Anti-oxidation and anti-ultraviolet photovoltaic cable and preparation method thereof

Abstract

The invention provides an anti-oxidation and anti-ultraviolet photovoltaic cable and a preparation method thereof. The anti-oxidation and anti-ultraviolet photovoltaic cable comprises a cable core, and the cable core is sequentially coated with a mineral flame-retardant layer, a high-temperature-resistant layer and an outer sheath layer; the cable core comprises at least one wire core, the wire core comprises a photovoltaic conductor layer, an inner insulating layer and an inner sheath layer which are sequentially arranged from inside to outside, the photovoltaic conductor layer is composed of a plurality of photovoltaic conductors, and the photovoltaic conductors are tinned copper flexible wires; the inner insulating layer is a cross-linked polyolefin insulating layer, and the inner sheath layer and the outer sheath layer are PVC sheath layers. And the inner insulating layer and the inner sheath layer are arranged in a tight fit manner. According to the anti-oxidation and anti-ultraviolet photovoltaic cable, layered design and cooperative protection are achieved, the inner insulating layer and the inner sheath layer are tightly attached, insulation failure caused by moisture or gas invasion is avoided, the mineral flame-retardant layer and the high-temperature-resistant layer resist external high temperature and flame, the environmental adaptability of the photovoltaic cable is improved, the outer sheath side is arranged on the outermost side, and the service life of the photovoltaic cable is prolonged. And the outdoor service life of the cable is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic cables, and particularly relates to an antioxidant and ultraviolet-resistant photovoltaic cable and a preparation method thereof. Background Art

[0002] Photovoltaic cables are cables specifically designed for solar power generation systems, mainly used to connect devices such as photovoltaic modules, inverters, and distribution cabinets, and transmit electrical energy between these devices. Photovoltaic cables usually consist of three layers, which are, from the inside to the outside, a conductor layer, an insulating layer, and a sheath layer. Among them, the conductor layer is often made of high-purity copper or tinned copper, which is the layer for current transmission; the insulating layer is wrapped outside the conductor layer to prevent the conductor layer from leaking electricity; the sheath layer is arranged outside the insulating layer and is in direct contact with the external environment, playing a role in protecting the internal insulating layer and conductor layer to improve the service life of the photovoltaic cable.

[0003] Photovoltaic cables are often installed in desert, Gobi, mountainous areas and other regions together with solar power generation systems. These regions have sufficient sunlight, which can provide sufficient energy sources for solar power generation. However, at the same time, the temperature in these regions is high and the ultraviolet radiation is strong, and the weather resistance requirements for photovoltaic cables are also relatively high.

[0004] In the prior art, the antioxidant and ultraviolet-resistant capabilities of photovoltaic cables are poor. After long-term light radiation, the cables are severely aged, and their properties such as tensile strength and elongation at break will be greatly reduced, which will further affect the service life of the cables. Summary of the Invention

[0005] The present invention provides an antioxidant and ultraviolet-resistant photovoltaic cable and a preparation method thereof to solve the problem of poor weather resistance of photovoltaic cables in the prior art.

[0006] The present invention provides an antioxidant and ultraviolet-resistant photovoltaic cable, which includes a cable core, and a mineral flame retardant layer, a high-temperature resistant layer, and an outer sheath layer are sequentially coated outside the cable core; the cable core includes at least one wire core, and the wire core includes a photovoltaic conductor layer, an inner insulating layer, and an inner sheath layer arranged in sequence from the inside to the outside. The photovoltaic conductor layer is composed of multiple photovoltaic conductors, and the photovoltaic conductors are tinned copper soft wires; the inner insulating layer is a cross-linked polyolefin insulating layer, and the inner sheath layer and the outer sheath layer are PVC sheath layers; the inner insulating layer and the inner sheath layer are closely and integrally arranged.

[0007] Optionally, the mineral flame retardant layer is formed by mixing magnesium oxide and apatite in a mass ratio of 4:1.

[0008] Optionally, the high-temperature resistant layer is formed by mixing polytetrafluoroethylene and zirconium silicate in a mass ratio of 2.5:1.

[0009] Optionally, the crosslinked polyolefin insulating layer is composed of the following raw materials in parts by weight: 85-90 parts of crosslinked polyolefin, 5-10 parts of crosslinking agent, 2-3 parts of initiator, 1 part of antioxidant, and 5-10 parts of auxiliary agent.

[0010] Optionally, the crosslinked polyolefin is polyethylene; the crosslinking agent is azodicarbonamide; the initiator is ammonium thiosulfate; the antioxidant is methyl caffeate; the auxiliary agent is a mixed preparation of modified nano-ceria and calcium lignosulfonate, and the mass ratio of modified nano-ceria to calcium lignosulfonate is 3:5.

[0011] Optionally, the modification steps of the modified nano-ceria are as follows:

[0012] 1): Take nano-ceria powder with a particle size between 50-100 nm and place it in a muffle furnace. Calcine it at 300 °C for 2 h, and then cool it to room temperature after calcination;

[0013] 2): Place the cooled nano-ceria in absolute ethanol for ultrasonic dispersion to obtain a suspension, where the mass ratio of nano-ceria to absolute ethanol is 1:10. The ultrasonic treatment time is 30 min, the power is 300 W, and the frequency is 40 kHz;

[0014] 3) Mix the silane coupling agent with a 90% ethanol aqueous solution, and adjust its pH to 4-5 with acetic acid, and then stir it evenly by magnetic stirring to obtain a hydrolysis solution;

[0015] 4): Dropwise add the suspension obtained in step 2) into the hydrolysis solution obtained in step 3). During the dropping, keep the temperature of the hydrolysis solution at 60 °C by water bath, and continuously stir and react for 2 h. The mass ratio of ceria to the silane coupling agent is 10:1;

[0016] 5): Centrifuge the reaction solution obtained in step 4), take the precipitate after centrifugation and wash it with absolute ethanol. After washing, place the precipitate in a vacuum drying oven and dry it at 80 °C for 12 h to obtain the modified nano-ceria.

