Photovoltaic module with barrier structure

Abstract

The invention relates to a photovoltaic device comprising a multilayer stack comprising: at least one photovoltaic cell; an encapsulation structure containing the at least one photovoltaic cell. Said encapsulation structure comprising a first face and a second opposite face; a first barrier structure formed by a single layer or several superimposed layers and arranged on said first or second face; a first composite reinforcement structure comprising a first polymer matrix filled with a first network of fibers; said first composite reinforcement structure being separated from the encapsulation structure by the first barrier structure; said first barrier structure having a water vapor transmission coefficient WVTR lower than that of the first composite reinforcement structure. Figure for abstract: Fig. 2

Description

Title of the invention: Photovoltaic module with barrier structure

[0001] Scope of application

[0002] The invention relates to the field of photovoltaic devices. More particularly, the invention relates to the construction stack of photovoltaic modules for powering a stratospheric, space or terrestrial vehicle and more generally for any field requiring lightweight photovoltaic modules.

[0003] Problem raised

[0004] The present invention relates to a photovoltaic device meeting the specific needs of lightweight photovoltaic panels, in particular for use in the stratosphere and in space. Traditional photovoltaic modules used on Earth and in space are designed with different structures, adapted to the environmental and technical constraints specific to each field.

[0005] For applications in the stratosphere and space, where lightness is essential due to strict aeronautical constraints, new module architectures are required, aiming for weights below 1 kg / m2. The environmental and technical constraints specific to these environments make the use of glass less appropriate in these architectures.

[0006] In order to minimize the weight of photovoltaic panels, a known solution is to use lightweight composite materials. In this context, a photovoltaic module comprises the following elements: one or more photovoltaic cells, an encapsulation structure, a reinforcing composite structure and an outer barrier layer, waterproof and UV-protective.

[0007] Photovoltaic cells are the basic components of photovoltaic modules. Photovoltaic cells are electronic devices that convert sunlight into electricity. They are usually made from semiconductors such as silicon, and they generate a direct electric current in response to an incident light ray.

[0008] The encapsulation structure is composed of an encapsulating material used to protect and insulate the photovoltaic cells. The encapsulant is generally composed of a transparent polymer, which encapsulates the photovoltaic cells. The encapsulant provides a bonding function, protection against mechanical shocks, while allowing sunlight to penetrate to the cells.

[0009] The composite reinforcement structure is arranged, by lamination for example, directly on the encapsulation structure. The composite reinforcement structure is made of reinforced materials to increase their mechanical strength. It is a structure comprising fibers, such as glass or carbon, which are incorporated into a polymer matrix to form a composite material. These reinforcing composites provide structural rigidity of the photovoltaic device combined with a light weight compatible with applications in space and stratospheric environments. Some composites also offer high transmission in the wavelengths of the solar spectrum of interest for photovoltaic conversion, which allows them to be used on the front panel of the module.

[0010] However, mechanical defects due to delamination at the interface between the composite reinforcement structure and the encapsulation structure were observed during the various robustness characterization tests of the photovoltaic modules described. Indeed, the composite reinforcement structure and the encapsulation structure may have structural incompatibilities at the interface. These structural incompatibilities may result from chemical incompatibilities between the polymers used, as well as from moisture captured by the reinforcement matrix before lamination. This moisture or these solvents may lead to the formation of bubbles and ultimately to delamination of the module during its aging. Delamination at this interface leads to a deterioration in the performance of the module and a reduction in its lifetime.Delamination can also be caused by mechanical stress, temperature variations, humidity, or similar environmental factors. This phenomenon compromises the efficiency of converting sunlight into electricity and can lead to premature failure of the photovoltaic module. Therefore, it is essential to develop solutions to prevent delamination and ensure the long-term reliability of photovoltaic modules.

[0011] In the context of the invention, the term "Water Vapor Transmission Rate" or WVTR means a measurement that quantifies the rate at which water vapor can pass through a material. WVTR is generally expressed in units of mass (g) per unit area (such as square meter) per unit time (such as day). For example, a typical WVTR value might be "1 g / m2 / day", meaning that one square meter of material will allow the passage of approximately 1 gram of water vapor per day. The commonly used standard for measuring WVTR is ASTM E96.

