Expansion wire for photovoltaic system and manufacturing method thereof

Abstract

The invention discloses a capacity expansion lead for a photovoltaic system, which comprises a carbon fiber core group and a soft aluminum conductor coated on the outer side of the carbon fiber core group, the carbon fiber core group is formed by stranding a plurality of strands of carbon fiber composite cores, and each strand of carbon fiber composite core is impregnated and coated by a coating. The invention further provides a manufacturing method of the capacity expansion wire for the photovoltaic system, and the problem that an existing steel core soft aluminum stranded wire cannot adapt to a renewable energy source centralized power generation and long-distance efficient transmission high-demand scene is solved. Compared with a traditional steel-cored aluminum stranded wire, the carbon fiber composite core wire has the advantages of being light in weight, high in strength, low in line loss, resistant to high temperature, environment-friendly and the like. By increasing the sectional area and adopting a high-conductivity material (such as carbon fiber), the direct-current resistance is fundamentally reduced, the loss and the voltage drop are reduced, and the efficiency and the stability of the system are improved.

Description

Technical Field

[0001] This invention relates to the field of conductor manufacturing technology, and specifically to a capacity-enhancing conductor for photovoltaic systems and its manufacturing method. Background Technology

[0002] In recent years, the global pursuit of renewable energy has been increasing, and photovoltaic (PV) power generation, as a leading example, has demonstrated significant advantages over traditional coal-fired power generation due to its clean and environmentally friendly characteristics. However, large-scale distributed PV grid connection poses challenges to existing power distribution networks. Traditional transmission lines mainly use steel-cored aluminum stranded wire, which operates at temperatures of 80°C and below, limiting its power transmission capacity. Therefore, without altering the existing transmission layout, utilizing high-temperature, low-sag conductors to increase thermal rating and improve transmission capacity can provide an upgrade technology for transmission lines. High-temperature, low-sag conductors can maintain low sag and good mechanical properties under high-temperature conditions, thereby increasing the transmission capacity of transmission lines, improving the reliability and security of the power grid, and supporting PV power generation.

[0003] Existing high-temperature, low-sag conductors mainly include trapezoidal or steel-cored soft aluminum stranded wire, intermittent steel-cored heat-resistant aluminum alloy stranded wire, and Invar steel-cored ultra-heat-resistant aluminum alloy stranded wire. However, their operating temperature is generally around 120℃, and their transmission capacity can only be increased by 50-80% compared to ordinary steel-cored aluminum stranded wire. To adapt to scenarios with higher demands, such as centralized renewable energy power generation and long-distance high-efficiency transmission, this invention proposes a capacity-enhancing conductor for photovoltaic systems and its manufacturing method. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the existing steel-cored soft aluminum stranded wire cannot meet the high demand scenarios of centralized power generation and long-distance high-efficiency transmission of renewable energy. The purpose is to provide a capacity expansion conductor for photovoltaic systems and its manufacturing method.

[0005] In a first aspect, the present invention is achieved through the following technical solution: A capacity-enhancing conductor for a photovoltaic system includes a carbon fiber core assembly and a soft aluminum conductor covering the outside of the carbon fiber core assembly. The carbon fiber core assembly is formed by stranding multiple carbon fiber composite cores, and each carbon fiber composite core is coated with a coating.

[0006] In one specific embodiment, the carbon fiber composite core comprises the following raw materials by weight: 80-120 parts acrylonitrile, 2-3 parts epoxy resin, 40-60 parts carbon fiber, 1-2 parts first curing agent, and 2-3 parts diluent. In one specific embodiment, the inner diameter of the soft aluminum conductor is larger than the outer diameter of the carbon fiber composite core.

[0007] Secondly, the present invention also provides a method for manufacturing a capacity-enhancing conductor for a photovoltaic system, comprising the following steps: To prepare a carbon fiber composite core, the prepared multi-strand carbon fiber composite core is twisted together to obtain a carbon fiber core assembly. Tension is applied to the carbon fiber core assembly, and a soft aluminum conductor is stranded in a frame around the outside of the stretched carbon fiber core assembly. The soft aluminum conductor is coaxially arranged with the carbon fiber core assembly, and the capacity expansion wire for photovoltaic system is finally obtained.

