Photovoltaic aluminum profile and method for manufacturing the same

Abstract

The application discloses a kind of photovoltaic aluminum profile and preparation method thereof, it is related to aluminum alloy profile and photovoltaic module installation material technical field, the aluminum alloy profile matrix includes the following components by mass percentage: silicon 0.55-0.85%, magnesium 0.45-0.75%, manganese 0.05-0.20%, iron 0.08-0.25%, titanium 0.01-0.05%, chromium 0.02-0.10%, copper≤0.08%, zinc≤0.10%, the balance is aluminum and unavoidable impurities;The weather-proof protective layer includes micro-etching activation layer, anodic oxide film layer, sealing layer and silane modified stain-resistant layer in order from the side close to matrix to outer surface;By controlling Si, Mg, Mn, Cr, Ti and other element content, and limiting Cu and Zn content, photovoltaic aluminum profile is obtained higher aging strengthening effect at the same time, reduce the corrosion sensitivity under outdoor humid and salt fog environment.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy profiles and photovoltaic module installation materials, specifically to a photovoltaic aluminum profile and its preparation method. Background Technology

[0002] Photovoltaic aluminum profiles are widely used in photovoltaic module frames, clamps, rails, brackets, and roofing installation systems. Because photovoltaic modules are exposed to the outdoor environment for extended periods, photovoltaic aluminum profiles must withstand wind loads, snow loads, temperature and humidity cycles, ultraviolet radiation, salt spray corrosion, rainwater erosion, and acid and alkaline deposits. Therefore, photovoltaic aluminum profiles not only need high tensile strength, yield strength, and dimensional stability, but also good surface corrosion resistance, stain resistance, and drainage capacity.

[0003] Existing photovoltaic aluminum profiles typically use ordinary 6063 series or similar aluminum alloy extruded profiles, which are then anodized or sprayed. While this type of profile can meet general usage requirements, the following problems still exist in actual outdoor applications: First, the Mg and Si ratios of some aluminum alloy profiles are not properly controlled, resulting in insufficient precipitation of aging-strengthening phases. This leads to insufficient profile strength or large strength fluctuations, especially under thin-walled and lightweight design conditions, which can easily cause local deformation or instability of the mounting groove under stress. Second, conventional photovoltaic frame profiles focus more on support and installation functions, while insufficiently considering the problems of water accumulation, condensation, and rainwater retention at the module edges. When there is local water accumulation in the support area of ​​the profile, moisture and dust easily accumulate at the module edges, which may accelerate the aging of the encapsulating adhesive edges, corrosion of the profile surface, and contamination deposition over a long period of time.

[0004] Therefore, it is necessary to provide a new photovoltaic aluminum profile and its preparation method. Through the coordinated design of aluminum alloy composition control, cross-sectional structure optimization and multi-level weather-resistant protective layer, the profile can further improve its corrosion resistance, stain resistance, weather resistance and drainage performance while meeting the requirements of lightweight and installation strength. Summary of the Invention

[0005] The purpose of this invention is to address the problems of insufficient strength and stability, poor drainage of water accumulation at the edges, insufficient bonding and corrosion resistance of the anodic oxide film, and easy surface contamination in existing photovoltaic aluminum profiles, and to provide a photovoltaic aluminum profile and its preparation method.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a photovoltaic aluminum profile, comprising an aluminum alloy profile substrate and a weather-resistant protective layer formed on the surface of the aluminum alloy profile substrate.

[0007] The aluminum alloy profile matrix comprises the following components by mass percentage: Si 0.55-0.85%, magnesium 0.45-0.75%, manganese 0.05-0.20%, iron 0.08-0.25%, titanium 0.01-0.05%, chromium 0.02-0.10%, copper ≤0.08%, zinc ≤0.10%, with the balance being aluminum and unavoidable impurities.

[0008] By controlling the Si and Mg content, a strengthening phase dominated by Mg2Si can be formed in the profile during artificial aging, thereby improving the tensile strength and yield strength of the profile; by controlling the Mn, Cr and Ti content, the grain structure and extrusion forming stability can be improved; by limiting the Cu and Zn content, the electrochemical corrosion sensitivity of the profile in humid and salt spray environments can be reduced.

[0009] Furthermore, the mass ratio of magnesium to silicon in the aluminum alloy profile matrix is ​​0.75-1.10, and the excess silicon content in the Si used to form the Mg2Si strengthening phase is 0.05-0.20%. This ratio can balance extrusion formability, aging strengthening effect, and corrosion resistance, avoiding insufficient strengthening due to too low Mg content, and also avoiding increased susceptibility to grain boundary corrosion due to too high Mg or free Si content.

