EP2735032A1

EP2735032A1 - Improving the longevity and ergonomics of hybrid solar modules

Info

Publication number: EP2735032A1
Application number: EP12745422.1A
Authority: EP
Inventors: Jérôme MOUTERDE; Laetitia Brottier
Original assignee: Solaire 2G
Current assignee: Solaire 2G
Priority date: 2011-07-19
Filing date: 2012-07-12
Publication date: 2014-05-28
Also published as: CN103814446A; US20140144485A1; JP2014524230A; FR2978299B1; FR2978299A1; WO2013010922A1

Abstract

At best, photovoltaic solar modules only convert 20 % of solar energy into electrical energy, the rest of this energy being dissipated. This heat stored in the photovoltaic module reduces efficiency, which decreases in an inversely proportional manner to the temperature of the photovoltaic module. To dissipate and recover this heat, it is common to associate the photovoltaic module with a heat exchanger which, in addition to cooling the photovoltaic module, will supply heat, for example to heat the sanitary water of a building. This assembly forms a hybrid solar module, whose main limitation is its weight and relatively short service life. The invention described in the present document solves these two problems by replacing the first layer of the hybrid solar module, which is conventionally a glass sheet, with a material which is lighter, less rigid, more transparent, and more compatible with the material from which is constructed the heat exchanger, which now provides the system with its rigidity. A method for manufacturing these hybrid solar modules is also described.

Description

Improved longevity and ergonomics of hybrid solar modules

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the field of hybrid solar systems. The invention relates more particularly to a method for improving the service life and efficiency of the system. The invention also relates to the method for assembling photovoltaic modules to heat exchangers, a cooling liquid circulating in said heat exchangers. BACKGROUND OF THE INVENTION

In a manner known per se, a hybrid solar system consists of a photovoltaic solar module associated with a thermal part, also called exchanger or absorber, responsible for cooling the photovoltaic solar module. Indeed, such a module composed of a plurality ^of photovoltaic elements electrically connected, provides ^electricity by converting ^solar energy within said photovoltaic cells. However, the conversion rate hardly exceeds 20%, the rest of the solar energy received by the system being dissipated. However, the efficiency of photovoltaic cells decreases with temperature, of ^the order of 0.4% extra degree of efficiency for the semiconductor crystalline silicon technology. It is therefore crucial to control the temperature of photovoltaic panels to ensure a constant or even improved performance. To evacuate the heat, it is common to attach to the photovoltaic module a heat exchanger including a cooling system with air circulation or liquid, allowing more to use this heat, for example for the heating of sanitary water of a building.

Conventionally, a photovoltaic solar module consists of a plurality of photovoltaic elements encapsulated in a binder, generally thermopiastic polymers. The binder is activated during ^an assembly process of the cells by heating and pressure called lamination. A rigid base of transparent material, usually glass, is integrated in the panel during the lamination process on the face facing the sun, and plays the role of rigid support of the photovoltaic module. This layer of transparent material is commonly called facial sheet, translated into English by "frontsheet". On the opposite face of the module is integrated a layer of electrically insulating and waterproof material, generally a polyvinyl fluoride film, said layer being commonly called backsheet translated into English by "backsheet".

To make a hybrid solar module, the photovoltaic module is assembled to a heat exchanger, by sticking it on the opposite side of the photovoltaic module with a special resin. This heat exchanger plays a role in cooling the photovoltaic module by air or by water, and uses the calories recovered for other applications, for example the heating of the water of a building. Thus, a hybrid solar module provides electrical energy and thermal energy

Several limitations inherent in the technology exist, the main one being the incompatibilities materials generating differential expansion cycles of the hybrid solar module, causing the accelerated aging of the resin joining the photovoltaic module to the heat exchanger. Another limitation lies in the significant weight of the hybrid solar module, which leads to an increase in installation costs and limits the development of this market to buildings with recent roofs and / or sufficiently resistant.