[0017] Optionally, the PVC sheath layer is composed of the following raw materials in parts by weight: 50-60 parts of PVC, 20-25 parts of plasticizer, 5-10 parts of filler, 2-3 parts of lubricant, 1 part of antioxidant, and 3-5 parts of auxiliary agent.

[0018] Optionally, the plasticizer is glycerol rosinate; the filler is talc powder; the lubricant is polyethylene wax; the antioxidant is triphenyl phosphite; the auxiliary agent is a mixed preparation of zinc borate and phosphotungstic acid, and the mass ratio of zinc borate to phosphotungstic acid is 2:1.

[0019] The present invention also provides a preparation method for the above-mentioned antioxidant and ultraviolet-resistant photovoltaic cable, including the following steps:

[0020] S1: Prepare the raw materials for the cable core, mineral flame retardant layer, high temperature resistant layer and outer sheath layer, including tinned copper flexible wire, mineral flame retardant layer material, high temperature resistant layer material, cross-linked polyolefin insulation layer material and PVC sheath layer material;

[0021] S3: Ultrasonically clean the tinned copper flexible wire, and after removing the surface oxide layer, tension it and convey it forward at a constant speed;

[0022] S6: Premix the raw materials of the cross-linked polyolefin layer through a kneader, with a premixing temperature of 160°C and a time of 15 minutes;

[0023] S9: Premix the PVC sheath layer material through a kneader, with a premixing temperature of 120°C and a time of 10 minutes;

[0024] S12: Use a vacuum screw extruder to extrude the premixed cross-linked polyolefin layer raw materials and PVC sheath layer materials respectively. First, extrude the cross-linked polyolefin insulation material, irradiate it through an irradiation cross-linking machine to form an inner insulation layer, then cool it through a cold water sink and then extrude the PVC sheath material through an extrusion screw, and coat it outside the inner insulation layer to form an inner sheath layer;

[0025] S15: On the outside of the cable with the inner sheath layer formed, sequentially coat a mineral flame retardant layer and a high temperature resistant layer, and finally extrude and coat an outer sheath layer through a screw extruder;

[0026] S18: After the coating of each layer is completed, perform air cooling and shaping, then detect, wind and store.

[0027] Optionally, when coating the mineral flame retardant layer in S15, use an electrostatic spraying process to spray it on the outside of the inner sheath layer, and perform infrared curing after spraying; the high temperature resistant layer is coated on the outside of the mineral flame retardant layer by a wrapping process.

[0028] The beneficial effects of the antioxidant and anti-ultraviolet photovoltaic cable provided by the present invention are as follows: 1. The cable is designed in layers and provides coordinated protection. Among them, the tinned copper flexible wire is used as the conductor, which has strong antioxidant performance. The tin layer covers the copper surface, isolating oxygen and moisture, inhibiting the oxidation of copper to produce copper oxide, and avoiding the increase of resistance. The inner insulation layer and the inner sheath layer are closely arranged, and the two eliminate the interlayer gap through co-extrusion, avoiding insulation failure caused by the intrusion of moisture or gas. The mineral flame retardant layer and the high temperature resistant layer resist external high temperature and fire, improving the environmental adaptability of the photovoltaic cable. The outer sheath is arranged on the outermost side, with anti-ultraviolet, acid and alkali corrosion resistance, and extends the outdoor service life of the cable.

[0029] 2. The mineral flame retardant layer is compounded with magnesium oxide and apatite, and the high temperature resistant layer is compounded with polytetrafluoroethylene and zirconium silicate. The two protective layers work together to improve the weather resistance of the cable in high temperature environments.

[0030] 3. The cross-linked polyolefin insulation layer uses polyethylene as the matrix. Azodicarbonamide and ammonium thiosulfate act synergistically to promote the cross-linking of polyethylene, improving the heat resistance and mechanical strength of the product. Methyl caffeate inhibits the oxidative degradation of cable materials and delays material aging. Calcium lignosulfonate and nano-ceria act synergistically to inhibit ultraviolet and thermal oxidation, increasing the service life of the cable.

[0031] 4. The PVC sheath layer uses PVC as the matrix. Glycerol ester of rosin improves the flexibility of the PVC sheath layer. Talcum powder increases the tensile strength and wear resistance of the PVC sheath layer. Zinc borate and phosphotungstic acid act synergistically to improve the high-temperature resistance and flame retardancy of the PVC sheath layer. Brief Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 It is a schematic structural diagram of the photovoltaic cable provided by the embodiment of the present invention;

[0034] Figure 2 It is a schematic structural diagram of the core wire in the photovoltaic cable provided by the embodiment of the present invention;

[0035] Description of the reference numerals: 1 - cable core, 2 - mineral flame retardant layer, 3 - high-temperature resistant layer, 4 - outer sheath layer, 11 - core wire, 12 - photovoltaic conductor layer, 13 - inner insulation layer, 14 - inner sheath layer, 15 - photovoltaic conductor. Detailed Embodiments

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following clearly and completely describes the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts also belong to the scope of protection of the present invention.

