EP4133533A1

EP4133533A1 - Photovoltaic module and method for manufacturing such a module

Info

Publication number: EP4133533A1
Application number: EP21716556.2A
Authority: EP
Inventors: Roland Einhaus; Oleksiy NICHIPORUK; Emmanuel Alves; Julien DEGOULANGE
Original assignee: Yxens SAS
Current assignee: Yxens SAS
Priority date: 2020-04-06
Filing date: 2021-04-06
Publication date: 2023-02-15
Also published as: FR3109019A1; WO2021205336A1

Abstract

A photovoltaic module comprising a plurality of photovoltaic cells each comprising at least one photovoltaic active material, the photovoltaic cells being arranged between front and rear plates or sheets, and at least one seal arranged between the plates and defining, with the front and rear plates or sheets, a sealed inner volume, the module being characterised in that the inner volume comprises a passivating gas and/or a reactive gas, pure or preferably mixed with at least one inert gas, such as nitrogen, argon or helium.

Description

PHOTOVOLTAIC MODULE AND METHOD FOR MANUFACTURING SUCH

MODULE

Technical field of the invention

The present invention relates to photovoltaic modules, and more particularly to their manufacture and encapsulation. These modules include a plurality of photovoltaic cells, which must be encapsulated to protect these cells from the environment. In particular, the present invention relates to a method of assembling the photovoltaic module which is simple and which ensures a long life of the module and of the photovoltaic cells comprising a photovoltaic active material based on perovskites.

State of the art

There are many methods of manufacturing photovoltaic modules, ready to be exposed to the sun and to be plugged into an electrical circuit capable of absorbing the electrical energy they generate.

These manufacturing methods must be simple and automatable, because the assembly of the modules from the different components (which include in particular the photovoltaic cells, the electrical connectors, the structural reinforcement and protection elements (such as a slice of glass) and the encapsulation elements) represents a significant fraction of the cost price of such a module.

These methods must also ensure a long life for the photovoltaic module, which is a significant factor in calculating the economic profitability of a photovoltaic installation. It has long been known that most photovoltaic cells degrade in contact with air, humidity or water. This degradation can be linked to the photovoltaic materials themselves, or to the electrical contacts.

Furthermore, the photovoltaic cell can include interfaces which can be intrinsically unstable; their degradation can be delayed by a judicious choice of materials in contact at the interface, or the quality of these interfaces (which depends among other things on the technique of depositing the materials, the purity of these materials, their morphology , their crystallographic structure, their atomic structure). The present invention focuses on the manufacture of a photovoltaic module from one or more photovoltaic cells. Photovoltaic modules have long been known in which the photovoltaic cell is protected on its front face by a glass plate, and on its rear face either by a sheet of polymer (for example a sheet of poly (vinyl fluoride), abbreviated PVF , which is available under the brand Tedlar ™), or by another glass plate; these complexes are then encapsulated by another polymer (such as polyolefin or poly (ethylene vinyl acetate), abbreviated EVA), which is typically used in the form of a sheet. In these structures, the photovoltaic cell is embedded in the encapsulating polymer between two glass plates or a glass plate and a polymer sheet.

Electrical conductors (typically in the form of wires or strips) are attached to the conductive tracks (usually metallic) of photovoltaic cells by soldering before encapsulation; this involves local exposure of the cell to a high temperature (around 300 ° C).

The manufacturing processes for these modules generally involve a lamination step in which the entire photovoltaic cell is exposed to a temperature high enough (typically of the order of 160 ° C) so that the softened encapsulation sheet can drown the surface. photovoltaic cell.

This process has certain well-known drawbacks. The photovoltaic cell undergoes high temperature treatments, which, depending on the materials used for the photovoltaic layers or other active layers, can induce performance degradation. The encapsulating material can contaminate the photovoltaic cell with products that it releases by degassing; for example, poly (ethylene vinyl acetate), used for its excellent barrier properties, is capable of releasing acetic acid (especially in the presence of water molecules, and therefore in particular when the encapsulation is moisture permeable), which is a highly reactive molecule capable of oxidizing metal surfaces.

