Lightweight liquid cooling cable for direct current charging pile and production process thereof

Abstract

The invention discloses a light-weight liquid cooling cable for a direct current charging pile and a production process of the light-weight liquid cooling cable. The light-weight liquid cooling cable for the direct current charging pile comprises a cable core, a filling layer, a belting layer and a sheath layer, a belting layer and a sheath layer are sequentially wrapped outside the cable core, and a filling layer is filled between the belting layer and the cable core; the filling layer is made of a PP rope material, the belting layer is made of a non-woven fabric material, and the sheath layer is made of a thermoplastic elastomer material. The production process sequentially comprises the steps of extrusion of the double-crescent skeleton, stranding of the main power core wire conductor, extrusion of the main power core wire, extrusion of the grounding core wire, extrusion of the auxiliary power core wire, extrusion of the control core wire group and the communication core wire group, overall stranding of the cable core and extrusion of the outer sheath. Through the structural design and material combination, the cable has good mechanical strength and anti-aging performance, meanwhile, the temperature of the cable can be effectively controlled under the high-power charging condition, and therefore the overall safety of the charging pile is improved, and the service life of the charging pile is prolonged.

Description

Technical Field

[0001] The present invention belongs to the field of safety cables and production processes, and specifically relates to a liquid-cooled cable for a lightweight DC charging pile and a production process thereof. Background Art

[0002] With the rapid growth of the electric vehicle market, the demand for efficient and fast charging is also increasing, such as ultra-high-speed charging stations in highways, urban charging hubs, commercial fleets such as electric buses, trucks, taxis, and charging of industrial electric equipment such as electric forklifts and large machinery. Existing direct current (DC) charging technology can provide high charging power, but with the continuous increase in battery capacity and power demand of electric vehicles, the charging power in the future may reach hundreds of kilowatts or even higher. Traditional charging cables face a significant increase in cable heating at high power, which not only causes energy loss, but may also cause safety hazards due to overheating. In order to transmit higher power, traditional cables often need to increase the cross-sectional area of ​​the wire, which makes the cable thicker and heavier, and the flexibility of use is greatly reduced, especially in large-scale public charging stations or home charging scenarios, the user experience is poor.

[0003] The DC liquid-cooled cable actively removes the heat generated by high current transmission by adding a coolant circulation system inside the cable, thereby greatly improving the current carrying capacity of the cable. This design enables the liquid-cooled cable to safely and efficiently transmit large currents in a smaller cross-sectional area. Compared with conventional cables, it can better control the temperature at the same power and reduce the risk of cable overheating. Taking the DC charging cable with a designed charging power of 100kW and a maximum allowable current of 250A as an example, a good liquid-cooled cable and liquid cooling system design can reduce the cross-sectional area of ​​the main cable by 30-70%, and the total weight of the cable can be reduced to a minimum of 1.7kg / meter. The design of the liquid-cooled cable makes it lighter and smaller, making it easier and more convenient for users to operate the charging gun, and less likely to feel tired. It also avoids the discomfort caused by high-temperature cables, significantly improving the user experience when plugging and unplugging the charging gun.

[0004] In the prior art, liquid-cooled cables for DC charging piles usually adopt a separate liquid cooling pipeline solution and a conductor immersion liquid cooling solution. In the separate liquid cooling pipeline solution, the coolant flows through an independent pipeline separated from the conductor, which makes the system design more flexible, simple to maintain and highly reliable, because there is a clear isolation between the coolant and the conductor, reducing the impact of liquid leakage or corrosion on the electrical performance of the cable. However, the cooling efficiency of this solution is relatively low, because the heat transfer efficiency between the coolant and the conductor is not as high as direct contact (such as immersion), and the independent pipeline design takes up more space, which may increase the size and weight of the cable. In contrast, in the conductor immersion solution, the conductor is directly immersed in the coolant, providing extremely high cooling efficiency, because the coolant can directly contact the conductor and quickly take away the heat, so that the cable size can be smaller and lighter, suitable for high-power, high-heat-density application scenarios. However, this design also brings higher system complexity, and it is necessary to ensure the compatibility of the coolant with the conductor and the insulating material to avoid corrosion and leakage. At the same time, it is also necessary to design sufficient and stable liquid cooling channels in the conductor structure so that the coolant can circulate smoothly during the period to take away the heat. Summary of the invention

[0005] The present invention provides a liquid-cooled cable for a lightweight DC charging pile and a production process thereof. The cable is particularly suitable for an immersion liquid cooling solution and is intended to solve the problems of aging, corrosion and high production cost that are prone to occur in existing liquid-cooled cables during long-term use.

[0006] This invention not only utilizes the excellent corrosion resistance of polyperfluoroethylene propylene fluoroplastics to avoid the problems caused by the contact between coolant and conventional thermoplastic insulation materials, but also uses thermoplastic elastomer materials on the outer layer to reduce production costs while maintaining flexibility, thus avoiding the problems of cable stiffness and high cost caused by perfluoroplastic insulation. Through this structural design and material combination, the cable not only has good mechanical strength and anti-aging properties, but can also effectively control the temperature of the cable under high-power charging conditions, thereby improving the overall safety and service life of the charging pile.

[0007] The technical solution adopted by the present invention includes:

[0008] 1. A lightweight liquid-cooled cable for DC charging piles

[0009] It includes a cable core, a filling layer, a tape layer and a sheath layer; the cable core is wrapped with the tape layer and the sheath layer in sequence, and the filling layer is filled between the tape layer and the cable core; the filling layer is made of PP rope material, the tape layer is made of non-woven fabric material, and the sheath layer is made of thermoplastic elastomer material.

[0010] The cable core includes two main power core wires with a special double-crescent support structure, a grounding core wire, two auxiliary power core wires, a control core wire group and two groups of communication core wire groups; the two main power core wires, the grounding core wire, the two auxiliary power core wires, the control core wire group and the two groups of communication core wire groups are twisted together, and the twisted gaps are filled with a filling layer.

[0011] The main power core wire comprises a double crescent frame, a plurality of main power core wire conductors, a main power core wire sheathing insulation layer and a main power core wire main insulation layer; the plurality of main power core wire conductors are twisted on the outer periphery of the double crescent frame, the main power core wire conductors after twisting are sheathed with the main power core wire sheathing insulation layer, the main power core wire sheathing insulation layer seals the twisted main power core wire conductors, and the main power core wire sheathing insulation layer is wrapped with the main power core wire main insulation layer.

[0012] The grounding core wire includes a grounding core wire conductor and a grounding core wire insulation layer; the grounding core wire conductor is wrapped with a grounding core wire insulation layer; the auxiliary power core wire includes an auxiliary power core wire conductor and an auxiliary power core wire insulation layer; the auxiliary power core wire conductor is wrapped with an auxiliary power core wire insulation layer.

[0013] The control core wire group includes a plurality of control core wire conductors, a plurality of control core wire insulation layers, a control core wire aluminum foil shielding layer, a control core wire braided shielding layer and a control core wire inner sheath layer; each of the control core wire conductors is wrapped with a control core wire insulation layer to form a plurality of control core wires, and the plurality of control core wires are twisted together, and the twisted control core wires are sequentially wrapped with a control core wire aluminum foil shielding layer, a control core wire braided shielding layer and a control core wire inner sheath layer.