[0037] Such as Figure 1 Iand Figure 2As shown, the present invention provides an antioxidant and UV-resistant photovoltaic cable, comprising a cable core 1, which is sequentially coated with a mineral flame-retardant layer 2, a high-temperature resistant layer 3 and an outer sheath layer 4; the cable core 1 comprises at least one wire core 11, which comprises a photovoltaic conductor layer 12, an inner insulating layer 13 and an inner sheath layer 14 arranged sequentially from the inside to the outside, the photovoltaic conductor layer 12 is composed of a plurality of photovoltaic conductors 15, and the photovoltaic conductors 15 are tinned copper soft wires; the inner insulating layer 13 is a cross-linked polyolefin insulating layer, and the inner sheath layer 14 and the outer sheath layer 4 are PVC sheath layers; the inner insulating layer 13 and the inner sheath layer 14 are tightly and closely arranged.

[0038] The anti-oxidation and anti-UV photovoltaic cable has a layered design and coordinated protection. The tinned copper soft wire is used as a conductor, which has strong anti-oxidation properties. The tin layer covers the copper surface, isolating oxygen and moisture, inhibiting the oxidation of copper into copper oxide, and avoiding increased resistance. The inner insulation layer 13 and the inner sheath layer 14 are tightly fitted together. The two are co-extruded to eliminate the gap between the layers, preventing moisture or gas intrusion from causing insulation failure. The mineral flame retardant layer and the high-temperature resistant layer resist external high temperatures and flames, improving the environmental adaptability of the photovoltaic cable. The outer sheath side is set on the outermost side, which is resistant to UV, acid and alkali corrosion, and extends the outdoor service life of the cable.

[0039] Furthermore, the mineral flame retardant layer 2 is formed by mixing magnesium oxide and apatite in a mass ratio of 4:1.

[0040] Magnesium oxide is stable at high temperatures, and its fire-resistant insulating properties allow it to maintain its structural integrity in high-temperature environments. Apatite decomposes when heated to produce oxyacids, which combine with the remaining layer material to form a dense covering that insulates against heat.

[0041] Furthermore, the high temperature resistant layer 3 is formed by mixing polytetrafluoroethylene and zirconium silicate in a mass ratio of 2.5:1.

[0042] Polytetrafluoroethylene is resistant to high-temperature decomposition, and zirconium silicate has a high melting point and hardness, which can not only resist high-temperature decomposition but also enhance the mechanical strength of the high-temperature resistant layer 3.

[0043] Furthermore, the cross-linked polyolefin insulation layer is composed of the following raw materials in parts by weight: 85-90 parts cross-linked polyolefin, 5-10 parts cross-linking agent, 2-3 parts initiator, 1 part antioxidant, and 5-10 parts auxiliary agent. Furthermore, the cross-linked polyolefin is polyethylene; the cross-linking agent is azodicarbonamide; the initiator is ammonium thiosulfate; the antioxidant is methyl caffeate; and the auxiliary agent is a mixture of modified nano-cerium oxide and calcium lignin sulfonate, wherein the mass ratio of modified nano-cerium oxide to calcium lignin sulfonate is 3:5.

[0044] The common function of azodicarbonamide is to be used as a foaming agent. In the present invention, using azodicarbonamide in combination with ammonium thiosulfate can promote the crosslinking of polyethylene, improve the crosslinking efficiency, and thereby enhance the heat resistance and mechanical strength of photovoltaic cables. The polyphenol structure of methyl caffeate can capture free radicals and then block the oxidation chain reaction, thereby inhibiting the oxidative degradation of cable materials and delaying material aging. Among the additives, nano-ceria has high ultraviolet resistance. The polyphenols and sulfonic acid groups in calcium lignosulfonate can bind to polyethylene through hydrogen bonds, delaying thermal decomposition. The two act synergistically to inhibit ultraviolet and thermal oxidation, and improve the service life of the cable.

[0045] Furthermore, the modification steps of the modified nano-ceria are as follows:

[0046] 1): Take nano-ceria powder with a particle size between 50 - 100 nm and place it in a muffle furnace. Calcine it at 300 °C for 2 h, and then cool it to room temperature after calcination;

[0047] 2): Place the cooled nano-ceria in absolute ethanol for ultrasonic dispersion to obtain a suspension. The mass ratio of nano-ceria to absolute ethanol is 1:10. The ultrasonic treatment time is 30 min, the power is 300 W, and the frequency is 40 kHz;

[0048] 3) Mix the silane coupling agent with a 90% ethanol aqueous solution, and adjust its pH to 4 - 5 with acetic acid, and then stir it evenly by magnetic stirring to obtain a hydrolysis solution;

[0049] 4): Slowly add the suspension obtained in step 2) dropwise to the hydrolysis solution obtained in step 3). During the dropping, keep the temperature of the hydrolysis solution at 60 °C by water bath, and continuously stir and react for 2 h. The mass ratio of ceria to the silane coupling agent is 10:1;

[0050] 5): Centrifuge the reaction solution obtained in step 4). After centrifugation, take the precipitate and wash it with absolute ethanol. After washing, place the precipitate in a vacuum drying oven and dry it at 80 °C for 12 h to obtain the modified nano-ceria.

