Photovoltaic space module

Abstract

Photovoltaic space module (1) with a) a photovoltaic element (3) and b) a spacecraft membrane (2) with a substrate (5) made of a fluoropolymer and a silicon oxide layer (6; 7), wherein c) the photovoltaic element (3) is glued to the spacecraft membrane (2) and d) a cross-section of the spacecraft membrane (2) da) the silicon oxide layer (6) to which the photovoltaic element (3) is adhered, db) the substrate (5) made of the fluoropolymer, dc) a further silicon oxide layer (7) and dd) has an ITO layer (9) or a titanium oxide layer (19), e) wherein a silicon oxide layer (6, 7) is bonded to each of the two sides of the substrate (5), and the silicon oxide layer (6), which is arranged on the side of the substrate (5) facing the photovoltaic element (3), forms an adhesive interface (8) which enables or improves the adhesion of an adhesive layer (4) by means of which the photovoltaic element (3) is bonded to the spacecraft membrane (2), and an ITO layer (9) is bonded to the outside of the silicon oxide layer (7) on the side of the substrate (5) facing away from the photovoltaic element (3).

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a photovoltaic spacecraft module. STATE OF THE ART

[0002] On the website: http: / / www.sheldahl.com / sites / default / files / Documents / ShieldingMaterials / RedBook.pdf, on the one hand, adhesive tapes are offered that already have a coating of an acrylic adhesive and have a width in the range of 1 to 4 inches, and can be rolled up into a roll. A first such adhesive tape has, in addition to the adhesive layer, an ITO layer, a carrier film made of FEP, and a layer of silver or Inconel (a registered trademark of Special Metals Corporation), whereby the thickness of the layers is much smaller than the thickness of the carrier film.

[0003] This adhesive tape is designed for application to a structure to influence heat transfer. The adhesive tape can be applied to blankets to seal edges or to repair ribs in the outer layers. The adhesive tape can also be perforated. Another adhesive tape has, in addition to the adhesive layer, only an FEP layer and a reflective layer made of silver or Inconel. This adhesive tape is also applied to a structure to influence heat transfer and can be perforated. The adhesive tape can have a protective layer that can be removed after application to protect the adhesive tape from damage during use and application. The reflective behavior can be made diffuse by embossing the reflective layer. Alternatively, an aluminum layer can be used instead of the silver or Inconel layer.The website also suggests adhesive tapes in which an ITO layer is arranged on one side of an FEP layer, while on the other side of the FEP layer there is a layer of silver or Inconel, which in turn is coated with the adhesive layer.

[0004] On the other hand, the website also discloses large-area foil pieces, which can, for example, have a length of 3 m and a width of 1.22 m. In such a foil piece, one side of an FEP layer is coated with an ITO layer, while the other side of the FEP layer is coated with a silver layer or an Inconel layer. Such foil pieces can also be perforated. If a foil piece is to be used as a so-called back-surface mirror, in which reflection occurs not on the side of the foil piece directly facing the radiation source, but on a second reflective surface of a foil layer located within the foil piece, an FEP layer can be coated with a silver layer or an Inconel layer on the side facing away from the radiation source. This results in low solar absorptivity and high emissivity.This piece of film can also be perforated and provided with a protective layer. Alternatively (if otherwise designed appropriately), the reflective layer bonded to the FEP layer can be an aluminum layer.

[0005] DE 10 2007 041 410 B4 discloses a sail foil for a solar sail. The sail foil has an external titanium dioxide layer on the front, followed by a silicon dioxide layer and an aluminum layer. These three layers are vapor-deposited onto a carrier foil. Preferably, these three layers are vapor-deposited on both sides of the carrier foil. The carrier foil is made of polyimide or another polymer material. It is also possible for the aluminum layer itself to form the carrier foil. The selected layer structure is intended to increase the reflectivity of the sail foil, thereby increasing the propulsion effect caused by the sun's radiation pressure. Furthermore, the titanium dioxide layer is intended to make the outer surface of the sail foil particularly resistant to degradation of the thermo-optical properties and increase its suitability for space travel. The titanium oxide layer also acts as an antistatic coating.

