can take place on the respective underground. Furthermore, the frame pick up the electrical connectors. An afterthought Attachment of a junction box is omitted in this case.

Furthermore, the frame of the solar module preferably has a density of at least 800, in particular of at least 1000 kg / m ³ . By means of such densities given as being preferred, it is stated that the frame is preferably not a foam, but preferably a solid material which has no or, if at all, only extremely few gas inclusions. This is not only favorable for the stability of the frame but for its tightness.

Farther it is possible that the frame of the solar module is isotropic and / or anisotropic fillers, wherein anisotropic and in particular needle-like and / or fibrous Fillers are particularly preferred.

• a) organischen Verbindungen, die halogeniert, phosphorhaltig oder stickstoffhaltig sind und
• b) anorganischen Phosphorverbindungen, anorganischen Metallhydroxiden und anorganischen Borverbindungen.

In the context of the present invention, fillers are understood as meaning organic and / or inorganic compounds, preferably organic and / or inorganic compounds, apart from

• a) organic compounds which are halogenated, phosphorus-containing or nitrogen-containing, and
• b) inorganic phosphorus compounds, inorganic metal hydroxides and inorganic boron compounds.

• 1) die Fasern parallel zur Belastungsrichtung (z. B. parallel zu den Kanten) ausgerichtet sind
• 2) ein großes Länge/Durchmesser-Verhältnis der Fasern vorliegt (je anisotroper desto besser die Verstärkung in Faserrichtung)
• 3) eine Schlichte den Kontakt Faser-Matrix dauerhaft sicherstellt.

The compound groups enumerated under a) and b) are preferably counted among the flame retardants for the purposes of the present invention. The advantage of anisotropic fillers lies in the orientation and the resulting low thermal expansion and shrinkage values. Good properties in the context of the invention are achieved if:

• 1) the fibers are aligned parallel to the loading direction (eg parallel to the edges)
• 2) there is a large length / diameter ratio of the fibers (the more anisotropic the better the reinforcement in the fiber direction)
• 3) A sizing durably ensures the contact fiber matrix.

The Amount of fillers included in the scope is preferred in a range of 10 to 30% by weight, more preferably in one Range of 15 to 25 wt .-%, based on the weight of the polyurethane. Within these areas, those deemed important above macroscopic sizes particularly favorable Values.

Height Reinforcement contents of filled polyurethanes can be in addition to the R-RIM process, for example, with a Fasersprühverfahren or the so-called S-RIM method (S = Structual). In fiber spraying, a fiber-polyurethane mixture is applied the desired location sprayed into the tool. Subsequently closes the tool and the PUR system reacts. The S-RIM process becomes a preformed (continuous) fiber structure inserted in the (frame) tool and then in the still open or already closed tool injected the PUR reaction mixture. This also allows high moduli of elasticity and lower thermal expansion values achieve.

Further is the production of a frame with high fiber content after the RTM method (Resin Transfer Molding) possible, in which again a fiber structure inserted into a tool with vacuum is impregnated.

at Lower filler contents according to current knowledge the danger that the macroscopic invention Properties of the frame can not be achieved.

Prefers If the fillers are synthetic or natural, especially mineral fillers. Most preferably, the fillers are the following Group selected: Mica, platelet and / or fibrous Wollastonite, glass fibers, carbon fibers, aramid fibers or mixtures thereof. fibrous Wollastonite is preferred among these fillers since It is cheap and well available.

Prefers the fillers also have a coating, in particular an aminosilane-based coating. In this case the interaction between the fillers increases and the polymer matrix. This has better usage properties Result, since the coating permanently fiber and polyurethane matrix coupled.

Prefers includes the scope of the solar module according to the invention at least one flame retardant. Under flame retardants in the sense In particular, organic compounds are used in the present invention (in particular halogenated, phosphorus-containing, for example tricresyl phosphate, Tris-2-chloroethyl phosphate, tris-chloropropyl phosphate and tris-2,3-dibromopropyl phosphate, and nitrogen-containing organic compounds) as well as inorganic Phosphorus compounds (for example red phosphorus, ammonium polyphosphate), inorganic metal hydroxides (for example aluminum trihydroxide, Alumina hydrate, ammonium polyphosphate, sodium polymetaphosphate or amine phosphates, e.g. B. melamine phosphates) and inorganic boron compounds (For example, boric acid, borax) understood.

