ASSEMBLY COMPRISING A PHOTOVOLTAIC MODULE APPLIED TO A CIRCULABLE ZONE

Abstract

A photovoltaic structure including an assembly of plural photovoltaic cells arranged side by side and electrically connected together, and an assembly encapsulating the plural photovoltaic cells. The encapsulating assembly and assembly of plural photovoltaic cells is situated between first and second layers, and a fixation layer situated between a circulable zone and a photovoltaic module, enabling adherence of the photovoltaic module to the circulable zone. The first layer includes at least one transparent polymer material and plural panels independent of each other, each panel situated facing at least one photovoltaic cell, to form a discontinuous front face of the photovoltaic module, and rigidity of the encapsulating assembly is defined by a Young's modulus of the encapsulation material greater than or equal to 75 MPa at ambient temperature and a thickness of the encapsulating assembly is between 0.4 and 1 mm.

Claims

1-16. (canceled)

17: A photovoltaic structure assembly, comprising: a circulable zone; a photovoltaic module applied to the circulable zone; the photovoltaic module comprising: a first transparent layer forming a front face of the photovoltaic module configured to receive a luminous flux, an assembly of a plurality of photovoltaic cells arranged side by side and electrically connected together, an assembly encapsulating the plurality of photovoltaic cells, and a second layer forming a rear face of the photovoltaic module, the encapsulating assembly and the assembly of a plurality of photovoltaic cells being situated between the first and second layers; and a fixation layer, including a bituminous adhesive or one or more acrylic resins, situated between the circulable zone and the photovoltaic module, enabling adherence of the photovoltaic module to the circulable zone, wherein the first layer includes at least one transparent polymer material and a plurality of panels independent of each other, each panel being situated facing at least one photovoltaic cell, to form a discontinuous front face of the photovoltaic module, and wherein rigidity of the encapsulating assembly is defined by a Young's modulus of the encapsulation material greater than or equal to 75 MPa at ambient temperature and a thickness of the encapsulating assembly is between 0.4 and 1 mm.

18: An assembly according to claim 17, further comprising a covering layer, applied to the first layer forming the front face of the photovoltaic module, the covering layer being non-opaque and having a textured and irregular outer surface, with a mean texture depth MTD measured according to the NF EN 13036-1 standard between 0.2 mm and 3 mm and a PSV value according to the NF EN 13043 standard of at least PSV.sub.44.

19: An assembly according to claim 17, wherein the circulable zone is provided for circulation of pedestrians and/or vehicles.

20: An assembly according to claim 17, wherein the encapsulation material of the layers forming the encapsulating assembly has a Young's modulus at ambient temperature greater than or equal to 100 MPa.

21: An assembly according to claim 17, wherein the second layer forming the rear face of the photovoltaic module includes at least one composite material.

22: An assembly according to claim 17, wherein the rigidity of the second layer forming the rear face of the photovoltaic module is defined by a rigidity factor, corresponding to the Young's modulus at ambient temperature of the material of the second layer multiplied by the thickness of the second layer, between 5 and 15 GPa.Math.mm.

23: An assembly according to claim 17, wherein spacing between two neighbouring photovoltaic cells is greater than or equal to 1 mm.

24: An assembly according claim 17, wherein the photovoltaic module comprises an intermediate layer situated between the first layer forming the front face of the photovoltaic module and the assembly encapsulating the plurality of photovoltaic cells, enabling assembly of the first layer on the encapsulating assembly.

25: An assembly according to claim 24, wherein the intermediate layer includes at least one polymer material.

26: An assembly according to claim 24, wherein the rigidity of the intermediate layer is defined by a Young's modulus at ambient temperature of the material of the intermediate layer less than or equal to 50 MPa and a thickness of the intermediate layer between 0.01 and 1 mm.

27: An assembly according to claim 17, wherein the photovoltaic module further comprises an adhesive layer situated between the second layer forming the rear face of the photovoltaic module and the encapsulating assembly formed by two layers of encapsulation material on either side of the plurality of photovoltaic cells, enabling assembly of the second layer on the encapsulating assembly.

28: An assembly according to claim 17, wherein the thickness of the first layer forming the front face of the photovoltaic module is greater than or equal to 0.1 mm.

29: An assembly according to claim 17, wherein the photovoltaic cells are based on silicon crystals or silicon polycrystals.