[0010] The aluminum alloy profile substrate includes a component support section, a vertical support section, and a mounting connection section. The component support section is provided with a support step for supporting the edge of the photovoltaic module. The vertical support section has a closed reinforcing cavity inside. The mounting connection section has a bolt mounting groove extending along the length of the profile. The closed reinforcing cavity improves the bending and torsional stiffness of the profile cross-section, and the bolt mounting groove facilitates the connection between the photovoltaic module and the support system.

[0011] Furthermore, at least one reinforcing rib is provided within the enclosed reinforcing cavity. The reinforcing rib connects the opposing inner walls of the vertical support portion. The thickness of the reinforcing rib is 1.0-2.5 mm, and the thickness of the outer wall of the vertical support portion is 1.3-3.0 mm. By providing reinforcing ribs, the local load-bearing capacity of the profile can be improved without significantly increasing the amount of aluminum used.

[0012] Furthermore, the component support portion has a sealing strip positioning groove on one side near the edge of the photovoltaic module. The groove has an opening width of 2.0-5.0 mm and a depth of 1.5-4.0 mm. The sealing strip positioning groove is used to install sealing strips or buffer strips, which can improve the positioning stability and sealing reliability of the component edge.

[0013] Furthermore, the component support is also provided with a drainage channel, which extends along the length of the profile, and the bottom surface of the drainage channel is inclined outward at 1-5° relative to the support step, for guiding accumulated water to the outside of the profile and draining it. This inclined drainage structure can reduce the probability of long-term water accumulation at the edge of the component and reduce the retention of dust, salt and pollutants on the surface of the profile.

[0014] The weather-resistant protective layer consists of, from the side closest to the aluminum alloy profile substrate to the outer surface, a micro-etching activation layer formed by alkaline or acid etching processes, an anodic oxide film layer, a sealing layer, and a silane-modified stain-resistant layer.

[0015] The micro-etching activation layer is formed by alkaline or acid etching, and its surface has a fine uneven structure, which is beneficial to improving the uniformity of subsequent anodic oxide film formation and the stability of interfacial bonding. The anodic oxide film is used to improve the corrosion resistance and surface hardness of the profile. The sealing layer is used to seal the pores of the anodic oxide film and reduce the penetration of corrosive media. The silane-modified stain-resistant layer is used to further improve the hydrophobicity, stain resistance, ease of cleaning, and durability stability after artificial weathering of the profile surface.

[0016] Furthermore, the thickness of the anodic oxide film is 8-18 μm. If the thickness of the anodic oxide film is less than 8 μm, the corrosion resistance is insufficient; if the thickness exceeds 18 μm, the processing energy consumption increases, and the internal stress of the film increases, which is not conducive to cost control and long-term stability.

[0017] Furthermore, the sealing layer is one of a hot water sealing layer, a nickel salt sealing layer, or a nickel-free composite sealing layer. Preferably, considering the environmental protection requirements in photovoltaic applications, the sealing layer can be a nickel-free composite sealing layer.

[0018] Furthermore, the silane-modified antifouling layer is formed from one or more of fluorinated silanes, aminosilanes, or epoxysilanes, with a thickness of 0.2-2.0 μm. The silane-modified antifouling layer can bond with the surface of the sealed oxide film through silicon-oxygen bonds or condensation networks, thereby improving the surface's antifouling, waterproofing, anti-fouling adhesion ability, and performance retention rate after aging.

[0019] This invention also provides a method for preparing photovoltaic aluminum profiles, comprising the following steps: S1. The aluminum alloy profile matrix is ​​batched, smelted, and refined according to the component ratio to obtain an aluminum alloy melt; S2. After degassing, slag removal and filtration, the aluminum alloy melt is cast into aluminum alloy round casting rods at 680-730℃. S3. The aluminum alloy round casting rod is homogenized at 540-570℃ for 4-10 hours, and then cooled to room temperature; S4. Heat the homogenized aluminum alloy round casting rod to 470-520℃ and extrude it through an extrusion die into a profile blank with a component support part, a vertical support part, an installation connection part and a closed reinforcing cavity. S5. The profile blank is subjected to online air cooling or water mist cooling, and then stretched, straightened and cut to length to obtain a straightened profile. S6. The straightened profile is subjected to artificial aging treatment to obtain a reinforced profile; S7. The reinforced profile is first degreased, alkali-etched and acid-washed to form a micro-etched activation layer; then it is anodized to form an anodized film layer; then it is sealed to form a sealing layer; finally it is impregnated with silane modification solution and cured at 80-120℃ to form a silane-modified stain-resistant layer, thus obtaining the photovoltaic aluminum profile.

[0020] Furthermore, in step S1, the melting temperature is 720-760℃, the refining is carried out by argon or nitrogen rotary blowing refining, and the refining time is 10-25min; the filtration is carried out by ceramic filter plate filtration, and the filter plate pore size is 30-50ppi.

