Lightweight flame-retardant medium-voltage aluminum alloy cable for new energy charging station

Abstract

This invention discloses a lightweight, flame-retardant, medium-voltage aluminum alloy cable for new energy charging stations, relating to the field of aluminum alloy cable technology. It includes a cable core and an aluminum alloy armor layer and an outer sheath layer sequentially wrapped around the cable core from the inside out. The aluminum alloy armor layer consists of an inner armor layer and several outer armor layers fitted onto the inner armor layer. The two ends of the outer armor layers are slidably connected to the inner armor layers, and a thermal expansion agent is filled between adjacent outer armor layers. The inner surface of the outer armor layer has several annularly distributed guide rods, and the inner armor layer has several grooves corresponding to and slidably sealed to the guide rods. Component B is encapsulated in the grooves, and component A is encapsulated in the guide rods. The lower end of the guide rods has a valve that allows component B to enter component A to react and release the flame-retardant material. This invention improves the flame-retardant performance of the aluminum alloy cable by creating a chemical-physical protective barrier through the interlocking of the thermal expansion agent and the outer armor layer.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy cable technology, specifically to a lightweight, flame-retardant, medium-voltage aluminum alloy cable for new energy charging stations. Background Technology

[0002] With the continuous increase in the number of electric vehicles, the total number of charging infrastructure in my country has exceeded 20.698 million charging stations. The surge in demand for public charging piles is forcing the construction of charging stations to evolve towards high density, high safety, and low cost. Traditional copper core cables have become increasingly expensive due to the price of copper exceeding 100,000 yuan / ton since 2024, more than doubling the price difference with aluminum (approximately 25,000 yuan / ton). This has increased the material cost of a single 10-car fast charging station by over 150,000 yuan, forcing the industry to accelerate the "aluminum-for-copper" process—currently, the application rate of aluminum alloy cables in small and medium-sized charging stations has reached 60% to 70%.

[0003] Meanwhile, with the large-scale construction of charging stations, the safety of cable use is particularly important. Currently, cables still face risks such as flammability, which directly threaten the safety of charging station personnel and the integrity of equipment. In order to improve the safety of medium-voltage aluminum alloy cables, a lightweight flame-retardant medium-voltage aluminum alloy cable is needed to solve the above problems. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a lightweight, flame-retardant, medium-voltage aluminum alloy cable for new energy charging stations.

[0005] The technical solution of this invention is: a lightweight flame-retardant medium-voltage aluminum alloy cable for new energy charging stations, comprising a cable core, and an aluminum alloy armor layer and an outer sheath layer sequentially wrapped around the cable core from the inside out. The cable core is composed of multiple power wire cores and cable core filler material twisted together. The aluminum alloy armor layer consists of an inner armor sleeve and several outer armor sleeves sleeved on the inner armor sleeve. The two ends of the outer armor sleeves are slidably connected to the inner armor sleeves, and a thermal expansion agent is filled between two adjacent outer armor sleeves. The inner side of the outer armor sleeve has several ring-shaped guide rods, and the inner armor sleeve has several grooves that correspond one-to-one with the guide rods and are slidably sealed. The grooves are encapsulated with component B, the guide rods are encapsulated with component A, and the lower end of the guide rod (33) has a valve that uses the guide rod to lift the component B into the component A to react and release the flame retardant material. Component A is a mixture of 85-90 wt% polyol and 10-15 wt% flame retardant; component B is isocyanate, and the volume ratio of component A to component B is 1-1.5:1.

[0006] Furthermore, the inner armor sleeve is made of hard aluminum alloy, and the outer armor sleeve is made of soft aluminum alloy. The hard aluminum alloy is a 5-series or 6-series aluminum alloy, and the soft aluminum alloy is a 1-series aluminum alloy.

[0007] Note: Since the inner armor sleeve mainly serves as the core structural layer of the aluminum alloy armor layer, a 5-series aluminum alloy, such as 5052 aluminum alloy, is sufficient. Its tensile strength is 280±10MPa, and its elongation is controlled within 5%~8%, combining high strength, good formability, and excellent corrosion resistance. The outer armor sleeve, on the other hand, mainly serves as the responsive functional layer of the aluminum alloy armor layer. It needs to bend and arch in response to the expansion of the thermal expansion agent. Therefore, it requires good hardness to meet the usage requirements of the outer armor sleeve. A 1-series aluminum alloy, such as 1050 or 1100 aluminum alloy, can meet this requirement. Its hardness is HV15~25, elongation >30%, and yield strength <50 MPa. With a guide rod added in the middle, the strength in the middle is higher than on the sides, allowing it to bend and arch in response to the expansion of the thermal expansion agent.