It is known in the state of the art a method for managing the incompatibilities materials and described in US 201 1 / 0.1 14,155 A1. It is proposed to cut the metal exchanger into subparts. The sub-parts are spaced a distance corresponding to 1% of their width, and connected to each other by means of an elastic binder. This configuration has the advantage of limiting the differential expansions and increasing the service life of the panel. The problem of the weight of the module hybrid is not resolved, however, and production costs may be increased.

It is also known in the state of the art a process increasing the life of the hybrid module despite the differential expansion cycles of the materials. The document EP 1, 873,843 teaches the possibility of applying a binder between the photovoltaic module and the heat exchanger, the binder being designed to better withstand the stresses associated with the expansion of the materials. Such a method may still generate additional cost and in no way reduces the weight of the installation.

Furthermore, it is also known in the state of the art a hybrid solar panel whose exchanger ensures, in addition to its initial cooling function photovoltaic elements. the rigidity function of the system. Patent WO20071441 13 discloses an exchanger ensuring the rigidity of the system, since it is an integral part of the frame surrounding the system. Such an exchanger however remains particularly heavy, and is not suitable for all types of roofs.

GENERAL DESCRIPTION OF THE INVENTION

The present invention therefore aims to overcome one or more of the disadvantages of the prior art, by proposing a hybrid solar module installation eliminating the differential expansion problems, and reducing the weight.

For this purpose, the invention relates to a hybrid solar module, comprising at least one photovoltaic module consisting of at least one semiconductor element converting part of the solar energy into electrical energy, one of the two faces of said module being exposed to radiation, at least one heat exchanger placed opposite the face of the photovoltaic module opposite to that exposed to radiation, in which circulates a cooling fluid for recovering the thermal energy accumulated or dissipated, characterized in that it comprises: i. A layer of transparent material capable of being subjected to mechanical deformations compatible with the deformations suffered by the materials constituting the heat exchanger and deposited on the face of the photovoltaic module receiving the radiation, said layer being bonded to the photovoltaic module by a layer of encapsulating material; ii. A layer of encapsulating material deposited on the face of the photovoltaic module opposite to that receiving the radiation to fix the heat exchanger on this opposite face of the photovoltaic module; iii. A heat exchanger at least the face in contact with the photovoltaic solar module is rigid and flat.

Thus, the hybrid solar module described has the advantage of eliminating the differential expansions responsible for the accelerated aging of the adhesives linking the different elements of said module. The replacement material of the classic glass plate is less rigid than glass, but more transparent than glass, increasing the conversion efficiency of solar energy into electrical energy. In return, the rigidity and flatness of the module is reported at least on part of the heat exchanger.

According to another particularity, the hybrid solar module is compatible with existing semiconductor or organic photovoltaic technologies.

Thus, it is possible to use photovoltaic modules derived from technologies of the different generations, the photovoltaic modules being able today to consist of: solar cells based on crystalline silicon semiconductor, thin semiconducting layers, organic solar cells. According to another feature, the layer of transparent material covering the face of the module exposed to the radiation is based on fluoropolymer, said layer of material being compatible with the lamination process.

Thus, no need to modify the production lines of photovoltaic solar panels to manufacture the invention.

According to another feature, the light transmission of the layer of material covering the face of the photovoltaic module subjected to radiation is greater than the light transmission of the glass.

Thus, the efficiency of converting solar energy into electrical energy is improved compared to the hybrid solar panels described in the prior art.

According to another feature, the heat exchanger is metallic or composite material.

Thus, in addition to ensuring the rigidity of the hybrid solar module, the good thermal conductivity of the materials used makes it possible to ensure efficient cooling of the photovoltaic module.

According to another particularity, the cooling of the photovoltaic module is ensured by the circulation of a liquid film in the heat exchanger.

Thus, this solution has the advantage of increasing the contact area between the coolant and the heat exchanger, which also reduces the flow of liquid flowing in the heat exchanger.