[0021] Further, in step S4, the extrusion cylinder temperature is 430-470℃, the extrusion die temperature is 450-500℃, the extrusion speed is 6-18m / min, the extrusion ratio is 25-60, and the extrusion outlet temperature is controlled at 500-540℃.

[0022] Further, in step S6, the artificial aging treatment is to keep the material at 170-190℃ for 3-8 hours; after the artificial aging treatment, the tensile strength of the reinforced profile is not less than 240MPa, the yield strength is not less than 200MPa, and the elongation after fracture is not less than 8%.

[0023] Further, in step S7, anodizing is carried out using sulfuric acid electrolyte with a concentration of 150-200 g / L, an oxidation temperature of 18-24℃, a current density of 1.0-1.8 A / dm², and an oxidation time of 20-45 min; after sealing, the profile is immersed in a silane modification treatment solution with a mass concentration of 0.5-3.0% for 1-5 min, and cured at 80-120℃ for 10-30 min.

[0024] Compared with the prior art, the present invention provides a photovoltaic aluminum profile and its preparation method, which has the following beneficial effects: by controlling the content of elements such as Si, Mg, Mn, Cr, and Ti, and limiting the content of Cu and Zn, the photovoltaic aluminum profile can achieve a high aging strengthening effect while reducing the corrosion sensitivity in outdoor humid and salt spray environments.

[0025] This invention improves the profile cross-sectional stiffness and installation load-bearing capacity through the coordinated structural design of the component support, vertical support, installation connection, closed reinforcement cavity and reinforcing rib, which is conducive to meeting the requirements of lightweight and high strength of photovoltaic module frame and bracket system.

[0026] The present invention provides a drainage channel with the bottom surface inclined outward in the component support part, which can guide water accumulated at the edge of the component to the outside of the profile and discharge it, reducing the risk of water retention and pollution deposition.

[0027] This invention improves the interfacial bonding stability, sealing integrity, salt spray resistance, dirt resistance, and performance retention rate after artificial climate aging of the anodic oxide film through a multi-level weather-resistant protection structure consisting of a micro-etching activation layer, an anodic oxide film layer, a sealing layer, and a silane-modified anti-fouling layer. Attached Figure Description

[0028] Figure 1 This is a SEM image of the cross-section of the weather-resistant protective layer of the photovoltaic aluminum profile in Embodiment 4 of the present invention; Figure 2 This is a SEM image of the micro-etched activation layer on the surface of the photovoltaic aluminum profile in Embodiment 4 of the present invention; Figure 3 This is a SEM image of the anodic oxide film layer on the photovoltaic aluminum profile of Embodiment 4 of the present invention; Figure 4 This is an EDS surface distribution diagram of Si, O, and F elements on the surface of the photovoltaic aluminum profile in Embodiment 4 of the present invention. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Please see Figures 1-4 This invention provides a technical solution for photovoltaic aluminum profiles and their preparation method: In the following examples, all aluminum alloy components are expressed as mass percentages; unless otherwise specified, all percentages are mass percentages.

[0031] The aluminum ingots, magnesium ingots, aluminum-silicon master alloys, aluminum-manganese master alloys, aluminum-titanium-boron master alloys, and aluminum-chromium master alloys used in the examples and comparative examples were all industrial-grade raw materials. Anodizing was performed using a sulfuric acid system, and sealing was achieved using one of the following: hot water sealing, nickel salt sealing, or nickel-free composite sealing. The silane modification treatment solution was an aqueous alcohol system containing fluorinated silanes, aminosilanes, or epoxysilanes.

[0032] Example 1 A photovoltaic aluminum profile, wherein the aluminum alloy profile matrix comprises, by weight percentage: 0.55% silicon, 0.45% magnesium, 0.05% manganese, 0.08% iron, 0.01% titanium, 0.02% chromium, 0.03% copper, 0.04% zinc, with the balance being aluminum and unavoidable impurities.

[0033] The aluminum alloy profile substrate includes a component support, a vertical support, and an installation connection. The vertical support has a closed reinforcing cavity inside, with a reinforcing rib inside the cavity. The reinforcing rib has a thickness of 1.0 mm, and the outer wall thickness of the vertical support is 1.3 mm. The component support has a rubber strip limiting groove with a groove opening width of 2.0 mm and a groove depth of 1.5 mm. The component support also has a drainage guide groove, with the bottom surface of the drainage guide groove inclined outwards at 1° relative to the support step.