To overcome these drawbacks, a particular encapsulation method has been developed by the applicant, who markets it under the NICE ™ brand (New Industrial solar Cell Encapsulation technology); it has been described in documents FR 2 853 993, WO 2004/095586, EP 1 586 122 B1, WO 2014/079 945 and EP 2 923 385 B1 as well as in the publications “New Industrial solar Cell Encapsulation (NICE) technology for PV module fabrication at drastically reduced costs ”by R. Einhaus et al., 19th EU PVSEC 2004, p. 2371 - 2374, and “NICE Module Technology Using Industrial N-Type Solar Cells Without Front and Rear Busbars” by F. Madon et al., Presented at the 28th EU PVSEC congress (Paris) in October 2013.

In this method, the photovoltaic cells are arranged between two glass plates, inside a sealed volume delimited by said plates and a peripheral elastic sealing gasket. To achieve and maintain the assembly, said sealed volume is placed under vacuum, that is to say, a pressure lower than atmospheric pressure is established in this sealed volume.

NICE ™ technology overcomes some limitations of technologies commonly used for the manufacture of photovoltaic modules. This technology leads to bi-glass photovoltaic modules, with a front window and a rear window, and the only organic product used to achieve this complex is the seal in the form of a coil, which is typically made of poly ( isobutylene) or silicone, or a combination of these two polymers. This technology avoids the use of organic encapsulation materials in contact with the photovoltaic cells. It also avoids the use of welding technique to establish electrical contacts between electrical conductors and the conductive tracks of photovoltaic cells. In fact, the space between the two panes, delimited by the seal, forms a closed volume which, during the assembly of the module, is placed in a vacuum, for example by suction through a hollow needle which passes through the seal, as described in WO 2004/095 586, or by using a press included in a vacuum chamber, as described in EP 1 586 122 B1 and WO 2014/079 945. The module only holds together by this permanent depression (associated with the use of a deformable seal which provides the physical link between the front window and the rear window), which presses the windows against the photovoltaic cells and the electrical contacts on the conductive tracks of the photovoltaic cells. The passage of the conductors through the seal is made in such a way as to keep the internal volume sealed.

The pressure inside the module can typically be of the order of 0.7 bar; this pressure is essentially a nitrogen pressure which replaces the air to reduce the partial pressure of oxygen, a reactive element capable of degrading the materials of the photovoltaic cell or of the electrical contacts. Using tests of accelerated aging according to IEC 61215 and IEC 61730 standards, which involve thermal cycling and long-term testing in hot and humid environments, it has been shown that photovoltaic modules produced according to NICE ™ technology can have a lifespan of at least 25 years.

It appeared that despite all the qualities of the seal and despite the replacement of the air in the interior volume under negative pressure with nitrogen, there is a slight degassing of the components and the seal. This degassing is mainly due to molecules adsorbed on the surfaces which form part of the internal volume; among these molecules we find in particular oxygen, and also certain molecules, in particular organic, which migrate within the joint. This phenomenon leads to the gradual degradation of the atmosphere of the internal volume: the pressure tends to increase, the atmosphere of the volume loses its purity and becomes enriched in molecules capable of reacting with reactive surfaces or of being deposited on them.

WO 2012/072792 (Apollon Solar) describes a method for improving the NICE ™ technology described in the aforementioned documents, aiming to neutralize the oxygen which is liable to penetrate into the internal volume of the module during the life of the module. According to this approach, a material capable of capturing oxygen is deposited in said internal volume, this material being said to be "an oxygen getter". This material must have a high specific surface to be able to absorb a significant amount of oxygen.

This method is effective, at least for silicon-based materials, but has certain drawbacks. First, it introduces an additional step in the manufacturing process of photovoltaic modules; this step represents a manufacturing cost that we want to minimize. Moreover, insofar as the oxygen getter must spread over a certain surface in order to be able to effectively capture the residual oxygen, this method assumes the availability of a surface inside the module on which it is possible depositing said getter; insofar as one wishes to maximize the photovoltaic active surface within the module, this can induce constraints in the design of the modules.

The emergence of photovoltaic cells using photovoltaic materials other than silicon poses particular problems; this applies in particular to organic photovoltaic materials, metallo-organic materials and perovskite-like compounds. These materials have intrinsic advantages which make them particularly advantageous compared to crystalline silicon (monocrystalline or polycrystalline) or to heterojunctions between crystalline silicon and amorphous silicon usually used in industrially manufactured photovoltaic cells. In particular, these alternative photovoltaic materials have a very low material and manufacturing cost, and their optical gap can be easily adapted according to their chemical composition. By way of example, WO 2015/017885 (Newsouth Innovations) proposes structures of photovoltaic cells of the tandem type, comprising a first cell based on crystalline silicon and a second cell based on perovskite; on paper these cells are of enormous interest because of their high conversion efficiency.

