A support-free frameless waterproof BIPV roof system and construction method

Abstract

This invention discloses a prefabricated, frameless, waterproof BIPV roofing system and its construction method, comprising: roof purlins; self-locking profiled metal sheets fixed above the roof purlins; frameless photovoltaic glass directly laid on top of the profiled metal sheets; a fixing support, its bottom fixed to the roof purlins, its top connected to the profiled metal sheets and supporting the edges of the frameless photovoltaic glass; a connecting groove, an integral structure, located at the joint between two adjacent frameless photovoltaic glass panels, used to connect and seal the joint along the roof slope; and a fixing cap, which is pressed onto the fixing support and presses the edges of the frameless photovoltaic glass tightly and securely. This invention adopts a prefabricated lightweight design, deeply integrating photovoltaic modules with the roof structure, simplifying the on-site construction process, improving construction efficiency, and simultaneously reducing the overall weight of the roof and the load-bearing pressure on the main roof structure.

Description

Technical Field

[0001] This invention belongs to the field of building-integrated photovoltaics (BIPV) technology, specifically relating to a prefabricated frameless, frameless, waterproof BIPV roofing system and its construction method. Background Technology

[0002] Building-integrated photovoltaics (BIPV) roofing systems are green building photovoltaic application systems that integrate the design, production, and construction of photovoltaic modules with building roofs. They are not simply adding photovoltaic modules to the roof as in traditional methods. Instead, they replace traditional roofing materials such as corrugated steel tiles, glazed tiles, and roof rolls with photovoltaic modules. The photovoltaic modules convert solar energy into clean electricity and can be adapted to the roofing needs of different building types, such as industrial plants, commercial complexes, and residential buildings. They can effectively reduce building energy consumption and improve the low-carbon level of buildings.

[0003] The existing water guide brackets of building-integrated photovoltaic (BIPV) roofing systems are installed by drilling, which damages the original waterproof layer of the roof and is not reliable enough in rainy weather, leading to long-term leakage risks. In addition, the frames of the framed photovoltaic glass modules are higher than the glass surface, making the power-generating glass suspended. In rainy weather, the glass is prone to deformation, and dust accumulation can lead to hot spots and microcracks in the glass, which seriously shortens the life of the modules and directly affects the photovoltaic power generation efficiency, while increasing the daily cleaning and maintenance costs. Summary of the Invention

[0004] The purpose of this invention is to propose a prefabricated, frameless, waterproof BIPV roofing system and construction method to solve the problems in the prior art.

[0005] Therefore, the present invention provides a prefabricated, frameless, waterproof BIPV roofing system, including roof purlins, and further comprising: Self-locking edge profiled metal sheet, the self-locking edge profiled metal sheet is fixed above the roof purlin; The frameless photovoltaic glass is laid directly on top of the profiled metal sheet. The photovoltaic cells are encapsulated using co-extruded POE modified encapsulating film. Fluorine-modified butyl rubber sealing tape is set around the edges of the frameless photovoltaic glass. The frameless photovoltaic glass constitutes the first waterproof layer and power generation layer of the roof, and the profiled metal sheet constitutes the second waterproof layer and structural support layer of the roof. A fixed support member, the bottom of which is fixed to the roof purlin, and the top of which is connected to the profiled metal sheet and supports the edge of the frameless photovoltaic glass; The connecting groove is an integral structure and is set at the joint of two adjacent frameless photovoltaic glass pieces to connect and seal the joint along the roof slope. The fixing cap is pressed onto the fixing support and the edge of the frameless photovoltaic glass is pressed and fixed.

[0006] In some embodiments, the co-extruded POE modified encapsulating film has a main substrate made of co-extruded polyolefin elastomer (POE), a core layer with 0.6%-1.0% hydrolysis stabilizer, 0.4%-0.7% hindered amine light stabilizer, and 0.2%-0.4% silane coupling agent, and a surface layer modified with low molecular weight fluorinated hydrophobic agent.

[0007] In some embodiments, the anti-hydrolysis stabilizer is selected from one or more of carbodiimides, isocyanates, oxazoline compounds, or epoxy compounds; the hindered amine light stabilizer is a tetramethylpiperidine derivative.

[0008] In some embodiments, the fluorinated butyl rubber sealing tape has a main body of butyl rubber modified with 10%-15% polytetrafluoroethylene micro powder, and the tape surface is coated with a 1-2μm nano-silica hydrophobic coating with a surface hydrophobic angle ≥110°.

[0009] In some embodiments, the frameless photovoltaic glass is provided with a U-shaped enclosing sealing layer around its four edges.

[0010] In some embodiments, the connecting groove is an H-shaped connecting groove, including an upper groove and a lower groove, wherein the upper groove and the lower groove are respectively snapped into the upper and lower side edges of the frameless photovoltaic glass; The upper groove is pre-bonded to the edge of the photovoltaic glass using sealant, and the lower groove is sealed to the edge of the other photovoltaic glass using a waterproof strip.

[0011] In some embodiments, waterproof strips are provided between the self-locking edge-formed metal plate and the frameless photovoltaic glass, and between the fixed cover and the frameless photovoltaic glass.

[0012] In some embodiments, the self-locking edge-formed metal sheet includes a sheet body; The main body of the plate is provided with self-locking edge protrusions at intervals, and glass support protrusions are provided between adjacent self-locking edge protrusions. The edge of the main body of the plate is provided with overlapping protrusions. The self-locking edge protrusion, the glass support protrusion, and the overlapping protrusion are all continuous structures formed along the width direction of the self-locking edge profiled metal sheet.

[0013] In some embodiments, the self-locking edge protrusion includes a rectangular protrusion, the top of which is provided with an arc-shaped protrusion, and the top of the arc-shaped protrusion is engaged with the fixing cap. The area enclosed by the fixing cap, the arc-shaped protrusion, and the rectangular protrusion is used to fix the frameless photovoltaic glass. The self-locking edge protrusion has a hollow structure, and the top of the fixing support passes through the hollow structure and interlocks with the interior of the arc-shaped protrusion.

[0014] In some embodiments, a ventilation and cooling device is also included, which is installed between adjacent frameless photovoltaic glass and connects the air layer between the frameless photovoltaic glass and the profiled metal plate with the outside atmosphere. The breathable cooling device includes tempered glass, and multiple vent caps are formed on the surface of the tempered glass along its length. The tempered glass is connected to the adjacent frameless photovoltaic glass via the connecting groove.