30: Use, for application thereof on a circulable zone of a photovoltaic module comprising: a first transparent layer forming a front face of the photovoltaic module configured to receive a luminous flux; an assembly of a plurality of photovoltaic cells arranged side by side and electrically connected together; an assembly encapsulating the plurality of photovoltaic cells; a second layer forming a rear face of the photovoltaic module, the encapsulating assembly and the assembly of a plurality of photovoltaic cells being situated between the first and second layers, the first layer including at least one transparent polymer material and including a plurality of panels independent of each other, each panel being situated facing at least one photovoltaic cell, to form a discontinuous front face of the photovoltaic module, and rigidity of the encapsulating assembly being defined by a Young's modulus of the encapsulation material greater than or equal to 75 MPa at ambient temperature and a thickness of the encapsulating assembly is between 0.4 and 1 mm, the photovoltaic module being applied to the circulable zone through an intermediary of a fixation layer, including a bituminous adhesive or one or more acrylic resins.

31: A method for producing a photovoltaic structure assembly according to claim 17, comprising: a) hot rolling at a temperature greater than 150 C. of an assembly of the layers constituting the photovoltaic module apart from the first layer forming the front face of the photovoltaic module and a potential intermediate layer, situated 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., of the first layer forming the front face of the photovoltaic module, and the intermediate layer, on the layers constituting the photovoltaic module rolled together during a); c) application of a covering layer on the first layer forming the front face of the photovoltaic module, the covering layer being non-opaque and having a textured and irregular outer surface with a mean texture depth MTD measured according to the NF EN 13036-1 standard between 0.2 mm and 3 mm and a PSV value according to the NF EN 13043 standard of at least PSV.sub.44; d) fixing the photovoltaic module on the circulable zone to form the photovoltaic structure assembly, by a layer for fixing the photovoltaic structure assembly.

32: A method for producing a photovoltaic structure assembly according to claim 17, comprising: a) hot rolling at a temperature greater than or equal to 150 C. of an assembly of the layers constituting the photovoltaic module; b) application of a covering layer on the first layer forming the front face of the photovoltaic module, the covering layer being non-opaque and having a textured and irregular outer surface with a mean texture depth MTD measured according to the NF EN 13036-1 standard between 0.2 mm and 3 mm and a PSV value according to the NF EN 13043 standard of at least PSV.sub.44; c) fixing the photovoltaic module on the circulable zone to form the photovoltaic structure assembly, by a layer for fixing the photovoltaic structure assembly.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0101] The invention will be better understood on reading the detailed description that follows of an example of non-limiting implementation thereof and be examining the single FIGURE, schematic and partial, of the appended drawing, illustrating, in section and in exploded view, an example of embodiment of a photovoltaic structure assembly in accordance with the invention.

[0102] In this single FIGURE, the different parts are not necessarily represented according to a uniform scale, in order to make the FIGURE more legible.

DETAILED DESCRIPTION OF A PARTICULAR EMBODIMENT

[0103] Reference is made hereafter to FIG. 1, illustrating in section and in exploded view an example of embodiment of a photovoltaic structure assembly 10 in accordance with the invention.

[0104] It should be noted that FIG. 1 corresponds to an exploded view of the photovoltaic structure assembly 10 before the rolling steps of the method according to the invention. Once the rolling steps have been carried out, the different layers are in reality superimposed on each other, but also a little deformed such that at least the panels 8 of the first layer 3 are pushed into the assembly formed by the intermediate layer 9 and the encapsulating assembly 6a, 6b which deform. The rolling steps ensure a hot, vacuum pressing. Depending on the thicknesses of the different layers, the panels 8 may be flush or not on the photovoltaic module 1, the material of the intermediate layer 9 and perhaps that of the encapsulating assembly 6a, 6b also being able to fill at least a part of the spaces between the panels 8.

[0105] As explained previously, the photovoltaic module 1 in accordance with the invention is designed to be sufficiently flexible in order to be able to apply it, notably by bonding, on a circulable zone 2, in particular a roadway, which can have a surface roughness, in other words not necessarily flat and smooth. In addition, the photovoltaic module 1 in accordance with the invention is also provided to withstand static or dynamic pressures that can go up to 1500 kN/m.sup.2, or even 5000 kN/m.sup.2. The circulable zone 2 is advantageously sufficiently rigid so as not to deform when the same stress is applied as that applied to the photovoltaic module 1.

[0106] As may thus be seen in FIG. 1, the photovoltaic module 1 comprises a first transparent layer 3 forming the front face of the module 1 intended to receive a luminous flux, an encapsulating assembly 6a, 6b, obtained by the melting of two layers of upper 6a and lower 6b encapsulation material, an assembly 4 of photovoltaic cells 5 taken between two layers of upper 6a and lower 6b encapsulation material, and a second layer 7 forming the rear face of the photovoltaic module 1 intended to be bonded to the circulable zone 2.

