Method for processing layer element

Abstract

The invention relates to a method for processing a layer element, said layer element having at least one main body with an underside and an upper side opposite the underside; the invention relates to a method for manufacturing a substrate, comprising a substrate, an upper side, a cover layer which is at least partially permeable to visible light, and at least one adhesive layer which is arranged between the cover layer and the upper side, the adhesive layer being heated to an adhesive layer temperature and the lower side of the substrate being cooled to a lower side temperature.

Description

Technical Field

[0001] The invention relates to a method for processing a layer element, wherein the layer element has at least one base body with a bottom side and an upper side opposite the bottom side, a cover layer at least partially transparent to visible light, and at least one adhesive layer arranged between the cover layer and the upper side. The invention also relates to a device for carrying out such a method. Background Art

[0002] Layer elements in the sense of the present invention are, for example, solar cell modules having the above-mentioned layers. The term "layer element" can also be understood as other components and elements having the above-mentioned layers. Solar cell modules of the above-mentioned type are increasingly used to generate electric current from sunlight. These solar cell modules can, for example, be installed in small quantities on private roofs, such as residential buildings, in order to at least partially meet the electricity demand of the house where the solar cell modules are installed. This decentralized energy supply is also increasingly used, for example, to be able to charge electric vehicles in a decentralized manner. However, solar cell modules of the above-mentioned type are also used in large-scale installations other than agricultural land in order to generate electricity commercially and feed the electricity into the public power grid.

[0003] Disadvantageously, solar cell modules have only a limited service life. Expensive raw materials are used in the manufacture of solar cell modules. Conductor tracks are made of silver, for example, in a large number of modules. For this reason alone, methods are described in the prior art that allow these raw materials to be recovered and reused. For solar cell modules with metal components arranged on a glass substrate, a method is proposed, for example, in JP 2014 / 054593A, in which these components are mechanically removed. For solar cell modules with a silicon substrate, a method is described in the unpublished DE 10 2021 129 301, in which an adhesive layer arranged between a cover layer and the conductor tracks is heated so that the cover layer can be removed from the rest of the solar cell module.

[0004] Disadvantageously, this method is also not applicable to all solar cell modules having a silicon substrate. The present invention is therefore based on the object of improving the method in such a way that it can be used for a wider range of different solar cell modules. Summary of the invention

[0005] The present invention solves the proposed task by a method according to the preamble of claim 1, the method being characterized in that, in the method, the adhesive layer is heated to the adhesive layer temperature and the bottom side of the substrate is cooled to the bottom side temperature. By heating the adhesive layer, the cover layer can be removed from the rest of the layer element. The cover layer is preferably constructed as a glass layer that is particularly preferably completely transparent to visible light. By heating the adhesive layer, the adhesion of the adhesive layer is reduced and the cover layer can be removed. The heat introduced into the adhesive layer diffuses in the layer element and gradually heats the other layers and elements of the layer element. A plastic layer, such as a plastic layer composed of polyvinyl fluoride (PVF), is usually arranged on the bottom side of the substrate. The material of the plastic layer is usually less heat-resistant than the substrate, the cover layer and the adhesive layer in particular. The heat introduced to heat the adhesive layer also heats and may decompose the plastic layer, wherein harmful and unhealthy gases may be released. This is prevented according to the present invention by cooling the bottom side of the substrate to the bottom side temperature.

[0006] In the sense of the present invention, processing of a layer element comprises, for example, at least partial removal of the layer element. In a preferred embodiment, this occurs by removing the cover layer in whole or in part from the substrate. This preferably occurs without damaging or destroying the cover layer. However, this is not necessarily the case. Even if the cover layer is damaged or destroyed when and / or before being removed in whole or in part from the substrate, this is also "processing" in the sense of the present invention.

[0007] This does not mean that the underside is cooled during the method, for example to a temperature below room temperature. Before the method begins, the temperature of the underside of the base body of the layer element is significantly lower than the underside temperature sought during the method. It only means that heat is dissipated from the underside of the base body in order to achieve and preferably maintain the underside temperature. The underside temperature is lower than the adhesive layer temperature.

[0008] In order to cool the underside of the base body to the underside temperature, a cooling device is provided, by which heat is dissipated from the underside of the base body.