[0015] In some embodiments, at least one layer of insulation board is provided below the self-locking edge-formed metal sheet, and the insulation board is connected to a support base fixed to the roof purlin; A vapor barrier layer is provided below the insulation board, and the vapor barrier layer is fixed to the support base.

[0016] On the other hand, a construction method for a prefabricated frameless waterproof BIPV roofing system based on any of the above-mentioned methods is also provided, comprising the following steps: Install fixed support bases and fixed support components on the roof purlins; A vapor barrier and insulation board are laid sequentially above the roof purlins; Install the profiled metal sheet and connect the profiled metal sheet to the fixed support member; The edges of the frameless photovoltaic glass are coated with sealant and pre-installed with metal clips to form an integrated module. The pre-assembled integrated components are transported to the site and laid on top of the profiled metal sheet along the roof slope, so that adjacent components are connected to each other through the H-shaped connecting groove. Install the fixing cap to press and fix the edge of the frameless photovoltaic glass onto the fixing support.

[0017] In some embodiments, the thickness of the sealant layer applied by the automatic glue applicator is 1.5±0.2mm, and the hardness of the sealant after curing is ≥80 Shore A.

[0018] Beneficial effects: 1. This invention uses frameless photovoltaic glass as the first waterproof layer on the roof and a self-locking edge-pressed metal plate as the second waterproof layer, abandoning the traditional practice of using a metal plate as the first waterproof layer. This solves the problems of the inherent inadequacy of waterproof performance in traditional BAPV and BIPV systems and the easy penetration of rainwater into the surface of the metal plate, leading to corrosion and aging. It achieves the effect of blocking rainwater and sand erosion from the source, significantly delaying the rusting and aging of the metal plate, and extending the service life of the metal plate to match the entire life cycle of the photovoltaic module.

[0019] 2. This invention, by adopting frameless power-generating glass and prefabricated lightweight design, eliminates the traditional brackets and component frames, solving the problems of high material input, high construction cost, cumbersome procedures, and large additional load on the roof in existing systems. It achieves the effects of reducing the self-weight of the roof, reducing the initial investment and installation cost, and improving construction efficiency.

[0020] 3. This invention solves the problems of lack of protection measures for the roof color steel plate and connectors and easy damage to the roof structure caused by the existing construction process by adopting a prefabricated construction process of automated glue application and pre-assembly of frameless power-generating glass and H-shaped connecting grooves in the factory and rapid on-site corrugated splicing. It achieves the effects of ensuring the sealing quality of the connection nodes, simplifying the on-site construction process and shortening the construction cycle.

[0021] 4. This invention solves the problems of loose connection nodes and sealing failure leading to rainwater and dust intrusion by using water-blocking flexible connecting strips embedded between the self-locking edge profiled steel plate and the frameless power-generating glass, as well as between the fixing cover and the glass, and by using the fixing cover to fasten it. This achieves the effect of enhancing the overall wind resistance of the roof, preventing rainwater penetration, and ensuring the long-term reliability of the connection nodes.

[0022] 5. This invention optimizes the overall structure of the roof surface by using frameless photovoltaic glass, reduces dust accumulation dead corners, and achieves self-cleaning with natural rainwater rinsing. This solves the problem of easy dust accumulation on the surface of photovoltaic modules, which leads to a significant reduction in power generation efficiency and high maintenance costs. It achieves the effects of ensuring the light transmittance of photovoltaic modules, stabilizing power generation efficiency, and reducing manual cleaning and maintenance costs.

[0023] 6. This invention encapsulates frameless power-generating glass with a co-extruded POE modified encapsulating film and sets fluorine-modified butyl rubber sealing tape around the edges of the glass to form a double U-shaped sealing layer. This solves the problems of insufficient hydrolysis resistance and water-blocking ability of traditional EVA encapsulating films, easy water seepage at the gaps in the frame that can cause short circuits and fires in the modules. It achieves the effect of significantly improving the water-proof ability of the modules, blocking the water vapor penetration path with double sealing, and meeting the mechanical protection requirements during handling.

[0024] 7. This invention uses frameless photovoltaic glass as the first waterproof layer, allowing it to directly withstand rainwater erosion and protect the metal panel below. This solves the problem of a serious mismatch between the designed service life of the roof metal panel and the service life of the photovoltaic module, which leads to huge costs for secondary replacement and maintenance. It achieves the effect of eliminating the cost of secondary replacement and maintenance and realizing the same lifespan for the roof system and the photovoltaic module.

[0025] 8. This invention solves the problems of high airflow resistance on long-sloped roofs and excessively high photovoltaic glass back panel temperature affecting power generation efficiency by setting a breathable cooling device between the components, connecting the air layer between the photovoltaic glass and the metal plate with the outside atmosphere. It achieves the effects of breaking the airflow boundary layer, enhancing ventilation, and reducing the temperature of the photovoltaic glass back panel in a large area.

[0026] 9. This invention, by setting a vapor barrier layer under the insulation layer and an insulation board under the metal plate, forms a dual structure of vapor barrier and insulation, which solves the problem of indoor humid hot water vapor penetrating upward into the insulation layer, causing condensation and deterioration of the insulation material's performance due to moisture. It achieves the effects of eliminating condensation, maintaining stable thermal insulation performance, delaying steel corrosion, and extending the overall service life of the roof structure. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the frameless photovoltaic glass structure.

[0029] Figure 2 This is a schematic diagram showing the connection between the mounting groove and the frameless photovoltaic glass.

[0030] Figure 3 This is a schematic diagram of a self-locking edge-formed metal sheet.

[0031] Figure 4 This is a schematic diagram of a fixed support component.

[0032] Figure 5 This is a three-dimensional view of the fixed support component.

[0033] Figure 6 This is a schematic diagram of the supporting base.

[0034] Figure 7 This is a schematic diagram of a ventilation and cooling device.

[0035] Figure 8Cross-sectional view of the air-permeable cooling device Figure 9 This is a diagram illustrating two types of waterproof leather strips.

[0036] Figure 10 This is a schematic diagram of a fixed pressure cap.

[0037] Figure 11 This is a partial schematic cross-sectional view of the system after assembly.

[0038] Figure 12 This is a schematic diagram of installing profiled steel sheet seam brackets and support bases on existing roof purlins.

[0039] Figure 13 This is a schematic diagram of the installation of an air-barrier vapor barrier.

[0040] Figure 14 This is a schematic diagram for installing insulation boards.

[0041] Figure 15 This is a schematic diagram for installing the fixed support components.

[0042] Figure 16 This is a schematic diagram for installing a self-locking edge-formed metal sheet.

[0043] Figure 17 A schematic diagram for installing frameless photovoltaic glass.

