A fast-charging liquid-cooled cable for DC charging piles and its preparation method

Abstract

This application provides a liquid-cooled cable for DC charging piles and its manufacturing method. The liquid-cooled cable includes a conductor, an outer sheath covering the conductor, and a sheath covering the outer sheath. The conductor is composed of multiple conductors, a liquid cooling assembly, and a temperature measuring signal line twisted together. The liquid cooling assembly includes a main liquid cooling pipe and auxiliary liquid cooling pipes. By wrapping the main liquid cooling pipe around the outer periphery of the conductor and setting multiple auxiliary liquid cooling pipes spaced apart from the conductor, coolant can be placed in the main liquid cooling pipe and auxiliary liquid cooling pipes when the cable is in operation, so as to reduce the internal temperature of the conductor and prevent short circuits and fires in the charging pile during the fast charging process of new energy vehicles, thereby improving the charging efficiency and safety of new energy vehicle charging piles. The liquid-cooled cable manufacturing method includes four steps: conductor preparation, sheath extrusion material preparation, conductor preparation, and cable preparation. It has the advantages of simple operation, excellent cooling effect, and is conducive to the promotion of fast charging and easy to implement.

Description

Technical Field

[0001] This application belongs to the field of cable manufacturing technology for new energy vehicle charging piles, specifically relating to a DC charging pile fast-charging liquid-cooled cable and its preparation method. Background Technology

[0002] In the existing technology, with the rapid development of lithium battery technology, new energy vehicles are now widely used. With the significant increase in the demand for cables for new energy vehicles, in order to ensure the driving safety and charging safety of new energy vehicles, the requirements for the heat dissipation of cables for new energy vehicle charging piles are becoming increasingly higher.

[0003] Compared with traditional vehicles, new energy vehicles have advantages such as strong power, low cost, and energy saving and environmental protection. However, the development of new energy vehicles is limited by their low charging efficiency. To solve the problem of charging time for new energy vehicles, it is necessary to design and develop high-power charging cables. However, in actual implementation, conventional high-power charging pile cables have large outer diameters and high weight. During the high-power fast charging process of new energy vehicles, the cable cores heat up severely, resulting in low current carrying capacity and easy short circuits, which can cause fires and greatly limit the charging efficiency of new energy vehicles. In existing technologies, the temperature rise is often reduced by further increasing the cross-section of the cable. On the one hand, this increases the amount of conductor used, raising manufacturing costs. On the other hand, it significantly increases the weight of the cable, making it inconvenient for users. Therefore, improvements are urgently needed. Summary of the Invention

[0004] To address the technical problems in the prior art where high-power charging pile cables have large outer diameters and high weights, making them inconvenient for female users, and where the cable cores overheat during high-power fast charging of new energy vehicles, easily causing short circuits and posing a fire hazard, this application proposes a DC charging pile fast-charging liquid-cooled cable. To further address the technical problems provided in this application, this application also provides a method for preparing the DC charging pile fast-charging liquid-cooled cable.

[0005] This application adopts the following scheme: a DC charging pile fast charging liquid-cooled cable includes a conductor, an outer sheath covering the outer periphery of the conductor, and a sheath covering the outer sheath. The conductor is formed by twisting together multiple conductors, a liquid cooling assembly, and a temperature measuring signal line. Each conductor is covered with an inner sheath. The liquid cooling assembly includes a main cooling pipe covering the outer periphery of the inner sheath and secondary cooling pipes arranged at intervals along the circumference of the conductor. Coolant is disposed in the main cooling pipe and the secondary cooling pipes. The liquid cooling assembly is used to reduce the temperature inside the conductor, and the temperature measuring signal line is used to measure the internal temperature of the conductor.

[0006] Furthermore, the main cooling pipe is made of polytetrafluoroethylene, the auxiliary cooling pipe is made of the same material as the main cooling pipe, the diameter of the main cooling pipe is larger than the diameter of the auxiliary cooling pipe, and the flow rate of the coolant in the main cooling pipe / auxiliary cooling pipe is 0.8-1.8 bar.

[0007] Furthermore, the coolant is soft water or a mixture of soft water and ethylene glycol at a mass ratio of 10:1.5. By adding ethylene glycol to the soft water, on the one hand, the heat transfer medium in the soft water can be increased, further improving the heat transfer efficiency of the main and auxiliary liquid cooling pipes. On the other hand, it can prevent internal corrosion of the main and auxiliary cooling pipes and reduce scale formation.

[0008] Furthermore, the outer diameter R and inner diameter r of the main cooling pipe / the auxiliary cooling pipe satisfy the following relationship: 2r≤R≤4r.

