A corrosion and cracking resistant photovoltaic cable and a method of making the same

Abstract

This invention discloses a corrosion-resistant and crack-resistant photovoltaic cable and its preparation method, relating to the field of photovoltaic cable technology. It addresses the technical problems of existing photovoltaic cables, such as the lack of effective chemical barrier protection at the conductor interface, easy cracking of the insulation layer under high temperature and thermal stress, and the lack of an anti-corrosion coating on the outer surface of the sheath leading to aging, cracking, and water ingress in chemically corrosive environments like acid, alkali, and salt spray. The photovoltaic cable includes a conductor, an insulation layer, and a sheath. The conductor is an ultra-flexible copper conductor, with a nano-inorganic anti-cracking layer on its outer surface, comprising aluminum silicate, alumina, silicon dioxide, and zinc oxide. The insulation layer is a low-smoke, halogen-free, radiation-crosslinked polyolefin insulation layer, composited with an anti-cracking composition containing polyetheretherketone, polyethersulfone, nano-silica, and nano-alumina. Ventilation grooves are provided on the outer surface of the insulation layer. The sheath is a vinyl chloride-ethylene copolymer sheath, coated with a reflective aluminum powder layer on its outer surface. An internal support frame made of glass fiber is provided within the sheath, filled with polyurethane buffer blocks. An anti-corrosion layer comprising polyamide, polyester, nano-alumina, and nano-silica is also provided on the outer surface of the sheath. Through the above-mentioned multi-level synergistic structure, it can effectively block the penetration of corrosive media, inhibit the cracking of the insulation layer, and reduce the photoaging rate of the sheath, making it suitable for photovoltaic power generation systems in harsh environments such as high altitude and plateau.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cable technology, specifically to a corrosion-resistant and crack-resistant photovoltaic cable and its preparation method. Background Technology

[0002] Photovoltaic cables are used outdoors for extended periods, requiring them to withstand the corrosive effects of multiple environmental factors, including ultraviolet radiation, temperature fluctuations, and acid / alkali / salt spray. A Chinese patent, CN117612781A, discloses a weather-resistant photovoltaic cable and its manufacturing method. This design includes a transmission component, a protection component, and an outer protective component. The protection component contains an insulation layer and a crack-resistant layer, while the outer protective component contains a radiation-resistant layer and an anti-corrosion layer. However, the material selection and structural design of the crack-resistant and anti-corrosion layers in this design still suffer from insufficient conductor interface protection and limited sheath corrosion resistance under chemically corrosive environments. A Chinese patent, CN207993560U, discloses a crack-resistant photovoltaic power generation cable. This design improves crack resistance by wrapping an ultra-thin glass fiber crack-resistant layer around the conductor and creating ventilation grooves on the outer surface of the insulation layer. However, the glass fiber wrapping layer in this scheme has limited chemical barrier capability against the conductor interface, and the outer surface of the sheath lacks an effective anti-corrosion coating. In high-temperature or chemically corrosive environments, the sheath still suffers from aging, cracking, and water ingress, affecting the service life and reliability of the cable. Summary of the Invention

