Photovoltaic module

Abstract

Photovoltaic Module (M) comprising a front face (1) and a rear face (3) between which is arranged an encapsulant (2) of photovoltaic cells (20), the module (M) comprising a plurality of strings, each of one or more photovoltaic cells (20), the photovoltaic cell(s) (20) of a string being placed in series along a longitudinal axis of the string, the module (M) further comprising a plurality (10) of stiffeners (11, 12) arranged between the front face (1) and the rear face (3), the plurality (10) of stiffeners comprising at least one longitudinal stiffener (11) placed between the strings of photovoltaic cells (20), so as to extend longitudinally between two strings of photovoltaic cells (20). Figure for the abbreviation: Fig. 3

Description

Title of the invention: Photovoltaic module technical field

[0001] The present invention relates to a photovoltaic module and a method for manufacturing such a photovoltaic module. The photovoltaic module comprises at least one photovoltaic cell embedded in an encapsulating assembly comprising a polymer material and two external faces containing a polymer material or glass. Prior art

[0002] A photovoltaic module comprises photovoltaic cells designed to convert radiant or light energy into electrical energy. Such a photovoltaic module may be subjected, during its use, for example in space, to high thermal stresses, particularly with large temperature cycles. Such thermal stresses can induce deformations such as bending and waviness, which are detrimental to the flatness of the photovoltaic module as well as to its long-term performance.

[0003] For example, international patent WO 2017 / 085017 discloses the use of a lightweight and very rigid back face. This back face consists of a honeycomb core and external faces made of composite materials. It is accompanied by an insulating layer, allowing it to be electrically isolated from the rest of the module. This back face covers the entire surface of the module and is shaped during the lamination of the photovoltaic module. The weight reduction is limited.

[0004] International application WO 2013 / 074224 uses the same principle with a foam core, which does not allow for further reduction of the weight of the back face.

[0005] French patent application FR 3 138 001 describes a method of stiffening the photovoltaic module by adding a composite frame to the outside of the rear face. This frame can be composed of a single layer of composite material or of a sandwich structure with a honeycomb or hollow core and external faces made of composite material.

[0006] Finally, international application WO 2023 / 199005 implements a frame around the perimeter of the module, a frame which may be made of composite material or of a sandwich structure similar to those described above. This frame is integrated into the module during lamination.

[0007] In the last two documents cited, local stiffening of the module is not achieved, but only of its periphery. The part of the module between two strings of cells can remain flexible and still be subject to undulations and deflections.

[0008] Also, there is a need to further mechanically reinforce the photovoltaic modules.

[0009] Furthermore, there is a need for very lightweight photovoltaic modules, particularly for certain terrestrial or extraterrestrial applications.

[0010] Finally, there is also a need to reduce the cost of photovoltaic modules for certain terrestrial or extraterrestrial applications. Summary of the invention

[0011] The present invention meets all or part of this need and thus relates to a photovoltaic module, comprising a front face and a rear face between which is arranged an assembly encapsulating photovoltaic cells, the module comprising a plurality of strings each of one or more photovoltaic cells, the photovoltaic cell(s) of a string being placed in series along a longitudinal axis of the string, the module further comprising a plurality of stiffeners arranged between the front face and the rear face, the plurality of stiffeners comprising at least one longitudinal stiffener placed between the strings of photovoltaic cells, so as to extend longitudinally between two strings of photovoltaic cells.

[0012] The plurality of stiffeners may include in particular several longitudinal stiffeners placed between the strings of photovoltaic cells, so as to extend longitudinally each between two strings of photovoltaic cells.

[0013] The presence of stiffeners increases the rigidity of the photovoltaic module, particularly locally, notably around the photovoltaic cells. The stiffeners reduce deflection during thermal cycling of a photovoltaic module, primarily between the photovoltaic cells. Thus, the photovoltaic module according to the invention is less prone to waviness or deflection during thermal cycling, especially spatial cycling.

[0014] The photovoltaic module according to the invention can, in particular, be configured to withstand several thousand thermal cycles ranging from +120°C to -120°C, for example at atmospheric pressure or, for example, at zero pressure. A cycle can typically last, for example, approximately 1 hour 30 minutes.

[0015] The term 'photovoltaic cell string' refers to an assembly of one or more photovoltaic cells, the photovoltaic cells being connected in series in the string. A string may consist of only one photovoltaic cell. A photovoltaic cell string extends along a longitudinal axis, the photovoltaic cells of the string following one another along this longitudinal axis, which thus forms a major axis for the string. Description of the invention: Photovoltaic module

[0016] The photovoltaic module as such comprises one or more photovoltaic cells arranged between a front face and a rear face separated by a slice of the photovoltaic module, and which are electrically connected to each other by connecting conductors and which are immersed between two front and rear layers of encapsulation material both forming the encapsulating assembly.

[0017] The photovoltaic module may include, in particular, at least: - a first transparent protective layer forming the front face, for example made of glass, or for example made of at least one polymer material, for example based on multi-layer polymers, - an encapsulating assembly formed by at least one layer comprising at least one polymer-type encapsulating material, for example of a transparent elastomer type, in which photovoltaic cells are encapsulated or coated, and - a second protective layer forming the rear face of the photovoltaic module, for example also made of glass, or for example made of at least one polymer material, for example based on multi-layer polymers defining a non-transparent rear face, called a "backsheet".

[0018] The first transparent protective layer and the second protective layer make it possible to protect the module from external attacks and possibly to stiffen it, in particular in the case where they are made of glass.

[0019] The first transparent protective layer may not be made of glass, but for example, based on one or more polymer materials. It can thus advantageously be lighter. The polymer(s) may be chosen from the following, which is not exhaustive, list: ETFE, ECTFE, PVDF, PU, ​​PC, PI, PEEK, PET, PA.