However, it is well known that organic or metallo-organic or perovskite-based photovoltaic cells cannot withstand high temperatures, and degrade particularly quickly in the presence of oxygen and / or humidity. These problems are well documented, and various attempts have been proposed in the literature to solve them. The publication "Accelerated Lifetime Testing of Organic-Inorganic Perovskite Solar Cells Encapsulated by Polyisobutylene" by L. Shi et al. published in the journal ACS Appl. Mater. Interfaces 2017, 9, 25073 - 25081, shows that polyisobutylene is a material compatible with perovskite-based photovoltaic cells; the most durable photovoltaic modules are those obtained with a double glass structure, in which the photovoltaic cell, deposited on a transparent electrode of fluorinated doped tin oxide (abbreviated FTO) on the front glass, is glued to the rear glass using a polyisobutylene sheet, which also protects the edge of the two-glass complex. This solution is also described in patent application WO 2019/006507.

The publication "Design and understanding of encapsulated perovskite solar cells to withstand temperature cycling" by R. Cheacharoen, published in 2017 in the journal Energy & Environmental Science (doi: 10.1039 / c7ee02564e) identifies the mechanical fragility of photovoltaic layers of perovskite-type materials as an obstacle to their use, and proposes as an advantageous encapsulating polymer copolymer of ethylene with a polar vinyl (methacrylic acid) monomer, marketed under the name Surlyn ™ (Du Pont). The publication "Encapsulation of Organic and Perovskite Solar Cells: A Review" by A. Uddin et al., Published in the journal Coatings 2019, 9, 65 (doi: 10.3390 / coatings 9020065) discusses several encapsulation technologies and several organic encapsulation materials, and notes that the state of the art does not offer a satisfactory solution to these problems.

The inventors have observed that the existing NICE ™ technology does not make it possible to protect these materials in a sufficient manner either. There is a need for a photovoltaic module, and for a manufacturing process making it possible to produce it industrially, which even better protects the photovoltaic cells against oxygen, humidity, water and the products of degassing and degradation of materials. used in these modules, to allow the use of photovoltaic materials specially sensitive to humidity and oxygen, such as organic materials, metallo-organic and perovskites. The present invention provides a solution for photovoltaic materials based on perovskites.

Objects of the invention

The inventors realized that NICE ™ technology can be used to manufacture photovoltaic modules containing photovoltaic active materials especially sensitive to humidity and oxygen, such as perovskite-type materials, but on condition that it is modified. According to the invention, the problem is solved by modifying the NICE ™ technology by at least partial replacement of nitrogen (which replaces the air in the internal volume of the module, by acting as neutral or inert gas) by a passivating gas and / or an active gas. The choice of these passivating and / or active gases must be adapted to the nature of the photovoltaic active material to be protected.

A neutral gas (also called inert gas) does not react with its environment under the normal conditions in which said environment is found. This is the case with nitrogen in contact with materials and components likely to be found within a NICE ™ photovoltaic module. Argon as a noble gas is also an inert gas; it can be used in NICE ™ technology, but it is more expensive than nitrogen. Helium as a noble gas is also an inert gas; its use (possibly mixed with another inert gas, because of its high cost) has a specific advantage which will be explained below. The term “passivating gas” is understood here to mean a gas which prevents or inhibits, at least partially, the chemical degradation of at least one material which is in contact with said passivating gas.

The term “reactive gas” is understood here to mean a gas which is capable of reversing, at least partially, the chemical degradation of at least one material in contact with said reactive gas. This reactive gas cannot be a gas naturally present in the air in significant concentration, such as oxygen or water.

The method according to the invention can also be applied to manufacturing processes for photovoltaic modules which differ from NICE ™ technology.

