Solar module for BIPV applications

Abstract

Solar module for BIPV applications The invention relates to an advantageous solar module, for use in a building, comprising (i) a flexible polymeric front sheet; (ii) a back sheet; and (iii) a core disposed between said front sheet and said back sheet, said core comprising a plurality of solar cells encapsulated by at least an encapsulant layer and said plurality of solar cells comprising crystalline silicon solar cells; wherein said back sheet is a building substrate and has a flexural stiffness higher than 0.5 N.m2.

Description

[0001] Solar module for BIPV applications

[0002] Technical Field

[0003] The present invention is in the context of solar energy production and, in particular, in the domain of Building Integrated Photovoltaics.

[0004] In particular, the invention relates to a rigid solar module, for use in a building, notably advantageous in terms of cost, weight, versatility, aesthetics, ease of installation and durability / resistance (to impact, environment, weathering, etc.).

[0005] Prior art

[0006] Currently, solar energy is one of the leading renewable energy sources that helps support energy transition into decarbonization for a safer / greener future. The global adoption and use of photovoltaic modules as one of the renewable sources of energy is key to help such transition and achieve the goals set by countries and / or international organizations.

[0007] In particular, Building Integrated Photovoltaics (BIPV) is becoming more popular as a way to reduce carbon footprint, energy expense and independence of buildings (public or private). BIPV application focuses on durability and aesthetics and, due to its high price, is mostly present in prestigious architectural projects.

[0008] A typical BIPV module comprises a glass sheet at the backside (commonly named “back sheet” or “rear sheet”), a glass sheet at the front side (commonly named “front sheet), crystalline silicon (commonly named “c-Si”) solar cells “sandwiched” therebetween thanks to one or more thermoplastic encapsulant layers like EVA or POE.

[0009] The use of glass as front sheet (FS) material was the most obvious choice so far when addressing the requirements of providing mechanical stability, high transparency in the spectral response range of solar cells and theirprotection from the environment / weather (thereby reducing risk of breakage, dust soiling, water corrosion, cracking by impacts, etc.).

[0010] And, combining a glass front sheet with a glass back sheet (BS) in a glass(FS) / glass(BS) module is very advantageous for a BIPV utilization because of their aesthetics generating appropriate appearance when mounted on a fagade window or glass roof / canopy. This solution has therefore been much used so far in such applications.

[0011] Unfortunately, those glass / glass solar modules present serious drawbacks :

[0012] their high weight;

[0013] the mounting system on the fagade cladding needs to be reinforced or seriously adapted to cope with their weight; it limits the type of construction companies able to sell and install it;

[0014] their high cost (for the module but also its installation); need of relatively high amounts of encapsulant material, which increase their production costs and reduce their fire resistance; especially matchable only with window parts of a building. their typically higher calorific value than the substituted fagade element.

[0015] In order to address some of the above drawbacks of glass / glass modules, it exists an alternative BIPV solution using a polymeric back sheet instead of a glass back sheet, thereby providing a glass(FS) / polymer(BS) module. This indeed allows reducing the module weight and cost. Nevertheless, this solution still requires a significant adaptation of the mounting system on the building and it is also matchable only with window parts of the building. Moreover, the polymeric back sheet, at the inner side of the module once mounted on a building, cannot cope with the fire-resistant regulation rules (especially for fagade cladding) and is not a good humidity barrier. Finally, such a glass(FS) / polymer(BS) module requires generally (e.g. when glass FS is ~3mm-thick) a frame, for example a metallic frame, to increase its mechanical strengthand be installed on the building, and therefore such modules are mainly used for roofs as they are not fully satisfying aesthetically-speaking.

[0016] Next to glass(FS) / glass(BS) and glass(FS) / polymer(BS) solar modules, it is also known a specific assembly in which the PV cells are placed between a polymeric flexible front sheet and a polymeric flexible back sheet. Such solar assemblies / modules are advantageous especially for flexible technologies. They may also be attached at the back sheet side (i.e. with glue) on an additional rigid panel, thereby giving a final rigid assembly. This specific assembly may then be mounted like a traditional fagade cladding, using the building panel (e.g. glass, steel, etc.) as the additional rigid panel receiving the flexible solar module. However, with this flexible solar module starting assembly, thin film PV cells are used instead of crystalline silicon ones which would be highly susceptible to breakage and cracking before attachment / gluing to the receiving rigid panel. Unfortunately, thin film PV cells are much more expensive than crystalline silicon PV cells and, forthat reason, is not an economical solution for BIPV.

