A flexible cable for charging piles and its manufacturing method

Abstract

This application provides a flexible cable for charging piles and its manufacturing method, comprising a conductor core, a sheathing layer covering the outer periphery of the conductor core, a semiconductor shielding layer covering the outer periphery of the sheathing layer, an insulation layer covering the outer periphery of the semiconductor shielding layer, and a sheathing layer covering the outer periphery of the insulation layer. The conductor core is composed of multiple conductor monomers twisted together, wherein the conductor monomers are Cu, Al, Ag, and Cd alloys. By selecting Cd alloys as the constituent elements of the conductor monomers and twisting the multiple conductor monomers multiple times, the hardness of the conductor core is reduced and the elongation at break of the conductor core is increased. By selecting a composite sheathing layer material and preparing it together with the conductor core into a cable, the tightness of each layer structure of the cable is improved while the overall hardness is reduced. This has the advantages of facilitating the routing of new energy vehicle charging piles, making it easy for users to place and retrieve cables, greatly improving the user experience, and facilitating promotion and implementation.

Description

Technical Field

[0001] This application belongs to the technical field of cable manufacturing for charging piles, specifically relating to a flexible cable for charging piles and its manufacturing method. Background Technology

[0002] With the rapid development of semiconductor technology, new energy vehicles have been widely used. In order to meet the growing charging demand of new energy vehicles, the number of charging piles for new energy vehicles has increased significantly.

[0003] In existing technologies, conventional new energy vehicle charging pile cables use Category 5 conductors, which have high conductor hardness, low elongation at break, and poor ductility. These conductors are prone to breakage during frequent use. The internal layered structure of the cable is also prone to dispersion and has low density. On the one hand, in actual implementation, the high cable hardness makes it inconvenient to use during cable routing and handling, resulting in a poor user experience. On the other hand, it is difficult to produce, making it hard to ensure the concentricity of the various layers of the cable, and the cable has a short service life, which cannot meet people's needs. Therefore, there is an urgent need for improvement. Summary of the Invention

[0004] In order to solve the technical problems in the prior art, the conductor hardness of the cable for charging piles is too high, the overall hardness of the cable is too high after it is made into a cable, the internal layered structure of the cable is easy to disperse during the frequent use of the cable for charging piles, which makes it inconvenient for installers to run the cable, the user experience is poor when users take out and put away the charging cable, and the overall service life of the cable is short, this application proposes a flexible cable for charging piles.

[0005] To address the technical problems raised in this application, this application also provides a method for preparing a flexible cable for charging piles.

[0006] This application adopts the following scheme: a flexible cable for charging piles, comprising a conductor core, a wrapping layer covering the outer periphery of the conductor core, a semiconductor shielding layer covering the outer periphery of the wrapping layer, an insulation layer covering the outer periphery of the semiconductor shielding layer, and a sheathing layer covering the outer periphery of the insulation layer. The conductor core is formed by multiple strands of conductor units twisted together. By mass fraction, the conductor units are composed of the following components: 85-91% Cu, 5-8% Al, 2-3% Ag, and 2-3% Cd.

[0007] By modifying Cu with Al, Ag and Cd, Cd ions can be adsorbed on the surface of Cu crystal nuclei in the molten state, occupying the crystallization sites of Cu. Thus, without reducing the conductivity of the conductor, the mechanical properties of the conductor are changed after the molten alloy is formed, improving the conductor's ductility and flexibility.

[0008] Furthermore, the method for preparing the conductor monomer includes the following steps:

[0009] Step 101. Cu, Al and Ag are added to a vacuum melting furnace in the mass ratio. The furnace is heated from room temperature to 1150-1250℃ and stabilized at -0.01 MPa. After melting for 20-30 minutes, the molten alloy is obtained.

[0010] Step 102. After the molten alloy prepared in step 101 is cooled to 950-1000℃, excess Cd powder is sprayed into the molten alloy. After the molten alloy is cooled to 600-780℃, the spraying of Cd powder is stopped, and the pre-conductor is obtained.

