Delamination process for a multilayer device

Abstract

Title: Delamination Process for a Multilayer Device. The invention relates to a delamination process for a multilayer device comprising several layers, at least one of these layers being an organic structure, particularly for the purpose of recycling the materials constituting these layers. The process comprises the following steps: A pre-treatment step of the multilayer device 1 consisting of perforating said at least one organic structure 10 in places, followed by a treatment step, in a reactor, of the multilayer device 1 consisting of subjecting it to at least one pressurization and depressurization cycle of a fluid 2. Figure for the abstract: Fig. 2

Description

Title of the invention: Method for delaminating a multi-layer device Technical field

[0001] The present invention relates to a method for delaminating a multi-layer device. More particularly, the invention relates to a method for delaminating a multi-layer device comprising several layers, at least one of these layers being an organic structure, in particular with a view to recycling the materials constituting these layers.

[0002] The method according to the invention applies to the delamination of any multilayer device, whatever it may be. Such multilayer devices are found, for example, in food packaging, pharmaceutical packaging, electronic devices such as computer screens, mobile phones, televisions, light-emitting diode devices, in particular organic light-emitting diodes, etc. In particular, the method according to the invention applies to the delamination of multilayer devices forming part of photovoltaic panels, whatever the technology envisaged, with a view to recycling the materials constituting them. STATE OF THE ART

[0003] There are various photovoltaic panel (PV) technologies; however, photovoltaic panels that use silicon technology - whether the silicon is crystalline, i.e. monocrystalline or polycrystalline, or amorphous - are currently the most common. It should be noted that the terms photovoltaic panel (PV panel) and photovoltaic module (PV module) are often used interchangeably. However, more specifically, we will consider here that a photovoltaic panel (PV panel) generally comprises a photovoltaic module (PV module) or photovoltaic laminate (PV laminate), possibly a frame - most often made of aluminum - which surrounds the PV module, and a junction box.There are frameless panels, in which case the term photovoltaic panel simply refers to the PV module or PV laminate with the junction box, and in this case the terms PV panel and PV module can actually be used interchangeably.

[0004] As an example, [Fig.l] represents the structure of a PV panel which may also be called a PV module, implementing silicon technology, in particular crystalline silicon. Such a PV module 1 is a multilayer assembly of polymers enabling the electrical connection of the cells to be ensured, as well as their protection throughout the life of the panel. The glass 11, on the front face, provides protection against bad weather and must ensure good optical transmission (>90%). The back face 101 (or "backsheet" according to English terminology) comprises a multi-layer assembly of polymers. It generally consists of a layer of poly(ethylene terephthalate) (or PET) adhered between two layers of fluoropolymer such as poly(vinyl fluoride) (or PVF) or poly(vinylidene fluoride) (or PVDF). Fluoropolymers have waterproof properties and prevent water from penetrating into the PV module. The front face 11 made of glass, the back face 101, as well as the electrically connected photovoltaic cells 1021, are assembled using one or more layers of encapsulant 1022 which ensures the adhesion of all the constituents. The encapsulant mainly used is poly(ethylene-co-vinyl acetate) (or EVA).

[0005] A complete process for recycling PV panels generally involves the following sequence of steps: a. Dismantling the PV panel consisting of separating the junction box and the aluminum frame from the PV module, b. Delamination of the PV module, then c. Recovery of metals contained in the cell.

[0006] The delamination processes can be mechanical, thermal or chemical or a coupling of these processes.

[0007] To implement these processes, a mechanical pre-treatment is generally carried out to reduce the treatment time linked to the delamination step where the kinetics are generally limiting, in particular for thermal or chemical treatments. These pre-treatments can be grinding (Cf. G. Granata, F. Pagnanelli, E. Moscardini, T. Havlik, L. Toro, Recycling of photovoltaic panels by physical operations, Solar Energy Materials and Solar Cells. 123 (2014) 239-248), crushing or even cutting of the PV module (Cf. V. Savvilotidou, E. Gidarakos, Pre-concentration and recovery of silver and indium from crystalline Silicon and copper indium selenide photovoltaic panels, Journal of Cleaner Production.These techniques all aim at reducing the size of the multilayer structure to be treated.