[0014] The communication core wire group includes a plurality of communication core wire conductors, a plurality of communication core wire insulation layers, a communication core wire aluminum foil shielding layer, a communication core wire braided shielding layer and a communication core wire inner sheath layer; each of the communication core wire conductors is wrapped with a communication core wire insulation layer to form a plurality of communication core wires, and the plurality of communication core wires are twisted together, and the twisted gaps are filled with cotton yarns, and the twisted communication core wires are sequentially wrapped with a communication core wire aluminum foil shielding layer, a communication core wire braided shielding layer and a communication core wire inner sheath layer.

[0015] The material of the double crescent frame is poly(perfluoroethylene propylene) fluoroplastic;

[0016] The cross-section of the double-crescent skeleton is designed to be a double-crescent shape, and the double-crescent shape has a semicircular groove on each side along the circular diameter, so that the double-crescent skeleton body is used to support the twisted form of the external conductor. The double-crescent grooves of the double-crescent skeleton design are used to circulate coolant to perform liquid cooling on the main power core wire conductor when used in conjunction with a charging pile.

[0017] The materials of the main insulation layer of the main power core wire, the insulation layer of the grounding core wire, the insulation layer of the auxiliary power core wire, the insulation layer of the control core wire and the insulation layer of the communication core wire are all thermoplastic elastomers.

[0018] 2. A production process for a liquid-cooled cable for a lightweight DC charging pile, comprising the following steps:

[0019] S1, double crescent frame extrusion:

[0020] Use an extruder to process the polyperfluoroethylene propylene fluoroplastic and extrude a double crescent skeleton.

[0021] S2. Main power core conductor twisting:

[0022] Copper wire is used as the main power core wire sub-conductor, and several main power core wire sub-conductors are evenly divided into N groups. The N groups of main power core wire sub-conductors are twisted separately to form N groups of main power core wire conductors, and then the N groups of main power core wire conductors are evenly dispersed and arranged and twisted on the periphery of the double crescent frame.

[0023] S3, main power core wire extrusion:

[0024] The main power core wire is formed by wrapping the main power core wire insulation layer around the outer periphery of the twisted main power core wire conductor, and then wrapping the main power core wire main insulation layer around the outer periphery of the main power core wire insulation layer.

[0025] S4, grounding core wire extrusion:

[0026] Thermoplastic elastomer is used as the ground core wire insulation layer, so that the ground core wire insulation layer is tightly pressed on the outer periphery of the ground core wire conductor to form the ground core wire.

[0027] S5, auxiliary power core wire extrusion:

[0028] A thermoplastic elastomer is used as the auxiliary power core wire insulation layer, so that the auxiliary power core wire insulation layer is tightly squeezed on the outer periphery of the auxiliary power core wire conductor to form the auxiliary power core wire.

[0029] S6, control core wire assembly and communication core wire assembly extrusion:

[0030] Insulating layers are tightly squeezed around the periphery of the control core conductor and the communication core conductor to form the control core wire and the communication core wire; a number of control core wires are directly twisted, and then the periphery after twisting is wrapped with an aluminum foil shielding layer and a metal braided mesh in turn, and then an outer sheath is pressed out from the periphery of the metal braided mesh; a number of communication core wires are directly twisted, and then the periphery after twisting is wrapped with an aluminum foil shielding layer and a metal braided mesh in turn, and then an outer sheath is pressed out from the periphery of the metal braided mesh.

[0031] S7, cable core overall twisting:

[0032] Two main power core wires, a grounding core wire, two auxiliary power core wires, a control core wire group and two communication core wire groups are twisted together as a whole. The gaps between the twists are filled with PP rope as a filling layer. After the twisting is completed, non-woven fabric is used as a wrapping layer for wrapping.

[0033] S8, outer sheath extrusion:

[0034] A thermoplastic elastomer is used as the sheath layer, so that the sheath layer is tightly squeezed on the outer periphery of the tape layer to form a lightweight liquid-cooled cable for a DC charging pile.

[0035] After the cable is formed, when the liquid-cooled cable for lightweight DC charging pile is used in conjunction with the charging pile, the coolant is filled into the liquid-cooled cable for lightweight DC charging pile through the charging pile, and the coolant flows into the double crescent groove and the gap after several main power core wire conductors are twisted together, and directly contacts the main power core wire conductors to achieve liquid cooling.

[0036] In step S1:

[0037] The double crescent skeleton extruder adopts a single screw extruder with a screw length to diameter ratio of 25:1. The screw is designed as a gradual compression type. The feed section temperature is 240°C-260°C, the compression section temperature is 270°C-290°C, the neck section temperature is 280°C-300°C, the mold section temperature is 290°C-310°C, the screw speed is 10-20RPM, and the screw linear speed is 0.5-1.0m / min.

[0038] The cross-section of the double-crescent skeleton is designed to be a double-crescent shape, and the double-crescent shape has a semicircular groove on each side along the circular diameter. The semicircular groove is used to circulate coolant to perform liquid cooling on the main power core conductor when used in conjunction with a charging pile.

[0039] The step S3 is specifically as follows:

[0040] Polyperfluoroethylene propylene fluoroplastic is used as the insulating layer of the main power core wire, so that the outer periphery of the main power core wire conductor after the main power core wire insulating layer is twisted, and the thermoplastic elastomer material is used as the main insulating layer of the main power core wire. The main power core wire insulating layer extrusion host and the main power core wire main insulating layer extrusion host are arranged in parallel. When the polyperfluoroethylene propylene fluoroplastic is still in a high-temperature molten soft state, the thermoplastic elastomer material is immediately extruded through the main power core wire main insulating layer extrusion host. The thermoplastic elastomer material is coated on the outer periphery of the polyperfluoroethylene propylene fluoroplastic fused to the main insulating layer of the main power core wire in a high-temperature molten state, thereby ensuring that the polyperfluoroethylene propylene fluoroplastic of the main power core wire insulating layer and the polyperfluoroethylene propylene fluoroplastic of the main insulating layer of the main power core wire are integrated to form the final main power core wire.

[0041] In step S3:

[0042] The main power core wire insulation layer extrusion machine uses a high-temperature extruder, the feed section temperature is 220°C-250°C, the compression section temperature is 250°C-280°C, the neck section temperature is 280°C-300°C, the mold section temperature is 300°C-350°C, the screw speed is 20-40RPM, and the cooling water tank temperature is 30-40°C;

[0043] The main extruder for the main insulation layer of the main power core wire adopts a high-temperature extruder, with a feed section temperature of 160°C-180°C, a compression section temperature of 180°C-200°C, a neck section temperature of 200°C-220°C, a mold section temperature of 190°C-220°C, a screw speed of 30-50RPM, and a cooling water tank temperature of 20-30°C.

[0044] The step S6 is specifically as follows:

[0045] Control core wire group extrusion: Thermoplastic elastomer is used as the control core wire insulation layer, so that the control core wire insulation layer is tightly squeezed on the periphery of the control core wire conductor to form a control core wire, and several control core wires are directly twisted. After twisting, the outer layer is wrapped with aluminum foil Mylar to form an aluminum foil shielding layer of the control core wire, and a metal braided mesh is added to the periphery of the aluminum foil shielding layer of the control core wire to form a braided shielding layer of the control core wire. Thermoplastic elastomer is used as the inner sheath layer of the control core wire, so that the inner sheath layer of the control core wire is tightly squeezed on the periphery of the braided shielding layer of the control core wire to form a control core wire group.

