Assembly including a photovoltaic module applied to a circulable zone

Abstract

The main subject of the invention is a photovoltaic module (1) applied to the circulable zone (2). The photovoltaic module (1) is characterised in that the first layer (3) consists of at least one transparent polymer and includes a plurality of sheets (8) that are independent from one another, each sheet (8) being located facing at least one photovoltaic cell (5), so as to form a discontinuous front side of the photovoltaic module (1), and in that the rigidity of the encapsulating assembly (6a, 6b) is defined by a young's modulus (e) of the encapsulating material higher than or equal to 75 mpa at room temperature and a thickness (e) of the encapsulating assembly (6a, 6b) comprised between 0.4 and 1 mm.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of photovoltaic modules, comprising a set of photovoltaic cells electrically connected to each other, and in particular so-called "crystalline" photovoltaic cells, that is to say, those based on silicon crystals or silicon polycrystals.

[0002] The invention can be implemented in numerous applications, being particularly relevant to those requiring the use of lightweight, flexible, and robust photovoltaic modules resistant to shocks and high mechanical loads. It is thus ideally suited for integration into areas accessible to pedestrians and / or vehicles, such as roads, cycle paths, industrial platforms, squares, and sidewalks, among others. Such an application is commonly referred to as a "solar road."

[0003] The invention thus proposes a photovoltaic structure assembly comprising a photovoltaic module applied to a circulable area, the use of such a photovoltaic module for its application to a circulable area, as well as a method for making such a photovoltaic structure assembly. PREVIOUS STATE OF THE ART

[0004] A photovoltaic module is an assembly of photovoltaic cells arranged side by side between a first transparent layer forming a front face of the photovoltaic module and a second layer forming a back face of the photovoltaic module.

[0005] The first layer, forming the front face of the photovoltaic module, is advantageously transparent to allow the photovoltaic cells to receive light. It is traditionally made of a single sheet of glass, approximately 3 mm thick. The second layer, forming the back face of the photovoltaic module, can be made of glass, metal, or plastic, among other materials. It is usually composed of a polymeric structure based on an electrically insulating polymer, such as polyethylene terephthalate (PET) or polyamide (PA), which may be protected by one or more layers of fluoropolymers, such as polyvinyl fluoride (PVF) or polyvinylidene fluoride (PVDF), and has a thickness of approximately 300 µm.

[0006] Photovoltaic cells can be electrically connected in series with each other by front and rear electrical contact elements, called connecting conductors, and formed for example by copper strips, respectively arranged against the front faces (faces facing the front face of the photovoltaic module intended to receive a light flux) and rear faces (faces facing the rear face of the photovoltaic module) of each of the photovoltaic cells.

[0007] Furthermore, the photovoltaic cells, located between the first and second layers forming the front and back faces of the photovoltaic module respectively, are encapsulated. Typically, the encapsulant chosen is an elastomer (or rubber) type polymer, and may, for example, consist of two layers (or films) of poly(ethylene-vinyl acetate) (EVA) between which the photovoltaic cells and the cell connecting conductors are arranged. Each EVA layer can have a thickness of at least 0.3 mm and a Young's modulus of 30 MPa or less at room temperature.

[0008] Typically, the photovoltaic module manufacturing process involves a single step of laminating the various layers described above, at a temperature of 140°C or higher, or even 150°C, for a period of at least 8 minutes, or even 15 minutes. After this lamination operation, the two EVA layers melt to form a single layer in which the photovoltaic cells are embedded.

[0009] Nevertheless, these known prior art designs of a photovoltaic module are not entirely satisfactory and present several drawbacks for at least some of their applications.

[0010] In the context of the application of the solar road type, a need has arisen to use roads or pavements as means of energy production during the day, whether to power nearby buildings (businesses, eco-districts, solar farms, individual houses, among others) or to power the electrical grid or traffic assistance devices, for example.

[0011] Firstly, the presence of a glass plate to form the front face of the photovoltaic module is incompatible with certain photovoltaic module applications that may require a relatively lightweight module and ease of shaping. Conversely, prior art designs using glass on the front face of photovoltaic modules result in a high module weight and limited integration capabilities.

[0012] For applications such as solar roads, photovoltaic modules with a glass front face are, firstly, not flexible enough to accommodate road deformation, which is on the order of 1 mm per 100 mm along both horizontal axes, depending on the road's width and length. Secondly, these photovoltaic modules are not sufficiently resistant to static load if glued directly to the road surface. In other words, the road surface's roughness can cause the photovoltaic cells to be punctured by the back face of the module, leading to a risk of cell breakage.

[0013] Solutions have been considered to replace the glass front face of photovoltaic modules with plastic materials, while maintaining the classic architecture and manufacturing method of photovoltaic modules. As examples, French patent application FR 2 955 051 A1 and international applications WO 2012 / 140585 A1 and WO 2011 / 028513 A2 describe possible alternatives to glass for designing the front face of photovoltaic modules, including the use of polymer sheets, with a thickness less than or equal to 500 µm, such as polyvinylidene fluoride (PVDF), ethylene tetrafluoroethylene (ETFE), polymethyl methacrylate (PMMA) or polycarbonate (PC).

[0014] However, simply substituting glass with a polymer material to obtain a lightweight and flexible photovoltaic module generally results in increased vulnerability of the module to shocks and mechanical loads, which is unacceptable for certain applications.

[0015] Furthermore, in these examples of prior art implementation, the front face (without glass) of each photovoltaic module is continuous, meaning it forms a single sheet or plate covering the entire module. This can limit, and often result in insufficient, flexibility for each individual photovoltaic module. Moreover, this design also exacerbates differential expansion stresses between the different layers of the structure, potentially leading to undesirable deformations or delamination at the structure's interfaces, such as the interface between the encapsulating material and the external layers.