[0008] In one specific embodiment, the step of preparing the carbon fiber composite core is as follows: Preparation of resin mixture system: Weigh acrylonitrile and dimethyl sulfoxide solvent, mix them, heat to 60-70℃, stir for 30-40 min, then add epoxy resin and stir for 30-40 min while maintaining at 60-70℃ to obtain the first mixture system; Carbon fiber pretreatment: Weigh the carbon fiber, add it to dimethylacetamide solvent, heat to 50°C, stir under ultrasonic conditions for 30-35 minutes, and then mix it with the first mixing system to obtain the second mixing system; Composite curing: Add the first curing agent and diluent to the obtained second mixture system, stir evenly, and let stand at room temperature for 3-5 hours to obtain product A; Oxidation and carbonization treatment: First, the obtained product A is placed in an oxidation furnace for pre-oxidation at 200-300℃ for 1-2 hours. Then, product A is carbonized at a low temperature of 400℃-800℃, and then carbonized at a high temperature of 1000℃-2000℃. Finally, the carbon fiber composite core is formed by sequential qualitative and drawing processes. The carbon fiber composite core is then dried and pretreated before being inserted into an impregnation tank under the tension of a traction machine. The coating is made of resin material, which completely covers and reinforces the carbon fiber composite core.

[0009] In one specific embodiment, the resulting carbon fiber composite core has a tensile strength ≥3500 MPa, a tensile modulus of elasticity of 260-430 GPa, and a longitudinal coefficient of thermal expansion ≤1.0 × 10⁻⁶. -6 / ℃, transverse thermal expansion coefficient ≤1.8×10 -6 / ℃.

[0010] In one specific embodiment, the resin material comprises the following raw materials by weight: 100 parts of thermosetting resin, 50-150 parts of curing agent, 1-20 parts of accelerator and 1-20 parts of release agent.

[0011] In one specific embodiment, the thermosetting resin includes one or more of epoxy resin, polyester resin, and vinyl ester.

[0012] In one specific embodiment, the obtained capacity-enhancing wire has a conductivity ≥62% IACS, a tensile strength of 80-85MPa, and an elongation of 30-35%.

[0013] In one specific embodiment, when the carbon fiber composite core is pre-tensioned, the pre-tension is 40-50% of the total tensile strength of the carbon fiber composite core, and the pre-tensioning time is 0.5-1 min.

[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. Compared with traditional steel-cored aluminum stranded wire, carbon fiber composite core conductors have advantages such as light weight, high strength, low line loss, high temperature resistance, and environmental friendliness. By increasing the cross-sectional area and using high conductivity materials (such as carbon fiber), DC resistance is fundamentally reduced, losses and voltage drop are reduced, and system efficiency and stability are improved.

[0015] Compared to steel-cored aluminum stranded wire of the same diameter, the conductor's conductive cross-section increases by 5%-10%, and the operating temperature rises from 70 degrees Celsius to over 180 degrees Celsius. Transmission capacity is increased by 120%-150%. This expansion conductor can achieve a line capacity increase of over 120%, making it particularly suitable for photovoltaic system circuit upgrades utilizing existing towers and transmission channels, and for scenarios where power transmission capacity is limited. Attached Figure Description To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 A flowchart illustrating the manufacturing process of expansion conductors for photovoltaic systems; Detailed Implementation In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0016] Example 1 This embodiment discloses a capacity-enhancing conductor for a photovoltaic system, comprising a carbon fiber core assembly and a soft aluminum conductor covering the outside of the carbon fiber core assembly. The carbon fiber core assembly comprises a multi-stranded carbon fiber composite core, each strand of which is impregnated with a coating. In this embodiment, the coating is a resin material, applied after qualitative and drawing treatments.

[0017] In this embodiment, there are 6 soft aluminum conductors, all of which are heat-resistant aluminum alloy wires with a diameter of 3.0 mm.