[0046] Communication core wire group extrusion: Thermoplastic elastomer is used as the communication core wire insulation layer, so that the communication core wire insulation layer is tightly squeezed on the outer periphery of the communication core wire conductor to form a communication core wire, and several communication core wires are directly twisted. Cotton yarn is used for filling during twisting. After twisting, the outer layer is wrapped with aluminum foil Mylar to form an aluminum foil shielding layer of the communication core wire. A metal braided mesh is added to the outer periphery of the aluminum foil shielding layer of the communication core wire to form a braided shielding layer of the communication core wire. Thermoplastic elastomer is used as the inner sheath layer of the communication core wire, and the inner sheath layer of the communication core wire is extruded from the outer periphery of the braided shielding layer of the communication core wire to form a communication core wire group.

[0047] In step S8:

[0048] The extruder of the outer sheath adopts a single screw extruder with a screw diameter of 120 mm, a screw aspect ratio of 25:1, a feed section temperature of 170°C-190°C, a compression section temperature of 180°C-200°C, a machine neck section temperature of 190°C-210°C, a mold section temperature of 200°C-220°C, a screw speed of 30-45RPM, and a screw linear speed of 8-12m / min.

[0049] The innovation of the present invention lies in the use of two main power core wires with a special double-crescent support structure. When used in conjunction with a charging pile, the coolant flows through the double-crescent skeleton into the gaps after the main power core wire conductors are twisted, thereby liquid-cooling the main power core wire conductors. This immersion coolant solution achieves higher cooling efficiency.

[0050] The innovation of the present invention is that the inner layer uses polyperfluoroethylene propylene fluoroplastic as the insulation layer of the main power core wire to avoid the problems caused by the contact between the coolant and the conventional thermoplastic insulation material, and the outer layer uses thermoplastic elastomer material as the main insulation layer of the main power core wire, so that the cable can maintain flexibility while reducing the production cost, avoiding the problems of cable stiffness and high cost caused by perfluoroplastic insulation. With this structural design and material combination, the cable not only has good mechanical strength and anti-aging performance, but also can effectively control the temperature of the cable under high-power charging conditions, thereby improving the overall safety and service life of the charging pile.

[0051] The beneficial effects of the present invention are:

[0052] 1. The present invention adopts polyperfluoroethylene propylene fluoroplastic to make a double-crescent frame, which provides support when the conductor is twisted, forming a sufficient and stable space as a liquid cooling channel for the flow of coolant. The coolant flows through the double-crescent frame to the gap after the conductor is twisted, and the conductor is liquid-cooled during charging, thereby achieving higher cooling efficiency.

[0053] 2. The inner layer of the main power core wire of the present invention adopts polyperfluoroethylene propylene fluoroplastic as the main power core wire covering insulation layer, which isolates the conductor and coolant from external cable materials and structures, forming a reliable closed space to effectively prevent the coolant from directly contacting with external structures and materials, and avoid material aging and corrosion caused by long-term contact.

[0054] 3. The outer layer of the main power core wire of the present invention adopts thermoplastic elastomer material as the main insulation layer of the main power core wire, so that the cable can maintain flexibility while reducing production costs, avoiding the problems of cable rigidity and high cost caused by perfluoroplastic insulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a cross-sectional view of the cable of the present invention.

[0056] In the figure: 1. Main power core wire; 2. Grounding core wire; 3. Auxiliary power core wire; 4. Control core wire group; 5. Communication core wire group; 6. Filling layer; 7. Tape layer; 8. Sheath layer; 1-1. Double crescent skeleton; 1-2. Main power core wire conductor; 1-3. Main power core wire insulation layer; 1-4. Main power core wire main insulation layer; 2-1. Grounding core wire conductor; 2-2. Grounding core wire insulation layer; 3-1. Auxiliary power core wire Line conductor; 3-2, auxiliary power core wire insulation layer; 4-1, control core wire conductor; 4-2, control core wire insulation layer; 4-3, control core wire aluminum foil shielding layer; 4-4, control core wire braided shielding layer; 4-5, control core wire inner sheath layer; 5-1, communication core wire conductor; 5-2, communication core wire insulation layer; 5-3, communication core wire aluminum foil shielding layer; 5-4, communication core wire braided shielding layer; 5-5, communication core wire inner sheath layer. DETAILED DESCRIPTION

[0057] The present invention is described in more detail below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited thereto. For those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention. The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in the field.

[0058] The lightweight liquid-cooled cable for a DC charging pile of the present invention comprises:

[0059] Cable core, filling layer 6, tape layer 7 and sheath layer 8; the cable core is wrapped with tape layer 7 and sheath layer 8 in sequence, and the filling layer 6 is filled between the tape layer 7 and the cable core; the filling layer 6 is made of PP rope material, the tape layer 7 is made of non-woven fabric material, and the sheath layer 8 is made of thermoplastic elastomer material.

[0060] The cable core includes two main power core wires 1 with a special double-crescent support structure, a grounding core wire 2, two auxiliary power core wires 3, a control core wire group 4 and two groups of communication core wire groups 5; the two main power core wires 1, the grounding core wire 2, the two auxiliary power core wires 3, the control core wire group 4 and the two groups of communication core wire groups 5 are twisted together, and the twisted gaps are filled with a filling layer 6, and the cable core and the filling layer 6 formed by twisting are wrapped with a tape layer 7.

[0061] The main power core wire 1 comprises a double crescent frame 1-1, a plurality of main power core wire conductors 1-2, a main power core wire insulation layer 1-3 and a main power core wire main insulation layer 1-4; the plurality of main power core wire conductors 1-2 are twisted on the outer periphery of the double crescent frame 1-1, the main power core wire conductors 1-2 after twisting are covered with the main power core wire insulation layer 1-3, the main power core wire insulation layer 1-3 seals the twisted main power core wire conductors 1-2, and the main power core wire insulation layer 1-3 is wrapped with the main power core wire main insulation layer 1-4;

[0062] The grounding core wire 2 comprises a grounding core wire conductor 2-1 and a grounding core wire insulation layer 2-2; the grounding core wire conductor 2-1 is wrapped with the grounding core wire insulation layer 2-2.

[0063] The auxiliary power core wire 3 comprises an auxiliary power core wire conductor 3-1 and an auxiliary power core wire insulation layer 3-2; the auxiliary power core wire conductor 3-1 is wrapped with the auxiliary power core wire insulation layer 3-2.

[0064] The control core wire group 4 includes a plurality of control core wire conductors 4-1, a plurality of control core wire insulation layers 4-2, a control core wire aluminum foil shielding layer 4-3, a control core wire braided shielding layer 4-4 and a control core wire inner sheath layer 4-5; each control core wire conductor 4-1 is wrapped with a control core wire insulation layer 4-2 to form a plurality of control core wires, and the plurality of control core wires are twisted together, and the twisted control core wires are sequentially wrapped with a control core wire aluminum foil shielding layer 4-3, a control core wire braided shielding layer 4-4 and a control core wire inner sheath layer 4-5.