[0016] Several solutions have been proposed to achieve a degree of discontinuity on the front face of a photovoltaic module in order to improve module flexibility and better manage differential expansion constraints. For example, US patent application 2014 / 0000683 A1 describes a method for encapsulating individual photovoltaic cells. The encapsulated cells can then be interconnected to create a flexible photovoltaic module. Furthermore, US patent application 2014 / 0030841 A1 describes the implementation of a photovoltaic module on a flexible substrate. The photovoltaic module is composed of "sub-modules" made up of interconnected photovoltaic cells, each sub-module being electrically independent of its neighbors. Finally, JP patent application 2013 / 038228 A discloses a flexible photovoltaic module on a walkable surface.However, the solutions described above do not prove to be entirely satisfactory in terms of flexibility, resistance to shocks and mechanical loads, performance and cost of photovoltaic modules, particularly for demanding applications which put a lot of stress on their mechanical resistance. DESCRIPTION OF THE INVENTION

[0017] There is therefore a need to propose an alternative design solution for an assembly equipped with a photovoltaic module applied to a vehicular area, in order to meet at least some of the constraints inherent to the applications targeted by the use of the photovoltaic module, in particular to improve the flexibility, rigidity, lightness, and resistance to shocks and mechanical loads of the photovoltaic module. Specifically, there is a need to further refine photovoltaic modules intended for integration into vehicular areas, for pedestrians and / or vehicles, for example, to increase their resistance to the load induced by the passage of a vehicle while maintaining a degree of flexibility.

[0018] The invention aims to remedy at least partially the needs mentioned above and the drawbacks related to prior art achievements.

[0019] The invention thus relates, according to one of its aspects, to a photovoltaic structure assembly, comprising: a walkable area, a photovoltaic module applied to the walkable area, the photovoltaic module comprising at least: a first transparent layer forming the front face of the photovoltaic module intended to receive a light flux, an assembly of a plurality of photovoltaic cells arranged side by side and electrically connected to each other, an assembly encapsulating the plurality of photovoltaic cells, a second layer forming the rear face of the photovoltaic module, intended in particular to be attached to a walkable area, the encapsulating assembly and the assembly of a plurality of photovoltaic cells being located between the first and second layers, and a fixing layer, consisting in particular of a bituminous adhesive or of one or more acrylic resins, located between the walkable area and the photovoltaic module, enabling the adhesion of the photovoltaic module to the walkable area,characterized in that the first layer is made of at least one transparent polymer material and comprises a plurality of plates independent of each other, each plate being located opposite at least one photovoltaic cell, so as to form a discontinuous front face of the photovoltaic module, , and in that the rigidity of the encapsulating assembly is defined by a Young's modulus of the encapsulating material greater than or equal to 75 MPa at room temperature and a layer thickness between 0.4 and 1 mm.

[0020] Initially, that is, before any lamination process, the encapsulating assembly consists of two layers of encapsulating material, called core layers, between which a plurality of photovoltaic cells are encapsulated. However, after the lamination process, the layers of encapsulating material melt to form a single layer (or assembly) in which the photovoltaic cells are embedded. Before any lamination process, each layer of encapsulating material can thus have a stiffness defined by a Young's modulus of the encapsulating material greater than or equal to 75 MPa at room temperature and a layer thickness of between 0.2 and 1 mm, or even between 0.2 and 0.5 mm.

[0021] The assembly encapsulating the plurality of photovoltaic cells is thus constituted by the two layers of encapsulation material, namely the layers of encapsulation material which before lamination are in direct contact with the photovoltaic cells.

[0022] The term "transparent" means that the material of the first layer forming the front face of the photovoltaic module is at least partially transparent to visible light, allowing at least about 80% of this light to pass through.

[0023] Furthermore, the expression "independent plates" means that the plates are located at a distance from each other, each forming a unitary element independent of the first layer and of each other, superimposed on at least one photovoltaic cell. The combination of all these plates then forms the first layer with a discontinuous appearance.

[0024] Furthermore, the term "encapsulating" or "encapsulated" should be understood to mean that a collection of a plurality of photovoltaic cells is arranged in a volume, for example hermetically sealed, at least partly formed by layers of encapsulating material, joined together after lamination.

[0025] Furthermore, the expression "circulable area" refers to any area intended for the circulation of pedestrians and / or vehicles, such as, for example, a roadway (or highway), a motorway, a cycle path, an industrial platform, a square, a sidewalk, this list being by no means exhaustive.

[0026] Furthermore, the expression "room temperature" refers to a temperature between approximately 15 and 30°C.

[0027] Thanks to this invention, it may be possible to provide an alternative solution for designing a photovoltaic assembly comprising a flexible photovoltaic module that is also sufficiently robust to withstand shocks and mechanical loads, particularly after application in a walkable area. Specifically, the use of a discontinuous front face can give the photovoltaic module a flexible character, facilitating its application to non-planar, such as curved, surfaces. Furthermore, the use of a high-rigidity encapsulating material on both sides of the photovoltaic cells can adequately protect them against the risk of high mechanical loads or shocks by limiting their flexing and thus reducing the risk of breakage.Furthermore, the absence of a glass front panel allows the photovoltaic module to be lighter than a prior art module, typically on the order of 12 kg / m², depending on the thickness of the various layers used. Finally, the use of a discontinuous front panel made of a polymer material can mitigate thermal expansion problems during outdoor use. Since thermal expansion is proportional to the dimensions of the first layer forming the front panel, using plates with dimensions close to those of the photovoltaic cells can significantly limit movement caused by thermal stresses that could lead to delamination or uncontrolled deformation of the photovoltaic module.

[0028] The photovoltaic structure assembly according to the invention may further comprise one or more of the following characteristics taken individually or in any possible technical combinations.

[0029] The second layer forming the back face of the photovoltaic module can also be discontinuous. In other words, the second layer can also consist of multiple independent plates, each plate positioned opposite, or overlapping, at least one photovoltaic cell. The presence of a discontinuous back face on the photovoltaic module can, for example, further improve the module's flexibility, facilitating its application on trafficable areas with surface roughness.