[0003] The purpose of this invention is to provide a corrosion-resistant and crack-resistant photovoltaic cable and its preparation method, so as to solve the technical problems existing in the prior art, such as the lack of effective chemical barrier protection at the conductor interface of photovoltaic cables, the easy cracking of the insulation layer under high temperature and thermal stress, and the lack of anti-corrosion coating on the outer surface of the sheath, which leads to aging, cracking and water ingress of the sheath in chemical corrosion environments such as acid, alkali and salt spray.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A corrosion-resistant and crack-resistant photovoltaic cable includes a conductor, an insulation layer, and a sheath. The conductor is an ultra-flexible copper conductor, and the outer surface of the conductor is provided with a nano-inorganic crack-resistant layer. The nano-inorganic crack-resistant layer comprises aluminum silicate, aluminum oxide, silicon oxide, and zinc oxide. Aluminum silicate, aluminum oxide, silicon oxide, and zinc oxide are all inorganic nanomaterials with high hardness, chemical inertness, and thermal stability. They are directly coated on the outer surface of the conductor in the form of a nano-thin layer, which can block the erosion of the conductor interface by external mechanical stress and chemical media, and effectively improve the crack resistance and corrosion resistance of the conductor interface. The insulating layer is a low-smoke, halogen-free, radiation-crosslinked polyolefin insulating layer. The insulating layer contains an anti-cracking composition comprising polyetheretherketone (PEEK), polyethersulfone (PES), nano-silica, and nano-alumina. PEEK and PES are both high-heat-resistant, high-modulus engineering polymers, which, in synergistic filling with nano-silica and nano-alumina, enhance the toughness of the insulating layer and inhibit crack propagation. The outer surface of the insulating layer is provided with ventilation grooves. These grooves promote heat exchange between the inside and outside of the insulating layer, effectively reducing the temperature difference and thermal stress concentration, further improving the crack resistance of the insulating layer. The sheath is a vinyl chloride-ethylene copolymer sheath, which combines good corrosion resistance and flexibility. The outer surface of the sheath is coated with a reflective aluminum powder layer. The reflective aluminum powder reduces ultraviolet absorption through physical reflection, thereby reducing the photoaging rate of the sheath material. The sheath has a support frame made of glass fiber inside, which is filled with polyurethane buffer blocks. The glass fiber support frame provides rigid support, and the polyurethane buffer blocks absorb impact energy, working together to prevent the cable from bending or structural damage during use. The outer surface of the sheath is also provided with an anti-corrosion layer, which includes polyamide, polyester, nano-alumina, and nano-silica. Polyamide and polyester are composite to form a film, and nano-alumina and nano-silica fill to improve the coating density and block the penetration of corrosive media such as acids, alkalis, and salt sprays.

[0006] Furthermore, in the nano-inorganic anti-cracking layer, the content of aluminum silicate is 70-80 parts by weight, the content of aluminum oxide is 10-15 parts by weight, the content of silicon oxide is 5-10 parts by weight, and the content of zinc oxide is 2-5 parts by weight. The components within the above content range work together to form a uniform and dense nano-inorganic barrier layer on the surface of the conductor, taking into account both the mechanical strength and chemical stability of the coating.

[0007] Preferably, in the anti-cracking composition, the content of polyetheretherketone is 60-70 parts by weight, the content of polyethersulfone is 20-30 parts by weight, the content of nano-silica is 5-10 parts by weight, and the content of nano-alumina is 2-5 parts by weight; the ratio of polyetheretherketone to polyethersulfone is optimized so that the insulating layer can obtain a high heat distortion temperature and crack resistance while maintaining good processability.

[0008] Specifically, the ventilation slot has a width of 0.5-1.0 mm, a depth of 0.3-0.5 mm, and a spacing of 1.0-1.5 mm between adjacent ventilation slots; the ventilation slots with the above-mentioned dimensional parameters can achieve effective heat dissipation and ventilation while ensuring the integrity of the insulation layer structure.

[0009] In some embodiments, the number of ventilation slots is eight, and they are arranged uniformly and symmetrically along the outer surface of the insulation layer; the uniform and symmetrical distribution of the eight ventilation slots can achieve a better level of heat dissipation uniformity and thermal stress distribution in all directions of the insulation layer.

[0010] As a preferred embodiment, the thickness of the reflective aluminum powder layer is 0.1-0.2 mm; a reflective aluminum powder layer within this thickness range can form a continuous reflective film on the outer surface of the sheath, which has high reflectivity for ultraviolet rays, while not affecting the flexibility of the sheath.

[0011] Preferably, in the anti-corrosion layer, the content of polyamide is 40-50 parts by weight, the content of polyester is 30-40 parts by weight, the content of nano-alumina is 10-15 parts by weight, and the content of nano-silica is 5-10 parts by weight; under this ratio, the film density and chemical resistance of the anti-corrosion layer are both at a better level, and it can effectively block corrosive media such as salt spray, acid and alkali.

[0012] Furthermore, the support frame is a tubular structure; the tubular fiberglass support frame has a high moment of inertia, which can provide excellent bending stiffness while maintaining low density, effectively supporting the internal structure of the cable.

