How to handle ply elements

Abstract

The present invention relates to a method for treating a layer element, the layer element having at least one substrate including a lower surface and an upper surface located on the opposite side of the lower surface, a top layer at least partially transparent to visible light, and at least one adhesive layer arranged between the top layer and the upper surface, in which the adhesive layer is heated to an adhesive layer temperature and the lower surface of the substrate is cooled to a lower surface temperature.

Description

[Technical field]

[0001] The present invention relates to a method for treating a layer element, the layer element having at least one substrate with a lower surface and an upper surface located opposite the lower surface, a top layer at least partially transparent to visible light, and at least one adhesive layer arranged between the top layer and the upper surface. The present invention further relates to an apparatus for carrying out such a method. [Background technology]

[0002] A layer element in the sense of the present invention is, for example, a solar module having the above-mentioned layers. The term layer element is also to be understood as other parts and elements having the above-mentioned layers. Solar modules of the above-mentioned kind are becoming widely used in various forms to generate electric current from sunlight. These solar modules are, for example, arranged in small numbers on private roofs, for example on residential buildings, and can at least partially cover the power needs of the house in which they are installed. Such distributed energy supplies are also increasingly being used, for example to enable the decentralized charging of electric vehicles. However, solar modules of the above-mentioned kind are also used in larger installations on land otherwise used for agriculture, and for commercial electricity generation and transmission to the public power grid.

[0003] A disadvantage is that the service life of solar modules is limited. Expensive raw materials are used for the production of solar modules. For example, in many modules, the conductor tracks are made of silver. In the prior art, methods are presented that allow these raw materials to be recycled and reused for this reason alone. For solar modules in which metal components are arranged on a glass substrate, for example in JP 2014-054593 A, a method is proposed for mechanically removing these components. For solar modules with silicon substrates, the previously unpublished German patent specification DE 102021129301 A1 describes a method in which an adhesive layer arranged between the top layer and the conductor tracks is heated so that the top layer can be removed from the remainder of the solar module. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-054593 A [Patent Document 2] German Patent No. 102021120301 Summary of the Invention

[0005] The drawback of these methods is that they are not applicable to all solar modules having a silicon substrate. The invention is therefore based on the task of improving the methods so that they can be used for a wider range of different solar modules.

[0006] The present invention solves this problem by a method according to the preamble of claim 1, characterized in that in the method the adhesive layer is heated to the adhesive temperature and the underside of the substrate is cooled to the underside temperature. By heating the adhesive layer it is possible to remove the top layer from the remaining part of the layer element. The top layer is in particular a glass layer which is particularly preferably formed completely transparent to visible light. By heating the adhesive layer the adhesive strength of the adhesive layer is reduced and the top layer can be removed. The heat introduced into the adhesive layer is transferred through the layer element and gradually heats the other layers of the layer element and also the elements of the layer element. In many cases a plastic layer, for example made from polyvinyl fluoride (PVF), is arranged on the underside of the substrate. The material of this plastic layer is usually less heat resistant than the substrate, the top layer and especially the adhesive layer. The heat introduced to heat the adhesive layer can also heat up the plastic layer and decompose it, which can lead to the release of harmful and health-damaging gases. According to the present invention this is prevented by cooling the underside of the substrate to the underside temperature.

[0007] Treating a layer element in the sense of the present invention includes, for example, that the layer element is at least partially decomposed. In a preferred embodiment, this is done by completely or partially removing the top layer from the substrate. This is preferably done without damaging or destroying the top layer in the process. However, this does not necessarily have to be the case. It is also "treating" in the sense of the present invention when the top layer is completely or partially removed from the substrate and / or when it is damaged or destroyed before being completely or partially removed from the substrate.

[0008] This does not mean that the underside is cooled during the method, for example to a temperature below room temperature. The underside of the substrate of the layer element is at a temperature well below the underside temperature aimed for in the method before the start of the method. It merely means that heat is conducted from the underside of the substrate to achieve and in particular maintain the underside temperature, which is lower than the adhesive layer temperature.

[0009] A cooling device is present for cooling the underside of the substrate to an underside temperature, and heat is conducted away from the underside of the substrate by the cooling device.