[0017] In the case of flexible assemblies, namely with flexible FS and flexible BS, it is also known to include, esp. in a thick layer of encapsulant in between the back sheet and the solar cells, glass fibers which increase a bit stiffness and impact resistance of the module. This allows to use advantageously crystalline silicon solar cells as they are better protected from cracks and impacts. Nevertheless, this solution, even if it solves some of the issues of a flexible assembly, is not completely satisfying, esp. as (i) it needs a high amount of encapsulant which notably increase its cost and reduce its fire resistance, and (ii) it is still flexible and needs to be attached / glue on a rigid panel (at the back sheet side).

[0018] Therefore, in the current global trends to transform passive fagades (or roofs) of buildings into active fagades (or roofs) through BIPV, there is clearly a need on the market for a solar module that allows overcoming the above disadvantages of the existing solutions and, in particular, that allows (i) a good architectural integration with aesthetic while having (ii) a low cost (in particular, using c-Si cells and less materials), (iii) a low weight and being (iv) easy to be mounted on a building (e.g. using systems similar to those used for fixingcorresponding non-solor building ponels / cloddings, esp. avoiding any additional mounting system). Such a solar module should also respect the standard requirements in the domain, namely regarding fire resistance, impact resistance, water corrosion resistance and dust protection of the solar cells.

[0019] Objectives of the invention

[0020] The present invention has notably the objective of overcoming the cited drawbacks of the prior art.

[0021] More precisely, an objective of the invention is to provide a solar module for BIPV applications which easily integrates aesthetically in building faqade claddings.

[0022] Another objective of the invention is to provide a solar module for BIPV applications that has a lower integration cost compared to known solutions, in particular compared to glass / glass solar modules.

[0023] Still another objective of the invention is to provide a solar module for BIPV applications that has a lower weight compared to known solutions, in particular compared to glass / glass solar modules.

[0024] Still another objective of the invention is to provide a solar module for BIPV applications showing a high impact resistance, as well as good properties to limit / avoid dust soiling and water corrosion of the solar cells.

[0025] Still another objective of the invention is to provide a solar module for BIPV applications that is easy to be mounted and fixed on a building faqade cladding or roof, in particular while using same or similar systems than those used for fixing corresponding non-solar building cladding, esp. without the need of additional mounting system and / or a frame.

[0026] Still another objective of the invention is to provide a solar module for BIPV applications that allows the use of crystalline silicon solar cells, while fulfilling standard requirements regarding impact resistance, water corrosion resistance and dust protection of the cells.Still another objective of the invention is to provide a solar module for BIPV applications that allows the use of crystalline silicon solar cells, while having a good fire resistance, esp. fulfilling the fire-resistant regulation rules for fagade claddings and roofs.

[0027] Finally, another objective of the invention is to provide a solution to the disadvantages of the prior art that is simpler and cheaper for the end user.

[0028] Description of the invention

[0029] The invention relates to a solar module, for use in a building, comprising :

[0030] a flexible polymeric front sheet;

[0031] a back sheet;

[0032] a core disposed between said front sheet and said back sheet, said core comprising a plurality of solar cells encapsulated by at least an encapsulant layer and said plurality of solar cells comprising crystalline silicon solar cells,

[0033] wherein said back sheet :

[0034] is a building substrate; and

[0035] has a flexural stiffness higher than 0.5 N.m2.

[0036] Hence, the invention is based on a novel and inventive approach. In particular, the inventors evidenced that, in a solar module lay-up, when combining a flexible polymeric front sheet and a rigid back sheet which is a building substrate (and will then act as the fagade cladding or roof in the targeted building) together with the other features of the invention, it is possible to the reach all of the above-cited objectives.

[0037] In particular, in the solar module of the invention, the rigid back sheet protects appropriately the solar cells from cracking on impact, thereby allowing the use of the cheaper C-Si cells, while the flexible polymeric front sheet protects said cells from the environment / weather (e.g., from water / gas corrosionand dust soiling). Moreover, the use of a building panel / substrate as the back sheet (aimed to play the role of the wall / cladding once the module is mounted / laminated on the building) allows :

[0038] that the weight of the solar module as well as the fixation and mounting system (at the backside) or mounting methodology are very similar to those of traditional building panels / substrates without PV, giving a very advantageous BIPV solution economically-speaking;

[0039] to value the building substrate as rigidifying element in the solar module; and

[0040] to take advantage of the building substrate as a very effective water barrier and dust infiltration at the back of the module. The positive economic aspect of the invention is further enhanced by :

[0041] the ability to use C-Si cells;

[0042] material savings due to :

[0043] o the use of one panel playing at the same time the role of back sheet for the solar module and building substrate; o avoiding any glue to laminate the module to the building wall / cladding when compared to the use of a flexible solar module (polymer / polymer); and

[0044] o avoiding any additional mounting system and / or a frame.