[0020] The presence of the stiffeners makes it possible to stiffen the photovoltaic module well, even in the presence of one or two polymer-based protective layers, which are less rigid than glass.

[0021] The photovoltaic module may be without a protective glass layer. It may not have any protective glass layer.

[0022] The photovoltaic module further comprises an interconnection consisting, on the one hand, of wires or ribbons, which allow the photovoltaic cells to be connected in series and act as a "highway" for electrons. The set of cells connected together by wires or ribbons is called a string; and on the other hand, of a solder joint that ensures good mechanical and electrical contact between the wire and the cell. This solder joint can be made continuously along the entire wire, or locally, by solder pads.

[0023] Edges of the photovoltaic module, which define its perimeter, can be defined as being formed by the edges of the front and rear faces and the encapsulating assembly. Two opposite edges can be defined, the photovoltaic module being able to have a general rectangular shape. The edges may have a certain thickness, due to the presence of the photovoltaic cells in the encapsulating assembly, so that edges can be defined at the top and bottom edges, on either side of the slice of the photovoltaic module. Encapsulating assembly

[0024] The encapsulating assembly can be formed from at least one front film and one back film comprising at least one polymer-type encapsulating material selected from: acid copolymers, ionomers, poly(ethylene-vinyl acetate) (EVA), vinyl acetals, such as polyvinyl butyrals (PVB), polyurethanes, polyethylenes, such as linear low-density polyethylenes, polyolefin elastomer copolymers, α-olefin copolymers and α-,[3-ethylenic carboxylic acid esters, such as ethylene-methyl acrylate copolymers and ethylene-butyl acrylate copolymers, silicone elastomers and / or elastomers based on crosslinked thermoplastic polyolefin.

[0025] By the term "encapsulating assembly" or "encapsulated", it is to be understood that the plurality of photovoltaic cells is arranged in a volume, for example hermetically sealed with respect to liquids and gases, at least partly formed by at least two films of encapsulating material(s), joined together after lamination to form the encapsulating assembly.

[0026] Indeed, initially, that is to say before any lamination operation, the encapsulating assembly consists of at least two films of encapsulating material(s), between which the plurality of photovoltaic cells is encapsulated.

[0027] However, during the film lamination operation, the encapsulation material films melt to form, after the lamination operation, only one solidified assembly in which the photovoltaic cells are embedded or coated.

[0028] A photovoltaic module may have two protective layers, the first protective layer forming, for example, the front face and made of one or more transparent materials chosen from the following, non-exhaustive list: glass, composite material, plastic, polymer. A photovoltaic module may have a second protective layer forming the rear face and made of one or more materials chosen from the following, non-exhaustive list: glass, composite material, plastic, polymer, metals. If both the first and second protective layers are made of glass, it is called a double-glass module. Alternatively, the first and second protective layers may be made of composite material, plastic, or polymer. Stiffeners

[0029] By 'stiffener', we mean an elongated beam-type element, very rigid in bending.

[0030] The plurality of stiffeners may include at least one longitudinal stiffener, or even several longitudinal stiffeners of the plurality of stiffeners, which may extend longitudinally along the longitudinal axis of the garland, in particular of the garland adjacent to said stiffener.

[0031] The module may be without a stiffener above a photovoltaic cell, so as to avoid the risk of damage to a photovoltaic cell during the lamination of the module during its manufacture.

[0032] One or more stiffeners from the plurality of stiffeners may be arranged between the front face and the encapsulating assembly, in particular one or more longitudinal stiffeners from the plurality of stiffeners may be arranged between the front face and the encapsulating assembly.

[0033] Stiffeners, particularly longitudinal stiffeners, are advantageously positioned on the front face, thereby facilitating the manufacturing process, especially lamination, which can be carried out in a single lamination step. They can, in particular, be placed within the encapsulating assembly, between the front face and the photovoltaic cell(s).

[0034] One or more stiffeners from among the plurality of stiffeners may be arranged between the encapsulating assembly and the rear face; in particular, one or more longitudinal stiffeners from among the plurality of stiffeners may be arranged between the encapsulating assembly and the rear face. They may, in particular, be placed within the encapsulating assembly, between the rear face and the photovoltaic cell(s).

[0035] In one embodiment, the photovoltaic module may include on the one hand one or more stiffeners arranged between the front face and the encapsulating assembly and on the other hand one or more stiffeners arranged between the encapsulating assembly and the rear face.

[0036] One or more stiffeners, particularly longitudinal stiffeners, among the stiffener(s) located between the encapsulating assembly and the rear face can be superimposed with the stiffener(s), particularly longitudinal stiffeners, located between the front face and the encapsulating assembly. Thus, the stiffeners, particularly longitudinal stiffeners, can be stacked one on top of the other. A stiffener located between the encapsulating assembly and the rear face can be placed opposite a stiffener located between the front face and the encapsulating assembly. Such a configuration with the stiffeners stacked one on top of the other provides better mechanical reinforcement of the photovoltaic module.

[0037] The stiffeners, in particular longitudinal ones, can be arranged symmetrically with respect to each other with respect to a plane of symmetry passing through the encapsulating assembly.

[0038] The photovoltaic module may include a reinforcing layer, in particular made of composite material, disposed between the encapsulating assembly and the rear face. The The additional presence of this reinforcing layer improves the rigidity of the photovoltaic module.

[0039] A maximum gap e between the stiffeners and the reinforcement layer The spacing can be between 0 mm (inclusive) and 5 mm, or even between 0 mm (exclusive) and 1 mm, ideally between 100 µm and 500 µm, for example, approximately 300 µm. Maximizing this spacing can be advantageous to further improve the rigidity of the photovoltaic module.