Examples of commercially available flame retardants, which can be used in the present invention are, for example: Disflamoll ^® DPK (diphenyl) Levagard ^® DMPP (Dimethyl) Levagard ^® PP (Tris (2-chloroisopropyl) phosphate), melamine, Exolit ^® AP 422 (a free-flowing, powdery sparingly sparingly soluble in water Ammoniumpolyphsophat the formula (NH ₄ PO ₃ ) _n with n = 20 to 1000, especially 200 to 1000), Apyral ^® (AL (OH) ₃ ).

When Flame retardant particularly preferred is melamine.

Prefers is that the frame of the solar module both fillers as well as flame retardants. Due to these two ingredients result in sufficient mechanical properties (elongation at break, Modulus of elasticity and thermal expansion coefficient, see above), wherein the solar module at the same time sufficient flame retardant properties which, for example, as a roof module for use required are.

• a) Der Rahmen des Solarmoduls umfasst Füllstoffe in einer Menge von 10 bis 15 Gew.-% und Flammschutzmittel in einer Menge von 10 bis 15 Gew.-%.
• b) Der Rahmen des Solarmoduls umfasst Füllstoffe in einer Menge von 10 bis 20 Gew.-% und Flammschutzmittel in einer Menge von 5 bis 7 Gew.-%.

In the ratio of fillers to flame retardants, two alternatives have been found to be particularly preferred:

• a) The scope of the solar module comprises fillers in an amount of 10 to 15 wt .-% and flame retardants in an amount of 10 to 15 wt .-%.
• b) The scope of the solar module includes fillers in an amount of 10 to 20 wt .-% and flame retardants in an amount of 5 to 7 wt .-%.

By the slightly higher proportion of fillers in alternative b) result in slightly better mechanical properties than alternatives a) - but at the expense of flame retardant properties of the frame surrounding the solar module. It is therefore still preferred - in particular in alternative b) - that the frame is an outer flame retardant layer comprises. The outer flame retardant Layer or its chemical precursor is preferred applied to the frame of the solar module or presented in a mold, in which then the solar module is produced (The last alternative is also referred to as a so-called in-mold coating process).

The outer one Flame retardant layer preferably has a thickness in a range from 0.01 to 0.06 mm. Particular preference is given to thicknesses in one Range from 0.03 to 0.06 mm. Below this range are the Flame retardant properties of the outer flame retardant Layer not sufficient. Larger layer thicknesses go along with higher production costs.

In A second embodiment is the basis of the invention underlying task solved by a method for manufacturing a solar module according to the invention with a Frame, which is characterized in that the frame by RIM, R-RIM, S-RIM, RTM, spraying or casting formed becomes.

conditioned The manufacturing process used may be revealed that the macroscopic sizes discussed above the frame is not necessarily constant (so could For example, a higher density results at one point than at others). The upper or lower limits discussed here are to be understood in this context as meaning that they are then in the Funds over the whole framework are not exceeded or fall below.

Even with the use of fibrous fillers, it has been shown during the production of the frame via the R-RIM method that the macroscopic sizes do not extend beyond the frame are constant, because of the process, a certain preferred direction of the fibers as it flows into the mold and the macroscopic sizes depend on the orientation of the fibrous fillers in the polymer matrix.

at The production of polyurethane solar module frames are polyisocyanates used. The polyisocyanates used are to (cyclo) aliphatic or aromatic polyisocyanates. Prefers it is tolylene diisocyanate, di- and / or polyisocyanates of the diphenylmethane series, which have an NCO content of 28 to 50% by weight exhibit. These include liquid at room temperature and optionally modified mixtures of 4,4'-diisocyanatodiphenylmethane with 2,4'- and, to a lesser extent, optionally 2,2'-diisocyanatodiphenylmethane. Also suitable at room temperature are liquid polyisocyanate mixtures the Diphenylmethanreihe, in addition to the isomers mentioned their contain higher homologs, and those known in the art Obtained by phosgenation of aniline / formaldehyde condensates are. Also urethane or carbodiimide groups and / or allophanate or biuret-modified modification products of these di- and polyisocyanates are suitable. Also suitable are NCO prepolymers with an NCO content of 10 to 48 wt .-%. They will be from the aforementioned Polyisocyanates and polyether polyols having a hydroxyl number of 6 to 112, polyoxyalkylene diols having a hydroxyl number of 113 to 1100 or alkylenediols having a hydroxyl number of 645 to 1850 or mixtures thereof.

to Formation of the polyurethane are preferably aromatic isocyanate components based on MDI (diphenylmethane diisocyanate), particularly preferred NCO prepolymers used.

at The production of the solar module frame made of polyurethane will also Polyol formulations used. These contain besides at least a polyhydroxy compound also chain extenders, Catalysts, fillers, auxiliaries and additives.