[0034] The preparation method is as follows: S1. According to the above alloy composition, melt at 720°C and refine with argon rotary blowing for 10 minutes to obtain aluminum alloy melt. S2. After degassing and removing slag from the aluminum alloy melt, it is filtered through a 30ppi ceramic filter plate and cast into an aluminum alloy round casting rod at 680℃. S3. Homogenize the aluminum alloy round casting rod at 540℃ for 4 hours, and then cool it to room temperature. S4. The homogenized aluminum alloy round casting rod is heated to 470℃, the extrusion cylinder temperature is 430℃, the extrusion die temperature is 450℃, the extrusion speed is 6m / min, the extrusion ratio is 25, and the extrusion outlet temperature is 500℃ to obtain the profile billet. S5. The profile blank is subjected to online air cooling, stretching and straightening and cut to length to obtain straightened profiles; S6. The straightened profile is artificially aged at 170℃ for 3 hours to obtain the reinforced profile. S7. The reinforced profile is first degreased, alkali-etched, and acid-washed to form a micro-etched activation layer; then, it is anodized using sulfuric acid electrolyte with a concentration of 150 g / L, an oxidation temperature of 18℃, a current density of 1.0 A / dm², and an oxidation time of 20 min to form an anodized film layer with a thickness of about 8 μm; subsequently, hot water sealing treatment is performed to form a sealing layer; finally, the profile is immersed in an aminosilane modification treatment solution with a mass concentration of 0.5% for 1 min and cured at 80℃ for 10 min to form a silane-modified anti-fouling layer with a thickness of about 0.2 μm, thus obtaining a photovoltaic aluminum profile.

[0035] Example 2 A photovoltaic aluminum profile, wherein the aluminum alloy profile matrix comprises, by weight percentage: 0.85% silicon, 0.75% magnesium, 0.20% manganese, 0.25% iron, 0.05% titanium, 0.10% chromium, 0.08% copper, 0.10% zinc, with the balance being aluminum and unavoidable impurities.

[0036] Two reinforcing ribs are installed inside the enclosed reinforced cavity, with a thickness of 2.5mm. The outer wall thickness of the vertical support is 3.0mm. The groove width of the rubber strip limiting groove is 5.0mm and the groove depth is 4.0mm. The bottom surface of the drainage guide groove is inclined outward at 5° relative to the supporting step.

[0037] In the preparation method, the melting temperature is 760℃, and the nitrogen rotary spray refining is carried out for 25 min; the pore size of the ceramic filter plate is 50 ppi; the casting temperature is 730℃; the homogenization treatment temperature is 570℃ and the holding time is 10 h; the casting rod heating temperature is 520℃, the extrusion cylinder temperature is 470℃, the extrusion die temperature is 500℃, the extrusion speed is 18 m / min, the extrusion ratio is 60, the extrusion outlet temperature is 540℃; and the artificial aging treatment temperature is 190℃ and the holding time is 8 h.

[0038] During anodizing, the sulfuric acid electrolyte concentration was 200 g / L, the oxidation temperature was 24°C, the current density was 1.8 A / dm², and the oxidation time was 45 min, forming an anodized film layer with a thickness of approximately 17.8 μm. Nickel-free composite sealing was used for pore sealing. The silane modification treatment solution was a 3.0% (w / w) fluorinated silane solution, which was impregnated for 5 min and cured at 120°C for 30 min, forming a silane-modified anti-fouling layer with a thickness of approximately 2.0 μm. The remaining steps were the same as in Example 1.

[0039] Example 3 A photovoltaic aluminum profile, wherein the aluminum alloy profile matrix comprises, by weight percentage: 0.70% silicon, 0.58% magnesium, 0.12% manganese, 0.16% iron, 0.03% titanium, 0.06% chromium, 0.05% copper, 0.06% zinc, with the balance being aluminum and unavoidable impurities.

[0040] A reinforcing rib with a thickness of 1.8 mm is installed inside the enclosed reinforcing cavity, and the outer wall thickness of the vertical support is 2.2 mm. The groove width of the rubber strip limiting groove is 3.5 mm and the groove depth is 2.8 mm; the bottom surface of the drainage guide groove is inclined outward at 3° relative to the supporting step.

[0041] In the preparation method, the melting temperature is 740℃, and the argon rotary blowing refining is carried out for 18 min; the pore size of the ceramic filter plate is 40 ppi; the casting temperature is 705℃; the homogenization treatment temperature is 555℃ and the holding time is 7 h; the casting rod heating temperature is 495℃, the extrusion cylinder temperature is 450℃, the extrusion die temperature is 475℃, the extrusion speed is 12 m / min, the extrusion ratio is 42, the extrusion outlet temperature is 520℃; and the artificial aging treatment temperature is 180℃ and the holding time is 5.5 h.

[0042] During anodizing, the sulfuric acid electrolyte concentration was 175 g / L, the oxidation temperature was 21°C, the current density was 1.4 A / dm², and the oxidation time was 32 min, forming an anodized film layer with a thickness of approximately 13 μm. Nickel-free composite sealing was used for pore sealing. The silane modification treatment solution was a 1.5% (w / w) composite solution of fluorinated silane and aminosilane, which was impregnated for 3 min and cured at 100°C for 20 min, forming a silane-modified anti-fouling layer with a thickness of approximately 1.0 μm. The remaining steps were the same as in Example 1.