[0030] Moreover, even if the first layer forming the front face of the photovoltaic module, and possibly the second layer forming the rear face of the module, have a discontinuous appearance, the whole of a plurality of photovoltaic cells and the encapsulating whole are advantageously continuous.

[0031] According to a particular embodiment of the invention, each plate of the first layer, and optionally of the second layer, can be positioned opposite several photovoltaic cells. This can notably be the case for photovoltaic cells with dimensions smaller than those of conventional photovoltaic cells, typically 156 x 156 mm.

[0032] Furthermore, when a single photovoltaic cell is located opposite each plate of the first layer, and possibly of the second layer, each plate can have dimensions at least equal to those of the photovoltaic cell on which it is superimposed.

[0033] The photovoltaic module is advantageously devoid of a first layer forming the front face of the module, which is made of glass. Thus, as mentioned previously, it is possible to improve the lightness and integration capabilities of the photovoltaic module.

[0034] The encapsulation material forming the two core encapsulation material layers of the encapsulating assembly may have a Young's modulus at room temperature greater than or equal to 100 MPa, in particular greater than or equal to 150 MPa, or even 200 MPa. It is notably 220 MPa.

[0035] The encapsulating assembly can be formed from two layers of encapsulating material having the same or different thicknesses.

[0036] The second layer forming the back face of the photovoltaic module can preferably be made of at least one composite material, in particular of the polymer / fiberglass type.

[0037] The second layer also preferably has a coefficient of thermal expansion less than or equal to 20 ppm, and preferably less than or equal to 10 ppm.

[0038] The second layer forming the back face of the photovoltaic module may or may not be transparent.

[0039] The stiffness of the second layer forming the back face of the photovoltaic module can be defined by a stiffness factor, corresponding to the Young's modulus at room temperature of the material of the second layer multiplied by the thickness of the second layer, between 5 and 15 GPa.mm.

[0040] Furthermore, the stiffness of the second layer forming the back face of the photovoltaic module can be defined by a Young's modulus at room temperature of the material of the second layer greater than or equal to 1 GPa, better greater than or equal to 3 GPa, even better greater than or equal to 10 GPa, and a thickness of the second layer between 0.2 and 3 mm.

[0041] In this way, the second layer forming the back face of the photovoltaic module can exhibit high rigidity, thus potentially limiting its flexibility. However, this high rigidity can reduce, or even prevent, the puncture of photovoltaic cells by the back face of the module—that is, the appearance of cracks and / or breaks in the photovoltaic cells—when the module is applied to a substrate with significant surface roughness.

[0042] The spacing between two neighboring, consecutive or adjacent photovoltaic cells may be greater than or equal to 1 mm, in particular between 1 and 30 mm, and preferably greater than or equal to 3 mm, in particular between 10 and 20 mm.

[0043] The two neighboring photovoltaic cells considered can be two neighboring cells of the same series (also referred to as a "string" in English) or two neighboring cells belonging respectively to two consecutive series of the set of photovoltaic cells.

[0044] The presence of significant spacing between photovoltaic cells allows for a similarly significant spacing between the plates of the first layer forming the front face of the photovoltaic module. This accentuates the discontinuous appearance of the module's front face, thus providing the module with flexibility to facilitate its application in walkable areas.

[0045] Advantageously, the spacing between two adjacent plates of the first layer, and possibly of the second layer, is less than or equal to the spacing between two adjacent photovoltaic cells.

[0046] The module may also preferentially include an intermediate layer called "damping" located between the first layer forming the front face of the photovoltaic module and the assembly encapsulating the plurality of photovoltaic cells, allowing the assembly, in particular by gluing, of the first layer onto the encapsulating assembly.

[0047] The intermediate layer may consist of at least one polymer material, in particular a thermoplastic or thermosetting polymer resin.

[0048] The intermediate layer can be in the form of a sheet or a liquid. It can be adhesive, such as PSA, or non-adhesive. It can be applied hot or at room temperature.

[0049] The stiffness of the intermediate layer can be defined by a Young's modulus of the intermediate layer material less than or equal to 50 MPa at room temperature and an intermediate layer thickness between 0.01 and 1 mm.

[0050] The intermediate layer can fulfill two main functions. Firstly, it can allow the first layer, forming the front face of the photovoltaic module, to adhere to the encapsulating assembly in cases where the two layers are not chemically compatible. Secondly, it can create a "damping" layer within the photovoltaic module, providing a degree of flexibility to improve the module's resistance to shocks and mechanical loads.

[0051] This intermediate layer may be optional, particularly absent when there is chemical compatibility between the first layer forming the front face of the photovoltaic module and the encapsulating assembly.

[0052] The photovoltaic module may also include an adhesive layer located between the second layer forming the back face of the photovoltaic module and the assembly encapsulating the plurality of photovoltaic cells, allowing the assembly, in particular by gluing, of the second layer onto the encapsulating assembly.

[0053] The term "adhesive layer" refers to a layer that, once the photovoltaic module is manufactured, allows the second layer to adhere to the encapsulating assembly. It is therefore a layer that ensures chemical compatibility and adhesion between the encapsulating material and the back surface.

[0054] Furthermore, the thickness of the first layer forming the front face of the photovoltaic module can be greater than or equal to 0.1 mm, in particular between 0.5 and 6 mm.

[0055] The walkable area may have a surface roughness.

[0056] Furthermore, as previously mentioned, the assembly includes a bonding layer, typically applied by adhesive, located between the walkable area and the photovoltaic module. The use of this bonding layer can provide a reinforced back face of the photovoltaic module, preventing the risk of punctures to the photovoltaic cells when the walkable area has a high surface roughness and the photovoltaic module is subjected to impact or high mechanical load. The interface between the back face of the module and the walkable area can thus be filled with a protective binder.