[0044] Figure 18 This is a schematic diagram for installing the fixing cover.

[0045] In the diagram: 1. Roof purlin; 2. Self-locking profiled metal sheet; 201. Main body of the sheet; 202. Self-locking protrusion; 2021. Self-locking protrusion; 2022. Arc-shaped protrusion; 203. Glass support protrusion; 204. Overlap protrusion; 3. Frameless photovoltaic glass; 4. Edge sealing tape; 5. U-shaped enclosing sealing layer; 6. Fixing support; 7. Connecting groove; 701. Upper groove; 702. Lower groove; 8. Fixing cap; 9. Sealant; 10. Waterproof strip; 11. Ventilation and cooling device; 1101. Tempered glass; 1102. Ventilation cap; 12. Insulation board; 13. Vapor barrier; 14. Self-tapping screw; 15. Support base. Detailed Implementation

[0046] The invention will be more readily understood by referring to the following detailed description of preferred embodiments and included examples. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the definitions in this specification shall prevail.

[0047] like Figures 1-11As shown, a prefabricated frameless waterproof BIPV roofing system includes a roof purlin 1, a self-locking edge-formed metal sheet 2, frameless photovoltaic glass 3, a fixing support 6, a connecting groove 7, and a fixing cap 8.

[0048] Roof purlins 1 are the main load-bearing components of the roof and are pre-installed on the steel structure of the newly built factory. Self-locking profiled metal sheets 2 are fixed above the roof purlins 1. These sheets are manufactured using a high-strength corrugated forming process, with self-locking edges that allow for quick overlap with adjacent sheets to form a unified roof. Custom-made to the dimensions of the frameless photovoltaic glass 3, these sheets are constructed from thermally insulated metal sheets with a uniformly distributed corrugated surface. This structure ensures the structural strength of the substrate, enhances the roof's wind resistance, and provides a flat and stable mounting surface for the frameless photovoltaic glass 3. In this system, the self-locking profiled metal sheet 2 serves as the second waterproofing layer and structural support layer for the roof.

[0049] The frameless photovoltaic glass 3 is directly laid on top of the self-locking edge-formed metal plate 2. The frameless photovoltaic glass 3 uses co-extruded POE modified encapsulating film to encapsulate the photovoltaic cells, and its four edges are sealed with fluorine-modified butyl rubber edge-sealing tape 4. In the system, the frameless photovoltaic glass 3 serves as the first waterproof layer and power generation layer of the roof. Made of tempered photovoltaic glass, its dimensions precisely match the self-locking edge-formed metal plate 2. The frameless structure design significantly reduces the roof's self-weight, eliminating the unnecessary load and installation inconvenience of traditional frames. The frameless photovoltaic glass 3 possesses both high-efficiency photovoltaic power generation capabilities and, as the first waterproof layer of the roof, forms a double-layer waterproof system with the self-locking edge-formed metal plate 2. This effectively prevents rainwater and dust from eroding the self-locking edge-formed metal plate 2, delaying corrosion and aging, and extending its service life. Meanwhile, the frameless photovoltaic glass 3, supported by the self-locking edge-formed metal plate 2 below, can be stepped on and walked on by workers, thus serving as a roof maintenance passage.

[0050] The bottom of the fixed support member 6 is fixed to the roof purlin 1, and the top of the fixed support member 6 is connected to the self-locking edge-formed metal plate 2 and supports the edge of the frameless photovoltaic glass 3. The fixed support member 6 is a continuous component, which is fastened to the roof purlin 1 with self-tapping screws 14 or through bolts using the fixed support base 15. Its top is fixed to the self-locking edge-formed metal plate 2 with a self-locking connection, which can form a stable support for the self-locking edge-formed metal plate 2. This component can provide reliable anchoring for the overall roof system and photovoltaic modules, ensuring the overall coordination and load-bearing stability of the photovoltaic system and the roof structure.

[0051] The connecting groove 7 is an integral structure, located at the joint between two adjacent frameless photovoltaic glass panels 3, used to connect and seal the joint along the roof slope. The connecting groove 7 is mainly used to connect and connect two adjacent photovoltaic modules on a pitched roof, enabling rapid assembly and connection between the photovoltaic glass panels. It ensures smooth drainage at the splicing location, neat and uniform joints, and structural stability, effectively reducing on-site construction procedures and improving installation efficiency, while also protecting the frameless photovoltaic glass 3. Furthermore, based on the slope of the roof, the connection groove 7, in conjunction with the frameless photovoltaic glass 3, forms a self-waterproof slope with a downward tilt angle ≥5°, utilizing gravity to naturally guide rainwater.

[0052] The fixing cap 8 is pressed onto the fixing support 6, and the edges of the frameless photovoltaic glass 3 are pressed and fixed. The fixing cap 8 is mainly used to fix the frameless photovoltaic glass 3, protect the frameless photovoltaic glass 3, and play a waterproof role. It enhances the mechanical stability and waterproof sealing of the connection node and effectively blocks the path of rainwater seepage from the connection gap.

[0053] The aforementioned components work together to form a complete BIPV roofing system. The frameless photovoltaic glass 3, acting as the first waterproofing layer, directly withstands rainwater runoff and guides it out. The self-locking edge-formed metal plate 2, acting as the second waterproofing layer, prevents rainwater from seeping into the building even in extreme situations such as damage to the frameless photovoltaic glass 3. The fixing support 6, connecting groove 7, and fixing cap 8 together form an integrated connection assembly, enabling rapid assembly and connection between the frameless photovoltaic glass 3 and the self-locking edge-formed metal plate 2, eliminating the need for additional supports and component frames. The system as a whole adopts a prefabricated lightweight design, deeply integrating photovoltaic modules with the roof structure, simplifying on-site construction processes, improving construction efficiency, and simultaneously reducing the overall weight of the roof and the load-bearing pressure on the main roof structure.

[0054] In some embodiments, since the photovoltaic glass 1 used in this application is a frameless, bracketless photovoltaic glass, it is theoretically more prone to problems such as air leakage and water leakage. Therefore, to avoid the above problems, the photovoltaic glass uses a co-extrusion process to prepare the encapsulating film. The main substrate is a co-extruded polyolefin elastomer (POE). The core layer contains hydrolysis-resistant stabilizers, by weight percentage: Hydrolysis stabilizer: 0.6%–1.0%, preferably 0.8%. The hydrolysis stabilizer is selected from one or more of carbodiimides (such as monomeric or polymeric carbodiimides), isocyanates, oxazoline compounds, or epoxy compounds.