The polyhydroxy compounds are preferably polyhydroxypolyethers which can be prepared in a manner known per se by polyaddition of alkylene oxides onto polyfunctional starter compounds in the presence of catalysts. The polyhydroxy polyethers are preferably prepared from a starter compound having on average 2 to 8 active hydrogen atoms and one or more alkylene oxides. Preferred starter compounds are molecules having two to eight hydroxyl groups per molecule, such as water, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,4-butanediol, 1,6-hexanediol, triethanolamine, glycerol, trimethylolpropane, pentaerythritol, sorbitol and sucrose. The starter compounds may be used alone or in admixture. The polyols are prepared from one or more alkylene oxides. Preferred alkylene oxides are oxirane, methyloxirane and ethyloxirane. These can be used alone or in a mixture. When used in admixture, it is possible to react the alkylene oxides randomly and / or in blocks. Also suitable are those relatively high molecular weight polyhydroxypolyethers in which high molecular weight polyadducts or polycondensates or polymers in finely dispersed, dissolved or grafted form are present. Such modified polyhydroxyl compounds are z. B. obtained when polyaddition reactions (eg., Reactions between polyisocyanates and amino functional compounds) or polycondensation reactions (eg., Between formaldehyde and phenols and / or amines) in situ in the hydroxyl-containing compounds run (such as in DE-AS 1 168 075 described). Also by vinyl polymers modified polyhydroxyl compounds, as described, for. By polymerization of styrene and acrylonitrile in the presence of polyethers (e.g. U.S. Patent 3,383,351 ) are suitable for the process according to the invention as Polyolhydroxypolyolkomponente. Representatives of said polyol are z. In the Plastics Handbook, Volume VII "Polyurethane", 3rd edition, Carl Hanser Verlag, Munich / Vienna, 1993, pages 57-67 and pages 88-90 described. One or more polyhydroxy polyethers having a hydroxyl number of from 6 to 112, preferably from 21 to 56, and a functionality of from 1.8 to 8, preferably from 1.8 to 6, are preferably used as the polyhydroxypolyol component.

When Chain extenders in the invention Polyol formulation suitable are those whose average hydroxyl or amine number at 245 to 1850 and their functionality at 1.8 to 8, preferably 1.8 to 4, is located. To give an example are here ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, triethanolamine, glycerol, trimethylolpropane and short chain Alkoxylation. Ethylene glycol and 1,4-butanediol become special preferably used.

The intrinsically slow reaction between isocyanate and hydroxyl groups can be accelerated by the addition of one or more catalysts. In particular, tertiary amines of the known type are suitable, for. Triethylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, N-cocomorpholine, N, N, N ', N'-tetramethylethylenediamine, 1,4-diazabicyclo [2.2.2] octane, N-methyl-N'-dimethylaminoethylpiperazine, N, N-dimethylcyclohexylamine, N, N, N', N'-tetramethyl-1,3-butanediamine, N, N-dimethylimidazole-β-phenylethylamine, 1,2-dimethylimidazole, bis (2-dimethylaminoethyl) ether or 2-methylimidazole. Also, organic metal catalysts such as organic bismuth catalysts, eg. B. bismuth (III) neodecanoate or organic tin catalysts, eg. Tin (II) salts of carboxylic acids such as stannous acetate, stannous octoate, stannous (II) ethylhexanoate and stannous laurate, and the dialkyltin salts of carboxylic acids, z. As dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate or Dioctylzinndiacetat can be used alone or in combination with the tertiary amines. The catalysts may be used alone or in combination. Other representatives of catalysts as well as details of the mode of action of the catalysts are in Plastics Handbook, Volume VII "Polyurethane", 3rd edition, Carl Hanser Verlag, Munich / Vienna, 1993 on pages 104-110 described.