[0051] Furthermore, the PVC sheath layer is composed of the following raw materials in parts by weight: 50 - 60 parts of PVC, 20 - 25 parts of plasticizer, 5 - 10 parts of filler, 2 - 3 parts of lubricant, 1 part of antioxidant, and 3 - 5 parts of auxiliary agent. Further, the plasticizer is glycerol rosinate; the filler is talc powder; the lubricant is polyethylene wax; the antioxidant is triphenyl phosphite; the auxiliary agent is a mixed preparation of zinc borate and phosphotungstic acid, and the mass ratio of zinc borate to phosphotungstic acid is 2:1.

[0052] In the plasticizer rosin glyceride, it binds to the PVC molecular chain through hydrogen bonds, inhibits the volatilization of the plasticizer, improves the flexibility of the PVC sheath layer, and reduces the migration rate of the plasticizer. The flaky structure of talcum powder is dispersed in the PVC matrix, enhancing the tensile strength and wear resistance of the PVC sheath layer. In the auxiliary agent, zinc borate decomposes when heated. When the PVC sheath layer is in a high-temperature combustion environment, zinc borate decomposes, releasing crystal water and absorbing a large amount of heat energy during the decomposition process, thereby reducing the temperature of the polymer surface and inhibiting combustion. At the same time, the decomposition product boron trioxide of zinc borate will cover the PVC sheath layer, further isolating the air and thus inhibiting combustion. Phosphotungstic acid is a strong proton acid. During high-temperature combustion, it can react with the PVC matrix to form a dense carbon layer by carbonization. The carbon layer covers the surface of the material, blocking the contact between oxygen and the unburned body, thereby inhibiting the combustion reaction. Boric acid is released from phosphotungstic acid to form a glassy barrier layer, inhibiting the spread of the flame.

[0053] The present invention also provides a preparation method for the above antioxidant and ultraviolet-resistant photovoltaic cable, which includes the following steps:

[0054] S1: Prepare the raw materials for the cable core 1, the mineral flame-retardant layer 2, the high-temperature-resistant layer 3, and the outer sheath layer 4, including tinned copper soft wire, mineral flame-retardant layer material, high-temperature-resistant layer material, cross-linked polyolefin insulation layer material, and PVC sheath layer material;

[0055] S2: Ultrasonically clean the tinned copper soft wire, remove the surface oxide layer, and then tension and convey it forward at a constant speed;

[0056] S3: Premix the raw materials of the cross-linked polyolefin layer through a kneader, with a premixing temperature of 160 °C and a time of 15 min;

[0057] S4: Premix the PVC sheath layer material through a kneader, with a premixing temperature of 120 °C and a time of 10 min;

[0058] S5: Use a vacuum screw extruder to extrude the premixed cross-linked polyolefin layer raw materials and PVC sheath layer materials respectively. First, extrude the cross-linked polyolefin insulation material, irradiate it through an irradiation cross-linking machine to form the inner insulation layer 13, then cool it through a cold water sink and then extrude the PVC sheath material through an extrusion screw, and coat it outside the inner insulation layer 13 to form the inner sheath layer 14;

[0059] S6: Sequentially coat the mineral flame-retardant layer 2 and the high-temperature-resistant layer 3 on the outside of the cable with the inner sheath layer 14 formed, and finally extrude and coat the outer sheath layer 14 through a screw extruder;

[0060] S7: After the coating of each layer is completed, perform air cooling for shaping, then detect, wind up, and store.

[0061] Further, in S5, when coating the mineral flame retardant layer 2, an electrostatic spraying process is used to spray it on the outer side of the inner sheath layer 14, and infrared curing can be carried out after spraying; the high-temperature resistant layer 3 is coated on the outer side of the mineral flame retardant layer by a wrapping process.

[0062] The following further describes the present invention in detail with specific embodiments:

[0063] Embodiment 1

[0064] An antioxidant and ultraviolet-resistant photovoltaic cable includes a cable core 1, and the cable core 1 is sequentially coated with a mineral flame retardant layer 2, a high-temperature resistant layer 3, and an outer sheath layer 4; the cable core 1 includes a wire core 11, and the wire core 11 includes a photovoltaic conductor layer 12, an inner insulating layer 13, and an inner sheath layer 14 arranged in sequence from the inside to the outside. The photovoltaic conductor layer 12 is composed of multiple photovoltaic conductors 15, and the photovoltaic conductor 15 is a tinned copper soft wire; the inner insulating layer 13 is a cross-linked polyolefin insulating layer, and the inner sheath layer 14 and the outer sheath layer 4 are PVC sheath layers.

[0065] Among them, the mineral flame retardant layer 2 is formed by mixing magnesium oxide and apatite in a mass ratio of 4:1. The high-temperature resistant layer 3 is formed by mixing polytetrafluoroethylene and zirconium silicate in a mass ratio of 2.5:1.

[0066] The cross-linked polyolefin insulating layer includes the following raw materials in parts by weight: 85 parts of cross-linked polyolefin (polyethylene), 5 parts of cross-linking agent (azodicarbonamide), 2 parts of initiator (ammonium thiosulfate), 1 part of antioxidant (methyl caffeate), and 5 parts of auxiliary agent (modified nano-ceria and calcium lignosulfonate with a mass ratio of 3:5).