[0008] Furthermore, the inner armor sleeve has a thickness of 2-3 mm, the outer armor sleeve has a length of 5-8 cm and a thickness of 1-2 mm; the gap between the two outer armor sleeves is 0.5-1 cm; and the filling area of ​​the thermal expansion agent is an annular region with a width of 0.5-1 cm and a thickness of 1-2 mm, the same as the gap, with a filling density of 0.7-0.8 g / cm³. 3 And aluminum foil is used to seal the edges of the thermal expansion agent.

[0009] Note: With the above-mentioned dimensions of the outer armor sleeve and the use of 1-series aluminum alloy, along with the above-mentioned amount of thermal expansion agent, the combined effect of both can effectively meet the response requirements of bending and arching due to the expansion of the thermal expansion agent.

[0010] Furthermore, the thermal expansion agent is an intumescent flame retardant IFR or intumescent graphite, wherein the intumescent flame retardant IFR is composed of ammonium polyphosphate, pentaerythritol, melamine, and titanium dioxide in a mass ratio of 46~50:22~25:18~20:5~14.

[0011] Note: The above-mentioned intumescent flame retardant IFR or intumescent graphite can meet the requirement of thermal expansion response at 120~160℃. Taking intumescent flame retardant IFR as an example, the intumescent flame retardant IFR has a fast response effect and can quickly expand thermally, thereby causing the outer armor sheath to bend and arch, so that the cable can quickly achieve physical isolation response when it is close to the heat source area.

[0012] Furthermore, by mass fraction, the cable core filling material comprises 10-18 parts aluminum hydroxide, 20-30 parts aluminum silicate fiber, and 3-5 parts 3A / 4A / 5A molecular sieve.

[0013] Explanation: Aluminum hydroxide (Al(OH)3) undergoes endothermic decomposition when heated above 205℃, absorbing approximately 1967 kJ / kg of latent heat, significantly reducing the material surface temperature and delaying polymer pyrolysis. Simultaneously, the released water vapor dilutes the oxygen concentration, inhibiting flame spread. The resulting alumina forms a dense, heat-insulating carbonized layer, preventing the escape of combustible gases. It is halogen-free, non-toxic, and does not produce corrosive gases. Alumina silicate fiber, as an inorganic refractory fiber, possesses extremely low thermal conductivity (0.035 W / m·K at room temperature), high temperature resistance (up to 1000–1350℃ for long-term use), and excellent resistance to mechanical vibration. Its fiber structure can fill the gaps in loose tubing, effectively supporting the cable core. 3A / 4A / 5A molecular sieves, being crystalline aluminosilicates, keep the cable core dry, reducing the impact of high humidity environments on cable functionality.

[0014] Furthermore, the outer sheath layer is one of polyvinyl chloride outer sheath, TPE outer sheath, FEP outer sheath, and PTFE outer sheath, with a thickness of 0.5~2mm.

[0015] Note: Polyvinyl chloride (PVC) outer sheath is one of the most mainstream outer sheath materials and is widely used in medium and low voltage aluminum alloy power cables. It has good flame retardancy, moisture resistance, wear resistance and low cost advantages, and is suitable for laying in buildings, direct burial and bracket installation. TPE outer sheath is designed for dynamic laying scenarios, such as new energy vehicle charging pile cables, robot drag chain systems, and mobile device power supply cables. TPE sheath has high elasticity, tear resistance, UV resistance, hydrolysis resistance, and low temperature toughness (up to -55℃). FEP and PTFE outer sheaths are used in harsh industrial environments such as petrochemical, aerospace, nuclear power and high-frequency signal transmission systems. The temperature resistance of FEP and PTFE sheaths can reach 200–250℃, and they are resistant to strong acids, strong alkalis and solvent corrosion, and have an extremely low coefficient of friction and are anti-adhesive.

[0016] Furthermore, the polyol is any one of polyether polyol or polyester polyol; the flame retardant is THPO.

[0017] Note: Polyether polyols have advantages such as low viscosity and high fluidity, excellent hydrolysis resistance, high processing tolerance, and excellent low-temperature performance. Polyester polyols have advantages such as excellent charring ability, high thermal stability, and strong synergistic effect with flame retardants. However, the polyether segments of polyether polyols themselves have weak charring ability and cannot form a dense char layer independently. They must rely on external flame retardants (such as THPO) to achieve UL94 V-0 flame retardancy. THPO contains ≥20.8% phosphorus and has three active hydroxymethyl groups (–CH2OH) in its molecule. It can be used as an initiator to copolymerize with polyols to form a chemically bonded flame-retardant structure. It has no migration or precipitation, excellent flame-retardant durability, and is free of chlorine and bromine. It produces no corrosive smoke when burning and is non-carcinogenic. It complies with RoHS and REACH standards. It has excellent thermal stability and hydrolysis resistance, and catalytically dehydrates and carbonizes in the condensed phase to form a dense, high-carbon-residue insulation layer. This makes the polyurethane foam oxygen index >30%, easily achieving UL94 V-0 rating without sacrificing mechanical properties.