[0045] Next to the positive economic aspect, the invention has also a positive impact from an environmental point of view due to the above-cited material savings.

[0046] Next to that, the solar module of the invention uses a polymer front sheet that shows an external matt look once mounted with less or no glare / reflections compared with front sheet made of glass, and it allows furthermore (i) to adapt easily (e.g. compared with a glass FS) the colour of the module front side (to better match the building exterior look) and (ii) to better conforms to the building exterior texture.Finally, the solution of the invention is very advantageous as it is usable for any material used for faqade walls of buildings (glass, aluminum, steel, concrete, ceramic, etc.) as long as it addresses the required features regarding the back sheet of the invention.

[0047] The invention also relates to a process for manufacturing a solar module, comprising a step of laminating on a building substrate an assembly comprising, in order :

[0048] a flexible polymeric sheet

[0049] a core comprising a plurality of solar cells encapsulated by at least an encapsulant layer, said plurality of solar cells comprising crystalline silicon solar cells,

[0050] said building substrate being in direct contact with said at least an encapsulant layer.

[0051] Detailed description of the invention

[0052] According to the invention, the solar module is for use in a building, especially located outside and at the faqade, exterior wall and / or roof of said building. Any type of building may be considered in the context of the invention. The term “building” in the invention must be broadly defined as any enclosed or partially enclosed structure that provides shelter, protection, or space for human activities, storage, or operations. This definition then encompasses traditional structures, private and public (e.g., houses, offices, warehouses, greenhouses), as well as non-conventional structures that serve similar purposes, such as:

[0053] - prefabricated and modular units, including (metallic) containers used as storage units, mobile offices or housing;

[0054] - temporary structures; and

[0055] - mobile and / or transportable structures, such as trucks, trailers, train or motor- homes / campers.The solar module of the invention may have various sizes and shapes, appropriate to reach the objectives and fit the building where it is integrated. For example, it may be in the form of a rectangular panel, with each side having dimensions that may be from a few dozen centimeters to several meters.

[0056] According to an embodiment of the invention, the solar module is flat. The term “flat” herein relates to the related field and is fully understood by the person skilled in the art. In particular, it allows a certain degree of freedom regarding perfect flatness. For example, according to the invention, the solar module has preferably a curvature radius R of higher than 800 mm, 1000 mm, 1500 mm or even higher than 2000 mm, at any point of the surface of the solar module. Alternatively, according to an embodiment of the invention, the solar module is bent or folded, for example folded at its periphery.

[0057] According to the invention, the solar module comprises a flexible polymeric front sheet. The term “front sheet” herein relates to the related field and is fully understood by the person skilled in the art. The term “flexible” herein relates to the related field and is fully understood by the person skilled in the art.

[0058] Preferably, the front sheet has a flexural stiffness of lower than 1.0 N.m2, more preferably of lower than 0.1 N.m2. This is advantageous as the front sheet, with its flexibility, is able to better conform the shape and texture of the building substrate, thereby allowing a good lamination / adhesion.

[0059] The front sheet is advantageously transparent. Preferably, it has an average transmittance in the visible wavelength range (360 - 740 nm) of higher than 80%, more preferably, higher than 85%.

[0060] The front sheet provides protection from weathering, dust and / or moisture, and preferably ultraviolet (UV) protection to reduce or prevent degradation of the lower layers of the module due to sunlight.

[0061] Said front sheet may colored, in order for example to match aesthetically with the building substrate appearance. Said front sheet may be textured, in order for example to match aesthetically with the building substrate appearance and / or in order to maximize sunlight transmission towards solar cells.Preferably, said front sheet has a thickness between 0.1 and 3 mm. More preferably, it has a thickness lower than 1 mm, lower than 0.7 mm and even, lower than 0.5 mm.

[0062] Said front sheet may be composed of a plurality of laminated flexible polymeric layers, different or the same in nature, composition and / or thickness.