Possibly co-used fillers can be both inorganic as well as organic fillers. As inorganic fillers may be mentioned as examples: platelet and / or fibrous Wollastonites, silicate minerals, such as phyllosilicates (eg. Mica), metal oxides such as iron oxides, pyrogenic metal oxides like aerosils, metal salts like barite, inorganic pigments such as cadmium sulfide, zinc sulfide and glass, glass fibers, glass microspheres, Microglass hollow spheres, u. a. As organic fillers exemplified: organic fibers (such as coal and / or Aramid fibers), crystalline paraffins or fats, powder based of polystyrene, polyvinyl chloride, urea-formaldehyde compounds and / or polyhydrazodicarbonamides (eg from hydrazine and tolylene diisocyanate). It can Also hollow microspheres of organic origin or cork can be used. The organic or inorganic fillers can used singly or as mixtures.

To the auxiliaries and additives which may be present in the inventive Polyol formulation can be used, belong for example, blowing agents, stabilizers, coloring agents, Flame retardants, plasticizers and / or monohydric alcohols.

When Propellants are both physical blowing agents and water used. Physical blowing agents are, for example, 1,1,1,3,3-pentafluoropropane, n-pentane and / or i-hexane. Preferably, water is used. The Propellants can be used alone or in combination become.

When Stabilizers are especially surface-active substances, d. H. Connections used to assist serve the homogenization of the starting materials and optionally are also suitable to regulate the cell structure of the plastics. Mentioned are, for example, emulsifiers, such as the sodium salts of Castor oil sulfates or fatty acids and salts of Fatty acids with amines, foam stabilizers, such as siloxane-oxalkylene mixed polymers, and cell regulators, such as paraffins. As stabilizers come predominantly Organopolysiloxanes for use, which are water-soluble are. These are Polydimethylsiloxanreste, where grafted a polyether chain of ethylene oxide and propylene oxide is.

When coloring agents may be used for coloring Polyurethanes per se known dyes and / or color pigments on an organic and / or inorganic basis, for example iron oxide and / or chromium oxide pigments and pigments on phthalocyanine and / or Monoazo base can be used.

Under Flame retardants in the context of the present invention are in particular organic compounds (in particular halogenated, phosphorus-containing, for example, tricresyl phosphate, tris-2-chloroethyl phosphate, tris-chloropropyl phosphate and tris-2,3-dibromopropyl phosphate, and nitrogen-containing organic Compounds) as well as inorganic phosphorus compounds (for example red phosphorus, ammonium polyphosphate), inorganic metal hydroxides (for example, aluminum trihydroxide, alumina hydrate, ammonium polyphosphate, Sodium polymetaphosphate or amine phosphates, e.g. B. melamine phosphates) and inorganic boron compounds (for example boric acid, Borax) understood.

Examples of commercially available flame retardants, which can be used in the present invention are, for example: Disflamoll ^® DPK (diphenyl) Levagard ^® DMPP (Dimethyl) Levagard ^® PP (Tris (2-chloroisopropyl) phosphate), melamine, Exolit ^® AP 422 (a free-flowing, powdery sparingly sparingly soluble in water Ammoniumpolyphsophat the formula (NH ₄ PO ₃ ) _n with n = 20 to 1000, especially 200 to 1000), Apyral ^® (AL (OH) ₃ ).

When Flame retardant particularly preferred is melamine.

Examples of plasticizers are esters of polybasic, preferably divalent, carbon called acids with monohydric alcohols. The acid component of such esters may be, for. B. derived succinic acid, isophthalic acid, trimellitic acid, phthalic anhydride, tetra- and / or hexahydrophthalic, Endomethylentetrahydrophthalsäureanhydrid, glutaric anhydride, maleic anhydride, fumaric acid and / or dimeric and / or trimeric fatty acids, optionally in admixture with monomeric fatty acids. The alcohol component of such esters may be, for. B. deriving branched and / or unbranched aliphatic alcohols having 1 to 20 C-atoms, such as methanol, ethanol, propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, the various isomers of pentyl alcohol, hexyl alcohol, Octyl alcohol (e.g., 2-ethylhexanol), nonyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, and / or fatty and wax alcohols available from naturally occurring or hydrogenated naturally occurring carboxylic acids. Also suitable as the alcohol component are cycloaliphatic and / or aromatic hydroxy compounds, for example cyclohexanol and its homologs phenol, cresol, thymol, carvacrol, benzyl alcohol and / or phenylethanol. Also suitable as plasticizers are esters of the abovementioned alcohols with phosphoric acid. Optionally, phosphoric acid esters of halogenated alcohols, such as. B. trichloroethyl, are used. In the latter case, a flame retardant effect can be achieved simultaneously with the plasticizer effect. Of course, mixed esters of the above-mentioned alcohols and carboxylic acids can be used. The plasticizers may also be so-called polymeric plasticizers, for. B. polyester of adipic, sebacic and / or phthalic acid. Next are also alkyl sulfonic acid esters of phenol, z. B. Paraffinsulfonsäurephenylester, usable as a plasticizer.