In general, the invention can be implemented with photovoltaic modules comprising photovoltaic cells comprising one or more different photovoltaic active materials. These photovoltaic active materials can be selected in particular from the group formed by materials of perovskite type, and in particular materials of AZX ₃ type where

^■ A denotes a cation of a first type, which may be a cation of a metallic element, such as Cs ⁺ , Rb ⁺ , or Na ⁺ , or an organic cation, such as methylammonium CHs-Nf,

^■ Z denotes a cation of a second type, namely a cation of a metallic element, such as Pb ⁺⁺ , Zn ⁺⁺ , Bi ⁺⁺⁺ , Ga ⁺⁺⁺ , Sn ⁺⁺ and

^■ X denotes an anion such as h, Br, Cl,

^■ The ionic radius of the cations of the first type being greater than the ionic radius of the cations of the second type.

A first object of the invention is a photovoltaic module comprising a plurality of photovoltaic cells each comprising at least one photovoltaic active material, said photovoltaic cells being arranged between front and rear plates or sheets, and at least one gasket arranged between said plates and delimiting with said plates or sheets a sealed internal volume, said module being characterized in that said internal volume comprises a reactive gas, and possibly also a passivating gas, pure or preferably mixed with at least one inert gas, such as nitrogen or argon.

Said passivating gas is advantageously a reducing gas, preferably hydrogen. Said internal volume is typically maintained at a pressure below atmospheric pressure.

Said reactive gas is selected so as to be able to stabilize at least one of said photovoltaic active materials and / or the contact areas.

In one embodiment, said reactive gas comprises molecules comprising at least one nitrogen atom, and is preferably selected from the group formed by: ammonia, hydrazine, amines (preferably methylamine, dimethylamine , ethylamine, diethylamine, trimethylamine, triethylamine); this may be suitable in particular for certain photovoltaic active materials of the perovskite type.

In another embodiment, said reactive gas comprises molecules comprising a sulfur atom, and is preferably H ₂ S; this may be suitable in particular for certain photovoltaic active materials of the perovskite type.

In yet another embodiment, said reactive gas comprises molecules comprising an iodine atom, such as Hl or CH ₃ I.

In yet another embodiment, said reactive gas comprises molecules comprising a bromine atom, such as HBr or CH ₃ Br.

Another object of the invention is a method of manufacturing a photovoltaic module according to the invention, in which a plurality of photovoltaic cells is supplied, as well as front and rear plates or sheets and at least one seal, and one deposits at least one seal between said front and rear plates or sheets, so as to delimit an interior volume, a vacuum is formed in the interior volume, and said passivating gas and / or reactive gas is introduced into said interior volume, pure or preferably in mixture with at least one inert gas, before or after forming said depression.

Advantageously, said internal volume is swept with an inert gas before introducing said passivating and / or reactive gas or mixture.

Figures

Figures 1 to 6 illustrate different aspects of the invention. They each schematically represent a cross section through a photovoltaic module according to the invention. The double arrow represents the direction of the incidence of light in the photovoltaic module.

[Fig. 1] schematically shows a section through a photovoltaic module according to a first embodiment of the invention. [Fig. 2] shows a completed version of Figure 1 which shows the outlet connection member.

[Fig. 3] shows a first variant of the embodiment of FIG. 2.

[Fig. 4] shows a second variant of the embodiment of FIG. 2.

[Fig. 5] schematically shows a section through a photovoltaic module according to a second embodiment of the invention.

[Fig. 6] shows a variant of the embodiment of FIG. 5.

The following reference numbers are used in the figures and in the text of the description:

1 Photovoltaic module according to the invention

2 Front plate (P1)

3 Back plate (P2)

4 Sealing gasket (also called sealing gasket)

5 Interior volume

6 Photovoltaic cell

7 Internal face of the back plate 3

8 Photovoltaic cell substrate 6

9 External electrode of the photovoltaic cell 6

10 Output connection

11 Soft material for pressure contact

12 Clearance hole in the back plate 3

13 Auxiliary seal (for through hole 12)

14 Internal face of the front plate

detailed description

The invention can be applied to the manufacture of photovoltaic modules containing photovoltaic cells of different types.

The photovoltaic active material is the material which exhibits and which, within the photovoltaic cell in which it is used, exploits, the photovoltaic effect. It is therefore a material in which part of the incident light is absorbed and converted into carriers of electric charge. According to the invention, the photovoltaic material is a perovskite type material.

Said perovskite type materials include in particular AZX ₃ OÙ type materials - A denotes a cation of a first type, which may be a cation of a metallic element, such as Cs ⁺ , Rb ⁺ , or Na ⁺ , or an organic cation, such as methylammonium CH ₃ -NH ₃ ⁺ ,

- Z denotes a cation of a second type, namely a cation of a metallic element, such as Pb ⁺⁺ , Zn ⁺⁺ , Bi ⁺⁺⁺ , Ga ⁺⁺⁺ , Sn ⁺⁺ and

- X denotes an anion such as I-, Br, Cl.

