A low temperature resistant photovoltaic branch cable and preparation method thereof

Abstract

The invention relates to the technical field of cables, and specifically to a low-temperature resistant photovoltaic branch cable and a preparation method thereof. The cable comprises an outer sheath, an insulation layer, a wrapping layer and a cable core, wherein the cable core comprises an inner sheath, a shielding layer, an insulating layer and a conductor; the outer sheath comprises the following components in parts by weight: 60-80 parts of polyvinyl chloride, 20-30 parts of acrylic acid long carbon chain ester grafted nitrile rubber, 10-20 parts of polyether TPU, 3-5 parts of isooctyl stearate, 1-2 parts of diethylene glycol monobutyl adipate, 0.5-1 parts of a calcium zinc composite stabilizer, 2-4 parts of microcrystalline wax, 3-5 parts of hexafluorobutyl methacrylate, 20-30 parts of a filler and 4-8 parts of an auxiliary agent. The composite design standard of the photovoltaic branch cable of the invention can meet the working requirements of a photovoltaic system under outdoor low-temperature harsh environmental conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and in particular to a low-temperature resistant photovoltaic branch cable and a preparation method thereof. Background Art

[0002] With the development and utilization of new energy, photovoltaic power generation is becoming more and more popular as a green, clean and renewable energy. In the process of large-scale construction of photovoltaic power stations, the safe operation and service life design of photovoltaic power stations are particularly important. Photovoltaic cables, which are the power transmission medium of photovoltaic power generation systems, are of great significance to the safe and stable operation of photovoltaic power stations.

[0003] refer to Figure 1 The branch cable can be highly customized. The branch position can be set according to the needs of the power system distribution point. The branch line size and length can be determined according to the design requirements, which effectively shortens the construction period of the photovoltaic cable line, reduces material costs and construction costs, and ensures the reliability of power transmission. At present, the insulation and sheath materials used in photovoltaic branch cables are mostly low-smoke halogen-free flame-retardant cross-linked polyolefins or polyvinyl chloride. In high-cold areas, the insulation and sheath of branch cables are often damaged by low temperatures during laying and operation, resulting in a decrease in flexibility and mechanical strength or even cracking, which poses certain safety hazards. Summary of the invention

[0004] Purpose of the invention: In view of the above technical problems, the present invention proposes a low-temperature resistant photovoltaic branch cable and a preparation method thereof.

[0005] The technical solutions adopted are as follows:

[0006] A low-temperature resistant photovoltaic branch cable comprises an outer sheath, a thermal insulation layer, a wrapping layer, and a cable core, wherein the cable core comprises an inner sheath, a shielding layer, an insulating layer, and a conductor;

[0007] The outer sheath comprises the following components in parts by weight:

[0008] 60-80 parts of polyvinyl chloride, 20-30 parts of acrylic long-chain ester grafted nitrile rubber, 10-20 parts of polyether TPU, 3-5 parts of isooctyl stearate, 1-2 parts of diethylene glycol monobutyl adipate, 0.5-1 parts of calcium zinc composite stabilizer, 2-4 parts of microcrystalline paraffin, 3-5 parts of hexafluorobutyl methacrylate, 20-30 parts of filler, and 4-8 parts of additives.

[0009] Furthermore, the outer sheath comprises the following components in parts by weight:

[0010] 80 parts of polyvinyl chloride, 25 parts of acrylic long-chain ester grafted nitrile rubber, 20 parts of polyether TPU, 4 parts of isooctyl stearate, 2 parts of diethylene glycol monobutyl adipate, 1 part of calcium zinc composite stabilizer, 3 parts of microcrystalline paraffin, 3 parts of hexafluorobutyl methacrylate, 28 parts of filler, and 6 parts of additives.

[0011] Furthermore, the preparation method of the acrylic acid long carbon chain ester grafted nitrile rubber is as follows:

[0012] Add nitrile rubber to toluene, heat to 50-60°C, stir for 1-3h, then add long-chain acrylic acid ester and dibenzoyl peroxide, heat to 75-85°C, react for 4-8h, then return to room temperature, add methanol for precipitation and separation, vacuum dry the obtained solid to constant weight, then put it into Soxhlet extractor, use methanol as solvent, extract for 18-24h, and vacuum dry the extracted product to constant weight.

