Method and apparatus for processing solar modules

Abstract

The present invention relates to a method for processing a solar module, the solar module having at least one silicon base body having charge doped zones, hole doped zones and a top surface, metal conductor tracks on the top surface of the base body, a surface layer that is at least partially transparent to visible light, but preferably transparent to visible light, and at least one adhesive layer arranged between the surface layer and the conductor tracks, the method comprising the steps of heating the at least one adhesive layer, removing the cover layer from the base body, mechanically removing the conductor tracks and collecting the machined material.

Description

Technical Field

[0001] The present invention relates to a method for processing a solar module, the solar module comprising at least one silicon-based body having a charge-doped zone, a hole-doped zone and an upper surface, a metal conductor track on the upper surface of the base body, a cover layer which is at least partially transparent to visible light, preferably transparent to visible light, and at least one adhesive layer disposed between the cover layer and the conductor track. The present invention also relates to an apparatus for carrying out such a method.

Background Art

[0002] Solar modules of the above type are being used increasingly to generate electricity from sunlight. For example, the solar modules may be arranged in small numbers on the roofs of private buildings, such as residential buildings, to at least partially meet the electrical demand of the building to which the solar module is attached. This use of this type of distributed energy supply is increasing, for example, for the distributed charging of electric vehicles. However, solar modules of the type described above are also used in large-scale installations on other agricultural land to generate commercial electricity and supply it to the public grid.

[0003] A drawback is the limited lifespan of solar modules. Expensive raw materials are used during the manufacture of solar modules. For example, conductor tracks are manufactured from silver for a large number of modules. For this reason alone, there is a need for a way to recycle the aforementioned raw materials and make them available for reprocessing. However, the increasing number of solar modules that reach the end of their lifespan and are discarded also creates a large amount of waste that should be recycled or at least processed, especially from the standpoint of the environmental compatibility of power generation, for which solar modules and power generation from sunlight are symbolic. With regard to solar modules containing metal components placed on a glass substrate, JP2014 / 054593A proposes a method for mechanically removing the components. The glass described in the publication can withstand mechanical stress, and this is precisely why these substrates are described and disclosed therein. With regard to other substrates, the only method known to date from the prior art is to use a wet chemical process, which is disadvantageous due to the high cost, the materials used (often harmful to the environment and / or health), and the high level of labor involved.

[0004] Therefore, the present invention is based on the objective of proposing a method that can eliminate or at least reduce the drawbacks of the prior art. [Overview of the Initiative]

[0005] The present invention solves the problems addressed by the above-described type of method, which comprises the steps of heating at least one adhesive layer, removing the cover layer from the base body, and mechanically removing the conductor track and collecting the machined material.

[0006] One difficulty eliminated by the method according to the present invention is that the conductor tracks of a solar module, manufactured from valuable raw materials, are not accessible from the outside. These are located on the top surface of the base body but are covered by a cover layer secured by at least one adhesive layer. By heating the adhesive layer, its adhesive effect is reduced, and then the cover layer and the base body can be separated from each other. In this case, the conductor tracks located on the top surface of the base body become accessible. These are removed from the base body by mechanical removal, and the removed material is collected.

[0007] Preferably, the adhesive layer is heated by infrared radiation and / or magnetic induction and / or microwave radiation. Heating is carried out to temperatures above 180°C, preferably above 200°C, particularly preferably above 230°C, and below 400°C, preferably below 350°C, particularly preferably below 280°C. When using infrared or microwave radiation in particular, it is advantageous to apply the radiation through a cover layer that is preferably at least partially, but preferably completely transparent to each type of radiation. The infrared radiation used for this purpose preferably has wavelengths of 1000 to 4000 nm, preferably 1000 to 2000 nm. The preferred temperature is below 400°C. Above this temperature, thermal decomposition occurs, during which toxic and environmentally harmful gases are released. This can be avoided at temperatures below 400°C. At temperatures above 180°C, preferably above 200°C, it is preferable that acetic acid is released into the adhesive layer, thereby forming a lubricating film between the layers connected by the adhesive layer, i.e., preferably between the base body and the cover layer. This reduces the adhesive force applied by the adhesive layer, allowing the two connected elements to separate from each other. Preferably, at least one film of ethylene vinyl acetate (EVA) is also used as the adhesive layer, which releases acetic acid when heated within the temperature range mentioned.