[0018] Furthermore, both the inner and outer armor layers are coated with a smart-responsive nano-self-extinguishing coating. The method for applying the smart-responsive nano-self-extinguishing coating is as follows: 1) Pretreatment: Argon plasma bombardment was performed on the outer and inner armor sleeves for 5 min at 500~600W radio frequency power. Then, low-temperature plasma nitriding pretreatment was performed on the outer and inner armor sleeves for 10 min at 100~120W radio frequency power. 2) Precursor gas: A five-component synchronous injection mode is adopted. The flow ratio of the precursor gas is: NbCl5:NH3:urea:HDI:polyol = 0.5~1.5:2.5~3.5:1.5~2.5:1.2~1.8:1~1.5, in mL / min; 3) Plasma-assisted chemical vapor deposition: Radio frequency capacitively coupled discharge (13.56 MHz) is used to activate the precursor gas in a low-pressure environment of <5 Pa, forming a high-energy electron cloud (electron temperature >10°C). 4 K), so that the deposition temperature is controlled at 200~280℃, and the five components are simultaneously introduced into the deposition chamber. Under the gas flow ratio and 300~500W radio frequency power, the pre-treated outer armor sleeve and the pre-treated inner armor sleeve are co-deposited for 15~45min (corresponding to 1~5μm thickness).

[0019] Note: Due to the natural oxide layer on the surface of aluminum alloy, which has high chemical inertness, direct deposition can easily lead to insufficient adhesion (<5 MPa). To ensure coating adhesion >15 MPa, the outer and inner armor layers are bombarded with argon plasma to remove surface organic contaminants and loose oxides, introducing a nanoscale roughness Ra ≈ 80~120 nm to increase the effective contact area and activate surface hydroxyl groups (-OH) to provide sites for subsequent chemical bonding. Then, a low-temperature plasma nitriding pretreatment is performed to form a thin layer of aluminum nitride (AlN) with a thickness of approximately 20 nm on the surface, serving as a transition buffer layer to alleviate the thermal stress mismatch between NbN (coefficient of thermal expansion 7 ppm / K) and aluminum alloy (23 ppm / K). A smart responsive self-extinguishing nano-coating (NbN / GCN / PU system) is introduced onto the surface of the outer and inner layers of armored fire protection systems using PACVD to construct a smart responsive flame-retardant barrier. This barrier consists of nano-niobium nitride (NbN) and graphitic carbon nitride (GCN) embedded in a polyurethane (PU) matrix. At high temperatures (>200℃), a smart response mechanism is triggered. The nano-NbN rapidly carbonizes and expands, forming a dense ceramic-based heat insulation layer. The GCN releases non-combustible gases (such as NH3 and N2), diluting the oxygen concentration. The PU matrix undergoes cross-linking and curing, forming a continuous carbon skeleton that blocks heat conduction and flame spread. The overall system constitutes a multi-layered fire extinguishing mechanism: heat triggering, self-carbonization, gas asphyxiation, and heat and oxygen isolation.

[0020] Furthermore, the gas used in the low-temperature plasma nitriding pretreatment is an N2 / H2 mixed gas, and the N2:H2 flow ratio in the N2 / H2 mixed gas is 8~9:2~1, with units of mL / min.

[0021] Note: By using the N2 / H2 mixed gas with the above ratio, the surface oxygen content can be effectively reduced, the nitrogen plasma activity can be enhanced, and the uniform nucleation of the AlN layer can be promoted.

[0022] Furthermore, the purity of the NbCl5 is ≥99.99%, the NH3 is high-purity NH3, and the HDI and polyol are preheated to 80°C to maintain a liquid vapor state.

[0023] Note: The NbN component uses niobium pentachloride (NbCl5) as the niobium source and ammonia (NH3) as the nitrogen source, and the reaction occurs under the action of plasma: NbCl5 + NH3 → NbN + HCl↑ The GCN component uses urea (CO(NH2)2) as a precursor, which is pyrolyzed by plasma to generate cyanamide (H2N–C≡N) intermediate, which is further polymerized to form a graphitic carbon nitride network; The PU matrix is ​​formed by in-situ crosslinking of a mixture of hexamethylene diisocyanate (HDI) and polyol under low-temperature plasma induction, resulting in a polyurethane elastic network.

[0024] The beneficial effects of this invention are: (1) The lightweight flame-retardant medium-voltage aluminum alloy cable of the present invention uses an inner armored sheath and an outer armored sheath with different hardness as the main physical protective layers. The thermal expansion agent and the outer armored sheath (component A + component B) form a chemical-physical protective barrier that responds when the cable is subjected to a high temperature of 100~160℃, so as to reduce the possibility of cable chain fire damage and improve the flame-retardant performance of medium-voltage aluminum alloy cable.