Further, optionally used auxiliaries and / or additives are monohydric alcohols such as butanol, 2-ethylhexanol, octanol, dodecanol or cyclohexanol, which may optionally be used to bring about a desired chain termination with. Further details of the customary auxiliaries and additives are the specialist literature, such as Plastics Handbook, Volume VII "Polyurethane", 3rd edition, Carl Hanser Verlag, Munich / Vienna, 1993, page 104 et seq. refer to.

The outer flame retardant layer can be subsequently applied to the frame of the solar module. But it can also be presented in a form in which then the actual solar module is manufactured. The presentation of a (paint) layer in a mold, followed by its closure and exposure to the actual plastic material is also referred to as a so-called in-mold coating process. Possible compositions of such in-mold coating lacquers are, for example, in DE 38 21 908 C1 and US 5,567,763 disclosed.

In A third embodiment is the basis of the invention underlying task solved by a device for generating electrical energy comprising the inventive Photovoltaic solar module with the above-defined physical Properties of the frame.

embodiments

The The following examples illustrate the production of different composite Frame materials and their comparison with each other.

Inventive example:

With the R-RIM process, plate-shaped Bayflex ^® moldings were produced on a Laborkolbendosiermaschine.

The Bayflex ^® system Bayflex ^® VP was used. PU 51BD11 / Desmodur ^® VP. PU 18IF18 with 20% by weight (based on the finished polyurethane elastomer) of a fibrous wollastonite reinforcing material of the type Tremin 939.955 from Quarzwerke, Frechen.

• * – parallel zur Kante des Moduls
• ** – senkrecht zur Kante des Moduls

The plates had the dimensions 200 × 300 × 3 mm ³ . From these plates standard test pieces were punched out according to the respective test standards. The following material properties were determined: Density: 1.25 g / cm ³ DIN EN ISO 845 Tensile E modulus: (in the fiber direction *) 64 N / mm ² DIN EN ISO 37 Tensile modulus of elasticity (transverse to the fiber direction **) 44 N / mm ² DIN EN ISO 37 Elongation at break: (in the fiber direction *) 320% DIN EN ISO 37 Elongation at break: (transverse to grain direction **) 350% DIN EN ISO 37 Shrinkage: (in the fiber direction *) 0.4% (measured in accordance with ISO 294-4) Shrinkage: (across the grain **) 1.0% (measured in accordance with ISO 294-4) Thermal expansion coefficient: (in the fiber direction *) 40 × 10 ^-6 / K DIN 53752 coefficient of thermal expansion: (transverse to fiber direction **) 160 × 10 ^-6 / K DIN 53752

• * - parallel to the edge of the module
• ** - perpendicular to the edge of the module

Comparative Examples:

a) Solid, unfilled elastomer Bayflex ^® VP. PU 81BD03 / Desmodur ^® 0833 BMS AG Density: 1.13 g / cm ³ DIN EN ISO 845 Train modulus: 21 N / mm ² DIN EN ISO 37 Elongation at break: 200% DIN EN ISO 37 Shrinkage: 1.7% (measured in accordance with ISO 294-4 ) thermal expansion coefficient: 190 × 10 ⁶ / K DIN 53752

Comparative Example a) is not suitable as a frame material in the context of the present invention, since the polyurethane has in particular a too high thermal expansion coefficient. b) Microcellular, hard RIM material Baydur ^® 110 (Baydur VP ^®. PU 1498 Desmodur ^® VP. 26Ik01 PU, without filler / reinforcing agent) of Bayer Material Science AG. Density: 1.10 g / cm ³ DIN 53479 Train modulus: 1700 N / mm ² DIN 53455 Elongation at break: 14% DIN 53455 Shrinkage: 0.5-0.8% (measured in accordance with ISO 294-4 ) thermal expansion coefficient: 90 × 10 ^-6 / K DIN 53752

Comparative example b) is not as a frame material in the context of the present invention suitable because the polyurethane in particular a too low elongation at break having.