According to another particularity, the heat exchanger consists of a first plane sub-part in contact with the photovoltaic module, and a second sub-part cooperating with the first to form the circulation channels of the cooling fluid. Thus, the choice in the form of the second subpart of the heat exchanger only depends on the technical or geometric constraints related to the cooling circuit of which this second subpart is part. According to the prior art, there is a layer of electrical insulating material whose fineness limits its thermal resistance between the photovoltaic module and the heat exchanger.

This layer is described in the prior art as being generally a polyvinyl fluoride film, which has the property of being waterproof and of being an electrical insulator.

The hybrid solar module of the invention offers the possibility of removing this insulating layer and waterproof, reporting the function of sealing or electrical insulation on the heat exchanger.

According to another feature, the composition of the encapsulant linking the photovoltaic module to the heat exchanger is modified to also make an electrical insulator.

A further object of the invention is to provide a method of manufacturing a hybrid solar module.

For this purpose, the invention relates to a method for manufacturing a hybrid solar module comprising at least one photovoltaic module consisting of at least one semiconductor element converting part of the solar energy into electrical energy, one of the two faces said module being subjected to solar radiation, at least one heat exchanger placed opposite the face of the photovoltaic module opposite to that exposed to the radiation, in which circulates a cooling fluid for recovering thermal energy accumulated or dissipated , characterized in that the method comprises the following steps: A step of depositing an encapsulant layer on the face of a portion of the heat exchanger vis-à-vis the face of the photovoltaic module opposite to that subjected to radiation; ii A step of placing the photovoltaic elements on the encapsulant layer; iii A step of depositing an encapsulant layer on the face of the photovoltaic module subjected to radiation; iv A step of setting up a layer of transparent material vis-à-vis the face of the photovoltaic module subjected to radiation; v A lamination step of the hybrid solar module.

According to another particularity, the steps can be carried out in reverse order, first step iv, then iii, then ii and then i, followed by step v of lamination of the hybrid solar module.

According to another feature, before the introduction of the photovoltaic elements in step i, is inserted a layer of insulating material followed by the deposition of an encapsulant layer vis-à-vis the face of the photovoltaic module opposite to that subjected to radiation.

According to another feature, the method is characterized in that the encapsulation of the photovoltaic module and the assembly of said module with the heat exchanger can be performed during the same lamination step. According to another feature, a second sub-portion of the heat exchanger is assembled to the portion assembled to the photovoltaic module, following the lamination operation for assembling the hybrid solar module.

Thus, the photovoltaic module can be assembled according to a lamination method described in the prior art. Replacing the glass plate with a layer of less rigid and transparent material makes it possible to assemble at least all or part of the heat exchanger and the photovoltaic module according to the lamination process by reversing the order of the layers. Indeed, it is easier to start the operation of lamination by the layer containing a portion of the heat exchanger within the scope of the invention. It is also possible to build the entire hybrid solar module in a single lamination operation, thus avoiding additional assembly costs. Finally, it is possible to assemble the first part of the exchanger to the photovoltaic module during the lamination operation, and then to assemble the second subpart of the heat exchanger by any known means of the heat exchanger. skilled in the art, for example by gluing.

The invention, with its features and advantages, will emerge more clearly on reading the description given with reference to the accompanying drawings, in which: FIG. 1a is a sectional view of the photovoltaic solar module covered with the layer of transparent material;

FIG. 1b shows a sectional view of the hybrid solar module according to a first embodiment;

FIG. 2 represents a sectional view of a second embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF

THE INVENTION

The solar panel object of the invention is a hybrid solar module, capable of producing electrical energy and thermal energy from solar energy. It is intended to be used alone or in combination with other similar modules within an installation, so that the energy produced by said panels is exploitable, for example and without limitation for a dwelling. Conventionally, the hybrid solar module can be defined as being an assembly of a photovoltaic solar module and a heat exchanger (5).

