SPACING DEVICE FOR A LAMINATING SYSTEM

Description

[0001] The present invention relates to a spacing device for a system for laminating a laminate, in particular photovoltaic modules, with a membrane, and to a method for producing such a spacing device. BACKGROUND

[0002] The production of photovoltaic modules involves the lamination of layers of a laminate (layer stack) under pressure and elevated temperature. The use of so-called membrane laminators is common for this lamination process. The lamination can be largely automated using a system that transports a large number of such laminates into a lamination chamber, in which a membrane clamped in a clamping frame is pressed onto the laminate to be laminated from above. At the same time, heat is applied to the laminate, and an exhaust system reduces the pressure around the laminate, which can increase or cause the pressure of the membrane.

[0003] Under the pressure of the membrane, whose surface area extends beyond that of the laminate, over-compression can occur in the edge areas of the laminate. This can lead to edge pinching, a reduction in thickness at the edge of the laminate. This can cause tensile forces within the laminate, which can cause delamination or, for example, breakage of a cover glass layer immediately after production or over time.

[0004] Fig. 6shows an illustration of how such edge pressing occurs. The left side of the figure shows a cross-section of a system for laminating a laminate 30. A membrane 210 is pressed onto the laminate 30 for lamination (e.g., by creating a suitable positive or negative air pressure). In membrane laminators, such a membrane 210 can, for example, have a thickness of up to 8 mm and an area on the order of several square meters. In the edge regions of the laminate 30, a surface of the membrane 210 projects beyond the laminate 30, whereby mechanical pressure exerted by the membrane 210 on the laminate 30 presses the laminate 30 more strongly there than in a central region of the laminate 30. This creates the edge pressing of the laminate. The right side of the figure shows an enlarged cross-section of the pressed edge region of the laminate 30.The laminate 30 here comprises two glass layers 33 arranged around a layer 37 comprising a plastic material and embedded solar cells. Glass layers can have thicknesses of up to 2.5 mm, for example, and the plastic layer can have a thickness in the range of one millimeter, so that the unpressed laminate 30 can have a thickness of, for example, 5 mm. Towards the edge of the laminate 30 (on the right side of the figure), the thickness of the laminate 30 is reduced due to the over-pressing. This causes persistent stress that limits the service life and quality of the photovoltaic modules.

[0005] A prior art device is known from document WO 2014 / 046810 A1.

[0006] There is a need for a cost-effective and efficient suppression of edge compression in membrane laminators, which is also advantageously suitable for retrofitting membrane laminators already in operation, so that existing automated processes can be maintained. BRIEF DESCRIPTION OF THE INVENTION

[0007] The above-mentioned object is achieved by a spacing device according to claim 1 and a method for producing a spacing device according to claim 11. The dependent claims relate to advantageous developments of the subject matter of the independent claims.

[0008] The present invention relates to a spacing device for a system for laminating a laminate, in particular photovoltaic modules. The system comprises a membrane holding device which is designed to apply a membrane to the laminate for lamination by exerting pressure. The spacing device has a circumferential belt, a plurality of spacing elements which are connected to the belt and are designed to at least partially form a frame for the laminate in at least one section of the belt and thereby suppress edge compression of the laminate during lamination, and at least one towing bar which is detachably connectable to the spacing elements and the at least partially formed frame is fastened to the at least one towing bar.

[0009] The membrane can be held in a tensioning frame that is lowered onto the laminate. The pressure on the laminate can be exerted indirectly, i.e., not through direct contact. In particular, during lamination, a sheet (a so-called "release sheet") can be placed between the membrane and the laminate to protect it and facilitate its detachment from the laminate after lamination. The surface of the membrane projects beyond a corresponding surface of the laminate, and the frame, partially formed by the spacer elements, supports the membrane next to the laminate in a manner suitable for reducing increased pressure in the edge region of the laminate, particularly due to the tension of the membrane.

[0010] The frame formed by the spacer elements can be only partial; in particular, it does not need to completely enclose the laminate. Supporting the membrane at certain suitable locations may be sufficient to reduce edge loading. Additionally—or alternatively—recesses in the frame may be required by the system's geometry. The frame can also be formed by combining spacer elements distributed across multiple strips.