[0040] The reinforcing layer may have high tensile strength, for example, on the order of at least 10 GPa. The reinforcing layer may be configured to retain its mechanical properties up to a temperature of at least 120°C, preferably at least 140°C, or even at least 160°C. The reinforcing layer may have a coefficient of thermal expansion of less than 2 x 10⁻⁵ Kl, or even less than 1.5 x 10⁻⁵ Kl, or even less than 1 x 10⁻⁵ Kl. The reinforcing layer may have a thickness of between 10 µm and 1000 µm, or even between 20 µm and 800 µm, or even between 30 µm and 600 µm, being in particular around 50 µm.

[0041] The reinforcing layer may include fibers embedded in a matrix. The fibers may, for example, be chosen from the following list, which is not exhaustive: glass fibers, carbon fibers, natural fibers, for example hemp, flax, basalt, silicon carbide fibers, polyester fibers. The matrix may, for example, be chosen from the following list, which is not exhaustive: plastic material, for example from polyurethane (PU), polypropylene (PP), epoxy, polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polyamide (PA), an acrylic adhesive, silicone, an epoxy adhesive, a fluorinated polymer, in particular polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), ethylene tetrafluoroethylene (ETFE), ethylene chlorotrifluoroethylene (ECTFE), polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE) and / or fluorinated ethylene propylene (FEP).The material(s) for the fibers and / or matrix may be similar or identical to the material(s) chosen for the stiffener(s), in particular from the same family, as described below.

[0042] The reinforcing layer can advantageously be integrated in a single step in the manufacturing process.

[0043] The reinforcing layer may be smooth, in particular being devoid of relief. It may, in particular, be devoid of bars.

[0044] The reinforcing layer may be opaque. Its placement on the rear face may therefore be advantageous.

[0045] The stiffener(s), in particular the longitudinal stiffener(s), may or may not protrude from the encapsulating assembly.

[0046] The protruding stiffeners can facilitate the attachment of the photovoltaic module to a mounting structure, thus creating preferential attachment points. A portion of a stiffener extending beyond the encapsulating assembly can serve as an attachment point to the mounting structure. Such a configuration can eliminate the need for a frame. The photovoltaic module can be frameless. The stiffeners can be attached to the mounting structure by bolting, riveting, clamping, or bonding, particularly by riveting. Riveting can provide better resistance to spatial thermal cycling and allow for some play to accommodate the expansion and contraction of the photovoltaic module during thermal cycling.

[0047] Alternatively, the stiffener(s) may not protrude from the encapsulating assembly. This can result in a weight reduction for the photovoltaic module.

[0048] The overhang can be of a length 12 between 0 inclusive and 200 mm, or even between 0 exclusive and 180 mm, or even between 1 mm and 160 mm, better between 2 and 140 mm, or even better between 5 and 120 mm, being for example about 50 mm.

[0049] The width of a stiffener can vary in the portion that extends beyond the enclosing assembly; in particular, the width can increase. The width of the stiffener outside the enclosing assembly is then defined as 13. This width 13 can vary between 2 cm and 15 cm, preferably between 3 cm and 13 cm, or even between 4 cm and 10 cm, being, for example, approximately 5 cm. The width can be increased through various geometries, including a right angle, a bevel, or a fillet.

[0050] The photovoltaic module may include one or more transverse stiffeners arranged transversely to the strings of photovoltaic cells. The transverse stiffener(s) may be located between the rows of strings, perpendicular to their longitudinal axis.

[0051] The transverse stiffener(s) can be connected to the longitudinal stiffeners. They can be used to connect the longitudinal stiffeners to each other. The transverse and longitudinal stiffeners can form a stiffening grid for the photovoltaic module.

[0052] The transverse stiffener(s) may or may not protrude from the encapsulating assembly, in particular as described above.

[0053] The transverse stiffeners may not be in contact with each other. The longitudinal stiffeners may not be in contact with each other.

[0054] The photovoltaic module may include one or more longitudinal and / or transverse stiffeners arranged between one or more strings and an edge of the photovoltaic module. This configuration allows the addition of two longitudinal and / or transverse stiffeners on the lateral, upper, and lower edges of the module, so that The stiffeners can cover all the spaces between the garlands as well as the perimeter of the module. The module is thus more rigid.

[0055] With this configuration, the stiffeners can extend beyond the module to create preferred attachment points, as described above. Adding two transverse stiffeners to the upper and lower edges of the module allows for four extensions, and therefore four attachment points. This configuration thus provides better stability of the module relative to the attachment structure.

[0056] In order to minimize the risk of bending or waviness of the photovoltaic module, the stiffeners can preferably fill almost all the space between the strings. Thus, a distance dl between a string and the adjacent stiffener, measured in the plane of the photovoltaic module, can be between 0 mm and 10 mm, or even between 0.5 mm and 8 mm, or even between 1 mm and 3 mm.

[0057] Similarly, the overhang of the photovoltaic module around the strings on the periphery of the latter can preferably be minimized. Thus, a distance d2 between the edge of the photovoltaic module and the edges of the strings or the longitudinal end stiffeners can be between 0.5 mm and 20 mm, or even between 0.7 mm and 15 mm, or even between 0.8 mm and 10 mm, or even better between 0.9 mm and 8 mm, being by being between 1 mm and 4 mm.

[0058] Thus, almost the entire surface of the photovoltaic module can be covered with rigid surfaces, photovoltaic cells, or stiffeners. With such a small overhang of the different layers of the photovoltaic module, the output interconnections of the strings can be exposed.

[0059] The width 11 of a stiffener can be between 2 mm and 50 mm, better between 4 mm and 45 mm, or even between 6 mm and 40 mm, or even between 8 mm and 35 mm, being for example between 10 and 30 mm, being in particular about 20 mm.

[0060] The width 11 of a stiffener is advantageously large enough to allow the stiffeners to provide rigidity to the photovoltaic module, without, however, reducing the surface area of ​​the photovoltaic cells too much. The surface area occupied by the stiffeners need not exceed 50% of the surface area of ​​the photovoltaic module.