With reference to FIG. 1a, the hybrid solar module converts a part of the received solar energy into electrical energy thanks to a module photovoltaic. Said photovoltaic module is composed of a plurality of photovoltaic elements (3), typically crystalline silicon semiconductors, thin semiconductor layers, or any other technology capable of achieving the photoelectric effect. These photovoltaic elements (3) are electrically connected in series or in parallel and are encapsulated, for example and not limited to a thermoplastic polymer, for example of ^the ethylene vinyl acetate (EVA), typically in the course of a lamination process, that is to say an assembly of the photovoltaic module by heating and pressure. During this lamination step, a film (1) of material called "frontsheet" is deposited on the face of the photovoltaic module exposed to the radiation, said film (1) being transparent, flexible, UV-resistant, based on fluoropolymer, for example and without limitation ethylene tetrafluoroethylene or ETFE. This material offers a better transmission coefficient than glass, improving the efficiency of the installation. The film (1) is also much lighter than glass, significantly decreasing the weight of the invention. The main advantage of this film (1) is its relative flexibility with respect to the glass. In response to changes in temperature, the heat exchanger (5) performs cycles of expansion and retraction, due to the nature of the materials composing it. Very weak in a material such as glass, these mechanical movements are also found in the film (1) deposited on the surface of the hybrid solar module. These mechanical properties of the film (1) make it possible to eliminate the differential expansion cycles observed in the systems of the prior art and which gave rise to premature aging of the adhesives, for example epoxy adhesives, allowing the assembly of the photovoltaic module and the heat exchanger (5).

At least 80% of the solar energy received by the hybrid solar module will be dissipated in the panel. The presence of a heat exchanger (5) placed opposite the face of the photovoltaic module opposite to that exposed to radiation, allows to recover the heat accumulated or dissipated in the photovoltaic module.

In one embodiment, the heat exchanger (5) and the photovoltaic module are assembled by means of an encapsulant (23), for example and without limitation a thermoplastic polymer, for example ethylene vinyl acetate, to the from a lamination process. Thus, the cooling of the solar hybrid module is associated with the production of exploitable thermal energy. The heat exchanger is made of metal or composite material, for example and without limitation aluminum, copper or any other metal or material that is a good thermal conductor and sufficiently rigid to ensure the cohesion of the hybrid solar module. On the other hand, in order to ensure the flatness of the hybrid solar module, the face of the heat exchanger (5) fixed with the encapsulant (23, 24) against the face of the photovoltaic module opposite to that exposed the radiation must be flat. The cooling of the photovoltaic module is provided by a cooling fluid, for example air or brine, conveyed by ventilation and / or pumping means and circulating in the heat exchanger (5) still in the same direction, from the inlet (E) to the outlet (S) of said heat exchanger (5). In one embodiment, the fluid flowing in the heat exchanger (5) may, for example, form an animated film of hydrodynamic turbulence, thus ensuring a large contact surface at the face of the photovoltaic module opposite to the face exposed to the radiation. .

In one embodiment, the heat exchanger (5) is divided into two subparts (51, 52). The first subpart (51) is flat, and is assembled against the face of the photovoltaic module opposite to that subjected to radiation. The second subpart (52) is free-form, and forms with the first (51) the circulation channels of the cooling fluid. The two subparts (51, 52) of the heat exchanger (5) can be assembled by any means known to those skilled in the art, for example to using a bonding allowing the heat exchanger (5) to be held tight and under pressure.

In one embodiment, with reference to FIG. 1b, a layer of an electrical insulating material (4) also providing a sealing function is placed between the photovoltaic module and the heat exchanger (5). This layer of material (4) may for example be a polyvinyl fluoride film, and may prevent rain or moisture from the ambient air to come into direct contact with the photovoltaic module, thus avoiding any electrical problem eg false contacts or short circuits.