[0009] Furthermore, the space between the outer cladding and the core is filled with a thermally conductive filler, which is composed of the following components by weight: 15-18 parts of α-alumina, 5-12 parts of magnesium oxide, 3-5 parts of aluminum nitride, 3-5 parts of boron nitride, 5-10 parts of carbon powder, 3-5 parts of glass fiber, 1-3 parts of flocculent asbestos, and 10-15 parts of titanate coupling agent.

[0010] Furthermore, the conductor is a Class VI copper conductor, which is formed by twisting multiple copper wires twice, with the diameter of the copper wires used for twisting being 0.1-0.25 mm.

[0011] Furthermore, the pitch ratio of the copper wire in the first stranding process is 30 times, and the direction of the first stranding is to the left. The pitch ratio of the copper wire in the second stranding is 12 times, and the direction of the second stranding is the same as that of the first stranding. By using an active pay-off frame for stranding, the pay-off tension of each copper wire is controlled consistently to prevent conductor jumps in the stranded wires and avoid inconsistent tension during stranding. By using a cage stranding machine, the de-twist ratio during stranding is 100%, which completely releases the internal stress of the conductor and ensures the service life of the conductor.

[0012] Furthermore, the inner cladding is made of a low-density ablation material, and the outer cladding is made of the same material as the inner cladding.

[0013] The low-density ablation material, by weight, comprises the following components: 200-220 parts EPDM rubber, 80-100 parts nitrile rubber, 15-25 parts inorganic flame retardant, 50-55 parts resin, 10-15 parts asbestos, 30-40 parts reinforcing agent, 4-6 parts softener, 17-20 parts inorganic filler, 15-20 parts vulcanizing agent, and 4-5 parts accelerator.

[0014] Furthermore, the preparation method of the low-density ablation material includes the following steps:

[0015] Step 101. Ethylene propylene diene monomer (EPDM) rubber and nitrile rubber are sequentially fed into a screw plasticizer and plasticized at 60-72℃ and 700-1100rpm for 1-2 hours. Then, the mixture is transferred to a disperser and blended at room temperature and 1000-1100rpm for 20-40 minutes to obtain the reaction precursor.

[0016] Step 102. Transfer the reaction precursor prepared in step 101 to a screw mixer. Add asbestos, resin, inorganic flame retardant, inorganic filler, reinforcing agent and softener to the mixer in sequence. Mix for 30-50 minutes at 90-110℃ and 1200-1500rpm. After the initial mixing is completed, add vulcanizing agent and accelerator to the mixer at once. After thorough thin-passing at 110-125℃ and 1400-1600rpm, extrude and cure to obtain the final product.

[0017] Furthermore, the resin is one or a mixture of more than one of the following: polysiloxane resin, bisphenol A type epoxy resin, polyurethane resin, and acrylic resin.

[0018] Furthermore, the overlap rate of the inner wrapping layer A satisfies the following conditions: A≥50%, and even further, A=60%. By controlling the overlap rate of the inner wrapping layer, the thickness of the inner wrapping layer is reduced, ensuring its insulation and flame retardancy while improving its heat dissipation performance.

[0019] Furthermore, the density of the low-density ablation material is 0.93 g / cm³. 3 By compounding various rubbers and resins, its bending strength can reach 1000MPa. When it is wrapped on cables or conductors, the creep of the inner / outer wrapping is very small and it has high tensile strength, which can meet the requirements of charging pile cables for flexibility and flame retardancy.

[0020] Furthermore, the temperature measuring signal line is braided from tin-plated copper wire with a braiding pitch of 45-48mm and a braiding density of ≥95%.

[0021] To address the technical problems raised in this application, this application also proposes a method for preparing a fast-charging liquid-cooled cable for a DC charging pile, comprising the following steps:

[0022] Step 201. Conductor preparation: After arranging the bundled copper wire units in a regular 1+6 pattern, use a cage stranding machine to strand them into a prefabricated conductor in one step, and then strand the prefabricated conductor into a conductor in a second step.

[0023] Step 202. Preparation of wrapped extrusion material: The rubber reaction precursor, inorganic flame retardant, resin, asbestos, reinforcing agent, softener, inorganic filler, vulcanizing agent and accelerator are sequentially added into a mixer and stirred for 10-20 minutes under the conditions of -0.01 MPa, 95-105℃ and 1600-2100 rpm to obtain the wrapped extrusion material.