[0061] A stiffener, longitudinal or transverse, may have a general elongated shape.

[0062] In cross-section, it can be generally polygonal, rectangular, triangular, circular, semi-circular, elliptical, squircle, or Reuleaux triangle in shape, this list being non-exhaustive. A shape that tapers in cross-section can facilitate the insertion of the stiffener and its integration into the photovoltaic module. Indeed, such a shape allows the front or rear face to completely surround the stiffener, thus smoothing the transition between the parts with and without stiffeners and improving stress distribution.

[0063] A stiffener may include a core, in particular a core made of a lightweight material, the core being covered in particular in whole or in part with a coating, in particular a coating made of a composite material.

[0064] A stiffener is preferably lightweight, so as not to excessively increase the weight of the photovoltaic module. The core can be made of a lightweight material, which can increase the stiffener's flexural rigidity without adding too much weight.

[0065] The coating can be advantageously resistant.

[0066] The stiffener is thus configured to allow rigidity in bending, without necessarily rigidity in tension, while maintaining a high lightness.

[0067] The flexural rigidity is preferably high, in particular greater than 1 GPa, or even greater than 3 GPa, better greater than 5 GPa, or even greater than 7 GPa, or even greater than 10 GPa.

[0068] The core can be in cross-section of a general shape chosen from the following list, which is not exhaustive: polygonal, rectangular, triangular, circular, semi-circular, elliptical, squircles, Reuleaux triangle, this list not being exhaustive.

[0069] The density of the core can be less than 500kg / m3, or even less than 400kg / m3, better less than 300kg / m3, or even less than 200kg / m3, being for example about 100kg / m3.

[0070] The mechanical properties of the core are preferably preserved up to a temperature of at least 120°C, or even at least 130°C, better at least 140°C, or even at least 150°C, for example about 160°C.

[0071] The core can be configured so as not to crush under the pressure of the laminator used to perform the lamination step during the manufacture of the photovoltaic module. The pressure can be at least 300 mbar, or even at least 600 mbar, preferably at least 700 mbar, or even at least 800 mbar, being for example approximately 1 bar.

[0072] The core can have an alveolar structure like a honeycomb, for example in aluminium or other metallic materials, copper, steel for example, this list not being exhaustive.

[0073] The stiffener coating can be in cross-section of a general shape chosen from the following list, which is not limiting: polygonal, rectangular, triangular, circular, this list not being limiting.

[0074] The coating can be made of a composite material. The coating may comprise fibers embedded in a polymer resin matrix.

[0075] The fibers may, for example, be chosen from the following list, which is not exhaustive: glass fibers, carbon fibers, aramid fibers, natural fibers, fibers hemp, flax fibers, basalt fibers, silicon carbide fibers, polyester fibers.

[0076] The matrix can for example be chosen from the following list, which is not limiting: plastic material, polyurethane (PU), polypropylene (PP), epoxy, polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polyamide (PA), polyetheretherketone (PEEK), acrylic glue, silicone, epoxy glue, fluorinated polymer, polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), ethylene tetrafluoroethylene (ETFE), ethylene chlorotrifluoroethylene (ECTFE), polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE) and / or fluorinated ethylene propylene (FEP).

[0077] The composite material of the coating may have high tensile strength, in particular greater than 10 GPa or more.

[0078] The mechanical properties of the coating are preferably maintained up to a temperature of at least 120°C, or even at least 130°C, better at least 140°C, or even at least 150°C, for example about 160°C.

[0079] The composite material of the coating may have a coefficient of thermal expansion less than 2 x 10⁻⁵ Kl, preferably less than 1.8 x 10⁻⁵ Kl, or even less than 1.4 x 10⁻⁵ Kl, for example less than 1 x 10⁻⁵ Kl

[0080] It could be a carbon composite, for example.

[0081] The stiffener structure can be symmetrical, in particular with symmetry with respect to a plane, being in particular symmetrical with respect to its vertical and / or horizontal median planes.

[0082] The thickness of the stiffener can be between 0.5 mm and 50 mm, better between 1 mm and 40 mm, or even between 1.5 mm and 30 mm, or even between 1.7 mm and 25 mm, being for example between 2 and 20 mm.

[0083] The thickness h2 of the core can be between 0.4 mm and 25 mm, better between 1 mm and 20 mm, or even between 2 mm and 15 mm, or even between 3 mm and 12 mm, being for example about 3 mm.

[0084] The thickness hl of the coating can be between 25 pm and 2 mm, better between 35 pm and 1 mm, or even between 40 pm and 700 pm, or even between 50 pm and 500 pm, being for example about 100 pm.

[0085] In another embodiment, the stiffener(s) are single-layer, comprising only one layer of composite material, the fibers and matrix of which may be derived from the same material families as the composite material of the coated core stiffeners, as described above. This single layer may have a thickness h3 which may be between 50 µm and 1000 µm, preferably between 100 µm and 900 µm, or even between 200 µm and 700 µm, or even between 300 µm and 600 µm, being for example approximately 500 µm.

[0086] Such a stiffener can respect the same mechanical properties of the coating of the coated core stiffeners, as described above.

[0087] Such a stiffener structure is particularly effective in addition to a reinforcement layer, in particular made of composite material, on the back face, because in this case, it is the intermediate layers of the photovoltaic module, the encapsulating assembly in particular, that play the role of the core.

[0088] In yet another embodiment, the stiffener(s) may have a very thin web. The web thickness h2 may be between 50 pm and 1000 pm, preferably between 80 pm and 800 pm, or even between 100 pm and 600 pm, or even between 1500 pm and 400 pm, being for example about 200 pm.

[0089] This very thin core can have good rigidity in tension, being in particular greater than 1 GPa, or even greater than 3 GPa, better greater than 5 GPa, or even greater than 7 GPa, or even greater than 10 GPa.