[0006] Publication WO 2012 / 135309 A2 discloses a protective film for protecting the supporting structure of a lighter-than-air aircraft, such as a zeppelin or a hot-air balloon, in which a very thin and lightweight skin forming the supporting structure is to be protected by a very thin protective film. The protective film can provide protection against corrosion, protection against ultraviolet radiation, physical protection, influence gas permeation, or influence thermal properties. Various materials and additives can be used in the protective film to influence the desired protective effect. Polymer materials are used in the protective film to influence strength and flexibility.If an outer polymer layer is used in the protective film, this polymer layer can reflect or absorb ultraviolet radiation, preventing the ultraviolet radiation from reaching the underlying substrate to be protected. Protective films of this type can also be used to protect against ozone, atomic oxygen, or other corrosive environments. On the other hand, by using a polymer layer in the protective film, the emission rate of electromagnetic radiation can be increased without increasing the absorption rate of the electromagnetic radiation, thereby controlling heating due to the radiation. WO 2012 / 135309 A2 proposes that the protective film comprise a base layer and an outer layer directly bonded to the base layer. The base layer comprises a soluble polyimide polymer. The base layer has a thickness of less than 12 µm.The outer layer is multilayered, comprising a fluorinated polymer layer, a dielectric layer, at least one metallic layer, a metalloid layer, and / or multiple dielectric layers. The dielectric layer should have a layer thickness that varies by no more than 3%. The outer layer may contain additives. The envelope of the zeppelin or hot-air balloon must be impermeable to the gas contained therein, particularly helium or hydrogen. The supporting structure, which forms the envelope of the aircraft, should be sufficiently strong to ensure a service life of at least one week, preferably at least one month, one year, or ten years or more.The functions of the support structure, on the one hand, and the protective film, on the other, are divided such that the substrate provides mechanical strength, while the protective film increases service life due to environmental influences (UV radiation, ozone, etc.). If the protective layer is intended to ensure protection against ultraviolet radiation, it can comprise polyimide, for which purpose a layer thickness of 1 µm to 5 µm is preferably used. It is also possible for the protective film to contain reflective pigments in the form of titanium dioxide, with the titanium dioxide preferably encapsulated in silicon dioxide to prevent the release of free radicals from the titanium dioxide upon exposure to ultraviolet radiation.

[0007] By using titanium dioxide encapsulated in silicon dioxide in a polyimide matrix, the thickness of the protective film can be reduced by a factor of five while maintaining the desired level of protection. Dielectric components of the protective layer are intended to provide protection against ozone. Protection against atomic oxygen is also intended to be ensured using dielectric components, silicon dioxide, metals such as gold or aluminum, or a special polyimide. It is also possible to provide protection against electrostatic discharge using an ITO layer.

[0008] WO 2019 / 133354 A1 also discloses a protective film for a surface of a supporting structure, which is a missile. The protective film comprises a layer of a cross-linked polymer composition with a removable porous layer arranged thereon and another porous layer arranged within the layer of the cross-linked polymer composition. The supporting structure to which the protective film is to be applied can be a fiber-reinforced composite component. A refined surface finish can be provided by means of the protective film. The protective film is to have a tear-off outer layer, which is said to be advantageous for the production process of the fiber-reinforced composite component. Silicon, siloxanes, aluminum oxide, or metals can be used in the surface to improve the protective effect. Fluoroplastics, however, can be used in the tear-off outer layer.

[0009] US 2016 / 0152353 A1 discloses a thermal barrier layer that can be applied to a support structure, in this case the surface of an airframe, satellite, or rocket, to enable the reflection of sunlight, thereby preventing a temperature increase. An infrared radiation layer is intended to emit infrared light. The infrared radiation layer comprises a cross-linked fluorine material. The infrared radiation layer can be reinforced with a polyimide layer. A reflective metallic layer (Al, Ag, Au) is applied to the side facing the surface of the support structure, while a layer of ITO or TiO2 can be applied to the side facing away from the surface to protect against electrostatic discharges.