[0008] These size reduction pre-treatment processes degrade the materials constituting the PV module and limit their high added value recycling. Furthermore, they generate a loss of recoverable material due to low selectivity of these techniques. In addition, these mechanical pre-treatments contaminate the cell materials generally introduced by a mixture of material from the PV module. For example, glass fragments tend to end up in the same stream as cell fragments. Since both materials are primarily composed of silicon, recovering silicon from the cell with a high degree of purity is difficult, if not impossible, without involving complex and expensive separation methods. Finally, these processes require significant energy consumption to reduce the panel from a size of around m2 to fragments of around a few mm2.

[0009] Mechanical pre-treatment techniques are therefore not currently satisfactory for meeting the objectives of high added value recycling with limited material loss.

[0010] The delamination process described in patent FR3088579 (A1) consists of using a fluid, for example CO2, in its supercritical state, which is an intermediate state between the liquid and gaseous phases of the fluid. The fluid, and in particular CO2, in its supercritical state has in particular a capacity to diffuse very easily into the heart of porous materials (diffusion at the molecular scale) and to induce expansion by foaming of the polymer layers when it is removed abruptly.

[0011] The process used in patent FR3088579 (A1) more particularly comprises carrying out pressurization and depressurization cycles. These cycles successively cause an insertion of the fluid into the heart of the matrix of the treated material then a desorption of the fluid; the latter being accompanied by an increase in the molar volume of the fluid and, consequently, an expansion of the materials saturated with fluid. Each cycle is carried out abruptly and instantaneously whether for pressurization or for depressurization. The successive expansions and losses of expansion induce a mechanical deformation of the polymers more advanced than a simple soaking in CO2 alone, or in CO2 and co-solvent, and for shorter durations with a more favorable energy and economic impact.

[0012] Indeed, the forced and very rapid incorporation of supercritical fluid (or SC) into the polymer matrix, followed by an equally rapid withdrawal of the fluid from the polymer sheets, forms a whole likely to exacerbate the mechanical tensions between the rigid, silicon-based structure and the flexible, polymer-based structure of the PV module, due to the brutality of the conditions applied.

[0013] However, the diffusion of the SC fluid in the polymers constituting a PV module can be limiting in the case of delamination of a large PV module. For comparison, the treatable surface area for a treatment time of one hour with pulsed supercritical CO2 (or SC CO2) delamination is 8x8 mm2, compared to 10x10 mm2 for thermal treatment (Cf. A. Kuczynska-Lazewska, E. Klugmann-Radziemska, Influence of fragment size on the time and temperature of ethylene vinyl acetate lamination decomposition in the photovoltaic module recycling process, Materials. 12 (2019)) and of the order of mm2 for chemical delamination (Cf. F. Pa- gnanelli, E. Moscardini, P. Altimari, FCSM Padoan, T. Abo Atia, F. Beolchini, A. Amato, L. Toro, Solvent versus thermal treatment for glass recovery from end of life photovoltaic panels: Environmental and economic assessment, Journal of Environmental Management. 248 (2019)). In the case of the implementation of the pulsed CO2 SC delamination process, the diffusion coefficient of CO2 SC in EVA is between 0.5 and 2.0 xlO 9 m2.s 1 (Cf. A. Briand, A. Leybros, C. Audoin, JC Ruiz, F. Lamadie, A. Grandjean, CO2 absorption into a polymer within a multilayer structure: The case of poly(ethylene-co-vinyl acetate) in photovoltaic modules, The Journal of Supercritical Fluids. 179 (2022) 105380). Despite the fact that this value is in the high range of CO2 SC diffusion coefficients in solid polymers (10 12 - 108 m2.s'), the use of SC CO2 does not allow sufficient CO2 penetration for the treatment of large PV modules (> 1 m2), at least within timeframes compatible with an industrial process.

[0014] It is therefore desirable to propose a method for delaminating a multi-layer device comprising at least one organic structure which is a robust technical solution making it possible to accelerate the treatment kinetics.

[0015] It is also desirable to propose such a method which also makes it possible to avoid having to reduce the size of the PV module and thus avoid the degradation and contamination generated by the methods of reducing the size of the PV module into fragments of the order of a few mm2. SUMMARY

[0016] To achieve this objective, according to one embodiment, a method of delaminating a multilayer device comprising at least one organic structure is provided, the method comprising the following steps: a. A pre-treatment step of the multi-layer device consisting of perforating said at least one organic structure in places, then b. A step of treatment, in a reactor, of the multilayer device consisting of subjecting it to at least one cycle of pressurization and depressurization of a fluid.