[0013] Furthermore, the long carbon chain acrylic acid ester is any one or more of dodecyl acrylate, tridecyl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexadecyl acrylate, heptadecanyl acrylate, and octadecyl acrylate.

[0014] Further, the filler includes carbon black, zinc oxide and aluminum hydroxide;

[0015] The mass ratio of the carbon black, zinc oxide and aluminum hydroxide is 2:1:1.

[0016] Furthermore, the auxiliary agent includes a flame retardant and a cross-linking agent;

[0017] The mass ratio of the flame retardant to the cross-linking agent is 2:1;

[0018] The flame retardant is antimony trioxide and tris(2-chloropropyl) phosphate;

[0019] The crosslinking agent is 2-di-n-butylamino-4,6-dimercapto-s-triazine.

[0020] Furthermore, the preparation method of the thermal insulation layer is as follows:

[0021] Add 4,4'-diaminodiphenyl ether and pyromellitic acid dianhydride to N-methylpyrrolidone, stir and react to obtain a precursor, then add 1,3,5-tri(aminophenoxy)benzene to react for 10-30 minutes, then add silica aerogel microspheres, acetic anhydride and pyridine, stir and mix evenly, pour the reaction solution onto a glass substrate, vacuum dry to remove the solvent and then cut.

[0022] Furthermore, the wrapping layer is any one or more of a polyimide film, a polytetrafluoroethylene film, a polyester film, and a mica tape.

[0023] The present invention provides a method for preparing a low-temperature resistant photovoltaic branch cable:

[0024] Select a conductor, use a concentric wrapping machine to wrap an insulating layer around the outside of the conductor, use a high-speed braiding machine to weave silver-plated or nickel-plated round copper wire to form a shielding layer with a braiding density of more than 85%, and then wrap the inner sheath around the outside of the shielding layer to obtain a cable core, wrap the cable core with the wrapping layer to fix it, and then use a concentric wrapping machine to wrap the insulation layer and the outer sheath in sequence around the wrapping layer.

[0025] Beneficial effects of the present invention:

[0026] The invention provides a low-temperature resistant photovoltaic branch cable. The outer sheath is a component that plays a protective role in the outermost layer of the photovoltaic branch cable. The nitrile rubber contains cyano and unsaturated double bonds, which can improve the low-temperature resistance of the outer sheath. After being grafted with acrylic acid long carbon chain ester, the introduction of flexible long chains improves the flexibility of the outer sheath, reduces rigidity, and further improves the low-temperature resistance of the outer sheath. In addition, it also has a certain solubilization effect during physical blending, plays the role of reducing interfacial energy, promoting phase dispersion, and strengthening interphase adhesion. The main chain structure of the polyether type TPU contains ether bonds. Because the ether bonds in the structure have low cohesive energy and are easy to rotate, the low-temperature flexibility of the outer sheath can be improved after being added, and the ether bonds are dispersed in the matrix continuous phase. It forms a macroscopic homogeneous phase and a microscopic phase separation (island phase structure) and acts as a stress concentrator, inducing a large number of shear bands and silver streaks, thereby greatly improving the impact strength of the outer sheath. The thermal insulation layer is a polyimide gel material. Due to its extremely small pore structure, it has the characteristics of low density and low thermal conductivity, which can protect the internal cable core and avoid damage to the conductor due to low temperature. The outer sheath material prepared by the present invention has excellent mechanical properties and flame retardant properties, and still has high impact strength at low temperatures, and can protect the normal operation of photovoltaic branch cables in low-temperature and high-cold areas. After testing, the composite design standard of photovoltaic branch cables can meet the working requirements of photovoltaic systems under harsh outdoor low-temperature conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a structural diagram of the connection between the branch cable and the main cable in the prior art;

[0028] Figure 2 This is a schematic diagram of the structure of a photovoltaic branch cable in Embodiment 1 of the present invention;

[0029] In the figure:

[0030] 1-outer sheath, 2-insulation layer, 3-wrapping layer, 4-inner sheath, 5-shielding layer, 6-insulating layer, 7-conductor. DETAILED DESCRIPTION

[0031] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0032] Polyvinyl chloride, Qufu Feida Plastic Products Co., Ltd., H-70;

[0033] Acrylic acid long carbon chain ester grafted nitrile rubber, homemade;

[0034] Polyether TPU, BASF, Germany, 1180A;

[0035] Isooctyl stearate, Nanjing Xinhuayuan Chemical Co., Ltd.; Diethylene glycol monobutyl adipate, Nanjing Xinhuayuan Chemical Co., Ltd.;

[0036] Calcium zinc composite stabilizer, Dongguan Lihuang Rubber and Plastic Materials Co., Ltd.;

[0037] Microcrystalline wax, Dongguan Lihuang Rubber & Plastic Material Co., Ltd.;

[0038] Hexafluorobutyl methacrylate, Harbin Xuejia Fluorosilicone Chemical Co., Ltd.;

[0039] Carbon black, Dongguan Lihuang Rubber & Plastic Material Co., Ltd., N330;

[0040] Zinc oxide, Dongguan Lihuang Rubber and Plastic Materials Co., Ltd.;

[0041] Aluminum hydroxide, Dongguan Lihuang Rubber and Plastic Materials Co., Ltd.;

[0042] Antimony trioxide, Hunan Chengxing Antimony Industry Co., Ltd.;

[0043] Tris(2-chloropropyl) phosphate, Shandong Xuguang Chemical Co., Ltd.;

[0044] 2-Di-n-butylamino-4,6-dimercapto-s-triazine, Shandong Xuguang Chemical Co., Ltd.;

[0045] Embodiment 1:

[0046] refer to Figure 2 , a low-temperature resistant photovoltaic branch cable, comprising an outer sheath (1), an insulation layer (2), a wrapping layer (3), and a cable core, wherein the cable core comprises an inner sheath (4), a shielding layer (5), an insulating layer (6), and a conductor (7);

[0047] The outer sheath (1) comprises the following components in parts by weight:

[0048] 80 parts of polyvinyl chloride, 25 parts of acrylic acid long-chain ester grafted nitrile rubber, 20 parts of polyether TPU, 4 parts of isooctyl stearate, 2 parts of diethylene glycol monobutyl adipate, 1 part of calcium zinc composite stabilizer, 3 parts of microcrystalline wax, 3 parts of hexafluorobutyl methacrylate, 14 parts of carbon black, 7 parts of zinc oxide, 7 parts of aluminum hydroxide, 2 parts of antimony trioxide, 2 parts of tris(2-chloropropyl) phosphate, and 2 parts of 2-di-n-butylamino-4,6-dimercapto-s-triazine.

[0049] Wherein, the preparation method of acrylic acid long carbon chain ester grafted nitrile rubber is as follows:

[0050] Add 500g of nitrile rubber to 5L of toluene, heat to 60℃ and stir for 2h, then add 50g of dodecyl acrylate and 1g of dibenzoyl peroxide, heat to 80℃ and react for 5h, then return to room temperature, add methanol for precipitation and separation, the obtained solid is vacuum dried to constant weight and placed in a Soxhlet extractor with methanol as solvent, extract for 24h, and the extracted product is vacuum dried to constant weight.

[0051] The preparation method of the thermal insulation layer (2) is as follows:

[0052] Add 479.6 g of 4,4'-diaminodiphenyl ether and 519.5 g of pyromellitic anhydride to 6 L of N-methylpyrrolidone, stir and react for 5 h to obtain a precursor, then add 25 g of 1,3,5-tris(aminophenoxy)benzene and react for 20 min, then add 120 g of silica aerogel microspheres, 80.2 g of acetic anhydride and 64 g of pyridine, stir and mix well, pour the reaction solution onto a glass substrate, vacuum dry to remove the solvent and then cut.