[0063] Said front sheet may be made of at least one material selected from ethylene tetrafluoroethylene (ETFE), ethylene chlorotrifluoroethylene, polyfluoroethylene, fluorinated ethylene propylene (FEP), ethylene propylene copolymer, polycarbonate, polyethyleneterephtalate (PET), fluoro-coated PET, cyclic olefin polymer (COP). It may be appreciated by one skilled in the art that other choices of material for the front sheet may be made and the specific examples mentioned herein are therefore non-limiting.

[0064] According to an advantageous embodiment, said front sheet is free of any PFAS (or “perfluoroalkyl and polyfluoroalkyl substance”). An example of such a non-PFAS material for the front sheet according to the invention contains an acryliclike polymer. A flexible front sheet sold from the company Coveme is also an appropriate example.

[0065] In another advantageous embodiment, the front sheet includes a PET (including modified PET) film in order to further improve impact resistance of the solar module of the invention. Said PET film has, for example, a thickness of 50 to 300 microns.. It can be a single layer or a multilayered material. Such PET film can also be used to improve the aesthetics of the solar module, by for instance providing a printed color / pattern directly on the film.

[0066] According to another advantageous embodiment, the front sheet includes a water barrier layer, especially when the front sheet is free of any PFAS. The Water Transmission Rate (WTR) of said water barrier layer, if any, is preferably below 0.1 gram per m2per day, as measured by the standards in industry. More advantageously, the WTR is below 0.01 gram per m2per day and most advantageously below 0.001 gram per m2per day.According to the invention, the solar module comprises a back sheet which is a building substrate. The term “back sheet” herein relates to the related field and is fully understood by the person skilled in the art. For the sake of clarity, herein, back sheet and building substrate refer to the same component and both terms may then be used interchangeably.

[0067] By “building substrate”, it is meant herein any solid substrate, preferably flat / plane, e.g. a panel, a board, a sheet, a plate, a slab, a tile, that is used in a building, especially as an external wall, a faqade cladding or a roof panel. The definition of “building” in the sense of the invention was given hereabove.

[0068] According to the invention, said back sheet has a flexural stiffness higher than 0.5 N.m2. Preferably, said back sheet has a flexural stiffness higher than 0.6 or 0.7 or 0.8 or even 0.9 N.m2. More preferably, said back sheet has a flexural stiffness higher than 1 N.m2.

[0069] Flexural stiffness, also sometimes named equally as flexural rigidity or as bending stiffness, is a parameter well known in the art of material and building. It is generally defined as a measure of a structure’s resistance while undergoing bending (when subjected to a load) or as the force couple required to bend a structure by one unit of curvature (SI unit is N.m2). It may be measured according to any known method, especially using the common and known “Three-Point Bending Test”. In the present invention, it is considered a specific definition, which is little dependent on the dimensions of the back sheet, for flexural stiffness D (in N.m2) for the bending of rectangular plates:

[0070] D = (E . t3) / (12 . (1 - n2))

[0071] whereby E = young’s modulus of the back sheet

[0072] t = thickness of the back sheet

[0073] n = Poisson’s ratio of the back sheet.

[0074] Such flexural stiffness values may be obtained without any burden by the skilled man for example through choosing the nature of the back sheet and / or adapting its thickness.Preferably, said building substrate is made of glass, metal, concrete, mortar, plastic, wood, ceramic, composite ora combination thereof.

[0075] By “composite” herein, as a building substrate, it refers, as commonly accepted in the art, to a material comprising multiple distinct layers or components, combined to create enhanced performance characteristics, such as increased strength, durability, or resistance to environmental factors.

[0076] For example, the back sheet / building substrate may be a glass sheet (from a window), a zinc panel, an aluminum panel, a steel panel, a PVC panel, a ceramic panel, a Trespa® panel, a plywood panel or a concrete slab. For example also, the back sheet / building substrate may be a composite panel composed of one or more metal sheet(s). Such a composite panel may advantageously comprise two thin aluminum sheets (1 mm thick or less) and a fire-retardant or non-combustible mineral-filled rigid core (for example, ACM for “Aluminium Composite Material”, like the product called ALUCOBOND®).

[0077] According to a preferred embodiment, said building substrate is made of glass, metal, concrete, ceramic, composite ora combination thereof.

[0078] More preferably, said building substrate is made of glass, metal excluding steel, concrete, ceramic, composite ora combination thereof.

[0079] In a very preferred embodiment, said building substrate is made of glass, concrete, ceramic, composite ora combination thereof.