[0010] The problem solved by the method according to the invention is, for example, that the conductor tracks of the layer elements of a solar module manufactured from precious raw materials are not accessible from the outside. They are located on the upper side of the substrate, but are covered by a top layer attached by at least one adhesive layer. The adhesive layer is heated, which reduces its adhesive effect, so that the top layer and the substrate can then be pulled apart from each other. The conductor tracks arranged on the upper side of the substrate can then be accessed. They are then removed from the substrate by mechanical removal, and the removed material is then received.

[0011] In particular, the layer element is a solar module, the layer element in particular having metal conductor tracks which are particularly preferably arranged on the upper side of the substrate and are covered by a top layer.

[0012] In particular, the adhesive layer temperature is at least 180°C, in particular at least 200°C, particularly preferably at least 230°C, and at most 400°C, in particular at most 350°C, particularly preferably at most 280°C. This is particularly advantageous if the adhesive layer is a layer consisting of or containing ethylene vinyl acetate (EVA). The adhesive layer temperature is particularly selected in such a way that no thermal decomposition of the adhesive layer occurs yet, with which some toxic and environmentally damaging gases can be released. This is avoided at temperatures below 400°C. At temperatures above 180°C, in particular above 200°C, acetic acid is released in the EVA adhesive layer, which forms a lubricating film between the layers bonded by the adhesive layer. This reduces the adhesive forces provided by the adhesive layer, and two elements bonded to one another can be separated from one another. Therefore, in particular, a film made of at least EVA is also used as the adhesive layer.

[0013] In particular, the underside temperature is at most 150° C., preferably at most 110° C., particularly preferably at most 100° C. The lower the temperature, the less the thermal influence on the layers arranged on the underside of the substrate.

[0014] In particular, the substrate has a structure consisting of a plurality of layers arranged adjacent to one another. The underside of the substrate forms the underside of the layer element to be treated by the method described herein. The substrate has, for example, a substrate made in particular of silicon, particularly preferably of silicon, and comprising charge-doped zones and vacancy-doped zones. Metal conductor tracks are arranged on the upper side of this substrate, which forms the upper side of the substrate. The underside of the substrate does not necessarily form the underside of the layer element. Other layers, such as the already mentioned plastic layer, can be arranged on the underside of the substrate. The underside of the substrate forms in particular the underside of the layer element.

[0015] In a preferred embodiment, the adhesive layer is heated by infrared radiation and / or electromagnetic induction and / or microwave radiation. In particular, when using infrared radiation or microwave radiation, it is advantageous to bring about the radiation through a top layer that is at least partially, but in particular completely transparent, in particular to the respective type of radiation. The infrared radiation used to heat the adhesive layer has in particular a wavelength of 1000-4000 nm, preferably 1000-2000 nm.

[0016] If microwave radiation is used, this in particular has a frequency of 2.4 GHz to 2.5 GHz, in particular 2.45 GHz. Alternatively, the microwave radiation has a frequency of 5.8 GHz.

[0017] In the case of heating by electromagnetic induction, alternating magnetic fields are used, in particular with frequencies between 1 kHz and 500 kHz. A usable frequency range 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. Preferably, the frequencies used are between 25 kHz and 300 kHz, particularly preferably between 25 kHz and 100 kHz.

[0018] The present invention further solves the above problem by an apparatus for carrying out the method described herein, characterized in that the apparatus comprises a heating device for heating the adhesive layer of the layer element to an adhesive layer temperature and a cooling device for cooling the underside of the substrate of the layer element to an underside temperature.

[0019] In particular, the apparatus has a holding device on which the layer elements to be processed by the apparatus are held. In particular, the apparatus has a worktable for supporting the layer elements, and the cooling device is arranged in particular in the worktable. In a particularly preferred embodiment, the worktable has a support surface on which the layer elements rest during the execution of the method. This support surface can be cooled in particular by a cooling device. The holding device for holding the layer elements is, for example, a tensioning device for applying a tensile force. This can, for example, have at least one negative pressure element, for example a suction element. The layer elements are, for example, positioned over an opening in the support surface that is closed by the layer elements. By applying negative pressure or suction to the closed opening, a suction force and therefore a tensile force is applied to the layer element, which holds the layer element on the support surface.