[0057] The fixing layer may contain an adhesive, for example an epoxy or polyurethane adhesive, among others. In particular, it may contain a special industrial adhesive.

[0058] The fixing layer may also include a bituminous binder, possibly reinforced by the addition of a polymer such as Styrene-Butadiene-Styrene (SBS), either hot or in emulsion.

[0059] According to one implementation, the fixing layer is spread directly onto the surface of the walkable area, in a thin layer, and then the photovoltaic module is placed on it while the glue has not hardened or the bituminous binder is still viscous and sticky.

[0060] In addition, the assembly may include a coating layer, allowing in particular the passage of pedestrians and / or vehicles, applied on the first layer forming the front face of the photovoltaic module, the coating layer being non-opaque and having a textured and irregular outer surface, in particular an irregularly macrotextured and microtextured outer surface, with an average PMT texture depth measured according to standard NF EN 13036-1 between 0.2 mm and 3 mm and a PSV value (for "Polished Stone Value" in English) according to standard NF EN 13043 of at least PSV 44, better PSV 50, even better PSV 53.

[0061] The coating layer can advantageously present an exterior surface reproducing the texture of a road surface coating suitable for traffic.

[0062] The term "irregularly" means that the surface features that give the coating layer its macrotexture and microtexture are not all the same shape or size. These features can be obtained from texturizing elements that are not uniform in shape or size, being uncalibrated.

[0063] The coating layer advantageously exhibits a transparency rate greater than 50%, for example between 50 and 95%, in a range of 100 nm around the peak efficiency of photovoltaic cells, particularly in the 500-700 nm range.

[0064] The average PMT texture depth of the coating layer can be at least 0.30 mm, better at least 0.6 mm.

[0065] In addition, the coating layer may include a non-opaque matrix, preferably with a Young's modulus at room temperature between 0.1 and 10 GPa. The matrix can be chosen from synthetic or plant-based materials, bituminous binders, preferably of penetration class according to standard EN 1426 160 / 220, 100 / 150, 70 / 100, 50 / 70, 40 / 60, 35 / 50, 30 / 45 or 20 / 30 (in tenths of mm), clear synthetic or plant-based road binders, preferably of penetration class according to standard EN 1426 160 / 220, 100 / 150, 70 / 100, 50 / 70, 40 / 60, 35 / 50, 30 / 45 or 20 / 30 (in tenths of mm) and polymeric binders.

[0066] The texture of the outer surface of the coating layer can be defined, at least partially, by non-opaque texturing elements, preferably irregularly shaped, or even better, randomly distributed. These texturing elements can be arranged in a single layer, preferably embedded approximately halfway into the coating matrix. They can be selected from aggregates of transparent or translucent, organic or mineral materials, including polycarbonate or glass. Their size can range from 0.1 mm to 10 mm, preferably from 0.4 to 4 mm, and even better from 0.9 to 1.4 mm.

[0067] The coating layer can, for example, be a bituminous type binder as defined in the NF EN 12591 standard, such as the Bituclair binder marketed by the company Colas.

[0068] The coating layer can still be a clear synthetic or plant-based road binder, such as the Végécol or Végéclair binders marketed by the company Colas.

[0069] The coating layer can also be a binder of purely synthetic or plant origin, the binder being preferably of organic nature, preferably of polymeric nature, such as an acrylic, epoxy or polyurethane resin, like the epoxy varnishes known as Vernis D marketed by the company Résipoly, or a Sovermol polyurethane marketed by the company BASF.

[0070] Preferably, photovoltaic cells are so-called "crystalline" cells, that is, based on silicon crystals or silicon polycrystals.

[0071] Furthermore, according to another aspect of the invention, the use, for its application on a trafficable area, in particular a roadway, of a photovoltaic module comprising at least: a first transparent layer forming the front face of the photovoltaic module intended to receive a light flux, an assembly of a plurality of photovoltaic cells arranged side by side and electrically connected to each other, an assembly encapsulating the plurality of photovoltaic cells, a second layer forming the rear face of the photovoltaic module, the encapsulating assembly and the assembly of a plurality of photovoltaic cells being located between the first and second layers, the first layer being made of at least one transparent polymer material and comprising a plurality of plates independent of each other, each plate being located opposite at least one photovoltaic cell, so as to form a discontinuous front face of the photovoltaic module, and the rigidity of the encapsulating assembly being defined by a Young's modulus of the encapsulating material greater than or equal to 75 MPa at room temperature and a thickness of the encapsulating assembly between 0.4 and 1 mm, the photovoltaic module being applied to the walkable area by means of a fixing layer, consisting in particular of a bituminous glue or of one or more acrylic resins.

[0072] Furthermore, according to another aspect of the invention, the method for constructing a photovoltaic structure assembly as defined above, comprising at least the following four successive steps: a) hot rolling at a temperature above 150°C of all the constituent layers of the photovoltaic module except the first layer forming the front face of the photovoltaic module and any intermediate layer known as the "damping" layer, located between the first layer and the assembly encapsulating the plurality of photovoltaic cells; b) rolling at a temperature less than or equal to 150°C, preferably 125°C, for example at ambient temperature, of the first layer forming the front face of the photovoltaic module, and of any intermediate layer, onto the constituent layers of the photovoltaic module rolled together during the first step a); c) application of a coating layer on the first layer forming the front face of the photovoltaic module, in particular to allow the passage of pedestrians and / or vehicles, the coating layer being non-opaque and having a textured and irregular outer surface.including an irregularly macrotextured and microtextured outer surface, with an average PMT texture depth measured according to standard NF EN 13036-1 between 0.2 mm and 3 mm and a PSV (for "Polished Stone Value") value according to standard NF EN 13043 of at least PSV 44, preferably PSV 50, and even better PSV 53; d) fixing the photovoltaic module to a walkable area to form the entire photovoltaic structure, by means of a fixing layer for the entire photovoltaic structure, consisting in particular of a bituminous adhesive or of one or more acrylic resins.