[0080] In a first main embodiment of the invention, said building substrate is advantageously made of glass (namely, including glass but not limited to). According to this embodiment, the glass substrate may be any type of glass, in its color (e.g. clear glass, extra-clear glass, colored glass) and in its composition (e.g., soda-lime silicate or alumino-silicate). According to this embodiment, the glass substrate (i.e. the back sheet) has a flexural stiffness higher than 40 N.m2and, preferably, a flexural stiffness higher than 100 or even 200 N.m2. For example, a glass substrate of a thickness 3 to 12 mm, preferably 3.5 to 8 mm, is appropriate. Advantageously, in the invention, the glass substrate is a part of the external skin from said building, for instance a glass spandrel panel.In a second main embodiment of the invention, said building substrate is advantageously made of metal (namely, including metal but not limited to). For example, according to this embodiment, said building substrate is advantageously made of steel, aluminum, copper, zinc, preferably aluminum (possibly anodized aluminum). According to this embodiment, the building substrate (i.e. the back sheet) has a flexural stiffness higher than 1 N.m2. For example, if the back sheet is an aluminum sheet, a thickness of 0.5 to 4 mm, preferably of 0.9 to 2 mm is appropriate. For example also, if the back sheet is a steel sheet, a thickness of 0.5 to 6 mm, preferably of 1 to 4 mm, is appropriate. Advantageously, according to this embodiment, the building substrate made of metal may be an ACM panel. Advantageously also, according to this embodiment, the building substrate made of metal may be a roof panel or a wall, for example, from a container, a truck ora train.

[0081] According to the invention, the solar module comprises a core disposed between said front sheet and said back sheet, said core comprising :

[0082] a plurality of solar cells; and

[0083] at least an encapsulant layer, encapsulating said plurality of solar cells.

[0084] By “a plurality”, it is meant herein more than one solar cell (or, in other words, at least two solar cells).

[0085] According to the invention, said plurality of solar cells comprises crystalline silicon solar cells (also named commonly “c-Si" solar cells). It may be appreciated by one skilled in the art that any type of crystalline silicon solar cells may be used in the invention. For example, the solar cells from said plurality of solar cells are chosen from a list comprising :

[0086] monocrystalline silicon solar cells (Mono-Si);

[0087] polycrystalline silicon solar cells (Poly-Si or Multi-Si); passivated emitter and rear (PERC) solar cells (based on crystalline silicon, with an additional passivation layeron the rear side);

[0088] back contact solar cells;

[0089] n-type cells;Topcon cells;

[0090] thin-wafer solar cells (using very thin slices of crystalline silicon); heterojunction with intrinsic thin layer (HIT) solar cells (that combines crystalline silicon with an amorphous silicon thin-film layer);

[0091] tandem solar cells of the type :

[0092] o Perovskite / Crystalline silicon; and / or o CIGS / Crystalline silicon.

[0093] any combination thereof.

[0094] According to a preferred embodiment, the solar cells are chosen from monocrystalline silicon solar cells and polycrystalline silicon solar cells and combination thereof. More preferably, the solar cells are chosen from monocrystalline silicon solar cells.

[0095] According to another preferred embodiment, said plurality of solar cells consists in a plurality of crystalline silicon solar cells, preferably monocrystalline silicon solar cells.

[0096] According to the invention, said plurality of solar cells is encapsulated by at least an encapsulant layer, preferably chosen from a polyolefin elastomer (POE) layer or an ethylene vinyl acetate (EVA) layer or a combination thereof. It may be appreciated by one skilled in the art that other choices of material for the layer of encapsulant may be made and the preferred ones mentioned herein are therefore non-limiting.

[0097] Preferably, said plurality of solar cells is encapsulated by at least two encapsulant layers, preferably one on either side of said plurality of solar cells, thereby providing a front encapsulant layer and a back encapsulant layer.

[0098] According to an embodiment, the at least one encapsulant layer comprises a dispersed reinforcing material, esp. glass fibers, in order to further improve further impact resistance of the solar module of the invention, in particular regarding cells cracking. In the embodiment where the solar module comprises a front encapsulant layer and a back encapsulant layer, said dispersed reinforcing material may be either in one encapsulant layer (preferably, in the front layer) or in both layers (front and back).According to a preferred embodiment, the solar module has a total thickness of encapsulant layer(s) lower than 2 mm, preferably lower than 1.7; 1.5 mm; 1.2 mm or even lower than 1 mm. This is advantageous as a lower amount of encapsulant material (compared to glass / glass module with commonly ~3mm thickness of encapsulant) reduces the calorific value of the solar module and improves its fire resistance. Moreover, this lower amount of encapsulant material allows to improve further impact resistance of the solar module of the invention, in particular regarding cells cracking. According to this preferred embodiment, the at least an encapsulant layer is free of reinforcing material, esp. free of glass fibers.