[0055] In this embodiment, a polymeric carbodiimide is preferred. This stabilizer can react with the terminal carboxyl groups, terminal amine groups, and terminal hydroxyl groups generated during polymer hydrolysis to produce stable and harmless products, effectively preventing further degradation and chain scission.

[0056] The core layer also contains hindered amine light stabilizers (HALS) at a weight percentage of 0.4% to 0.7%, preferably 0.5%.

[0057] Hindered amine light stabilizers are tetramethylpiperidine derivatives, which can be selected from low molecular weight HALS, such as Tinuvin 770 and Chimassorb 944, or high molecular weight / polymeric HALS, such as Tinuvin 622 and Chimassorb 2020.

[0058] Tinuvin 622 is preferred in this embodiment. HALS, when combined with benzotriazole UV absorbers, has a synergistic effect, which can significantly extend the lifespan of photovoltaic panels.

[0059] The core layer also contains a silane coupling agent, which is 0.2% to 0.4% by weight. In this embodiment, 0.3% is preferred, which is used to improve the adhesion strength between the adhesive film and the glass substrate.

[0060] The surface is modified by adding a low molecular weight fluorohydrophobic agent. The fluorohydrophobic agent is a short-chain (C6) environmentally friendly fluorocarbon surfactant that does not contain PFOA. SUNMORL® FN-Series or NMR-FL001 is preferred.

[0061] By precisely controlling the extrusion temperature, pressure, and injection speed, the aforementioned polymer materials with different functions (adhesion, hydrophobicity, hydrolysis resistance, and photoaging resistance) are co-extruded in the same mold to form a composite film. This film combines the high water-blocking properties of POE with the easy processing advantages of EVA, providing adhesion, protection, and insulation for double-glass photovoltaic modules.

[0062] Tests showed that, compared to traditional EVA films, the co-extruded POE modified encapsulating film of this embodiment has improved hydrolysis resistance by more than 40%, water resistance by more than 50%, and its resistance to potential-induced degradation (PID) is significantly better than that of traditional encapsulating films.

[0063] In some embodiments, for the four sides of the frameless photovoltaic glass, since there is no traditional frame and the glass edges are directly exposed, fluorine-modified butyl rubber sealing tape is used for sealing and reinforcement.

[0064] Specifically, 10%–15% polytetrafluoroethylene (PTFE) micropowder is added to the main butyl rubber for modification to improve the material's anti-aging and hydrophobic properties. A 1–2 μm nano-silica hydrophobic coating is then applied to the tape surface.

[0065] After preparation, the hydrophobic angle of the sealing tape is ≥110°, preferably ≥115°. This tape can not only improve the mechanical protection of the four sides of the photovoltaic glass and meet the impact resistance requirements during handling and installation, but also further block the path of water vapor penetration along the glass edge, forming a double sealing barrier with the modified POE film.

[0066] In some embodiments, moisture detection is performed during the production and finished product stages to ensure packaging effectiveness.

[0067] Specifically, a Karl Fischer moisture analyzer was used to measure the moisture content of POE granules and functional additives to ensure that the moisture content of the raw materials was below 0.05%.

[0068] During the film lamination process, a miniature capacitive or fiber optic humidity sensor is embedded to monitor the moisture content inside the adhesive layer in real time, and an automatic alarm is triggered when the moisture content exceeds the standard.

[0069] After the encapsulated photovoltaic glass module is evacuated, it is immersed in a dyeing liquid, and the presence of the colored liquid is observed to seep into the module; alternatively, positive pressure is applied to the entire system, and leaks are detected by pressure differential. This method provides a direct assessment of the encapsulation's sealing performance.

[0070] Only photovoltaic glass that passes the above tests can be installed in the roof system.

[0071] In one embodiment, such as Figure 1 As shown, a U-shaped enclosing sealing layer 5 is provided around the four edges of the frameless photovoltaic glass 3. The U-shaped enclosing sealing layer 5 is continuously arranged along the four edges of the frameless photovoltaic glass 3, and its cross-section is U-shaped, completely enclosing the edges of the glass.

[0072] The U-shaped sealing layer 5 is used to form a complete closed protection for the edge of the frameless photovoltaic glass 3. During the manufacturing process of the frameless photovoltaic glass 3, the U-shaped sealing layer 5 is attached to the edge of the glass by extrusion molding or prefabrication and is tightly bonded to the glass body.

[0073] The U-shaped enclosing sealing layer 5 wraps around the edge of the glass, which can absorb and buffer external impact forces, prevent damage such as chipping and cracking of the glass edge, and meet the strength requirements of the components for production, transportation and on-site construction.

[0074] The interface between the glass and the encapsulating film of the frameless photovoltaic glass 3 is a potential channel for moisture intrusion. The U-shaped enclosed sealing layer 5 forms a continuous physical barrier around the glass, blocking the path of moisture diffusion from the outside along the glass edge to the inside. Together with the internal POE encapsulating film, it forms a dual moisture protection system, thereby improving the long-term reliability of the module in humid environments.

[0075] In one embodiment, such as Figure 2As shown, the connecting groove 7 is an H-shaped connecting groove. The H-shaped connecting groove includes an upper groove 701 and a lower groove 702, which are respectively snapped into the upper and lower side edges of the frameless photovoltaic glass 3.

[0076] The upper mounting groove 701 is pre-bonded to the lower edge of a frameless photovoltaic glass 3 using sealant 9, and the lower mounting groove 702 is sealed to the upper edge of another adjacent frameless photovoltaic glass 3 using a waterproof strip 10. The connecting groove 7 is bonded to the glass during the factory pre-assembly stage to form an integrated module that is then transported to the site.

[0077] During on-site installation, the upper locking groove 701 is positioned along with the previous glass pane, while the lower locking groove 702 is pressed tightly against the upper edge of the next glass pane using a waterproof strip 10, achieving rapid connection and sealing between two adjacent frameless photovoltaic glass panes 3. This H-shaped connecting groove enables rapid assembly between glass panes. The upper locking groove 701 and lower locking groove 702 respectively hold the edges of the upper and lower glass panes, allowing the glass panes to overlap sequentially along the roof slope, eliminating the need for additional supports or pressure blocks and resulting in high assembly efficiency.

[0078] The hollow portion of the H-shaped connecting groove forms a sloping water guide channel, which orderly guides and drains any small amount of rainwater that may seep into the glass joint, preventing water accumulation. The upper groove 701 is pre-bonded to the glass with sealant 9 to form a strong initial seal; the lower groove 702 is elastically pressed to the glass by a waterproof strip 10, which can adapt to displacement caused by thermal expansion and contraction, and maintain a long-term sealing effect to prevent rainwater from seeping down from the joint.