[0012] Prior art / State of the art restrictions

[0013] European patent EP3058597B1 relates to a photovoltaic module comprising at least one solar cell in an encapsulation structure. The module further comprises a composite reinforcement structure based on glass fibers in a matrix of a polymer. The composite reinforcement structure is arranged on the encapsulant, which increases the risk of delamination discussed previously.

[0014] Response to the problem and provision of solution

[0015] To overcome the limitations of existing solutions, the invention proposes a photovoltaic device comprising a barrier structure formed by a single layer or multiple layers, which separates the encapsulation structure from the composite reinforcement structure. The barrier structure is made of a first material having a water impermeability greater than that of the first composite reinforcement structure. The solution proposed according to the invention has several advantages compared to the state of the art.

[0016] The stacking structure according to the invention makes it possible to eliminate surface structural incompatibilities between the reinforcement matrix and the encapsulation structure. The introduction of barrier layers makes it possible to prevent these problems and to improve the durability of the module. The effectiveness of the barrier layers has been confirmed by tests carried out on modules subject to delamination during aerospace aging cycles.

[0017] In addition, the distance of the composite reinforcement structure from the photovoltaic cells makes it possible to increase the stiffness of the photovoltaic module without increasing its mass, which is particularly advantageous for space applications where the mass must be minimized to preserve the orbital altitude of the satellites. Thus, one of the major advantages of this solution is the reduction in the mass of the modules while gaining in strength, durability and stiffness. The lightness of the modules is essential in many fields, and this invention makes it possible to obtain stronger and more rigid modules without increasing their mass, thus offering a considerable benefit. After the introduction of the barrier structure according to the invention, the problem of delamination disappears, and the modules resist aerospace aging cycles.

[0018] Abstract / Claims

[0019] The subject of the invention is a photovoltaic device comprising a multilayer stack in a stacking direction. Said stack comprising: - at least one photovoltaic cell; - an encapsulation structure containing the at least one photovoltaic cell; said encapsulation structure comprising a first face and a second face opposite and extending parallel to a first plane orthogonal to the stacking direction; - a first barrier structure, formed by a single layer or several superimposed layers, and arranged on said first or second face; - a first composite reinforcement structure comprising a first polymer matrix loaded with a first network of fibers; said first composite reinforcement structure being separated from the encapsulation structure by the first barrier structure; said first barrier structure having a water vapor transmission coefficient WVTR lower than that of the first composite reinforcement structure.

[0020] According to a particular aspect of the invention, the first barrier structure has a water vapor transmission coefficient WVTR of less than 30 gm 2 / 24h.

[0021] According to a particular aspect of the invention, the first barrier structure has an optical transmittance greater than 85% in the wavelength range of 300 to 1200 nm.

[0022] According to a particular aspect of the invention, the first barrier structure has a glass transition temperature greater than 80°C or a thermal melting temperature greater than 80°C.

[0023] According to a particular aspect of the invention, the first barrier structure has a dielectric strength greater than IkV / mm.

[0024] According to a particular aspect of the invention, the first barrier structure has a thickness in a stacking direction less than or equal to 2 mm.

[0025] According to a particular aspect of the invention, the first polymer matrix is ​​thermosetting or thermoplastic.

[0026] According to a particular aspect of the invention, the first polymer matrix is ​​an epoxy resin.

[0027] According to a particular aspect of the invention, the fibers are glass fibers.

[0028] According to a particular aspect of the invention, the first composite reinforcement structure comprises at least one opening made so as to expose at least one photovoltaic cell to light through said opening.

[0029] According to a particular aspect of the invention, the first barrier structure is formed by a layer or a stack of layers of polycarbonate or polyethylene terephthalate or polyamide or fluorinated polymer, in particular polyvinyl fluoride or polyvinylidene fluoride, or ethylene tetrafluoroethylene or ethylene chlorotrifluoroethylene or polychlorotrifluoroethylene or fluorinated ethylene propylene.