[0025] (2) The present invention provides a lightweight flame-retardant medium-voltage aluminum alloy cable that, while constructing a chemical-physical protective barrier dominated by thermal expansion agent and armored outer sheath (component A + component B), introduces an intelligent responsive nano self-extinguishing coating into the surface of the armored outer sheath and armored inner sheath to construct an intelligent responsive flame-retardant barrier. The whole structure constitutes a multi-fire extinguishing mechanism of thermal triggering-self-carbonization-gas asphyxiation-heat insulation and oxygen isolation, further improving the flame-retardant performance of the medium-voltage aluminum alloy cable. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a medium-voltage aluminum alloy cable; Figure 2 This is a schematic diagram of the normal structure of the aluminum alloy armor layer; Figure 3 This is a schematic diagram of the flame-retardant structure of the aluminum alloy armor layer; Figure 4 This is a schematic diagram showing the assembly relationship between the guide rod and the sinker. Among them, 1-power core, 2-cable core filler material, 3-aluminum alloy armor layer, 31-inner armor sleeve, 32-outer armor sleeve, 33-guide rod, 34-sinking groove, 4-thermal expansion agent, and 5-outer sheath layer. Detailed Implementation

[0027] The present invention will now be described in more detail with reference to specific embodiments, so as to better demonstrate the advantages of the present invention.

[0028] Example 1: A lightweight, flame-retardant, medium-voltage aluminum alloy cable for new energy charging stations, mainly used in areas where charging stations are buried or where cable laying does not require frequent bending, such as... Figure 1 As shown, the cable mainly includes a cable core, and an aluminum alloy armor layer and an outer sheath layer 5 that are sequentially wrapped around the cable core from the inside out. It should be noted that the aluminum alloy cable may also include conventional functional layers such as an insulation layer. For example, a polyvinyl chloride insulation layer may be set between the cable core and the aluminum alloy armor layer. This is not limited. The outer sheath layer 5 is a TPE outer sheath with a thickness of 1.5mm. The TPE outer sheath is designed for dynamic laying scenarios, such as new energy vehicle charging pile cables, robot drag chain systems, and mobile device power supply cables. The TPE sheath has high elasticity, tear resistance, UV resistance, hydrolysis resistance, and low temperature toughness (up to -55℃). The cable core is composed of three power wire cores 1 and cable core filling material 2 twisted together; by mass parts, the cable core filling material 2 includes 16 parts aluminum hydroxide, 25 parts aluminum silicate fiber and 4 parts 3A molecular sieve, and aluminum hydroxide, aluminum silicate fiber and 3A molecular sieve are all commercially available. The aluminum alloy armor layer consists of an inner armor sleeve 31 and several outer armor sleeves 32 fitted onto the inner armor sleeve 31. The two ends of each outer armor sleeve 32 are slidably connected to the inner armor sleeve 31, and a thermal expansion agent 4 is filled between adjacent outer armor sleeves 32. The inner armor sleeve 31 has a thickness of 2.5 mm, and the outer armor sleeve 32 has a length of 6 cm and a thickness of 1.5 mm. The gap between two outer armor sleeves 32 is 0.8 cm. The thermal expansion agent 4 is filled in an annular region with a width of 0.8 cm and a thickness of 1.5 mm, the same as the gap, with a filling density of 0.78 g / cm³. 3 And use commercially available aluminum foil to seal the edge of the thermal expansion agent 4. It should be noted that sealing the edge refers to sealing the outer ring surface of the thermal expansion agent 4 exposed by the aluminum foil, so as to facilitate the subsequent wrapping of the outer sheath layer 5. The outer armor sleeve 32 has several annularly distributed guide rods 33 on its inner side, and the inner armor sleeve 31 has several grooves 34 that correspond one-to-one with the guide rods 33 and are slidably and sealingly connected. Component B is encapsulated within each groove 34, and component A is encapsulated within each guide rod 33. This is used to lift the guide rods 33, allowing component B to enter component A and react to release the flame-retardant material. Figure 2 , Figure 3 As shown; Component A is a mixture of 88 wt% polyol and 12 wt% flame retardant. In this embodiment, the polyol is a polyether polyol; the flame retardant is THPO; and component B is an isocyanate. In this embodiment, commercially available TDI is used, but other commercially available liquid isocyanates may also be used, not specifically this one. The volume ratio of component A to component B is 1.2:1. The thermal expansion agent 4 is an intumescent flame retardant IFR, wherein the intumescent flame retardant IFR is composed of ammonium polyphosphate, pentaerythritol, melamine, and titanium dioxide in a mass ratio of 49:23:19:9.