[0024] Step 203. Core preparation: After the extruded material of the wrapping layer prepared in step 102 is used as the inner wrapping layer and extruded around the outer periphery of the conductor prepared in step 101, the main cooling tube is sleeved around the outer periphery of each conductor. After the main cooling tube is sleeved, the auxiliary cooling tube and the temperature measuring signal line are arranged at intervals with the conductor, and then the thermally conductive filler is used to use a cage stranding machine to strand them into a core.

[0025] Step 204. Cable preparation: The extruded material of the wrapping layer prepared in step 202 is extruded around the outer periphery of the wire core prepared in step 103 to obtain the outer wrapping layer. Then, polyurethane thermoelastic is extruded as a sheath layer around the outer periphery of the outer wrapping layer to obtain the DC charging pile fast charging liquid-cooled cable.

[0026] Compared with the prior art, this application has the following beneficial effects:

[0027] This application provides a liquid-cooled cable for DC charging piles and its manufacturing method. The liquid-cooled cable includes a conductor, an outer sheath covering the conductor, and a sheath covering the outer sheath. The conductor is composed of multiple conductors, a liquid cooling assembly, and a temperature measuring signal line twisted together. The liquid cooling assembly includes a main liquid cooling pipe and auxiliary liquid cooling pipes. By wrapping the main liquid cooling pipe around the outer periphery of the conductor and setting multiple auxiliary liquid cooling pipes spaced apart from the conductor, coolant can be placed in the main liquid cooling pipe and auxiliary liquid cooling pipes when the cable is in operation, so as to reduce the internal temperature of the conductor and prevent short circuits and fires in the charging pile during the fast charging process of new energy vehicles, thereby improving the charging efficiency and safety of new energy vehicle charging piles. The liquid-cooled cable manufacturing method includes four steps: conductor preparation, sheath extrusion material preparation, conductor preparation, and cable preparation. It has the advantages of simple operation, excellent cooling effect, and is conducive to the promotion of fast charging and easy to implement. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0029] Figure 1 This is a cross-sectional schematic diagram of a DC charging pile fast-charging liquid-cooled cable according to this application;

[0030] Figure 2 This is a graph showing the temperature changes at various measurement locations in the fast charging simulation test results of this application. Detailed Implementation

[0031] Combination such as Figure 1-2 As shown, to further illustrate this technical solution, a DC charging pile fast charging liquid-cooled cable includes a conductor 1, an outer sheath 2 covering the outer periphery of the conductor 1, and a sheath 3 covering the outer sheath 2. The conductor 1 is formed by twisting together multiple conductors 10, a liquid cooling assembly 11, and a temperature measuring signal line 12. Each conductor 10 is covered with an inner sheath 13. The liquid cooling assembly 11 includes a main cooling pipe 110 covering the outer periphery of the inner sheath 13, and secondary cooling pipes 111 arranged circumferentially around the conductors of the conductor 1. Coolant is provided inside the main cooling pipe 110 and the secondary cooling pipes 111. The liquid cooling assembly 11 is used to reduce the temperature inside the conductor 1.

[0032] This application provides a liquid-cooled cable for DC charging piles and its manufacturing method. The liquid-cooled cable includes a conductor, an outer sheath covering the conductor, and a sheath covering the outer sheath. The conductor is composed of multiple conductors, a liquid cooling assembly, and a temperature measuring signal line twisted together. The liquid cooling assembly includes a main liquid cooling pipe and auxiliary liquid cooling pipes. By wrapping the main liquid cooling pipe around the outer periphery of the conductor and setting multiple auxiliary liquid cooling pipes spaced apart from the conductor, coolant can be placed in the main liquid cooling pipe and auxiliary liquid cooling pipes when the cable is in operation, so as to reduce the internal temperature of the conductor and prevent short circuits and fires in the charging pile during the fast charging process of new energy vehicles, thereby improving the charging efficiency and safety of new energy vehicle charging piles. The liquid-cooled cable manufacturing method includes four steps: conductor preparation, sheath extrusion material preparation, conductor preparation, and cable preparation. It has the advantages of simple operation, excellent cooling effect, and is conducive to the promotion of fast charging and easy to implement.

[0033] In this embodiment, the main cooling pipe 110 is made of polytetrafluoroethylene, the auxiliary cooling pipe 111 is made of the same material as the main cooling pipe 110, the diameter of the main cooling pipe 110 is larger than the diameter of the auxiliary cooling pipe 111, and the flow rate of the coolant in the main cooling pipe 110 / the auxiliary cooling pipe 111 is 1.0 bar.