[0008] After the adhesive layer has been heated to the desired temperature, the heat source can be switched off, or the temperature can be controlled to remain constant for a certain period of time, for example, 10 minutes, in order to process the solar module at this temperature. Heating is preferably carried out over the entire surface so that the entire adhesive layer of the solar module being processed is heated uniformly. Alternatively, it is possible to heat only a portion of the adhesive layer and move the heat source relative to the solar module, for example, or vice versa. During heating, the solar module is preferably in a vacuum, i.e., subjected to negative pressure. However, heating under normal pressure is also possible.

[0009] When electromagnetic radiation is used as a heat source, the electromagnetic radiation can be introduced directly into the adhesive layer to be heated through a cover layer that is at least partially transparent to the radiation. Unlike when using magnetic induction, the adhesive layer is generally not magnetic or generally cannot be magnetized. In this case, the induced magnetic field heats another layer of the solar module, preferably the base body which may also be called a substrate or wafer, and as a result releases heat to the adhesive layer placed on top of it.

[0010] In addition to or instead of the heat sources mentioned above, a laser can also be used to heat at least one adhesive layer.

[0011] In a preferred embodiment, the cover layer is removed from the base body by applying a force in opposite directions, for example, by applying a tensile force in opposite directions to the cover layer and the base body. In this case, the tensile force in opposite directions can be applied perpendicular to the upper side of the base body. With respect to a solar module located on a work surface, this means that the tensile forces act upward and downward. For this purpose, a negative pressure element, such as a suction element, is preferably used. The substrate is preferably placed on a work surface having an opening, and the opening is then sealed by the substrate. By applying negative pressure or suction force to the sealed opening, a suction force, and therefore a tensile force, is exerted on the substrate holding it on the work surface. Preferably, at least one suction element or at least one suction pad is applied to the cover layer, which is configured to apply a suction force to the cover layer, which is directed away from the work surface, i.e., it acts generally upward. As a result, two opposing forces are applied, separating the cover layer from the substrate.

[0012] Alternatively or additionally, at least one slide is used to apply a force to the cover layer acting parallel to the work surface on which the substrate is placed. The substrate is preferably held in place by the aforementioned attractive force on the work surface. Alternatively or additionally, the work surface has an end stop that protrudes from the work surface and rests on the substrate. The substrate is placed on the end stop in such a way that movement of the substrate caused by the force applied by the slide is prevented and impossible. When the slide applies force to the first side of the cover layer, the substrate is preferably placed with the opposite side on the projection.

[0013] Alternatively, a tensile force in the opposite direction can be applied parallel to the top surface of the base body. This generates a shear force that can separate the two components from each other.

[0014] In a preferred embodiment, the cover layer is damaged or broken before the adhesive layer is heated or before the cover layer is removed from the base body. In this process, the cover layer is preferably divided into several parts by mechanical stress. For example, this can be achieved by striking the cover layer with a hammer. In this case, the cover layer consists of several individual parts, most of which, preferably all of which, are bonded to the base body via the adhesive layer. The individual parts can then be removed from the base body in the manner described above.

[0015] When the cover layer and the base body are separated from each other so that they move in parallel, especially when the conductor track is positioned on the upper side of the base body, very little bending moment is applied, and as a result, the risk of the base body breaking is reduced. This has the advantage of mechanically removing the conductor track from the base body, and the less mechanical damage there is to the base body, the easier it is to do so.

[0016] Preferably, before removing the cover layer, the cover layer is damaged with a tool, preferably a spatula, scraper, knife, or wire, the tool preferably inserted between the cover layer and the base body. Preferably, the cover layer is completely damaged so that individual parts of the cover layer can be removed more easily, in contrast to what happens with a base body that is not damaged and does not have cracks after the cover surface is removed.