[0090] This very thin core can have a coefficient of thermal expansion less than 2.10-5 Kl, better less than 1.8.10-5 Kl, or even less than 1.4.10-5 Kl, being for example less than 1.10-5 Kl.

[0091] The very thinness of this core means that the lightness criterion expressed for the core of the coated stiffener is not essential here. Kovar or Invar are examples of usable metals.

[0092] Photovoltaic cells may contain silicon, in particular multi- or monocrystalline silicon. Such cells can be less expensive. The use of these cells can thus make it possible to obtain a low-cost photovoltaic module, which can be particularly advantageous when the photovoltaic module is intended for use in a constellation of satellites, which can be very numerous.

[0093] In one embodiment, the photovoltaic module may be free of rare and expensive materials, such as cells made from so-called IILV materials. For example, it may be without a back face in the form of a sandwich combining an aluminum honeycomb and carbon composites.

[0094] The photovoltaic cells of a string can be arranged in a tile pattern. By 'arranged in a tile pattern', it is understood that the cells are connected to each other by means of edge-to-edge bonding, in particular by an electrical seal, for example an ECA (Electrically Conductive Adhesive). Such a tile-like configuration is called a 'string shingle' in English.

[0095] The invention advantageously allows the reinforcement of the photovoltaic module, even for a module comprising photovoltaic cells arranged in tiles.

[0096] The front face can be defined by a first transparent protective layer made of glass or one or more polymers, chosen from the following list, which is not exhaustive: polyurethane (PU), polypropylene (PP), epoxy, polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polyamide (PA), polyimide (PI), polyetheretherketone (PEEK), fluorinated polymer, including polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), ethylene tetrafluoroethylene (ETFE), ethylene chlorotrifluoroethylene (ECTFE), polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE) and / or fluorinated ethylene propylene (FEP).

[0097] The rear face can be defined by a second protective layer, transparent or not, made from one or more polymers, chosen from the preceding list.

[0098] The front face can be defined by a first transparent protective layer, the thickness of the first protective layer being between 5 pm and 500 pm, or even between 6 pm and 400 pm, or even between 7 pm and 300 pm, better between 8 pm and 200 pm, even better between 9 pm and 100 pm, or even between 10 pm and 80 pm, being in particular between 12 and 50 pm.

[0099] The rear face can be defined by a second protective layer, transparent or not, the thickness of the second protective layer being between 5 pm and 500 pm, or even between 6 pm and 400 pm, or even between 7 pm and 300 pm, better between 8 pm and 200 pm, even better between 9 pm and 100 pm, or even between 10 pm and 80 pm, being in particular between 12 and 50 pm.

[0100] In another embodiment, the rear face can be defined by a second protective layer, transparent or not, made of glass. The thickness of the second protective glass layer can be between 10 µm and 1000 µm, or even between 20 µm and 800 µm, or even between 30 µm and 600 µm, better between 40 µm and 400 µm, even better between 50 µm and 300 µm, or even between 60 µm and 200 µm, being notably on the order of 100 µm.

[0101] Alternatively, the front face defined by the first protective layer and / or the rear face defined by the second protective layer can be composed of an assembly of several materials chosen from: glass, polymer, hybrid compounds, this list not being exhaustive.

[0102] The surface mass of the photovoltaic module can be less than 3 kg / m2, or even less than 2 kg / m2, or even less than 1 kg / m2.

[0103] Solar photovoltaic generator and space object

[0104] The invention also relates, independently or in combination with the above, to a solar photovoltaic generator comprising one or more photovoltaic modules as described above.

[0105] The solar photovoltaic generator can be designed for a terrestrial application or, alternatively, for an extraterrestrial application, in particular space.

[0106] The invention thus relates to a solar photovoltaic generator for extraterrestrial application, particularly space-based, comprising one or more photovoltaic modules as described above.

[0107] The invention also relates, independently or in combination with the above, to a space object comprising a solar photovoltaic generator for extraterrestrial, in particular space, application, as described above.

[0108] The space object may be chosen from the following, non-exhaustive list: airplane, drone, airship, stratospheric aircraft, satellite, Earth satellite, low Earth orbit satellite, lunar base, Martian base. The space object may, in particular, be configured for use in a low Earth orbit, for example below 2000 km. Manufacturing method

[0109] The stiffener(s) according to the invention can be put in place during the manufacture of the photovoltaic module.

[0110] The invention thus relates, independently or in combination with the foregoing, to a method of manufacturing a photovoltaic module, in particular as defined above, a method in which a stack comprising a front face and a rear face is provided, between which is arranged an encapsulating assembly of photovoltaic cells, with a plurality of strings each of one or more photovoltaic cells, the photovoltaic cell(s) of a string being placed in series along a longitudinal axis of the string, a method in which, before lamination of the stack, a plurality of stiffeners are placed between the front face and the rear face, with at least one longitudinal stiffener placed between the strings of photovoltaic cells, so as to extend longitudinally between two strings of photovoltaic cells, before lamination of the stack.

[0111] The stack is then laminated, which ensures that all the layers of the stack remain together and that they are well cohesive.

[0112] The lamination step is configured to allow the stiffeners to bond together, in particular by heat sealing. Thus, the stiffeners acquire a continuity which strengthens the photovoltaic module.

[0113] Alternatively, the stiffeners can already be joined together before the lamination step, for example being cut together with each other.

[0114] The stiffener(s) may be arranged between the front face and the encapsulating assembly. If necessary, one or more stiffeners from among the plurality of stiffeners may be arranged between the encapsulating assembly and the rear face.

[0115] After lamination, the front face and / or the rear face can follow the reliefs created by the stiffeners present between the front face and the encapsulating assembly and / or between the encapsulating assembly and the rear face.