[0018] like Figure 1 As shown, the manufacturing method of the expansion conductor for the above photovoltaic system is as follows: (1) First, prepare the carbon fiber composite core, including the following steps: Preparation of resin mixture system: Weigh 2 kg of acrylonitrile (PAN) and mix with 350 ml of dimethyl sulfoxide (DMSO) solvent, heat to 65 °C, stir for 30 min, then add 50 g of epoxy resin and stir for 30 min while maintaining the temperature at 65 °C to obtain the first mixture system.

[0019] Carbon fiber pretreatment: Weigh 1 kg of carbon fiber and add it to 350 ml of dimethylacetamide (DMAc) solvent. Heat to 50 °C and stir under ultrasonic conditions for 35 min. Then mix with the first mixing system to obtain the second mixing system.

[0020] Composite curing: 35g of the first curing agent and 50g of diluent were added to the obtained second mixture, stirred evenly, and allowed to stand at room temperature for 3 hours to obtain product A. The first curing agent is polyamide, which in this embodiment is synthesized from dimer acids and polyamines, including but not limited to linoleic acid dimer and ethylenediamine. The diluent is an acrylate, including but not limited to diacrylates.

[0021] Oxidation and carbonization treatment: The obtained product A is first placed in an oxidation furnace for pre-oxidation at 280°C for 2 hours.

[0022] The resulting product A was then carbonized at a low temperature of 600°C, followed by high-temperature carbonization at 1800°C.

[0023] Finally, the carbon fiber composite core is formed through qualitative and drawing processes. After drying pretreatment, the carbon fiber composite core is then immersed in an impregnation tank under the tension of a traction machine to fully saturate it with the resin coating. The coating is a resin material that completely encapsulates the reinforced carbon fiber composite core. The resin material comprises the following raw materials by weight: 100 parts thermosetting resin, 100 parts second curing agent, 10 parts accelerator, and 10 parts release agent. Specifically, the second curing agent has the same composition as the first curing agent, both being polyamide. In this embodiment, the polyamide is synthesized from dimer acid and polyamines, including but not limited to linoleic acid dimer and ethylenediamine. The accelerator contains rare earth elements (such as scandium and yttrium) to refine the grain size and reduce the impact of impurities on conductivity. The release agent includes fluoroalkylsiloxanes, which have low surface energy and reduce resin adhesion.

[0024] Furthermore, thermosetting resins include epoxy resins, polyester resins, and one or more vinyl esters.

[0025] (2) The prepared multi-strand carbon fiber composite core is stranded to obtain a carbon fiber core assembly; (3) In this embodiment, the total tensile strength of the carbon fiber composite core is 1600-2000N; a constant tension of 800N for 50s is applied to the carbon fiber core group, and a soft aluminum conductor is stranded in a frame on the outside of the carbon fiber core group under applied tension. The soft aluminum conductor is coaxially arranged with the carbon fiber core group, and finally the expansion conductor for photovoltaic system is obtained.

[0026] Furthermore, the obtained carbon fiber composite core has a tensile strength of 4500 MPa, a tensile modulus of elasticity of 430 GPa, and a longitudinal coefficient of thermal expansion of 0.5 × 10⁻⁶. -6 / ℃, the transverse thermal expansion coefficient is 1.4×10 -6 / ℃. Furthermore, the obtained expanded conductor has a conductivity of 62.8% IACS, a tensile strength of 82 MPa, and an elongation of 35%.

[0027] Example 2 This embodiment discloses a capacity-enhancing conductor for a photovoltaic system, comprising a carbon fiber core assembly and a soft aluminum conductor covering the outside of the carbon fiber core assembly. The carbon fiber core assembly comprises a multi-stranded carbon fiber composite core, each strand of which is impregnated with a coating. In this embodiment, the coating is a resin material, applied after qualitative and drawing treatments. like Figure 1 As shown, the manufacturing method of the expansion conductor for the above photovoltaic system is as follows: (1) First, prepare the carbon fiber composite core, including the following steps: Preparation of resin mixture system: Weigh 1 kg of acrylonitrile (PAN) and mix with 380 ml of dimethyl sulfoxide (DMSO) solvent, heat to 60 °C, stir for 35 min, then add 27 g of epoxy resin and stir for 35 min while maintaining the temperature at 60 °C to obtain the first mixture system.