[0030] According to a particular aspect of the invention, the photovoltaic device further comprises, when the barrier structure is arranged on the first face: - a second barrier structure arranged on the second face of the encapsulation structure opposite the first face; said second barrier structure being formed by a single layer or several superimposed layers; - a second composite reinforcement structure comprising a second polymer matrix loaded with a second network of fibers; - said second composite reinforcement structure being separated from the encapsulation structure by the second barrier structure; said second barrier structure having a water vapor transmission coefficient WVTR lower than that of the second composite reinforcement structure.

[0031] According to a particular aspect of the invention, the second barrier structure and the first barrier structure are formed by the same material and have the same thickness.

[0032] According to a particular aspect of the invention, the second composite reinforcement structure has a Young's modulus greater than or equal to that of the first composite reinforcement structure.

[0033] According to a particular aspect of the invention, the second polymer matrix and the first polymer matrix are identical. The second fiber network and the first fiber network are formed by the same material.

[0034] According to a particular aspect of the invention, the second fiber network is made of carbon fibers. Detailed Description

[0035] Other characteristics and advantages of the present invention will appear more clearly on reading the description which follows in relation to the following appended drawings.

[0036] [Fig-1] [Fig.l] illustrates a sectional view of the photovoltaic device according to a first embodiment of the invention.

[0037] [Fig.2] [Fig.2] illustrates a sectional view of the photovoltaic device according to a second embodiment of the invention.

[0038] [Fig.3a] [Fig.3a] illustrates a top view of a first example of the front face of the photovoltaic device according to the invention.

[0039] [Fig.3b] [Fig.3b] illustrates a top view of a second example of the face front of the photovoltaic device according to the invention.

[0040] [Fig.3c] [Fig.3c] illustrates a top view of a third example of the front face of the photovoltaic device according to the invention.

[0041] [Fig.l] illustrates a sectional view of the photovoltaic device DI according to a first embodiment of the invention. The photovoltaic device DI comprises a laminated stack in a stacking direction Z. The laminated stack comprises one or more photovoltaic cells 11, 12 and 13; an encapsulation structure 20; a first barrier structure 30 and a first reinforcing composite structure 40. The first barrier structure 30 separates the encapsulation structure 20 from the first reinforcing composite structure 40. The insertion of the first barrier structure 30 makes it possible to avoid the formation of a common interface between the encapsulation structure 20 and the first reinforcing composite structure 40.

[0042] The first barrier structure 30 is formed by a single layer or a multilayer stack. As an illustrative and non-limiting example, we will describe a barrier structure 30 formed by a single layer without excluding a first multilayer barrier structure 30.

[0043] In the described embodiment, the photovoltaic device DI comprises several photovoltaic cells 11, 12 and 13 as a non-limiting illustrative example. The photovoltaic cells 11, 12 and 13 are electrically interconnected via connection means 101, 102 so as to form a matrix. By way of example, the connection means are rods, ribbons, wires or conductive adhesives allowing series mounting of the photovoltaic cells 11, 12 and 13. The photovoltaic cells 11, 12 and 13 are in the form of thin plates, advantageously coplanar along the plane (X, Y) orthogonal to the stacking direction Z. The photovoltaic cells 11, 12 and 13 are made of silicon or perovskites or a type IILV semiconductor or organic polymer semiconductors.

[0044] The encapsulation structure 20 is a structure made of a transparent polymer in the operating wavelength range of the module. The encapsulation structure 20 contains the photovoltaic cells 11, 12 and 13 and the interconnections 101, 102 to ensure their protection against humidity, contaminants and mechanical shocks, while allowing sunlight to penetrate to the cells. In the illustrated example, the encapsulation structure 20 constitutes a block which surrounds the matrix of photovoltaic cells 11, 12 and 13.

[0045] The encapsulation structure 20 is advantageously formed from a first and a second layer of encapsulation polymer material between which a matrix of photovoltaic cells 11, 12 and 13 is interposed. During the step of assembling the stack (in particular by lamination), the layers of encapsulation polymer material melt and encompass / encapsulate the photovoltaic cells, at the same time as adhesion is created at all the interfaces between the layers constituting the stack. The two layers of encapsulation polymer material forming the encapsulation structure 20 extend along planes orthogonal to the stacking direction Z.