[0011] The spacing elements are designed so that they can rotate with the belt. They can each be individually connected directly to the belt - for example, glued, welded, sewn or screwed on. In exemplary embodiments, the belt also has tow bars for its rotating movement, and the spacing elements can comprise an at least partially formed frame that is attached to one or more of the tow bars and rotates with the belt. For this purpose, the frame is advantageously designed to be flexible in the direction of rotation, but pressure-resistant and dimensionally stable vertically to the belt. This can be achieved, for example, by incorporating a suitable plastic material (such as rubber) or metal (such as chain belts), which forms the frame entirely or only partially.

[0012] Accordingly, the spacer elements can be made of either flexible material, such as silicone or Teflon materials or ethylene propylene diene rubber such as EPDM, or non-flexible material, such as aluminum or steel. Flexible materials can be used, in particular, to surround the spacer elements and can appear as continuous shapes, as bands, cords, and / or ropes, as segments with spaces between them, or in combination with non-flexible materials. Non-flexible materials can be used, for example, as chain straps, as zippers, or as rods, teeth, or support elements for the spacer elements.

[0013] Optionally, the lamination comprises forming a negative pressure, and the spacing elements are configured such that the formed frame has openings to promote the escape of gas from an area in or around the laminate during lamination.

[0014] For example, there are membrane lamination systems in which the pressure of the membrane on the laminate is at least partially generated by creating a negative pressure in the area around the laminate. Alternatively or additionally, evacuation around the laminate during lamination promotes the escape of air from the laminate. This can also serve, in particular, to prevent air or other gas inclusions in the laminate.

[0015] Optionally, during lamination, plastic is fused into the laminate, and the spacing elements are designed such that the formed frame has recesses or forms a gap to the laminate so that escaping plastic can be absorbed or removed during lamination.

[0016] A laminate for photovoltaic modules can, for example, comprise, among other things, a layer of a plastic material such as ethylene vinyl acetate (EVA) or polyolefin (PO) sandwiched between two glass plates, which encloses a plurality of photovoltaic cells and associated contacts. During lamination, such plastic material can escape laterally from the laminate between the glass plates. The spacing elements can be designed to enable and / or promote this escape of plastic material, for example by means of a suitable shape of a frame formed from the spacing elements. For example, the frame can have indentations, widened portions, grooves, channels and / or other recesses on a side facing the laminate, which provide sufficient space for escaping molten plastic material or encapsulation material.

[0017] Optionally, the membrane holding device is designed to apply the membrane to the laminate in a vertical movement, and the spacing elements are designed such that when the membrane is applied to the laminate, the formed frame is flush with the laminate.

[0018] The flush finish is intended to prevent excessive deflection of the membrane, as is the case with conventional systems. This can be achieved, for example, by ensuring that the spacer elements are the same height as the laminate to be produced and / or extend as close as possible to the laminate on at least one side facing the membrane.

[0019] The height of the spacer elements may also exceed the height of the laminate. This may be the case, in particular, if there is a gap between the laminate and the spacer elements when the membrane is pressed onto the laminate; for example, the spacer elements may protrude beyond the laminate by a few percent of the laminate's thickness. The height of the spacer elements may depend on the distance between the laminate and the spacer elements.

[0020] Optionally, the spacer elements comprise at least one of the following materials: steel, plastic, silicone, hard rubber, a base material with a non-stick coating.

[0021] Optionally, the spacer elements are interchangeably connected to the surrounding belt to form frames with a size and / or height adapted to different laminates.

[0022] For example, the circulating belt could be simply attached to brackets into which elements suitable for specific laminates can be inserted to form the spacer elements. If the spacer elements are connected to a tow bar of the belt, the connection to the tow bar can be detachable, allowing different spacer elements for different laminates to be connected to the tow bar.

[0023] Optionally, the circulating belt is a conveyor belt designed to place the laminate thereon and to transport it at least partially through the lamination system, or a release belt designed to lie between the membrane and the laminate during lamination and to promote detachment of the membrane from the laminate after lamination.