[0107] The two layers of encapsulation material 6a and 6b forming the encapsulating assembly, as well as the potential intermediate layer 9 described hereafter, form a relatively supple structure which can be produced from a single material or from several materials in the event of chemical incompatibility.

[0108] An accordance with the invention, the first layer 3 is constituted of a transparent polymer material and comprises a plurality of panels 8 independent of each other, each panel 8 being situated facing a photovoltaic cell 5, so as to form a discontinuous front face of the photovoltaic module 1.

[0109] The transparent polymer material of the first layer 3 may for example be selected from polycarbonate (PC), polymethyl methacrylate (PMMA), ethylene tetrafluoroethylene (ETFE), or polyvinylidene fluoride (PVDF), among others. In addition, the thickness of the first layer 3 may be greater than 0.1 mm, and ideally comprised between 0.5 and 6 mm. In this example, the first layer 3 is thus constituted of several panels 8, of dimensions equal to 162162 mm, of PMMA of thickness equal to 3 mm.

[0110] Furthermore, the photovoltaic cells 5 are interconnected electrically to each other with a spacing s between two neighbouring cells 5 equal to around 15 mm. The photovoltaic cells 5 may be so-called crystalline cells, that is to say based on silicon crystals or silicon polycrystals, with a homojunction or heterojunction, and of thickness less than or equal to 250 m. In addition, in this example, each panel 8 extends in superposition on either side of the underlying photovoltaic cell 5 over a distance of around 3 mm, such that the spacing between two adjacent panels 8 is here equal to the spacings between two neighbouring cells 5 reduced by around 2 times 3 mm, i.e. around 6 mm.

[0111] Moreover, the rigidity of each layer of encapsulation material 6a and 6b is defined by a Young's modulus E of the encapsulation material at ambient temperature greater than or equal to 50 MPa, or even 75 MPa, or instead even 100 MPa, preferably greater than or equal to 200 MPa, and a thickness e of the layer 6a, 6b comprised between 0.2 and 1 mm.

[0112] The layers of encapsulation material 6a and 6b form an encapsulating assembly preferentially selected to be an ionomer such as the ionomer sold under the name of Jurasol of DG3 type by the firm Jura-plant or the ionomer sold under the name PV5414 by the firm Du Pont, having a Young's modulus at ambient temperature greater than or equal to 200 MPa and a thickness of around 500 m.

[0113] The second layer 7 forming the rear face of the photovoltaic module 1 is for its part constituted of a polymer material such as thermosetting resins such as epoxy based resins, transparent or not, or a composite material, for example of the polymer/glass fibre type. In this example, the second layer 7 is constituted of a composite material of the polymer/glass fibre type, notably a fabric based on polypropylene and glass fibres with a glass fibre content of 60% by weight, such as Thermopreg fabric P-WRt-1490-PP60W sold by the firm Owens Corning Vetrotex, having a thickness of around 1 mm and a Young's modulus at ambient temperature of around 12 GPa.

[0114] Furthermore, an adhesive layer 11, or instead compatibilising layer (its presence being justified in the event of chemical incompatibility), is situated between the second layer 7 forming the rear face of the photovoltaic module 1 and the encapsulating assembly formed by the two layers of encapsulation material 6a and 6b on either side of the assembly 4 of photovoltaic cells 5. This adhesive or compatibilising layer 11 enables the bonding of the second layer 7 on the lower layer of encapsulation material 6b. In the case of the use of Thermopreg fabric P-WRt-1490-PP60W for the second layer 7, the compatibilising layer 11 is preferentially selected to be a film of Mondi TK41001 type having a thickness of around 50 m.

[0115] In addition, as may be seen in FIG. 1, the photovoltaic module 1 also comprises a so-called cushioning intermediate layer 9 situated between the first layer 3 and the encapsulating assembly formed by the two layers of encapsulation material 6a and 6b on either side of the assembly 4 of photovoltaic cells 5.

[0116] The intermediate layer 9 enables the bonding of the first layer 3 on the upper layer of encapsulation material 6a.

[0117] The intermediate layer 9 is for example constituted of a standard encapsulant used in the photovoltaics field, such as the copolymer of ethylene vinyl acetate (EVA), a polyolefin, silicone, thermoplastic polyurethane, polyvinyl butyral, among others. It may further be constituted of a liquid resin of acrylic, silicone or polyurethane type, single component or two component, cross-linkable through heat or photochemically. It may also be constituted of a pressure sensitive adhesive (PSA).

[0118] In this example, the intermediate layer 9 is constituted of a thermoplastic film, namely the thermoplastic polyurethane also known by the acronym TPU, such the TPU of Dureflex A4700 type sold by the firm Bayer or PX1001 sold by the firm American Polyfilm, of thickness equal to around 380 m.