[0010] US Pat. No. 5,312,685 A discloses a protective layer for a support structure with a polymeric surface or a surface made of another organic material to protect the surface against oxidation by atomic oxygen. The surface is the surface of a spacecraft moving in low-Earth orbit. The protective layer has a metal oxide layer, which already contributes to preventing atomic oxygen from reaching the substrate made of the polymer material. In addition, a catalyst layer is arranged between the protective layer and the substrate. The catalyst layer ensures that the atomic oxygen partially recombines to form molecular oxygen (O2). Molecular oxygen is less reactive and thus reduces erosion in places where the outer protective layer has defects.

[0011] Further prior art is known from the documents US 2020 / 190787 A1, US 10 815 013 B1 and WO 2020 / 237813 A1. OBJECT OF THE INVENTION

[0012] The invention is based on the object of proposing a photovoltaic spacecraft module which is particularly suitable with regard to - the processing and / or - resistance (e.g. against the space environment and the atomic oxygen present therein) and / or - the thermo-optical properties and / or - protecting the substrate from UV radiation and / or - the long-term resistance (e.g. against atomic oxygen) and / or - the reflection behavior and / or - protection against short-wave UV radiation and / or - the local electrical insulation of electrical components and / or - the avoidance of electrostatic charging and / or - the adhesion of an adhesive and / or - the manufacturing costs and / or - the reinforcement of an edge or rim and / or - the connection of different pieces of film with each other and / or - the layer structure of the spacecraft membrane and the assumption of different functions by the individual layers and / or - improved bondability by increasing adhesion and / or - the application of crack stoppers and / or - the application of electrical components (photovoltaics, harness, diodes, etc.). - the use as a sandwich material in combination with other films is improved. SOLUTION

[0013] The object of the invention is achieved according to the invention with the features of the independent patent claim. Further preferred embodiments of the invention can be found in the dependent patent claims. DESCRIPTION OF THE INVENTION

[0014] The invention relates to a photovoltaic spacecraft module with a spacecraft membrane. The spacecraft membrane is self-supporting and flexible. Self-supporting means that the spacecraft membrane is not glued to a rigid structure of the spacecraft as with the adhesive tape mentioned above, but rather is stretched, unpacked, unfolded, or unrolled at least in one operating state and is only connected to and held by adjacent components in partial areas, edges, or corners. The spacecraft membrane is flexible, allowing it to assume different geometries, in particular a packed state and an unpacked state. To name just a few non-limiting examples, the spacecraft membrane according to the invention can be a component of a solar sail, carry at least one solar cell, be designed as a resistance sail, or be designed as a membrane antenna.

[0015] Conventional spacecraft membranes have a substrate made of a plastic such as polyimide. However, the invention is based on the finding that conventional spacecraft membrane substrates are severely attacked by atomic oxygen, such as that present in low Earth orbits, thus shortening the service life of the spacecraft membrane or requiring additional measures to protect the substrate.

[0016] According to the invention, a substrate made of a “fluorinated plastic” is used for the first time for the self-supporting, flexible spacecraft membrane used in the photovoltaic spacecraft module. Investigations on which the invention is based have shown that the substrate made of the fluorinated plastic has greater resistance to exposure to atomic oxygen. However, even if a person skilled in the art had recognized that the use of a substrate made of a fluorinated plastic was advantageous for this reason, they would not have considered using such a substrate for the present spacecraft membrane. The reason for this is that the person skilled in the art would have determined, when attempting to use a substrate made of a fluorinated plastic, that a connection between the substrate and adjacent layers or components (as is the case, for example,required to ensure additional functions, for edge reinforcement, or for connecting multiple film webs or for applying electrical components, e.g. photovoltaics) is not easily possible. Rather, the technical challenge of bonding a fluoroplastic substrate to another layer or component has only been solved to a limited extent. Approaches include chemical etching processes or plasma treatments to roughen the surface of the fluoroplastic substrate and enable the adhesive to adhere. However, these additional bonding processes are complex, increase costs, and only lead to limited success.

[0017] On the other hand, it is possible that the use of a substrate made of fluorinated plastic provides increased resistance to short-wave UV radiation (especially vacuum ultraviolet radiation).