[0043] Example 4 A photovoltaic aluminum profile, wherein the aluminum alloy profile matrix comprises, by weight percentage: 0.68% silicon, 0.60% magnesium, 0.15% manganese, 0.14% iron, 0.035% titanium, 0.08% chromium, 0.04% copper, 0.05% zinc, with the balance being aluminum and unavoidable impurities.

[0044] Two reinforcing ribs with a thickness of 1.8 mm are installed inside the enclosed reinforced cavity, and the outer wall thickness of the vertical support is 2.4 mm. The bottom surface of the drainage guide channel is inclined outward at 3° relative to the supporting step.

[0045] The thickness of the anodic oxide film was controlled to be 15 μm; nickel-free composite sealing was used for pore sealing; the silane modification treatment solution was a composite treatment solution of fluorinated silane, amino silane, and epoxy silane with a mass concentration of 2.0%, wherein the mass ratio of fluorinated silane, amino silane, and epoxy silane was 3:1:1. The immersion treatment was carried out for 4 min, and then cured at 110°C for 25 min to form a silane-modified stain-resistant layer. The remaining preparation steps were the same as in Example 3.

[0046] Example 5 A photovoltaic aluminum profile, wherein the aluminum alloy profile matrix comprises, by weight percentage: 0.62% silicon, 0.52% magnesium, 0.10% manganese, 0.10% iron, 0.02% titanium, 0.04% chromium, 0.02% copper, 0.03% zinc, with the balance being aluminum and unavoidable impurities.

[0047] A reinforcing rib with a thickness of 1.5 mm is installed inside the enclosed reinforcing cavity, and the outer wall thickness of the vertical support is 2.0 mm. The bottom surface of the drainage guide channel is inclined outward at 2° relative to the supporting step.

[0048] Water mist cooling was used during the preparation process; the artificial aging treatment temperature was 175℃, and the holding time was 6h; the thickness of the anodic oxide film was controlled at 12μm; hot water sealing was used for pore sealing; the silane modification treatment solution was a 1.2% (w / w) epoxy silane treatment solution, which was impregnated for 2.5min and cured at 95℃ for 18min. The remaining steps were the same as in Example 3.

[0049] Example 6 A photovoltaic aluminum profile, wherein the aluminum alloy profile matrix comprises, by weight percentage: 0.76% silicon, 0.66% magnesium, 0.16% manganese, 0.18% iron, 0.04% titanium, 0.07% chromium, 0.05% copper, 0.05% zinc, with the balance being aluminum and unavoidable impurities.

[0050] Two reinforcing ribs, each 2.0 mm thick, are installed inside the enclosed reinforced cavity. The outer wall thickness of the vertical support is 2.5 mm. The bottom surface of the drainage guide channel is inclined outward at 4° relative to the supporting step.

[0051] During the preparation process, the homogenization treatment temperature was 560℃, and the holding time was 8 hours; the artificial aging treatment temperature was 185℃, and the holding time was 5 hours; the thickness of the anodic oxide film was controlled to be 16 μm; nickel-free composite sealing was used; the silane modification treatment solution was a 2.5% (w / w) composite treatment solution of fluorinated silane and epoxy silane, which was impregnated for 4 minutes and cured at 115℃ for 25 minutes. The remaining steps were the same as in Example 3.

[0052] Comparative Example 1 differs only in that: no silane modification treatment is performed after sealing, and no silane-modified anti-fouling layer is formed. All other alloy compositions, profile structures, anodized film thickness, and sealing processes are the same as in Example 3.

[0053] Comparative Example 2 differs only in that: no alkaline or acid etching is performed during the surface pretreatment to form a micro-etching activation layer; instead, conventional degreasing and cleaning are performed before direct anodizing. All other conditions are the same as in Example 3.

[0054] Comparative Example 3 differs only in that the anodizing time is shortened, resulting in an anodized film thickness of approximately 6 μm, which is lower than the 8 μm lower limit specified in this invention. All other conditions are the same as in Example 3.

[0055] Comparative Example 4 differs only in that the magnesium content in the aluminum alloy profile matrix is ​​adjusted to 0.35%, and the silicon content is maintained at 0.70%, so that the mass ratio of Mg to Si is lower than the preferred range of this invention. The remaining alloying elements, structure, and surface treatment process are the same as in Example 3.

[0056] Comparative Example 5 differs only in that the bottom surface of the drainage channel does not slope outwards; its bottom surface is essentially parallel to the supporting step, with an inclination angle of 0°. The remaining structural dimensions, alloy composition, and surface treatment process are the same as in Example 3.

[0057] Comparative Example 6 differs only in that: the vertical support section does not have a closed reinforcing cavity, but instead uses an open cavity structure, and it does not have reinforcing ribs connecting to the opposite inner walls. The remaining alloy composition and surface treatment process are the same as in Example 3.