[0067] The modification method of nano-ceria in the auxiliary agent is as follows: 1): Take nano-ceria powder with a particle size between 50-100nm and place it in a muffle furnace, calcine it at 300°C for 2h, and cool it to room temperature after calcination;

[0068] 2): Place the cooled nano-ceria in absolute ethanol for ultrasonic dispersion to obtain a suspension, where the mass ratio of nano-ceria to absolute ethanol is 1:10, the ultrasonic treatment time is 30min, the power is 300W, and the frequency is 40kHz;

[0069] 3) Mix the silane coupling agent with a 90% ethanol aqueous solution, and adjust its pH to 4-5 with acetic acid, and then stir it evenly by magnetic stirring to obtain a hydrolysis solution;

[0070] 4): Dropwise add the suspension obtained in step 2) into the hydrolysis solution obtained in step 3), and keep the temperature of the hydrolysis solution at 60°C by water bath during dropping, and continuously stir and react for 2h. The mass ratio of ceria to the silane coupling agent is 10:1;

[0071] 5): Centrifuge the reaction solution obtained in step 4), take the precipitate after centrifugation and wash it with absolute ethanol. After washing, place the precipitate in a vacuum drying oven and dry it at 80 °C for 12 h to obtain modified nano-ceria.

[0072] The PVC sheath layer comprises raw materials in the following parts by weight: 50 parts of PVC, 20 parts of plasticizer (rosin glyceride), 5 parts of filler (talc powder), 2 parts of lubricant (polyethylene wax), 1 part of antioxidant (triphenyl phosphite), and 3 parts of auxiliary agent (zinc borate and phosphotungstic acid with a mass ratio of 2:1).

[0073] A preparation method of an antioxidant and anti-ultraviolet photovoltaic cable comprises the following steps:

[0074] S1: Prepare the raw materials of the cable core 1, the mineral flame-retardant layer 2, the high-temperature resistant layer 3, and the outer sheath layer 4 according to the above requirements;

[0075] S2: Ultrasonically clean the tinned copper soft wire, remove the surface oxide layer, and then tension and uniformly convey it forward;

[0076] S3: Premix the raw materials of the crosslinked polyolefin layer through a mixer, with a premixing temperature of 160 °C and a time of 15 min;

[0077] S4: Premix the PVC sheath layer materials through a mixer, with a premixing temperature of 120 °C and a time of 10 min;

[0078] S5: Use a vacuum screw extruder to extrude the premixed crosslinked polyolefin layer raw materials and PVC sheath layer materials respectively. First, extrude the crosslinked polyolefin insulating material, irradiate it through an irradiation crosslinking machine to form the inner insulating layer 13, then cool it through a cold water sink and then extrude the PVC sheath material through an extrusion screw, and coat it outside the inner insulating layer 13 to form the inner sheath layer 14;

[0079] S6: Coat the mineral flame-retardant layer 2 on the outer side of the cable with the formed inner sheath layer 14 through an electrostatic spraying process. Before spraying, dry the magnesium oxide and apatite powder to make its humidity ≤ 1%, and perform infrared curing after spraying. The high-temperature resistant layer 3 is coated on the outer side of the mineral flame-retardant layer 2 through a winding process, and finally, the outer sheath layer 14 is extruded and coated through a screw extruder, and the extrusion process is the same as that in step S5.

[0080] S7: After the coating of each layer is completed, perform air cooling and shaping, then detect, wind up and store.

[0081] Example 2

[0082] An antioxidant and ultraviolet-resistant photovoltaic cable includes a cable core 1, and is successively coated with a mineral flame-retardant layer 2, a high-temperature-resistant layer 3, and an outer sheath layer 4 outside the cable core 1; the cable core 1 includes a single wire core 11, and the wire core 11 includes a photovoltaic conductor layer 12, an inner insulation layer 13, and an inner sheath layer 14 arranged in sequence from inside to outside. The photovoltaic conductor layer 12 is composed of multiple photovoltaic conductors 15, and the photovoltaic conductors 15 are tinned copper soft wires; the inner insulation layer 13 is a cross-linked polyolefin insulation layer, and the inner sheath layer 14 and the outer sheath layer 4 are PVC sheath layers.

[0083] Among them, the mineral flame-retardant layer 2 is formed by mixing magnesium oxide and apatite in a mass ratio of 4:1. The high-temperature-resistant layer 3 is formed by mixing polytetrafluoroethylene and zirconium silicate in a mass ratio of 2.5:1.

[0084] The cross-linked polyolefin insulation layer includes the following raw materials in parts by weight: 90 parts of cross-linked polyolefin (polyethylene), 10 parts of cross-linking agent (azodicarbonamide), 3 parts of initiator (ammonium thiosulfate), 1 part of antioxidant (methyl caffeate), and 10 parts of auxiliary agent (modified nano-ceria and calcium lignosulfonate with a mass ratio of 3:5).