[0009] The difficulty overcome by the method according to the invention is that, for example, the conductor tracks of the layer elements of a solar cell module made of precious raw materials cannot be contacted from the outside. Although the conductor tracks are located on the upper side of the substrate, they are covered by a cover layer, which is fixed by at least one adhesive layer. By heating the adhesive layer, its adhesion effect is reduced, so that the cover layer and the substrate can then be removed from each other. The conductor tracks arranged on the upper side of the substrate are then contactable. The conductor tracks can now be removed from the substrate by mechanical removal and the material removed for this purpose can be collected.

[0010] The layer element is preferably a solar cell module, wherein the layer element preferably comprises metallic conductor tracks which are particularly preferably arranged on the top side of the base body and are covered by the covering layer.

[0011] Preferably, the temperature of the adhesive layer is at least 180°C, preferably at least 200°C, particularly preferably at least 230°C and a maximum of 400°C, preferably a maximum of 350°C, particularly preferably a maximum of 280°C. This is particularly advantageous if the adhesive layer is made of ethylene-vinyl acetate (EVA) or a layer made of ethylene-vinyl acetate (EVA). The adhesive layer temperature is preferably selected so that no thermal decomposition of the adhesive layer occurs, which partially releases toxic and environmentally harmful gases. This is avoided when the temperature is below 400°C. When the temperature exceeds 180°C, preferably exceeds 200°C, acetic acid is released in the EVA adhesive layer, which forms a lubricating film between the layers connected by the adhesive layer. As a result, the adhesion applied by the adhesive layer is reduced and two interconnected elements can be separated from each other. Therefore, it is preferred to use at least a film composed of EVA as the adhesive layer.

[0012] The underside temperature is preferably at most 150° C., preferably at most 110° C., particularly preferably at most 100° C. The lower the temperature, the less the thermal effect on the layers arranged on the underside of the base body.

[0013] Preferably, the base body has a structure consisting of a plurality of layers arranged in succession. The bottom side of the base body forms the bottom side of the layer element processed by the method described here. The base body has, for example, a substrate which is preferably made of silicon, in particular composed of silicon, and has charge-doped regions and hole-doped regions. Metallic conductor tracks are arranged on the upper side of the substrate, which forms the top side of the base body. The bottom side of the substrate does not necessarily have to form the bottom side of the layer element. Further layers, for example the plastic layer already mentioned, are arranged on the bottom side of the substrate. The bottom side of the base body preferably forms the bottom side of the layer element.

[0014] In a preferred embodiment, the adhesive layer is heated by means of infrared radiation and / or magnetic induction and / or microwave radiation. In particular, when using infrared radiation or microwave radiation, it is advantageous to apply the radiation via a cover layer, which is preferably at least partially, but preferably completely, transparent to the corresponding type of radiation. The infrared radiation used to heat the adhesive layer has a wavelength of preferably 1000 to 4000 nm, preferably 1000 to 2000 nm.

[0015] If microwave radiation is used, it preferably has a frequency between 2.4 GHz and 2.5 GHz, preferably 2.45 GHz. Alternatively, the microwave radiation has a frequency of 5.8 GHz.

[0016] When heating by means of magnetic induction, an alternating magnetic field is used, the frequency of which is preferably between 1 kHz and 500 kHz. The frequency range that can be used is called the low-frequency range and includes frequencies between 1 kHz and 7 kHz. Another frequency range is called the medium-frequency range and includes frequencies between 8 kHz and 40 kHz. The high-frequency range includes frequencies between 60 kHz and 500 kHz. The frequencies used are preferably between 25 kHz and 300 kHz, particularly preferably between 25 kHz and 100 kHz.

[0017] The invention also solves the proposed object by a device for carrying out one of the methods described herein, which is characterized in that the device has a heating device for heating the adhesive layer of the layer element to an adhesive layer temperature and a cooling device for cooling the bottom side of the base body of the layer element to a bottom side temperature.

[0018] The device preferably has a holding device, by means of which the layer elements processed by means of the device are held. The device preferably has a workbench for carrying the layer elements, wherein the cooling device is preferably arranged in the workbench. In a particularly preferred configuration, the workbench has a placement surface, on which the layer elements are placed during the execution of the method. Preferably, the placement surface can be cooled by the cooling device. The holding device for holding the layer elements is, for example, a traction device for applying a tensile force. The traction device, for example, has at least one negative pressure element, such as a suction element. The layer elements are, for example, positioned on openings in the placement surface, which are closed by the layer elements. Suction force and thus tensile force are applied to the layer elements by applying a negative pressure or a suction force to the closed openings, and the suction force and thus tensile force hold the layer elements on the placement surface.