[0011] Step 103. After the pre-conductor prepared in step 102 is subjected to continuous casting, wire drawing and annealing, the conductor monomer is obtained.

[0012] Furthermore, the annealing temperature in step 103 is 580-700℃.

[0013] Furthermore, the method for preparing the wire core includes the following steps:

[0014] Step 201. One twist

[0015] After placing the conductor unit on the active feeder, it is stranded once under the condition that the stranding ratio is 20 times and the stranding direction is to the left. Then it is transferred to the pressing die and pressed under the condition that the pressing coefficient is 2-2.5mm to obtain a single stranded conductor.

[0016] Step 202. Secondary twisting

[0017] The multiple primary stranded conductors prepared in step 201 are transferred to a 1+6 coil stranding device. After the primary stranded conductors are arranged in a regular 1+6 structure, they are stranded with a stranding pitch of 100-120mm, a stranding direction of left, and a stranding direction of right for the 1+6 structure. After stranding, they are transferred to a pressing mold and pressed with a pressing coefficient of 5.5-6mm to obtain a secondary stranded conductor.

[0018] Step 203. Three twists

[0019] The multi-strand secondary stranded conductors prepared in step 202 are transferred to a 19-coil stranding device. The secondary stranded conductors are arranged in a regular 1+6+12 structure and stranded in layers with a stranding pitch of 128-148mm. They are then transferred to a compaction mold and compacted with a compaction coefficient of 8.5-9.5mm to obtain the wire core.

[0020] Furthermore, step 203, layered stranding, includes the following steps: stranding the wires in the left-hand direction; after the strands are stranded and pressed tightly, stranding a 1+6 structure in the right-hand direction; after the 1+6 structure is stranded and pressed tightly, stranding a 1+6+12 structure in the left-hand direction; after the 1+6+12 structure is stranded and pressed tightly, the core wire is obtained.

[0021] Multiple strandings allow for tighter contact between conductor units, reducing gaps and further reducing conductor volume, resulting in a more compact core. This structure not only improves space utilization but also helps distribute stress during bending, reducing localized damage and making the cable more flexible and durable during installation and use. By using Cd-containing alloys as conductor unit components and stranding multiple conductor units multiple times, the core's hardness is reduced, while its elongation at break is increased. The use of composite sheath materials, combined with the core, enhances the tightness of the cable's layered structure while reducing overall hardness. This design facilitates cable routing for new energy vehicle charging stations, makes it easier for users to access and remove cables, significantly improves user experience, and facilitates widespread implementation.

[0022] By performing layered stranding in step 203, the internal stress between conductor units can be effectively eliminated. By changing the stranding direction, after eliminating the internal stress between conductor units, the tightness of the stranding between conductor units can be effectively improved, while reducing the overall hardness and improving the core elongation.

[0023] Furthermore, the wrapping layer is made of bulletproof yarn, and the weaving density of the wrapping layer is 95%-97%.

[0024] Furthermore, by weight, the sheath layer is composed of the following components: 30-45 parts polyvinylidene fluoride, 8-12 parts high-density polyethylene, 5-8 parts calcium carbonate, 2-5 parts graphene oxide, and 1-5 parts anhydrous ethanol.

[0025] Furthermore, the preparation method of the raw material for the sheath layer includes the following steps: polyvinylidene fluoride, high-density polyethylene, calcium carbonate, graphene oxide and anhydrous ethanol are sequentially added and dispersed evenly at high speed. The raw material mixture is then conveyed to an extruder and extruded, cooled and granulated under the conditions of -0.01 MPa, extruder head temperature of 90-100℃ and extruder screw speed of 1300 rpm to obtain the sheath material.

[0026] By using polyvinylidene fluoride (PVDF) and high-density polyethylene (HDPE) as the main components of the sheath layer, and adding graphene oxide, compared to the existing pure PVC sheath, PVDF groups are introduced into the long chain segments. This not only ensures the flame retardancy of the sheath layer, but also introduces flexible groups to improve the flexibility of the sheath layer and ensure the cable's ductility. Furthermore, by adding graphene oxide, the thermal conductivity of the cable can be effectively improved.