[0017] Preferably, at least one adhesive layer is also removed, at least partially, but preferably completely, when the cover layer is removed. This means that as little of the adhesive layer remaining on the upper surface of the base body and therefore on the conductor track as possible. These portions are collected together with the material removed during the mechanical removal of the conductor track. In that case, they must be potentially separated from the conductor track material in a complex and costly manner.

[0018] Therefore, once the cover layer is removed, the adhesive layer is preferably removed at least partially, but preferably completely. In this case, if the adhesive layer is no longer sufficiently warm, it may be advantageous to reheat the remaining portion of the adhesive layer.

[0019] Particularly preferably, a mechanical tool such as a wire, spatula, scraper, blade, knife, or brush is used to remove at least one adhesive layer after the cover layer has been removed.

[0020] Preferably, the conductor track is removed by brushing, milling, planing, shaping, scraping, chiseling, broaching, blasting, and / or grinding. Removal can be carried out using geometrically defined or geometrically indeterminate cutting edges. The material to be removed can also be removed using tension brushes, such as round brushes, disc brushes, brushes, roller brushes, hand brushes, and / or strip brushes. The brushes may be made of iron, plastic, brass, or other materials or mixtures of materials. The diameter and length of the bristles may vary. The brushes can be moved in a rotational, vibrating, or linearly or eccentrically. In a preferred embodiment, a rotary roller brush having steel wire is used, which rotates at 2000 to 8000 revolutions per minute.

[0021] The brush can act across the entire surface or on a section-by-section basis, and can be force-controlled and / or path-controlled.

[0022] For milling, a surface cutting tool with a tool axis perpendicular to the surface to be removed is preferably used. Other tools, such as blades or knives, are preferably made from steel, cubic boron nitride (CBN), aluminum oxide ceramic, polycrystalline diamond (PCD), silicon nitride ceramic, or high-speed steel (HSS). Coated carbides, tungsten carbide-based carbides, or fine carbides can also be used as materials for these tools. The blade may be oriented at different angles to the conductor track, with a 45° angle being advantageous. The knife position may change depending on the grinding of the blade. The blade can move oscillating and / or linearly, and can be force-controlled and / or path-controlled, for example. Removal can be performed over the entire surface or in sections. At least one blade is used.

[0023] Pendulum grinding is a preferred method for grinding using a rotary tool. The grinding wheel is preferably a CBN wheel or a diamond wheel. When belt grinding is performed, the belt is preferably oriented parallel to the cover layer being machined. The belt edges may be oriented parallel to the conductor track. It can be removed across the entire surface or in sections.

[0024] The removed material is collected. Preferably, it is sucked up into a container and collected. For this purpose, it is advantageous if the tools used for removal are already inside the box or bell, as this makes it possible to collect the removed dust as easily as possible. The material can be collected by an airflow or a liquid flow consisting of, for example, water or oil. However, it is preferable that no liquid is used, since the removed chips or dust must then be dried.

[0025] The problem addressed by the invention is solved by a device for carrying out the method described herein, comprising at least one heating device for heating at least one adhesive layer, at least one traction device for applying a tensile force, a mechanical removal device, and a collecting device. Preferably, the traction device has at least one, preferably a plurality of vacuum grippers and / or at least one, preferably a plurality of Bernoulli grippers.

[0026] In a preferred embodiment, the device also has an electric control unit, the removal device has at least one mechanical tool, and the electric control unit is configured to control at least one operating parameter of the at least one mechanical tool. The at least one operating parameter is preferably the contact pressure, path, or force. The electric control unit is preferably an electronic data processing device and is preferably part of the device. However, it is also sufficient if the electronic data processing device is not part of the device and the device communicates with the electronic data processing device via a communication device.

[0027] In the following, examples of embodiments of the invention will be explained in more detail with the aid of the accompanying drawings.