[0053] The wrapping layer (3) is a mica tape;

[0054] The inner sheath (4) is cross-linked polyethylene XLPE XL140;

[0055] The shielding layer (5) is a nickel-plated braided copper mesh;

[0056] The insulating layer (6) is cross-linked polyethylene XLPE XL140;

[0057] Preparation method of the above low temperature resistant photovoltaic branch cable:

[0058] A nickel-plated copper stranded wire with a specification of AWG10 is selected as a conductor (7), an insulating layer (6) is wrapped around the outer side of the conductor (7) by a concentric wrapping machine, and then a high-speed braiding machine is used to braid the nickel-plated round copper wire to form a shielding layer (5), with a braiding density of more than 85%, and then an inner sheath (4) is wrapped around the outer side of the shielding layer (5) to obtain a cable core, the cable core is wrapped and fixed with a wrapping layer (3), and then a concentric wrapping machine is used to wrap an insulation layer (2) and an outer sheath (1) in sequence around the outer side of the wrapping layer (3).

[0059] Embodiment 2:

[0060] A low-temperature resistant photovoltaic branch cable comprises an outer sheath (1), a thermal insulation layer (2), a wrapping layer (3), and a cable core, wherein the cable core comprises an inner sheath (4), a shielding layer (5), an insulating layer (6), and a conductor (7);

[0061] The outer sheath (1) comprises the following components in parts by weight:

[0062] 80 parts of polyvinyl chloride, 30 parts of acrylic acid long-chain ester grafted nitrile rubber, 20 parts of polyether TPU, 5 parts of isooctyl stearate, 2 parts of diethylene glycol monobutyl adipate, 1 part of calcium zinc composite stabilizer, 4 parts of microcrystalline wax, 5 parts of hexafluorobutyl methacrylate, 14 parts of carbon black, 7 parts of zinc oxide, 7 parts of aluminum hydroxide, 2 parts of antimony trioxide, 2 parts of tris(2-chloropropyl) phosphate, and 2 parts of 2-di-n-butylamino-4,6-dimercapto-s-triazine.

[0063] Wherein, the preparation method of acrylic acid long carbon chain ester grafted nitrile rubber is as follows:

[0064] Add 500g of nitrile rubber to 5L of toluene, heat to 60℃ and stir for 3h, then add 50g of dodecyl acrylate and 1g of dibenzoyl peroxide, heat to 85℃ and react for 8h, then return to room temperature, add methanol for precipitation and separation, the obtained solid is vacuum dried to constant weight and placed in a Soxhlet extractor with methanol as solvent, extract for 24h, and the extracted product is vacuum dried to constant weight.

[0065] The preparation method of the insulation layer is as follows:

[0066] Add 479.6 g of 4,4'-diaminodiphenyl ether and 519.5 g of pyromellitic anhydride to 6 L of N-methylpyrrolidone, stir and react for 5 h to obtain a precursor, then add 25 g of 1,3,5-tri(aminophenoxy)benzene and react for 30 min, then add 120 g of silica aerogel microspheres, 80.2 g of acetic anhydride and 64 g of pyridine, stir and mix well, pour the reaction solution onto a glass substrate, vacuum dry to remove the solvent and then cut.

[0067] The wrapping layer (3) is a mica tape;

[0068] The inner sheath (4) is cross-linked polyethylene XLPE XL140;

[0069] The shielding layer (5) is a nickel-plated braided copper mesh;

[0070] The insulating layer (6) is cross-linked polyethylene XLPE XL140;

[0071] Preparation method of the above low temperature resistant photovoltaic branch cable:

[0072] A nickel-plated copper stranded wire with a specification of AWG10 is selected as a conductor (7), an insulating layer (6) is wrapped around the outer side of the conductor (7) by a concentric wrapping machine, and then a high-speed braiding machine is used to braid the nickel-plated round copper wire to form a shielding layer (5), with a braiding density of more than 85%, and then an inner sheath (4) is wrapped around the outer side of the shielding layer (5) to obtain a cable core, the cable core is wrapped and fixed with a wrapping layer (3), and then a concentric wrapping machine is used to wrap an insulation layer (2) and an outer sheath (1) in sequence around the outer side of the wrapping layer (3).