[0116] Furthermore, at least one transverse stiffener can be arranged transversely to the strings of photovoltaic cells. Brief description of the drawings

[0117] The invention will be better understood upon reading the detailed description that follows, the non-limiting examples of embodiments thereof, and upon examination of the accompanying drawing, in which:

[0118] [Fig. 1] The [Fig. 1] is a schematic and partial perspective view of a photovoltaic module.

[0119] [Fig.2] Fig.2 is a schematic and partial cross-sectional view of the module photovoltaic of the [Fig.l].

[0120] [Fig.3] Fig.3 is a schematic and partial cross-sectional view of a module photovoltaic according to the invention.

[0121] [Fig.4] Fig.4 is a schematic and partial cross-sectional view of the module photovoltaic of the [Fig.3] before lamination.

[0122] [Fig.5] [Fig.5] is a schematic and partial top view of the module photovoltaic of the [Fig.3].

[0123] [Fig.6] Fig.6 is a schematic and partial cross-sectional view of a variant of Production of a photovoltaic module prior to lamination.

[0124] [Fig.7] Fig.7 is a schematic and partial cross-sectional view of a variant of photovoltaic module manufacturing.

[0125] [Fig.8] Fig.8 is a schematic and partial top and detail view of the photovoltaic module of the [Fig.3].

[0126] [Fig.9] Fig.9 is a schematic and partial top and detail view of the photovoltaic module of the [Fig.3].

[0127] [Fig. 10] The [Fig. 10] is a schematic and partial cross-sectional view of the photovoltaic module of the [Fig.3].

[0128] [Fig. 11] The [Fig. 11] is a view analogous to the [Fig.8] of variant embodiments.

[0129] [Fig. 12] The [Fig. 12] is a view analogous to the [Fig.5] of an alternative embodiment.

[0130] [Fig. 13] The [Fig. 13] is a view analogous to the [Fig.5] of an alternative embodiment.

[0131] [Fig. 14] The [Fig. 14] is a view analogous to the [Fig.5] of an alternative embodiment.

[0132] [Fig. 15] The [Fig. 15] is a schematic and partial cross-sectional view of a stiffener.

[0133] [Fig. 16] The [Fig. 16] is a view analogous to the [Fig. 15] of variant embodiments of stiffener.

[0134] [Fig. 17] The [Fig. 17] is a view analogous to the [Fig. 15] of a variant embodiment of stiffener. Detailed description

[0135] Figures 1 and 2 illustrate a photovoltaic module M comprising several superimposed layers assembled together:

[0136] - A first protective layer 1 on the front face; this first layer of Protection 1 is usually made of glass, for example, clear tempered glass approximately 3 to 4 mm thick or glass with a thickness between 10 µm and 500 µm. Alternatively, it can be based on multi-layer polymers and be of a much lower thickness, for example between 12 and 50 µm;

[0137] - A second protective layer 3 commonly called "backsheet", opposite rear; this second layer 3 is usually made of multi-layer polymers or tempered glass like the first protective layer 1; it can be opaque or transparent, single-layer or multi-layer;

[0138] - An intermediate layer 2, intercalated between the first layer 1 and the second layer 3, allowing the assembly of one side of the first protective layer 1 and the other side of the second protective layer 3; this intermediate layer comprising photovoltaic cells 20, electrical connectors 22 and an encapsulating assembly 21 arranged around the photovoltaic cells.

[0139] In the following description, the front face of the photovoltaic module M corresponds to a face of the module receiving light rays, and the rear face corresponds to the face opposite the front face. The two protective layers 1 and 3 may have a stiffening function and / or a surface protection function.

[0140] The second layer 3 can, in particular, provide gas and water impermeability, electrical protection / insulation, and mechanical protection. This second layer 3 can be made of a fluoropolymer. This could be polyvinyl fluoride (PVF), for example, marketed under the name TEDLAR (registered trademark) by DuPont (registered trademark). Without limitation, the first layer 1 can itself be composed of a stack of several layers: a PVF layer, a PET (polyethylene terephthalate) layer, and another PVF layer.

[0141] In the intermediate layer 2, the encapsulating assembly 21 is conventionally made of a polymer material, for example a transparent elastomer, in which at least one electrically or optically active element, such as photovoltaic cells, is encapsulated or coated. This may be a polymer such as EVA (Ethylene-Vinyl Acetate) forming a material to which the elements can adhere the first layer 1 on one side and the second layer 3 on the other side and allow the assembly of the three layers together.

[0142] The three layers can be assembled together by hot rolling, so that the first layer and the second layer come to adhere to the material of the encapsulating assembly 21, thus forming a monobloc stack.

[0143] In the intermediate layer 2, the photovoltaic cells 20 comprise silicon, in particular multi- or monocrystalline silicon, and are connected to each other in series / parallel, forming several strings of cells. Electrical connection elements 22, for example made of copper, provide the electrical connections between the cells 20 in each string.

[0144] The photovoltaic cells of a string are arranged in tiles, being connected to each other by means of gluing the edges of cells, in particular by an electrical joint, for example an ECA glue.

[0145] In the example described with reference to Figures 3 to 5, the photovoltaic module comprises eight strings of cells 20, arranged in two rows of four strings. Of course, such a configuration is not limiting, and the photovoltaic module could have a different number of rows and a different number of strings per row. The photovoltaic cells in a string are placed in series along a longitudinal axis of the string X.

[0146] The stack further comprises according to the invention a plurality 10 of stiffeners arranged between the front face and the rear face, more precisely arranged between the front face and the encapsulating assembly, as illustrated in figures 3 and 4.

[0147] As schematically illustrated in [Fig. 4], the stiffeners according to the invention are installed during manufacturing, before the stack is laminated. The stack is then laminated, which ensures that all the layers of the stack remain stable and cohesive. The lamination step is configured to allow the stiffeners to bond together, notably by heat sealing. Thus, the stiffeners acquire a continuity that strengthens the photovoltaic module M.