[0018] According to the invention, it is proposed for the first time that the spacecraft membrane used in the photovoltaic spacecraft module has at least one silicon oxide layer, which is preferably directly bonded on one or both sides to the substrate made of a fluorinated plastic. The silicon oxide layer can have any desired thickness, for example a thickness of 10 nm to 100 nm. The silicon oxide layer can serve, on the one hand, to increase the resistance of the substrate with respect to atomic oxygen. Alternatively or cumulatively, it is possible for the silicon oxide layer to ensure protection of the substrate and the spacecraft membrane with respect to short-wave UV radiation. Alternatively or cumulatively, it is further possible for the silicon oxide layer to provide a type of adhesion promoter for further layers, components, an adhesive, or a type of adhesive interface.The silicon oxide layer can be firmly bonded to the fluorinated plastic substrate. The outer side of the silicon oxide layer, facing away from the substrate, can then be used to attach or bond additional layers or components.

[0019] For the fluorinated plastic from which the substrate is made, there are the following options: a) The fluorinated plastic can be a fluoropolymer based on fluorocarbons with multiple carbon-fluorine bonds. In this case, a large portion of the hydrogen can be replaced with fluorine, resulting in high chemical and thermal stability. This can also be referred to as fluorination or a fluorinated plastic, although not all organic compounds need to be replaced with fluorine. b) It is possible that an FEP (tetrafluoroethylene-hexafluoropropylene copolymer) is used. c) A mix of fluoropolymers can also be used, in particular THV (terpolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride).

[0020] If resistance to atomic oxygen and use at high temperatures are paramount, pure fluoropolymers may be advantageous in some cases. In this case, the properties can be adjusted by blending or layering with other plastics. In particular, this can be achieved by improving mechanical properties, lowering the melting point, and / or influencing the viscosity for industrial processing.

[0021] Preferably, the fluorinated plastic is transparent, so that it is completely see-through or at least translucent. The spacecraft membrane formed with the substrate can then be transparent or opaque, so that the additional layers are then transparent or opaque.

[0022] According to the invention, the substrate is coated on at least one side with an ITO layer and / or a titanium oxide layer. ITO refers to indium tin oxide, a semiconducting material that is largely transparent in visible light. Such a layer can have any thickness, for example, in the range from 10 nm to 100 nm. Such a layer can serve as an antistatic coating. Alternatively or cumulatively, such a layer can also serve as an adhesive interface. According to one proposal of the invention, a silicon oxide layer can be arranged directly between the substrate, on the one hand, and the ITO layer or the titanium oxide layer, on the other.

[0023] If the spacecraft membrane used according to the invention in the photovoltaic spacecraft module is intended to reflect radiation, the substrate can be coated on at least one side with an aluminum and / or silver layer. The aluminum or silver layer can form an outer side of the spacecraft membrane. However, it is also possible for the aluminum or silver layer to be covered by at least one transparent layer, so that the radiation first passes through this covering transparent layer before being reflected by the aluminum or silver layer.

[0024] The aforementioned silicon oxide layer, the ITO layer, and / or the titanium oxide layer can be used to form an adhesive interface, as explained. In this case, the use of a conventional acrylic or silicone adhesive, which adheres to the provided adhesive interface, may be possible. The use of such an acrylic or silicone adhesive would not be readily possible for direct application to the fluorinated plastic substrate.

[0025] The spacecraft membrane can be formed as any desired flat sheet, for example, rectangular, triangular, or otherwise shaped. Preferably, the spacecraft membrane can be converted into a packed state. In this case, the spacecraft membrane is preferably rolled and / or folded in the packed state. Regarding the possibilities for packing with superimposed rolling and folding, reference is made, for example, to the document DE 10 2017 101 178 A1. DE 10 2016 101 430 B4 also discloses a packed spacecraft membrane with a suitable device for unpacking the spacecraft membrane. During packing, all layers of the spacecraft membrane must be rolled and / or folded, whereby the rolling or folding must not impair the mechanical integrity of the spacecraft membrane.Rigid elements, namely rigid photovoltaic cells, are held on the spacecraft membrane, whereby these are arranged between folds in the area of ​​non-folded portions of the spacecraft membrane.