[0099] According to another preferred embodiment, said back sheet is in direct contact with said at least an encapsulant layer. This means that no layer is present between the back sheet and the layer(s) of encapsulant. In this embodiment, advantageously, the at least an encapsulant layer helps for the lamination of the assembly front sheet / core to the back sheet / building substrate, and acts as an adhesive layer as well.

[0100] The solar module may comprise a seal covering at least a part of the edges of the solar module (also commonly named “edge seal” in the art), preferably the edges along the whole periphery of said module. This provides to the solar module, at its edges, a better moisture and chemical resistance. This embodiment is advantageous especially when using sensitive solar cells (e.g. perovskite highly sensitive to moisture and oxygen). Preferably, the solar module does not comprise any edge seal.

[0101] The edge seal in the invention may also go a bit beyond the edges of the module and cover a part of the front sheet and / or the building substrate.

[0102] The edge seal in the invention may be made from a durable and flexible material like, for example, a silicone, a polyurethane, a butyl rubber or a thermoplastic elastomer. Alternatively, in a particular embodiment, the edge seal may be made with the flexible polymeric front sheet of the invention which wraps around the edge of the solar module and even goes a bit beyond to cover a part of the building substrate.In an embodiment according to which the building substrate is in a material which is conductive, for example when the building substrate is made of metal, the solar module may advantageously comprise further an insulating layer (e.g. a PET or an EPE layer) between said back sheet / building substrate and said plurality of solar cells. In such an embodiment, preferably, the solar module comprises at least three encapsulant layers : two encapsulant layers on either side of said plurality of solar cells, providing a front and back encapsulant layers, and an additional encapsulant layer interposed between said insulating layer and said back sheet. Said additional encapsulant layer helps then for the lamination of the assembly front sheet / core / insulating layer to the back sheet / building substrate, acting as an adhesive layer. Said additional encapsulant layer is preferably chosen from a POE layer or an EVA layer or a combination thereof. It is to be noted that, according to this embodiment, the core is comprised of the plurality of solar cells, the at least three encapsulant layers and the insulating layer. In order, the core stack is : front encapsulant layer / PV cells / back encapsulant layer / insulating layer / additional encapsulant layer. This embodiment is therefore not in contradiction with the embodiment according to which the back sheet is in direct contact with the at least an encapsulant layer (herein said additional encapsulant layer).

[0103] Aesthetics of the solar module of the invention can be advantageously adapted, at a competitive price, so that it matches the aesthetics of the building material as such (without the PV elements) and that the presence of the PV cells are the less noticeable on the building by people. This is very advantageous as the architects can then integrate PV modules without negatively affecting the buildings’ look. In order to achieve the desirable aesthetics / matching, the solar module of the invention allows several options that can be implemented either independently or combined:

[0104] 1) The front sheet may include an element that diffuses light (instead of specular reflection). In that way, the surface appears with a matte or low gloss finish instead of a high gloss, very shiny surface (mirror like). This can be achieved by using hazy components including a texture most outer layer of the front sheet;2) Coloring the elements in front of the solar cells, for example coloring the encapsulant layer and / or printing colors / patterns; and / or

[0105] 3) Texturing the elements in front of the solar cells, to create a millimetric or sub-millimetric structure, either even or random.

[0106] The solar module of the invention may be manufactured according to any appropriate process.

[0107] The invention also relates to a process for manufacturing a solar module, said process comprising a step of laminating on a building substrate an assembly comprising, in order :

[0108] a flexible polymeric sheet;

[0109] a core comprising a plurality of solar cells encapsulated by at least an encapsulant layer, said plurality of solar cells comprising crystalline silicon solar cells,

[0110] wherein, at the step of laminating, the assembly is affixed to the building substrate at said core side and wherein said building substrate has a flexural stiffness higher than 0.5 N.m2.

[0111] The process of the invention is particularly advantageous to manufacture a solar module according to the invention.

[0112] Features and embodiments described above in relation with the solar module, for example for the front sheet, the back sheet, the core, the solar cells, the encapsulant layer(s), the insulating layer, are applicable to the process of the invention.

[0113] In the process of the invention, the step of laminating may be carried out by any appropriate technique to laminate a flexible foil to a substrate. For example, it may be carried out by lamination using heat and / or pressure and / or vacuum.

