Frame profile for a solar module

Abstract

Frame profile (1) made of cold-formed steel strip for receiving a photovoltaic laminate, comprising - a frame groove (3) for inserting the laminate, - a hollow chamber (5) for torsional stiffening and - at least one frame leg (7), characterized by the fact that at least one free sheet metal end (9, 11) is arranged outside the frame groove (3) and directed downwards, optionally (a) the two free sheet metal ends (9, 11) on the top (13) or on the bottom (15) of the frame profile (1) are connected to each other by a folded or hemmed joint (17) whose fold faces downwards, and / or (b) a downwardly projecting flange of the steel strip is formed on the underside (15) of the frame profile (1).

Description

[0001] The present invention relates to a frame profile made of cold-formed steel strip for framing photovoltaic laminates.

[0002] Photovoltaic modules are exposed to the elements throughout their entire lifespan – typically more than 25 years – including rain, snow, UV radiation, salt spray, and widely fluctuating temperatures. To protect the sensitive laminate structure of glass, encapsulation film, and solar cells from mechanical and corrosive stresses, it is usually enclosed by a surrounding frame.

[0003] Aluminum profiles are a well-known and established solution from the state of the art. However, they incur high material costs and are no longer the preferred option due to their energy efficiency.

[0004] Using steel as the basis for the profiles offers a more economical and environmentally friendly alternative, but requires a design that ensures corrosion protection, maintains torsional stiffness and is compatible with existing manufacturing and assembly systems.

[0005] According to the known state of the art, in such steel profiles the two open ends of the formed steel strip are joined together in the frame groove. This means that the unprotected butt joint lies directly within the area of ​​the silicone sealant; any moisture or condensation that penetrates can accelerate corrosion, which consequently has a negative impact on the durability of the frame.

[0006] Newer variants, in accordance with the state of the art, do provide vertical bending legs on the back of the frame, but do not satisfactorily solve the problem of the joint located within the groove.

[0007] There is also considerable potential for improvement in the torsional stiffness of frame profiles according to the state of the art.

[0008] Furthermore, it would be advantageous if the frame profiles had a geometry that functions well in and can be integrated into increasingly automated production and logistics systems.

[0009] The object of the present invention is therefore to provide a steel frame profile in which the susceptibility to corrosion in the area of ​​the groove is significantly reduced, which at the same time has high torsional and bending stiffness, offers a clear stacking or gripping contour for automated process steps or can be incorporated into existing module and tracker lines without costly retrofit measures.

[0010] This problem is solved by a frame profile made of cold-formed steel strip for receiving a photovoltaic laminate, comprising a frame groove for inserting the laminate, a hollow chamber for torsional stiffening and at least one frame leg, wherein at least one free sheet end is arranged outside the frame groove and directed downwards, wherein optionally (a) the two free sheet ends are connected to each other on the top or bottom of the frame profile by a folded or hemming connection, the folded edge of which points downwards, and / or (b) a downwardly projecting flange is formed on the bottom of the frame profile from the steel strip.

[0011] The frame profile according to the invention is divided – like conventional aluminum frames according to the prior art – into three basic functional zones. The frame groove defines a U-shaped receiving channel for the laminate and the surrounding silicone sealant. Due to its closed cross-section, the hollow chamber gives the profile high torsional stiffness without significantly increasing material consumption compared to a solid cross-section. The at least one frame leg forms the static base of the profile and simultaneously provides the connection surface for fastening or transport aids.

[0012] The core of the invention lies in relocating at least one open sheet metal end from the groove to an external, downward-facing area. This creates a drip edge from which rainwater and condensation can run off in a controlled manner, so that neither the silicone seal nor the bare cut metal is exposed to moisture.

[0013] In a first embodiment, both sheet metal ends are joined together either on the top or bottom by a so-called hemming connection – a double folded seam – in a form-fitting and force-fit manner. The folded pocket is directed downwards to further promote water drainage.

[0014] In the second embodiment of the invention, as an alternative to the Hemming connection, the formed steel strip on the underside of the frame forms a downwardly projecting flange. This extended leg does not serve to connect the edges, but rather creates a defined stop and gripping contour, ensuring that stacked modules lie reproducibly on top of each other and that automatic gripping systems have a clearly dimensioned contact surface.

[0015] According to the present invention, it is naturally provided that instead of the flange, a hemming connection formed on the underside according to the invention forms this stop or gripping contour.

[0016] Both embodiments share the same basic inventive idea: the critical impact or cutting edge is led out of the laminate bed and placed in a zone where it is protected from standing moisture.

[0017] This eliminates the main risk of corrosion, and the silicone seal remains completely closed. The hollow chamber construction ensures that the steel profile, despite its slim geometry, achieves a rigidity comparable to aluminum frames.