The ionic radius of cations of the first type is greater than the ionic radius of cations of the second type.

An example of such a material is (CH ₃ NH ₃ ) PbBr3, knowing that exchanging bromine for iodine shifts the optical gap of the material towards a higher wavelength.

The invention can be carried out for example with photovoltaic cells with pigments and based on perovskites in the solid state. ^{As such, 2,2 ', 7,7,} -Tetrakis- (N, N-di-4-methoxyphenylamino) -9,9'- spirobifluorene (CAS number: 207739) can be used as hole transport layer. -72-8), also known under the designation "Spiro-OMeTAD". All these materials are very sensitive against oxygen, humidity; some of these materials degrade even in the presence of nitrogen, requiring another inert gas such as argon.

The phospholatically active material of the perovskite type can be used on its own (a so-called monolithic structure), or in combination with other materials and / or with photovoltaic cells using other materials. In particular, the photovoltaic cells that can be used in the method according to the invention can also be of the tandem type, that is to say comprise one or more photovoltaic cells superimposed one above the other, the second cell ( in the order of passage of the incident light) absorbing the fraction of light which was not absorbed by the first cell. For example, the second cell may be based on crystalline or amorphous silicon, and the first based on a perovskite-like material. In these tandem devices, the combination of the perovskite-based cell and the silicon-based (or other materials) cell can be in the form of mono- or heterojunction.

According to an essential characteristic of the invention, the internal volume of the photovoltaic module comprises a reactive gas, and possibly also a passivating gas. The passivating gas can be used pure or mixed with an inert gas, such as nitrogen and / or argon and / or helium. A reducing gas is preferably chosen which prevents or inhibits, at least partially, the chemical degradation of the metal surfaces with which it is in contact. Said metal surfaces are in particular the electrical contact surfaces. Said chemical degradation of metal surfaces is in particular oxidation. The passivating gas can also protect the photovoltaic material itself, knowing that in a photovoltaic module according to the NICE ™ technology, the photovoltaic active material is normally in direct contact with the atmosphere which prevails in the internal volume of the module, which is in depression with respect to the external atmospheric pressure.

The passivating gas is preferably hydrogen.

According to an embodiment of the invention derived from the NICE ™ process, which forms part of the state of the art, the internal volume of the module is filled with nitrogen; said internal volume remains in depression. The partial pressure of oxygen or water is never zero: In this process, the replacement of air by nitrogen may not be total, and moisture remains adsorbed on the internal surfaces of the components of the modulus, and molecules comprising oxygen atoms can be released (in particular by the degassing of surfaces and / or by the decomposition of materials) by the materials during the lifetime of the module. The presence of a reducing gas such as molecular hydrogen in the atmosphere of the internal volume of the module can at least partially inhibit the oxidative effect of oxygen.

According to a preferred embodiment of the invention, which is well suited for silicon-based photovoltaic cells, the internal volume is filled with an inert gas which comprises at least 0.5% hydrogen, and preferably at least. minus 1.0% hydrogen. A concentration between 1.0% and 5% is suitable.

The inventors have found that hydrogen as a passivating gas has another advantage: the permeability of the seal is greater for hydrogen than for the other gaseous species present in the internal volume (and in particular greater than that of the gasket). 'nitrogen). Thus, the module will undergo during its lifetime (typically at least 25 years) a small part of the hydrogen contained in its internal volume. This loss of hydrogen at least partially compensates for the increase in pressure in the internal volume following degassing and release of volatile molecules by the different materials. Thus, the hydrogen helps to regulate the internal pressure of the module (knowing that the mechanical integrity of the module according to the invention requires a slight depression within the internal volume).

In a typical embodiment, this depression in the internal volume of the module with respect to atmospheric pressure can reach 1000 mbar; it is typically at least 2 mbar, preferably at least 50 mbar, more preferably at least 100 mbar, and even more preferably at least 200 mbar. For example, one can use a pressure in the internal volume of about 700 mbar, which corresponds to a vacuum of about 300 mbar.