[0029] The inner armor sleeve 31 is made of hard aluminum alloy, and the outer armor sleeve 32 is made of soft aluminum alloy. The hard aluminum alloy is 5 series, such as commercially available 5052 aluminum alloy, and the soft aluminum alloy is 1 series aluminum alloy, such as commercially available 1100 aluminum alloy.

[0030] It should be noted that the aluminum alloy armor layer is a prefabricated component, meaning that the outer armor sleeve 32 and the thermal expansion agent 4 are pre-installed on the inner armor sleeve 31, and the thermal expansion agent 4 is sealed with aluminum foil. Meanwhile, the guide rod 33 is made of the same 5-series aluminum alloy as the hard aluminum alloy, and is installed through the rod hole of the outer armor sleeve 32 and assembled with the corresponding recess 34. The lower end of the guide rod 33 has a pull-open valve, and the recess 34 has a protrusion that locks the valve flange. Correspondingly, the valve flange has a notch that mates with the protrusion, and the inner end of the valve is connected to a piston plate via a connecting rod. The outer end face of the valve has a guide hole that communicates with the internal flow path of the connecting rod. The upper end of the guide rod 33 has a limiting ring welded to the rod hole. Figure 4 As shown, after the guide rod 33 is raised, the piston plate moves relative to the guide rod, and the air inside it (the air in the cavity between the piston plate and the bottom surface of the guide rod) is forced into the settling tank through the exhaust port with a commercially available one-way valve / check valve. Under the action of air pressure, component B of the settling tank 34 enters the guide rod 33 through the guide hole and the commercially available one-way valve / check valve built into the guide hole and the internal flow path of the connecting rod, and mixes with component A.

[0031] Meanwhile, it should be noted that the outer sheath layer 5 should preferably be made of an elastic outer sheath material, or its covering thickness should be reduced to provide conditions for the outer arch deformation of the armor outer layer 32. When burying, it is recommended to fill the top and bottom 5cm of the cable laying layer with soft sand, or to avoid ground subsidence, support structures can be laid at fixed points around the cable to ensure that the sand is not compacted before laying the cable, so as to provide conditions for the outer arch deformation of the armor outer layer 32.

[0032] Example 2: This example differs from Example 1 in that the outer sheath layer 5 has a thickness of 0.5 mm; the inner armor layer 31 has a thickness of 2 mm; the outer armor layer 32 has a length of 5 cm and a thickness of 1 mm; the gap between the two outer armor layers 32 is 0.5 cm; and the filling area of ​​the thermal expansion agent 4 is an annular area with a width of 0.5 cm and a thickness of 1 mm, the same as the gap, with a filling density of 0.7 g / cm³. 3 .

[0033] Example 3: This example differs from Example 1 in that the outer sheath layer 5 has a thickness of 2mm; the inner armor layer 31 has a thickness of 3mm; the outer armor layer 32 has a length of 8cm and a thickness of 2mm; the gap between the two outer armor layers 32 is 1cm; and the filling area of ​​the thermal expansion agent 4 is an annular area with a width of 1cm and a thickness of 2mm, the same as the gap, with a filling density of 0.8 g / cm³. 3 .

[0034] Example 4: This example differs from Example 1 in that, by mass parts, the cable core filling material 2 includes 10 parts aluminum hydroxide, 20 parts aluminum silicate fiber and 3 parts 3A molecular sieve.

[0035] Example 5: This example differs from Example 1 in that, by mass parts, the cable core filling material 2 includes 18 parts aluminum hydroxide, 30 parts aluminum silicate fiber and 5 parts 3A molecular sieve.

[0036] Example 6: This example differs from Example 1 in that component A is a mixture of 85 wt% polyol and 15 wt% flame retardant, and the volume ratio of component A to component B is 1:1.

[0037] Example 7: This example differs from Example 1 in that component A is a mixture of 90 wt% polyol and 10 wt% flame retardant, and the volume ratio of component A to component B is 1.5:1.

[0038] Example 8: The difference between this example and Example 1 is that the intumescent flame retardant IFR is composed of ammonium polyphosphate, pentaerythritol, melamine, and titanium dioxide in a mass ratio of 46:22:18:5.

[0039] Example 9: The difference between this example and Example 1 is that the intumescent flame retardant IFR is composed of ammonium polyphosphate, pentaerythritol, melamine, and titanium dioxide in a mass ratio of 50:25:20:14.

[0040] Example 10: The difference between this example and Example 1 is that the thermal expansion agent 4 is commercially available expanded graphite.