[0085] The modification method of nano-ceria in the auxiliary agent is as follows: 1): Take nano-ceria powder with a particle size between 50-100nm and place it in a muffle furnace, calcine it at 300°C for 2h, and cool it to room temperature after calcination;

[0086] 2): Place the cooled nano-ceria in absolute ethanol for ultrasonic dispersion to obtain a suspension, where the mass ratio of nano-ceria to absolute ethanol is 1:10, the ultrasonic treatment time is 30min, the power is 300W, and the frequency is 40kHz;

[0087] 3) Mix the silane coupling agent with a 90% ethanol aqueous solution, and adjust its pH to 4-5 with acetic acid, and then stir it evenly by magnetic stirring to obtain a hydrolysis solution;

[0088] 4): Slowly add the suspension obtained in step 2) dropwise to the hydrolysis solution obtained in step 3), and keep the temperature of the hydrolysis solution at 60°C by water bath during dropping, and continuously stir and react for 2h. The mass ratio of cerium oxide to the silane coupling agent is 10:1;

[0089] 5): Centrifuge the reaction solution obtained in step 4), take the precipitate after centrifugation and wash it with absolute ethanol, and then place the precipitate in a vacuum drying oven and dry it at 80°C for 12h to obtain the modified nano-ceria.

[0090] The PVC sheath layer includes the following raw materials in parts by weight: 60 parts of PVC, 25 parts of plasticizer (glycerol ester of rosin), 10 parts of filler (talc powder), 3 parts of lubricant (polyethylene wax), 1 part of antioxidant (triphenyl phosphite), and 5 parts of auxiliary agent (zinc borate and phosphotungstic acid with a mass ratio of 2:1).

[0091] A preparation method of an antioxidant and ultraviolet-resistant photovoltaic cable, comprising the following steps:

[0092] S1: Prepare the raw materials of the cable core 1, the mineral flame-retardant layer 2, the high-temperature-resistant layer 3 and the outer sheath layer 4 according to the above requirements;

[0093] S2: Ultrasonically clean the tinned copper soft wire, remove the surface oxide layer, and then tension and convey it forward at a constant speed;

[0094] S3: Premix the raw materials of the crosslinked polyolefin layer through a kneader, with a premixing temperature of 160 °C and a time of 15 min;

[0095] S4: Premix the PVC sheath layer material through a kneader, with a premixing temperature of 120 °C and a time of 10 min;

[0096] S5: Use a vacuum screw extruder to extrude the premixed crosslinked polyolefin layer raw materials and PVC sheath layer materials respectively. First, extrude the crosslinked polyolefin insulating material, irradiate it through an irradiation crosslinking machine to form the inner insulating layer 13, then cool it through a cold water sink and then extrude the PVC sheath material through an extrusion screw, and coat it outside the inner insulating layer 13 to form the inner sheath layer 14;

[0097] S6: Coat the mineral flame-retardant layer 2 on the outside of the cable with the formed inner sheath layer 14 through an electrostatic spraying process. Before spraying, dry the magnesium oxide and apatite powder to make its humidity ≤ 1%, and perform infrared curing after spraying. The high-temperature-resistant layer 3 is coated on the outside of the mineral flame-retardant layer 2 through a winding process, and finally the outer sheath layer 14 is extruded and coated through a screw extruder, and the extrusion process is the same as that in step S5.

[0098] S7: After the coating of each layer is completed, perform air cooling for shaping, then detect, wind and store.

[0099] Example 3

[0100] An antioxidant and ultraviolet-resistant photovoltaic cable includes a cable core 1, and the cable core 1 is sequentially coated with a mineral flame-retardant layer 2, a high-temperature-resistant layer 3 and an outer sheath layer 4; the cable core 1 includes a wire core 11, and the wire core 11 includes a photovoltaic conductor layer 12, an inner insulating layer 13 and an inner sheath layer 14 arranged in sequence from the inside to the outside. The photovoltaic conductor layer 12 is composed of multiple photovoltaic conductors 15, and the photovoltaic conductor 15 is a tinned copper soft wire; the inner insulating layer 13 is a crosslinked polyolefin insulating layer, and the inner sheath layer 14 and the outer sheath layer 4 are PVC sheath layers.

[0101] Among them, the mineral flame-retardant layer 2 is formed by mixing magnesium oxide and apatite in a mass ratio of 4:1. The high-temperature-resistant layer 3 is formed by mixing polytetrafluoroethylene and zirconium silicate in a mass ratio of 2.5:1.

[0102] The crosslinked polyolefin insulating layer comprises raw materials in the following parts by weight: 87 parts of crosslinked polyolefin (polyethylene), 7 parts of crosslinking agent (azodicarbonamide), 2 parts of initiator (ammonium thiosulfate), 1 part of antioxidant (methyl caffeate), and 8 parts of auxiliary agent (modified nano-ceria and calcium lignosulfonate with a mass ratio of 3:5).

[0103] The modification method of nano-ceria in the auxiliary agent is as follows: 1): Take nano-ceria powder with a particle size between 50 - 100 nm and place it in a muffle furnace, calcine it at 300 °C for 2 h, and cool it to room temperature after calcination;

[0104] 2): Place the cooled nano-ceria in absolute ethanol for ultrasonic dispersion to obtain a suspension, where the mass ratio of nano-ceria to absolute ethanol is 1:10, the ultrasonic treatment time is 30 min, the power is 300 W, and the frequency is 40 kHz;

[0105] 3) Mix the silane coupling agent with a 90% ethanol aqueous solution, adjust its pH to 4 - 5 with acetic acid, and then stir it evenly by magnetic stirring to obtain a hydrolysis solution;

[0106] 4): Slowly add the suspension obtained in step 2) dropwise to the hydrolysis solution obtained in step 3), keep the temperature of the hydrolysis solution at 60 °C by water bath during dropping, and continuously stir and react for 2 h. The mass ratio of ceria to the silane coupling agent is 10:1;

[0107] 5): Centrifuge the reaction solution obtained in step 4), take the precipitate after centrifugation and wash it with absolute ethanol, then place the precipitate in a vacuum drying oven and dry it at 80 °C for 12 h to obtain the modified nano-ceria.