[0017] The pre-treatment step thus makes it possible to create, in the organic structure, penetration paths for the fluid.

[0018] Thus, thanks to the pre-treatment step, the penetration of the fluid molecules into the organic structure is promoted during the treatment step. This makes it possible to significantly reduce the time required to carry out the treatment step, and in particular the time required to obtain a fully delaminated multilayer device, including and especially when the multilayer device has not been reduced to fragments. BRIEF DESCRIPTION OF THE FIGURES

[0019] The aims, objects, as well as the characteristics and advantages of the invention will emerge more clearly from the detailed description of an embodiment thereof which is illustrated by the following accompanying drawings in which:

[0020] [Fig.l] [Fig.l] represents an exploded view of an example of a multilayer device on which it is advantageous to implement the method according to the invention.

[0021] [Fig.2] [Fig.2] shows a sectional view through the multi-layer device of the [Fig.l] at a plurality of perforations of the organic structure of the multilayer device.

[0022] [Fig.3A] Figures 3A to 3C represent results of tests carried out on perforated PV panels with 2 cycles of pressurization and depressurization and different spacings between perforations: a spacing of 10 mm for [Fig.3A], a spacing of 7.5 mm for [Fig.3B] and a spacing of 5 mm for [Fig.3C].

[0023] [Fig.3B]

[0024] [Fig.3C]

[0025] [Fig.4] [Fig.4] illustrates a diagram of a first example of a mechanical device suitable for enabling the implementation of the pretreatment step of the multilayer device according to the method of the invention.

[0026] [Fig.5A] Figures 5A to 5B schematically represent other examples of mechanical devices suitable for enabling the implementation of the pretreatment step of the multilayer device according to the method of the invention, as well as the multilayer device during pretreatment.

[0027] [Fig.5B]

[0028] [Fig.6] [Fig.6] schematically represents an example of a clean laser device to enable the implementation of the pretreatment step of the multilayer device according to the method of the invention, as well as the multilayer device during pretreatment.

[0029] The drawings are given as examples and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily on the scale of practical applications. In particular, the thicknesses of the different layers of each multilayer device shown are not representative of reality. DETAILED DESCRIPTION

[0030] Before beginning a detailed review of embodiments of the invention, optional features which may possibly be set out below are set out. used in combination or alternatively:

[0031] According to one example, the multilayer device further comprising a glass front face, the perforation of said at least one organic structure is carried out from a rear face of the multilayer device which is opposite its front face.

[0032] According to one example, said at least one organic structure comprises a rear face based on at least one polymer and a layer comprising at least one transducer and, where appropriate, an encapsulant of said at least one transducer, the encapsulant being based on at least one polymer.

[0033] According to one example, in the multilayer device, the front face of the multilayer device is opposite the rear face of said at least one organic structure.

[0034] According to one example, at least one perforation, preferably each perforation, is made in a thickness of said at least one organic structure of the multilayer device. Preferably, at least one perforation, preferably each perforation, is made in the entire thickness of said at least one organic structure of the multilayer device.

[0035] According to one example, at least one perforation, preferably each perforation, of said at least one organic structure is in the form of a hole or a groove.

[0036] According to one example, each perforation is located at a maximum distance less than or equal to 10 mm, preferably less than or equal to 7.5 mm, and even more preferably less than or equal to 5 mm, from another perforation.

[0037] According to one example, the treatment step has a duration of less than 120 minutes, preferably less than 60 minutes and even more preferably less than 45 minutes.

[0038] According to one example, the fluid is chosen from: a. carbon dioxide CO2; b. sulfur hexafluoride; c. nitrous oxide; d. linear or branched alkanes, such as methane, propanes, butanes, and pentanes; e. cyclic alkanes; f. linear or branched alkenes, such as ethylene and propylene; g. alcohols, such as methanol, ethanol, propanols, and butanols; and h. their mixtures.