[0013] This invention also provides a method for preparing a corrosion-resistant and crack-resistant photovoltaic cable, comprising the following steps: coating the outer surface of an ultra-flexible copper conductor with a nano-inorganic crack-resistant layer, wherein the nano-inorganic crack-resistant layer comprises aluminum silicate, alumina, silicon dioxide, and zinc oxide, to obtain a conductor with a surface coated with the nano-inorganic crack-resistant layer; uniformly mixing a low-smoke halogen-free irradiated cross-linked polyolefin insulating material with an crack-resistant composition through a blending process, wherein the crack-resistant composition comprises polyetheretherketone, polyethersulfone, nano-silica, and nano-alumina, to prepare an insulating layer, and opening ventilation holes on the outer surface of the insulating layer. The process involves: mixing vinyl chloride-ethylene copolymer with reflective aluminum powder, preparing a sheath through extrusion, and coating the outer surface of the sheath with a reflective aluminum powder layer; uniformly mixing polyamide, polyester, nano-alumina, and nano-silica, and coating the outer surface of the sheath with a coating process to prepare an anti-corrosion layer; fabricating a tubular support frame from glass fiber, filling the inside of the tubular support frame with polyurethane buffer blocks, and placing the support frame inside the sheath; assembling the conductor obtained above sequentially with the insulation layer and the sheath, and combining the anti-corrosion layer and the support frame to obtain an anti-corrosion and crack-resistant photovoltaic cable.

[0014] Furthermore, the blending process is carried out at a temperature of 150-160℃ and a mixing time of 15-20 minutes. This temperature and time range can ensure that the low-smoke halogen-free irradiated cross-linked polyolefin insulation material and the crack-resistant composition are fully and uniformly mixed, while avoiding degradation of high-performance polymers such as polyether ether ketone due to excessively high temperatures.

[0015] Preferably, the extrusion process uses a twin-screw extruder with an extrusion temperature of 180-190℃; the strong shear mixing effect of the twin-screw extruder is beneficial to the uniform dispersion of reflective aluminum powder in the vinyl chloride-ethylene copolymer matrix, and the extrusion temperature range is adapted to the processing window of the vinyl chloride-ethylene copolymer.

[0016] Specifically, the coating process adopts a spraying method with a coating temperature of 20-25℃. Under normal temperature spraying conditions, the polyamide / polyester system has suitable fluidity, which is conducive to forming a uniform and dense anti-corrosion coating on the outer surface of the sheath.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention provides a nano-inorganic anti-cracking layer composed of aluminum silicate, aluminum oxide, silicon oxide and zinc oxide on the outer surface of the conductor. The above-mentioned inorganic nano-components have high chemical inertness and high hardness, and can form a dense inorganic barrier layer at the conductor interface, effectively blocking the corrosion of the conductor by external mechanical stress and chemical media such as acid, alkali and salt spray. This solves the problem of limited chemical barrier ability of glass fiber wrapping layer at the conductor interface in the prior art, and significantly improves the crack resistance and corrosion resistance of the conductor interface.

[0019] 2. This invention incorporates an anti-cracking composition composed of polyetheretherketone, polyethersulfone, nano-silica, and nano-alumina into the insulation layer, and sets ventilation grooves with a width of 0.5-1.0 mm, a depth of 0.3-0.5 mm, and a spacing of 1.0-1.5 mm on the outer surface of the insulation layer. The two work synergistically: the former enhances the toughness of the insulation layer and inhibits crack propagation by filling it with a high heat-resistant polymer matrix and nanoparticles, while the latter reduces thermal stress concentration by promoting internal and external heat exchange. Thus, the invention jointly inhibits the cracking of the insulation layer at both the material body and structural levels, solving the problem of easy cracking of the insulation layer under high temperature or thermal stress environment in the prior art.

[0020] 3. The present invention provides an anti-corrosion layer composed of polyamide, polyester, nano-alumina and nano-silica on the outer surface of the sheath. The polyamide / polyester composite film system has good chemical resistance, and the filling of nano-alumina and nano-silica further improves the coating density, which can effectively block corrosive media such as acid, alkali and salt spray from penetrating into the sheath. This solves the problem of the lack of an effective anti-corrosion coating on the outer surface of the sheath in the prior art, and significantly improves the corrosion resistance and service life of the cable in chemical erosion environment.

[0021] 4. The reflective aluminum powder coating on the outer surface of the sheath of this invention reduces ultraviolet absorption through physical reflection, thereby reducing the photoaging rate of the sheath material; the glass fiber support frame set inside the sheath provides rigid support, and the polyurethane buffer block absorbs impact energy. The two work together to prevent the cable from bending deformation or structural damage caused by external forces during use, further improving the overall weather resistance and structural reliability of the cable in harsh environments such as high altitude and plateau. Attached Figure Description

[0022] Figure 1 A schematic diagram of the overall cross-sectional structure of a corrosion-resistant and crack-resistant photovoltaic cable;

[0023] Figure 2 for Figure 1 A partial structural diagram showing the arrangement of ventilation slots on the outer surface of the middle insulation layer;