[0027] In order to solve the technical problems proposed in this application, this application also provides a method for preparing a flexible cable for charging piles, including the following steps: transferring the wire core with the outer circumference covered by the wrapping layer to the extrusion machine, and feeding the semiconductor shielding layer material, the insulation layer material and the sheath material into the extrusion machine in sequence, and extruding the semiconductor shielding layer, the insulation layer and the sheath layer in sequence from the inside to the outside of the wrapping layer.

[0028] Compared with the prior art, this application has the following beneficial effects:

[0029] This application provides a flexible cable for charging piles and its manufacturing method, comprising a conductor core, a sheathing layer covering the outer periphery of the conductor core, a semiconductor shielding layer covering the outer periphery of the sheathing layer, an insulation layer covering the outer periphery of the semiconductor shielding layer, and a sheathing layer covering the outer periphery of the insulation layer. The conductor core is composed of multiple conductor monomers twisted together, wherein the conductor monomers are Cu, Al, Ag, and Cd alloys. By selecting Cd alloys as the constituent elements of the conductor monomers and twisting the multiple conductor monomers multiple times, the hardness of the conductor core is reduced and the elongation at break of the conductor core is increased. By selecting a composite sheathing layer material and preparing it together with the conductor core into a cable, the tightness of each layer structure of the cable is improved while the overall hardness is reduced. This has the advantages of facilitating the routing of new energy vehicle charging piles, making it easy for users to place and retrieve cables, greatly improving the user experience, and facilitating promotion and implementation. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the cross-sectional structure of a flexible cable for a charging pile according to this application. Detailed Implementation

[0031] A flexible cable for charging piles includes a conductor core 1, a wrapping layer 2 covering the outer periphery of the conductor core 1, a semiconductor shielding layer 3 covering the outer periphery of the wrapping layer 2, an insulation layer 4 covering the outer periphery of the semiconductor shielding layer 3, and a sheath layer 5 covering the outer periphery of the insulation layer 4. The conductor core 1 is formed by multiple strands of conductor units 6 twisted together.

[0032] In this embodiment, the material of the wrapping layer is bulletproof wire, and the weaving density of the bulletproof wire is 96%.

[0033] In this embodiment, the semiconductor shielding layer is made of nickel-plated graphite fiber.

[0034] In this embodiment, the insulating layer is made of ethylene vinyl acetate copolymer.

[0035] Example 1

[0036] (I) The preparation method of the conductor monomer includes the following steps:

[0037] Step 101. According to the composition table shown in Table 1, Cu, Al and Ag are added to the vacuum melting furnace in the following mass ratio. The melting furnace is heated from room temperature to 1159°C, and the pressure is stabilized at -0.01 MPa. After melting for 30 minutes, the molten alloy is obtained.

[0038] Step 102. After the molten alloy prepared in step 101 is cooled to 966°C, excess Cd powder is injected into the molten alloy. After the molten alloy is cooled to 611°C, the injection of Cd powder is stopped, and the pre-conductor is obtained.

[0039] Step 103. The pre-conductor prepared in step 102 is subjected to continuous casting, wire drawing, and annealing at 588°C for 5 hours to obtain the conductor monomer.

[0040] (II) The preparation method of the wire core includes the following steps:

[0041] Step 201. One twist

[0042] After placing the conductor unit on the active feeder, it is stranded once under the condition that the stranding ratio is 20 times and the stranding direction is to the left. Then it is transferred to the compaction die and compacted under the condition that the compaction coefficient is 2.1mm to obtain a single stranded conductor.