[0073] Embodiment 3:

[0074] A low-temperature resistant photovoltaic branch cable comprises an outer sheath (1), a thermal insulation layer (2), a wrapping layer (3), and a cable core, wherein the cable core comprises an inner sheath (4), a shielding layer (5), an insulating layer (6), and a conductor (7);

[0075] The outer sheath (1) comprises the following components in parts by weight:

[0076] 60 parts of polyvinyl chloride, 20 parts of acrylic acid long carbon chain ester grafted nitrile rubber, 10 parts of polyether TPU, 3 parts of isooctyl stearate, 1 part of diethylene glycol monobutyl adipate, 0.5 parts of calcium zinc composite stabilizer, 2 parts of microcrystalline wax, 3 parts of hexafluorobutyl methacrylate, 14 parts of carbon black, 7 parts of zinc oxide, 7 parts of aluminum hydroxide, 2 parts of antimony trioxide, 2 parts of tris(2-chloropropyl) phosphate, and 2 parts of 2-di-n-butylamino-4,6-dimercapto-s-triazine.

[0077] Wherein, the preparation method of acrylic acid long carbon chain ester grafted nitrile rubber is as follows:

[0078] Add 500g of nitrile rubber to 5L of toluene, heat to 50℃ and stir for 1h, then add 50g of dodecyl acrylate and 1g of dibenzoyl peroxide, heat to 75℃ and react for 4h, then return to room temperature, add methanol for precipitation and separation, the obtained solid is vacuum dried to constant weight and placed in a Soxhlet extractor with methanol as solvent, extract for 18h, and the extracted product is vacuum dried to constant weight.

[0079] The preparation method of the insulation layer is as follows:

[0080] Add 479.6 g of 4,4'-diaminodiphenyl ether and 519.5 g of pyromellitic anhydride to 6 L of N-methylpyrrolidone, stir and react for 3 h to obtain a precursor, then add 25 g of 1,3,5-tri(aminophenoxy)benzene and react for 10 min, then add 120 g of silica aerogel microspheres, 80.2 g of acetic anhydride and 64 g of pyridine, stir and mix well, pour the reaction solution onto a glass substrate, vacuum dry to remove the solvent and then cut.

[0081] The wrapping layer (3) is a mica tape;

[0082] The inner sheath (4) is cross-linked polyethylene XLPE XL140;

[0083] The shielding layer (5) is a nickel-plated braided copper mesh;

[0084] The insulating layer (6) is cross-linked polyethylene XLPE XL140;

[0085] Preparation method of the above low temperature resistant photovoltaic branch cable:

[0086] A nickel-plated copper stranded wire with a specification of AWG10 is selected as a conductor (7), an insulating layer (6) is wrapped around the outer side of the conductor (7) by a concentric wrapping machine, and then a high-speed braiding machine is used to braid the nickel-plated round copper wire to form a shielding layer (5), with a braiding density of more than 85%, and then an inner sheath (4) is wrapped around the outer side of the shielding layer (5) to obtain a cable core, the cable core is wrapped and fixed with a wrapping layer (3), and then a concentric wrapping machine is used to wrap an insulation layer (2) and an outer sheath (1) in sequence around the outer side of the wrapping layer (3).

[0087] Embodiment 4:

[0088] The invention is substantially the same as the embodiment 1, except that, in parts by weight, the outer sheath (1) comprises the following components:

[0089] 80 parts of polyvinyl chloride, 20 parts of acrylic acid long carbon chain ester grafted nitrile rubber, 20 parts of polyether TPU, 3 parts of isooctyl stearate, 2 parts of diethylene glycol monobutyl adipate, 0.5 parts of calcium zinc composite stabilizer, 4 parts of microcrystalline wax, 3 parts of hexafluorobutyl methacrylate, 14 parts of carbon black, 7 parts of zinc oxide, 7 parts of aluminum hydroxide, 2 parts of antimony trioxide, 2 parts of tris(2-chloropropyl) phosphate, and 2 parts of 2-di-n-butylamino-4,6-dimercapto-s-triazine.