[0024] Figure 3 for Figure 1 A schematic diagram showing the relationship between the internal support frame and the polyurethane buffer block of the middle sheath;

[0025] Legend: 10, conductor; 20, nano-inorganic anti-cracking layer; 30, insulation layer; 40, sheath; 50, anti-corrosion layer; 31, ventilation slot; 40, sheath; 41, reflective aluminum powder layer; 42, support frame; 43, buffer block. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the embodiments. Unless otherwise specified, all raw materials used in the following embodiments are commercially available products. Aluminum silicate, alumina, silicon dioxide, zinc oxide, nano-silica, nano-alumina, polyetheretherketone, polyethersulfone, polyamide, polyester, etc., were all purchased from Sinopharm Chemical Reagent Co., Ltd., and were of industrial grade or analytical grade.

[0027] Test methods

[0028] The coating thickness was measured using a coating thickness gauge (model: DeFelsko PosiTector 6000). The dimensions of the ventilation slots were measured using precision vernier calipers.

[0029] The corrosion resistance test of the cable was conducted in accordance with the neutral salt spray test method of GB / T 2423.17. The temperature of the salt spray test chamber was 35℃ and the salt water concentration was 5% (mass fraction) NaCl solution.

[0030] The crack resistance test was conducted according to GB / T 2951.11 bending test method after thermal aging. The aging temperature was 135℃, the aging time was 168h, and the diameter of the bending mandrel was twice the outer diameter of the cable.

[0031] Mechanical performance testing was conducted according to GB / T 2951.11, with a tensile rate of 250 mm / min and a test temperature of 23 ± 2℃. Low-temperature bending testing was conducted according to GB / T 2951.14. The cable sample was placed in an environment of -40℃ for 4 hours, and then bent according to the specified core diameter. The surface of the sheath was observed for any cracks.

[0032] Weather resistance testing was conducted according to the xenon arc lamp aging test method in GB / T 16422.2, with an irradiance of 0.55 W / m² (340 nm), a black panel temperature of 65±3℃, and a relative humidity of 65±5%. Each 120-minute cycle included 18 minutes of spraying. The tensile strength and elongation at break retention were tested after 500 hours and 1000 hours of aging, respectively, and the surface chalking grade of the sheath was evaluated according to GB / T 1766.

[0033] Electrical performance tests shall be conducted according to GB / T 3048.4, measuring the DC resistance of the conductor (20℃), and according to GB / T 3048.5, measuring the insulation resistance. Withstand voltage tests shall be conducted according to GB / T 3048.8, applying an AC voltage of 3.5kV and holding for 5 minutes, observing for any breakdown.

[0034] Example 1

[0035] This embodiment prepares a corrosion-resistant and crack-resistant photovoltaic cable with a conductor (10) diameter of 1.0 mm. The specific preparation steps are as follows.

[0036] Step 1: Preparation of conductor. Take an ultra-flexible copper conductor with a diameter of 1.0 mm, mix the nano-inorganic anti-cracking layer (20) composed of 75 parts by weight of aluminum silicate, 12 parts by weight of aluminum oxide, 8 parts by weight of silicon oxide and 3 parts by weight of zinc oxide evenly, and coat it evenly on the outer surface of the ultra-flexible copper conductor by dip coating process, dry and cure to obtain a conductor (10) with a surface coated with nano-inorganic anti-cracking layer (20).

[0037] Step 2: Preparation of the insulation layer. 50 parts by weight of low-smoke halogen-free irradiated crosslinked polyolefin insulation material and 5 parts by weight of the anti-cracking composition were added to a mixer. The low-smoke halogen-free irradiated crosslinked polyolefin insulation material consisted of 40 parts by weight of linear low-density polyethylene, 12 parts by weight of nonylphenol dichloride copolymer, 3 parts by weight of organo-modified montmorillonite, 1 part by weight of zinc borate, and 1.5 parts by weight of 2,2'-methylenebis(4-tert-octyl-6-benzotriazolephenol). The anti-cracking composition consisted of polyetheretherketone, polyethersulfone, nano-silica, and nano-alumina. The mixture was stirred and kneaded at 150°C for 15 minutes. After uniform mixing, it was extruded and molded. Eight ventilation slots (31) were evenly opened along the circumferential direction on the outer surface of the insulation layer (30). The ventilation slots (31) were 0.5 mm wide and 0.3 mm deep, with a spacing of 1.0 mm between adjacent ventilation slots (31), thus obtaining the insulation layer (30).