[0034] In this embodiment, the outer diameter R and inner diameter r of the main cooling pipe 110 / the auxiliary cooling pipe 111 satisfy the following relationship: 2r≤R≤4r. In actual implementation, R=2r. R=6mm.

[0035] In this embodiment, the conductor 10 is a Class VI copper conductor, which is formed by twisting multiple copper wires twice. The diameter of the copper wires used for twisting is 0.1-0.25mm.

[0036] In actual implementation, the diameter of the copper wire used for stranding is 0.15mm.

[0037] In this embodiment, the temperature measuring signal line 12 is braided from tin-plated copper wire with a braiding pitch of 45-48mm and a braiding density of ≥95%. In actual implementation, the braiding pitch of the temperature measuring signal line is 46mm and the braiding density is 97%.

[0038] Example 1

[0039] 1) Prepare the thermally conductive filler according to the weight parts shown in Table 1, including the following steps:

[0040] Alpha-alumina, magnesium oxide, aluminum nitride, boron nitride, and carbon powder were sequentially added to a homogenizer and homogenized until the particle size was 0.08 mm to obtain a thermally conductive powder. The thermally conductive powder, glass fiber, flocculent asbestos, and titanate coupling agent were sequentially added to an ultrasonic disperser and dispersed for 30 min at 20000 Hz and 41℃. After filtration and drying, a premix was obtained. The premix and PP resin were sequentially added to an extruder at a mass ratio of 1:1.5, mixed, extruded, and granulated to obtain a thermally conductive filler.

[0041] 2) Prepare low-density ablation materials according to the weight parts shown in Table 1, including the following steps:

[0042] Step 101. Ethylene propylene diene monomer (EPDM) rubber and nitrile rubber (NBR) are sequentially fed into a screw plasticizer and plasticized at 61°C and 730 rpm for 2 hours. Then, the mixture is transferred to a disperser and blended at room temperature and 1000 rpm for 40 minutes to obtain the reaction precursor.

[0043] Step 102. Transfer the reaction precursor prepared in step 101 to a screw mixer. Add asbestos, resin, inorganic flame retardant, inorganic filler, reinforcing agent and softener to the mixer in sequence and mix for 50 minutes at 91°C and 1250 rpm. After the initial mixing is completed, add vulcanizing agent and accelerator to the mixer at once. After thorough thin-pass mixing at 112°C and 1425 rpm, extrude and cure to obtain the final product.

[0044] The resin is a mixture of polysiloxane resin, bisphenol A type epoxy resin and polyurethane resin in a mass ratio of 3:1:2.

[0045] 3) A method for preparing a DC charging pile fast-charging liquid-cooled cable, comprising the following steps:

[0046] Step 201. Conductor preparation: After arranging the bundled copper wire units in a regular 1+6 pattern, use a cage stranding machine to strand them into a prefabricated conductor in one step, and then strand the prefabricated conductor into a conductor in a second step.

[0047] Step 202. Preparation of wrapped extrusion material: The rubber reaction precursor, inorganic flame retardant, resin, asbestos, reinforcing agent, softener, inorganic filler, vulcanizing agent and accelerator are sequentially added into the mixer and stirred for 20 minutes under the conditions of -0.01 MPa, 95℃ and 1680 rpm to obtain the wrapped extrusion material.

[0048] Step 203. Core preparation: After the extruded material of the wrapping layer prepared in step 102 is used as the inner wrapping layer and extruded around the outer periphery of the conductor prepared in step 101, the main cooling tube is sleeved around the outer periphery of each conductor. After the main cooling tube is sleeved, the auxiliary cooling tube and the temperature measuring signal line are arranged at intervals with the conductor, and then the thermally conductive filler is used to use a cage stranding machine to strand them into a core.

[0049] Step 204. Cable preparation: The extruded material of the wrapping layer prepared in step 202 is extruded around the outer periphery of the wire core prepared in step 103 to obtain the outer wrapping layer. Then, polyurethane thermoelastic is extruded as a sheath layer around the outer periphery of the outer wrapping layer to obtain the DC charging pile fast charging liquid-cooled cable.

[0050] Example 2

[0051] 1) Prepare the thermally conductive filler according to the weight parts shown in Table 1, including the following steps:

[0052] Alpha-alumina, magnesium oxide, aluminum nitride, boron nitride, and carbon powder were sequentially fed into a homogenizer and homogenized until the particle size was 0.08 mm to obtain a thermally conductive powder. The thermally conductive powder, glass fiber, flocculent asbestos, and titanate coupling agent were sequentially fed into an ultrasonic disperser and dispersed for 21 min at 2160 Hz and 52 °C. After filtration and drying, a premix was obtained. The premix and PP resin were sequentially fed into an extruder at a mass ratio of 1:1.5, mixed, extruded, and granulated to obtain a thermally conductive filler.