The reactive gas can be used neat or mixed with an inert gas, such as nitrogen and / or argon and / or helium. It is selected according to the photovoltaic material, and in the case of a plurality of photovoltaic materials (for example in certain tandem cells), according to the most fragile photovoltaic active material (for example the perovskite-type material in the case of tandem cells of perovskite - silicon type). In this regard, a gas is chosen which is capable of reversing, at least partially, the chemical degradation of at least one material which is in contact with said reactive gas. Said material is preferably a photovoltaic active material. For materials of perovskite type, said reactive gas can for example be H ₂ S, Hl; CH ₃ I, 1r Hl; CH ₃ Br, HBr.

This reactive gas can comprise molecules comprising at least one nitrogen atom, and in this case, preferably, it can be ammonia (NH ₃ ) or methylamine (CH ₃ -NH ₂ ). Another amine can also be used (for example dimethylamine, ethylamine, diethylamine, trimethylamine, triethylamine). Hydrazine (NH ₂ -NH ₂ ) can also be used. It is also possible to use a halogenated amine, for example a chloramine, which can be an organic or inorganic chloramine (for example: monochloramine, dichloramine, trichloramine).

The use of a reactive gas is advantageous when the photovoltaic module comprises at least one photovoltaic cell comprising a compound of perovskite type. The reactive gas, especially a gas comprising molecules comprising at least one nitrogen and / or sulfur and / or iodine and / or bromine atom, stabilizes the chemical composition of the perovskites. Different electrical connection modes can be implemented in the photovoltaic modules according to the invention. In general, two types of electrical connections must be provided in a photovoltaic module. The first type of connection is the series connection of photovoltaic cells or subsets of photovoltaic cells to obtain an array of photovoltaic cells capable of providing the desired output voltage.

In a first variant, applicable to photovoltaic cells deposited on their own substrate, these photovoltaic cells can be connected in series by copper tapes, without soldering. No welding is necessary if pressure is exerted by the two plates towards the interior volume; this pressure comes from a depression within said interior volume.

In a second variant, applicable to photovoltaic cells deposited on the internal face of one of the two plates, the electrical series connection is carried out during the deposition of the photovoltaic active material on the substrate, by isolating (for example by laser beam) islands or sub-assemblies; there is no need for external interconnections by copper tape or other conductors. The photovoltaic module according to the invention protects the photovoltaic cells and in particular the photovoltaic active material; this protection is, on the one hand, mechanical protection, and, on the other hand, protection against oxygen and humidity. Passivating gas specifically protects metal surfaces from oxidation, and reactive gas can protect photovoltaic active material from degradation.

The second type of connection leads from the array of photovoltaic cells to a conductor located outside the photovoltaic module; It is through this connection that the electrical energy produced by the photovoltaic module can be used.

As mentioned above, the invention can be applied to a method of manufacturing photovoltaic modules known as such under the trade name NICE ™.

Thus, the photovoltaic module according to the invention comprises a plurality of photovoltaic cells each comprising at least one photovoltaic active material, said photovoltaic cells being arranged between the front and rear plates or sheets, and at least one seal arranged between said plates and delimiting a volume sealed interior, maintained at a pressure lower than atmospheric pressure (this pressure being called "depression"). Said module is characterized in that said internal volume comprises a passivating gas and / or a reactive gas, pure or preferably mixed with at least one inert gas, such as nitrogen or argon.

The method of manufacturing such a photovoltaic module is characterized by the fact that said at least one seal is deposited between said front and rear plates or sheets, so as to delimit an internal volume, and the depression formed in said volume is formed. interior, by any suitable technique such as suction or pressing in a vacuum chamber, and said passivating gas or reactive gas, pure or preferably mixed with at least one inert gas, before or after having formed said depression.

Said seals are generally arranged at the periphery of the plates or sheets. They can be made of the same or different materials, and include a sealing joint and a reinforcing joint.

In one embodiment of the invention, the photovoltaic module comprises an assembly of photovoltaic cells. These photovoltaic cells, deposited on an appropriate substrate S, are placed side by side between the sheets or plates P1, P2, knowing that P1 here designates the “front” plate (exposed to the sun) and P2 designates the plate opposite P2. Preferably, P1 and P2 are glass plates. One can also replace one of these glass plates (or even both) by a plate or a sheet of suitable polymer material. Said sheet can be a rigid or semi-rigid sheet; it must be sufficiently rigid to allow the lasting presence within the photovoltaic module of an internal volume in depression. The back plate P2 can be made of a metal plate.