[0039] More particularly, the fluid may be chosen from carbon dioxide CO2; sulfur hexafluoride; nitrous oxide; linear or branched alkanes, preferably linear or branched alkanes of 1 to 10 carbon atoms, in particular of 1 to 5 carbon atoms, such as methane, propanes, butanes, and pentanes. ; cyclic alkanes, preferably cyclic alkanes of 3 to 10 carbon atoms; linear or branched alkenes, preferably linear or branched alkenes of 2 to 10 carbon atoms, in particular of 2 to 5 carbon atoms, such as ethylene and propylene; alcohols, preferably aliphatic alcohols of 1 to 5 carbon atoms such as methanol, ethanol, propanols, and butanols; and mixtures thereof; in particular, the fluid may be chosen from mixtures of carbon dioxide CO2 and at least one other fluid chosen from the fluids listed above.

[0040] According to one example, each pressurization and depressurization cycle comprises: a. compressing the fluid by increasing the pressure in the reactor to a pressure PI, at which the fluid is in a first physical state; then b. a decompression of the fluid by decreasing the pressure in the reactor from pressure PI to a pressure P2 at which the fluid is in a second physical state, pressure P2 being lower than pressure PI.

[0041] According to one example, said at least one cycle is preceded by bringing the multilayer device into contact, in the reactor, with the fluid at a temperature T0, such as ambient temperature, and a pressure PO, such as atmospheric pressure.

[0042] According to one example, the delamination method according to the invention is free from a step of reducing the size of the multilayer device, and in particular free from a step of grinding or crushing the multilayer device.

[0043] According to one example, at least one perforation is made using a laser.

[0044] According to one example, a plurality of perforations are made simultaneously using of a corresponding plurality of points extending from a same face of a plate.

[0045] According to one example, a plurality of perforations are made using a ridged or spiked roller.

[0046] As announced in the introduction, the present invention aims to propose a method for delaminating a multilayer device comprising at least one organic structure which is a robust technical solution making it possible to accelerate the processing kinetics. It also aims to propose such a method which also makes it possible not to have to reduce the size of the PV module and thus to avoid the degradation and contamination generated by the methods for reducing the size of the PV module into fragments of the order of a few square millimeters.

[0047] To achieve these objectives, a first immediately conceivable solution would consist of cutting a large multi-layer device into several pieces of a few square centimeters on each side. The treatment kinetics would effectively be increased, due to the fact that the contact surface between the organic structure and the fluid would be increased. However, the integrity of the possible face The glass front of the multilayer device would not be preserved, making it impossible to reuse. This first solution is still questionable in that: a. the cuts it implements may lead to degradation and / or contamination of the different layers of the multilayer device between them, and / or b. the cuts it uses cause a loss of material that it would be good to reduce, or even avoid.

[0048] The present invention proposes to achieve the objectives in a different way from the first solution envisaged above, and more particularly in a way which makes it possible to preserve the integrity of the possible glass front face of the multilayer device, so as to allow its reuse.

[0049] More particularly, and with reference to [Fig. 2], the present invention relates to a method for delaminating a multilayer device 1 comprising at least one organic structure 10, which comprises the following steps: a. A step of pre-treatment of the multilayer device 1 consisting of perforating 100 said at least one organic structure 10 in places, then, b. A step of treatment, in a reactor, of the multilayer device 1 consisting of subjecting it to at least one cycle of pressurization and depressurization of a fluid 2.

[0050] The pre-treatment step thus makes it possible to create, in the organic structure 10, penetration paths for the fluid 2.

[0051] Thus, thanks to the pre-treatment step, the penetration of the molecules of the fluid 2 into the organic structure 10 is promoted during the treatment step. This makes it possible to significantly reduce the time required to carry out the treatment step, and in particular the time required to obtain a fully delaminated multilayer device 1, including and especially when the integrity of a possible front face 11 made of glass of the multilayer device 1 is to be maintained to allow the reuse of said front face 11. This reuse is all the more desirable since the front face 11 made of glass of a PV panel 1 represents more than 75% of the weight of the panel, and since the glass is special.

[0052] Therefore, it is understood that the method according to the invention is preferably free from a step of reducing the size of the multilayer device 1, and in particular free from a step of grinding or crushing the multilayer device 1, in particular of a nature to reduce the multilayer device into fragments of the order of a few square millimeters.