In one embodiment, with reference to Figure 2, it is possible to remove the layer of material (4) sealed and electrically insulating. In this case, the sealing function is taken up by the heat exchanger (5), which covers the entire surface of the photovoltaic module. The function of electrical insulator can be carried out for example by modifying the composition of the encapsulant (24), for example by using a silicone base, or for example by adding an insulating film on the face of the heat exchanger (5) in contact with the face of the photovoltaic module opposite to that exposed to the radiation. The invention described in this document can be carried out according to a manufacturing process which will now be detailed.

In one embodiment, with reference to FIG. 1a, the photovoltaic module is obtained by encapsulation of the plurality of photovoltaic elements (3), according to a lamination method described in the prior art documents and well known in the art. the skilled person. The method remains of the same type when a transparent film of material (1) is used on the face of the photovoltaic module exposed to the radiation, in place of a glass plate.

In one embodiment, with reference to FIGS. 1b and 2, the photovoltaic module and the heat exchanger (5) are assembled at the following a second lamination step. The transparent film (1) situated on the face of the photovoltaic module exposed to the radiation makes it possible to carry out plane laminations, without gluing defects, for example and in a nonlimiting manner, avoiding the presence of air bubbles between the two materials. In one embodiment and preferably, the hybrid solar module is manufactured during the same lamination operation. In this case, the lamination operation makes it possible to assemble the plurality of photovoltaic elements (3) in an encapsulant (21, 22), depositing the film (1) on the face of the photovoltaic module exposed to the radiation, assembly of the photovoltaic module and the heat exchanger (5), a layer of insulating material (4) slidable between the face of the photovoltaic module opposite to that exposed to the radiation and the heat exchanger (5), the whole being maintained with the encapsulant (23, 24), which will be electrically neutral in the absence of said insulating layer (4). Preferably, this lamination operation is performed in a precise order. In order to avoid the presence of air bubbles between the layers of materials, it is easier to deposit the less rigid layers on the more rigid ones. Thus, the heat exchanger (5) which is the most rigid corresponds to the first deposited layer, followed by the encapsulant layer (23, 24), possibly the insulating layer (4) followed by an encapsulant layer (22) depending on the embodiment, then come the photovoltaic elements (3), the encapsulant (21) and finally the layer of transparent material (1).

In one embodiment, the method of manufacturing the hybrid solar module is realized with a heat exchanger (5) composed of two sub-parts (51, 52). The method is the same as that described above, that is to say the assembly of the plurality of photovoltaic elements (3) in an encapsulant (21, 22), the deposition of the film (1) on the face of the photovoltaic module exposed to the radiation, the assembly of the photovoltaic module and the first sub-part (51) of the heat exchanger (5), a layer of insulating material (4) that can be slid between the face of the photovoltaic module opposite to that exposed to the radiation and the heat exchanger (5), the whole being maintained with the encapsulant (23, 24), which will be electrically neutral in the absence of said insulating layer (4) . Subsequently, the second subpart (52) of the heat exchanger (5) will be assembled to the rest of the hybrid solar module against the first subpart (51) by any means known to those skilled in the art, for example a bonding for holding the heat exchanger (5) in sealing and pressure. Such a method has many advantages, in particular a greater freedom of choice in the shape of the heat exchanger (5), and a lamination operation facilitated by the absence of pointed roughness on the surface of the heat exchanger (5). ) thermal.

The present application describes various technical features and advantages with reference to the figures and / or various embodiments. Those skilled in the art will appreciate that the technical features of a given embodiment may in fact be combined with features of another embodiment unless the reverse is explicitly mentioned or it is evident that these features are incompatible. In addition, the technical features described in a given embodiment can be isolated from the other features of this mode unless the opposite is explicitly mentioned.

It should be obvious to those skilled in the art that the present invention allows embodiments in many other specific forms without departing from the scope of the invention as claimed. Therefore, the present embodiments should be considered by way of illustration, but may be modified within the scope defined by the scope of the appended claims, and the invention should not be limited to the details given above.