[0043] Step 202. Secondary twisting

[0044] The multiple primary stranded conductors prepared in step 201 are transferred to a 1+6 coil stranding device. After the primary stranded conductors are arranged in a regular 1+6 structure, they are stranded with a stranding pitch of 108mm, a stranding direction of left and a stranding direction of right for the 1+6 structure. After being transferred to a pressing mold, they are pressed with a pressing coefficient of 5.5mm to obtain a secondary stranded conductor.

[0045] Step 203. Three twists

[0046] The multi-strand secondary stranded conductors prepared in step 202 are transferred to a 19-coil stranding device. The secondary stranded conductors are arranged in a regular 1+6+12 structure and stranded in layers with a stranding pitch of 130mm. They are then transferred to a compaction mold and compacted with a compaction coefficient of 8.9mm to obtain the wire core.

[0047] The layered stranding process includes the following steps: stranding the wires in the left-hand direction; after the strands are stranded and compressed, stranding a 1+6 structure in the right-hand direction; after the 1+6 structure is stranded and compressed, stranding a 1+6+12 structure in the left-hand direction; and after the 1+6+12 structure is stranded and compressed, the core wire is obtained.

[0048] (III) The preparation method of the sheath material includes the following steps:

[0049] According to the composition table shown in Table 1, polyvinylidene fluoride, high-density polyethylene, calcium carbonate, graphene oxide and anhydrous ethanol are added sequentially and dispersed evenly at high speed. The raw material mixture is then fed into an extruder and extruded, cooled and granulated under the conditions of -0.01 MPa, extruder head temperature of 91℃ and extruder screw speed of 1300 rpm to obtain the sheath material.

[0050] (iv) The method for preparing flexible cables for charging piles includes the following steps:

[0051] The wire core with the outer wrapping layer is transferred to the extrusion machine. The semiconductor shielding layer material, the insulating layer material and the sheath material are put into the extrusion machine in sequence. From the inside to the outside, the semiconductor shielding layer, the insulating layer and the sheath layer are extruded on the outer periphery of the wrapping layer in sequence.

[0052] Example 2

[0053] (I) The preparation method of the conductor monomer includes the following steps:

[0054] Step 101. According to the composition table shown in Table 1, Cu, Al and Ag are added to the vacuum melting furnace in the following mass ratio. The melting furnace is heated from room temperature to 1220℃, and the pressure is stabilized at -0.01 MPa. After melting for 25 minutes, the molten alloy is obtained.

[0055] Step 102. After the molten alloy prepared in step 101 is cooled to 970°C, excess Cd powder is injected into the molten alloy. After the molten alloy is cooled to 710°C, the injection of Cd powder is stopped, and the pre-conductor is obtained.

[0056] Step 103. The pre-conductor prepared in step 102 is subjected to continuous casting, wire drawing, and annealing at 645°C for 4.5 hours to obtain the conductor monomer.

[0057] (II) The preparation method of the wire core includes the following steps:

[0058] Step 201. One twist

[0059] After placing the conductor unit on the active feeder, it is stranded once under the condition that the stranding ratio is 20 times and the stranding direction is to the left. Then it is transferred to the pressing die and pressed under the condition that the pressing coefficient is 2.2mm to obtain a single stranded conductor.

[0060] Step 202. Secondary twisting

[0061] The multiple primary stranded conductors prepared in step 201 are transferred to a 1+6 coil stranding device. After the primary stranded conductors are arranged in a regular 1+6 structure, they are stranded with a stranding pitch of 110mm, a stranding direction of left and a stranding direction of right for the 1+6 structure. After being transferred to a pressing mold, they are pressed with a pressing coefficient of 5.7mm to obtain a secondary stranded conductor.

[0062] Step 203. Three twists

[0063] The multi-strand secondary stranded conductors prepared in step 202 are transferred to a 19-coil stranding device. The secondary stranded conductors are arranged in a regular 1+6+12 structure and stranded in layers with a stranding pitch of 133mm. They are then transferred to a compaction mold and compacted with a compaction coefficient of 8.9mm to obtain the wire core.