[0041] Example 11: This example differs from Example 1 in that both the inner armor sleeve 31 and the outer armor sleeve 32 are coated with a smart responsive nano self-extinguishing coating. The method for applying the smart responsive nano self-extinguishing coating is as follows: 1) Pretreatment: Argon plasma bombardment was performed on the outer armor sleeve 32 and the inner armor sleeve 31 at 550W radio frequency power for 5 minutes. Then, the outer armor sleeve 32 and the inner armor sleeve 31 were subjected to low temperature plasma nitriding pretreatment at 110W radio frequency power for 10 minutes. The gas used in the low-temperature plasma nitriding pretreatment is an N2 / H2 mixed gas, and the N2:H2 flow ratio in the N2 / H2 mixed gas is 85:15, with units of mL / min; 2) Precursor gas: A five-component synchronous injection mode is adopted, and the flow ratio of the precursor gas is: NbCl5:NH3:urea:HDI:polyol = 1:3:2:1.5:1.2, in mL / min; The purity of the NbCl5 is ≥99.99%, the NH3 is high-purity NH3, and the HDI and polyol are preheated to 80°C to maintain a liquid vapor state. The NbN component reacts under plasma conditions using niobium pentachloride (NbCl5) as the niobium source and ammonia (NH3) as the nitrogen source: NbCl5 + NH3 → NbN + HCl↑ The GCN component uses urea (CO(NH2)2) as a precursor, which is pyrolyzed by plasma to generate cyanamide (H2N–C≡N) intermediate, which is further polymerized to form a graphitic carbon nitride network; The PU matrix is ​​formed by in-situ crosslinking of a mixed vapor of hexamethylene diisocyanate (HDI) and polyol under low-temperature plasma induction to form a polyurethane elastic network. 3) Plasma-assisted chemical vapor deposition: Radio frequency capacitively coupled discharge (13.56 MHz) is used to activate the precursor gas in a low-pressure environment of <5 Pa, forming a high-energy electron cloud (electron temperature >10°C). 4 K), the deposition temperature was controlled at 220℃, and the five components were simultaneously introduced into the deposition chamber. Under the specified gas flow rate ratio and 460W RF power, the pretreated outer armor sleeve 32 and the pretreated inner armor sleeve 31 were co-deposited for 35 minutes, corresponding to a thickness of 4μm.

[0042] Example 12: The difference between this example and Example 11 is that in 1), the outer armor sleeve 32 and the inner armor sleeve 31 are bombarded with argon plasma for 5 minutes at 500W radio frequency power; then the outer armor sleeve 32 and the inner armor sleeve 31 are subjected to low-temperature plasma nitriding pretreatment for 10 minutes at 100W radio frequency power.

[0043] Example 13: The difference between this example and Example 11 is that in 1), the outer armor sleeve 32 and the inner armor sleeve 31 are bombarded with argon plasma and processed at 600W radio frequency power for 5 minutes; then the outer armor sleeve 32 and the inner armor sleeve 31 are subjected to low-temperature plasma nitriding pretreatment and processed at 120W radio frequency power for 10 minutes.

[0044] Example 14: The difference between this example and Example 11 is that, in 1), the flow ratio of N2:H2 in the N2 / H2 mixed gas is 8:2, in mL / min.

[0045] Example 15: The difference between this example and Example 11 is that, in 1), the flow ratio of N2:H2 in the N2 / H2 mixed gas is 9:1, in mL / min.

[0046] Example 16: The difference between this example and Example 11 is that in 2), the flow rate ratio of the precursor gas is: NbCl5:NH3:urea:HDI:polyol = 0.5:2.5:1.5:1.8:1.5, in mL / min.

[0047] Example 17: The difference between this example and Example 11 is that in 2), the flow rate ratio of the precursor gas is: NbCl5:NH3:urea:HDI:polyol = 1.5:3.5:2.5:1.2:1, in mL / min.

[0048] Example 18: The difference between this example and Example 11 is that in step 3), the deposition temperature is controlled at 200°C, the five components are simultaneously introduced into the deposition chamber, and the pre-treated outer armor sleeve 32 and the pre-treated inner armor sleeve 31 are co-deposited for 15 minutes at the gas flow rate ratio and 300W RF power.

[0049] Example 19: The difference between this example and Example 11 is that in step 3), the deposition temperature is controlled at 280°C, the five components are simultaneously introduced into the deposition chamber, and the pre-treated outer armor sleeve 32 and the pre-treated inner armor sleeve 31 are co-deposited for 45 minutes at the gas flow rate ratio and 500W RF power.

[0050] Experimental example: To verify the performance of the lightweight flame-retardant medium-voltage aluminum alloy cable of the present invention, experimental tests were conducted on the lightweight flame-retardant medium-voltage aluminum alloy cable, and a comparative example was also set up, as follows: Comparative Example 1: Traditional flame-retardant cable (pure copper conductor (≥99.9%) + XLPE insulation + ZC-grade flame-retardant sheath), ZC grade (GB / T 19666-2019).