[0038] Step 3: Preparation of the sheath. 60 parts by weight of vinyl chloride-ethylene copolymer material and 0.3 parts by weight of reflective aluminum powder are mixed evenly. The vinyl chloride-ethylene copolymer material is composed of 30 parts by weight of ethylene-octene copolymer, 20 parts by weight of ethylene vinyl acetate resin, 3 parts by weight of triallyl isocyanate, 1 part by weight of triphenyltriazine, 2 parts by weight of sodium dehydroacetate, and 1 part by weight of potassium sorbate. The sheath (40) is prepared by extrusion using a twin-screw extruder at an extrusion temperature of 180°C. Reflective aluminum powder is then uniformly sprayed onto the outer surface of the sheath (40) to form a reflective aluminum powder layer (41) with a thickness of 0.1 mm.

[0039] Step 4: Preparation of the anti-corrosion layer. Mix 45 parts by weight of polyamide, 35 parts by weight of polyester, 12 parts by weight of nano alumina and 8 parts by weight of nano silica evenly, and apply the mixture evenly to the outer surface of the sheath (40) at a temperature of 20°C using a spraying process to prepare the anti-corrosion layer (50).

[0040] Step 5: Prepare the support frame. Weave the glass fiber fabric into a rectangular tubular support frame (42), and fill the support frame (42) with a polyurethane buffer block (43), which is composed of 40 parts by weight of polyethersulfone, 30 parts by weight of polyethylene glycol, 20 parts by weight of polylactic acid and 10 parts by weight of nano silica. Place the support frame (42) inside the sheath (40).

[0041] The conductor (10) obtained in step one is assembled sequentially with the insulation layer (30) obtained in step two and the sheath (40) obtained in step three, and combined with the anti-corrosion layer (50) obtained in step four and the support frame (42) obtained in step five to obtain the anti-corrosion and crack-resistant photovoltaic cable of Example 1.

[0042] Example 2

[0043] This embodiment prepares a corrosion-resistant and crack-resistant photovoltaic cable with a conductor (10) diameter of 1.2 mm. The specific preparation steps are as follows.

[0044] Step 1: Preparation of conductor. Take an ultra-flexible copper conductor with a diameter of 1.2 mm, mix the nano-inorganic anti-cracking layer (20) composed of 78 parts by weight of aluminum silicate, 13 parts by weight of aluminum oxide, 7 parts by weight of silicon oxide and 3 parts by weight of zinc oxide evenly, and coat it evenly on the outer surface of the ultra-flexible copper conductor by dip coating process, dry and cure to obtain a conductor (10) with a surface coated with nano-inorganic anti-cracking layer (20).

[0045] Step 2: Preparation of the insulation layer. 55 parts by weight of low-smoke halogen-free irradiated crosslinked polyolefin insulation material and 7 parts by weight of the anti-cracking composition were added to a mixer. The low-smoke halogen-free irradiated crosslinked polyolefin insulation material consisted of 42 parts by weight of linear low-density polyethylene, 14 parts by weight of nonylphenol dichloride copolymer, 3.5 parts by weight of organo-modified montmorillonite, 1.5 parts by weight of zinc borate, and 2 parts by weight of 2,2'-methylenebis(4-tert-octyl-6-benzotriazolephenol). The anti-cracking composition consisted of polyetheretherketone, polyethersulfone, nano-silica, and nano-alumina. The mixture was stirred and mixed at 160°C for 20 minutes. After uniform mixing, it was extruded and molded. Eight ventilation slots (31) were evenly opened along the circumferential direction on the outer surface of the insulation layer (30). The ventilation slots (31) were 1.0 mm wide and 0.5 mm deep, with a spacing of 1.5 mm between adjacent ventilation slots (31), thus obtaining the insulation layer (30).

[0046] Step 3: Preparation of the sheath. 65 parts by weight of vinyl chloride-ethylene copolymer material and 0.4 parts by weight of reflective aluminum powder are mixed evenly. The vinyl chloride-ethylene copolymer material is composed of 32 parts by weight of ethylene-octene copolymer, 22 parts by weight of ethylene vinyl acetate resin, 3.5 parts by weight of triallyl isocyanate, 1.5 parts by weight of triphenyltriazine, 2.5 parts by weight of sodium dehydroacetate, and 1.5 parts by weight of potassium sorbate. The sheath (40) is prepared by extrusion using a twin-screw extruder at an extrusion temperature of 190°C. Reflective aluminum powder is then uniformly sprayed onto the outer surface of the sheath (40) to form a reflective aluminum powder layer (41) with a thickness of 0.2 mm.