[0065] The communication core wire group 5 includes a plurality of communication core wire conductors 5-1, a plurality of communication core wire insulation layers 5-2, a communication core wire aluminum foil shielding layer 5-3, a communication core wire braided shielding layer 5-4 and a communication core wire inner sheath layer 5-5; each communication core wire conductor 5-1 is wrapped with a communication core wire insulation layer 5-2 to form a plurality of communication core wires, and the plurality of communication core wires are twisted together, and the twisted gaps are filled with cotton yarns, and the twisted communication core wires are sequentially wrapped with a communication core wire aluminum foil shielding layer 5-3, a communication core wire braided shielding layer 5-4 and a communication core wire inner sheath layer 5-5.

[0066] The material of the double-crescent skeleton 1-1 is polytetrafluoroethylene propylene fluoroplastic; the cross-section of the double-crescent skeleton 1-1 is designed to be a double-crescent shape, and the double-crescent shape has a semicircular groove on each side symmetrically along the circular diameter, so that the main body of the double-crescent skeleton 1-1 is used to support the twisted form of the external conductor, and the double-crescent grooves designed in the double-crescent skeleton 1-1 are used to circulate coolant to cool the main power core conductor 1-2 when used in conjunction with the charging pile; the materials of the main insulation layer 1-4 of the main power core, the grounding core insulation layer 2-2, the auxiliary power core insulation layer 3-2, the control core insulation layer 4-2 and the communication core insulation layer 5-2 are all thermoplastic elastomers.

[0067] When the liquid-cooled cable for a lightweight DC charging pile is used in conjunction with the charging pile, the coolant is charged into the liquid-cooled cable for a lightweight DC charging pile through the charging pile, and the coolant flows into the double crescent groove and the gap between several main power core conductors 1-2 twisted together, and directly contacts the main power core conductors 1-2, thereby achieving liquid cooling.

[0068] The production process of the lightweight liquid-cooled cable for a DC charging pile of the present invention comprises the following steps:

[0069] S1, double crescent frame 1-1 extrusion:

[0070] The polyperfluoroethylene propylene fluoroplastic is processed by using an extruder to extrude a double crescent skeleton 1-1.

[0071] In step S1: the extruder of the double crescent skeleton 1-1 adopts a single screw extruder, the screw length and diameter ratio is 25:1, the screw is designed as a gradual compression type to ensure uniform plasticization and extrusion of the material, the feed section temperature is 240℃-260℃, the compression section temperature is 270℃-290℃, the machine neck section temperature is 280℃-300℃, the mold section temperature is 290℃-310℃, the screw speed is 10-20RPM, the screw linear speed is 0.5-1.0m / min, avoid excessive shearing due to excessive speed, and ensure that the fluoroplastic melt flows smoothly in the mold without cold spots. The cross-section of the double crescent skeleton 1-1 is designed as a double crescent shape, and the double crescent shape has a semicircular groove on each side symmetrically along the circular diameter.

[0072] In this embodiment, the area of ​​the semicircular groove is approximately 3 / 4 of the area of ​​a circle with a diameter of 2 mm. The diameter of the maximum physical size of the double-crescent skeleton 1-1 is approximately 3.4 mm. The main body of the double-crescent skeleton 1-1 is used to support the twisted form of the external conductor. The double-crescent groove designed in the double-crescent skeleton 1-1 is used to circulate the coolant. The internal flow channel of the extrusion mold is designed to be tapered to ensure that the molten fluoroplastic can be evenly distributed to various parts of the mold. The design of the flow channel needs to avoid forming dead corners in the crescent-shaped area to prevent material retention. The first section of the water tank in the demolding area uses compressor circulating cooling water for efficient cooling.

[0073] S2, main power core conductor 1-2 twisted:

[0074] Copper wire is used as the main power core wire sub-conductor, and several main power core wire sub-conductors are evenly divided into N groups. The N groups of main power core wire sub-conductors are twisted by using a pair twisting machine to form N groups of main power core wire conductors 1-2. Then, the N groups of main power core wire conductors 1-2 are evenly dispersed and arranged and twisted on the periphery of the double crescent skeleton 1-1 by using a cage twisting machine.

[0075] In this embodiment, a 0.3 mm thin copper conductor conforming to the IEC60228 Class 5 standard is used as the main power core conductor 1-2, and the overall cross-sectional area of ​​the main power core conductor 1-2 is 35 mm 2 The total number of main power core conductors 1-2 is 498, which are divided into 6 groups, each group contains 83 conductors, the two twisting directions are S direction, the re-twisting process is 100% back-twisting treatment, and the re-twisting pitch ratio is 18-24.

[0076] The entire process reduces the internal stress generated during twisting, thereby avoiding excessive extrusion of the conductor on the frame during twisting. The double-crescent frame can maintain good shape stability during the twisting process, ensuring the smooth shape of the liquid cooling channel space.

[0077] S3, main power core line 1 extrusion:

[0078] The main power core wire 1 is formed by wrapping the main power core wire insulating layer 1-3 around the outer periphery of the twisted main power core wire conductor 1-2, and then wrapping the main power core wire main insulating layer 1-4 around the outer periphery of the main power core wire insulating layer 1-3.

[0079] Step S3 specifically comprises: using polyperfluoroethylene propylene fluoroplastic as the main power core wire coating insulation layer 1-3, so that the outer periphery of the main power core wire conductor 1-2 after the main power core wire coating insulation layer 1-3 is twisted, using thermoplastic elastomer material as the main power core wire main insulation layer 1-4, the main power core wire coating insulation layer 1-3 extrusion host and the main power core wire main insulation layer 1-4 extrusion host are arranged in parallel, when the polyperfluoroethylene propylene fluoroplastic is still in a high-temperature molten soft state, the thermoplastic elastomer material is immediately extruded through the main power core wire main insulation layer 1-4 extrusion host, and the thermoplastic elastomer material is coated and fused to the outer periphery of the polyperfluoroethylene propylene fluoroplastic of the main power core wire main insulation layer 1-4 in a high-temperature molten state, thereby ensuring that the polyperfluoroethylene propylene fluoroplastic of the main power core wire coating insulation layer 1-3 and the polyperfluoroethylene propylene fluoroplastic of the main power core wire main insulation layer 1-4 are integrated to form the final main power core wire 1.

[0080] In this embodiment, the thickness of the FEP fluoroplastic is controlled at about 0.35 mm, and the thickness of the thermoplastic elastomer is controlled at about 1.1 mm.

[0081] The main power core wire insulation layer 1-3 extrusion host only performs preliminary shaping of the material surface size and structure, and then immediately uses pipeline air pressure to blow wet the cable surface to remove moisture. When the polytetrafluoroethylene propylene fluoroplastic is still in a high-temperature soft state after preliminary cooling and blowing, the main power core wire main insulation layer 1-4 is immediately extruded. The thermoplastic elastomer is extruded at a high temperature and directly fused with the polytetrafluoroethylene propylene fluoroplastic which is still in a high-temperature soft state.

[0082] Since the surfaces of the two materials still have high heat, sufficient interface adhesion can be achieved, ensuring the close bonding of the coating insulation layer and the main insulation layer. The entire process requires precise control of the speed, pressure and temperature of the extruder to ensure the uniformity and adhesion of the material extrusion, thereby forming a double-layer insulation with excellent adhesion and structural stability.