[0064] The layered stranding process includes the following steps: stranding the wires in the left-hand direction; after the strands are stranded and compressed, stranding a 1+6 structure in the right-hand direction; after the 1+6 structure is stranded and compressed, stranding a 1+6+12 structure in the left-hand direction; and after the 1+6+12 structure is stranded and compressed, the core wire is obtained.

[0065] (III) The preparation method of the sheath material includes the following steps:

[0066] According to the composition table shown in Table 1, polyvinylidene fluoride, high-density polyethylene, calcium carbonate, graphene oxide and anhydrous ethanol are added sequentially and dispersed evenly at high speed. The raw material mixture is then fed into an extruder and extruded, cooled and granulated under the conditions of -0.01 MPa, extruder head temperature of 95℃ and extruder screw speed of 1300 rpm to obtain the sheath material.

[0067] (iv) The method for preparing flexible cables for charging piles includes the following steps:

[0068] The wire core with the outer wrapping layer is transferred to the extrusion machine. The semiconductor shielding layer material, the insulating layer material and the sheath material are put into the extrusion machine in sequence. From the inside to the outside, the semiconductor shielding layer, the insulating layer and the sheath layer are extruded on the outer periphery of the wrapping layer in sequence.

[0069] Example 3

[0070] (I) The preparation method of the conductor monomer includes the following steps:

[0071] Step 101. According to the composition table shown in Table 1, Cu, Al and Ag are added to the vacuum melting furnace in the following mass ratio. The melting furnace is heated from room temperature to 1250°C, and the pressure is stabilized at -0.01 MPa. After melting for 20 minutes, the molten alloy is obtained.

[0072] Step 102. After the molten alloy prepared in step 101 is cooled to 1000°C, excess Cd powder is injected into the molten alloy. After the molten alloy is cooled to 780°C, the injection of Cd powder is stopped, and the pre-conductor is obtained.

[0073] Step 103. The pre-conductor prepared in step 102 is subjected to continuous casting, wire drawing, and annealing at 580-700℃ for 4-5 hours to obtain the conductor monomer.

[0074] (II) The preparation method of the wire core includes the following steps:

[0075] Step 201. One twist

[0076] After placing the conductor unit on the active feeder, it is stranded once under the condition that the stranding ratio is 20 times and the stranding direction is to the left. Then it is transferred to the compaction die and compacted under the condition that the compaction coefficient is 2.5mm to obtain a single stranded conductor.

[0077] Step 202. Secondary twisting

[0078] The multiple stranded conductors prepared in step 201 are transferred to a 1+6 coil stranding device. After the stranded conductors are arranged in a regular 1+6 structure, they are stranded with a stranding pitch of 120mm, a stranding direction of left and a stranding direction of right for the 1+6 structure. Then they are transferred to a pressing mold and pressed with a pressing coefficient of 6mm to obtain a secondary stranded conductor.

[0079] Step 203. Three twists

[0080] The multi-strand secondary stranded conductors prepared in step 202 are transferred to a 19-coil stranding device. The secondary stranded conductors are arranged in a regular 1+6+12 structure and then stranded in layers with a stranding pitch of 148mm. The strands are then transferred to a compaction mold and compacted with a compaction coefficient of 9.5mm to obtain the wire core.

[0081] The layered stranding process includes the following steps: stranding the wires in the left-hand direction; after the strands are stranded and compressed, stranding a 1+6 structure in the right-hand direction; after the 1+6 structure is stranded and compressed, stranding a 1+6+12 structure in the left-hand direction; and after the 1+6+12 structure is stranded and compressed, the core wire is obtained.

[0082] (III) The preparation method of the sheath material includes the following steps:

[0083] According to the composition table shown in Table 1, polyvinylidene fluoride, high-density polyethylene, calcium carbonate, graphene oxide and anhydrous ethanol are added sequentially and dispersed evenly at high speed. The raw material mixture is then fed into an extruder and extruded, cooled and granulated under the conditions of -0.01 MPa, extruder head temperature of 100℃ and extruder screw speed of 1300 rpm to obtain the sheath material.