[0024] The conveyor belt or conveyor sheet can, in particular, comprise a material such as Teflon, which is suitable for easily lifting the laminate from the conveyor belt after lamination and preventing adhesion of material escaping from the laminate. Furthermore, the conveyor belt is advantageously sufficiently pressure- and heat-resistant to ensure its function as a support for the laminate during lamination. The release belt or release sheet can also be designed to protect the laminate.

[0025] Optionally, the spacing device comprises a release sheet as a circulating belt, to which spacing elements are applied, and a further circulating belt with further spacing elements, wherein the further circulating belt is a conveyor belt designed to transport the laminate for lamination. Furthermore, the further spacing elements of the conveyor belt can be designed to engage with at least some of the spacing elements during lamination, thus forming a continuous frame for the laminate, thereby suppressing edge compression of the laminate during lamination.

[0026] The term "continuous" refers specifically to a uniform frame height. For example, the spacer elements can be attached to the transport sheet located below the laminates, or to the release sheet located above the laminates. Likewise, part of the frame's assembly height can be applied to the transport sheet and the other part to the release sheet, so that the target frame height is achieved when both assembly heights overlap during the lamination process.

[0027] Optionally, the plurality of spacer elements comprises at least two spacer elements configured to interlock in a zipper-like manner during the formation of the at least partial frame during lamination.

[0028] The interlocking spacer elements can be attached to the same belt or to different belts.

[0029] Optionally, at least one of the spacer elements can have a chamfer to extend the service life of the membrane. Without chamfers, sharp edges of the spacer elements can cut into the membrane and thus damage it. Alternatively or additionally, the shape is also suitable for exerting a force in a horizontal direction toward the laminate, thereby reducing gaps between the spacer elements and the laminate to minimize air pockets (at least if the spacer elements have a certain degree of flexibility).

[0030] The present invention also relates to a method for producing a spacing device for a system for laminating a laminate, in particular a photovoltaic module. The system comprises a membrane holding device configured to apply a membrane for lamination to the laminate by exerting mechanical pressure. The method comprises the following steps: Providing a circumferential belt; attaching a plurality of spacer elements to the circumferential belt such that the spacer elements at least partially form a frame around the laminate during lamination and thereby suppress edge compression of the laminate during lamination when the membrane is applied to the laminate; releasably connecting at least one tow bar to the spacer elements, wherein the at least partially formed frame is attached to the at least one tow bar.

[0031] The spacing device is therefore intended, in particular, to prevent bending of the edge of the laminate during lamination by providing mechanical support provided by the spacing elements. The spacing elements support the membrane directly and / or indirectly (for example, in the case of a release sheet extending between the membrane and the spacing device) in a surface of the membrane that protrudes beyond the laminate, so that additional pressure exerted in the edge region of the laminate by the tension of the membrane is at least reduced.

[0032] Advantages of embodiments of a spacing device as described above include in particular the possibility of cost-effective production, which can simply be adapted to the geometry of an existing system for membrane lamination and can also be subsequently installed in such a system. BRIEF DESCRIPTION OF THE CHARACTERS

[0033] The embodiments of the present invention will be more fully understood from the following detailed description and the accompanying drawings, which, however, should not be construed to limit the disclosure to the specific embodiments, but are for explanation and understanding only. Fig. 1 shows a spacing device for a system for laminating a laminate. Fig. 2 shows two cross-sections of another exemplary embodiment of a spacing device for a system for laminating a laminate. Fig. 3 shows top views of two exemplary embodiments of the spacing device for a conveyor belt guided on towing bars. Fig. 4 shows a cross-section for a spacing device attached to towing bars. Fig. 5 shows further details of spacing elements in a cross-section of a system for laminating with a spacing device. Fig. 6 shows an illustration of the formation of edge pressing in a conventional system for laminating without a spacing device. Fig. 7 shows steps of a method for producing a spacing device for a system for laminating a laminate with a membrane. DETAILED DESCRIPTION

[0034] Fig. 1shows an embodiment of a spacing device 100 for a system for laminating a laminate 30, in particular photovoltaic modules. The system comprises a membrane holding device 200, which is designed to apply a membrane 210 to the laminate 30 for lamination under pressure. The spacing device 100 comprises a circulating belt 110 guided over deflection rollers and a plurality of spacing elements 120, which are connected to the belt and designed to form a frame 150 for the laminate 30 at least in a section of the circulating belt 110 and thereby suppress edge compression of the laminate 30 by the membrane 210 during lamination.