[0090] Embodiment 5:

[0091] The invention is substantially the same as the embodiment 1, except that, in parts by weight, the outer sheath (1) comprises the following components:

[0092] 60 parts of polyvinyl chloride, 30 parts of acrylic acid long-chain ester grafted nitrile rubber, 10 parts of polyether TPU, 5 parts of isooctyl stearate, 1 part of diethylene glycol monobutyl adipate, 1 part of calcium zinc composite stabilizer, 2 parts of microcrystalline wax, 5 parts of hexafluorobutyl methacrylate, 14 parts of carbon black, 7 parts of zinc oxide, 7 parts of aluminum hydroxide, 2 parts of antimony trioxide, 2 parts of tris(2-chloropropyl) phosphate, and 2 parts of 2-di-n-butylamino-4,6-dimercapto-s-triazine.

[0093] Comparative Example 1:

[0094] The method is basically the same as Example 1, except that no acrylic acid long-chain ester grafted nitrile rubber is added to the outer sheath (1).

[0095] Comparative Example 2:

[0096] The method is basically the same as Example 1, except that nitrile rubber is directly added to replace the nitrile rubber grafted with long carbon chain acrylic acid ester in the outer sheath (1).

[0097] Comparative Example 3:

[0098] It is basically the same as Example 1, except that no polyether TPU is added to the outer sheath (1).

[0099] Comparative Example 4:

[0100] The method is basically the same as Example 1, except that hexafluorobutyl methacrylate is not added to the outer sheath (1).

[0101] Comparative Example 5:

[0102] The method is basically the same as Example 1, except that 2-di-n-butylamino-4,6-dimercapto-s-triazine is not added to the outer sheath (1).

[0103] Performance Test:

[0104] ① The outer sheath (1) materials prepared in Examples 1-5 of the present invention and Comparative Examples 1-5 were used as samples for performance testing;

[0105] Tensile performance test: According to GB / T1004-2006 standard, the tensile strength and elongation at break were tested using an electronic material universal testing machine at a tensile rate of 50 mm / min.

[0106] Low temperature impact test: According to GB / T2843-2008 standard, the low temperature impact strength of the sample is tested using a simply supported beam impact testing machine at a temperature of -50±2℃.

[0107] Limiting oxygen index test: According to ASTMD 2863 standard, the limiting oxygen index refers to the minimum oxygen concentration volume fraction required for the sample to maintain balanced combustion in a mixed gas of oxygen and nitrogen, expressed as the percentage of oxygen in the mixed gas.

[0108] The test results are shown in Table 1 below:

[0109] Table 1:

[0110]

[0111] As can be seen from Table 1 above, the outer sheath (1) material prepared in the present invention has excellent mechanical properties and flame retardant properties, and still has high impact strength at low temperatures, and can protect the normal operation of photovoltaic branch cables in low-temperature and cold areas.

[0112] ② The photovoltaic branch cables prepared in Examples 1-5 and Comparative Examples 1-5 of the present invention were used as samples for performance testing;

[0113] Volume resistivity test: Take a 5m sample and place it in (90±2℃)℃ water for 2h, then add a DC voltage of 80~500V between the conductor and the water, and measure the insulation resistance after 1min. The test requires that the insulation volume resistivity at 90℃ is ≥10 11 Ω·cm;

[0114] Low temperature impact test: According to clause 8.5 of GB / T2951.14-2008, cooling temperature is -50±2℃, time is 16h, weight of falling hammer is 1kg, weight of impact block is 200g, drop height is 100mm, and the test requires that there should be no visible cracks on the surface;

[0115] Low temperature bending test: According to clause 8.2 of GB / T2951.14-2008, the cooling temperature is -50±2℃, the time is 16h, the diameter of the test rod is 4-5 times the outer diameter of the cable, and it is wound 3-4 times. The test requires that there should be no visible cracks on the surface.

[0116] DC voltage resistance test: Take a 5m sample and put it into distilled water with a temperature of (85±2℃)℃ and 3% NaCl for (240±2)h. Then add a DC voltage of 0.9kV to the conductor and water. The leakage current change in 24h is not more than 10%, and it is subjected to an AC voltage of 1.0kV in room temperature water. The test requires that the leakage current change in 24h is not more than 10%, and the sample has no breakdown.