[0083] In step S3: the extruder of the main power core wire coating insulation layer 1-3 uses a high-temperature extruder, the feed section temperature is 220°C-250°C, the compression section temperature is 250°C-280°C, the machine neck section temperature is 280°C-300°C, the mold section temperature is 300°C-350°C, the screw speed is 20-40RPM, and the cooling water tank temperature is 30-40°C; the extruder of the main insulation layer 1-4 of the main power core wire uses a high-temperature extruder, the feed section temperature is 160°C-180°C, the compression section temperature is 180°C-200°C, the machine neck section temperature is 200°C-220°C, the mold section temperature is 190°C-220°C, the screw speed is 30-50RPM, and the cooling water tank temperature is 20-30°C.

[0084] S4, ground core wire 2 is extruded:

[0085] A 90°C grade thermoplastic elastomer conforming to GB / T 33594 standard is used as the grounding core wire insulation layer 2 - 2 , so that the grounding core wire insulation layer 2 - 2 is tightly squeezed on the outer periphery of the grounding core wire conductor 2 - 1 to form the grounding core wire 2 .

[0086] In this embodiment, the cross-sectional area of ​​the ground core conductor 2-1 is 25 mm 2 , a 0.2mm thin copper conductor that complies with the IEC60228Class6 standard is used as the grounding core conductor 2-1.

[0087] S5, auxiliary power core wire 3 extrusion:

[0088] A 90°C grade thermoplastic elastomer conforming to GB / T 33594 standard is used as the auxiliary power core wire insulation layer 3 - 2 , so that the auxiliary power core wire insulation layer 3 - 2 is tightly squeezed on the outer periphery of the auxiliary power core wire conductor 3 - 1 to form the auxiliary power core wire 3 .

[0089] In this embodiment, the cross-sectional area of ​​the auxiliary power core conductor 3-1 is 2.5 mm 2 , a 0.15mm fine copper conductor that complies with the IEC60228 Class 6 standard is used as the auxiliary power core conductor 3-1. During the process of twisting the fine copper conductor to form the auxiliary power core conductor 3-1, Kevlars fiber is added inside for tensile reinforcement to avoid breakage during frequent pulling dynamic applications.

[0090] S6, control core wire group 4 and communication core wire group 5 are pushed out:

[0091] Insulating layers are tightly squeezed around the periphery of the control core conductor 4-1 and the communication core conductor 5-1 to form a control core wire and a communication core wire; a number of control core wires are directly twisted together, and then an aluminum foil shielding layer and a metal braided mesh are wrapped around the twisted periphery in sequence, and then an outer sheath is extruded around the metal braided mesh; a number of communication core wires are directly twisted together, and then an aluminum foil shielding layer and a metal braided mesh are wrapped around the twisted periphery in sequence, and then an outer sheath is extruded around the metal braided mesh.

[0092] Step S6 is specifically as follows: extrusion of the control core wire group 4: using a 90°C grade thermoplastic elastomer that complies with the GB / T 33594 standard as the control core wire insulation layer 4-2, so that the control core wire insulation layer 4-2 is tightly squeezed on the periphery of the control core wire conductor 4-1 to form a control core wire, directly twisting a number of control core wires, and after twisting, the outer layer is wrapped with aluminum foil Mylar in a wrapping manner to form a control core wire aluminum foil shielding layer 4-3, and a metal braided mesh is added to the periphery of the control core wire aluminum foil shielding layer 4-3 to form a control core wire braided shielding layer 4-4 to further enhance the anti-interference ability in low-frequency and high-current application environments, and using a 90°C grade thermoplastic elastomer that complies with the GB / T33594 standard as the control core wire inner sheath layer 4-5, so that the control core wire inner sheath layer 4-5 is tightly squeezed on the periphery of the control core wire braided shielding layer 4-4 to form a control core wire group 4.

[0093] In this embodiment, the control core wire is directly twisted into 8 cores, and the cross-sectional area of ​​the control core wire conductor 4-1 is 1.0mm 2 , a 0.15mm fine-filament copper conductor that complies with the IEC 60228 Class 6 standard is used as the control core conductor 4-1. During the process of twisting the fine-filament copper conductor to form the control core conductor 4-1, Kevlars fiber is added inside to strengthen the tensile strength to avoid breakage during frequent pulling and dynamic applications.

[0094] Extrusion of the communication core wire group 5: A thermoplastic elastomer with a grade of 90°C that meets the GB / T 33594 standard is used as the communication core wire insulation layer 5-2, so that the communication core wire insulation layer 5-2 is tightly squeezed on the outer periphery of the communication core wire conductor 5-1 to form a communication core wire, and a number of communication core wires are directly twisted. When twisting, cotton yarn is used for tight filling to increase tensile strength. After twisting, the outer layer is wrapped with aluminum foil Mylar to form a communication core wire aluminum foil shielding layer 5-3, and a metal braided mesh is added to the outer periphery of the communication core wire aluminum foil shielding layer 5-3 to form a communication core wire braided shielding layer 5-4 to further enhance the anti-interference ability in low-frequency and high-current application environments. A thermoplastic elastomer with a grade of 90°C that meets the GB / T 33594 standard is used as the communication core wire inner sheath layer 5-5, and the communication core wire inner sheath layer 5-5 is extruded from the outer periphery of the communication core wire braided shielding layer 5-4 to form the communication core wire group 5.

[0095] In this embodiment, the communication core wire adopts two cores directly twisted together to form a communication core wire group 5. There are two communication core wire groups 5 for transmitting differential signals. The cross-sectional area of ​​the core wire conductor 5-1 is 1.0 mm. 2 , a 0.15mm fine copper conductor that complies with the IEC60228 Class 6 standard is used as the communication core conductor 5-1. During the process of twisting the fine copper conductor to form the communication core conductor 5-1, Kevlars fiber is added inside to strengthen the tensile strength to avoid breakage during frequent pulling and dynamic applications.

[0096] S7, cable core overall twisting:

[0097] Two main power core wires 1, a grounding core wire 2, two auxiliary power core wires 3, a control core wire group 4 and two communication core wire groups 5 are twisted together as a whole, and the gaps between the twisted wires are filled with PP rope as a filling layer 6. After the twisting is completed, non-woven fabric is used as a wrapping layer 7 for wrapping.

[0098] The cage stranding machine is used as the stranding equipment. During the stranding process, each core wire and the combined unit are fed separately through multiple stations of the cage stranding machine and introduced into the stranding area. In order to ensure that no additional stress is generated on the core wire during the stranding process, all core wires need to be 100% untwisted during stranding, so that each core wire and the combined unit can rotate in the opposite direction while being stranded, avoiding twisting and deformation during the stranding process, and ensuring the stability of the physical and electrical properties of the core wire after stranding. During the stranding process, the pitch ratio is an important control parameter, which is usually set between 16 and 24 times, that is, the stranding pitch is 16 to 24 times the outer diameter of the cable. The specific ratio is fine-tuned according to the cable diameter and design requirements to ensure that the cable has good mechanical strength while maintaining sufficient flexibility. During the stranding process, the PP rope can effectively fill all gaps, ensure that the cross-section of the cable is round after the cable is formed, avoid cable deformation and internal core wire displacement caused by gaps, and enhance the integrity and appearance quality of the cable. The purpose of wrapping is to increase the overall tightness of the cable and further protect the internal core wires to avoid friction and wear, while providing a better substrate surface for the subsequent sheath extrusion process.

