阅读说明：本技术 利用光伏组装方法的聚光子模块的制造 (Fabrication of concentrator submodules using photovoltaic assembly methods ) 是由 Y·鲁约尔 A·巴博 M·博德里 C·赛拉内 C·魏克 于 2018-11-30 设计创作，主要内容包括：本发明涉及用于制造聚光光伏太阳能子模块的方法,所述聚光光伏太阳能子模块具有预定义的凹形几何形状的反射表面,其特征在于,所述方法包括在单个步骤中对多层组件进行层压,所述多层组件依次包括：结构元件,其具有反射性的第一表面和与所述第一表面相反的第二表面；光伏接收器,其位于所述结构元件的第二表面上；由透明密封材料制成的层,其覆盖所述光伏接收器；以及透明保护层,其覆盖由透明密封材料制成的层,所述透明保护层和所述由密封材料制成的层至少覆盖所述光伏接收器的整个表面；并且,在层压过程中,结构元件的反射表面通过与反模的凸表面进行接触而成型,从而获得预定义的凹形几何形状的反射表面。(The invention relates to a method for manufacturing a concentrated photovoltaic solar sub-module having a reflective surface with a predefined concave geometry, characterized in that it comprises laminating, in a single step, a multilayer assembly comprising, in succession: a structural element having a reflective first surface and a second surface opposite the first surface; a photovoltaic receiver on a second surface of the structural element; a layer made of a transparent sealing material covering the photovoltaic receiver; and a transparent protective layer covering the layer made of a transparent sealing material, the transparent protective layer and the layer made of a sealing material covering at least the entire surface of the photovoltaic receiver; and, during the lamination process, the reflective surface of the structural element is shaped by contact with the convex surface of the counter mold, so as to obtain a reflective surface of predefined concave geometry.)

1. A method for manufacturing a concentrated photovoltaic solar sub-module having a reflective surface of a predefined concave geometry, characterized in that it comprises laminating, in a single step, a multilayer assembly comprising in sequence:

-a structural element having a reflective first surface and a second surface opposite to the first surface;

-a photovoltaic receiver located on a second surface of the structural element;

-a layer made of a transparent sealing material covering the photovoltaic receiver; and

-a transparent protective layer covering the layer made of transparent sealing material; the transparent protective layer and the layer made of sealing material cover at least the entire surface of the photovoltaic receiver;

wherein, during the lamination process, the reflective surface of the structural element is shaped by contact with a convex surface of a counter mold, so that a reflective surface of a predefined concave geometry is obtained.

2. Method for manufacturing a concentrated photovoltaic solar sub-module according to the previous claim, wherein the predefined concave geometry of the reflecting surface is a paraboloid.

3. Method for manufacturing a concentrated photovoltaic solar sub-module according to any of the previous claims, wherein said lamination is a thermal vacuum lamination, the temperature of which is preferably comprised between 120 ℃ and 170 ℃.

4. The method for manufacturing a concentrated photovoltaic solar sub-module according to any of the preceding claims, wherein the sealing material is made of EVA, polyolefins, silicones, thermoplastic polyurethanes, polyvinyl butyral, functional polyolefins or ionomers.

5. The method for manufacturing a concentrated photovoltaic solar sub-module according to any of the preceding claims, wherein the transparent protective layer is made of ECTFE, FEP, PMMA, PC, ETFE, PVDF, PET, glass or CPI.

6. The method for manufacturing a concentrated photovoltaic solar sub-module according to any of the preceding claims, wherein the photovoltaic receiver is a group of photovoltaic cells on an SMI-PCB receiver interconnected by wires.

7. The method for manufacturing a concentrated photovoltaic solar sub-module according to any of claims 1 to 5, wherein the photovoltaic receiver is a set of photovoltaic cells interconnected by ribbons.

8. The method for manufacturing a concentrated photovoltaic solar sub-module according to any of claims 1 to 7, wherein the photovoltaic cells are silicon cells.