[0108] The PVC sheath layer comprises raw materials in the following parts by weight: 55 parts of PVC, 23 parts of plasticizer (glycerol ester of rosin), 7 parts of filler (talc powder), 3 parts of lubricant (polyethylene wax), 1 part of antioxidant (triphenyl phosphite), and 4 parts of auxiliary agent (zinc borate and phosphotungstic acid with a mass ratio of 2:1).

[0109] A preparation method of an antioxidant and ultraviolet-resistant photovoltaic cable comprises the following steps:

[0110] S1: Prepare the raw materials of the cable core 1, the mineral flame-retardant layer 2, the high-temperature-resistant layer 3, and the outer sheath layer 4 according to the above requirements;

[0111] S2: Ultrasonically clean the tinned copper soft wire, remove the surface oxide layer, and then tension and convey it forward at a constant speed;

[0112] S3: Premix the raw materials of the crosslinked polyolefin layer through a kneader, with a premixing temperature of 160 °C and a time of 15 min;

[0113] S4: Premix the PVC sheath layer material using a kneader at a premixing temperature of 120°C for 10 minutes;

[0114] S5: Use a vacuum screw extruder to perform extrusion operations on the premixed cross-linked polyolefin layer raw material and the PVC sheath layer material respectively. First, extrude the cross-linked polyolefin insulating material, which forms the inner insulating layer 13 after being irradiated by an irradiation cross-linking machine, and then after being cooled in a cold water sink, extrude the PVC sheath material through an extrusion screw and wrap it outside the inner insulating layer 13 to form the inner sheath layer 14;

[0115] S6: Coat the mineral flame-retardant layer 2 on the outside of the cable with the inner sheath layer 14 formed by electrostatic spraying. Before spraying, dry the magnesium oxide and apatite powder to make its humidity ≤ 1%, and perform infrared curing after spraying. The high-temperature resistant layer 3 is coated on the outside of the mineral flame-retardant layer 2 by a winding process, and finally, the outer sheath layer 14 is extruded and coated through a screw extruder. The extrusion process is the same as the steps in S5.

[0116] S7: After the coating of each layer is completed, perform air cooling and shaping, then detect, wind up and store.

[0117] The properties of the antioxidant and ultraviolet-resistant cables obtained in Examples 1-3 are shown in Table 1:

[0118] Table 1

[0119]

[0120] Comparative Example 1

[0121] The difference between Comparative Example 1 and Example 1 is only that no additives are added to the raw material for forming the cross-linked polyolefin insulating layer.

[0122] Comparative Example 2

[0123] The difference between Comparative Example 2 and Example 1 is only that the cross-linking agent in the raw material for forming the cross-linked polyolefin insulating layer is diisopropylbenzene peroxide and the initiator is benzoyl peroxide.

[0124] Comparative Example 3

[0125] The difference between Comparative Example 2 and Example 1 is only that the antioxidant in the raw material for forming the cross-linked polyolefin insulating layer is antioxidant CA.

[0126] Comparative Example 4

[0127] The difference between Comparative Example 4 and Example 1 is only that no auxiliary agents are added to the raw material for forming the PVC sheath layer.

[0128] Comparative Example 5

[0129] The difference between Comparative Example 5 and Example 1 is only that the plasticizer in the raw material constituting the PVC sheath layer is methyl phthalate.

[0130] The performance test items, standards and methods of the photovoltaic cables obtained in Comparative Examples 1-5 are the same as the content in Table 1, and the specific indicators are shown in Table 2:

[0131] Table 2:

[0132]

[0133] It can be seen from the comparison of Table 1 and Table 2 that the additives (modified nano-ceria and calcium lignosulfonate) have great influences on both the antioxidant performance and the anti-ultraviolet performance of the photovoltaic cable. When no additives were used in Comparative Example 1, all indicators decreased significantly. Azodicarbonamide, ammonium thiosulfate and methyl caffeate have great influences on the thermal aging performance of the photovoltaic cable. After replacing with conventional crosslinking agents, initiators and antioxidants in Comparative Examples 2 and 3, the performance of two indicators, namely the change rate of tensile strength after hot air aging and the change rate of elongation at break after hot air aging, decreased significantly. Referring to Comparative Examples 4 and 5, it can be seen that the auxiliary agents (zinc borate and phosphotungstic acid), and glycerol ester of rosin have great influences on both the antioxidant performance and the anti-ultraviolet performance of the photovoltaic cable.

[0134] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An antioxidant and UV-resistant photovoltaic cable, characterized in that, It includes a cable core (1), and a mineral flame retardant layer (2), a high temperature resistant layer (3) and an outer sheath layer (4) are sequentially coated outside the cable core (1); The cable core (1) includes at least one wire core (11), the wire core (11) includes a photovoltaic conductor layer (12), an inner insulating layer (13) and an inner sheath layer (14) which are arranged in sequence from inside to outside. The photovoltaic conductor layer (12) is composed of a plurality of photovoltaic conductors (15), and the photovoltaic conductors (15) are tinned copper soft wires; The inner insulating layer (13) is a cross-linked polyolefin insulating layer, and the inner sheath layer (14) and the outer sheath layer (4) are PVC sheath layers; The inner insulating layer (13) and the inner sheath layer (14) are closely and integrally arranged.