[0079] In one embodiment, such as Figure 11 As shown, waterproof strips 10 are provided between the self-locking edge-formed metal plate 2 and the frameless photovoltaic glass 3, and between the fixed cover 8 and the frameless photovoltaic glass 3.

[0080] A waterproof strip 10 is laid between the upper surface of the self-locking profiled metal plate 2 and the lower surface of the frameless photovoltaic glass 3. The waterproof strip 10 is continuously arranged along the length of the frameless photovoltaic glass 3 and is located at the point where the glass edge contacts the metal plate. The waterproof strip 10 is made of high-quality rubber material, possessing elasticity and aging resistance.

[0081] The waterproof strip 10 is positioned between the rigid metal plate and the rigid glass. It can absorb the deformation and impact force of the roof caused by wind load, temperature change or equipment vibration, and prevent the glass from breaking or the metal plate from directly contacting the metal plate.

[0082] Waterproof strip 10 fills the gap between the metal plate and the glass, blocking the path of rainwater backflow or seepage from the edge of the glass and preventing moisture from entering the cavity between the upper surface of the metal plate and the glass.

[0083] The waterproof strip 10 separates the metal plate from the photovoltaic glass to prevent direct contact between the two and the generation of a conductive circuit or potential difference, while also preventing the surface of the metal plate from scratching the coating or film on the back of the glass.

[0084] After the roof metal panels are laid over a long distance, there may be slight height differences or unevenness. The waterproof strip 10, relying on its own compression elasticity, can adapt to the local undulations on the surface of the metal panel, so that the frameless photovoltaic glass 3 can be evenly supported, ensuring that the glass is evenly stressed and firmly attached.

[0085] A waterproof strip 10 is provided between the fixed cover 8 and the frameless photovoltaic glass 3, located on the inner side of the fixed cover 8 and the upper surface edge of the frameless photovoltaic glass 3. The fixed cover 8 is pressed onto the fixed support 6 and presses the glass edge tightly, with the waterproof strip 10 located on the contact surface between the cover and the glass.

[0086] The waterproof strip 10 provides elastic contact between the fixing cap 8 and the glass, so that the fixing cap 8 can fix the glass with appropriate pressure, ensuring that the clamping force is sufficient to prevent the glass from loosening, and avoiding the rigid cap from directly contacting the glass and causing indentation or cracking.

[0087] Waterproof strip 10 fills the gap between the fixing cap 8 and the upper surface of the glass to prevent rainwater from seeping into the connection node from the edge of the cap, thereby enhancing the waterproof sealing of the connection node.

[0088] The waterproof strip 10 can absorb the slight relative displacement caused by wind-induced vibration or temperature changes, reduce the abnormal noise caused by friction or collision between the fixed cover 8 and the glass, and at the same time avoid long-term vibration from causing wear on the glass edge.

[0089] Based on the above technical solutions, they together form an elastic sealing system between the frameless photovoltaic glass 3 and the metal support structure, providing buffer protection and sealing isolation from both below and above the glass, ensuring the long-term stable operation of the system.

[0090] In one embodiment, such as Figure 3 As shown, the self-locking profiled metal sheet 2 includes a sheet body 201. Self-locking protrusions 202 are spaced apart on the sheet body 201, and glass support protrusions 203 are provided between adjacent self-locking protrusions 202. Overlapping protrusions 204 are provided along the edges of the sheet body 201. The self-locking protrusions 202, glass support protrusions 203, and overlapping protrusions 204 are all continuous structures formed along the width direction of the self-locking profiled metal sheet 2.

[0091] The sheet body 201 is the base part of the self-locking profiled metal sheet 2, and is flat in shape. It is used to connect the various protruding structures and bear the distributed load. The self-locking protrusions 202 are arranged at intervals along the length of the sheet body 201, and each self-locking protrusion 202 is formed by rising upward from the sheet body 201.

[0092] The self-locking protrusion 202 is used to form a self-locking connection with the top of the fixing support 6, and at the same time provides a mounting base for the fixing cover 8. The distance between two adjacent self-locking protrusions 202 matches the width of the frameless photovoltaic glass 3.

[0093] The glass support protrusion 203 is positioned between two adjacent self-locking protrusions 202, rising upwards from the main body of the plate 201, with its height lower than that of the self-locking protrusions 202. The upper surface of the glass support protrusion 203 is flat, used to directly support the lower surface of the frameless photovoltaic glass 3. The glass support protrusion 203 is continuously arranged along the length of the metal plate, providing continuous linear or intermittent point support for the glass. The function of the glass support protrusion 203 is to maintain a certain gap between the frameless photovoltaic glass 3 and the main body of the plate 201, facilitating air circulation, while reducing the contact area between the glass and the metal plate, thus reducing friction and wear.

[0094] The overlapping protrusion 204 is set on the longitudinal edge of the main body of the sheet 201 for transverse overlapping connection between two adjacent self-locking profiled metal sheets 2. The cross-sectional shape of the overlapping protrusion 204 matches the mating structure of the edges of the adjacent metal sheets, and the rapid connection between the sheets is achieved by interlocking or pressing to form a continuous roof covering layer.

[0095] The aforementioned self-locking edge protrusion 202, glass support protrusion 203, and overlapping protrusion 204 are continuously processed on the metal sheet through a one-time roll forming process. The cross-sectional shape and relative position of each protrusion structure remain consistent throughout the entire length of the metal sheet. This structural design enables the self-locking edge profiled metal sheet 2 to provide a precise positioning and support reference surface for the frameless photovoltaic glass 3 while possessing load-bearing capacity, eliminating the need for additional pads or leveling components.

[0096] In one embodiment, such as Figure 3 and Figure 11As shown, the self-locking edge protrusion 202 includes a rectangular protrusion 2021, and an arc-shaped protrusion 2022 is provided at the top of the rectangular protrusion 2021. The rectangular protrusion 2021 extends vertically upward from the main body of the plate 201, forming a rectangular cavity with a certain height. The arc-shaped protrusion 2022 is located at the top of the rectangular protrusion 2021, and its cross-section is arc-shaped or semi-circular. The top of the arc-shaped protrusion 2022 tapers inward to form a slot structure. A fixing cap 8 is engaged at the top of the arc-shaped protrusion 2022. The lower end of the fixing cap 8 is provided with a claw that matches the arc-shaped protrusion 2022. The claw engages with the slots at the top of the arc-shaped protrusion 2022 from both sides, realizing the mechanical locking of the fixing cap 8 and the self-locking edge protrusion 202. The area formed by the fixing cap 8, the arc-shaped protrusion 2022, and the rectangular protrusion 2021 is used to fix the frameless photovoltaic glass 3. Specifically, the edge of the frameless photovoltaic glass 3 is clamped between the fixing cover 8 and the glass support protrusion 203. The fixing cover 8 applies a downward clamping force to firmly fix the edge of the glass.