[0035] To avoid edge compression by the membrane 210, the active pressing surface of the membrane 210 should not be larger than the laminate 30 to be produced. This is achieved here by the plurality of spacer elements 120 that form frames 150 for the laminate 30. The frame 150 is advantageously only slightly larger than the outer edges of the laminate and has at least the height of the laminate 30 to be produced. The laminate 30 is advantageously placed in the lamination frame 150 before the start of the process. By protecting the frame 150 from over-compression of the edges by the membrane 210, laminates 30 can be produced without edge compression. The distance of the spacer elements 120 from the laminate 30 also depends on the deposition accuracy of the laminate 30 on the belt 110. The deposition accuracy varies between different laminating systems. In examples, the distance between laminate 30 and frame 150 may be in the order of 3 to 7 mm.The embodiment thus enables an automated process without manual handling and laminates 30 without edge pressing.

[0036] In the illustrated figure, the circulating belt 110 particularly transports the laminate 30 through at least parts of the lamination system. The laminates 30 are fed onto such a transport sheet and deposited before the start of the process. Designs in which a different belt 110 than the transport sheet is configured with spacing elements 120 are conceivable. In particular, several belts 110 can exist, the respective spacing elements 120 of which together form a frame 150 for the laminate 30 during lamination. For this purpose, the spacing elements 120 can also interlock with one another in the manner of a zipper.

[0037] In the figure shown, the spacer elements 120 are fixed to the belt 110. The spacer elements 120 can also be structures forming larger frames 150 that only need to be connected to the belt 110 at specific locations. The spacer elements 120 can be interchangeable, so that frames 150 for different laminates 30 can be formed using different spacer elements 120.

[0038] Fig. 2shows, arranged one above the other, two cross-sections through part of a lamination system with a membrane holding device 200 and a membrane 210, which is applied to a laminate 30 for lamination. The laminate 30 lies on a circulating conveyor belt or transport sheet 113 above a heating plate 300. A release belt 115, which also circulates, runs between the membrane 210 and the laminate 30 and protects the laminate 30 from contamination, for example, and facilitates lifting the membrane 210 from the laminate 30 after lamination. In lamination systems, a thickness of the release sheet 300 can be 0.3 mm, for example. Next to the laminate 30, spacer elements 120 are shown, which are intended to prevent the edges of the laminate 30 from being pressed over by the membrane 210. In the illustrated embodiment, the spacer elements 120 are attached to the sheets 113, 115 in the laminator.In this case, attachment to the transport sheet 113 located below the laminate 30 and / or to the release sheet 115 located above the laminate 30 is possible. The frame 150 formed by the spacer elements 120 can have openings positioned perpendicular to the laminate 30 and facilitate evacuation of an area around the laminates 30. Bevels 122 on the edges of the spacer elements 120 increase the service life of the membrane 210.

[0039] In the cross-section shown at the top of the figure, the membrane 210 is lowered onto the laminate 30 or onto the release sheet 115. The membrane 210 thereby closes off a laminate chamber around the laminate 30. In the lower cross-section, the arrows above the membrane 210 represent a pressure that presses the membrane 210 onto the release sheet 115 and laminate 30. The pressure can be generated or supported, for example, by an overpressure of a fluid (e.g., air) above the membrane 210, but also by an evacuation of air from the laminate chamber. During lamination, heat is supplied to the laminate 30 for lamination via a heating plate 300 shown below the transport sheet 113.

[0040] Fig. 3shows two top views, one above the other, each of an exemplary embodiment of the spacing device 100. In both parts of the figure, a top view of a section of a circulating conveyor belt 113 is shown, which is pulled through the lamination system via tow bars 117. In examples of membrane lamination systems, both a conveyor belt 113 and a release belt 115 (not shown here) are attached to such tow bars 117 and are guided by them through one or more laminate chambers or parts of the lamination system. The conveyor belt 113 can be continuous or interrupted; in particular, another section of the conveyor belt 113 can be adjacent to the right-hand side of the tow bar 117, or the conveyor belt 113 can be interrupted there.On the conveyor belt 113, the direction of rotation of which points, for example, in the direction of the right edge of the image, several laminates 30 lie in frames 150 formed from spacing elements 120.