In another embodiment at least one of the photovoltaic cells (and preferably all the photovoltaic cells) of a module are deposited on one of the sheets or plates P1 or P2 which go into the manufacture of the photovoltaic module. In other words: one of the sheets or plates P1 or P2 acts as substrate S for at least one of the photovoltaic cells (and preferably for all the photovoltaic cells) of a module. Preferably it is the plate or sheet P1. This makes it possible to avoid the presence of an optical discontinuity between the glass and the photovoltaic cell. This embodiment is particularly advantageous in the case where the photovoltaic active material is a material of the perovskite type.

Within the photovoltaic module, the face of the plate or sheet P1 or P2 on which the photovoltaic cells are deposited is an internal face, so that said photovoltaic cell is protected by the other plate or sheet P2 or P1, and by the seal.

More generally, the photovoltaic active material can be deposited directly on the front plate P1, or directly on the rear plate P2, or on another substrate S (which can be in any suitable material, rigid, semi-rigid or flexible, and which will be sandwiched between the two plates P1, P2).

Figures 1 to 6 show some embodiments of a module according to the invention.

Figure 1 shows a photovoltaic module 1 which comprises a front plate (P1) 2 and a rear plate (P2) 3 which delimits, with the sealing joint 4, an internal volume 5 in which there is a photovoltaic cell 6 which has been deposited directly on the internal face 7 of the rear plate 3. Said internal volume 5 comprises a passivating gas and / or a reactive gas, possibly diluted in a neutral gas. In industrial reality, the photovoltaic module will include a plurality of photovoltaic cells; FIG. 1 gives a simplified representation.

During the manufacture of such a module, a back plate 3 is supplied on which the photovoltaic cell 6 has already been deposited (typically a plurality of photovoltaic cells), then the electrical contact members (not shown in this figure) are deposited on photovoltaic cells. We install the seal 4 and the front plate 2, then establish a vacuum in the interior volume 5; to rinse, it is possible to introduce an inert gas (or the passivating and / or reactive gas which will be used subsequently) and then evacuate again. Then the desired partial pressure of reactive gas and / or passivating gas is established. This method of assembling, evacuating and rinsing the photovoltaic module 1 can be done in a sealed chamber under reduced pressure (depression).

FIG. 2 specifies the embodiment of FIG. 1, insofar as it illustrates the positioning of the outlet connection member 10. The latter passes through the seal 4. It is in electrical contact with an electrode 9. fixed on the cell photovoltaic 6. The connection member 10 is typically flexible; you can use a metallic tape.

FIG. 3 shows a variant of this embodiment, in which an element 11 of flexible material establishes a contact by pressure between, on the one hand, the output connection member 10 and the electrode 9, and, of on the other hand, between said electrode 9 and the photovoltaic cell 6. If the interior volume 5 of the module 1 is in depression, it is this depression which creates the pressure force which establishes said contact. You can add an outer frame (not shown in the figures).

Figure 4 shows another variant in which the connection member 10 passes through a passage hole 12 made in the back plate 3; this passage hole is sealed by one or more auxiliary sealing joints 13a, b so as to preserve the interior volume 5 of the module 1.

FIG. 5 shows another embodiment of the invention, similar to that of FIG. 1, the only difference being that the photovoltaic cell 6 has been deposited on a substrate 8 which is not the back plate 3. During the manufacturing the module, an assembly of photovoltaic cells 6 is typically deposited on the rear plate, then the electrical contact members are deposited, and one continues as described in relation to FIG. 1.

FIG. 6 shows a variant of the embodiment illustrated in FIG. 1. A front plate (S1) 2 has been supplied here on the inner face 14 of which has previously been deposited at least one photovoltaic cell 6. The rear plate (S2 ) 3 is a metal sheet.

According to the invention, the atmosphere in the interior volume 5 of the module 1 comprises at least one reactive gas and / or at least one passivating gas. Typically, this interior volume also includes an inert gas, typically nitrogen. Said reactive gases and / or passivating gases can be introduced as a mixture with said inert gas. In a particular embodiment, said inert gas comprises helium. Helium has the highest diffusion coefficient among inert gases, including in solid materials such as the gasket. Being absent in the ambient atmosphere (i.e. external to the internal volume of the module), the helium contained in said internal volume will tend to diffuse first; this diffusion of the helium contained in a gas volume at lower pressure to a gas volume at higher pressure decreases the partial pressure of helium in the internal volume of the module, and thus contributes to maintaining the under-pressure within the interior volume.