[0026] According to a further proposal of the invention, the spacecraft membrane has at least one bonded crack propagation inhibition element. The crack propagation inhibition element is designed as a bonded surface element or bonded strip, or has any other planar extension. The crack propagation inhibition element can be bonded to the adhesive interface provided by one of the aforementioned layers, for example, to the ITO layer or the silicon oxide layer. The crack propagation inhibition element is preferably arranged in a region of the spacecraft membrane in which the spacecraft membrane is subjected to maximum stress. Strip-shaped crack propagation inhibition elements can also run at regular or irregular intervals or in a grid-like manner along an outer surface of the spacecraft membrane.The crack propagation prevention elements can be made of any film material (single-layer, multi-layer), for example any plastic or one of the materials mentioned in the present application.

[0027] According to the invention, the spacecraft membrane is used for a photovoltaic space module. (At least) one photovoltaic element, for example a rigid or flexible photovoltaic cell or photovoltaic membrane, is glued to the spacecraft membrane. A spacecraft membrane is used in which a cross-section or one side of the spacecraft membrane has a silicon oxide layer, to which the photovoltaic element and other electrical components such as conductor tracks (harness) and diodes are glued. Furthermore, the cross-section of the spacecraft membrane has a fluoropolymer substrate. A silicon oxide layer is applied to this. On the side facing away from the photovoltaics, a coating system consisting of silicon oxide on the one hand and an ITO or titanium oxide layer on the other is provided. These layers can be all of the layers, or further layers can be arranged between the layers or cover them from the outside.Preferably, the cross-section of the spacecraft membrane consists exclusively of the layers mentioned, which then directly adjoin one another in the order in which they were previously mentioned.

[0028] Such a spacecraft membrane can consist of a single film sheet. However, it is also possible for the spacecraft membrane to comprise multiple film sheets, each designed as a spacecraft membrane as described above. In this case, the individual spacecraft membranes or film sheets are glued together at their edges.

[0029] Advantageous further developments of the invention emerge from the patent claims, the description and the drawings.

[0030] The advantages of features and combinations of several features mentioned in the description are merely exemplary and can be effective alternatively or cumulatively, without the advantages necessarily having to be achieved by embodiments according to the invention.

[0031] With regard to the disclosure content – ​​not the scope of protection – of the original application documents and the patent, the following applies: Further features can be found in the drawings – in particular the illustrated geometries and the relative dimensions of several components to one another, as well as their relative arrangement and operative connection. The combination of features of different embodiments of the invention or features of different patent claims is also possible, deviating from the chosen references of the patent claims, and is hereby encouraged. This also applies to features that are illustrated in separate drawings or mentioned in their description. These features can also be combined with features of different patent claims.Likewise, features listed in the patent claims may be omitted for further embodiments of the invention, but this does not apply to the independent patent claims of the granted patent.

[0032] The number of features mentioned in the patent claims and the description is to be understood as meaning that exactly this number or a greater number than the stated number is present, without the need for the explicit use of the adverb "at least." Thus, for example, if reference is made to one element, this is to be understood as meaning that exactly one element, two elements, or more elements are present. These features may be supplemented by other features or may be the only features of which the respective product consists.

[0033] The reference signs contained in the patent claims do not represent a limitation of the scope of the subject-matter protected by the patent claims. They serve solely to make the patent claims easier to understand. BRIEF DESCRIPTION OF THE CHARACTERS

[0034] In the following, the invention is further explained and described with reference to preferred embodiments shown in the figures. Fig. Figure 1 shows a highly schematic structure or cross-section of a spacecraft membrane, which is a photovoltaic space module. Fig. Figure 2 shows a highly schematic structure or cross-section of a spacecraft membrane. Fig. Figure 3 shows, in a highly schematic manner, a structure or cross-section of a spacecraft membrane for a first embodiment of a reflector for a membrane antenna or a solar sail (this application not being covered by the wording of the patent claims). Fig. Figure 4 shows, in a highly schematic manner, a structure or cross-section of a spacecraft membrane for a second embodiment of a reflector for a membrane antenna or a solar sail (this application not being covered by the wording of the patent claims). FIGURE DESCRIPTION

[0035] Fig. 1 shows a highly schematic layered structure of a photovoltaic space module 1 with a spacecraft membrane 2. The photovoltaic space module 1 has a photovoltaic element 3, which can be a photovoltaic cell and can be rigid or designed as a flexible photovoltaic membrane and can optionally have other components important for the function such as electrical contact (harness) and / or diodes.