9. The method for manufacturing a concentrated photovoltaic solar sub-module according to any of claims 1 to 7, wherein the photovoltaic cell is a multijunction cell.

10. Method for manufacturing a concentrated photovoltaic solar sub-module according to any of the previous claims, wherein the structural element is formed by a core surrounded by two skin layers, one of which is covered with a reflective film forming the reflective first surface of the sub-module.

11. The method for manufacturing a concentrated photovoltaic solar sub-module according to claim 10, wherein the skin is made of a pre-impregnated polymer/fiber material, the polymer being selected from polyester, epoxy or acrylic, and the fiber being selected from glass, carbon or aramid.

12. Method for manufacturing a concentrated photovoltaic solar sub-module according to any of claims 10 and 11, wherein said core is a honeycomb structure advantageously made of aluminum, aramid of Nomex type, polypropylene or polycarbonate.

13. Method for manufacturing a concentrated photovoltaic solar sub-module according to any of claims 10 and 11, wherein said core layer is a foam advantageously made of PET, PU, PVC, PEI or PMI.

14. The method for manufacturing a concentrated photovoltaic solar sub-module according to any of claims 10 to 13, wherein said reflective film is a polymer film comprising silver or aluminum deposits.

15. The method for manufacturing a concentrated photovoltaic solar sub-module according to any of claims 1 to 9, wherein said structural element comprises an aluminum mirror.

16. A concentrated photovoltaic solar sub-module having a reflective surface of a predefined concave geometry, the concentrated photovoltaic solar sub-module comprising:

-a structural element having a reflective first surface and a second surface opposite to the first surface, the structural element comprising a core layer surrounded by two skin layers, one of the two skin layers being in direct contact with a reflective layer forming the reflective first surface of the structural element and the reflective surface of the sub-module, the second skin layer forming the second surface of the structural element;

-a photovoltaic receiver in direct contact with the second surface of the structural element;

-a layer made of a transparent sealing material covering the photovoltaic receiver; and

-a transparent protective layer forming a second surface of the sub-module, the second surface being opposite the reflective surface, the transparent protective layer covering the layer of transparent sealing material.

17. A concentrating photovoltaic sub-module having a reflective surface of a predefined concave geometry, the concentrating photovoltaic sub-module comprising:

-a structural element having a reflective first surface and a second surface opposite to the first surface, the structural element comprising an aluminium mirror forming the reflective first surface of the structural element and the reflective surface of the sub-module;

-a photovoltaic receiver in direct contact with the second surface of the structural element;

-a layer made of a transparent sealing material covering the photovoltaic receiver; and

-a transparent protective layer forming a second surface of the sub-module, the second surface being opposite the reflective surface, the transparent protective layer covering the layer of transparent sealing material.

Technical Field

The present invention relates to the manufacture of elements for concentrated photovoltaic modules, and more particularly to the manufacture of elements for concentrated photovoltaic modules based on reflective linear parabolic concentrators (or mirrors). The element is referred to as a concentrated photovoltaic sub-module.

Background

Each of said submodules comprises an optical device for concentrating the light (this optical device is commonly referred to as a mirror or a concentrator) and a photovoltaic cell forming a photovoltaic receiver and located on the back of the mirror or concentrator opposite to the reflecting surface.

When these concentrating photovoltaic sub-modules are used, they can form a concentrating photovoltaic module, the focal line of the concentrator of a sub-module being located on the back of the concentrator of the adjacent sub-module. The photovoltaic receivers of adjacent sub-modules are located at the focal line. Thus, each mirror functions as a carrier for the photovoltaic receiver in addition to functioning as a concentrator. Thus, a concentrated photovoltaic module is an assembly of a plurality of substantially identical elements (called sub-modules).

The concentrators or mirrors of these concentrating solar submodules have a reflecting surface consisting of a mirror, and a back surface to which one or a group of photovoltaic cells is fixed (see document US 1993/5180441). The parabolic shape of the module enables the rays to be concentrated. Light striking the first sub-module is reflected by the reflective surface, thereby concentrating the light onto the photovoltaic cells of a second sub-module located adjacent to the first module.