[0051] The oxygen index (LOI) and burning duration (Tc) were used to test lightweight flame-retardant medium-voltage aluminum alloy cables (Example 1) and traditional flame-retardant cables. The test methods are shown in Table 1 below: Table 1. Test methods for Oxygen Index (LOI) and Combustion Duration (Tc)

[0052] Note: The test environment temperature was 23±2℃ and the humidity was 50±5%.

[0053] The test results are shown in Table 2 below: Table 2. Test results of Oxygen Index (LOI) and Combustion Duration (Tc)

[0054] As can be seen from the results in Table 2 above, the oxygen index (LOI) and burning duration (Tc) of the lightweight flame-retardant medium-voltage aluminum alloy cable of the present invention are significantly better than those of traditional flame-retardant cables, and the flame-retardant performance is significantly enhanced.

[0055] To further verify the performance of the lightweight flame-retardant medium-voltage aluminum alloy cable, the following investigation was conducted: Investigation 1: The effect of component A content on lightweight flame-retardant medium-voltage aluminum alloy cables. Oxygen index (LOI) and duration of combustion (Tc) were tested on Examples 6 and 7. Comparative Example 2 was also included. Comparative Example 2 was essentially the same as Example 1, except that the aluminum alloy armor layer consisted only of the inner armor layer, without the thermal expansion agent and the outer armor layer (component A + component B). The test results are shown in Table 3 below. Table 3. Test results of Oxygen Index (LOI) and Combustion Duration (Tc)

[0056] As can be seen from the results in Table 3 above, the oxygen index (LOI) and burning duration (Tc) of the lightweight flame-retardant medium-voltage aluminum alloy cables in each embodiment are significantly better than those of traditional flame-retardant cables, and the flame-retardant performance is significantly enhanced. Among them, the A group in Example 1 is relatively optimal. However, after removing the thermal expansion agent and the armored outer sheath (component A + component B), the flame-retardant performance decreased significantly. It can be seen that the interlocking structure of the thermal expansion agent and the armored outer sheath (component A + component B) forms a chemical-physical protective barrier that responds when the cable is subjected to a high temperature of 100~160℃, which can reduce the possibility of cable chain fire damage and improve the flame-retardant performance of aluminum alloy cables.

[0057] Investigation 2: The effect of different thermal expansion agents on lightweight flame-retardant medium-voltage aluminum alloy cables. Oxygen index (LOI) and duration of combustion (Tc) were tested on Examples 8, 9, and 10. The test results are shown in Table 4 below: Table 4. Test results of Oxygen Index (LOI) and Combustion Duration (Tc)

[0058] As can be seen from the results in Table 4 above, the intumescent flame retardant IFR of the present invention has a more ideal response triggering speed. Since the thermal aging temperatures of components A and B are between 180 and 200°C, the faster the temperature response, the better the chain effect of the thermal expansion agent and the armored outer layer (component A + component B). Through comparison, it can be seen that the intumescent flame retardant IFR in Example 1 has the best performance.

[0059] Investigation 3: The effect of intelligent responsive nano self-extinguishing coating on lightweight flame-retardant medium-voltage aluminum alloy cables. Oxygen index (LOI) and duration of combustion (Tc) were tested on Examples 11-19. The test results are shown in Table 5 below: Table 5. Results of Oxygen Index (LOI) and Combustion Duration (Tc) Tests

[0060] As can be seen from the results in Table 5 above, the flame retardant performance of the inner and outer armored sheaths was further enhanced after treatment with a smart responsive nano self-extinguishing coating, especially the combustion duration was significantly shortened. It is evident that the NbN / GCN / PU system constitutes a multi-layered fire extinguishing mechanism of thermal triggering, self-carbonization, gas asphyxiation, and heat and oxygen insulation, which significantly improves the flame retardant performance of the cable. By comparison, it can be seen that the lightweight flame retardant medium-voltage aluminum alloy cable of Example 19 has the best performance. Meanwhile, the operation time of Examples 11 and 13 is relatively shortened, but they still have good performance. From the perspective of economy, Example 11 has a better overall effect.

Claims

1. A lightweight, flame-retardant, medium-voltage aluminum alloy cable for new energy charging stations, characterized in that... It includes the cable core, and an aluminum alloy armor layer (3) and an outer sheath layer (5) that are wrapped around the cable core from the inside out. The cable core is composed of multiple power wire cores (1) twisted together with cable core filling material (2); The aluminum alloy armor layer (3) consists of an inner armor sleeve (31) and several outer armor sleeves (32) sleeved on the inner armor sleeve (31). The two ends of the outer armor sleeve (32) are slidably connected to the inner armor sleeve (31), and a thermal expansion agent (4) is filled between two adjacent outer armor sleeves (32). The inner side of the outer armor sleeve (32) has several ring-shaped guide rods (33), and the inner armor sleeve (31) has several grooves (34) that correspond one-to-one with the guide rods (33) and are slidably sealed. The grooves (34) contain component B, the guide rods (33) contain component A, and the lower end of the guide rods (33) has a valve that allows component B to enter component A to react and release flame retardant material by lifting the guide rods (33). Component A is a mixture of 85-90 wt% polyol and 10-15 wt% flame retardant; component B is isocyanate, and the volume ratio of component A to component B is 1-1.5:

1.