[0053] The delamination method according to the present invention thus makes it possible to preserve the integrity of the multilayer device 1 with a view to its treatment, in particular according to the delamination solution disclosed in the referenced patent document FR3088579 Al.

[0054] If the method according to the invention differs from state-of-the-art methods, such as grinding or crushing, or even the solution introduced above, which degrade the structure, contaminate the materials for recycling and induce a loss of material, the pre-treatment according to the method of the invention can also have an energy advantage compared to conventional mechanical size reduction methods which are relatively energy-intensive. Furthermore, this pre-treatment, which, as we will see below, can be automated, is adapted to the means generally implemented at the industrial level.

[0055] The method according to the invention can be applied in a particularly advantageous, but non-limiting manner, to a PV panel, or more particularly to a PV module, as illustrated in [Fig.l]. More particularly, the PV module illustrated in [Fig.l] has, as a multilayer device 1, at least one so-called organic structure 10, because it is mainly composed of polymeric material, and a front face 11 made of glass. In this example, the organic structure 10 therefore comprises a rear face 101 based on at least one polymer and a layer 102 comprising at least one transducer 1021, such as a PV cell, and an encapsulant 1022 of said at least one transducer 1021, the encapsulant being based on at least one polymer. These considerations make it possible to make the link between the detailed description given in the introduction to the application of the PV module illustrated in [Fig.l] and the different terms used to describe the present invention.It is thus understood that the claimed organic structure may optionally comprise a cell, and more particularly a plurality of PV cells, encapsulated in a polymer and / or arranged in a multilayer device comprising, in addition to the PV cells, layers of organic material(s). It goes without saying that the method according to the invention is not only applicable to the type of PV modules described in the introduction to the present application, but is applicable to any other type of PV modules.

[0056] If the example of an application to the delamination of a PV module is used below to further describe the present invention, it should be recalled here that the latter is applicable to other multilayer devices, such as food packaging, pharmaceutical packaging, electronic devices such as computer screens, mobile phones, televisions, light-emitting diode devices, in particular organic light-emitting diodes, etc. It should also be noted that some of these multilayer devices comprise transducers different from those which constitute the photovoltaic cells, and that some other of these multilayer devices do not comprise a transducer.

[0057] In [Fig.2], the structure of the multilayer device illustrated in [Fig.l] is reproduced.

[0058] It can be seen in [Fig. 2] that each perforation 100 of the organic structure 10 is made from the rear face 101 of the multilayer device 1. It can also be seen that each perforation 100 is made in the thickness of the organic structure 10. More particularly, each perforation is made perpendicular to a main extension plane of the organic structure 10. It goes without saying that the method according to the invention is not limited to such orthogonality, the perforations 100 can also be inclined relative to the perpendicular to the main extension plane of the organic structure 10. Furthermore, it should be noted that the perforations 100 pass, in the example illustrated in [Fig. 2], through the layer of PV cells 1021.

[0059] Preferably, and as illustrated in [Fig. 2], each perforation is made throughout the thickness of the organic structure 10. In this way, the diffusion of the fluid 2 during the treatment of the multilayer device 1 in the reactor is favored throughout the thickness of the organic structure 10, and more particularly at the level of each of the sub-layers of the organic structure 10.

[0060] The depth of the perforations 100 is therefore an important parameter of the method according to the present invention. And the perforations 100 are preferably sized so that the fluid 2 diffuses efficiently through the organic structure 10, which, for the example illustrated in [Fig. 2], is composed, successively in order of perforated sub-layer, from bottom to top, of the rear face 101 (which is itself a PVF / PET / PVF multilayer), the EVA-based encapsulant 1022, the photovoltaic cell layer 1021, and another layer of the EVA-based encapsulant 1022. For example, for a 5 mm thick PV module 1 consisting of a 3 mm thick glass front face 11, a perforation with a depth of 2 mm allows the diffusion of the fluid 2 throughout the organic structure 10.

[0061] We will see below, when we detail different devices for perforating the organic structure 10, that the perforations can take the form of holes or grooves, or any other form, the essential thing being that each perforation contributes to promoting the diffusion of the fluid 2 in the organic structure 10 during the treatment of the multilayer device 1 in the reactor.