The reflecting surface may be composed of a metal layer having high reflectivity covered with a protective film, or a metal layer adhered to a substrate including an organic composite material (see document US 1994/5344496). A mesh of high thermal conductivity material may also be added to the back of the reflective surface to improve heat dissipation from the sub-module. The manufacture of the sub-modules is very complicated because many steps are required, such as forming and polishing the reflective surface or treating the surface. It is also desirable to provide a step of bonding the photovoltaic cell to the mirror.

It is also possible to manufacture a concentrated photovoltaic submodule of parabolic shape (see document US 2007/0256726) in which the light is not concentrated at the focal point of a mirror, but at the focal point of a composite solid element consisting of a plurality of mirrors. In this document, the photovoltaic cell is located at the front surface of the concentrator. To avoid the formation of air bubbles between the various components of the sub-module, multiple vacuum lamination is performed to integrate the optics, photovoltaic cells and wiring. Vacuum lamination can thus use little or no adhesive to ensure better attachment of the optics, cells, or wires to their respective carriers. Since these different laminations form a planar composite structure, there is another manufacturing step in which the reflector is affixed to a convex or concave surface to create a parabolic shape that is used to focus the light onto the focal point of the solid optical element.

Document US 2004/0118395 proposes a solar concentrator of parabolic shape comprising a honeycomb structure surrounded by two skins. Such a honeycomb structure enables a lightweight concentrator to be obtained, which is able to support a thin mirror or a thin reflective surface and which has good mechanical strength. However, the element does not comprise a photovoltaic cell, since the element is intended to heat a fluid. In addition, the element is manufactured in a plurality of steps, specifically: the reflective surface is cold deformed, the mirror is secured to one of the two skin layers with an adhesive, and the surfaces of the skin layers and mirror are treated.

Disclosure of Invention

The present invention aims to remedy the above-mentioned drawbacks of the prior art; more specifically, the present invention aims to provide a method for manufacturing a concentrated photovoltaic sub-module comprising only a single step.

One subject of the present invention is therefore a method for manufacturing a concentrated photovoltaic solar sub-module having a reflective surface with a predefined concave geometry, characterized in that it comprises the lamination, in a single step, of a multilayer assembly comprising, in sequence: a structural element having a reflective first surface and a second surface opposite the first surface; a photovoltaic receiver on a second surface of the structural element; a layer made of a transparent sealing material covering the photovoltaic receiver; and a transparent protective layer covering the layer made of transparent encapsulant, the transparent protective layer and the layer made of encapsulant covering at least the entire surface of the photovoltaic receiver, wherein, during lamination, the reflective surface of the structural element is shaped by contact with a counter-molded convex surface, so as to obtain a reflective surface of predefined concave geometry.

According to a particular embodiment of the invention:

the predefined concave geometry of the reflecting surface may be a paraboloid;

-said lamination may be thermal vacuum lamination, the temperature of which is preferably comprised between 120 ℃ and 170 ℃;

the sealing material may be made of EVA, polyolefins, silicone, thermoplastic polyurethane, polyvinyl butyral, functional polyolefins or ionomers;

the transparent protective layer may be made of ECTFE, FEP, PMMA, PC, ETFE, PVDF, PET, glass or CPI;

the photovoltaic receiver may be a group of photovoltaic cells interconnected by wires on a SMI-PCB receiver, or may be a group of photovoltaic cells interconnected by strips, the photovoltaic cells being silicon cells or multi-junction cells;

the structural element may be formed by a core surrounded by two skins, one of which is covered with a reflective film forming the reflective first surface of the submodule, in which case the skins may be made of a pre-impregnated polymer/fibre material, the polymer being selected from polyester, epoxy or acrylic, and the fibres being selected from glass, carbon or aramid, the core may be a honeycomb structure advantageously made of aluminium, aramid of Nomex type, polypropylene or polycarbonate, or the core may be a foam material advantageously made of PET, PU, PVC, PEI or PMI;

the reflective film may be a polymer film comprising a silver or aluminum deposit; and is

The structural element may comprise an aluminium mirror.