[0119] The intermediate layer 9 makes it possible to fulfil two main functions. On the one hand, it enables the adhesion of the first layer 3 on the upper layer of encapsulation material 6a for the case where the two layers are not chemically compatible. On the other hand, it makes it possible to create within the photovoltaic module 1 a cushioning layer of a certain suppleness making it possible to improve the resistance of the module 1 to impacts and mechanical loads.

[0120] Furthermore, the photovoltaic structure assembly 10 in accordance with the invention represented in FIG. 1 also comprises a circulable zone 2. The circulable zone 2 may be of variable rigidity. In this example, it corresponds quite particularly to a road type asphalt surface.

[0121] In order to enable the bonding of the photovoltaic module 1 on the circulable zone 2, the assembly 10 also comprises a fixation layer 12. Said fixation layer 12 is constituted by a bituminous adhesive enabling the module 1 to be made to adhere to the roadway or route. In this example, it is a bitumen of ColFlex N type sold by the firm Colas, with an incorporation rate of 1 kg/m.sup.2. The use of a bituminous adhesive 12 associated with a rear face 7 of the module 1 made of a composite material may make it possible to reinforce the rear face 7 so as to avoid the risk of indentation of the photovoltaic cells 5 subjected to the passage of pedestrians and/or vehicles on a rough roadway 2. The bituminous adhesive 12 thus plays the role of a protective binder filling the interface between the roadway 2 and the rear face 7 of the module 1.

[0122] Moreover, although not represented in FIG. 1, the photovoltaic structure assembly 10 also comprises a covering layer applied to the first layer 3, intended to facilitate the circulation of pedestrians and/or vehicles.

[0123] The covering layer is non-opaque and has 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 PSV.sub.44, or even PSV.sub.50, or instead even PSV.sub.53.

[0124] A method for producing a photovoltaic structure assembly 10 in accordance with the invention will now be described.

[0125] The method comprises a first step a) of hot rolling at a temperature of around 170 C. and under vacuum (pressure less than or equal to 10 mbars) of the constituent layers 6a, 4, 6b, 11 and 7 of the photovoltaic module 1 apart from the first layer 3 and the intermediate layer 9. This first step a) of rolling is carried out for around 15 minutes so as to obtain a laminate of encapsulated photovoltaic cells 5. The rolling parameters, such as the temperature, the time and the pressure, may nevertheless depend on the encapsulating material used.

[0126] Then, the method comprises a second step b) of hot rolling at a temperature of around 125 C. and under vacuum of the laminate obtained in the course of the first step a) with the first layer 3 forming the front face of the photovoltaic module 1 by means of the intermediate layer 9. This second step b) is carried out for a duration of around 30 minutes so as to obtain the photovoltaic module 1. Before the implementation of this second step b), the panels 8 of the first layer 3 may advantageously be treated by means of a Corona treatment equipment so as to obtain a surface energy greater than or equal to 48 dyn/cm.

[0127] These first a) and second b) rolling steps are then followed by a step c) of application of a covering layer on the first layer 3 to enable the passage of pedestrians and/or vehicles, the covering layer being as described previously. Finally, a step of fixation d) of the photovoltaic module 1 on the circulable zone 2 makes it possible to form the photovoltaic structure assembly 10. This fixation step is advantageously implemented by means of a bituminous adhesive applied between the circulable zone 2 and the module 1.

[0128] Tests have been able to be carried out with different photovoltaic modules 1, comprising from 3 to 40 photovoltaic cells 5, according to the method described above. The mechanical load resistance of these modules 1, bonded onto a road asphalt 2, with static and dynamic pressures ranging up to 500 kN/m.sup.2, has been able to be demonstrated. For example, a photovoltaic module 1, constituted of three photovoltaic cells 5, did not undergo any degradation after around 64000 applications of a pressure of 500 kN/m.sup.2.

[0129] Consequently, the photovoltaic module 1 may have an increased mechanical resistance suited to restrictive applications in terms of mechanical loads, such as of the solar roadway type, but also have a piecewise flexibility on account of the presence of a discontinuous front face 3, enabling it to take different shapes to adapt to different types of surfaces, for example uneven or of imperfect flatness. In addition, the presence of a reinforced rear face 7 may make it possible to improve the indentation resistance of this rear face 7 of the module 1, said indentation being able to result in the roughness of the support 2 on which the module 1 is applied and being able to lead to fissures of the photovoltaic cells 5 of the photovoltaic module 1.

[0130] Obviously, the invention is not limited to the example of embodiment that has just been described. Various modifications may be made thereto by those skilled in the art.

[0131] The expression comprising a should be understood as being synonymous with comprising at least one, unless specified otherwise.