[0114] The invention also encompasses several advantageous embodiments for the system used to attach / affix the solar module to the targeted building. These alternative embodiments are designed to provide, incombination with the features of the module of the invention, secure attachment while also addressing the need for protection against moisture:

[0115] (1) Attachment system with insert(s):

[0116] In this embodiment, the solar module comprises an attachment system comprising at least one insert, for example in plastic or metal or a combination thereof, that is inserted / positioned through, at least partially, the solar module.

[0117] The insert according to this embodiment may be :

[0118] (a) a cylinder shape configured to fit within the thickness of the solar module through a hole, and with a hollow core designed to allow a screw to passthrough (e.g.with a screw thread). The inserts from this system are positioned where the screws used to affix the module will be placed. Preferably, the diameter of the hollow core of the insert is larger than the shaft of the screw to be used, to accommodate for thermal expansion. For such insert type, the process for manufacturing the solar comprises further:

[0119] - either, after the step of laminating, (i) a step of creating at least one hole, e.g. by drilling, through the solar module and (ii) a step of inserting an insert into said hole. The insert may be adhered (e.g. glued) or left unattached, depending on the design requirements;

[0120] - or, before the step of laminating, a step of positioning at least an insert between said back sheet and said front sheet.

[0121] Such a system may be, for example and in the case of a back sheet made of metal (esp. an ACM), a so-called “Fa-Ze-Di” system, as the one commercialized by SFS Group.

[0122] (b) a polymer material (e.g. butyl) locally replacing the layers of the core of the solar module (namely all layers between the back and the front sheets), esp. at specific locations of the module where the screws used to affix the module will be placed. The screws used with this system may feature threads along the entire shaft, though care must then be taken to avoid stressing thefront sheet. Alternatively, screws without threads may be used, allowing for thermal expansion but not ensuring electrical continuity for grounding. For such insert type, the process for manufacturing the solar module comprises further, before the step of laminating, a step of creating at least one insert of polymer material directly inside the layers of the core of the module (between the back and the front sheets).

[0123] (2) Attachment system without insert:

[0124] In this embodiment, the solar module comprises an attachment system comprising at least one hole designed to receive a screw, e.g. with a conical head, to affix the solar module, said hole being :

[0125] o either through the core and front sheet (and not the back sheet). For such embodiment, the process for manufacturing the solar module comprises further, after the step of laminating, a step of creating at least one hole, e.g. by milling, through the core and front sheet. Preferably, the diameter of the hole is larger than the shaft of the screw to be used, to accommodate for thermal expansion. With the attachment system, the screw is directly screwed inside the back sheet. This embodiment simplifies the attachment system while ensuring the structural integrity of the solar module; o or through the solar module (back sheet / core / front sheet). For such embodiment, the process for manufacturing the solar module comprises further, after the step of laminating, a step of creating at least one hole, e.g. by milling, through the solar module. Preferably, the diameter of the hole is larger than the shaft of the screw to be used, to accommodate for thermal expansion. This system may advantageously comprise further an eyelet positioned at said hole.(3) “Cassette-type” attachment system:

[0126] This embodiment is when the building substrate / back sheet is made of metal. In this embodiment, the solar module has a cassette-type shape configured to attach said solar module to a building and / or to another solar module and have at least one peripheral band that is bent or folded along one edge of the module. Preferably, the cassette-type shape has two folded peripheral bands, each along opposite edges of the solar module. “Cassette” metallic panels are already known in the art as building claddings and the skilled man in the field would be familiar and understand how to implement in shape this structure in the solar module of the invention.

[0127] The cassette-type shape according to the invention then forms an integral part of the solar module, offering a highly efficient method for both mounting and interlocking several modules to a building. This cassette-type attachment system is particularly beneficial for large-scale or modular installations, as it allows for quick and secure mounting of the solar modules of the invention. It also allows for uniformity in module positioning and alignment, making it ideal for aesthetic and functional integration on buildings.

[0128] For such “cassette-type” attachment system, the process for manufacturing the solar module comprises further, after the step of laminating, a step of shaping, e.g. through folding and at least one peripheral band of said module (namely including shaping of all layers / sheets from said module) along one edge of said module, e.g. The process may also comprise steps of cutting and / or drilling the shaped peripheral band. Preferably,

[0129] These above-described embodiments of attachment systems in the invention provide flexibility for various applications and installation conditions, with some systems being implemented before the step of laminating and others after the step of laminating, to best meet specific installation requirements.