The The following examples illustrate the production of different composite Frame materials and their behavior in various fire tests.

With the R-RIM process, plate-shaped Bayflex ^® molded body were prepared. Furthermore, polyurethane frames with the same materials were sprayed around glass laminates. The glass laminates were solar glass panes with a back-glued foil composite, the real photovoltaic elements was simulated and thus used to simulate a real solar module. Mechanical tests and fire tests were carried out on the mold plates and solar module models. The results are summarized in Table 1.

The Bayflex ^® system Bayflex ^® VP was used. PU 51BD11 / Desmodur ^® VP. PU 18IF18 (invention) and as a comparative example, the Bayflex ^® system VP. PU 81BD03 / Desmodur ^® VP. PU 0833 with different reinforcing and flame retardant shares. The reinforcing material used was fibrous wollastonite of the type Tremin 939.955 from Quarzwerke, Frechen. As a flame retardant on the one hand, finely crystalline powdered melamine (2,4,6-triamino-1,3,5-triazine) from BASF AG was used. On the other hand, an in-mold coating varnish, which also has flame retardancy, was used. The product bomix PUR-IMC VP 5780006 was used together with the hardener 27/77 from bomix Chemie GmbH, Telgte.

The mold plates were made with the amounts of reinforcing agent and flame retardant (weight percent based on the weight of the part by weight) given in the table and had the dimensions 200 × 300 × 4 mm ³ .

at the application of the in-mold coat was in the open Form first the release agent bomix LC7 / A9807-7, the company bomix Chemie GmbH, Telgte sprayed on. Subsequently was using a spray gun FSP-FP-HTE 1.5 Schneider Druckluft GmbH, Reutlingen a paint layer (100 parts bomix PUR-IMC VP 5780006 and 25 parts hardener 27/77) evenly sprayed on the mold walls. After a ventilation time of 30 seconds, the mold was closed and with a high-pressure piston dosing injected the reactive Poyurethan mixture. According to the safety data sheet bomix GmbH is the used in-mold-coat to a provided with inorganic pigments and dissolved in esters Polyurethane resin, wherein the coatable paint u. a. the following compounds comprise: about 47% butyl acetate, about 10% Triethyl phosphate, about 6% 2,5-pentanedione and about 5% methoxypropyl acetate (In% by weight).

On the mold plates - and in the further on the solar module frame - was realized a paint layer thickness of 0.03 mm.

From the mold plates standard test pieces were punched out according to the respective test standards. The determination of the tensile modulus and the elongation at break in each case in the fiber direction was carried out according to DIN EN ISO 37.

The fire test on strip-shaped samples from the mold plates was carried out in accordance with the Standard UL 94 , The UL 94 is a common pre-test to characterize materials with regard to their fire behavior. In this case, the afterburning time was measured after the test piece was exposed to a flame for 10 seconds and the flame was removed. A flame was applied twice in each case. The goal is an afterburning time of less than 10 seconds.

In the production of the solar module frame was proceeded analogously. The solar module models had the lateral dimensions of 1300 × 800 mm ² with a laminate thickness of 6 mm. The surrounding polyurethane frame had an average thickness of 12 mm.

Fire tests were based on the solar module models produced in this way DIN 4102-7 carried out. For this purpose, two solar module models were screwed side by side on a metallic framework at an angle of 45 ° and a standard set of fire was placed on the horizontal and vertical frame area. The fire protection was based on DIN EN 13501-5 with regard to the vertical and horizontal spread of fire emanating from the fire rate. The aim is to minimize fire propagation in the horizontal and vertical directions.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 4830038 [0013]
• US 5008062 [0013]
• - DE 3737183 A1 [0016]
• - DE 102005032716 A1 [0017, 0024]
• - DE 1168075 [0055]
• - US 3383351 [0055]
• - DE 3821908 C1 [0068]
• US 5567763 [0068]