[0117] The test results are shown in Table 2 below:

[0118] Table 2:

[0119]

[0120] It can be seen from Table 2 above that the composite design standard of the photovoltaic branch cable prepared by the present invention can meet the working requirements of the photovoltaic system under outdoor low temperature and harsh environmental conditions.

[0121] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low temperature resistant photovoltaic branch cable, characterized in that: It includes an outer sheath, a thermal insulation layer, a wrapping layer, and a cable core, wherein the cable core includes an inner sheath, a shielding layer, an insulating layer, and a conductor; The outer sheath comprises the following components in parts by weight: 60-80 parts of polyvinyl chloride, 20-30 parts of acrylic acid long carbon chain ester grafted nitrile rubber, 10-20 parts of polyether TPU, 3-5 parts of isooctyl stearate, 1-2 parts of diethylene glycol monobutyl adipate, 0.5-1 parts of calcium zinc composite stabilizer, 2-4 parts of microcrystalline paraffin, 3-5 parts of hexafluorobutyl methacrylate, 20-30 parts of filler, 4-8 parts of additives; The auxiliary agent includes a flame retardant and a cross-linking agent; The mass ratio of the flame retardant to the cross-linking agent is 2:1; The flame retardant is antimony trioxide and tris(2-chloropropyl) phosphate; The cross-linking agent is 2-di-n-butylamino-4,6-dimercapto-s-triazine; The preparation method of the acrylic acid long carbon chain ester grafted nitrile rubber is as follows: Add nitrile rubber to toluene, heat to 50-60°C and stir for 1-3h, then add long-chain acrylic acid ester and dibenzoyl peroxide, heat to 75-85°C and react for 4-8h, then return to room temperature, add methanol for precipitation and separation, vacuum dry the obtained solid to constant weight and put it into Soxhlet extractor, use methanol as solvent, extract for 18-24h, and vacuum dry the extracted product to constant weight; The long carbon chain acrylic acid ester is any one or more of dodecyl acrylate, tridecyl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexadecyl acrylate, heptadecanyl acrylate, and octadecyl acrylate.

2. The low temperature resistant photovoltaic branch cable according to claim 1, characterized in that: The outer sheath comprises the following components in parts by weight: 80 parts of polyvinyl chloride, 25 parts of acrylic long-chain ester grafted nitrile rubber, 20 parts of polyether TPU, 4 parts of isooctyl stearate, 2 parts of diethylene glycol monobutyl adipate, 1 part of calcium zinc composite stabilizer, 3 parts of microcrystalline paraffin, 3 parts of hexafluorobutyl methacrylate, 28 parts of filler, and 6 parts of additives.

3. The low temperature resistant photovoltaic branch cable according to claim 1, characterized in that: The filler includes carbon black, zinc oxide and aluminum hydroxide; The mass ratio of the carbon black, zinc oxide and aluminum hydroxide is 2:1:

1.

4. The low temperature resistant photovoltaic branch cable according to claim 1, characterized in that: The preparation method of the thermal insulation layer is as follows: Add 4,4'-diaminodiphenyl ether and pyromellitic acid dianhydride to N-methylpyrrolidone, stir and react to obtain a precursor, then add 1,3,5-tri(aminophenoxy)benzene to react for 10-30 minutes, then add silica aerogel microspheres, acetic anhydride and pyridine, stir and mix evenly, pour the reaction solution onto a glass substrate, vacuum dry to remove the solvent and then cut.

5. The low temperature resistant photovoltaic branch cable according to claim 1, characterized in that: The wrapping layer is any one or more of a polyimide film, a polytetrafluoroethylene film, a polyester film, and a mica tape.

6. A method for preparing a low temperature resistant photovoltaic branch cable according to any one of claims 1 to 5, characterized in that: Select a conductor, use a concentric wrapping machine to wrap an insulating layer around the outside of the conductor, use a high-speed braiding machine to weave silver-plated or nickel-plated round copper wire to form a shielding layer with a braiding density of more than 85%, and then wrap the inner sheath around the outside of the shielding layer to obtain a cable core, wrap the cable core with the wrapping layer to fix it, and then use a concentric wrapping machine to wrap the insulation layer and the outer sheath in sequence around the wrapping layer.

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