[0019] Alternatively or additionally to this, the holding device has a pressing device for applying pressure. The layer element is pressed onto the placement surface by this pressure. The pressing device preferably has at least one, preferably a plurality of pressing devices. These pressing devices are preferably movable relative to the placement surface. The pressing device is preferably removed from the placement surface in order to arrange the layer element to be processed on the placement surface. The pressing device is then lowered until it contacts the layer element and can apply pressure to the layer element.

[0020] The cooling device preferably has at least one fluid channel through which a cooling medium can be guided. The cooling medium is, for example, a cooling liquid, such as water. The cooling device preferably has a pump, by means of which the cooling medium can be moved through the fluid channel. If the fluid channel is located in the workbench, it is advantageous if the fluid channel is made of a material with high thermal conductivity, for example a metal, such as aluminum or steel.

[0021] The at least one cooling channel is preferably as close as possible to the actual placement surface of the workbench, for example at most 15 cm, preferably at most 10 cm, particularly preferably at most 5 cm from the placement surface. Preferably, the material of the workbench, at least the material of the workbench located between the at least one cooling channel and the placement surface, preferably has a high thermal conductivity. The material is preferably metal, for example aluminum or steel.

[0022] Alternatively or additionally, the cooling device has at least one blower, by which air can be directed to the underside of the layer element. The blower can be constructed, for example, in the form of one or more fans, which are arranged and oriented so that the fan moves the air in the direction of the underside of the layer element.

[0023] Alternatively or additionally thereto, the cooling device has at least one device for ejecting compressed air. The device is arranged in such a way that compressed air from a compressed air source is directed to the underside of the layer element, the compressed air source being preferably part of the cooling device, but at least part of the device. In the method described here, the underside of the layer element is preferably cooled by a blower and / or the device for ejecting compressed air.

[0024] The device preferably has a first temperature sensor for detecting the temperature of the adhesive layer and / or a second temperature sensor for detecting the temperature of the underside. The first temperature sensor and / or the second temperature sensor preferably has a pyrometer, by which the occurring temperature can be detected preferably contactlessly.

[0025] The device preferably has an electric control device, particularly preferably an electronic data processing unit, which is configured to control the heating device and / or the cooling device according to the detected adhesion layer temperature and / or the detected lower side temperature. For this purpose, each detected temperature is compared with a target temperature stored in an electronic data storage device. The target temperature can also be a temperature range, and the detected temperature should be within this temperature range. The electric control device is configured so that if the detected adhesion layer temperature is considered to be too low after comparison with the stored target temperature, the electric control device increases the power of the heating device and / or increases the duration of heating. Preferably, the electric control device is additionally or alternatively configured so that if the detected lower side temperature is considered to be too high after comparison with the stored target temperature, the electric control device increases the power of the cooling device and / or increases the duration of cooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Some embodiments of the present invention are described in detail below with the aid of the accompanying drawings. The accompanying drawings show:

[0027] Figure 1-6 : Schematic diagram of the layer elements in the method. DETAILED DESCRIPTION

[0028] Figure 1 A layer element 2 is shown, which is designed as a solar cell module. The solar cell module has a base body 4, on the upper side 6 of which conductor tracks (not shown in the drawing) are located. The layer element 2 also has a covering layer 8, which is made of glass, for example. The covering layer 8 is arranged on the base body 4 by means of an adhesive layer 10. On the lower side 12 of the base body 4, opposite the upper side 6, a back side 16 is arranged by means of a further adhesive layer 14. In the method, the layer element 2 is to be processed, for example, by recycling. For this purpose, the covering layer 8 must first be removed, and in order to achieve this, the adhesive layer 10 is heated, for which purpose Figure 1 In the embodiment shown, a radiant heater 18 is used. The schematically shown thermal radiation heats the upper side of the layer element 2. Since the cover layer 8 is at least partially, but preferably completely, transparent to radiation (also visible light, for example laser radiation), the adhesive layer 10 is heated by the thermal radiation and thus at least partially loses its adhesive effect.

[0029] The back side 16 of the layer element 2 is in contact with a workbench 20 in which a cooling device 22 is located. The cooling device is schematically indicated as a solid line and can have, for example, cooling channels through which a cooling medium is conducted.

[0030] Figure 2 and Figure 1 The only difference is the change of the cooling device 22, which is Figure 2 In the form of a plurality of fans 24, air is directed to the rear side 16 of the layer element by means of the fans. This can be achieved, for example, by openings in the workbench.