[0041] In the upper part of the figure, the spacer elements 120 are attached directly to the conveyor belt 113. The frames 150 can also have spacer elements 120 made of stretchable or flexible, yet pressure-resistant material that extend in the transport direction, allowing the frames 150 to circulate.

[0042] In the lower part of the figure, the frames 150 for the individual laminates 30 are designed as a spacing element 120, which is not attached directly to the conveyor belt, but like the conveyor belt 113 to the towing bar 117 and is guided by it.

[0043] Fig. 4 shows a cross section for the embodiment in the lower part of the Figure 3. Visible are a lower tow bar 117 and an upper tow bar 118, for a direction of rotation pointing to the right in the image. A conveyor belt 113 is attached to the lower tow bar 117, and a release belt 115 to the upper tow bar 118. Both tow bars 117, 118 pull the belts 113, 115 through the lamination system. The belts 113, 115 can each be continuous or interrupted; in particular, another section of the respective belt 113, 115 can be adjacent to the right side of the tow bars 117, 118, or the respective belt 113, 115 can be interrupted there.

[0044] A spacing element 120 is also attached to the lower tow bar 117, which rests on the conveyor belt 113. The spacing element 120 can, for example, be screwed, welded, or clamped to the tow bar 117.

[0045] The spacer element 120 has frames 150 for one or more laminates 30 (not shown here). Alternatively, the spacer element 120 could also be attached to the tow bar 118 and pulled by it.

[0046] Fig. 5 shows further details of spacing elements 120 for an embodiment of the spacing device 100. Shown is a cross-section through a conveyor belt 113, a laminate 30 framed by spacing elements 120, and part of a membrane holding device 200. The spacing elements 120 are connected to the conveyor belt 113. They have a shape which is intended to allow material to escape from the laminate 30 during lamination. In particular, EVA, for example, can be removed from the plastic layer 37 (cf. Figure 6) escape from the laminate 30 during lamination. In the illustrated embodiment, the shape of the spacer elements 120 is the bevels 125. The spacer elements 120 reduce the outflow of encapsulation material because the laminate edges are not over-pressed. The risk of sticking is thereby already reduced or minimized. The spacer elements 120 are given a bevel to the laminate edge by the bevels 125 so that any encapsulation material flowing out has as little contact surface as possible with the spacer elements 120. Escaping material reaches the conveyor belt 113 through this shape. It is advantageous if the spacer elements 120, like the conveyor belt 113, have a non-stick coating made of material which prevents escaping material from sticking (such as Teflon).

[0047] In addition, the outer spacer elements 120 have bevels 122 that serve to protect the membrane 210 (not shown here) pressed on from above. Sharp edges can damage the membrane 210, whose thickness can be less than one centimeter; the bevels 122 allow the membrane 210 to conform over a larger area, thus increasing the service life of the membrane 210.

[0048] Fig. 7shows steps of a method for producing a spacing device 100 for a system for laminating a laminate 30, in particular a photovoltaic module, wherein the system comprises a membrane holding device 200 which is designed to apply a membrane 210 for lamination to the laminate 30 under the exertion of pressure. A first step comprises providing S100 a circumferential belt 110, which can be part of an existing system. A further step comprises attaching S200 a plurality of spacing elements 120 to the circumferential belt 110 in such a way that the spacing elements 120 at least partially form a frame 150 around the laminate 30 during lamination and thereby suppress edge compression of the laminate 30 during lamination when the membrane 210 is applied to the laminate 30.