[0099] S8, outer sheath 8 extrusion:

[0100] A 90°C grade thermoplastic elastomer conforming to GB / T 33594 standard is used as the sheath layer 8, so that the sheath layer 8 is tightly squeezed on the outer periphery of the tape layer 7 to form a lightweight liquid-cooled cable for a DC charging pile.

[0101] After the cable is formed, when the liquid-cooled cable for lightweight DC charging pile is used in conjunction with the charging pile, the coolant is filled into the liquid-cooled cable for lightweight DC charging pile through the charging pile, and the coolant flows into the double crescent groove and the gap after several main power core wire conductors 1-2 are twisted together, and directly contacts the main power core wire conductors 1-2, thereby achieving liquid cooling.

[0102] In step S8: the extruder of the outer sheath 8 adopts a single screw extruder with a screw diameter of 120 mm, and the screw aspect ratio is 25:1 to ensure sufficient melting and mixing effects, the feed section temperature is 170°C-190°C, the compression section temperature is 180°C-200°C, the neck section temperature is 190°C-210°C, the mold section temperature is 200°C-220°C, the screw speed is 30-45RPM, the screw linear speed is 8-12m / min, and the specific linear speed is fine-tuned in real time according to the cable diameter and extrusion thickness to ensure that the outer sheath surface is smooth, the size is stable and meets the quality requirements.

[0103] The screw is designed as a conventional three-stage structure, including a feeding section, a compression section and a metering section, to ensure uniform heating and plasticization of the TPE material at each stage. A 36mm sizing mold is selected to ensure precise molding with an outer diameter of approximately 36mm.

[0104] The test results of the embodiment of the present invention are as follows:

[0105] Comparative test verification: DC charging cable with a charging power of 100kW, where the electric vehicle system voltage architecture is 400V, the maximum allowable current of the cable is 250A, and the basic cable structure is 2x80mm 2 +1x25mm 2 +2x2.5mm 2 +2P(2x1mm 2 )+P(8x1mm 2 ), the parameters in the structure are specifically expressed as follows: Main power core line 1 is: 2x80mm 2 , grounding core wire 2: 8x1mm 2 , auxiliary power core wire 3: 2x2.5mm 2 , control core wire group 4 is: 1x25mm 2 , Communication core wire group 5 is: 2x1mm 2 The invention designs a lightweight liquid-cooled cable for DC charging piles. By adding a double crescent skeleton 1-1 of polyperfluoroethylene propylene fluoroplastic inside the conductor, the cooling liquid flow channel area is about 4.8mm 2 The coolant can be immersed in the channel and circulated with the conductor for cooling, and the outer layer of the conductor is covered with a main power core wire insulation layer 1-3 of polytetrafluoroethylene propylene fluoroplastic to isolate the conductor and the coolant from the external cable materials and structures, forming a reliable closed space to effectively prevent the coolant from directly contacting the external structure and materials, avoiding material aging and corrosion caused by long-term contact, thereby optimizing the cable structure to 2x35mm 2 +1x25mm 2 +2x2.5mm 2 +2P(2x1mm 2 )+P(8x1mm 2 ), the main power core conductor 1-2 is 80mm 2 Lowered to 35mm 2 The following tests are conducted to compare the traditional DC charging cable and this implementation case with the same charging power (100kW) and different voltage architectures (400V and 800V) as follows:

[0106] Test equipment: including Delta Elektronika SM500-CP-90 DC power supply, which can support 0-500V voltage and 100kW power output; Chroma 63200A series electronic load equipment, which is used to simulate the charging system of electric vehicles and can support load conditions of 0-1000V voltage and 500A current; in addition, Omega K-type thermocouples are used to monitor the temperature changes of cable conductors and outer sheaths, Hioki CT6875 current sensors are used to monitor the actual current carrying of cables, and FLIR E8 thermal imagers are used to record the temperature distribution of the outer surface of the cable. All data are recorded in real time through Keysight 34972A data loggers.

[0107] Test method: Connect the traditional DC charging cable and the cable of this embodiment to the DC power supply and load equipment respectively, set the current to 250A under 400V voltage condition and set the current to 125A under 800V voltage condition to maintain a constant power of 100kW, and record the conductor temperature rise, outer sheath temperature rise and heat distribution of the two cables within 60 minutes. In the cooling system of the liquid-cooled cable, the coolant circulates through the flow channel inside the double crescent skeleton 1-1 of the polyperfluoroethylene propylene fluoroplastic, and the coolant flow rate is controlled at 0.5-1.0L / min. Dynalene LC high thermal conductivity coolant is used to ensure the cooling effect and avoid material aging.

[0108] Test results: Under 400V conditions, the conductor temperature rise of the original cable reached 92°C after 60 minutes, and the outer sheath temperature rise was 65°C; while the conductor temperature of the new liquid-cooled cable was only about 70°C, and the outer sheath temperature was 45°C, which was significantly lower than the temperature rise data of the original solution. Under 800V conditions, the conductor temperature of the original solution was 75°C and the outer sheath temperature rise was 55°C, while the conductor temperature of the new solution was only 50°C and the outer sheath temperature was 40°C, showing excellent heat dissipation effect. Through data comparison, the conductor temperature rise of the new solution was reduced by about 24°C and the outer sheath temperature rise was reduced by 20°C under 400V conditions, while the conductor temperature rise was reduced by about 25°C and the outer sheath temperature rise was reduced by 15°C under 800V conditions. In addition, the new solution reduces the overall unit weight of the cable by 40%, from 2.8kg / m to 1.7kg / m, and the outer diameter is reduced from 40mm to 36mm, which improves the lightweight and flexibility of the charging pile cable. Under high-voltage and high-power charging conditions, the liquid-cooled cable designed in this implementation case not only has better heat dissipation performance than the original solution, but also effectively isolates the coolant from the conductor through the main power core wire of polyperfluoroethylene propylene fluoroplastics to prevent material aging and corrosion, thereby ensuring the long-term reliability of the cable. Therefore, the test results prove that the liquid-cooled cable for lightweight DC charging piles is significantly superior to the traditional DC cable solution in terms of safety, heat dissipation performance, lightweight and structural optimization, and is particularly suitable for use in future high-power electric vehicle charging systems.