Brief Description of the Drawings

[0028] [Figure 1] Figure 1 is a process step in the method according to an example of a first embodiment of the invention. [Figure 2] Figure 2 is a process step in the method according to an example of a first embodiment of the invention. [Figure 3] Figure 3 is a process step in the method according to an example of a first embodiment of the invention. [Figure 4] Figure 4 is a process step in the method according to an example of a first embodiment of the invention.

[0029] Figure 1 depicts a solar module 2 comprising a substrate 4 on which conductor tracks 6 are arranged. The conductor tracks 6 are covered by a cover layer 8, which is fixed to the substrate 4 via an adhesive layer 10 surrounding the conductor tracks 6. The solar module 2 is placed on a work surface 12, which in the shown embodiment comprises two openings 14, these openings 14 being sealed by the substrate 4 placed on the work surface 12. A suction device 16, shown only schematically, is positioned beneath each of the openings 14. The suction device 16 is configured to apply negative pressure to the openings 14, thereby exerting an attractive force on the substrate 4 of the solar module 2. In the process step according to Figure 1, the solar module 2 is heated from above by electromagnetic radiation 18, for example, generated by a laser. The cover layer 8 is at least partially transparent to visible light, but preferably completely transparent, so that the electromagnetic radiation 18 passes through the cover layer 8 and heats the adhesive layer 10.

[0030] Figure 2 illustrates the subsequent process steps. The solar module 2 is still on the work surface 12. The substrate 4 is still held on the work surface 12 by the suction device 16. In this process step, the suction pad acts on the cover layer 8, exerting an upward force on the cover layer 8. This means that two opposing forces act between the substrate 4 and the cover layer 8, thus removing the cover layer 8 from the substrate 4.

[0031] Figure 3 illustrates the situation in the next process step. The substrate 4 remains held on the work surface 12, and the conductor track 6 is located on the side of the substrate 4 facing away from the work surface 12. The conductor track is still at least partially surrounded by the adhesive layer 10 even after the cover layer 8 has been removed from the substrate 4. This is shown in Figure 3, where the adhesive layer 10 is significantly thinner compared to the adhesive layer 10 in Figures 1 and 2. This is not a realistic depiction. When the cover layer 8 is removed from the substrate 4, a portion of the adhesive layer 10 is also removed. However, depending on the heating conditions and adhesive properties, this occurs irregularly and is never uniform. There may be areas where the adhesive layer 10 is completely removed. There may also be areas where the conductor track 6 is completely surrounded by the adhesive layer 10. The remaining portion of the adhesive layer 10 shown in Figure 3 is removed in this process step by a tool 22, which may be, for example, a spatula or a knife.

[0032] In Figure 4, the adhesive layer 10 has been completely removed from the upper side of the substrate 4. The conductor track 6 remains positioned on the upper side of the substrate 4. This, too, is a schematic representation and not a realistic one. In this process step, residue of the adhesive layer 10 remains on the upper surface of the substrate 4. The conductor track 6 is removed from the substrate 4 by a brush 24 that, in the illustrated embodiment, is shifted clockwise during rotation and moves relative to the upper surface of the substrate 4. The material 26 is bounced up and then collected by a suction cup 28 and fed for further processing.