[0058] The performance testing method is as follows: 1. Mechanical property testing: Prepare aluminum alloy profile tensile specimens and conduct tensile tests according to the method specified in GB / T 16865-2023.

[0059] 2. General performance evaluation of profiles: The quality of profiles is evaluated in accordance with the technical requirements for general industrial aluminum and aluminum alloy extruded profiles in GB / T 6892-2023.

[0060] 3. Evaluation of anodic oxide film thickness and appearance: Evaluation shall be conducted in accordance with GB / T 5237.2-2017 and GB / T 8013.1-2018.

[0061] 4. Salt spray corrosion resistance test: Neutral salt spray test shall be conducted in accordance with GB / T 10125-2021 for 720h, 1000h, 1200h or 1500h, and the corrosion of the sample surface shall be observed.

[0062] 5. Coating adhesion test: Conduct a cross-cut test according to GB / T 9286-2021 and record the adhesion level.

[0063] 6. Surface hardness test: Pencil hardness test shall be conducted in accordance with GB / T 6739-2022.

[0064] 7. Stain resistance test: Stain resistance was evaluated in accordance with GB / T 9780-2013, and the stain removal rate was recorded.

[0065] 8. Artificial Climate Aging Test: The filtered xenon arc radiation artificial climate aging test was conducted according to GB / T 1865-2009, with an aging time of 1000 hours. After aging, the sample surface was observed for obvious powdering, cracking, loss of gloss, or peeling. The contamination removal rate was tested again, and the contamination removal rate retention rate after aging was calculated. The contamination removal rate retention rate after aging was calculated using the following formula: The retention rate of contaminant removal rate after aging = contaminant removal rate after aging ÷ contaminant removal rate before aging × 100%.

[0066] 9. Drainage Performance Test: Place a 300mm long profile sample horizontally, keeping the supporting step in its actual installation position. Add 10mL of deionized water to the inside of the component's supporting part, let it stand for 90 seconds, and then weigh the amount of water remaining in the drainage channel. This test is used to evaluate the drainage effect of the drainage channel.

[0067] 10. Section stiffness test: A 600mm long profile sample is simply supported at both ends, a 500N load is applied at the mid-span, and the maximum deflection at the mid-span is measured after holding for 60s. This is used to evaluate the influence of the closed reinforcing cavity and stiffeners on the section stiffness.

[0068] The test results are shown in the table below. Table 1

[0069] The test results above show that: The tensile strength of Examples 1-6 is not less than 240 MPa, the yield strength is not less than 200 MPa, and the elongation after fracture is not less than 8%, indicating that the aluminum alloy composition ratio and artificial aging system of the present invention can meet the strength requirements of photovoltaic aluminum profiles.

[0070] Compared with Example 3, Comparative Example 4 only changed the Mg content, so that the ratio of Mg to Si deviated from the preferred range of the present invention. Its tensile strength decreased to 224 MPa and its yield strength decreased to 181 MPa, indicating that reasonable control of the ratio of Mg to Si has a significant effect on the aging strengthening effect of the profile.

[0071] Compared with Example 3, Comparative Example 1 omitted the silane-modified antifouling layer, and its contamination removal rate decreased from 94.4% to 74.8%. After 1000 hours of xenon lamp aging, the contamination removal rate retention rate decreased from 90.6% to 58.7%, and the appearance rating after salt spray also decreased. This indicates that the silane-modified antifouling layer can not only improve the initial antifouling performance, but also improve the antifouling retention ability and weathering stability after artificial climate aging.

[0072] Compared with Example 3, Comparative Example 2 omitted only the micro-etching activation layer, and its cross-cut adhesion decreased from level 0 to level 2. After the salt spray test, local gloss loss and corrosion spots appeared on the film. After 1000 hours of xenon lamp aging, the pollution removal rate retention rate decreased to 72.1%. This indicates that the micro-etching activation layer formed by alkaline or acid etching is beneficial to improving the bonding stability between the anodic oxide film and the aluminum alloy substrate, and has a promoting effect on the long-term stability of the subsequent weather-resistant protective layer.

[0073] Compared with Example 3, Comparative Example 3 only reduced the thickness of the anodic oxide film to 6.1 μm, and obvious corrosion points appeared after 480 h of salt spray, indicating that controlling the thickness of the anodic oxide film within the range of 8-18 μm can effectively ensure corrosion resistance.

[0074] Compared with Example 3, Comparative Example 5 only set the bottom of the drainage channel to 0°. The residual water volume in 90s increased from 0.41 mL to 5.86 mL. Slight watermark corrosion appeared near the drainage channel after the salt spray test. This shows that tilting the bottom of the drainage channel outward by 1-5° can effectively promote the drainage of accumulated water and reduce the risk of local corrosion caused by the retention of water and pollutants.