[0036] Preferably, several such photovoltaic elements 3 are distributed regularly or irregularly across the spacecraft membrane 2. The photovoltaic element 3 is bonded to the spacecraft membrane 2 via an adhesive layer 4, preferably made of an acrylic or silicone adhesive.

[0037] The spacecraft membrane 2 has a substrate 5, which can also be designed as a carrier layer. The substrate 5 is made of fluorinated plastic, although any of the fluorinated plastics listed above can be used. A silicon oxide layer 6, 7 is bonded to both sides of the substrate 5. The silicon oxide layer 6, which is arranged on the side of the substrate 5 facing the photovoltaic element 3, forms an adhesive interface 8, which enables or improves the adhesion of the adhesive layer 4. On the side of the substrate 5 facing away from the photovoltaic element 3, an ITO layer 9 is bonded to the outside of the silicon oxide layer 7. It is possible for the photovoltaic space module 1 to be composed of several film webs 10a, 10b, 10c, ..., which are bonded together at their edges. The ITO layer 9 can serve as an adhesive interface 11 to enable the bonding of the overlapping edges.The silicon oxide layer 6, 7 can provide UV protection, while the ITO layer 9 can provide an antistatic coating. It is possible to use a titanium oxide layer instead of the ITO layer 9.

[0038] Fig. Figure 2 schematically shows the layered construction of a resistance sail 12 (although this application is not covered by the wording of the patent claims). Here, a silicon oxide layer 6, 7 is bonded to the fluoropolymer substrate 5 on both sides. An ITO layer 9, 13 is connected to this layer in each case. Here, too, several film webs 10a, 10b, 10c, ... can be bonded together. In this case, the outer sides of the ITO layers 9, 13 can form an adhesive interface 11 in the overlap region. It is also possible for the film webs 10 to be reinforced in the region of their edges or an edge. This reinforcement can consist of a folding of the edge, with the folded film regions then being bonded together. In this case, the folded, mutually facing outer sides of the ITO layer 9 or the ITO layer 13 can each form an adhesive interface, which enables bonding.It is also possible that the edge is bonded to a separate reinforcement. It is possible that a titanium oxide layer is used instead of the ITO layer 9,13.

[0039] Fig. Figure 3 shows the use of the spacecraft membrane 2 for a membrane antenna 14 or a reflector thereof or a solar sail 15 (these applications are not covered by the wording of the patent claims). Fig. In the embodiment shown in Figure 3, a silicon oxide layer 6, 7 is applied to the substrate 5, which preferably consists of a fluoropolymer film. The silicon oxide layers 6, 7 are coated on their outer sides with an aluminum layer 16, 17. The aluminum layers 16, 17 ensure the required reflection. Furthermore, the silicon oxide layers 6, 7 can ensure UV resistance, thus ensuring long-term stability.

[0040] Fig.Figure 4 also shows a membrane antenna 14 or a solar sail 15 (although these applications are not covered by the wording of the patent claims), in which the thermo-optical properties are adapted by an oxide coating on the exterior. Here, the aluminum layers 16, 17 are directly adjacent to the fluoropolymer substrate 5. The aluminum layers 16, 17 are each coated externally with silicon oxide layers 6, 7. Alternatively, the aluminum layers 16, 17 can be coated on their exterior sides with a titanium oxide layer 18, 19. The outer oxide layer 6, 7 or 18, 19 can improve the radiation behavior in the infrared range. At the same time, good reflection behavior can be ensured by the inner aluminum layer 16, 17.

[0041] For the illustrated embodiments, the substrate was formed from a single layer of fluorinated plastic. However, it is also entirely possible for the substrate 5 to consist of several laminated layers made of the same or different materials or fluorinated plastics. Preferably, the individual layers then serve to provide different desired properties.