[0028] Carbon fiber pretreatment: Weigh 0.4 kg of carbon fiber and add it to 380 ml of dimethylacetamide (DMAc) solvent. Heat to 50 °C and stir under ultrasonic conditions for 32 min. Then mix with the first mixing system to obtain the second mixing system.

[0029] Composite curing: Add 20g of the first curing agent and 30g of diluent to the obtained second mixture, stir evenly, and let stand at room temperature for 3 hours. The first curing agent is polyamide, which in this embodiment is synthesized from dimer acids and polyamines, including but not limited to linoleic acid dimer and ethylenediamine. The diluent is an acrylate, including but not limited to diacrylates.

[0030] Oxidation and carbonization treatment: The obtained product is first placed in an oxidation furnace for pre-oxidation at 200°C for 1 hour.

[0031] The resulting product was then carbonized at a low temperature of 400°C, followed by high-temperature carbonization at 1000°C.

[0032] Finally, the carbon fiber composite core undergoes qualitative and drawing processes, followed by drying pretreatment. Then, under the tension of a traction machine, it enters an impregnation tank to fully saturate with the coating adhesive. The coating is a resin material, ensuring complete coverage of the reinforced carbon fiber composite core. The resin material comprises the following raw materials by weight: 100 parts thermosetting resin, 60 parts second curing agent, 3 parts accelerator, and 4 parts release agent. Specifically, the second curing agent has the same composition as the first curing agent, both being polyamide. In this embodiment, the polyamide is synthesized from dimer acid and polyamines, including but not limited to linoleic acid dimer and ethylenediamine. The accelerator contains rare earth elements (such as scandium and yttrium), thereby refining the grain size and reducing the impact of impurities on conductivity. The release agent includes fluoroalkylsiloxanes, which have low surface energy and reduce resin adhesion.

[0033] Furthermore, thermosetting resins include epoxy resins, polyester resins, and one or more vinyl esters.

[0034] (2) The prepared multi-strand carbon fiber composite core is stranded to obtain a carbon fiber core assembly; (3) In this embodiment, the total tensile strength of the carbon fiber composite core is 1600-2000N; a constant tension of 700N for 60s is applied to the carbon fiber core group, and a soft aluminum conductor is stranded in a frame on the outside of the carbon fiber core group under applied tension. The soft aluminum conductor is coaxially arranged with the carbon fiber core group, and finally the expansion conductor for photovoltaic system is obtained.

[0035] Furthermore, the obtained carbon fiber composite core has a tensile strength of 3800 MPa, a tensile modulus of elasticity of 340 GPa, and a longitudinal coefficient of thermal expansion of 1.0 × 10⁻⁶. -6 / ℃, the transverse thermal expansion coefficient is 1.8×10 -6 / ℃. Furthermore, the obtained expanded conductor has a conductivity of 62.3% IACS, a tensile strength of 76 MPa, and an elongation of 32%.

[0036] Example 3 This embodiment discloses a capacity-enhancing conductor for a photovoltaic system, comprising a carbon fiber core assembly and a soft aluminum conductor covering the outside of the carbon fiber core assembly. The carbon fiber core assembly comprises a multi-strand stranded carbon fiber composite core, each strand of which is impregnated with a coating. In this embodiment, the coating is a resin material. like Figure 1 As shown, the manufacturing method of the expansion conductor for the above photovoltaic system is as follows: (1) First, prepare the carbon fiber composite core, including the following steps: Preparation of resin mixture system: Weigh 2 kg of acrylonitrile (PAN) and mix with 400 ml of dimethyl sulfoxide (DMSO) solvent, heat to 70 °C, stir for 40 min, then add 50 g of epoxy resin and stir for 40 min while maintaining the temperature at 70 °C to obtain the first mixture system.

[0037] Carbon fiber pretreatment: Weigh 1.2 kg of carbon fiber and add it to 400 ml of dimethylacetamide (DMAc) solvent. Heat to 50 °C and stir under ultrasonic conditions for 30 min. Then mix with the first mixing system to obtain the second mixing system.