[0020] Alternatively or additionally, the holding device has a pressing device for applying a pressing force, by means of which the layer element is pressed against the rest surface. The pressing device has in particular at least one, in particular several, pressing members, which can be moved in particular relative to the rest surface. The pressing members are in particular moved away from the rest surface in order to place the layer element to be processed on the rest surface. The pressing members are then lowered until they come into contact with the layer element and can apply a pressing force to the layer element.

[0021] In particular, the cooling device has at least one fluid passage through which a cooling medium can be conducted. The cooling medium is, for example, a cooling liquid, such as water. In particular, the cooling device has a pump that can move the cooling medium through the fluid passage. If the fluid passage is located in the worktable, it is advantageous if it is made of a material with high thermal conductivity, such as, for example, a metal, such as aluminum or steel.

[0022] In particular, the at least one cooling channel is located as close as possible to the actual support surface of the worktable, for example at a distance of at most 15 cm, in particular at a distance of at most 10 cm, particularly preferably at a distance of at most 5 cm from the support surface. In particular, the material of the worktable, at least the material of the worktable located between the at least one cooling channel and the support surface, has a high thermal conductivity. The material is in particular a metal, for example aluminum or steel.

[0023] Alternatively or additionally, the cooling device comprises at least one blower capable of directing air to the underside of the layer element, which can be designed, for example, in the form of one or more ventilators arranged and aligned to move air in the direction of the underside of the layer element.

[0024] Alternatively or additionally, the cooling device has at least one device for discharging compressed air, which is then designed in such a way that compressed air coming from a compressed air source, which is in particular part of the cooling device but at least part of the device, is directed to the underside of the layer element. In the method described herein, in particular the underside of the layer element is cooled via a blower and / or a device for discharging compressed air.

[0025] In particular, the device comprises a first temperature sensor for detecting the adhesive layer temperature and / or a second temperature sensor for detecting the underside temperature, in particular the first temperature sensor and / or the second temperature sensor comprises a pyrometer, which can detect the resulting temperature, in particular without contact.

[0026] In particular, the device has an electronic controller, particularly preferably an electronic data processing device, which is configured to control the heating device and / or the cooling device depending on the detected adhesive layer temperature and / or the detected underside temperature. For this purpose, the respectively detected temperature is compared with a target temperature stored in the electronic data storage device. The target temperature can also be a temperature range within which the detected temperature should be. The electronic controller is configured to increase the power of the heating device and / or to increase the heating duration if the detected adhesive layer temperature is deemed too low compared to the stored target temperature. In particular, the electronic controller is alternatively or additionally configured to increase the power of the cooling device and / or to increase the cooling duration if the detected underside temperature is deemed too high compared to the stored target temperature.

[0027] In the following, some exemplary embodiments of the invention are explained in more detail with the aid of the accompanying drawings. [Brief description of the drawings]

[0028] [Figure 1] 1 is a schematic diagram of layer elements in a method. [Diagram 2] 1 is a schematic diagram of layer elements in a method. [Diagram 3] 1 is a schematic diagram of layer elements in a method. [Figure 4] 1 is a schematic diagram of layer elements in a method. [Diagram 5] 1 is a schematic diagram of layer elements in a method. [Figure 6] 1 is a schematic diagram of layer elements in a method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] FIG. 1 shows a layer element 2 designed as a solar module. It has a substrate 4, on whose upper side 6 conductor tracks (not shown) are located. The layer element 2 further has a top layer 8, for example made of glass. The top layer 8 is arranged on the substrate 4 by means of an adhesive layer 10. A back surface 16 is arranged on the bottom surface 12, which is located opposite the upper side 6 of the substrate 4, by means of another adhesive layer 14. In the method, for example, the layer element 2 is to be processed, by recycling it. For this purpose, the top layer 8 must first be removed. To achieve this, the adhesive layer 10 is heated, and in the exemplary embodiment shown in FIG. 1, a heat radiator 18 is used for this purpose. The top surface of the layer element 2 is heated by thermal radiation, which is shown diagrammatically. Since the top layer 8 is at least partially, but in particular completely transparent to radiation, which can also be visible light, such as laser radiation, the adhesive layer 10 is heated by thermal radiation and at least partially loses its adhesive effect.

[0030] The rear surface 16 of the layer element 2 is in contact with a worktable 20 on which a cooling device 22 is located. The cooling device is shown diagrammatically as a solid line and may for example have cooling channels through which a cooling medium is guided.