[0033] Code List 2 solar modules 4 circuit boards 6 Conductor Tracks 8. Cover layer 10 adhesive layers 12 work surfaces 14 aperture 16 suction device 18 Electromagnetic radiation 20 suction pads 22 tools 24 brushes 26 materials 28 suction cups The invention described in the original claims of this application is listed below. [1] A method for processing a solar module, wherein the solar module is A silicon-based body having an electric doping zone, a hole doping zone, and a top surface, The metal conductor track on the upper surface of the base body, A cover layer which is at least partially transparent to visible light, and preferably transparent to visible light, The system comprises at least one adhesive layer disposed between the cover layer and the conductor track, The aforementioned method, a) The step of heating the at least one adhesive layer, b) The step of removing the cover layer from the base body, c) A method comprising the steps of mechanically removing the conductor track and collecting the machined material. [2] The method according to [1], characterized in that the adhesive layer is heated by infrared radiation and / or magnetic induction and / or microwave radiation to a temperature higher than 180°C, preferably higher than 200°C, particularly preferably higher than 230°C, and lower than 400°C, preferably lower than 350°C, particularly preferably lower than 280°C. [3] The method according to [1] or [2], characterized in that the cover layer is removed from the base body by applying a force acting in opposite directions to the cover layer and the base body, for example by applying a tensile force acting in opposite directions. [4] The method according to any one of [1] to [3], characterized in that, before removing the cover layer, the cover layer is damaged by a tool, preferably a spatula, scraper, knife, or wire, the tool preferably being inserted between the cover layer and the base body. [5] The method according to any one of [1] to [4], characterized in that when the cover layer is removed, the at least one adhesive layer is also removed at least partially, preferably completely. [6] The method according to [5], characterized in that the at least one adhesive layer is removed at least partially, preferably completely, after the cover layer has been removed. [7] The method according to [6], characterized in that, after the cover layer has been removed, a mechanical tool having or having a wire, spatula, scraper, blade, knife, or brush is used to remove the at least one adhesive layer. [8] The method according to any one of [1] to [7], characterized in that the conductor track is removed by brushing, milling, planing, shaping, scraping, chiseling, broaching, blasting and / or grinding. [9] The method according to any one of [1] to [8], characterized in that machined material is sucked up and collected in a container.

[10] Apparatus for carrying out the method described in any one of [1] to [9], comprising at least one heating device for heating the at least one adhesive layer, at least one traction device for applying tensile force, a mechanical removal device, and a collection device.

[11] The apparatus according to

[10] , wherein the traction device comprises at least one, preferably a plurality of, vacuum grippers.

[12] The apparatus according to

[10] or

[11] , wherein the apparatus comprises an electrical control unit, the removal device has at least one mechanical tool, and the electrical control unit is configured to control at least one operating parameter of the at least one mechanical tool.

[13] The apparatus according to

[12] , characterized in that the at least one operating parameter is contact pressure, path, or force.

Claims

1. A method for processing a solar module, wherein the solar module is A silicon-based body having an electric doping zone, a hole doping zone, and a top surface, The metal conductor track on the upper surface of the base body, A cover layer that is at least partially transparent to visible light, The system comprises at least one adhesive layer disposed between the cover layer and the conductor track, The aforementioned method, a) The step of heating at least one adhesive layer, b) The step of removing the cover layer from the base body, c) A method comprising the steps of mechanically removing the conductor track and collecting the machined material.

2. The method according to claim 1, characterized in that the adhesive layer is heated by infrared radiation and / or magnetic induction and / or microwave radiation to a temperature higher than 180°C and lower than 400°C.

3. The method according to claim 1, characterized in that the cover layer is removed from the base body by applying a force acting in opposite directions to the cover layer and the base body.

4. The method according to claim 1, characterized in that the cover layer is damaged by a tool before the cover layer is removed.

5. The method according to claim 1, characterized in that when the cover layer is removed, at least one adhesive layer is also removed at least partially.

6. The method according to claim 5, characterized in that the at least one adhesive layer is at least partially removed after the cover layer is removed.

7. The method according to claim 6, characterized in that, after the cover layer is removed, a mechanical tool is used to remove the at least one adhesive layer.

8. The method according to claim 1, characterized in that the conductor track is removed by brushing, milling, planing, shaping, scraping, chiseling, broaching, blasting and / or grinding.

9. The method according to claim 1, characterized in that machined material is sucked up and collected in a container.

10. An apparatus for carrying out the method according to any one of claims 1 to 9, comprising: at least one heating device for heating the at least one adhesive layer; at least one traction device for applying tensile force; a mechanical removal device; and a collection device.

11. The apparatus according to claim 10, characterized in that the traction device comprises at least one vacuum gripper.

12. The apparatus according to claim 10, characterized in that the apparatus comprises an electrical control unit, the removal apparatus has at least one mechanical tool, and the electrical control unit is configured to control at least one operating parameter of the at least one mechanical tool.

13. The apparatus according to claim 12, characterized in that the at least one operating parameter is contact pressure, path, or force.

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