[0046] The encapsulation structure 20 comprises a first face 21 intended to receive light and extending along a first plane orthogonal to the stacking direction Z. In the context of the description of the invention, the first face 21 is on the side of the “front face” of the module. The terms “front face” and “rear face” mean the external faces of the photovoltaic device. The front face corresponds to the external face of the device intended to receive light. The rear face corresponds to the external face of the support on which the photovoltaic device DI rests mechanically. The encapsulation structure 20 also comprises a second face 22 opposite the first face 21 and which extends parallel to the first face 21. In the context of the description of the invention, the second face 22 is on the side of the “rear face”.

[0047] According to an alternative embodiment, the first encapsulation structure 20 and the first barrier structure 30 are on the rear face side.

[0048] By way of example, the encapsulation structure 20 is made of a material polymer encapsulation material, of thermosetting or thermoplastic type. The polymer encapsulation material is, for example, chosen from: acid copolymers, ionomers, poly(ethylene-vinyl acetate) (EVA), vinyl acetals, such as polyvinyl butyrals (PVB), polyurethanes, polyvinyl chlorides, polyethylenes, such as linear low density polyethylenes, polyolefin elastomer copolymers, copolymers of α-olefins 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.

[0049] Concerning the dimensioning of the encapsulation structure 20, the distance dl between on the one hand the photovoltaic cells 11, 12 and 13 and on the other hand the first face 21 is greater than 20 pm.

[0050] The first barrier structure 30 is directly in contact with the first face 21 (on the front face side) of the encapsulation structure 20. The first barrier structure 30 is made of a first material. The first material has a water vapor transmission coefficient WVTR lower than that of the first composite reinforcement structure 40. This makes it possible to protect the encapsulant from the diffusion of water or volatile products and thus eliminate delamination problems at the first face 21. Advantageously, the first material constituting the first barrier structure 30 has a water vapor transmission coefficient WVTR less than or equal to 30 gm 2 / 24h, preferably less than or equal to 10 g.m2 / 24h. The thickness of the barrier structure 30 is less than 2mm, preferably between 10pm and 50pm, which makes it possible to obtain the barrier effect while ensuring the mechanical robustness of the device.

[0051] In addition, the first barrier structure 30 has a transmittance greater than 85%, preferably greater than 90%, in the wavelength range of 300 to 1200 nm. This allows the transmission of a ray incident on the first face 21 of the photovoltaic device D1 through the first barrier structure 30 to the photovoltaic cells 11, 12 and 13.

[0052] The first barrier structure 30 also has a glass transition temperature Tg greater than 80°C, preferably greater than 120°C. The glass transition temperature Tg is understood to mean the temperature value delimiting the passage of the material from a rubbery state to a glassy, ​​solid state. This makes it possible to improve the thermal resistance of the photovoltaic device D1 and more particularly the interfaces of the first barrier structure 30 in the context of the extreme thermal conditions of the space domain and the stratospheric domain.

[0053] The first barrier structure 30 also has a dielectric strength greater than IkV / mm, preferably greater than 100 kV / mm. The dielectric strength is measured according to standard NF EN 60243-1. This improves the electrical insulation of the encapsulation structure 20 and thus of the photovoltaic cells 11, 12 and 13.

[0054] In order to obtain all of the aforementioned mechanical, electrical, thermal, optical and impermeability characteristics, the first material constituting the first barrier structure 30 is chosen, by way of non-limiting illustrative example, from: polycarbonate (PC), polyethylene terephthalate (PET), polyamide (PA), a fluorinated polymer, in particular polyvinyl fluoride (PVF) or polyvinylidene fluoride (PVDF), ethylene tetrafluoroethylene (ETFE), ethylene chlorotrifluoroethylene (ECTFE), polychlorotrifluoroethylene (PCTFE), and / or fluorinated ethylene propylene (FEP). According to a particular aspect of the invention, the first barrier structure 30 is produced by a stack of several superimposed barrier layers of materials chosen from the list of aforementioned materials to form a multilayer barrier structure.