[0018] Furthermore, the downward-facing flange or the hemming connection located on the underside optimizes the profile for automated manufacturing and logistics processes.

[0019] The frame profile according to the invention thus solves the problem set and meets the high static and corrosive requirements of the years- to decades-long open-field use of solar modules, while being more cost-effective than aluminum profiles and seamlessly integrating into existing production and assembly systems.

[0020] In a further advantageous embodiment, the downwardly directed section—be it the flange according to alternative (b) or the downwardly oriented hemming connection according to alternative (a)—projects by at least n millimeters, wherein n is preferably 3, 4, 5, 6, 8, 9 or 10 mm, but in particular less than 20 mm, below the underside 15 of the frame profile 1.

[0021] This defined overhang length fulfills two interlocking functions. Firstly, it forms a mechanically robust stacking stop: When several frames are stacked on top of each other, the protruding section engages positively with the top edge of the profile below, preventing the sensitive frame groove or the modular glass layer from becoming load-bearing surfaces.

[0022] Secondly, the resulting gap provides a reproducible gripping edge for automated logistics and assembly systems. Gripper jaws, vacuum suction cups, or conveyor chains find a precise point of contact on the defined overhang to move, stack, etc., the frame modules. Additionally, the overhang can be used for the automatic alignment and fastening of the modules to the substructure.

[0023] The choice of the inventive interval for the downward projection of 3 to 20 mm ensures that the stop offers sufficient leeway for different frame thicknesses and manufacturing tolerances, while remaining compact enough not to adversely affect either the aerodynamic behavior of the mounted module or the packaging volume for transport. A projection of less than 20 mm also ensures that the profile remains compatible with common clamp and back-rail systems without requiring special adapters.

[0024] According to the invention, it may be preferred that the folding or hemming connection is made double-folded, so that a double-fold zone is created.

[0025] In this preferred embodiment of the present invention, the folded or hemming joint is executed as a double fold. The first, inner sheet end remains essentially in its rolling plane, while the second, outer sheet end is first brought approximately ninety degrees towards the inner sheet end in a pre-fold and then folded over a further ninety degrees beyond it in a final fold until its cut edge disappears completely into the resulting fold pocket.

[0026] The result of these folds is a three-layer lamella package, the outermost layer of which lies flat against the middle and inner layers, creating a closed double-fold zone without exposed cut edges.

[0027] The triple material thickness in the fold area increases the local bending and torsional stiffness of the frame profile without requiring additional components or welds. Furthermore, the protected position of the cut edges within the double-fold zone minimizes the risk of crevice or contact corrosion and enables a homogeneous coating of the outer component in the cases provided for according to the invention.

[0028] The double hemming fold can be realized in a continuous roll forming process in two successive forming stations, wherein the end fold is preferably fixed inline by roller pressing, resistance spot welding or laser beam according to an embodiment of the invention, so that a process-technically robust and economical production is ensured.

[0029] According to a further embodiment of the present invention, it can be provided that the frame groove is arranged laterally offset to the hollow chamber in cross-sectional view.

[0030] In a particularly preferred embodiment, the frame groove is not located directly above the hollow chamber, but to the side of it. The offset between the outer vertical walls between the frame groove and the hollow chamber can be between 2 and 12 mm.

[0031] This offset arrangement ensures that the laminate pressure and adhesive forces occurring in the groove are no longer transmitted perpendicularly into the vertical chamber walls, but are transferred via a stepped web into the surrounding profile. This reduces the risk of local stress concentrations and associated glass damage at the module edge; furthermore, the hollow chamber geometry remains undeformed, thus fully preserving its torsional stiffness.

[0032] The offset also creates constructive space for insertion aids and allows for independently optimized wall thicknesses of the groove and chamber areas without increasing the overall height of the profile. Thus, the laterally offset layout contributes to both the mechanical robustness and the ease of manufacturing of the frame profile.

[0033] Furthermore, it may be preferred that at least one wall of the hollow chamber is designed with recesses and projections in order to increase its bending stiffness.

[0034] In this variant, the hollow chamber no longer has a continuously flat or vertical wall. Its contour is enhanced by targeted projections and recesses. Such stepped wall segments increase the area moment of inertia without the use of additional material, thus increasing the bending and torsional stiffness of the entire profile.

[0035] At the same time, the steps interrupt the free propagation of buckling waves and result in a more uniform stress distribution under wind and snow loads. The recesses and projections can be produced inline during roll forming, eliminating the need for downstream welding or joining processes. This achieves a higher level of stiffness without significantly increasing material consumption or the cycle time of profile production.

[0036] In particular, it may be provided that the recesses and projections on the opposite walls of the hollow chamber are symmetrical to each other.