[0109] The cable of the present invention is particularly suitable for immersion liquid cooling solutions, and is intended to solve the problems of aging, corrosion, and high production costs that are prone to occur in existing liquid cooling cables during long-term use. The cable uses polyperfluoroethylene propylene fluoroplastic to make a double crescent skeleton 1-1, which provides support when the conductor is twisted, forming a sufficient and stable space as a liquid cooling channel for the flow of coolant. After the conductor is twisted, polyperfluoroethylene propylene fluoroplastic is first used as the inner insulating material to extrude a very thin coating layer to isolate the conductor and the coolant from the external cable materials and structures, forming a reliable closed space to effectively prevent the coolant from directly contacting the external structure and materials, and avoiding material aging and corrosion caused by long-term contact. Subsequently, a layer of thermoplastic elastomer is extruded outside the main power core wire coating insulation layer 1-3 of polyperfluoroethylene propylene fluoroplastic as the main power core wire main insulation layer 1-4. FEP fluoroplastics have strong chemical resistance and are almost unaffected by most coolants (including those containing ethylene glycol, propylene glycol, water-based coolants and other organic or inorganic compounds). This chemical inertness allows FEP fluoroplastics to be exposed to coolants for a long time without degradation, expansion or dissolution, ensuring the stability of material performance. Moreover, FEP fluoroplastics have low permeability to gases and liquids, which means that it is difficult for coolants to penetrate through FEP fluoroplastics and affect the inner layer of the cable, causing possible electrical failures or other performance problems. In addition, FEP fluoroplastics can maintain their physical and chemical stability over a very wide temperature range (approximately -200°C to +200°C). This design not only utilizes the excellent corrosion resistance of fluoroplastics to avoid the problems caused by the contact between coolants and conventional thermoplastic insulation materials, but also uses thermoplastic elastomers on the outer layer to reduce production costs while maintaining flexibility, avoiding the problems of cable stiffness and high costs caused by FEP insulation. Through this structural design and material combination, the cable not only has good mechanical strength and anti-aging performance, but can also effectively control the temperature of the cable under high-power charging conditions, thereby improving the overall safety and service life of the charging pile.

[0110] The innovation of the present invention lies in the use of two main power core wires with a special double-crescent support structure. When used in conjunction with a charging pile, the coolant flows through the double-crescent skeleton into the gaps after the main power core wire conductors are twisted, thereby liquid-cooling the main power core wire conductors. This immersion coolant solution achieves higher cooling efficiency.

[0111] The innovation of the present invention is that the inner layer uses polyperfluoroethylene propylene fluoroplastic as the insulation layer of the main power core wire to avoid the problems caused by the contact between the coolant and the conventional thermoplastic insulation material, and the outer layer uses thermoplastic elastomer material as the main insulation layer of the main power core wire, so that the cable can maintain flexibility while reducing the production cost, avoiding the problems of cable stiffness and high cost caused by perfluoroplastic insulation. With this structural design and material combination, the cable not only has good mechanical strength and anti-aging performance, but also can effectively control the temperature of the cable under high-power charging conditions, thereby improving the overall safety and service life of the charging pile.

Claims

1. A liquid-cooled cable for a lightweight DC charging pile, characterized in that: The cable core comprises a cable core, a filling layer (6), a tape layer (7) and a sheath layer (8); the cable core is sequentially wrapped with the tape layer (7) and the sheath layer (8), and the filling layer (6) is filled between the tape layer (7) and the cable core; the filling layer (6) is made of PP rope material, the tape layer (7) is made of non-woven fabric material, and the sheath layer (8) is made of thermoplastic elastomer material.

2. A lightweight liquid-cooled cable for a DC charging pile according to claim 1, characterized in that: The cable core comprises two main power core wires (1) with a special double-crescent support structure, a grounding core wire (2), two auxiliary power core wires (3), a control core wire group (4) and two groups of communication core wire groups (5); the two main power core wires (1), the grounding core wire (2), the two auxiliary power core wires (3), the control core wire group (4) and the two groups of communication core wire groups (5) are twisted together, and a filling layer (6) is filled in the twisted gaps.

3. A lightweight liquid-cooled cable for a DC charging pile according to claim 2, characterized in that: The main power core wire (1) comprises a double crescent frame (1-1), a plurality of main power core wire conductors (1-2), a main power core wire coating insulation layer (1-3) and a main power core wire main insulation layer (1-4); the plurality of main power core wire conductors (1-2) are twisted on the outer periphery of the double crescent frame (1-1); the main power core wire conductors (1-2) after twisting are coated with the main power core wire coating insulation layer (1-3); the main power core wire coating insulation layer (1-3) plays a sealing role on the twisted main power core wire conductors (1-2); the main power core wire coating insulation layer (1-3) is wrapped with the main power core wire main insulation layer (1-4); The grounding core wire (2) comprises a grounding core wire conductor (2-1) and a grounding core wire insulation layer (2-2); the grounding core wire conductor (2-1) is wrapped with the grounding core wire insulation layer (2-2); The auxiliary power core wire (3) comprises an auxiliary power core wire conductor (3-1) and an auxiliary power core wire insulation layer (3-2); the auxiliary power core wire conductor (3-1) is wrapped with the auxiliary power core wire insulation layer (3-2); The control core wire group (4) comprises a plurality of control core wire conductors (4-1), a plurality of control core wire insulation layers (4-2), a control core wire aluminum foil shielding layer (4-3), a control core wire braided shielding layer (4-4) and a control core wire inner sheath layer (4-5); each of the control core wire conductors (4-1) is wrapped with a control core wire insulation layer (4-2) to form a plurality of control core wires, and the plurality of control core wires are twisted together, and the twisted control core wires are sequentially wrapped with a control core wire aluminum foil shielding layer (4-3), a control core wire braided shielding layer (4-4) and a control core wire inner sheath layer (4-5); The communication core wire group (5) comprises a plurality of communication core wire conductors (5-1), a plurality of communication core wire insulation layers (5-2), a communication core wire aluminum foil shielding layer (5-3), a communication core wire braided shielding layer (5-4) and a communication core wire inner sheath layer (5-5); each of the communication core wire conductors (5-1) is wrapped with a communication core wire insulation layer (5-2) to form a plurality of communication core wires, the plurality of communication core wires are twisted together, and the twisted gaps are filled with cotton yarns, and the twisted communication core wires are sequentially wrapped with a communication core wire aluminum foil shielding layer (5-3), a communication core wire braided shielding layer (5-4) and a communication core wire inner sheath layer (5-5).

4. A lightweight liquid-cooled cable for a DC charging pile according to claim 3, characterized in that: The material of the double-crescent skeleton (1-1) is polytetrafluoroethylene propylene fluoroplastic; the cross-section of the double-crescent skeleton (1-1) is designed to be a double-crescent shape, and the double-crescent shape has a semicircular groove on both sides of the circular diameter, so that the main body of the double-crescent skeleton (1-1) is used to support the twisted form of the external conductor, and the double-crescent groove designed in the double-crescent skeleton (1-1) is used to circulate cooling liquid to liquid-cool the main power core conductor (1-2) when used in conjunction with a charging pile; the materials of the main insulation layer (1-4) of the main power core, the grounding core insulation layer (2-2), the auxiliary power core insulation layer (3-2), the control core insulation layer (4-2) and the communication core insulation layer (5-2) are all thermoplastic elastomers.