[0055] The first composite reinforcement structure 40 is assembled with the first barrier structure 30, generally during a lamination step of the stack. The first barrier structure 30 thus separates the first composite reinforcement structure 4 from the encapsulation structure 20. This makes it possible to eliminate delamination problems between the first composite reinforcement structure 4 and the encapsulation structure 20.

[0056] The first composite reinforcement structure 40 comprises a first polymer matrix 42 loaded with a first fiber network 4L. The first composite reinforcement structure 40 has a Young's modulus greater than 5000 MPa, preferably greater than 15000 MPa. In addition, the first composite reinforcement structure 40 has a surface mass less than 50g / m2 with a thickness between 20pm and 150pm. The combination of the characteristics relating to the stiffness and the surface mass of the first composite reinforcement structure 40 makes it possible to ensure structural rigidity of the photovoltaic device DI while maintaining a light weight compatible with the fields of application in space and the stratospheric.

[0057] The first composite reinforcement structure 40 is assembled with the side of the front face of the photovoltaic device D1, generally by lamination. The first composite reinforcement structure 40 has an optical transmittance greater than 80%, preferably greater than 85%, in the wavelength range of 300 to 1200 nm.

[0058] The first composite reinforcement structure 40 comprises a thermosetting matrix or thermoplastic matrix resin. As an illustrative and non-limiting example, the first fiber network 41 is for example a glass fiber network, and the first polymer matrix 42 is epoxy. Alternatively, the first polymer matrix 42 is made of polyurethane or polymethyl methacrylate PMMA or cyanate esters or polycarbonate or polyethylene terephthalate PET or thermoplastic polyurethane TPU.

[0059] It is added that the stacking structure according to the invention makes it possible to increase the stiffness of the lightweight modules. By separating the composite reinforcement structure from the photovoltaic cells, the stiffness of the module is increased proportionally to the square of the distance d2 which separates them. For example, the distance d2 is less than or equal to 75 pm. Consequently, it is possible to increase the stiffness of the photovoltaic device DI without increasing its mass, which is particularly advantageous for space applications where the mass must be minimized to preserve the orbital altitude of the satellites.

[0060] According to a particular aspect of the invention, the first composite reinforcement structure 40 comprises a first network of glass fibers 41 occupying a central zone along the plane (X,Y) orthogonal to the stacking direction and a network of peripheral carbon fibers occupying the periphery of the first composite reinforcement structure 40 along the plane (X,Y). The central zone corresponds to the location of the matrix of photovoltaic cells 11, 12 and 13 intended to receive the incident light. The glass fibers have sufficient transparency to allow the incident light to pass towards said matrix. On the peripheral zone, the carbon fibers have better mechanical robustness than the glass fibers, making it possible to improve the overall robustness of the photovoltaic device DI.

[0061] Generally speaking, the stacking structure according to the first embodiment makes it possible to obtain the following advantages: an elimination of the delamination problem at the interface with the encapsulation structure, an increase in the stiffness of the photovoltaic device without increasing its mass; and an optimization of the transparency of the stack on the front face side allowing the maintenance of high energy efficiency.

[0062] [Fig. 2] illustrates a sectional view of the photovoltaic device DI according to a second embodiment of the invention. The characteristics and technical advantages described for the first embodiment remain valid for the second embodiment. The second embodiment of the invention differs from the first embodiment by the addition of a second barrier structure 50 and a second composite reinforcement structure 60 on the rear face side.

[0063] The second barrier structure 50 is formed by a single layer or a multilayer stack. As an illustrative and non-limiting example, we will describe a second barrier structure 50 formed by a single layer without excluding the use of a second multilayer barrier structure 50.

[0064] The photovoltaic device DI further comprises a second barrier structure 50 arranged on a second face 22 of the encapsulation structure 20 opposite the first face 21. The second face 22 corresponds to the rear face of the photovoltaic device D1. The second barrier structure 50 is made of a second material. The second composite reinforcement structure 60 comprises a second fiber network 61 made of a second resin 62. Said second composite reinforcement structure 40 is separated from the encapsulation structure 20 by the second barrier structure 50. The second material has a water vapor transmission coefficient WVTR lower than that of the second composite reinforcement structure 60. This makes it possible to improve, in a similar manner to the front face, the mechanical robustness of the device on the rear face side while eliminating delamination problems on this side.