[0073] During the first step a) of lamination, the constituent layers of the photovoltaic module concerned are thus the set of a plurality of photovoltaic cells, the encapsulating set and the second layer forming the back face of the photovoltaic module.

[0074] Furthermore, before the implementation of the second step b), the plates of the first layer can advantageously be treated using Corona treatment equipment in order to obtain a surface energy greater than or equal to 48 dyn / cm.

[0075] The optional intermediate layer, sometimes called a "damping" layer, can facilitate the bonding of the first layer forming the front face of the module to the other layers. This intermediate layer is optional. In particular, it may not be necessary when there is chemical compatibility between the first layer forming the front face of the module and the encapsulating assembly.

[0076] As previously mentioned, the thickness of the encapsulating assembly can range from 0.4 to 1 mm, resulting from the lamination of at least two layers of encapsulating material, each with a thickness between 0.2 and 0.5 mm. These two layers of encapsulating material may also have different thicknesses.

[0077] Advantageously, the implementation of at least two rolling steps in the process according to the invention for the production of the photovoltaic module can make it possible to overcome possible problems of thermal expansion which may arise from the use of a front face of the module made of a polymer material.

[0078] Indeed, some layers of the photovoltaic module need to be laminated at a temperature of 140°C or higher, or even 150°C, but laminating at this temperature level in a single step, in accordance with prior art practice, of all the layers of the module, including the one forming the front face of the module, can give rise to uncontrolled conformation and significant delamination of the front face of the photovoltaic module due to excessive mechanical stresses.

[0079] Also, the presence of at least a second rolling stage at a lower temperature than for the first stage, for the rolling of the front face of the photovoltaic module, possibly combined with the presence of an intermediate layer called "damping" allowing the front face of the module to be glued to the encapsulation material and the damping of thermal stresses, can limit, or even prevent, thermal expansion.

[0080] Alternatively, according to another aspect of the invention, the invention also relates to a method for constructing a photovoltaic structure assembly as defined above, comprising at least the following three successive steps: a) hot rolling at a temperature of 150°C or higher of all the constituent layers of the photovoltaic module, b) application of a coating layer on the first layer forming the front face of the photovoltaic module, in particular to allow the passage of pedestrians and / or vehicles, the coating layer being non-opaque and having a textured and irregular outer surface, in particular an irregularly macro-textured and micro-textured outer surface, with an average texture depth (PMT) measured according to standard NF EN 13036-1 of between 0.2 mm and 3 mm and a PSV (for "Polished Stone Value") value according to standard NF EN 13043 of at least PSV 44, preferably PSV 50, even better PSV 53, c) fixing the photovoltaic module on a walkable area to form the photovoltaic structure assembly, by means of a fixing layer for the photovoltaic structure assembly,consisting in particular of a bituminous adhesive or of one or more acrylic resins.

[0081] The photovoltaic structure assembly and the method according to the invention may include any of the previously stated characteristics, taken in isolation or in any technically possible combinations with other characteristics. BRIEF DESCRIPTION OF THE DRAWING

[0082] The invention will be better understood by reading the detailed description that follows, of a non-limiting example of its implementation, as well as by examining the single, schematic and partial figure of the attached drawing, illustrating, in section and exploded view, an example of the realization of a photovoltaic structure assembly according to the invention.

[0083] In this unique figure, the different parts represented are not necessarily shown on a uniform scale, to make the figure more legible. DETAILED DESCRIPTION OF A PARTICULAR METHOD OF IMPLEMENTATION

[0084] Reference is made below to the figure 1 illustrating in cross-section and exploded view an example of the realization of a photovoltaic structure assembly 10 according to the invention.

[0085] It should be noted that the figure 1This corresponds to an exploded view of the photovoltaic structure assembly 10 before the lamination steps of the process according to the invention. Once the lamination steps are completed, the different layers are actually superimposed on one another, but also slightly deformed so that at least the plates 8 of the first layer 3 are embedded in the assembly formed by the intermediate layer 9 and the encapsulating assembly 6a, 6b, which are deformed. The lamination steps ensure hot and vacuum pressing. Depending on the thicknesses of the different layers, the plates 8 may or may not be flush with the photovoltaic module 1, as the material of the intermediate layer 9 and perhaps that of the encapsulating assembly 6a, 6b may also fill at least part of the spaces between the plates 8.

[0086] As explained previously, the photovoltaic module 1 according to the invention is designed to be sufficiently flexible to allow its application, particularly by bonding, to a trafficable area 2, especially a road surface, which may have a rough surface, in other words, not necessarily flat and smooth. Furthermore, the photovoltaic module 1 according to the invention is also designed to withstand static or dynamic pressures of up to 1500 kN / m², or even 5000 kN / m². Advantageously, the trafficable area 2 is sufficiently rigid so as not to deform when the same stress is applied as that applied to the photovoltaic module 1.

[0087] As can be seen on the figure 1, the photovoltaic module 1 comprises a first transparent layer 3 forming the front face of the module 1 intended to receive a light flux, an encapsulating assembly 6a, 6b, obtained by the fusion of two layers of upper encapsulating material 6a and lower 6b, an assembly 4 of photovoltaic cells 5 taken between two layers of upper encapsulating material 6a and lower 6b, and a second layer 7 forming the rear face of the photovoltaic module 1 intended to be glued to the walkable area 2.

[0088] The two layers of encapsulating material 6a and 6b forming the encapsulating assembly, together with the possible intermediate layer 9 described later, form a relatively flexible structure that can be made from a single material or from several materials in case of chemical incompatibility.

[0089] According to the invention, the first layer 3 is made of a transparent polymer material and comprises a plurality of plates 8 independent of each other, each plate 8 being located opposite a photovoltaic cell 5, so as to form a discontinuous front face of the photovoltaic module 1.