5. The production process of the liquid-cooled cable for the lightweight DC charging pile according to any one of claims 1 to 4 is characterized in that: The method comprises the following steps: S1, double crescent frame (1-1) extrusion: The polyperfluoroethylene propylene fluoroplastic is processed by an extruder to extrude a double crescent skeleton (1-1); S2, main power core conductor (1-2) twisting: Copper wire is used as a main power core wire sub-conductor, a plurality of main power core wire sub-conductors are evenly divided into N groups, the N groups of main power core wire sub-conductors are twisted respectively to form N groups of main power core wire conductors (1-2), and then the N groups of main power core wire conductors (1-2) are evenly dispersed and arranged and twisted on the periphery of a double crescent frame (1-1); S3, main power core wire (1) extrusion: A main power core wire coating insulation layer (1-3) is wrapped around the outer periphery of the twisted main power core wire conductor (1-2), and then a main power core wire main insulation layer (1-4) is wrapped around the outer periphery of the main power core wire coating insulation layer (1-3), thereby forming a main power core wire (1); S4. Extrusion of ground core wire (2): A thermoplastic elastomer is used as a grounding core wire insulation layer (2-2), so that the grounding core wire insulation layer (2-2) is tightly squeezed on the outer periphery of the grounding core wire conductor (2-1) to form a grounding core wire (2); S5, auxiliary power core wire (3) extrusion: A thermoplastic elastomer is used as the auxiliary power core wire insulation layer (3-2), so that the auxiliary power core wire insulation layer (3-2) is tightly squeezed on the outer periphery of the auxiliary power core wire conductor (3-1) to form the auxiliary power core wire (3); S6, control core wire group (4) and communication core wire group (5) are extruded: Insulating layers are tightly squeezed on the peripheries of a control core conductor (4-1) and a communication core conductor (5-1) to form a control core and a communication core; a plurality of control cores are directly twisted, and then an aluminum foil shielding layer and a metal braided mesh are sequentially wrapped around the twisted peripheries, and then an outer sheath is extruded around the metal braided mesh; a plurality of communication cores are directly twisted, and then an aluminum foil shielding layer and a metal braided mesh are sequentially wrapped around the twisted peripheries, and then an outer sheath is extruded around the metal braided mesh; S7, cable core overall twisting: Two main power core wires (1), a ground core wire (2), two auxiliary power core wires (3), a control core wire group (4) and two communication core wire groups (5) are twisted together as a whole, a PP rope is used as a filling layer (6) to fill the gaps between the twisted wires, and a non-woven fabric is used as a wrapping layer (7) to wrap the wires after the twisting is completed; S8, outer sheath (8) extrusion: A thermoplastic elastomer is used as the sheath layer (8), so that the sheath layer (8) is tightly squeezed on the outer periphery of the wrapping layer (7) to form a lightweight liquid-cooled cable for a DC charging pile.

6. The production process of the liquid-cooled cable for a lightweight DC charging pile according to claim 5, characterized in that: In step S1: The extruder of the double crescent skeleton (1-1) adopts a single screw extruder, the ratio of screw length to diameter is 25:1, the screw is designed as a gradual compression type, the feed section temperature is 240°C-260°C, the compression section temperature is 270°C-290°C, the machine neck section temperature is 280°C-300°C, the mold section temperature is 290°C-310°C, the screw speed is 10-20RPM, and the screw linear speed is 0.5-1.0m / min; The cross-section of the double-crescent frame (1-1) is designed to be a double-crescent shape, wherein the double-crescent shape has a semicircular groove on each side along the circular diameter, and the semicircular groove is used to circulate cooling liquid to perform liquid cooling on the main power core conductor (1-2) when used in conjunction with a charging pile.

7. The production process of the liquid-cooled cable for a lightweight DC charging pile according to claim 5, characterized in that: The step S3 is specifically as follows: A polyperfluoroethylene propylene fluoroplastic is used as the main power core wire coating insulation layer (1-3), so that the outer periphery of the main power core wire conductor (1-2) after the main power core wire coating insulation layer (1-3) is twisted, a thermoplastic elastomer material is used as the main power core wire main insulation layer (1-4), and the main power core wire coating insulation layer (1-3) extrusion host and the main power core wire main insulation layer (1-4) extrusion host are arranged in parallel, and when the polyperfluoroethylene propylene fluoroplastic is still in a high-temperature molten soft state , the thermoplastic elastomer material is immediately extruded through the main insulation layer (1-4) of the main power core wire by the extrusion host, and the thermoplastic elastomer material is coated and fused to the outer periphery of the polytetrafluoroethylene propylene fluoroplastic of the main insulation layer (1-4) of the main power core wire in a high-temperature molten state, thereby ensuring that the polytetrafluoroethylene propylene fluoroplastic of the main power core wire coating insulation layer (1-3) and the polytetrafluoroethylene propylene fluoroplastic of the main insulation layer (1-4) of the main power core wire are integrated to form the final main power core wire (1).

8. The production process of the liquid-cooled cable for a lightweight DC charging pile according to claim 7, characterized in that: In step S3: The main power core wire insulation layer (1-3) is extruded by a high-temperature extruder, with a feed section temperature of 220°C-250°C, a compression section temperature of 250°C-280°C, a neck section temperature of 280°C-300°C, a mold section temperature of 300°C-350°C, a screw speed of 20-40RPM, and a cooling water tank temperature of 30-40°C; The main extruder for the main insulation layer (1-4) of the main power core wire adopts a high-temperature extruder, the feed section temperature is 160°C-180°C, the compression section temperature is 180°C-200°C, the neck section temperature is 200°C-220°C, the mold section temperature is 190°C-220°C, the screw speed is 30-50RPM, and the cooling water tank temperature is 20-30°C.

9. The production process of a lightweight liquid-cooled cable for a DC charging pile according to claim 5, characterized in that: The step S6 is specifically as follows: Extrusion of the control core wire group (4): using a thermoplastic elastomer as the control core wire insulation layer (4-2), so that the control core wire insulation layer (4-2) is tightly squeezed on the periphery of the control core wire conductor (4-1) to form the control core wire, directly twisting a plurality of control core wires, and after twisting, wrapping the outer layer with aluminum foil Mylar in a wrapping manner to form a control core wire aluminum foil shielding layer (4-3), adding a metal braided mesh on the periphery of the control core wire aluminum foil shielding layer (4-3) to form a control core wire braided shielding layer (4-4), using a thermoplastic elastomer as the control core wire inner sheath layer (4-5), so that the control core wire inner sheath layer (4-5) is tightly squeezed on the periphery of the control core wire braided shielding layer (4-4) to form the control core wire group (4); Extrusion of a communication core wire assembly (5): A thermoplastic elastomer is used as a communication core wire insulation layer (5-2), so that the communication core wire insulation layer (5-2) is tightly squeezed on the outer periphery of a communication core wire conductor (5-1) to form a communication core wire, a plurality of communication core wires are directly twisted, and cotton yarn is used for filling during twisting. After twisting, the outer layer is wrapped with aluminum foil Mylar in a wrapping manner to form a communication core wire aluminum foil shielding layer (5-3), a metal braided mesh is added to the outer periphery of the communication core wire aluminum foil shielding layer (5-3) to form a communication core wire braided shielding layer (5-4), a thermoplastic elastomer is used as a communication core wire inner sheath layer (5-5), and the communication core wire inner sheath layer (5-5) is extruded from the outer periphery of the communication core wire braided shielding layer (5-4) to form a communication core wire assembly (5).

10. The production process of a liquid-cooled cable for a lightweight DC charging pile according to claim 5, characterized in that: In step S8: The extruder of the outer sheath (8) adopts a single screw extruder with a screw diameter of 120 mm, a screw length-diameter ratio of 25:1, a feed section temperature of 170°C-190°C, a compression section temperature of 180°C-200°C, a machine neck section temperature of 190°C-210°C, a mold section temperature of 200°C-220°C, a screw speed of 30-45RPM, and a screw linear speed of 8-12m / min.

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