[0084] (iv) The method for preparing flexible cables for charging piles includes the following steps:

[0085] The wire core with the outer wrapping layer is transferred to the extrusion machine. The semiconductor shielding layer material, the insulating layer material and the sheath material are put into the extrusion machine in sequence. From the inside to the outside, the semiconductor shielding layer, the insulating layer and the sheath layer are extruded on the outer periphery of the wrapping layer in sequence.

[0086] Comparative Example 1

[0087] In Example 3, the multiple stranding in the core preparation method is replaced with a single stranding. The core is obtained after one stranding, while the other conditions remain unchanged.

[0088] Comparative Example 2

[0089] The conductor monomer in Example 3 was replaced with a pure copper conductor monomer, while all other conditions remained unchanged.

[0090] Comparative Example 3

[0091] Replace the sheath material in Example 3 with commercially available polyvinyl chloride sheath material, while keeping all other conditions unchanged.

[0092] Table 1. Composition of each component in Examples 1-3 and Comparative Examples 1-3

[0093]

[0094]

[0095] The cross-sectional area obtained from Examples 1-3 and Comparative Examples 1-3 was 16 mm². 2Cables with a length of 1.5m were tested according to GB / T 4074.3-2008, in which the elongation at break in GB / T 4074.3-2008 was used as an indicator to evaluate the flexibility of the cable. The test results are shown in Table 2 below.

[0096] Table 2. Test results of cable samples from Examples 1-3 and Comparative Examples 1-3.

[0097]

[0098] As can be seen from the test results in Table 2 above, Comparative Example 1 did not perform multiple stranding of the conductor units, resulting in large gaps between conductor units, high internal stress between conductor units, and low tightness between conductors. After being made into a cable, the internal stress will greatly increase the overall hardness of the cable, increase the difficulty of bending the cable, and thus reduce the user experience.

[0099] In Comparative Example 2, the conductor monomer was made of pure copper without the use of flexible metal for modification. The single metal had poor overall performance, resulting in high overall hardness after being made into a cable, which increased the overall weight of the cable and led to a poor user experience.

[0100] In Comparative Example 3, conventional single polyvinyl chloride was selected as the sheath material. In order to introduce flexible groups, on the one hand, the overall rigidity of the cable was improved, and on the other hand, the thermal aging performance and thermal conductivity of the sheath layer were reduced, which increased the overall weight of the cable and resulted in a lower user experience.

[0101] This application provides a flexible cable for charging piles and its manufacturing method, comprising a conductor core, a sheathing layer covering the outer periphery of the conductor core, a semiconductor shielding layer covering the outer periphery of the sheathing layer, an insulation layer covering the outer periphery of the semiconductor shielding layer, and a sheathing layer covering the outer periphery of the insulation layer. The conductor core is composed of multiple conductor monomers twisted together, wherein the conductor monomers are Cu, Al, Ag, and Cd alloys. By selecting Cd alloys as the constituent elements of the conductor monomers and twisting the multiple conductor monomers multiple times, the hardness of the conductor core is reduced and the elongation at break of the conductor core is increased. By selecting a composite sheathing layer material and preparing it together with the conductor core into a cable, the tightness of each layer structure of the cable is improved while the overall hardness is reduced. This has the advantages of facilitating the routing of new energy vehicle charging piles, making it easy for users to place and retrieve cables, greatly improving the user experience, and facilitating promotion and implementation.