[0031] Figure 3 The layer element 2 and the radiant heater 18 are shown. Two temperature sensors 26 are provided to determine the temperature of the cover layer 8 and the back side 16. The two temperature sensors can measure the corresponding temperatures and transmit the measurement data to an electrical control device (not shown) which controls the heating and / or cooling device.

[0032] exist Figure 4 In the embodiment shown, the layer element 2 is placed on a workbench 20 designed as a cooling plate 28. The cooling plate 28 is part of a cooling device 22. In the embodiment shown, the cooling device 22 also has cooling ribs 30, which are arranged on the side of the workbench 20 facing away from the layer element 2. In this way, the heat transferred from the layer element 2 to the workbench 2 and the cooling plate 28 can be dissipated. The heat is preferably released to the surrounding air. For this purpose, the cooling ribs 30 are preferably provided by means of at least one, preferably a plurality of Figure 4 Cooling by fans not shown.

[0033] Figure 5 Another configuration is shown. The layer element 2 is positioned as shown in FIG. Figure 1 The cooling device 22 is shown on the workbench 20. In the embodiment shown, a vacuum plate 32 is arranged between the layer element 2 and the part of the workbench 20 except the cooling device, which applies a suction force to the layer element 2 and thus holds the layer element on the workbench 20, and the vacuum plate 32 is preferably part of the workbench.

[0034] Figure 6 To a large extent Figure 1 Corresponding. But Figure 1 Differently, in Figure 6 In the embodiment, the table 20 is not equipped with a holding device, such as a suction device. Therefore, the layer element 2 can be moved on the upper side of the table 20, for example, in order to change the location heated by the radiant heater 18. For this purpose, the rollers 34 shown on the upper side of the layer element 2 are used. The rollers can rotate in two directions, one of which is by Figure 6 The arrows shown in .

[0035] Reference numerals list

[0036] 2-layer components

[0037] 4 Matrix

[0038] 6 upper side

[0039] 8 Covering Layer

[0040] 10 Adhesion layer

[0041] 12 Lower side

[0042] 14 Adhesion layer

[0043] 16 Dorsal

[0044] 18 Radiant Heater

[0045] 20 Workbench

[0046] 22 Cooling device

[0047] 24 Fan

[0048] 26 Temperature Sensor

[0049] 28 Cooling Plate

[0050] 30 Cooling ribs

[0051] 32 Vacuum Plate

[0052] 34 rollers

Claims

1. A method for processing a layer element, wherein: The layer element comprises at least one substrate, a covering layer which is at least partially transparent to visible light, and at least one adhesion layer, wherein the substrate has a bottom side and an upper side opposite the bottom side, and the adhesion layer is arranged between the covering layer and the upper side, characterized in that in the method, the adhesion layer is heated to an adhesion layer temperature and the bottom side of the substrate is cooled to a bottom side temperature.

2. The method according to claim 1, characterized in that The layer element is a solar cell module, wherein the layer element preferably comprises metallic conductor tracks which are particularly preferably arranged on the top side of the base body and are covered by the covering layer.

3. The method according to claim 1 or 2, characterized in that: The bonding layer temperature is at least 180°C, preferably at least 200°C, particularly preferably at least 230°C and at most 400°C, preferably at most 350°C, particularly preferably at most 280°C.

4. The method according to any one of the preceding claims, characterized in that The underside temperature is at most 150°C, preferably at most 110°C, particularly preferably at most 100°C.

5. The method according to any one of the preceding claims, characterized in that The adhesive layer is heated by means of infrared radiation and / or magnetic induction and / or microwave radiation.

6. A device for carrying out the method according to any one of the preceding claims, characterized in that The device has a heating device for heating the adhesive layer of the layer element to the adhesive layer temperature and a cooling device for cooling the underside of the base body of the layer element to the underside temperature.

7. The device according to claim 6, characterized in that The apparatus has a table for carrying the layer elements, wherein the cooling device is arranged in the table.

8. The device according to claim 6 or 7, characterized in that The cooling device has at least one fluid channel through which a cooling medium can be conducted.

9. The device according to any one of claims 6 to 8, characterized in that The cooling device has at least one blower, by means of which air can be directed onto the underside of the layer elements.

10. The device according to any one of claims 6 to 9, characterized in that The device has a first temperature sensor for detecting the temperature of the adhesive layer and / or a second temperature sensor for detecting the temperature of the underside.

11. The device according to claim 10, characterized in that The device has an electrical control device, preferably an electronic data processing device, which is designed to control the heating device and / or the cooling device as a function of the detected adhesion layer temperature and / or the detected underside temperature.

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