[0042] The exemplary embodiments illustrated in the drawings may comprise only the illustrated and named layers. It is entirely possible that the spacecraft membrane may comprise additional elements such as stiffening elements, electrical wires, eyelets, deployment safety elements, packaging elements, electrical components, reinforcements, intermediate layers, or at least one additional outer layer.

[0043] If a transparent, non-reflective spacecraft membrane made from fluorinated plastic is used, light pollution in the night sky can be reduced. Reflections from reflective spacecraft membranes, especially those coated with aluminum, are clearly visible in the night sky and pose a problem, particularly for astronomy, when launching large constellations with hundreds of satellites.

[0044] The thicknesses of the layers mentioned here can be the same or different. Layers with a thickness of 10 nm to 100 nm, preferably 20 nm to 80 nm or 30 nm to 70 nm, are preferably used.

[0045] Preferably, the spacecraft membrane 2 is bonded to components such as the photovoltaic element, edge reinforcements, adjacent film webs, or other components using an adhesive layer 4 made of an acrylic or silicone adhesive. For example, the substrate 5 can have an inner polyimide film, which is intended to ensure the mechanical strength of the substrate 5. A layer of a fluorinated plastic can then be applied to at least one outer side of the polyimide film. This layer can be vapor-deposited, for example. It is also possible to use a thermoplastic fluorinated plastic, which is then pressed onto the inner polyimide film at high temperature, forming the required bond.

[0046] The invention also encompasses embodiments with a layer system in which a reflector layer (aluminum or silver) is combined with SiO2 and ITO, and this reflector layer is arranged on the substrate 5 made of a fluoropolymer, optionally with further layers on this or the other side of the substrate 5. Such a spacecraft membrane can then be used, for example, for reflector antennas and solar sails (although these applications are not covered by the wording of the patent claims).

[0047] A layer structure of aluminum / fluoropolymer / SiO2 / ITO is also possible, whereby aluminum can also be replaced by silver, whereby this layer structure can preferably be used for a rear surface mirror (although this application is not covered by the wording of the patent claims). LIST OF REFERENCE SYMBOLS 1 photovoltaic space module 2 spacecraft membrane 3 photovoltaic element 4 adhesive layer 5 Substrat 6 Silicon oxide layer 7 Silicon oxide layer 8 Adhesive interface 9 ITO layer 10 film strips 11 Adhesive interface 12 resistance sails 13 ITO layer 14 Membrane antenna 15 solar sails 16 aluminum layer 17 aluminum layer 18 Titanium oxide layer 19 Titanium oxide layer

Claims

[1] Photovoltaic space module (1) with a) a photovoltaic element (3) and b) a spacecraft membrane (2) with a substrate (5) made of a fluoropolymer and a silicon oxide layer (6; 7), wherein c) the photovoltaic element (3) is glued to the spacecraft membrane (2) and d) a cross-section of the spacecraft membrane (2) da) the silicon oxide layer (6) to which the photovoltaic element (3) is adhered, db) the substrate (5) made of the fluoropolymer, dc) a further silicon oxide layer (7) and dd) has an ITO layer (9) or a titanium oxide layer (19), e) wherein a silicon oxide layer (6, 7) is bonded to each of the two sides of the substrate (5), and the silicon oxide layer (6), which is arranged on the side of the substrate (5) facing the photovoltaic element (3), forms an adhesive interface (8) which enables or improves the adhesion of an adhesive layer (4) by means of which the photovoltaic element (3) is bonded to the spacecraft membrane (2), and an ITO layer (9) is bonded to the outside of the silicon oxide layer (7) on the side of the substrate (5) facing away from the photovoltaic element (3). [2] Photovoltaic space module (1) according to claim 1, characterized by that the spacecraft membrane (2) is transparent. [3] Photovoltaic space module (1) according to one of the preceding claims, characterized by that the substrate (5) is coated on at least one side with an aluminum layer (16; 17) and / or a silver layer. [4] Photovoltaic space module (1) according to one of the preceding claims, characterized by that the spacecraft membrane (2) has at least one glued-on crack propagation prevention element.

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