[0065] According to a particular aspect of the invention, the second barrier structure 50 is identical to the first barrier structure 30 and the second composite reinforcement structure 60 is identical to the first composite reinforcement structure 40.

[0066] Alternatively, the second barrier structure 50 has the same mechanical, electrical, thermal and impermeability characteristics described for the first barrier structure 30, but has an optical transmittance lower than that of the first barrier structure 30. Similarly, the second composite reinforcement structure 60 has: on the one hand an optical transmittance lower than that of the first composite reinforcement structure 40; on the other hand a Young's modulus higher than that of the first composite reinforcement structure 40. This makes it possible to optimize the structure of the stack forming the photovoltaic device D1: - on the rear side, mechanical robustness is maximized; - on the front side, mechanical robustness is improved without degrading optoelectronic performance; - on both the front and rear sides the delamination problem is eliminated.

[0067] As a non-limiting illustrative example, the second material forming the second barrier structure 50 is chosen from: polycarbonate (PC), polyethylene terephthalate (PET), polyamide (PA), a fluoropolymer, in particular polyvinyl fluoride (PVF) or polyvinylidene fluoride (PVDF), ethylene tetrafluoroethylene (ETFE), ethylene chlorotrifluoroethylene (ECTFE), polychlorotrifluoroethylene (PCTFE), trifluoroethylene (TFE) and / or fluorinated ethylene propylene (FEP). According to a particular aspect of the invention, the second barrier structure 50 is produced by a stack of several superimposed barrier layers of materials chosen from the list of aforementioned materials to form a multilayer barrier structure.

[0068] The second composite reinforcement structure 50 is a thermosetting matrix or a thermoplastic matrix. Advantageously, the second fiber network 61 is, for example, a carbon fiber network, and the second resin 62 is epoxy. Alternatively, the second resin 62 is made of polyurethane or polymethyl methacrylate PMMA or cyanate esters or polycarbonate or polyethylene terephthalate. PET or thermoplastic polyurethane TPU.

[0069] [Fig.3a] illustrates a top view of a first example of the front face of the photovoltaic device DI according to the invention. In this embodiment, the composite reinforcement structure 40 comprises a central opening 400 along the plane (X,Y) orthogonal to the stacking direction Z. The central opening 400 allows the photovoltaic cells 11, 12, 13, 14, 15, 16 to receive a higher light intensity since the light rays no longer have to pass through the composite structure in this area. The composite reinforcement structure 40 covers only a peripheral area along the plane (X,Y) orthogonal to the stacking direction Z. This makes it possible to improve the exposure of the photovoltaic cells to light and thus increase the energy efficiency of the photovoltaic device DI. Advantageously, the composite reinforcement structure 40 covering only a peripheral area comprises a network of carbon fibers.This improves the mechanical robustness of the structure without impacting the exposure of the photovoltaic cells.

[0070] [Fig.3b] illustrates a top view of a second example of the front face of the photovoltaic device DI according to the invention. In this embodiment, the composite reinforcement structure 40 comprises a plurality of openings 401 to 406 along the plane (X,Y) orthogonal to the stacking direction Z. Each opening 401 to 406 reveals a photovoltaic cell 11 to 16 associated with said opening. This makes it possible to improve the exposure of the photovoltaic cells to light and thus increase the energy efficiency of the photovoltaic device DI. Advantageously, the composite reinforcement structure 40 comprises a network of carbon fibers. This makes it possible to improve the mechanical robustness of the structure without impacting the exposure of the photovoltaic cells.

[0071] [Fig.3c] illustrates a top view of a third example of the front face of the photovoltaic device DI according to the invention. In this embodiment, the composite reinforcement structure 40 covers the entire surface which extends parallel to the plane (X, Y). In this case, the first composite reinforcement structure 40 advantageously comprises a network of glass fibers.

[0072] All of the characteristics described for the first composite reinforcement structure 40 with FIGS. 3a, 3b and 3c are also compatible with the second composite reinforcement structure 60 of the rear face.