[0090] The transparent polymer material of the first layer 3 can be chosen from, for example, polycarbonate (PC), polymethyl methacrylate (PMMA), ethylene tetrafluoroethylene (ETFE), or polyvinylidene fluoride (PVDF), among others. Furthermore, the thickness of the first layer 3 can be greater than 0.1 mm, and ideally between 0.5 and 6 mm. In this example, the first layer 3 consists of several 8 PMMA sheets, each measuring 162 x 162 mm and 3 mm thick.

[0091] Furthermore, the photovoltaic cells 5 are electrically interconnected with each other with a spacing s between two adjacent cells 5 of approximately 15 mm. The photovoltaic cells 5 can be so-called "crystalline" cells, that is, based on silicon crystals or silicon polycrystals, with a homojunction or heterojunction, and a thickness less than or equal to 250 µm. In addition, in this example, each plate 8 extends overlapping on either side of the underlying photovoltaic cell 5 by a distance of approximately 3 mm, so that the spacing between two adjacent plates 8 is equal to the spacing s between two adjacent cells 5 minus approximately 2 times 3 mm, or approximately 6 mm.

[0092] In addition, the stiffness of each layer of encapsulation material 6a and 6b is defined by a Young's modulus E at room temperature of the encapsulation material greater than or equal to 50 MPa, or even 75 MPa, or even 100 MPa, preferably greater than or equal to 200 MPa, and a thickness e of the layer 6a, 6b between 0.2 and 1 mm.

[0093] The encapsulation material layers 6a and 6b form an encapsulating assembly preferably chosen to be an ionomer such as the ionomer marketed under the name jurasol® ionomer of type DG3 by the company Jura-plast or the ionomer marketed under the name PV5414 by the company Du Pont, having a Young's modulus at room temperature greater than or equal to 200 MPa and a thickness of about 500 µm.

[0094] The second layer 7, forming the back face of the photovoltaic module 1, is made of a polymer material such as thermosetting resins like epoxy-based resins, transparent or opaque, or a composite material, for example, of the polymer / fiberglass type. In this example, the second layer 7 is made of a polymer / fiberglass composite material, specifically a polypropylene and fiberglass fabric with a fiberglass content of 60% by mass, such as the Thermopreg® fabric P-WRt-1490-PP60W marketed by Owens Corning Vetrotex, having a thickness of approximately 1 mm and a Young's modulus at room temperature of approximately 12 GPa.

[0095] Furthermore, an adhesive layer 11, also called a compatibilizing layer (its presence being justified in case of chemical incompatibility), is located between the second layer 7, forming the back face of the photovoltaic module 1, and the encapsulating assembly formed by the two layers of encapsulating material 6a and 6b on either side of the photovoltaic cell assembly 4 5. This adhesive or compatibilizing layer 11 allows the second layer 7 to be bonded to the lower layer of encapsulating material 6b. When using Thermopreg® fabric P-WRt-1490-PP60W for the second layer 7, the compatibilizing layer 11 is preferably chosen to be a Mondi TK41001 type film with a thickness of approximately 50 µm.

[0096] Furthermore, as can be seen on the figure 1, the photovoltaic module 1 also includes an intermediate layer 9 called "damping" located between the first layer 3 and the encapsulating assembly formed by the two layers of encapsulating material 6a and 6b on either side of the assembly 4 of photovoltaic cells 5.

[0097] The intermediate layer 9 allows the first layer 3 to be glued onto the upper encapsulation material layer 6a.

[0098] The intermediate layer 9, for example, consists of a standard encapsulant used in the photovoltaic field, such as ethylene-vinyl acetate (EVA) copolymer, a polyolefin, silicone, thermoplastic polyurethane, or polyvinyl butyral, among others. It can also consist of a liquid resin such as acrylic, silicone, or polyurethane, either one-component or two-component, that is heat-curable or photochemically bondable. Alternatively, it can consist of a pressure-sensitive adhesive (PSA).

[0099] In this example, the intermediate layer 9 consists of a thermoplastic film, namely thermoplastic polyurethane also known by the English acronym TPU, such as TPU Dureflex® A4700 marketed by Bayer or PX1001 marketed by American Polyfilm, with a thickness of approximately 380 µm.

[0100] The intermediate layer 9 serves two main functions. Firstly, it allows the first layer 3 to adhere to the upper encapsulation material layer 6a in cases where the two layers are not chemically compatible. Secondly, it creates a "damping" layer within the photovoltaic module 1, providing a degree of flexibility to improve the module's resistance to shocks and mechanical loads.

[0101] Furthermore, the photovoltaic structure assembly 10 according to the invention shown in the figure 1 It also includes a carriageway zone 2. The carriageway zone 2 can have variable rigidity. In this example, it corresponds specifically to an asphalt surface of the roadway type.

[0102] To allow the photovoltaic module 1 to be bonded to the road surface 2, the assembly 10 also includes a bonding layer 12. This bonding layer 12 consists of a bituminous adhesive that allows the module 1 to adhere to the pavement or road. In this example, it is a CoIFlex N type bitumen marketed by the company Colas, with a dosage of 1 kg / m². The use of a bituminous adhesive 12 combined with a composite material back face 7 of the module 1 can reinforce the back face 7 to prevent the risk of punctures to the photovoltaic cells 5 subjected to pedestrian and / or vehicle traffic on a rough pavement 2. The bituminous adhesive 12 thus acts as a protective binder, filling the interface between the pavement 2 and the back face 7 of the module 1.

[0103] Furthermore, although not represented on the figure 1The photovoltaic structure assembly 10 also includes a coating layer applied over the first layer 3, intended to facilitate the movement of pedestrians and / or vehicles.