[0102] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A flexible cable for charging piles, characterized in that, The device includes a wire core (1), a wrapping layer (2) covering the outer periphery of the wire core (1), a semiconductor shielding layer (3) covering the outer periphery of the wrapping layer (2), an insulating layer (4) covering the outer periphery of the semiconductor shielding layer (3), and a sheath layer (5) covering the outer periphery of the insulating layer (4). The wire core (1) is formed by multiple strands of conductor monomers (6) twisted together. The conductor monomers (6) are composed of the following components by mass fraction: 85-91% Cu, 5-8% Al, 2-3% Ag and 2-3% Cd. The method for preparing the conductor monomer (6) includes the following steps: Step 101. Cu, Al and Ag are added to a vacuum melting furnace in the mass ratio. The furnace is heated from room temperature to 1150-1250℃ and stabilized at -0.01 MPa. After melting for 20-30 minutes, the molten alloy is obtained. Step 102. After the molten alloy prepared in step 101 is cooled to 950-1000℃, excess Cd powder is sprayed into the molten alloy. After the molten alloy is cooled to 600-780℃, the spraying of Cd powder is stopped, and the pre-conductor is obtained. Step 103. After the pre-conductor prepared in step 102 is subjected to continuous casting and wire drawing annealing, the conductor monomer is obtained. The method for preparing the wire core includes the following steps: Step 201. One twist After placing the conductor unit on the active feeder, it is stranded once under the condition that the stranding ratio is 20 times and the stranding direction is to the left. Then it is transferred to the pressing die and pressed under the condition that the pressing coefficient is 2-2.5mm to obtain a single stranded conductor. Step 202. Secondary twisting The multiple primary stranded conductors prepared in step 201 are transferred to a 1+6 coil stranding device. After the primary stranded conductors are arranged in a regular 1+6 structure, they are stranded with a stranding pitch of 100-120mm, a stranding direction of left, and a stranding direction of right for the 1+6 structure. After stranding, they are transferred to a pressing mold and pressed with a pressing coefficient of 5.5-6mm to obtain a secondary stranded conductor. Step 203. Three twists The multi-strand secondary stranded conductors prepared in step 202 are transferred to a 19-coil stranding device. The secondary stranded conductors are arranged in a regular 1+6+12 structure and stranded in layers with a stranding pitch of 128-148mm. They are then transferred to a compaction mold and compacted with a compaction coefficient of 8.5-9.5mm to obtain the wire core.

2. The flexible cable for charging piles according to claim 1, characterized in that, The annealing temperature in step 103 is 580-700℃.

3. The flexible cable for a charging pile according to claim 1, characterized in that, Step 203, layered stranding, includes the following steps: stranding the wires in the left-hand direction; after the strands are stranded and pressed tightly, stranding a 1+6 structure in the right-hand direction; after the 1+6 structure is stranded and pressed tightly, stranding a 1+6+12 structure in the left-hand direction; after the 1+6+12 structure is stranded and pressed tightly, the wire core is obtained.

4. The flexible cable for a charging pile according to claim 1, characterized in that, The material of the wrapping layer (2) is bulletproof wire, and the weaving density of the wrapping layer (2) is 95%-97%.

5. A flexible cable for a charging pile according to claim 1, characterized in that, By weight, the sheath layer (5) is composed of the following components: 30-45 parts polyvinylidene fluoride, 8-12 parts high-density polyethylene, 5-8 parts calcium carbonate, 2-5 parts graphene oxide, and 1-5 parts anhydrous ethanol.

6. A flexible cable for a charging pile according to claim 5, characterized in that, The preparation method of the raw material of the sheath layer (5) includes the following steps: polyvinylidene fluoride, high-density polyethylene, calcium carbonate, graphene oxide and anhydrous ethanol are added in sequence and dispersed evenly at high speed. The raw material mixture is then transported to an extruder and extruded, cooled and granulated under the conditions of -0.01 MPa, extruder head temperature of 90-100℃ and extruder screw speed of 1300 rpm to obtain the sheath material.

7. The method for preparing a flexible cable for a charging pile according to claim 1, characterized in that, Includes the following steps: The wire core with the outer wrapping layer is transferred to the extrusion machine. The semiconductor shielding layer material, the insulating layer material and the sheath material are put into the extrusion machine in sequence. From the inside to the outside, the semiconductor shielding layer, the insulating layer and the sheath layer are extruded on the outer periphery of the wrapping layer in sequence.

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