[0075] Compared with Example 3, Comparative Example 6 only removed the closed reinforcing cavity and the stiffener structure. The profile deflection under 500N load increased from 1.05mm to 3.24mm, indicating that the closed reinforcing cavity and the stiffener can significantly improve the profile cross-sectional stiffness.

[0076] In this invention, excess silicon content refers to the percentage of silicon by mass remaining after deducting the silicon content required to form Mg2Si with Mg according to the stoichiometric relationship of Mg2Si.

[0077] Figure 1 In this study, the aluminum profile sample prepared in Example 4 was cut along its cross-section, embedded in cold-mounted resin, and sequentially water-polished with 240#, 600#, 1000#, and 2000# sandpaper. It was then polished to a mirror finish with 1.0 μm diamond, ultrasonically cleaned, and dried. Finally, it underwent surface sputtering (5 kV, 60 s) to enhance conductivity. From the outer surface to the inner side, the sealed and silane-modified dense surface layer, the anodic oxide film, and the aluminum alloy substrate are visible. The fine undulating interface near the aluminum alloy substrate corresponds to the micro-etched activation layer. The arrow on the left indicates the approximate measurement location of the film thickness, and the scale bar in the lower right corner is 5 μm.

[0078] Figure 2 In Example 4, a sample (approximately 10 mm × 10 mm) was cut from the surface of an aluminum profile before anodizing (after degreasing, alkaline etching, and pickling). After rinsing with deionized water, ultrasonically cleaning with anhydrous ethanol (3 min), and drying with cold air, a metal layer of approximately 10 nm was sputtered in an ion sputtering apparatus (30 s) to improve conductivity. The testing conditions were: accelerating voltage 5.0 kV; working distance 8.0 mm; signal type secondary electron (SE); vacuum degree ≤ 1 × 10⁻⁶. - ³ Pa; magnification 10000×; the micro-etched pits in the figure are shallow pit structures formed after alkaline etching / acid washing; the micro-protrusions are the localized substrate undulations; the continuously distributed micro-grooves constitute the micro-etched activation layer, which is beneficial to the uniform film formation of the subsequent anodic oxide film.

[0079] Figure 3 In Example 4, a sample (approximately 10 mm × 10 mm) was cut from the surface of an aluminum profile after anodizing (film thickness approximately 15 μm, before sealing). After rinsing with deionized water, the sample was ultrasonically cleaned in anhydrous ethanol for 3 min and then dried with cold air. An approximately 10 nm gold layer was sputtered onto the surface using an ion sputtering apparatus (30 s) to improve surface conductivity. The testing conditions were: accelerating voltage 5.0 kV; working distance 8.0 mm; signal type secondary electron (SE); vacuum degree ≤ 1 × 10⁻⁶. - ³ Pa; magnification 50000×; the nano-sized pores in the figure are the openings formed during the anodizing process; the pore wall structure is the alumina skeleton between adjacent pores; the surface of the anodized film is continuous, uniformly porous, and no obvious ablation or cracking defects are observed.

[0080] Figure 4 In this study, samples were taken from the exposed surface of the photovoltaic aluminum profile after anodizing, nickel-free composite sealing, and silane modification treatment as described in Example 4. The sample size was approximately 10 mm × 10 mm. Before testing, the samples were lightly cleaned with deionized water and anhydrous ethanol, and then dried with cold air. To avoid interference from the metal spraying layer on EDS elemental analysis, the samples were not metal-sprayed. Testing was conducted in low vacuum mode or under appropriately reduced beam current conditions. The testing conditions were: accelerating voltage 15 kV; working distance 9.5 mm; signal type EDSX X-ray signal; vacuum degree ≤ 1 × 10⁻⁶. - ³ Pa; Scan area 150μm×150μm; Pixels 256×256; Acquisition time 120s; The image shows the surface distribution of Si, O, and F elements from left to right. Higher brightness / color indicates higher signal intensity (relatively higher content) of the element. Scale bar 10μm.

[0081] In summary, this invention, through the synergistic combination of aluminum alloy composition control, drainage-type cross-sectional structure design, and multi-level weather-resistant protective layer preparation process, enables the resulting photovoltaic aluminum profile to possess high mechanical strength, good drainage capacity, excellent salt spray resistance, surface stain resistance, and stain resistance retention after artificial climate aging. This meets the long-term reliability requirements of photovoltaic module frames, rails, brackets, and related outdoor installation systems.