Claims

Claims

1. Photovoltaic device (Dl) comprising a multilayer stack in a stacking direction (Z); said stack comprising: - at least one photovoltaic cell (11, 12, 13); - an encapsulation structure (20) containing the at least one photovoltaic cell (11, 12); said encapsulation structure (20) comprising a first face (21) and a second face (22) opposite and extending parallel to a first plane orthogonal to the stacking direction (Z); - a first barrier structure (30) formed by a single layer or several superimposed layers and arranged on said first or second face (21, 22); - a first composite reinforcement structure (40) comprising a first polymer matrix (42) loaded with a first fiber network (41); said first composite reinforcement structure (40) being separated from the encapsulation structure (20) by the first barrier structure (30);said first barrier structure (30) having a water vapor transmission coefficient WVTR lower than that of the first reinforcing composite structure (40).;

2. Photovoltaic device (Dl) according to claim 1 wherein the first barrier structure has a water vapor transmission coefficient WVTR of less than 30 gm 2 / 24h.

3. A photovoltaic device (Dl) according to any one of claims 1 or 2 wherein the first barrier structure has an optical transmittance greater than 85% in the wavelength range of 300 to 1200 nm.

4. A photovoltaic device (Dl) according to any one of claims 1 to 3 wherein the first barrier structure has a glass transition temperature greater than 80°C or a thermal melting temperature greater than 80°C.

5. Photovoltaic device (Dl) according to any one of claims 1 to 4 wherein the first barrier structure has a dielectric strength greater than IkV / mm.

6. Photovoltaic device (Dl) according to any one of the claims- indications 1 to 5 in which the first barrier structure has a thickness in a stacking direction (Z) less than or equal to 2 mm.

7. Photovoltaic device (Dl) according to any one of claims 1 to 6 wherein the first polymer matrix (40) is thermosetting or thermoplastic.

8. A photovoltaic device (Dl) according to any one of claims 1 to 7 wherein the first polymer matrix (42) is an epoxy resin.

9. Photovoltaic device (Dl) according to any one of claims 1 to 8, the fibers (41) are glass fibers.

10. Photovoltaic device (Dl) according to any one of claims 1 to 9 wherein the first composite reinforcing structure (40) comprises at least one opening (400, 401, 402, 403, 404, 405, 406) made so as to expose at least one photovoltaic cell (11, 12, 13) to light through said opening.

11. Photovoltaic device (Dl) according to any one of claims 1 to 10 in which the first barrier structure (30) is formed by a layer or a stack of layers of polycarbonate or polyethylene terephthalate or polyamide or fluorinated polymer, in particular polyvinyl fluoride or polyvinylidene fluoride, or ethylene tetrafluoroethylene or ethylene chlorotrifluoroethylene or polychlorotrifluoroethylene or fluorinated ethylene propylene.

12. Photovoltaic device (Dl) according to any one of claims 1 to 11 wherein the barrier structure (30) is arranged on the first face (21); the photovoltaic device (Dl) further comprising: - a second barrier structure (50) arranged on the second face (22) of the encapsulation structure (20) opposite the first face (21); said second barrier structure (50) being formed by a single layer or several superimposed layers; - a second composite reinforcement structure (60) comprising a second polymer matrix (62) loaded with a second network of fibers (61); - said second composite reinforcement structure (60) being separated from the encapsulation structure (20) by the second barrier structure (50); said second barrier structure (30) having a water vapor transmission coefficient WVTR lower than that of the second reinforcing composite structure (60).

13. Photovoltaic device (Dl) according to claim 12 wherein the second barrier structure (50) and the first barrier structure (30) are formed by the same material and have the same thickness.

14. Photovoltaic device (Dl) according to any one of claims 12 or 13 wherein the second composite reinforcement structure (60) has a Young's modulus greater than or equal to that of the first composite reinforcement structure (40).

15. Photovoltaic device (Dl) according to any one of claims 12 or 13 wherein: - the second polymer matrix (62) and the first polymer matrix (42) are identical; - the second fiber network (61) and the first fiber network (41) are formed by the same material.

16. Photovoltaic device (Dl) according to any one of claims 12 to 14 wherein the second fiber network (61) is made of carbon fibers.

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