[0062] In [Fig.2], the parameter e is illustrated, which defines the spacing between two perforations 100 first neighboring each other.

[0063] The influence of this spacing was studied, and the results obtained are illustrated in Figures 3A to 3C. More specifically, delamination tests in CO 2 SC medium were carried out on perforated and non-perforated 200 mm x 200 mm PV panels using the 2-pulse method (130 bar for 30 minutes / 150 bar for 10 minutes) at a temperature of 75°C which is described in the patent document referenced FR308857 AL

[0064] Delamination tests carried out on non-perforated PV panels show that CO2 diffusion is very limited; it is mainly confined to the edges of the PV panel. CO2 molecules penetrate the 1022 encapsulant to a distance from the edge of only 2 to 3 mm. This therefore does not allow complete delamination of the PV panels with the 2-pulse method.

[0065] Other delamination results were obtained on perforated PV panels. These results illustrated in Figures 3A, 3B and 3C were revealed using a thermal camera. The latter makes it possible to distinguish between them the areas on which the multilayer device has been delaminated from the areas on which the multilayer device has not been delaminated, following treatment according to the 2-pulse method. The results illustrated in Figures 3A, 3B and 3C show that a spacing e between two perforations of 10 mm ([Fig.3A]) has a delamination efficiency of the front face 11 made of glass of 6.3%. This efficiency increases to 86.3% with perforations spaced 7 mm apart ([Fig.3B]) and reaches 99.3% with perforations of 5 mm ([Fig.3C])•

[0066] It emerges from the results presented above that the spacing e between two first perforations 100 adjacent to each other is another important parameter of the method according to the invention, like the depth of the perforations 100. And it is preferable that each perforation 100 is located at a maximum distance e less than or equal to 10 mm, preferably less than or equal to 7.5 mm, and even more preferably less than or equal to 5 mm, from another perforation 100.

[0067] Another important parameter of the method according to the invention consists of the characteristic size of the perforations 100, i.e. the diameter of the hole 1001 or the opening width of the groove 1002. Typically, this parameter must be chosen so that the fluid can penetrate into each perforation, preferably with ease. It can therefore depend on the nature of the fluid, and more particularly on the size of the molecules which constitute it. Typically, a perforation having a characteristic size of the order of a millimeter, for example equal to 1 mm or 2 mm, makes it possible to achieve a sufficient, or even very satisfactory, diffusion capacity of the fluids in the perforation. With regard to this characteristic size of the perforations, it is understood that this size of the perforations is preferably less than the aforementioned maximum distance e.

[0068] The effect of the pretreatment according to the present invention on the subsequent treatment step is essentially advantageous in terms of reducing the time required for the treatment step. Indeed, the duration of the treatment step can therefore be advantageously limited to 120 minutes, or even 60 minutes, or even 45 minutes. For comparison, without perforations 100, the treatment could last more than 10 days, or even more than 20 days, for a potentially less satisfactory result; for example, for a PV panel with a surface area of ​​2m2, the time estimated by calculation is more of 500 days. Note that the number of pressurization and depressurization cycles is not necessarily limited to 2.

[0069] Several devices, some purely mechanical, others physical, are envisaged, which are suitable for perforating the organic structure 10, where appropriate offering sufficient control of the perforation depth so as not to risk damaging the front glass plate 11.

[0070] Four of these devices are briefly described below with reference to Figures 4, 5A, 5B and 6. It will be noted that each of the four devices described are of a nature that can be implemented industrially.

[0071] A first perforation device, of the mechanical type, is illustrated in [Fig. 4]. This device makes it possible to perforate the PV panel 1 using metal points 31 with a diameter between 1 and 2 mm. The PV panel 1 is held between 2 plates calibrated for this purpose. The lower plate 41 or receptacle plate is equipped with an anti-lifting system 42 so that the PV panel 1, once perforated, does not remain impaled on the points 31 extending on the surface of the upper plate 32. The tips 31 or needles may have been machined from the mass or may have been transferred to the plate 32. The chemical composition of the tips 31 may be advantageously chosen so that they are harder than the material to be perforated (in particular, the silicon which makes up each PV cell 1021 is likely to be the hardest material to perforate among those which make up the organic structure 10).For example, when it is desired to perforate silicon in metallic form, the chemical composition of the tips 31 may advantageously be chosen so that the tips have a value greater than or equal to 6.5 mohs. This makes it possible to limit the wear of the tips 31 and prevents contamination of the material of the PV module 1 linked to the metallic deposition of the tips on the perforated material. To meet these criteria, the material from which the tips are made may preferably be part of the following list: diamond carbon, boron carbide (BC), silicon carbide (SiC), alumina (A12O3) or tungsten carbide (WC).