2. The antioxidant and ultraviolet-resistant photovoltaic cable according to claim 1, wherein The mineral flame retardant layer (2) is formed by mixing magnesium oxide and apatite in a mass ratio of 4:

1.

3. The antioxidant and ultraviolet-resistant photovoltaic cable according to claim 1, wherein The high temperature resistant layer (3) is formed by mixing polytetrafluoroethylene and zirconium silicate in a mass ratio of 2.5:

1.

4. The antioxidant and ultraviolet-resistant photovoltaic cable according to claim 1, characterized in that, The cross-linked polyolefin insulating layer is composed of the following raw materials in parts by weight: 85-90 parts of cross-linked polyolefin, 5-10 parts of cross-linking agent, 2-3 parts of initiator, 1 part of antioxidant, and 5-10 parts of auxiliary agent.

5. The antioxidant and ultraviolet-resistant photovoltaic cable according to claim 4, wherein The cross-linked polyolefin is polyethylene; The cross-linking agent is azodicarbonamide; The initiator is ammonium thiosulfate; The antioxidant is methyl caffeate; The auxiliary agent is a mixed preparation of modified nano-ceria and calcium lignosulfonate, and the mass ratio of modified nano-ceria to calcium lignosulfonate is 3:

5.

6. The antioxidant and UV-resistant photovoltaic cable according to claim 5, wherein The modification steps of the modified nano-ceria are as follows: 1): Take nano-ceria powder with a particle size between 50-100nm and place it in a muffle furnace, calcine it at 300°C for 2h, and cool it to room temperature after calcination; 2): Place the cooled nano-ceria in absolute ethanol for ultrasonic dispersion to obtain a suspension, where the mass ratio of nano-ceria to absolute ethanol is 1:10, the ultrasonic treatment time is 30min, the power is 300W, and the frequency is 40kHz; 3) Mix the silane coupling agent with a 90% ethanol aqueous solution, adjust its pH to 4-5 with acetic acid, and then stir it evenly by magnetic stirring to obtain a hydrolysis solution; 4): Dropwise add the suspension obtained in step 2) into the hydrolysis solution obtained in step 3), and keep the temperature of the hydrolysis solution at 60°C by water bath during dropping, and continuously stir and react for 2h. The mass ratio of cerium oxide to silane coupling agent is 10:1; 5): Centrifuge the reaction solution obtained in step 4), take the precipitate after centrifugation and wash it with absolute ethanol, and then place the precipitate in a vacuum drying oven and dry it at 80°C for 12h to obtain the modified nano-ceria.

7. The antioxidant and ultraviolet-resistant photovoltaic cable according to claim 1, wherein The PVC sheath layer is composed of the following raw materials in parts by weight: 50-60 parts of PVC, 20-25 parts of plasticizer, 5-10 parts of filler, 2-3 parts of lubricant, 1 part of antioxidant, and 3-5 parts of auxiliary agent.

8. The antioxidant and ultraviolet-resistant photovoltaic cable according to claim 7, characterized in that, The plasticizer is rosin glyceride; The filler is talc powder; The lubricant is polyethylene wax; The antioxidant is triphenyl phosphite; The auxiliary agent is a mixed preparation of zinc borate and phosphotungstic acid, and the mass ratio of zinc borate to phosphotungstic acid is 2:

1.

9. A preparation method of the antioxidant and ultraviolet-resistant photovoltaic cable according to any one of claims 1-8, characterized in that, It includes the following steps: S1: Prepare the raw materials for the cable core (1), mineral flame retardant layer (2), high temperature resistant layer (3) and outer sheath layer (4), including tinned copper flexible wire, mineral flame retardant layer material, high temperature resistant layer material, cross-linked polyolefin insulation layer material and PVC sheath layer material; S2: Ultrasonically clean the tinned copper flexible wire, and after removing the surface oxide layer, tension and uniformly convey it forward; S3: Premix the cross-linked polyolefin layer raw materials through a kneader, with a premixing temperature of 160 °C and a time of 15 min; S4: Premix the PVC sheath layer material through a kneader, with a premixing temperature of 120 °C and a time of 10 min; S5: Use a vacuum screw extruder to perform extrusion operations on the premixed cross-linked polyolefin layer raw materials and PVC sheath layer materials respectively. First, extrude the cross-linked polyolefin insulation material, irradiate it through an irradiation cross-linking machine to form an inner insulation layer (13), then cool it through a cold water sink and then extrude the PVC sheath material through an extrusion screw, and coat it outside the inner insulation layer (13) to form an inner sheath layer (14); S6: On the outside of the cable with the inner sheath layer (14) formed, sequentially coat the mineral flame retardant layer (2) and the high temperature resistant layer (3), and finally extrude and coat the outer sheath layer (14) through a screw extruder; S7: After the coating of each layer is completed, perform air cooling and shaping, then detect, wind up and store.

10. The preparation method of the antioxidant and ultraviolet-resistant photovoltaic cable according to claim 9, characterized in that, In step S5, when coating the mineral flame retardant layer (2), it is sprayed on the outside of the inner sheath layer (14) by an electrostatic spraying process, and infrared curing can be carried out after spraying; The high temperature resistant layer (3) is coated on the outside of the mineral flame retardant layer by a wrapping process.

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