[0031] Figure 2 differs from Figure 1 only in that the cooling device 22 has been changed, which in Figure 2 is designed in the form of a number of ventilators 24, which direct air to the rear surface 16 of the layer element. This can be done, for example, through openings in the worktable.

[0032] 3 shows the layer element 2 and the heat radiator 18. In order to be able to determine the temperature of the top layer 8 and the rear surface 16, two temperature sensors 26 are present, which can be used to measure the corresponding temperatures and to transfer the measurement data to an electronic controller, not shown, which controls the heating and / or cooling devices.

[0033] In the embodiment shown in Fig. 4, the layer element 2 rests on a worktable 20 designed as a cooling plate 28. This cooling plate 28 is part of a cooling device 22, which in the illustrated exemplary embodiment further comprises cooling ribs 30, which are arranged on the side of the worktable 20 opposite the layer element 2. This makes it possible to dissipate heat that is transferred from the layer element 2 to the worktable 2 and to the cooling plate 28. The heat is dissipated, in particular, to the surrounding air. For this purpose, the cooling ribs 30 are cooled, in particular by at least one, in particular by several ventilators, not shown in Fig. 4.

[0034] Figure 5 shows another embodiment. The layer element 2 is positioned, as in Figure 1, on the worktable 20 on which the cooling device 22 is located. In the exemplary embodiment shown, a vacuum plate 32 is arranged between the layer element 2 and the part of the worktable 20 showing the cooling device, which applies a suction force to the layer element 2 and holds it to the worktable 20, of which in particular the vacuum plate 32 is part.

[0035] The figure largely corresponds to FIG. 1. The difference there is that in FIG. 6 the worktable 20 is not equipped with a holding device but, for example, with a suction device. That is to say, the layer element 2 can be moved on the upper surface of the worktable 20, for example in order to change the location that is heated by the heat radiator 18. For that purpose, rollers 34 are used, which are shown on the upper surface of the layer element 2. The rollers can be rotated in two directions, one of which is represented by the arrow shown in FIG. 6. [Explanation of symbols]

[0036] 2-layer elements 4 Base 6 Top side 8 Top Layer 10 Adhesive layer 12 Bottom side 14 Adhesive layer 16 Back side 18 Heat Radiator 20 Workbench 22 Cooling device 24 Ventilator 26 Temperature Sensor 28 Cooling Plate 30 Cooling Rib 32 Vacuum Plate 34 Lola

Claims

1. A method for treating a layer element, the layer element having at least one substrate including a lower surface and an upper surface opposite the lower surface, a top layer at least partially transparent to visible light, and at least one adhesive layer disposed between the top layer and the upper surface, characterized in that the adhesive layer is heated to an adhesive layer temperature and the lower surface of the substrate is cooled to a lower surface temperature.

2. 2. The method according to claim 1, characterized in that the layer element is a solar module, the layer element in particular having a metal conductor path, which is particularly preferably arranged on the top side of the substrate and is covered by the top layer.

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

4. 4. The method according to claim 1, wherein the temperature of the underside is at most 150°C, preferably at most 110°C, particularly preferably at most 100°C.

5. Method according to any one of claims 1 to 4, characterized in that the adhesive layer is heated by infrared radiation and / or electromagnetic induction and / or microwave radiation.

6. 6. An apparatus for carrying out the method according to claim 1, characterized in that it comprises a heating device for heating the adhesive layer of the layer element to an adhesive layer temperature and a cooling device for cooling the underside of the substrate of the layer element to an underside temperature.

7. 7. Apparatus according to claim 6, characterized in that the apparatus comprises a worktable for supporting the layer elements, and the cooling device is arranged on the worktable.

8. 8. Apparatus according to claim 6 or 7, characterized in that the cooling device comprises at least one fluid passage through which a cooling medium can be conducted.

9. 9. Apparatus according to any one of claims 6 to 8, characterized in that the cooling device comprises at least one blower capable of directing air onto the underside of the layer element.

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

11. The apparatus according to claim 10, characterized in that the apparatus comprises an electrical controller, in particular an electronic data processing device, configured to control the heating device and / or the cooling device depending on the detected adhesive layer temperature and / or the detected underside temperature.

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