[0148] After lamination, the front face and / or the rear face can follow the reliefs created by the stiffeners present between the front face and the encapsulating assembly and / or between the encapsulating assembly and the rear face, as illustrated in [Fig.3].

[0149] The plurality of stiffeners in this example comprises, as illustrated in [Fig.5], five longitudinal stiffeners 11 placed between the strings of photovoltaic cells 20, so as to extend longitudinally between two strings of photovoltaic cells 20, along the X axis.

[0150] The longitudinal stiffeners 11 are elongated in the shape of a beam, being very rigid in bending.

[0151] In an alternative embodiment illustrated in [Fig. 6], longitudinal stiffeners 11 of the plurality of stiffeners 10 are also arranged between the encapsulating assembly and the rear face. Thus, the module M of [Fig. 6] comprises, on the one hand, longitudinal stiffeners 11 arranged between the front face and the encapsulating assembly and, on the other hand, longitudinal stiffeners 11 arranged between the encapsulating assembly and the rear face, being arranged symmetrically with respect to a plane of symmetry passing through the encapsulating assembly. It should be noted that the longitudinal stiffeners 11 arranged between the encapsulating assembly and the rear face are superimposed with the longitudinal stiffeners 11 arranged between the front face and the encapsulating assembly.

[0152] In another embodiment illustrated in [Fig. 7], the photovoltaic module M lacks longitudinal stiffeners arranged between the encapsulating assembly and the rear face, but includes an additional reinforcing layer 30 made of composite materials arranged between the encapsulating assembly 2 and the rear face 3. A maximum gap e between the stiffeners 11 and the reinforcing layer 30 is approximately 10 mm. Alternatively, the photovoltaic module M could lack a second stiffening layer, comprising, for example, stiffeners between the encapsulating assembly and the rear face with also a reinforcing layer arranged between the encapsulating assembly 2 and the rear face.

[0153] As can be seen in [Fig.5], the plurality of stiffeners 10 comprises, on the one hand, longitudinal stiffeners arranged between two adjacent strings, and on the other hand, two longitudinal stiffeners arranged between one or more strings and an edge of the photovoltaic module M. Thus, a distance dl between a string and the adjacent stiffener, measured in the plane of the photovoltaic module, is for example on the order of 2 mm, as illustrated in [Fig.8].

[0154] Similarly, a distance d2 between the edge of the photovoltaic module and the edges of the end longitudinal stiffeners is, for example, on the order of 3 mm.

[0155] The width 11 of a stiffener can be about 20 mm.

[0156] The width is advantageously large enough to allow the stiffeners to provide rigidity to the photovoltaic module, without, however, reducing the photovoltaic module's surface area too much. The area occupied by the stiffeners need not exceed 40% of the photovoltaic module's surface area.

[0157] Furthermore, the stiffener(s), longitudinal or transverse, may or may not extend beyond the encapsulating assembly.

[0158] By way of example, [Fig.9] has illustrated a stiffener 11 protruding from the encapsulating assembly by a length 12 for example of about 50 mm.

[0159] The extension of the stiffeners can facilitate the attachment of the photovoltaic module to a mounting structure 40, as illustrated in [Fig. 10].

[0160] The width of a stiffener can vary in the portion that extends beyond the protective layers; in particular, the width can increase. The width of the stiffener outside the protective layers is then defined as 13. This width 13 can be approximately 5 cm. The width can be increased through various geometries, specifically with a right angle, a bevel, or a fillet, as illustrated in [Fig. 11].

[0161] Alternatively, there may be no overhang, as illustrated in [Fig. 12]. In this case, the stiffeners are flush with the encapsulating assembly.

[0162] Furthermore, as seen in [Fig. 5] already described, the photovoltaic module M includes a transverse stiffener 12. Alternatively, it may include several, as seen in [Fig. 13], in which the photovoltaic module M includes three transverse stiffeners 12 arranged transversely to the strings of photovoltaic cells, which extend perpendicularly to the longitudinal stiffeners 11. In the case where the number of rows of strings of photovoltaic cells is greater than 2, the number of transverse stiffeners may be greater than 3.

[0163] The transverse stiffener(s) may or may not protrude from the enclosing assembly, as illustrated respectively in Figures 13 and 14.

[0164] In addition, the plurality of stiffeners 10 comprises on the one hand a transverse stiffener 12 arranged between adjacent garlands, and on the other hand two transverse stiffeners 12 arranged between garlands and an edge of the photovoltaic module M, as illustrated in Figures 13 and 14.

[0165] In an example of an embodiment illustrated in [Fig.15], a stiffener 11, 12 comprises a core 15 made of a lightweight material, the core being covered with an advantageously resistant coating 16, in particular in a composite material.

[0166] The thickness hl of the coating can be approximately 100 µm. The thickness h2 of the core can be approximately 10 or 20 mm. The thickness hl + 2*h2 of the stiffener can be between 2 and 20 mm.

[0167] The core 16 can be in cross-section of a general shape chosen from the following list, which is not limiting: circular, polygonal, rectangular, as illustrated in [Fig. 15], triangular or semi-circular, as illustrated in [Fig. 16].

[0168] A stiffener 11,12 can have a cross-section of general circular, polygonal, in particular rectangular shape as illustrated in [Fig. 15], triangular or semi-circular shape, as illustrated in [Fig. 16].

[0169] In the embodiments of [Fig. 16], the stiffeners retain their sandwich structure with coatings 16 made of composite materials, but the web 15 no longer has a rectangular or rectangular shape, but can take more atypical shapes, respectively in a half-cone or semi-circular shape on the one hand, and on the other hand in a triangular or pyramid shape.