[0047] Step 4: Preparation of the anti-corrosion layer. Mix 48 parts by weight of polyamide, 38 parts by weight of polyester, 10 parts by weight of nano alumina and 6 parts by weight of nano silica evenly, and apply the mixture evenly to the outer surface of the sheath (40) at a temperature of 25°C using a spraying process to prepare the anti-corrosion layer (50).

[0048] Step 5: Prepare the support frame. Woven the glass fiber fabric into a cylindrical tubular support frame (42), and fill the support frame (42) with a polyurethane buffer block (43), which is composed of 45 parts by weight of polyetheretherketone, 25 parts by weight of polyethersulfone, 15 parts by weight of nano-silica and 10 parts by weight of nano-alumina. Place the support frame (42) inside the sheath (40).

[0049] The conductor (10) obtained in step one is assembled sequentially with the insulation layer (30) obtained in step two and the sheath (40) obtained in step three, and combined with the anti-corrosion layer (50) obtained in step four and the support frame (42) obtained in step five to obtain the anti-corrosion and crack-resistant photovoltaic cable of Example 2.

[0050] Comparative Example 1

[0051] The preparation method of Example 1 is the same as that of Example 1, except that the nano-inorganic anti-cracking layer (20) is not coated on the outer surface of the ultra-flexible copper conductor in step 1. The remaining steps are exactly the same as those of Example 1, and the photovoltaic cable of Comparative Example 1 is obtained.

[0052] Comparative Example 2

[0053] The preparation method of Example 1 is the same as that of Example 1, except that the anti-corrosion layer (50) is not prepared in step four, and the outer surface of the sheath (40) is not coated with polyamide / polyester / nano alumina / nano silica anti-corrosion coating. The remaining steps are exactly the same as those of Example 1, and the photovoltaic cable of Comparative Example 2 is obtained.

[0054] Comparative Example 3

[0055] The preparation method of Example 1 is the same as that of Example 1, except that the anti-cracking composition is not added to the insulation layer (30) in step 2, and the ventilation groove (31) is not opened on the outer surface of the insulation layer (30). The rest of the steps are exactly the same as those of Example 1, and the photovoltaic cable of Comparative Example 3 is obtained.

[0056] Test Example 1

[0057] The photovoltaic cables prepared in Examples 1, 2, and Comparative Examples 1 to 3 were subjected to salt spray corrosion tests, crack resistance tests, mechanical property tests, weather resistance tests, and electrical property tests. The test methods are as described above, and the test results are shown in Tables 1 to 4.

[0058] Table 1. Comprehensive performance test results of photovoltaic cables in each embodiment and comparative example.

[0059] Example 1 0 0 100 ≥5000 0.0185 Example 2 0 0.5 100 ≥5000 0.0158 Comparative Example 1 3.2 8.5 75 ≥4500 0.0186 Comparative Example 2 18.6 35.2 90 ≥4800 0.0185 Comparative Example 3 1.5 4.8 55 ≥4200 0.0187

[0060] As shown in Table 1, the sheath corrosion area of ​​the cables in Examples 1 and 2 was 0 after 500h salt spray test (only 0.5% after 1000h in Example 2), the pass rate of bending test after thermal aging was 100%, the insulation resistance was ≥5000 MΩ·km, and the DC resistance of the conductor was 0.0185Ω / km and 0.0158Ω / km, respectively. This indicates that the multi-layer synergistic anti-corrosion and crack-resistant structure of the present invention has excellent corrosion resistance, crack resistance and electrical properties.

[0061] The pass rate of the bending test after thermal aging of Comparative Example 1 (lacking the nano-inorganic anti-cracking layer on the conductor surface) dropped to 75%, indicating that the nano-inorganic anti-cracking layer (20) on the conductor surface has an indispensable contribution to improving the overall anti-cracking performance of the cable.

[0062] The corrosion area of ​​Comparative Example 2 (lacking anti-corrosion layer) reached 18.6% after 500h of salt spray test and 35.2% after 1000h, indicating that the polyamide / polyester / nano alumina / nano silica anti-corrosion layer (50) is the key structure to block corrosive media.