[0038] Composite curing: Add 30g of the first curing agent and 45g of diluent to the obtained second mixture, stir evenly, and let stand at room temperature for 5 hours. The first curing agent is polyamide, which in this embodiment is synthesized from dimer acids and polyamines, including but not limited to linoleic acid dimer and ethylenediamine. The diluent is an acrylate, including but not limited to diacrylates.

[0039] Oxidation and carbonization treatment: The obtained product is first placed in an oxidation furnace for pre-oxidation at 300°C for 1.8 hours.

[0040] The resulting product was then carbonized at a low temperature of 800℃, followed by high-temperature carbonization at 2000℃.

[0041] Finally, the carbon fiber composite core undergoes qualitative and drawing processes, followed by drying pretreatment. Then, under the tension of a traction machine, it enters an impregnation tank to fully saturate with the coating adhesive. The coating is a resin material, ensuring complete coverage of the reinforced carbon fiber composite core. The resin material comprises the following raw materials by weight: 80 parts thermosetting resin, 100 parts second curing agent, 15 parts accelerator, and 15 parts release agent. Specifically, the second curing agent has the same composition as the first curing agent, both being polyamide. In this embodiment, the polyamide is synthesized from dimer acid and polyamines, including but not limited to linoleic acid dimer and ethylenediamine. The accelerator contains rare earth elements (such as scandium and yttrium), thereby refining the grain size and reducing the impact of impurities on conductivity. The release agent includes fluoroalkylsiloxanes, which have low surface energy and reduce resin adhesion.

[0042] Furthermore, thermosetting resins include epoxy resins, polyester resins, and one or more vinyl esters.

[0043] (2) The prepared multi-strand carbon fiber composite core is stranded to obtain a carbon fiber core assembly; (3) In this embodiment, the total tensile strength of the carbon fiber composite core is 1600-2000N; a constant tension of 1000N for 30s is applied to the carbon fiber core group, and a soft aluminum conductor is stranded in a frame on the outside of the carbon fiber core group under applied tension. The soft aluminum conductor is coaxially arranged with the carbon fiber core group, and finally the expansion conductor for photovoltaic system is obtained.

[0044] Furthermore, the resulting carbon fiber composite core has a tensile strength of 3500 MPa, a tensile modulus of elasticity of 260 GPa, and a longitudinal coefficient of thermal expansion of 0.8 × 10⁻⁶. -6 / ℃, the transverse thermal expansion coefficient is 1.6×10 -6 / ℃. Furthermore, the obtained expanded conductor has a conductivity of 62.1% IACS, a tensile strength of 82 MPa, and an elongation of 30%.

[0045] Example 4: Performance Comparison Comparative Example 1 The existing manufacturing method for steel-cored aluminum stranded wire is as follows: First, the aluminum rods are oxidized and cleaned, then cut into appropriate lengths using a shearing machine. Next, the aluminum rods are placed in a heating furnace for preheating. The steel is heated and then drawn into the required diameter and length using a wire drawing machine; Aluminum rods and steel cores are placed into a stranding machine according to a specified stranding ratio for stranding. The stranding machine uses a high-speed rotating stranding shaft to strand the aluminum rods and steel cores together to form steel-cored aluminum stranded wire. The steel-cored aluminum stranded wire is then cleaned and deoxidized to ensure its smoothness and conductivity.

[0046] The expanded conductors prepared in Comparative Example 1 and Example 1 were compared, and the comparison results are shown in Table 1.

[0047] Table 1 Performance Comparison Results

[0048] Conclusion: Compared with steel-cored aluminum stranded wire of the same diameter, the conductor's conductive cross-section increases by 5%–10%, and the operating temperature increases from 70 degrees Celsius to over 180 degrees Celsius. Transmission capacity is increased by over 120%. This conductor is suitable for photovoltaic system circuit upgrades utilizing existing towers and transmission channels where power transmission capacity is limited, achieving a line capacity increase of over 120%.