[0072] More particularly, the perforation device illustrated in [Fig. 4] uses three plates 43, 44 and 45 equipped with a mobile guided system allowing compression at the level of a perforating plate (the plate 32 equipped with the points 31) and a receptacle plate 41 supporting the PV panel 1. The guiding of the mobile plate 45 is carried out by means of a guide column 46 allowing perfect alignment between the two plates. The mobile plate 45 thus guided can be articulated by means of a single-acting hydraulic cylinder 47. An adjustment stop 48 can also make it possible to adjust the depth of the perforation of the organic structure 10 of the PV panel 1, without breaking the rear face 11 made of glass, which is in contact with the receptacle plate 4L. An anti-lifting plate 42 makes it possible to hold the PV panel 1 perforated during the descent of the mobile plate 45.

[0073] This perforation device illustrates a relatively simple implementation for multiple perforation using a perforating object, but should not be interpreted in a limiting manner. The points 31 could for example be replaced by blades to obtain grooves 1002, rather than holes 1001. Furthermore, an efficient and, if necessary, multi-zone heating system (not shown) for the perforating objects (needles, points, nails, etc.) can be put in place to facilitate the perforation of the organic structure 10. The temperature can then be adjusted according to the melting temperature of the polymers to be perforated by reducing the mechanical energy required for the perforation, or even by adapting the temperature to any variations in the composition of the organic structure 10. In the case of PV cell encapsulant, the melting temperatures of the encapsulant are typically between 60 and 90°C.The temperatures suitable for the processing step are approximately equal to or higher than the (highest) melting temperature involved to which approximately 10°C is added.

[0074] In a second version, the perforation device can be configured to implement one or more needle rollers 34 which may or may not be heated. This type of device is for example encountered, for a completely different purpose, in the production of food packaging or in the paper industry. It has the advantage of being able to be integrated into a continuous process. The penetration depth of the needles is continuously adjustable and makes it possible to determine the diameter of the hole 1001.

[0075] According to a third version, the perforation device can be configured to implement one or more grooved rollers 33. In the same way, the depth of the grooves 1002 is continuously adjustable and makes it possible to determine the width of the groove 1002 left in the organic structure 10 of the PV panel 1. It is possible to provide grooved rollers arranged in a different direction, for example perpendicularly, than that of the roller illustrated, in particular to obtain a cut into squares or diamonds of the organic structure 10.

[0076] A non-mechanical perforation device is also envisaged which implements a laser cutting device 30. Laser cutting can indeed be used as a method of perforating the organic structure 10 to promote the delamination of the PV panels 1. This cutting method is well known to those skilled in the art and makes it possible to increase productivity significantly. In addition, this technology is precise, does not deform the material or only slightly and is suitable for most materials. High-power lasers are generally used, but, in our case, medium-power lasers may be suitable, thus allowing a significant energy saving.

[0077] Example: Implementation of the pre-treatment step to promote pe- netration of CO2 molecules in an EVA type encapsulation polymer

[0078] As non-limiting examples, this type of polymer can be used for the encapsulation of OV 1 modules, light-emitting diodes or OLEDs, TFT type transistors, photodetectors for example of organic type. The pretreatment according to the method of the invention makes it possible to reduce the time required for the delamination of the multilayer polymer structure by pulsed CO2 SC.

[0079] According to the first step, the pre-treatment of the multilayer device 1 consists of the mechanical or physical perforation of the polymers constituting the organic structure 10, in order to increase the diffusion kinetics of the CO2 SC implemented in the second step, i.e. the treatment step. The depth of the perforations, their spacing, as well as their geometry, are adapted to the thickness of the organic structure 10 and the composition of the materials present.