[0130] The person skilled in the art realizes that the present invention is by no means limited to the preferred embodiments described above. It is further noted that the invention relates to all possible combinations of features, and preferred features, described herein and recited in the claims.The following examples are provided for illustrative purposes and are not intended to limit the scope of this invention.

[0131] EXAMPLES

[0132] Example 1

[0133] A solar module according to the invention was manufactured by laminating at about 150*C for 20 minutes the following assembly :

[0134] - a flexible polymeric front sheet from the company Coveme (dyMat® Clear Frontsheet Monolayer) ;

[0135] - a core with crystalline silicon solar cells encapsulated between two layers of EVA (total thickness -0.78 mm) ;

[0136] with a sheet of glass (thickness : 3.5 mm ; flexural stiffness : 248 N.m2), in contact with the core.

[0137] Example 2

[0138] A solar module according to the invention was manufactured by laminating the following assembly :

[0139] - a flexible polymeric front sheet from the company Coveme (dyMat® Clear Frontsheet Monolayer);

[0140] - a core with :

[0141] - crystalline silicon solar cells encapsulated between two layers of POE;

[0142] - a layer of EPE (thickness: 200 microns), as insulating layer; - a layer of POE (with total thickness of POE layers -1 mm); with a sheet of aluminum (thickness : 1.2 mm ; flexural stiffness : 11 N.m2), in contact with the core (from the insulating layer side).Example 3

[0143] A solar module according to the invention was manufactured by laminating the following assembly :

[0144] - a flexible polymeric front sheet from the company Coveme (dyMat® Clear Frontsheet Monolayer);

[0145] - a core with :

[0146] - crystalline silicon solar cells encapsulated between two layers of POE;

[0147] - a layer of EPE (thickness: 200 microns), as insulating layer; - a layer of POE (with total thickness of POE layers ~0.4 mm); with a sheet of Alucobond® (thickness : 3 mm ; flexural stiffness : 125 N.m2), in contact with the core (from the insulating layer side).

Claims

CLAIMS1. Solar module, for use in a building, comprising : a flexible polymeric front sheet;a back sheet;a core disposed between said front sheet and said back sheet, said core comprising a plurality of solar cells encapsulated by at least an encapsulant layer and said plurality of solar cells comprising crystalline silicon solar cells,characterized in that said back sheet :is a building substrate; andhas a flexural stiffness higher than 0.5 N.m2.

2. Solar module according to claim 1, characterized in that said back sheet is in direct contact with said at least an encapsulant layer.

3. Solar module according to any of the preceding claims, characterized in that said back sheet has a flexural stiffness higher than 1 N.m2.

4. Solar module according to any of the preceding claims, characterized in that it has a total thickness of encapsulant layer(s) lower than 2 mm.

5. Solar module according to any of the preceding claims, characterized in that said building substrate is an external fagade cladding ora roof panel.

6. Solar module according to any of the preceding claims, characterized in that said building substrate is made of glass, metal, concrete, mortar, plastic, wood, ceramic, composite ora combination thereof.

7. Solar module according to the preceding claim, characterized in that said building substrate is made of metal, preferably made of aluminum.

8. Solar module according to any of the preceding claims, characterized in that it comprises further an attachment system, said attachment system comprising :- at least one insert that is inserted through said solar module; orat least one hole designed to receive a screw, either through the core and front sheet or through the solar module.

9. Solar module according to claim 7, characterized in that it has a cassette-type shape configured to attach said solar module to a building and / or to another solar module and having at least one peripheral band that is bent or folded along one edge of said solar module.

10. Solar module according to the preceding claim, characterized in that said back sheet has a flexural stiffness higher than 40 N.m2.

11. Solar module according to any of the preceding claims, characterized in that said plurality of solar cells consists in a plurality of crystalline silicon solar cells.

12. Solar module according to any of the preceding claims, characterized in that said at least an encapsulant layer is chosen from a polyolefin elastomer layer or an ethylene vinyl acetate layer or a combination thereof.

13. Solar module according to any of the preceding claims, characterized in that said plurality of solar cells is encapsulated by at least two encapsulant layers, preferably one on either side of said plurality of solar cells.

14. Process for manufacturing a solar module according to any of claims 1 to 13, comprising a step of laminating on a building substrate an assembly comprising in order :a flexible polymeric sheeta core comprising a plurality of solar cells encapsulated by at least an encapsulant layer, said plurality of solar cells comprising crystalline silicon solar cells,wherein, at the step of laminating, said assembly is affixed to the building substrate at said core side and wherein said building substrate has a flexural stiffness higher than 0.5 N.m2.