Cited non-patent literature

• - IEC 61215 [0008]
• - IEC 61730 [0008]
• - DIN 4102-7 [0019]
• - Kunststoff-Handbuch, Volume VII "Polyurethane", 3rd edition, Carl Hanser Verlag, Munich / Vienna, 1993, pages 57-67 and pages 88-90 [0055]
• - Kunststoff-Handbuch, Volume VII "Polyurethane", 3rd edition, Carl Hanser Verlag, Munich / Vienna, 1993 on pages 104-110 [0057]
• - Kunststoff-Handbuch, Volume VII "Polyurethane", 3rd edition, Carl Hanser Verlag, Munich / Vienna, 1993, page 104 et seq. [0067]
• - DIN EN ISO 845 [0073]
• - DIN EN ISO 37 [0073]
• - DIN EN ISO 37 [0073]
• - DIN EN ISO 37 [0073]
• - DIN EN ISO 37 [0073]
• - ISO 294-4) [0073]
• - ISO 294-4) [0073]
• - DIN 53752 [0073]
• - DIN 53752 [0073]
• - DIN EN ISO 845 [0074]
• - DIN EN ISO 37 [0074]
• - DIN EN ISO 37 [0074]
• - ISO 294-4 [0074]
• - DIN 53752 [0074]
• - DIN 53479 [0075]
• - DIN 53455 [0075]
• - DIN 53455 [0075]
• - ISO 294-4 [0075]
• - DIN 53752 [0075]
• - DIN EN ISO 37. [0083]
• - Standard UL 94 [0084]
• - UL 94 [0084]
• - DIN 4102-7 [0086]
• - DIN EN 13501-5 [0086]

Claims (19)

Photovoltaic solar module with a completely or partially encircling frame, made of polyurethane, characterized in that the frame has an elongation at break of at least 50%, an modulus of elasticity of at least 30 N / mm ² and a thermal expansion coefficient of up to α = 80 · 10 ^{- 6} / K, wherein the modulus of elasticity and the thermal expansion coefficient are measured parallel to the module edges. Solar module according to claim 1, characterized that the frame has an elongation at break of at least 80, in particular at least 100%. Solar module according to one of claims 1 or 2, characterized in that the frame has an E-modulus of at least 40, in particular at least 60 N / mm ² , especially at least 70 N / mm ² , in each case measured parallel to the module edges. Solar module according to one of claims 1 to 3, characterized in that the frame has a thermal expansion coefficient of up to α = 50 · 10 ^-6 / K, in each case measured parallel to the module edges. Solar module according to one of claims 1 to 4, characterized in that the frame has a density of at least 800, in particular of at least 1000 kg / m ³ . Solar module according to one of claims 1 to 5, characterized in that the frame is isotropic and / or anisotropic Includes fillers. Solar module according to one of claims 1 to 6, characterized in that the frame fillers in one Amount of 10 to 30, in particular from 15 to 25 wt .-%, based on the weight of the polyurethane elastomer. Solar module according to one of claims 6 or 7, characterized in that the frame is synthetic or natural, especially mineral fillers. Solar module according to one of claims 6 to 8, characterized in that the fillers are selected from the group, the mica, platelet and / or fibrous Wollastonite, glass fibers, carbon fibers, aramid fibers or mixtures thereof includes. Solar module according to one of claims 6 to 9, characterized in that the fillers are a coating, in particular have an aminosilane-based coating. Solar module according to one of claims 1 to 10, characterized in that the frame at least one flame retardant includes. Solar module according to one of claims 6 to 10 and according to claim 11, characterized in that the frame Fillers in an amount of 10 to 15 wt .-% and flame retardants in an amount of 10 to 15% by weight. Solar module according to one of claims 6 to 10 and according to claim 11, characterized in that the frame Fillers in an amount of 15 to 20 wt .-% and flame retardants in an amount of 5 to 7% by weight. Solar module according to claim 13, characterized that the frame is an outer flame retardant layer includes. Solar module according to claim 14, characterized in that that the outer flame-retardant layer has a thickness in a range of 0.01 to 0.06 mm. Process for producing a solar module according to one of Claims 1 to 15, characterized draws that the frame is formed by RIM, R-RIM, S-RIM, RTM, spraying or casting. Method according to claim 16, characterized in that that is an aromatic isocyanate component to form the polyurethane starts. Method according to one of claims 16 or 17, characterized in that the outer flame-retardant Apply layer to the frame of the solar panel or you in a form in which one manufactures the solar module. Device for generating electrical energy comprising the photovoltaic solar module according to any one of claims 1 to 15.