2. The lightweight flame-retardant medium-voltage aluminum alloy cable for new energy charging stations according to claim 1, characterized in that, The inner armor sleeve (31) is made of hard aluminum alloy, and the outer armor sleeve (32) is made of soft aluminum alloy. The hard aluminum alloy is a 5-series or 6-series aluminum alloy, and the soft aluminum alloy is a 1-series aluminum alloy.

3. The lightweight flame-retardant medium-voltage aluminum alloy cable for new energy charging stations according to claim 1, characterized in that, The inner armor sleeve (31) has a thickness of 2-3 mm, the outer armor sleeve (32) has a length of 5-8 cm and a thickness of 1-2 mm; the gap between the two outer armor sleeves (32) is 0.5-1 cm; and the filling area of ​​the thermal expansion agent (4) is an annular area with a width of 0.5-1 cm and a thickness of 1-2 mm, the same as the gap, with a filling density of 0.7-0.8 g / cm³. 3 And use aluminum foil to seal the edges of the thermal expansion agent (4).

4. The lightweight flame-retardant medium-voltage aluminum alloy cable for new energy charging stations according to claim 1, characterized in that, A thermal expansion agent (4) is filled between two adjacent outer armor sleeves (32). The thermal expansion agent (4) is an intumescent flame retardant IFR or an intumescent graphite. The intumescent flame retardant IFR is composed of ammonium polyphosphate, pentaerythritol, melamine, and titanium dioxide in a mass ratio of 46~50:22~25:18~20:5~14.

5. A lightweight flame-retardant medium-voltage aluminum alloy cable for new energy charging stations according to claim 1, characterized in that, By mass fraction, the cable core filling material (2) comprises 10-18 parts aluminum hydroxide, 20-30 parts aluminum silicate fiber and 3-5 parts 3A / 4A / 5A molecular sieve.

6. A lightweight flame-retardant medium-voltage aluminum alloy cable for new energy charging stations according to claim 1, characterized in that, The outer sheath layer (5) is one of polyvinyl chloride outer sheath, TPE outer sheath, FEP outer sheath, and PTFE outer sheath, with a thickness of 0.5~2mm.

7. A lightweight flame-retardant medium-voltage aluminum alloy cable for new energy charging stations according to claim 1, characterized in that, The polyol is either a polyether polyol or a polyester polyol; the flame retardant is THPO.

8. A lightweight flame-retardant medium-voltage aluminum alloy cable for new energy charging stations according to claim 1, characterized in that, The inner armor sleeve (31) and outer armor sleeve (32) are coated with a smart responsive nano self-extinguishing coating. The method for coating the smart responsive nano self-extinguishing coating is as follows: 1) Pretreatment: Argon plasma bombardment was performed on the outer armor sleeve (32) and the inner armor sleeve (31) for 5 min at 500~600W radio frequency power. Then, low temperature plasma nitriding pretreatment was performed on the outer armor sleeve (32) and the inner armor sleeve (31) for 10 min at 100~120W radio frequency power. 2) Precursor gas: A five-component synchronous injection mode is adopted. The flow ratio of the precursor gas is: NbCl5:NH3:urea:HDI:polyol = 0.5~1.5:2.5~3.5:1.5~2.5:1.2~1.8:1~1.5, in mL / min; 3) Plasma-assisted chemical vapor deposition: Radio frequency capacitive coupling discharge is used to activate the precursor gas in a low-pressure environment of <5Pa to form a high-energy electron cloud. The deposition temperature is controlled at 200~280℃. The five components are introduced into the deposition chamber simultaneously. Under the gas flow ratio and 300~500W radio frequency power, the pre-treated outer armor sleeve (32) and the pre-treated inner armor sleeve (31) are co-deposited for 15~45min.

9. A lightweight flame-retardant medium-voltage aluminum alloy cable for new energy charging stations according to claim 8, characterized in that, The gas used in the low-temperature plasma nitriding pretreatment is an N2 / H2 mixed gas, and the N2:H2 flow ratio in the N2 / H2 mixed gas is 8~9:2~1, with units of mL / min.

10. A lightweight flame-retardant medium-voltage aluminum alloy cable for new energy charging stations according to claim 8, characterized in that, The purity of the NbCl5 is ≥99.99%, the NH3 is high-purity NH3, and the HDI and polyol are preheated to 80°C to maintain a liquid vapor state.

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