Claims

1. Hybrid solar module installation, comprising at least one photovoltaic module consisting of at least one semiconductor element (3) converting part of the solar energy into electrical energy, one of the two faces of said module being exposed to the radiation, at least a heat exchanger (5) placed opposite the face of the photovoltaic module opposite to that exposed to the radiation, in which circulates a cooling fluid for recovering the accumulated or dissipated thermal energy, at least the face of which contact with the photovoltaic solar module is rigid and flat, characterized in that it comprises: i. A layer (1) of transparent material capable of being subjected to mechanical deformations compatible with the deformations experienced by the materials constituting the heat exchanger (5) and deposited on the face of the photovoltaic module receiving the radiation, said layer (1) being linked to the photovoltaic module by a first layer of encapsulating material (21);

ii. A second layer of encapsulating material (23) deposited on the face of the photovoltaic module opposite to that receiving the radiation to fix the heat exchanger (5) on this opposite face of the photovoltaic module;

2. Installation according to claim 1, wherein the hybrid solar module is compatible with existing semiconductor or organic photovoltaic technologies.

3. Installation according to claim 1, wherein the transparent material layer (1) covering the face of the photovoltaic module exposed to radiation is based on fluoropolymer, said layer of material (1) being compatible with the lamination process.

4. Installation according to one of the preceding claims, wherein the light transmission of the layer of material (1) covering the face of the photovoltaic module subjected to radiation is greater than the light transmission of the glass.

5. Installation according to claim 1, wherein the heat exchanger (5) is metallic or composite material.

6. Installation according to claim 1, wherein the cooling of the photovoltaic module is ensured by the circulation of a liquid film in the heat exchanger (5).

7. Installation according to claims 1, 5 and 6, wherein the heat exchanger (5) consists of a first subpart (51) plane in contact with the photovoltaic module, and a second subpart ( 52) cooperating with the first (51) to form the circulation channels of the cooling fluid.

8. Installation according to one of claims 1 to 6, wherein the composition of the encapsulant (24) linking the photovoltaic module to the heat exchanger (5) is modified to also make an electrical insulator.

9. A method of manufacturing a hybrid solar module comprising at least one photovoltaic module consisting of at least one semiconductor element (3) converting part of the solar energy into electrical energy, one of the two faces of said module being subjected to radiation. solar, at least one heat exchanger (5) placed opposite the face of the photovoltaic module opposite to that exposed to the radiation, in which circulates a cooling fluid for recovering the thermal energy accumulated or dissipated, characterized in the process comprises the steps below; i. A step of depositing an encapsulant layer (23, 24) on at least a portion of the face of the heat exchanger (5) vis-à- screw on the face of the photovoltaic module opposite to that subjected to radiation; ii. A step of placing the photovoltaic elements (3) on the encapsulant layer (23, 24); iii. A step of depositing an encapsulant layer (21) on the face of the photovoltaic module subjected to radiation; iv. A step of placing a layer of transparent material (1) vis-à-vis the face of the photovoltaic module subjected to radiation; v. A lamination step of the hybrid solar module; the steps that can be performed in a different order, first step iii, then iv, then i and ii, followed by step v of lamination of the hybrid solar module.

10. The method of claim 9 wherein, before the introduction of the photovoltaic elements (3) in step i, is inserted a layer of insulating material (4) followed by the deposition of an encapsulant layer (22). vis-à-vis the face of the photovoltaic module opposite to that subjected to radiation.

1 1. A method according to claim 9 to 10 wherein ^the encapsulation of the photovoltaic module assembly and said module with the exchanger (5) heat can be conducted during the same lamination step.

12. The method of claim 9 wherein a second subpart (52) of the heat exchanger (5) is assembled to the portion (51) assembled to the photovoltaic module, following the lamination operation for the assembly of the hybrid solar module.