Another subject of the invention is a concentrated photovoltaic solar submodule having a reflective surface with a predefined concave geometry, comprising: a structural element having a reflective first surface and a second surface opposite the first surface, the structural element comprising a core layer surrounded by two skin layers, one of the two skin layers being in direct contact with a reflective layer forming the reflective first surface of the structural element and the reflective surface of the sub-module, the second skin layer forming the second surface of the structural element; a photovoltaic receiver in direct contact with the second surface of the structural element; a layer made of a transparent sealing material covering the photovoltaic receiver; and a transparent protective layer forming a second surface of the sub-module, the second surface being opposite the reflective surface, the transparent protective layer covering the layer of transparent sealing material.

Another subject of the invention is a concentrating photovoltaic sub-module having a reflective surface with a predefined concave geometry, the sub-module comprising: a structural element having a reflective first surface and a second surface opposite the first surface, the structural element comprising an aluminum mirror forming the reflective first surface of the structural element and the reflective surface of the sub-module; a photovoltaic receiver in direct contact with the second surface of the structural element; a layer made of a transparent sealing material covering the photovoltaic receiver; and a transparent protective layer forming a second surface of the sub-module, the second surface being opposite the reflective surface, the transparent protective layer covering the layer of transparent sealing material.

Drawings

Other features, details and advantages of the invention will become apparent from a reading of the description provided with reference to the accompanying drawings, which are given by way of example and respectively show:

fig. 1a shows a cross-sectional view of a module consisting of two sub-modules, illustrating the operation of a concentrated photovoltaic module;

FIG. 1b shows the characteristic dimensions of a concentrated photovoltaic module;

fig. 2 shows a schematic diagram of a method for manufacturing a concentrated photovoltaic sub-module according to an embodiment of the invention.

The elements shown in the figures are not drawn to scale and so the scale does not represent reality.

Detailed Description

Lamination is the step of applying pressure to two or more layers of hot material to bond and compress them. The pressure and temperature of this step depend on the materials used. The lamination here allows the concentrator to be shaped by applying a reverse mold.

Fig. 1a shows a cross-sectional view of two concentrating photovoltaic sub-modules, illustrating the operation of the concentrating photovoltaic module. Although only two sub-modules M1 and M2 are shown, the operations described below may be applied to multiple sub-modules. The light ray RL illuminates the first reflective surface FR of the first submodule M1. The reflecting surface FR is typically constituted by a parabolic cylindrical mirror. The parabolic shape of the mirror of sub-module M1 enables ray RL to converge at the focal point of the mirror, the location of which is precisely calculated to enable the photovoltaic receiver R to be located at the focal point. This position also corresponds to a certain point on the second surface FA of the second submodule M2. ParaboloidThe mirror has thermal, structural and optical functions. In particular, in addition to concentrating light to one point, the parabolic mirror is also able to dissipate heat so that the receiver R is at the highest temperature T_maxAnd the lowest temperature T is at the lower part of the sub-module_minThe receiver R is located at the upper part of the sub-module. The heat dissipation is indicated by arrows T in the figure_maxIs connected to T_minThe arrows of (A) indicate the temperature gradient along the submodule (US 1993/5180441). To be able to manufacture a system comprising a plurality of submodules, the second surface FA of submodule M1 may also carry a photovoltaic receiver, and the surface FR of submodule M2 may be reflective.

Figure 1b shows the characteristic dimensions of the concentrated photovoltaic module. The sub-module is given a shape of a section of a paraboloid with a focal length f. The width of the development of the paraboloid of the section is L_mir. The distance between two sub-modules is L_ouv. The length of the sub-module is l_mirThickness of the condenser is e_mirThe thickness of the submodule is e.