[0097] The self-locking edge protrusion 202 is a hollow structure, meaning that the interior of the rectangular protrusion 2021 forms a cavity that runs through the length of the metal plate. The top of the fixing support 6 passes through this hollow structure and interlocks with the interior of the arc-shaped protrusion 2022. The top of the fixing support 6 is equipped with a locking head, which extends from below the rectangular protrusion 2021 into the hollow cavity and hooks upwards to engage with the inner wall of the arc-shaped protrusion 2022, thus locking the self-locking edge profiled metal plate 2 entirely onto the fixing support 6.

[0098] Understandably, the rectangular protrusion 2021 of the self-locking edge protrusion 202 provides sufficient vertical height, allowing the arc-shaped protrusion 2022 to be positioned higher, facilitating the installation and removal of the fixing cap 8. The arc-shaped surface of the arc-shaped protrusion 2022 helps guide rainwater to both sides, preventing rainwater accumulation at the connection joint. The snap-fit ​​connection between the fixing cap 8 and the arc-shaped protrusion 2022 allows for quick fixation without additional fasteners, resulting in high assembly efficiency. The hollow structure of the self-locking edge protrusion 202 reduces the weight of the metal plate while providing space for the top of the fixing support 6 to pass through and lock, achieving a concealed connection between the metal plate and the lower support structure. The connection joint is not exposed, improving the overall aesthetics and waterproof reliability of the roof.

[0099] In one embodiment, such as Figure 7 and Figure 8 As shown, the system also includes a ventilation and cooling device 11. The ventilation and cooling device 11 is installed between adjacent frameless photovoltaic glass 3 and connects the air layer between the frameless photovoltaic glass 3 and the self-locking edge-formed metal plate 2 with the outside atmosphere.

[0100] The ventilated cooling device 11 includes tempered glass 1101, with multiple vent caps 1102 formed along its length on the surface of the tempered glass 1101. The size and thickness of the tempered glass 1101 are basically the same as those of the frameless photovoltaic glass 3, allowing it to be smoothly embedded in the photovoltaic glass array. The vent caps 1102 are tubular or louvered openings penetrating the upper and lower surfaces of the tempered glass 1101, and the multiple vent caps 1102 are evenly arranged along the length of the tempered glass 1101. The upper opening of the vent cap 1102 communicates with the outside atmosphere, and the lower opening communicates with the air layer between the frameless photovoltaic glass 3 and the self-locking edge-formed metal plate 2.

[0101] The tempered glass 1101 is connected to the adjacent frameless photovoltaic glass 3 via a connecting groove 7. Specifically, the upper and lower edges of the tempered glass 1101 are connected to the frameless photovoltaic glass 3 on the upper and lower sides via H-shaped connecting grooves, respectively. The connection method is the same as that between ordinary photovoltaic glass, which allows the ventilation and cooling device 11 to be easily inserted into any predetermined position of the photovoltaic array as a standard unit module.

[0102] When the sun shines, the air layer between the frameless photovoltaic glass 3 and the self-locking edge-formed metal plate 2 is heated. As the internal air temperature rises, its density decreases, causing it to rise. The vent cap 1102 provides an outlet for this hot air. The hot air flows out naturally from the upper opening of the vent cap 1102, while cooler external air enters from other gaps or lower positions, forming a continuous natural convection circulation. This process effectively reduces the temperature of the back panel of the frameless photovoltaic glass 3, preventing the air layer between the glass and the metal plate from becoming too hot and affecting the power generation efficiency of the photovoltaic cells. Simultaneously, the structural design of the vent cap 1102 prevents external rainwater from flowing back into the air layer through the vent holes. Rain guards or curved air channels can be installed at the opening of the vent cap 1102 to ensure that rainwater does not flow into the upper surface of the metal roof panel even in heavy rain. For ultra-long pitched roofs, installing a ventilation and cooling device 11 at an appropriate position in the horizontal direction of the photovoltaic module array can break the airflow boundary layer, enhance the ventilation effect of the long pitch, effectively solve the problem of increased airflow resistance over long distances, and ensure smooth airflow under the entire roof.

[0103] In one embodiment, such as Figure 11 , Figure 13 and Figure 14 As shown, at least one layer of insulation board 12 is disposed below the self-locking profiled metal sheet 2. The insulation board 12 is connected to the support base 15 fixed to the roof purlin 1. The insulation board 12 is laid below the self-locking profiled metal sheet 2 and above the vapor barrier 13. As a special thermal insulation structural layer for the roof, the insulation board 12 can be made of materials such as rock wool board, polyurethane board or extruded polystyrene board, and its thickness is determined according to the climate conditions and building energy conservation requirements of the region.

[0104] The support base 15 is pre-fixed to the top surface of the roof purlin 1 by self-tapping screws or through bolts. The insulation board 12 is connected to the support base 15 by plugging, bonding or pressing, so that the insulation board 12 forms a continuous and stable insulation layer throughout the entire roof area.

[0105] A vapor barrier 13 is installed beneath the insulation board 12 and is fixed to the support base 15. The vapor barrier 13 is laid between the insulation board 12 and the roof purlins 1, and is typically made of waterproof and breathable membrane or polyethylene film. The vapor barrier 13 covers the entire roof surface, and its edges are sealed with sealing tape at the junction with the support base 15 to ensure the continuity of the vapor barrier.

[0106] The vapor barrier 13, positioned beneath the insulation layer, effectively prevents indoor humid vapors from penetrating upwards and intruding into the insulation layer, thus eliminating condensation inside the roof at its source. Without the vapor barrier 13, when warm, humid indoor air rises and encounters the cooler insulation board 12 or metal plate, the moisture condenses into liquid water, causing the insulation material to become damp and its thermal performance to deteriorate, resulting in insulation failure. The vapor barrier 13 prevents this problem. Simultaneously, the vapor barrier 13 reduces the erosion of steel structure panels by moisture, delaying steel corrosion and aging. The insulation board 12 and the lower vapor barrier 13 work synergistically to double-block indoor humid vapors from penetrating the insulation layer, maintaining the original thermal insulation performance of the insulation material, comprehensively improving the roof's thermal insulation effect, and extending the overall service life of the roof structure. In practical implementation, two or more layers of insulation board 12 can be installed as needed, with staggered joints between layers to eliminate cold bridging effects and further improve insulation performance.