Claims

1. A photovoltaic aluminum profile, characterized in that, Includes an aluminum alloy profile substrate and a weather-resistant protective layer formed on the surface of the aluminum alloy profile substrate; The aluminum alloy profile matrix comprises the following components by weight percentage: silicon 0.55-0.85%, magnesium 0.45-0.75%, manganese 0.05-0.20%, iron 0.08-0.25%, titanium 0.01-0.05%, chromium 0.02-0.10%, copper ≤0.08%, zinc ≤0.10%, with the balance being aluminum and unavoidable impurities; The aluminum alloy profile substrate includes a component support part, a vertical support part, and an installation connection part. The component support part is provided with a support step for supporting the edge of the photovoltaic module. The vertical support part is provided with a closed reinforcement cavity. The installation connection part is provided with a bolt mounting groove extending along the length of the profile. The weather-resistant protective layer consists of, from the side closest to the aluminum alloy profile substrate to the outer surface, a micro-etching activation layer formed by alkaline or acid etching processes, an anodic oxide film layer, a sealing layer, and a silane-modified stain-resistant layer.

2. The photovoltaic aluminum profile according to claim 1, characterized in that, The mass ratio of magnesium to silicon in the aluminum alloy profile matrix is ​​0.75-1.

10.

3. The photovoltaic aluminum profile according to claim 1, characterized in that, The enclosed reinforcing cavity is provided with at least one reinforcing rib, which is connected between the opposite inner walls of the vertical support part, and the thickness of the reinforcing rib is 1.0-2.5mm, while the thickness of the outer wall of the vertical support part is 1.3-3.0mm.

4. A photovoltaic aluminum profile according to claim 1, characterized in that, The component support part is provided with a rubber strip limiting groove on one side near the edge of the photovoltaic module. The groove opening width is 2.0-5.0mm and the groove depth is 1.5-4.0mm. The component support part is also provided with a drainage guide groove, which extends along the length of the profile and the bottom surface of the drainage guide groove is inclined outward at 1-5° relative to the support step, so as to guide the accumulated water to the outside of the profile and drain it.

5. A photovoltaic aluminum profile according to claim 1, characterized in that, The thickness of the anodic oxide film layer is 8-18 μm, and the sealing layer is one of hot water sealing layer, nickel salt sealing layer or nickel-free composite sealing layer; the silane modified antifouling layer is formed by one or more of fluorinated silane, amino silane or epoxy silane, with a thickness of 0.2-2.0 μm, and the pollution removal rate is not less than 85% after 1000h xenon lamp aging.

6. A method for preparing a photovoltaic aluminum profile as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. The aluminum alloy profile matrix is ​​batched, smelted, and refined according to the component ratio of claim 1 to obtain an aluminum alloy melt; S2. After degassing, slag removal and filtration, the aluminum alloy melt is cast into aluminum alloy round casting rods at 680-730℃. S3. The aluminum alloy round casting rod is homogenized at 540-570℃ for 4-10 hours, and then cooled to room temperature; S4. Heat the homogenized aluminum alloy round casting rod to 470-520℃ and extrude it through an extrusion die into a profile blank with a component support part, a vertical support part, an installation connection part and a closed reinforcing cavity. S5. The profile blank is subjected to online air cooling or water mist cooling, and then stretched, straightened and cut to length to obtain a straightened profile. S6. The straightened profile is subjected to artificial aging treatment to obtain a reinforced profile; S7. The reinforced profile is first degreased, alkali-etched and acid-washed to form a micro-etched activation layer; then it is anodized to form an anodized film layer; then it is sealed to form a sealing layer; finally it is impregnated with silane modification solution and cured at 80-120℃ to form a silane-modified stain-resistant layer, thus obtaining the photovoltaic aluminum profile.

7. The method for preparing a photovoltaic aluminum profile according to claim 6, characterized in that, In step S1, the melting temperature is 720-760℃, the refining is carried out by argon or nitrogen rotary blowing, and the refining time is 10-25 minutes; the filtration is carried out by ceramic filter plate with a pore size of 30-50 ppi.

8. The method for preparing a photovoltaic aluminum profile according to claim 6, characterized in that, In step S4, the extrusion cylinder temperature is 430-470℃, the extrusion die temperature is 450-500℃, the extrusion speed is 6-18m / min, the extrusion ratio is 25-60, and the extrusion outlet temperature is controlled at 500-540℃.

9. The method for preparing a photovoltaic aluminum profile according to claim 6, characterized in that, In step S6, the artificial aging treatment involves holding the material at 170-190℃ for 3-8 hours. After the artificial aging treatment, the tensile strength of the reinforced profile is not less than 240MPa, the yield strength is not less than 200MPa, and the elongation after fracture is not less than 8%.

10. A method for preparing a photovoltaic aluminum profile according to claim 6, characterized in that, In step S7, anodizing is performed using sulfuric acid electrolyte with a concentration of 150-200 g / L, an oxidation temperature of 18-24℃, a current density of 1.0-1.8 A / dm², and an oxidation time of 20-45 min. After sealing, the profile is immersed in a silane modification treatment solution with a mass concentration of 0.5-3.0% for 1-5 min and cured at 80-120℃ for 10-30 min.

Images