[0104] The coating layer is non-opaque and has a textured and irregular outer surface, including an irregularly macrotextured and microtextured outer surface, with an average texture depth PMT measured according to standard NF EN 13036-1 between 0.2 mm and 3 mm and a PSV value according to standard NF EN 13043 of at least PSV 44, or even PSV 50, or even PSV 53.

[0105] We will now describe a method for making a set 10 of photovoltaic structure according to the invention.

[0106] The process includes a first step a) of hot rolling at a temperature of approximately 170°C and under vacuum (pressure less than or equal to 10 mbar) of the constituent layers 6a, 4, 6b, 11, and 7 of the photovoltaic module 1, excluding the first layer 3 and the intermediate layer 9. This first step a) of rolling is carried out for approximately 15 minutes in order to obtain a "laminate" of encapsulated photovoltaic cells 5. The rolling parameters, such as temperature, time, and pressure, may, however, depend on the encapsulating material used.

[0107] Then, the process includes a second step b) of hot rolling at a temperature of about 125°C and under vacuum of the "roll" obtained during the first step a) with the first layer 3 forming the front face of the photovoltaic module 1 using the intermediate layer 9. This second step b) is carried out for a period of about 30 minutes in order to obtain the photovoltaic module 1. Before the implementation of this second step b), the plates 8 of the first layer 3 can advantageously be treated using Corona treatment equipment in order to obtain a surface energy greater than or equal to 48 dyn / cm.

[0108] These first (a) and second (b) lamination steps are then followed by a step (c) of applying a coating layer to the first layer 3 to allow pedestrian and / or vehicle traffic, the coating layer being as described previously. Finally, a step (d) of fixing the photovoltaic module 1 to the trafficable area 2 forms the photovoltaic structure assembly 10. This fixing step is advantageously carried out using a bituminous adhesive applied between the trafficable area 2 and the module 1.

[0109] Tests were carried out with various photovoltaic modules 1, comprising from 3 to 40 photovoltaic cells 5, according to the process described above. The mechanical load resistance of these modules 1, bonded to a road surface 2, under pressures of up to 500 kN / m² in static and dynamic conditions, was demonstrated. For example, a photovoltaic module 1, consisting of three photovoltaic cells 5, showed no degradation after approximately 64,000 applications of a pressure of 500 kN / m².

[0110] Therefore, the photovoltaic module 1 can exhibit increased mechanical strength suitable for demanding applications in terms of mechanical stress, such as solar road systems, but also segmented flexibility due to the presence of a discontinuous front face 3, allowing it to take on different shapes to adapt to various types of surfaces, for example, uneven or imperfectly flat. Furthermore, the presence of a reinforced rear face 7 can improve the resistance to puncture of this rear face 7 of the module 1, such puncture resulting from the roughness of the substrate 2 to which the module 1 is applied and potentially leading to cracks in the photovoltaic cells 5 of the photovoltaic module 1.

[0111] Of course, the invention is not limited to the embodiment just described. Various modifications can be made to it by a person skilled in the art.

[0112] The expression "containing one" should be understood as synonymous with "containing at least one", unless otherwise specified.

Claims

1. Photovoltaic structure assembly (10), comprising: - a circulable zone (2), - a photovoltaic module (1) applied to the circulable zone (2), the photovoltaic module (1) comprising at least: - a first transparent layer (3) forming the front face of the photovoltaic module (1) intended to receive a luminous flux, - an assembly (4) of a plurality of photovoltaic cells (5) arranged side by side and electrically connected together, - an assembly (6a, 6b) encapsulating the plurality of photovoltaic cells (5), - a second layer (7) forming the rear face of the photovoltaic module (1), the encapsulating assembly (6a, 6b) and the assembly (4) of a plurality of photovoltaic cells (5) being situated between the first (3) and second (7) layers, and - a fixation layer (12), constituted notably of a bituminous adhesive or one or more acrylic resins, situated between the circulable zone (2) and the photovoltaic module (1), enabling the adherence of the photovoltaic module (1) to the circulable zone (2), characterised in that the first layer (3) is constituted of at least one transparent polymer material and comprises a plurality of panels (8) independent of each other, each panel (8) being situated facing at least one photovoltaic cell (5), so as to form a discontinuous front face of the photovoltaic module (1), and in that the rigidity of the encapsulating assembly (6a, 6b) is defined by a Young's modulus (E) of the encapsulation material greater than or equal to 75 MPa at ambient temperature and a thickness (e) of the encapsulating assembly (6a, 6b) comprised between 0.4 and 1 mm.

2. Assembly according to claim 1, characterised in that it comprises a covering layer, notably enabling the passage of pedestrians and / or vehicles, applied to the first layer (3) forming the front face of the photovoltaic module (1), the covering layer being non-opaque and having a textured and irregular outer surface, notably an irregularly macrotextured and microtextured outer surface, with a mean texture depth MTD measured according to the NF EN 13036-1 standard comprised between 0.2 mm and 3 mm and a PSV value according to the NF EN 13043 standard of at least PSV44, better PSV50, even better PSV53.

3. Assembly according to claim 1 or 2, characterised in that the circulable zone (2) is provided for the circulation of pedestrians and / or vehicles, being notably a roadway.

4. Assembly according to one of the preceding claims, characterised in that the encapsulation material of the layers forming the encapsulating assembly (6a, 6b) has a Young's modulus (E) at ambient temperature greater than or equal to 100 MPa, preferably greater than or equal to 150 MPa, preferably greater than or equal to 200 MPa, notably equal to 220 MPa.

5. Assembly according to any of the preceding claims, characterised in that the second layer (7) forming the rear face of the photovoltaic module (1) is constituted of at least one composite material, notably of the polymer / glass fibre type.

6. Assembly according to one of the preceding claims, characterised in that the rigidity of the second layer (7) forming the rear face of the photovoltaic module (1) is defined by a rigidity factor, corresponding to the Young's modulus (E) at ambient temperature of the material of the second layer (7) multiplied by the thickness of the second layer (7), comprised between 5 and 15 GPa.mm.