Fig. 2 shows a schematic diagram of a method for manufacturing a concentrated photovoltaic sub-module according to an embodiment of the invention. The transparent layer FAV covers a transparent seal E covering the photovoltaic receiver R, the structural elements being located on a counter-mold CF in the lower chamber CI of a laminator, more particularly a laminator such as used in the field of manufacturing conventional planar photovoltaic modules.

The structural element has a reflective surface and in particular comprises a core layer RD, also called reinforcement material, which is surrounded by two skin layers P, one of which is covered by a reflective film F.

The transparent layer FAV and the seal E cover at least the entire surface of the receiver R, which is located between the structural element and the seal E.

The area of the structural elements and the reflective film R is the same as the area of the desired sub-module.

The lower chamber CI and the upper chamber CS of the laminator are evacuated by a vacuum pump PV.

Denoted (FAV, E, R, P, RD, P, F), the assembly consisting of transparent layer FAV, transparent encapsulant E, photovoltaic receiver R, skin layer P, core layer RD and reflective film F is planar and is preferably hot laminated under vacuum and shaped using reverse mold CF.

In the lamination step, the counter-mould CF enables to define a concave parabolic shape of the reflective surface of the sub-module. The inverse CF thus has a surface that will be in direct contact with the reflective surface of the structural element during the lamination step. The surface has a predefined geometrical shape corresponding to the shape that the reflective surface of the structural element is intended to obtain. The reverse mould CF may be made of metal or composite material and covered with a non-stick layer (made of teflon for example). The material of the reverse-mode CF is selected to be a heat conductor and to have high mechanical strength at the lamination temperature.

The temperature, pressure conditions and duration of the lamination step are selected by the skilled person depending on the materials to be laminated. For example, the lamination step may last for at least 15 minutes, the temperature of lamination advantageously being comprised between 120 ℃ and 170 ℃, and the lamination pressure may be about 1000mbar (10)⁵Pa)。

The thickness of the assembly is preferably less than 10mm in order to maintain and ensure an optimal parabolic shape of the assembly. The thickness may also be limited by the effective height of the laminator and the counter mold CF. During the lamination process, the counter-mold CF and the components (FAV, E, R, P, RD, P, F) are for example on a hot plate PC and a uniform vertical load is gradually applied from above by means of the film M that fully conforms to its shape. During lamination, it is necessary to cross-link seal E sufficiently and to bake correctly the various elements making up the module, which are located further away or closer to the hot plate PC. For this purpose, the thermal lamination procedure is optimized in terms of temperature, pressure and duration, depending on the materials used.

According to one embodiment of the invention, the skin layer P is made of a pre-impregnated polymer/fibre material, which enables adhesion of the reflective film F to the core layer RD to be obtained. The thickness of the prepreg is less than 200 μm and the percentage of resin is comprised between 40% and 55%. The polymer is selected from polyester, epoxy or acrylic and the fibres are selected from glass, carbon or aramid.

According to another embodiment of the invention, the core layer RD is a honeycomb structure made of aramid, polypropylene, polycarbonate or aluminium of the Nomex type.

According to another embodiment of the invention, the core layer RD is a foam made of PET (polyethylene terephthalate), PU (polyurethane), PVC (polyvinyl chloride), PEI (polyetherimide) or PMI (polymethylene imine).

According to another embodiment of the invention, the transparent sealing element E has a thickness of less than 500 μm and can be made of a crosslinked elastomer such as EVA (ethyl vinyl acetate), or of a thermoplastic elastomer or an IONOMER thermoplastic copolymer (IONOMER). In the case of thermoplastic elastomers, the seal E is more particularly made of polyolefin, silicone, thermoplastic PU, polyvinyl butyral or functional polyolefin.