[0107] In one embodiment, such as Figure 4 and Figure 5 As shown, the fixed support member 6 is a continuous component, cold-bent from a metal sheet, with an inverted Z-shaped or C-shaped cross-section. The bottom of the fixed support member 6 has a horizontal flange with pre-drilled mounting holes for inserting self-tapping screws 14 or through bolts. The top of the fixed support member 6 has a locking head for engaging with the self-locking edge structure of the self-locking profiled metal sheet 2. The fixed support member 6 is connected to the roof purlin 1 via a support base 15.

[0108] like Figure 6As shown, the support base 15 is an independent metal stamping part. Its bottom has a horizontal base plate that fits against the upper surface of the roof purlin 1. The base plate is bent upwards on both sides to form side plates, and the top of the side plates has a slot for engaging and fixing the support member 6. During installation, the support base 15 is fixed to the top surface of the roof purlin 1 using self-tapping screws or through bolts arranged evenly. The fixing support member 6 is continuously arranged along the longitudinal length of the roof, and its bottom is engaged and locked into the slot of the support base 15. The top of the fixing support member 6 passes through the hollow structure of the self-locking edge protrusion 202 of the self-locking edge profiled metal plate 2, forming a self-locking connection with the inner top wall of the self-locking edge protrusion 202. The fixing support member 6 and the support base 15 together provide reliable anchoring for the self-locking edge profiled metal plate 2 and the frameless photovoltaic glass 3, ensuring the overall coordination and load-bearing stability of the photovoltaic system and the roof structure.

[0109] On the other hand, the present invention also provides a construction method for a prefabricated frameless waterproof BIPV roofing system based on any of the above claims.

[0110] This construction method is carried out on the basis of the newly built factory building with the steel structure and roof purlins 1 already installed, and the construction sequence is from bottom to top. Specifically, it includes the following steps.

[0111] The first step is to install the support base 15 and the fixing support 6 on the roof purlin 1. For example... Figure 12 As shown, the support bases 15 are evenly arranged and fixed to the top surface of the roof purlins 1 using self-tapping screws 14 or through bolts. The spacing and arrangement of the support bases 15 are in accordance with the design requirements. After the support bases 15 are installed in place, they are straightened and corrected to ensure flatness, uniform stress, and stable connection. Then, the fixing support members 6 are continuously laid along the longitudinal length of the roof, and their bottoms are inserted into the slots of the support bases 15 and locked, providing a reliable load-bearing support system for the subsequent laying of the roof metal panels.

[0112] The second step is to install the vapor barrier 13. (For example...) Figure 13 As shown, a vapor barrier 13 is laid above the roof purlins 1 and below the insulation board 12. The vapor barrier 13 is made of waterproof and breathable membrane or polyethylene film, laid between the support bases 15 and fixed to the support bases 15. The vapor barrier 13 is used to prevent indoor humid hot water vapor from penetrating upwards and invading the insulation layer, eliminating condensation inside the roof from the source, avoiding the thermal performance degradation of the insulation material after it gets damp, and reducing the corrosion of the steel structure panels by water vapor.

[0113] The third step is to install insulation board 12. (Example) Figure 14As shown, an insulation board 12 is laid above the vapor barrier 13 and below the self-locking profiled metal sheet 2. The insulation board 12 is made of rock wool, polyurethane, or extruded polystyrene, and its thickness is determined according to building energy conservation requirements. The insulation board 12 is connected to the support base 15 fixed on the roof purlin 1, and can be fixed by plugging or pressing. The insulation board 12 is used to block the exchange of heat between indoors and outdoors, reduce the conduction of hot and cold air, and avoid the formation of cold bridges on the roof. The insulation board 12 works in conjunction with the lower vapor barrier 13 to doubly block indoor moisture from entering the insulation layer, maintaining the stable thermal insulation performance of the insulation material.

[0114] Step four: Install the entire length of the fixing support 6 (if the fixing support 6 has already been installed in step one, this step is for inspection or supplementation). For example... Figure 15 As shown, the continuous fixed support member 6 is laid out along the longitudinal direction of the roof. Its top is used to fasten with the self-locking edge structure of the self-locking edge profiled metal plate 2, and at the same time provides edge support points for the frameless photovoltaic glass 3.

[0115] Step 5: Install the self-locking edge-formed metal sheet 2. (For example...) Figure 16 As shown, the self-locking edge profiled metal sheet 2 is laid on top of the insulation board 12. The self-locking edge profiled metal sheet 2 is made using a high-strength corrugated molding process, and its edges form a self-locking edge structure. The self-locking edge protrusion 202 of the self-locking edge profiled metal sheet 2 is aligned with the top lock head of the fixing support 6, and fixed by a self-locking connection, so that the hollow structure of the self-locking edge protrusion 202 wraps around the top of the fixing support 6 and locks it tight. Adjacent self-locking edge profiled metal sheets 2 can be quickly overlapped through the self-locking edge structure of the sheet edges to form an integral roof. This metal sheet, as the second waterproof layer, is customized according to the external dimensions of the frameless photovoltaic glass 3, providing a flat installation reference surface.

[0116] Step 6: Pre-assemble the frameless photovoltaic glass 3 and the connecting groove 7. In the factory, an automatic glue applicator is used to apply sealant 9 to the lower edge of the frameless photovoltaic glass 3. Then, the upper groove 701 of the connecting groove 7 is bonded to the glass edge to form an integrated component. The sealant 9 applied by the automatic glue applicator has a thickness of 1.5 ± 0.2 mm, and the hardness of the sealant after curing is not less than 80 Shore A. The connecting groove 7 is an H-type connecting groove, including an upper groove 701 and a lower groove 702. The upper groove 701 is pre-bonded to the glass edge with sealant 9, and a waterproof strip 10 is pre-installed in the lower groove 702.

[0117] Step 7: Lay out frameless photovoltaic glass on site. (Example: ...) Figure 17As shown, the pre-assembled integrated modules are transported to the site and laid sequentially on top of the self-locking edge-formed metal sheet 2 along the roof slope from the eaves to the ridge. The lower locking groove 702 of the upper glass panel is pressed tightly against the upper edge of the lower glass panel using a waterproof strip 10, so that adjacent integrated modules are connected to each other through H-shaped connecting grooves. For ultra-long pitched roofs, a ventilation and cooling device 11 is installed at a predetermined position in the lateral direction of the photovoltaic module array. The tempered glass 1101 of the ventilation and cooling device 11 is connected to the adjacent frameless photovoltaic glass 3 through a connecting groove 7, and the vent cap 1102 of the ventilation and cooling device 11 connects the air layer between the glass and the metal sheet to the outside atmosphere.