[0080] According to the second step, i.e. the treatment step, CO2 absorption and depressurization cycles are implemented to delaminate the multilayer structure of the multilayer device 1. In the example of the PV panels 1, the “pulsed” method that is recommended to be implemented is described in patent FR 3088579 AL. It consists of carrying out several successive absorption (or pressurization) and depressurization cycles at different operating conditions. The first cycle carried out at 75°C, 130 bar and at a depressurization speed of 2.7 bar.s 1 makes it possible to separate the rear face 101 and to carry out the foaming of the encapsulant 1022, by creating penetration paths for the CO2. The second cycle carried out at 150 bar makes it possible to finalize the separation between the front face 11 made of glass and the encapsulant 1022 and to open the encapsulation of the PV cells 1021, to allow subsequent processing, and in particular the reuse of the glass plate 11.

[0081] The invention is not limited to the embodiments previously described and extends to all the embodiments covered by the claims.

Claims

Claims

1. Method for delaminating a multi-layer device (1) comprising at least one organic structure (10), the method comprising the following steps: • A step of pre-treatment of the multi-layer device (1) consisting of perforating (100) said at least one organic structure (10) in places, then • A step of treatment, in a reactor, of the multi-layer device (1) consisting of subjecting it to at least one cycle of pressurization and depressurization of a fluid (2).

2. Method according to the preceding claim, in which, the multilayer device (1) further comprising a front face (11) made of glass, the perforation (100) of said at least one organic structure (10) is carried out from a rear face (12) of the multilayer device (1) which is opposite its front face (11).

3. Method according to any one of the preceding claims, wherein said at least one organic structure (10) comprises a rear face (101) based on at least one polymer and a layer (102) comprising at least one transducer (1021) and where appropriate an encapsulant (1022) of said at least one transducer (1021), the encapsulant (1022) being based on at least one polymer.

4. A delamination method according to any one of the preceding claims, wherein at least one perforation (100), preferably each perforation (100), is made in a thickness of said at least one organic structure (10) of the multilayer device (1).

5. Method according to the preceding claim, in which at least one perforation (100), preferably each perforation (100), is made in the entire thickness of said at least one organic structure (10) of the multilayer device (1).

6. A delamination method according to any one of the preceding claims, wherein at least one perforation (100), preferably each perforation (100), of said at least one organic structure (10) is in the form of a hole (1001) or a groove (1002).

7. A delamination method according to any preceding claim, wherein each perforation (100) is located at a distance maximum less than or equal to 10 mm, preferably less than or equal to 7.5 mm, and even more preferably less than or equal to 5 mm, of another perforation (100).

8. A delamination method according to any one of the preceding claims, wherein the treatment step has a duration of less than 120 minutes, preferably less than 60 minutes and even more preferably less than 45 minutes.

9. A delamination method according to any one of the preceding claims, wherein the fluid (2) is chosen from: • carbon dioxide CO2; • sulfur hexafluoride; • nitrous oxide; • linear or branched alkanes, such as methane, propanes, butanes, and pentanes; • cyclic alkanes; • linear or branched alkenes, such as ethylene and propylene; • alcohols, such as methanol, ethanol, propanols, and butanols; and • mixtures thereof.

10. A delamination method according to any one of the preceding claims, wherein each pressurization and depressurization cycle comprises: • compression of the fluid (2) by increasing the pressure in the reactor to a pressure PI, at which the fluid is in a first physical state; then • decompression of the fluid (2) by decreasing the pressure in the reactor from the pressure PI to a pressure P2 at which the fluid is in a second physical state, the pressure P2 being lower than the pressure PI.

11. Method according to the preceding claim, in which said at least one cycle is preceded by contacting, in the reactor, the multilayer device (1) with the fluid (2) at a temperature T0, such as ambient temperature, and a pressure PO, such as the pressure at- spherical.

12. Delamination method according to any one of the preceding claims, free from a step of reducing the size of the multi-layer device (1), and in particular free from a step of grinding or crushing the multi-layer device (1).

13. A delamination method according to any preceding claim, wherein at least one perforation (100) is made using a laser (30).

14. A delamination method according to any preceding claim, wherein a plurality of perforations (100) are made simultaneously using a corresponding plurality of tips (31) extending from a same face of a plate (32).

15. A delamination method according to any preceding claim, wherein a plurality of perforations (100) are made using a ribbed (33) or spiked (34) roller.

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