7. Assembly according to any of the preceding claims, characterised in that the spacing(s) between two neighbouring photovoltaic cells (5) is greater than or equal to 1 mm, notably comprised between 1 and 30 mm, and preferably greater than or equal to 3 mm, notably comprised between 10 and 20 mm.

8. Assembly according to any of the preceding claims, characterised in that the photovoltaic module (1) comprises a so-called "cushioning" intermediate layer (9) situated between the first layer (3) forming the front face of the photovoltaic module (1) and the assembly (6a, 6b) encapsulating the plurality of photovoltaic cells (5), enabling the assembly, notably by bonding, of the first layer (3) on the encapsulating assembly (6a, 6b).

9. Assembly according to claim 8, characterised in that the intermediate layer (9) is constituted of at least one polymer material, notably a thermoplastic or thermosetting polymer resin.

10. Assembly according to claim 8 or 9, characterised in that the rigidity of the intermediate layer (9) is defined by a Young's modulus (E) at ambient temperature of the material of the intermediate layer (9) less than or equal to 50 MPa and a thickness of the intermediate layer (9) comprised between 0.01 and 1 mm.

11. Assembly according to any of the preceding claims, characterised in that the photovoltaic module (1) comprises an adhesive layer (11) situated between the second layer (7) forming the rear face of the photovoltaic module (1) and the encapsulating assembly (6a, 6b) formed by two layers of encapsulation material (6a, 6b) on either side of the plurality of photovoltaic cells (5), enabling the assembly, notably by bonding, of the second layer (7) on the encapsulating assembly (6a, 6b).

12. Assembly according to any of the preceding claims, characterised in that the thickness of the first layer (3) forming the front face of the photovoltaic module (1) is greater than or equal to 0.1 mm, notably comprised between 0.5 and 6 mm.

13. Assembly according to any of the preceding claims, characterised in that the photovoltaic cells (5) are so-called "crystalline" cells, that is to say based on silicon crystals or silicon polycrystals.

14. Use, for the application thereof on a circulable zone (2), notably a roadway, of a photovoltaic module (1) comprising at least: - a first transparent layer (3) forming the front face of the photovoltaic module (1) intended to receive a luminous flux, - an assembly (4) of a plurality of photovoltaic cells (5) arranged side by side and electrically connected together, - an assembly (6a, 6b) encapsulating the plurality of photovoltaic cells (5), - a second layer (7) forming the rear face of the photovoltaic module (1), the encapsulating assembly (6a, 6b) and the assembly (4) of a plurality of photovoltaic cells (5) being situated between the first (3) and second (7) layers, the first layer (3) being constituted of at least one transparent polymer material and comprising a plurality of panels (8) independent of each other, each panel (8) being situated facing at least one photovoltaic cell (5), so as to form a discontinuous front face of the photovoltaic module (1), and the rigidity of the encapsulating assembly (6a, 6b) being defined by a Young's modulus (E) of the encapsulation material greater than or equal to 75 MPa at ambient temperature and a thickness (e) of the encapsulating assembly (6a, 6b) comprised between 0.4 and 1 mm, the photovoltaic module (1) being applied to the circulable zone (2) through the intermediary of a fixation layer (12), constituted notably of a bituminous adhesive or one or more acrylic resins.

15. Method for producing a photovoltaic structure assembly (10) according to any of claims 1 to 13, comprising at least the following four successive steps of: a) hot rolling at a temperature greater than 150°C of the assembly of the layers (6a, 4, 6b, 11, 7) constituting the photovoltaic module (1) apart from the first layer (3) forming the front face of the photovoltaic module (1) and a potential so-called "cushioning" intermediate layer (9), situated between the first layer (3) and the assembly (6a, 6b) encapsulating the plurality of photovoltaic cells, b) rolling at a temperature less than or equal to 150°C, preferably 125°C, of the first layer (3) forming the front face of the photovoltaic module (1), and the potential intermediate layer (9), on the layers (6a, 4, 6b, 11, 7) constituting the photovoltaic module (1) rolled together during the first step a), c) application of a covering layer on the first layer (3) forming the front face of the photovoltaic module (1), notably to enable the passage of pedestrians and / or vehicles, the covering layer being non-opaque and having a textured and irregular outer surface, notably an irregularly macrotextured and microtextured outer surface, with a mean texture depth MTD measured according to the NF EN 13036-1 standard comprised between 0.2 mm and 3 mm and a PSV value according to the NF EN 13043 standard of at least PSV44, better PSV50, even better PSV53, d) fixation of the photovoltaic module (1) on the circulable zone (2) to form the photovoltaic structure assembly (10), by means of a layer (12) for fixing the photovoltaic structure assembly (10), constituted notably of a bituminous adhesive or one or more acrylic resins.

16. Method for producing a photovoltaic structure assembly (10) according to any of claims 1 to 13, comprising at least the following three successive steps of: a) hot rolling at a temperature greater than or equal to 150°C of the assembly of the layers (3, 9, 6a, 4, 6b, 11, 7) constituting the photovoltaic module (1), b) application of a covering layer on the first layer (3) forming the front face of the photovoltaic module (1), notably to enable the passage of pedestrians and / or vehicles, the covering layer being non-opaque and having a textured and irregular outer surface, notably an irregularly macrotextured and microtextured outer surface, with a mean texture depth MTD measured according to the NF EN 13036-1 standard comprised between 0.2 mm and 3 mm and a PSV value according to the NF EN 13043 standard of at least PSV44, better PSV50, even better PSV53, c) fixation of the photovoltaic module (1) on the circulable zone (2) to form the photovoltaic structure assembly (10), by means of a layer (12) for fixing the photovoltaic structure assembly (10), constituted notably of a bituminous adhesive or one or more acrylic resins.