[0049] The features of the invention disclosed in the description, the claims and the figures may be essential for the realization of the invention both individually and in any combination. LIST OF REFERENCE SYMBOLS

[0050] 30Laminate 100Spacing device 110Circular belt 113Transport belt (transport sheet) 115Release belt (release sheet) 117, 118Tow bars 120Spacing elements 122Bevel to increase membrane service life 125Recess to absorb escaping material 150Frame 200Membrane holding device 210Membrane 300Heating plate

Claims

1. A spacing device (100) for a system for laminating a laminate (30), in particular of photovoltaic modules, the system comprising a membrane holding mechanism (200) which is designed, for lamination, to apply a membrane (210) to the laminate (30) by exerting pressure, the spacing device (100) comprising: a circulating belt (110); a plurality of spacing elements (120) which are connected to the belt and designed to at least partially form a frame (150) for the laminate (30) in at least a portion of the circulating belt (110) and thereby suppress edge compression of the laminate (30) during lamination; characterized in that the spacing device comprises at least one tow bar (117, 118) which is detachably connectable to the spacing elements (120) and the at least partially formed frame (150) is fastened to the at least one tow bar (117, 118).

2. The spacing device (100) according to claim 1, wherein the lamination comprises forming a negative pressure, and wherein the spacing elements (120) are designed such that the formed frame (150) has openings to promote the escape of gas from a region in or around the laminate (30) during lamination.

3. The spacing device (100) according to either of the preceding claims, wherein during lamination, a fusion of plastics material in the laminate (30) takes place, and wherein the spacing elements (120) are designed such that the formed frame (150) has recesses (125) or forms a gap to the laminate (30) in order to accommodate escaping plastics material during lamination.

4. The spacing device (100) according to any of the preceding claims, wherein the membrane holding mechanism (200) is designed to apply the membrane (210) to the laminate (30) in a vertical movement, and wherein the spacing elements (120) are designed such that when the membrane (210) is applied to the laminate (30), the formed frame (150) is flush with the laminate (30).

5. The spacing device (100) according to any of the preceding claims, wherein the spacing elements (120) comprise at least one of the following materials: - steel, - plastics material, - silicone, - hard rubber, - a base material with a nonstick coating.

6. The spacing device (100) according to any of the preceding claims, wherein the spacing elements (110) are interchangeably connected to the circulating belt to form frames (150) which have a size and / or height adapted to different laminates.

7. The spacing device (100) according to any of the preceding claims, wherein the circulating belt (110) is one of the following: a conveyor belt (113) designed for the laminate (30) to be placed thereon and to transport it at least partly through the lamination system, a release belt (115) designed to lie between the membrane (210) and the laminate (30) during lamination and to promote detachment of the membrane (210) from the laminate (30) after lamination.

8. The spacing device (100) according to any of claims 1 to 6, wherein the circulating belt (110) is a release belt (115) which is designed to lie between the membrane (210) and the laminate (30) during lamination and to promote detachment of the membrane (210) from the laminate (30) after lamination; and wherein the spacing device (100) further comprises the following: a further circulating belt with further spacing elements, wherein the further circulating belt is a conveyor belt (113) designed to transport the laminate (30) for lamination, and the further spacing elements are designed to engage with at least some of the spacing elements (120) during lamination to form a stepless frame (150) for the laminate (30) and thereby suppress edge compression of the laminate (30) during lamination.

9. The spacing device (100) according to claim 8, wherein the plurality of spacing elements (120) comprises at least two spacing elements which are designed to engage in a zip-like manner with each other upon formation of the at least partial frame (150) during lamination.

10. The spacing device (100) according to any of the preceding claims, wherein at least one of the spacing elements (120) has a bevel (122) in order to extend a service life of the membrane (210) and / or is suitable for building up a pressure in the direction of the laminate (30) when the membrane (210) is applied to the laminate (30) by the mechanical pressure exerted on the spacing element via the membrane (210).

11. A method for producing a spacing device (100) for a system for laminating a laminate (30), in particular of a photovoltaic module, the system comprising a membrane holding mechanism (200) which is designed to apply a membrane (210) for lamination to the laminate (30) by exerting mechanical pressure, the method comprising the following steps: providing (S100) a circulating belt (110); fastening (S200) a plurality of spacing elements (120) to the circulating belt (110) such that the spacing elements (120) at least partially form a frame (150) around the laminate (30) during lamination and thereby suppress edge compression of the laminate (30) during lamination when the membrane (210) is applied to the laminate (30); characterized in that the method comprises detachably connecting at least one tow bar (117, 118) to the spacing elements (120), the at least partially formed frame (150) being fastened to the at least one tow bar (117, 118).