[0049] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A capacity-enhancing conductor for a photovoltaic system, characterized in that, It includes a carbon fiber core assembly and a soft aluminum conductor covering the outside of the carbon fiber core assembly. The carbon fiber core assembly is formed by stranding multiple carbon fiber composite cores, and each carbon fiber composite core is coated by impregnation.

2. The photovoltaic system expansion conductor according to claim 1, characterized in that, The carbon fiber composite core comprises the following raw materials by weight: 80-120 parts acrylonitrile, 2-3 parts epoxy resin, 40-60 parts carbon fiber, 1-2 parts first curing agent and 2-3 parts diluent.

3. The photovoltaic system expansion conductor according to claim 1, characterized in that, The inner diameter of the soft aluminum conductor is larger than the outer diameter of the carbon fiber composite core.

4. A method for manufacturing a capacity-enhancing conductor for a photovoltaic system, characterized in that, Includes the following steps: To prepare a carbon fiber composite core, the prepared multi-strand carbon fiber composite core is twisted together to obtain a carbon fiber core assembly. Tension is applied to the carbon fiber core assembly, and a soft aluminum conductor is stranded in a frame around the outside of the stretched carbon fiber core assembly. The soft aluminum conductor is coaxially arranged with the carbon fiber core assembly, and the capacity expansion wire for photovoltaic system is finally obtained.

5. The method for manufacturing a capacity-enhancing conductor for a photovoltaic system according to claim 4, characterized in that, The steps for preparing the carbon fiber composite core are as follows: Preparation of resin mixture system: Weigh acrylonitrile and dimethyl sulfoxide solvent, mix them, heat to 60-70℃, stir for 30-40 min, then add epoxy resin and stir for 30-40 min while maintaining at 60-70℃ to obtain the first mixture system; Carbon fiber pretreatment: Weigh the carbon fiber, add it to dimethylacetamide solvent, heat to 50°C, stir under ultrasonic conditions for 30-35 minutes, and then mix it with the first mixing system to obtain the second mixing system; Composite curing: Add the first curing agent and diluent to the obtained second mixture system, stir evenly, and let stand at room temperature for 3-5 hours to obtain product A; Oxidation and carbonization treatment: First, the obtained product A is placed in an oxidation furnace for pre-oxidation at 200-300℃ for 1-2 hours. Then, product A is carbonized at a low temperature of 400℃-800℃, and then carbonized at a high temperature of 1000℃-2000℃. Finally, the carbon fiber composite core is formed by sequential qualitative and drawing processes. The carbon fiber composite core is then dried and pretreated before being inserted into an impregnation tank under the tension of a traction machine. The coating is made of resin material, which completely covers and reinforces the carbon fiber composite core.

6. The method for manufacturing a capacity-enhancing conductor for a photovoltaic system according to claim 4 or 5, characterized in that, The resulting carbon fiber composite core has a tensile strength ≥3500 MPa, a tensile modulus of elasticity of 260-430 GPa, and a longitudinal coefficient of thermal expansion ≤1.0×10⁻⁶. -6 / ℃, transverse thermal expansion coefficient ≤1.8×10 -6 / ℃.

7. The method for manufacturing a capacity-enhancing conductor for a photovoltaic system according to claim 5, characterized in that, The resin material comprises the following raw materials by weight: 100 parts thermosetting resin, 50-150 parts second curing agent, 1-20 parts accelerator and 1-20 parts release agent.

8. The method for manufacturing a capacity-enhancing conductor for a photovoltaic system according to claim 7, characterized in that, The thermosetting resin includes one or more of epoxy resin, polyester resin, and vinyl ester.

9. The method for manufacturing a capacity-enhancing conductor for a photovoltaic system according to claim 4, characterized in that, The obtained capacity-enhancing wire has a conductivity ≥62% IACS, a tensile strength of 80-85MPa, and an elongation of 30-35%.

10. The method for manufacturing a capacity-enhancing conductor for a photovoltaic system according to claim 4, characterized in that, When pre-stressing the carbon fiber composite core, the pre-stress is 40-50% of the total tensile strength of the carbon fiber composite core, and the pre-stressing time is 0.5-1 min.

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