According to another embodiment of the invention, the transparent layer FAV has a thickness of less than 200 μm and may be made of ECTFE (or HALAR, ethylene chlorotrifluoroethylene copolymer), FEP (fluorinated ethylene propylene), PMMA (polymethyl methacrylate), PC (polycarbonate), ETFE (ethylene tetrafluoroethylene), PVDF (polyvinylidene fluoride), PET, thin glass or CPI (transparent polyimide).

According to another embodiment of the invention, the reflective film F is a polymer film with aluminum deposition or with silver deposition. Ideally, the thickness of the reflective film F should be thick enough so that the optional honeycomb core layer RD is not visible through the reflective surface of the module, so as not to disrupt light collection, while ensuring that the total weight of the sub-module remains low. The thickness of the film is advantageously comprised between 200 μm and 250 μm.

The choice of the material from which the assembly (FAV, E, R, P, RD, P and F) is made depends on the weight of the target submodule, the parabolic shape obtained to ensure good concentration, and the conditions of the environment of the module (earth, stratosphere or space). Therefore, the weight per unit area is 80g/m²To 300g/m²With carbon/epoxy prepregs in between, combined with an aluminium honeycomb of thickness 3mm, a light weight, much smaller (phase) than conventional modules can be produced30% difference) robust sub-modules.

According to another embodiment of the invention, the photovoltaic receiver R consists of photovoltaic cells which are interconnected by wires (wire bonding) and mounted on an SMI-PCB (insulated metal substrate-printed circuit board) receiver by soldering or gluing using, for example, a conductive silver adhesive. The cells may also be interconnected by straps, which enables the use of SMI-PCB receivers to be avoided. The cell may be a silicon cell, or a multijunction cell made of III-V or II-VI semiconductor material or a multijunction cell made of a material having a silicon-based perovskite structure. The cells may also be joined to each other by welding or by gluing using, for example, a conductive silver adhesive.

The following are examples of the present invention:

the transparent layer FAV consists of a thickness of 25 μm and a weight per unit area of 54g/m²HAAR (ECTFE) or FEP;

the transparent seal E consists of a thickness of 50 μm and a weight per unit area of 45g/m²(ii) an ionomer of (a);

the photovoltaic receiver R is made up of a triple junction solar cell with a width of 10mm and a length of 10mm and a SMI-PCB receiver with a thickness of 75 μm;

the core layer RD is formed by a layer having a thickness of 3mm and a weight per unit area of 78g/m²Is surrounded by two skin layers P consisting of a weight per unit area of 110g/m²The carbon/epoxy prepreg of (a);

the reflective film F consists of a reflective film made of PET, an aluminum-containing deposit and a protective varnish, the reflective film F having a thickness of 71 μm and a weight per unit area of 105g/m²。

The assembly was placed on a parabolic shaped aluminum counter mold CF of height 28mm in the lower chamber CI (effective height 35mm) of the laminator. The temperature of the hot plate was 150 ℃. Lower chamber CI degased for 300 seconds: the lower chamber CI and the upper chamber CS are pumped out by a vacuum pump PV. Next, in a second phase of duration 600 seconds, a uniform vertical load (with film M) was gradually applied at a rate of 1400mbar/min on top of the counter-mold CF on the hotplate PC until a stable segment of 1000 mbar.

Spread width L of submodule_mirIs 180mm, length l_mir1m, and the cell width is 10 mm. The focal length f of the sub-modules is 75mm and the distance between two sub-modules is L_ouv＝150mm。

According to another subject of the invention, the structural element comprises a mirror made of aluminium having a thickness of less than 0.5 mm. The assembly consisting of transparent layer FAV, seal E, photovoltaic receiver R and aluminum mirror is laminated in a single step on counter-mold CF in the same way as described above. In this case, the total weight of the sub-modules would be slightly larger (30%). The mechanical strength of the sub-modules is low and therefore additional supports will be needed: in particular, for a sub-module of length 1m, three supports are required, whereas for a sub-module of the same size made of composite material, two supports are required. However, since the degradation of the reflective part is lower than that of the organic layer, the lifetime of the sub-module is longer.