[0170] Such cores can be shaped by 3D printing with filaments possibly enriched with fiber, such as filaments of nylon reinforced with carbon fibers, of PA12 reinforced with carbon fibers, of polyethylene terephthalate reinforced with carbon fibers, of polycarbonate reinforced with carbon fibers, or of PEKK-A reinforced with carbon fibers.

[0171] In the structures illustrated in [Fig. 16], the stiffener has a flat base with a rectangular cross-section and a thickness hl between 50 pm and 2 mm. The remainder of the sandwich structure, with a height h4 between 0.5 mm and 50 mm, ideally 20 mm, has a core with a semi-oval or triangular cross-section and a top covering over this core. The top covering and the core have the same characteristics as the stiffener in [Fig. 15].

[0172] A tapering shape can facilitate the insertion of the stiffener and its integration into the photovoltaic module. Indeed, such a shape allows the front or rear face to completely surround the stiffener, thus smoothing the transition between the areas with and without stiffeners and improving stress distribution.

[0173] The stiffener structure can be symmetrical, with symmetry about its vertical and horizontal median planes.

[0174] In another embodiment illustrated in [Fig. 17], the stiffener(s) are single-layer, comprising only one layer of composite material, the fibers and matrix of which may be derived from the same material families as the composite material of the coated core stiffeners, as described above. This single layer may have a thickness h3 of approximately 500 µm.

Claims

Demands

1. Photovoltaic module (M) comprising a front face (1) and a rear face (3) between which is arranged an assembly encapsulating (2) photovoltaic cells (20), the module (M) comprising a plurality of strings each of one or more photovoltaic cells (20), the photovoltaic cell(s) (20) of a string being placed in series along a longitudinal axis of the string, the module (M) further comprising a plurality (10) of stiffeners (11, 12) arranged between the front face (1) and the rear face (3), the plurality (10) of stiffeners comprising at least one longitudinal stiffener (11) placed between the strings of photovoltaic cells (20), so as to extend longitudinally between two strings of photovoltaic cells (20).

2. Photovoltaic module according to the preceding claim, one or more stiffeners (11, 12) from the plurality (10) of stiffeners being arranged between the front face (1) and the encapsulating assembly (2), in particular one or more longitudinal stiffeners from the plurality of stiffeners being arranged between the front face and the encapsulating assembly.

3. Photovoltaic module according to any one of the preceding claims, one or more stiffeners (11, 12) from the plurality (10) of stiffeners being arranged between the encapsulating assembly (2) and the rear face (3), in particular one or more longitudinal stiffeners from the plurality of stiffeners being arranged between the encapsulating assembly and the rear face.

4. Photovoltaic module according to claim 2 and claim 3, one or more stiffeners, in particular longitudinal, among the stiffener(s), in particular longitudinal, arranged between the encapsulating assembly (2) and the rear face (3) being superimposed with the stiffener(s) arranged between the front face (1) and the encapsulating assembly (2).

5. Photovoltaic module according to any one of claims 1 or 2, comprising a reinforcing layer (30), in particular of composite material, disposed between the encapsulating assembly (2) and the rear face (3).

6. Photovoltaic module according to any one of the preceding claims, comprising one or more longitudinal (11) and / or transverse (12) stiffeners arranged between one or more strings and an edge of the photovoltaic module.

7. Photovoltaic module according to any one of the preceding claims, comprising one or more transverse stiffeners (12) arranged transversely to the strings of photovoltaic cells (20).

8. Photovoltaic module according to any one of the preceding claims, a stiffener (11, 12) comprising a core (15), in particular a core made of a lightweight material, the core being in particular covered in whole or in part with a coating (16), in particular a coating of a composite material.

9. Photovoltaic module according to any one of the preceding claims, the photovoltaic cells (20) comprising silicon, in particular multi- or monocrystalline silicon.

10. Photovoltaic module according to any one of the preceding claims, the photovoltaic cells (20) of a string being arranged in tiles.

11. Photovoltaic module according to any one of the preceding claims, the front face (1) being defined by a first transparent protective layer made of glass or of one or more polymers, selected from the following list: polyurethane (PU), polypropylene (PP), epoxy, polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polyamide (PA), polyimide (PI), polyetheretherketone (PEEK), fluorinated polymer, in particular polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), ethylene tetrafluoroethylene (ETFE), ethylene chlorotrifluoroethylene (ECTFE), polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE) and / or fluorinated ethylene propylene (FEP).

12. Photovoltaic module according to any one of the preceding claims, the front face (1) being defined by a first transparent protective layer, the thickness of the first protective layer being between 5 µm and 500 µm, or even between 6 µm and 400 µm, or even between 7 µm and 300 µm, better between 8 µm and 200 µm, still better between 9 µm and 100 pm, or even between 10 pm and 80 pm, being notably between 12 and 50 pm.

13. Photovoltaic module according to any one of the preceding claims, the surface mass of the photovoltaic module (M) being less than 3 kg / m2, or even less than 2 kg / m2, or even less than 1 kg / m2.

14. Solar photovoltaic generator for extraterrestrial application, in particular space, comprising one or more photovoltaic modules (M) according to any one of the preceding claims.

15. Space object comprising a solar photovoltaic generator for extraterrestrial application, in particular space, according to the preceding claim.

16. A method for manufacturing a photovoltaic module, in particular according to any one of claims 1 to 13, wherein a stack is provided having a front face and a rear face between which is arranged an encapsulating assembly of photovoltaic cells, with a plurality of strings each of one or more photovoltaic cells, the photovoltaic cell(s) of a string being placed in series along a longitudinal axis of the string, a method wherein, prior to lamination of the stack, a plurality of stiffeners are placed between the front face and the rear face, with at least one longitudinal stiffener placed between the strings of photovoltaic cells, so as to extend longitudinally between two strings of photovoltaic cells, prior to lamination of the stack.

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