[0037] A mirror-image arrangement of the aforementioned steps on both side walls of the hollow chamber results in a load-symmetrical structure that absorbs torsional and bending forces identically in both principal directions. This symmetrical design prevents the frame from twisting under unilateral temperature or load effects and minimizes variations in deflection, which is particularly advantageous for large-format glass-to-glass modules. Furthermore, the mirror-symmetrical design simplifies tooling design, as both wall sides can be manufactured with identical rolling or stamping inserts, reducing wear and increasing process stability.

[0038] Further features and advantages of the invention are shown with reference to the following figures, which illustrate embodiments of the invention. The following are depicted: Fig. 1: a sectional view of a first embodiment of a frame module according to the invention; Fig. 2: a sectional view of a second embodiment of a frame module according to the invention; and Fig. 3: a sectional view of a third embodiment of a frame module according to the invention.

[0039] Fig. Figure 1 shows a cross-sectional embodiment of a frame profile 1 according to the invention, made of cold-formed steel strip. On the side facing the photovoltaic laminate, there is a U-shaped frame groove 3, which can accommodate the glass-foil-cell composite (not shown) and simultaneously provides space for a circumferential silicone seal. Below this is a hollow chamber 5, the circumferential wall of which makes the profile torsionally and flexurally resistant without reaching the weight of a solid cross-section.

[0040] Below the hollow chamber 5, a frame leg 7 extends as a static base. The two free sheet metal ends of the steel strip are labeled 9 (inner end) and 11 (outer end). In the Fig. In the variant shown in 1, these ends are joined on the upper side 13 of the profile by a downward-facing, double-folded hemming connection 17 in a form-fit and force-fit manner, so that their cut edges lie in a folded pocket facing away from the water.

[0041] This shows that the hemming connection 17 is located on the top 13 directly below the frame groove 3.

[0042] In Fig. Figure 2 shows a variant of an embodiment according to the invention, in which the hollow chamber 5 is shown, in which it has symmetrical bulges to increase stability.

[0043] In the alternative version according to Fig. 3 the Hemming connection 17' is located on the underside 15; alternatively, a flange not shown, projecting below the profile edge, can also be formed there.

[0044] The hemming connection, or the not shown fold, protrudes a few millimeters below the underside 15 and thus serves as a defined stacking and gripping stop for automated logistics and assembly processes, while the outward displacement of the butt joint protects the silicone seal in the frame groove from moisture and corrosion.

Claims

[1] Frame profile (1) made of cold-formed steel strip for receiving a photovoltaic laminate, comprising - a frame groove (3) for inserting the laminate, - a hollow chamber (5) for torsional stiffening and - at least one frame leg (7), characterized by , that at least one free sheet metal end (9, 11) is arranged outside the frame groove (3) and directed downwards, optionally (a) the two free sheet metal ends (9, 11) on the top (13) or on the bottom (15) of the frame profile (1) are connected to each other by a folded or hemmed joint (17) whose fold faces downwards, and / or (b) a downwardly projecting flange of the steel strip is formed on the underside (15) of the frame profile (1). [2] Frame profile according to claim 1, characterized by, that the hemming connection (17') connecting the two free sheet metal ends (9, 11) is arranged projecting downwards on the underside (15) of the frame profile (1). [3] Frame profile according to claim 1 or claim 2, characterized by , that the flange and / or the hemming connection (17') projecting downwards on the underside (15) projects at least n millimeters, with n = 3, 4, 5, 6, 8, 9, 10 or more and in particular less than 20 mm below the underside (15) of the frame profile (1) and serves as a stacking stop. [4] Frame profile according to one of the preceding claims, characterized by , that the folding or hemming connection (17) is double-folded, creating a double-fold zone. [5] Frame profile according to one of the preceding claims, characterized by , that the frame groove (3) is arranged laterally offset to the hollow chamber (5) in cross-sectional view. [6] Frame profile according to one of the preceding claims, characterized by, that at least one wall of the hollow chamber (5) is designed with recesses and projections to increase its bending stiffness. [7] Frame profile according to claim 6, characterized by , that the recesses and projections on the opposite walls of the hollow chamber (5) are symmetrical to each other. [8] Photovoltaic module with a frame profile according to one of claims 1 to 7, characterized by , that the laminate is glued in a sealing manner into the frame groove (3) which is arranged laterally offset to the hollow chamber (5). [9] Use of the frame profile according to any one of claims 1 to 8 as a mechanical stacking and gripping stop in an automated conveying or assembly device, in which the flange or hemming segment (19; 17') projecting below the underside (15) can be used as a support or engagement edge for the automatic alignment and fastening of the modules on the substructure.

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