[0063] The pass rate of the bending test of Comparative Example 3 (insulation layer without anti-cracking composition and without ventilation groove) was only 55%, indicating that the composite anti-cracking composition in the insulation layer and the setting of ventilation groove (31) have a synergistic effect on inhibiting the cracking of the insulation layer, which is unexpected.

[0064] Table 2. Mechanical property test results of each embodiment and comparative example

[0065] Example 1 18.5 320 92 88 pass Example 2 19.2 310 93 87 pass Comparative Example 1 17.8 305 85 78 pass Comparative Example 2 16.5 290 80 72 cracking Comparative Example 3 15.2 275 72 65 cracking

[0066] As shown in Table 2, the tensile strengths of Examples 1 and 2 were 18.5 MPa and 19.2 MPa, respectively, and the elongation at break were 320% and 310%, respectively, both superior to the comparative examples. After aging, the tensile strength retention rate exceeded 92%, and the elongation at break retention rate exceeded 87%, and both passed the low-temperature bending test, indicating that the cable of the present invention has good mechanical properties and low-temperature resistance. The low-temperature bending test of Comparative Examples 2 and 3 showed cracking, indicating that the lack of an anti-corrosion layer or the synergistic effect of the anti-cracking composition and the ventilation slot significantly reduces the cable's flexibility in low-temperature environments.

[0067] Table 3 Weather resistance test results of each embodiment and comparative example

[0068] Example 1 94 88 90 82 Level 0 Example 2 95 90 91 84 Level 0 Comparative Example 1 82 70 75 62 Level 1 Comparative Example 2 68 52 60 45 Level 2 Comparative Example 3 78 65 72 58 Level 1

[0069] As shown in Table 3, after 1000 hours of UV aging, the tensile strength retention rates of Examples 1 and 2 remained at 88% and 90%, respectively, and the powdering grade of the sheath surface was 0, indicating that the synergistic effect of the reflective aluminum powder layer and the anti-corrosion layer effectively reduced the photoaging rate of the sheath. In contrast, Comparative Example 2 (lacking an anti-corrosion layer) showed a tensile strength retention rate of only 52% and a powdering grade of 2 after 1000 hours of UV aging, demonstrating the important role of the anti-corrosion layer in inhibiting photoaging of the sheath.

[0070] Table 4. Changes in corrosion area of ​​sheath for each sample under different salt spray test times (%)

[0071] Example 1 0 0 0 0 0.2 Example 2 0 0 0.2 0.5 0.8 Comparative Example 1 1.5 3.2 5.8 8.5 12.3 Comparative Example 2 8.2 18.6 26.5 35.2 42.8 Comparative Example 3 0.8 1.5 2.8 4.8 7.5

[0072] As shown in Table 4, with the extension of salt spray test time, the corrosion area of ​​the sheaths in Examples 1 and 2 remained at an extremely low level, only 0.2% and 0.8% respectively after 1250 hours. In contrast, Comparative Example 2, which lacked an anti-corrosion layer, showed a corrosion area as high as 42.8% after 1250 hours, further verifying the long-term corrosion resistance of the polyamide / polyester / nano-alumina / nano-silica anti-corrosion layer. Comparative Example 1 lacked a nano-inorganic anti-cracking layer, and Comparative Example 3 lacked an anti-cracking composition and ventilation slots; their corrosion areas also increased significantly over time, indicating that the various structural layers of the present invention have a synergistic anti-corrosion and anti-cracking effect.

[0073] It is understood that the coating method of the nano-inorganic anti-cracking layer (20) is not limited to dip coating, but can also adopt coating processes commonly used in the field such as spraying and scraping. The number of ventilation slots (31) is not limited to 8, but can be adjusted to 6, 10 or 12 according to the cable specifications, as long as they are evenly and symmetrically arranged along the outer surface of the insulation layer (30). The shape of the support frame (42) is not limited to rectangular tubular or cylindrical tubular, but can also be designed as other tubular cross-section forms according to actual needs. The coating method of the anti-corrosion layer (50) is not limited to spraying, but can also adopt roller coating or brush coating processes.