[0118] Step 8: Install and secure the pressure cap. (e.g., ...) Figure 18 As shown, the fixing cap 8 is pressed onto the fixing support 6. The lower claw of the fixing cap 8 engages with the arc-shaped protrusion 2022 on the top of the self-locking edge protrusion 202, while the fixing cap 8 presses the edge of the frameless photovoltaic glass 3 tightly. A waterproof strip 10 is provided between the fixing cap 8 and the upper surface of the glass. The fixing cap 8 is anchored at intervals using self-tapping screws 14. After pressing, the installation of the entire BIPV roofing system is completed.

[0119] This method combines factory pre-assembly with rapid on-site assembly, reducing on-site construction procedures, ensuring the sealing quality of connection nodes, and achieving prefabricated lightweight construction.

[0120] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A prefabricated, frameless, waterproof BIPV roofing system, comprising roof purlins, characterized in that, Also includes: Self-locking edge profiled metal sheet, the self-locking edge profiled metal sheet is fixed above the roof purlin; The frameless photovoltaic glass is laid directly on top of the profiled metal sheet. The photovoltaic cells are encapsulated using co-extruded POE modified encapsulating film. Fluorine-modified butyl rubber sealing tape is set around the edges of the frameless photovoltaic glass. The frameless photovoltaic glass constitutes the first waterproof layer and power generation layer of the roof, and the profiled metal sheet constitutes the second waterproof layer and structural support layer of the roof. A fixed support member, the bottom of which is fixed to the roof purlin, and the top of which is connected to the profiled metal sheet and supports the edge of the frameless photovoltaic glass; The connecting groove is an integral structure and is set at the joint of two adjacent frameless photovoltaic glass pieces to connect and seal the joint along the roof slope. The fixing cap is pressed onto the fixing support and the edge of the frameless photovoltaic glass is pressed and fixed.

2. The roofing system according to claim 1, characterized in that, The co-extruded POE modified encapsulating film has a main substrate made of co-extruded polyolefin elastomer (POE), a core layer with 0.6%-1.0% hydrolysis stabilizer, 0.4%-0.7% hindered amine light stabilizer, and 0.2%-0.4% silane coupling agent, and a surface layer modified with low molecular weight fluorine hydrophobic agent.

3. The roofing system according to claim 2, characterized in that, The hydrolysis-resistant stabilizer is selected from one or more of carbodiimides, isocyanates, oxazoline compounds, or epoxy compounds; the hindered amine light stabilizer is a tetramethylpiperidine derivative.

4. The roofing system according to claim 1, characterized in that, The fluorine-modified butyl rubber sealing tape has 10%-15% polytetrafluoroethylene micro powder added to the main butyl rubber for modification, and the tape surface is coated with a 1-2μm nano-silica hydrophobic coating with a surface hydrophobic angle ≥110°.

5. The roofing system according to claim 1, characterized in that, The frameless photovoltaic glass has a U-shaped sealing layer around its four edges.

6. The roofing system according to claim 1, characterized in that, The connecting groove is an H-shaped connecting groove, including an upper groove and a lower groove, which are respectively snapped and connected to the upper and lower side edges of the frameless photovoltaic glass; The upper groove is pre-bonded to the edge of the photovoltaic glass using sealant, and the lower groove is sealed to the edge of the other photovoltaic glass using a waterproof strip.

7. The roofing system according to claim 1, characterized in that, Waterproof strips are provided between the self-locking edge-formed metal plate and the frameless photovoltaic glass, as well as between the fixed cover and the frameless photovoltaic glass.

8. The roofing system according to claim 1, characterized in that, The self-locking edge-formed metal sheet includes a sheet body; The main body of the plate is provided with self-locking edge protrusions at intervals, and glass support protrusions are provided between adjacent self-locking edge protrusions. The edge of the main body of the plate is provided with overlapping protrusions. The self-locking edge protrusion, the glass support protrusion, and the overlapping protrusion are all continuous structures formed along the width direction of the self-locking edge profiled metal sheet.

9. The roofing system according to claim 1, characterized in that, The self-locking edge protrusion includes a rectangular protrusion, and an arc-shaped protrusion is provided on the top of the rectangular protrusion. The top of the arc-shaped protrusion is engaged with the fixing cover. The area enclosed by the fixing cover, the arc-shaped protrusion, and the rectangular protrusion is used to fix the frameless photovoltaic glass. The self-locking edge protrusion has a hollow structure, and the top of the fixing support passes through the hollow structure and interlocks with the interior of the arc-shaped protrusion.

10. The roofing system according to claim 1, characterized in that, It also includes a ventilation and cooling device, which is installed between adjacent frameless photovoltaic glass and connects the air layer between the frameless photovoltaic glass and the profiled metal plate with the outside atmosphere; The breathable cooling device includes tempered glass, and multiple vent caps are formed on the surface of the tempered glass along its length. The tempered glass is connected to the adjacent frameless photovoltaic glass via the connecting groove.

11. The roofing system according to claim 1, characterized in that, At least one layer of insulation board is provided below the self-locking edge-formed metal sheet, and the insulation board is connected to the support base fixed on the roof purlin; A vapor barrier layer is provided below the insulation board, and the vapor barrier layer is fixed to the support base.

12. A construction method for a prefabricated, frameless, waterproof BIPV roofing system according to any one of claims 1-11, characterized in that, Includes the following steps: Install fixed support bases and fixed support components on the roof purlins; A vapor barrier and insulation board are laid sequentially above the roof purlins; Install the profiled metal sheet and connect the profiled metal sheet to the fixed support member; The edges of the frameless photovoltaic glass are coated with sealant and pre-installed with metal clips to form an integrated module. The pre-assembled integrated components are transported to the site and laid on top of the profiled metal sheet along the roof slope, so that adjacent components are connected to each other through the H-shaped connecting groove. Install the fixing cap to press and fix the edge of the frameless photovoltaic glass onto the fixing support.

13. The construction method of the prefabricated frameless waterproof BIPV roofing system according to claim 12, characterized in that, The thickness of the sealant layer applied by the automatic glue applicator is 1.5±0.2mm, and the hardness of the sealant after curing is ≥80 Shore A.

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