Claims

1. Photovoltaic module comprising a plurality of photovoltaic cells each comprising at least one photovoltaic active material, selected from the group of perovskite type materials, and in particular AZX ₃ type materials where o A denotes a cation of a first type, which can be a cation of a metallic element, such as Cs ⁺ , Rb ⁺ , or Na ⁺ , or an organic cation, such as methylammonium CH ₃ -NH ₃ ⁺ , o Z denotes a cation of a second type, namely a cation of a metallic element, such as Pb ⁺⁺ , Zn ⁺⁺ , Bi ⁺⁺⁺ , Ga ⁺⁺⁺ , Sn ⁺⁺ and o X denotes an anion such as I-, Br, Cl , the ionic radius of the cations of the first type being greater than the ionic radius of the cations of the second type; said photovoltaic cells being arranged between front and rear plates or sheets, and at least one seal arranged between said plates and delimiting with said plates or sheets a sealed internal volume, said module being characterized in that said internal volume comprises a passivating gas and / or a reactive gas, pure or preferably mixed with at least one inert gas, such as nitrogen or argon.

2. Photovoltaic module according to claim 1, characterized in that said internal volume is maintained at a pressure below atmospheric pressure.

3. Photovoltaic module according to claim 1 or 2, characterized in that said passivating gas is a reducing gas, preferably hydrogen.

4. Photovoltaic module according to any one of claims 1 to 3, characterized in that said inert gas comprises helium.

5. Photovoltaic module according to any one of claims 1 to 4, characterized in that said reactive gas is selected so as to be able to stabilize at least one of said photovoltaic active materials.

6. Photovoltaic module according to any one of claims 1 to 5, characterized in that said reactive gas comprises molecules comprising at least one nitrogen atom, and is preferably selected from the group formed by: ammonia, l hydrazine, amines (preferably methylamine, dimethylamine, ethylamine, diethylamine, trimethylamine, triethylamine).

7. Photovoltaic module according to any one of claims 1 to 6, characterized in that said reactive gas comprises molecules comprising at least one sulfur atom, and is preferably H ₂ S.

8. Photovoltaic module according to any one of claims 1 to 7, characterized in that said reactive gas comprises molecules comprising at least one iodine atom, and is preferably selected from the group formed by: Hl, CH ₃ the.

9. Photovoltaic module according to any one of claims 1 to 8, characterized in that said reactive gas comprises molecules comprising at least one bromine atom, and is preferably selected from the group formed by: HBr, CHsBr.

10. Photovoltaic module according to any one of claims 1 to 9, characterized in that at least one of said photovoltaic cells is a tandem type cell, comprising a first photovoltaic cell with a first photovoltaic active material, selected from said group of perovskite-like materials, which is deposited on a second photovoltaic cell with a second photovoltaic active material, which is silicon-based.

11. A method of manufacturing a photovoltaic module according to any one of claims 2 to 10, wherein at least one seal is deposited between said front and rear plates or sheets, so as to define an internal volume, a depression is formed. into the interior volume, and said passivating gas and / or reactive gas, pure or preferably mixed with at least one inert gas, before or after having formed said depression is introduced into said interior volume.

12. The manufacturing method according to claim 11, wherein said internal volume is swept with an inert gas before introducing said passivating and / or reactive gas.

13. The manufacturing method according to claim 11, wherein said internal volume is swept with a passivating gas before introducing said reactive gas.

14. Method according to any one of claims 11 to 13, wherein said reactive gas comprises molecules selected from the group formed by: molecules comprising at least one nitrogen atom, preferably selected from the group formed by: ammonia, hydrazine, amines (preferably methylamine, dimethylamine, ethylamine, diethylamine, trimethylamine, triethylamine); o molecules comprising at least one sulfur atom, and preferably H ₂ S; o molecules comprising at least one iodine atom, and is preferably selected from the group formed by Hl and CH ₃ I; o molecules comprising at least one bromine atom, and is preferably selected from the group formed by HBr, CH ₃ Br.

15. A method according to any one of claims 11 to 14, wherein said inert gas introduced into said interior volume contains helium.