Claims

1. A corrosion-resistant and crack-resistant photovoltaic cable, comprising a conductor, an insulation layer, and a sheath, characterized in that, The conductor is an ultra-flexible copper conductor, and its outer surface is provided with a nano-inorganic anti-cracking layer, which comprises aluminum silicate, alumina, silicon dioxide, and zinc oxide. The insulation layer is a low-smoke halogen-free irradiated cross-linked polyolefin insulation layer, which contains an anti-cracking composition comprising polyetheretherketone, polyethersulfone, nano-silica, and nano-alumina. The outer surface of the insulation layer is provided with ventilation grooves. The sheath is a vinyl chloride-ethylene copolymer sheath, and its outer surface is coated with a reflective aluminum powder layer. The sheath has a support frame made of glass fiber inside, which is filled with polyurethane buffer blocks. The outer surface of the sheath is also provided with an anti-corrosion layer, which comprises polyamide, polyester, nano-alumina, and nano-silica.

2. The anti-corrosion and crack-resistant photovoltaic cable according to claim 1, characterized in that, The nano-inorganic anti-cracking layer contains 70-80 parts by weight of aluminum silicate, 10-15 parts by weight of aluminum oxide, 5-10 parts by weight of silicon oxide, and 2-5 parts by weight of zinc oxide.

3. The anti-corrosion and crack-resistant photovoltaic cable according to claim 1, characterized in that, In the anti-cracking composition, the content of polyetheretherketone is 60-70 parts by weight, the content of polyethersulfone is 20-30 parts by weight, the content of nano-silica is 5-10 parts by weight, and the content of nano-alumina is 2-5 parts by weight.

4. The anti-corrosion and crack-resistant photovoltaic cable according to claim 1, characterized in that, The ventilation slot has a width of 0.5-1.0 mm, a depth of 0.3-0.5 mm, and a spacing of 1.0-1.5 mm between adjacent ventilation slots.

5. The anti-corrosion and crack-resistant photovoltaic cable according to claim 4, characterized in that, The number of ventilation slots is 8, and they are evenly and symmetrically arranged along the outer surface of the insulation layer.

6. The anti-corrosion and crack-resistant photovoltaic cable according to claim 1, characterized in that, The thickness of the reflective aluminum powder layer is 0.1-0.2 mm.

7. The anti-corrosion and crack-resistant photovoltaic cable according to claim 1, characterized in that, The anti-corrosion layer contains 40-50 parts by weight of polyamide, 30-40 parts by weight of polyester, 10-15 parts by weight of nano-alumina, and 5-10 parts by weight of nano-silica.

8. The anti-corrosion and crack-resistant photovoltaic cable according to claim 1, characterized in that, The support frame is a tubular structure.

9. A method for preparing a corrosion-resistant and crack-resistant photovoltaic cable, characterized in that, The process includes the following steps: (1) coating the outer surface of an ultra-flexible copper conductor with a nano-inorganic anti-cracking layer, wherein the nano-inorganic anti-cracking layer comprises aluminum silicate, aluminum oxide, silicon oxide and zinc oxide, to obtain a conductor with a surface coated with a nano-inorganic anti-cracking layer; (2) mixing a low-smoke halogen-free irradiated cross-linked polyolefin insulating material and an anti-cracking composition uniformly through a blending process, wherein the anti-cracking composition comprises polyetheretherketone, polyethersulfone, nano-silica and nano-alumina, to prepare an insulating layer, and opening ventilation grooves on the outer surface of the insulating layer; (3) mixing a vinyl chloride-ethylene copolymer material with reflective aluminum powder, and extruding the mixture. (3) Prepare a sheath by process and coat the outer surface of the sheath with a reflective aluminum powder layer; (4) Mix polyamide, polyester, nano alumina and nano silicon oxide evenly and coat them on the outer surface of the sheath by coating process to prepare an anti-corrosion layer; (5) Make a tubular support frame from glass fiber, fill the tubular support frame with polyurethane buffer block, and place the support frame inside the sheath; Assemble the conductor obtained in step (1) with the insulation layer obtained in step (2) and the sheath obtained in step (3) in sequence, and combine the anti-corrosion layer obtained in step (4) and the support frame obtained in step (5) to obtain an anti-corrosion and crack-resistant photovoltaic cable.

10. The method for preparing the corrosion-resistant and crack-resistant photovoltaic cable according to claim 9, characterized in that, In step (2), the temperature of the blending process is 150-160℃ and the stirring and mixing time is 15-20min.

11. The method for preparing the corrosion-resistant and crack-resistant photovoltaic cable according to claim 9, characterized in that, In step (3), the extrusion process uses a twin-screw extruder and the extrusion temperature is 180-190℃.

12. The method for preparing the corrosion-resistant and crack-resistant photovoltaic cable according to claim 9, characterized in that, In step (4), the coating process is carried out by spraying, and the coating temperature is 20-25℃.

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