[0053] 2) Prepare low-density ablation materials according to the weight parts shown in Table 1, including the following steps:

[0054] Step 101. Ethylene propylene diene monomer (EPDM) rubber and nitrile rubber (NBR) are sequentially fed into a screw plasticizer and plasticized at 65°C and 910 rpm for 1.5 h. The mixture is then transferred to a disperser and blended at room temperature and 1044 rpm for 31 min to obtain the reaction precursor.

[0055] Step 102. Transfer the reaction precursor prepared in step 101 to a screw mixer. Add asbestos, resin, inorganic flame retardant, inorganic filler, reinforcing agent and softener to the mixer in sequence and mix for 41 minutes at 102°C and 1330 rpm. After the initial mixing is completed, add vulcanizing agent and accelerator to the mixer at once. After thorough thin-pass mixing at 117°C and 1530 rpm, extrude and solidify to obtain the final product.

[0056] The resin is a mixture of polysiloxane resin, bisphenol A type epoxy resin and polyurethane resin in a mass ratio of 3:1:2.

[0057] 3) A method for preparing a DC charging pile fast-charging liquid-cooled cable, comprising the following steps:

[0058] Step 201. Conductor preparation: After arranging the bundled copper wire units in a regular 1+6 pattern, use a cage stranding machine to strand them into a prefabricated conductor in one step, and then strand the prefabricated conductor into a conductor in a second step.

[0059] Step 202. Preparation of wrapped extrusion material: The rubber reaction precursor, inorganic flame retardant, resin, asbestos, reinforcing agent, softener, inorganic filler, vulcanizing agent and accelerator are sequentially added into a mixer and stirred for 14 minutes under the conditions of -0.01 MPa, 95-105℃ and 1870 rpm to obtain the wrapped extrusion material.

[0060] Step 203. Core preparation: After the extruded material of the wrapping layer prepared in step 102 is used as the inner wrapping layer and extruded around the outer periphery of the conductor prepared in step 101, the main cooling tube is sleeved around the outer periphery of each conductor. After the main cooling tube is sleeved, the auxiliary cooling tube and the temperature measuring signal line are arranged at intervals with the conductor, and then the thermally conductive filler is used to use a cage stranding machine to strand them into a core.

[0061] Step 204. Cable preparation: The extruded material of the wrapping layer prepared in step 202 is extruded around the outer periphery of the wire core prepared in step 103 to obtain the outer wrapping layer. Then, polyurethane thermoelastic is extruded as a sheath layer around the outer periphery of the outer wrapping layer to obtain the DC charging pile fast charging liquid-cooled cable.

[0062] Example 3

[0063] 1) Prepare the thermally conductive filler according to the weight parts shown in Table 1, including the following steps:

[0064] Alpha-alumina, magnesium oxide, aluminum nitride, boron nitride, and carbon powder are sequentially added to a homogenizer and homogenized until the particle size is 0.13 mm to obtain a thermally conductive powder. The thermally conductive powder, glass fiber, flocculent asbestos, and titanate coupling agent are sequentially added to an ultrasonic disperser and dispersed for 12 min at 2180 Hz and 40-60 ℃. After filtration and drying, a premix is ​​obtained. The premix and PP resin are sequentially added to an extruder at a mass ratio of 1:1.5, mixed, extruded, and granulated to obtain a thermally conductive filler.

[0065] 2) Prepare low-density ablation materials according to the weight parts shown in Table 1, including the following steps:

[0066] Step 101. Ethylene propylene diene monomer (EPDM) rubber and nitrile rubber (NBR) are sequentially fed into a screw plasticizer and plasticized at 70°C and 1060 rpm for 1 hour. Then, the mixture is transferred to a disperser and blended at room temperature and 1080 rpm for 23 minutes to obtain the reaction precursor.

[0067] Step 102. Transfer the reaction precursor prepared in step 101 to a screw mixer. Add asbestos, resin, inorganic flame retardant, inorganic filler, reinforcing agent and softener to the mixer in sequence and mix for 33 minutes at 105°C and 1480 rpm. After the initial mixing is completed, add vulcanizing agent and accelerator to the mixer at once. After thorough thin-pass mixing at 123°C and 1570 rpm, extrude and cure to obtain the final product.

[0068] The resin is a mixture of polysiloxane resin, bisphenol A type epoxy resin and polyurethane resin in a mass ratio of 3:1:2.

[0069] 3) A method for preparing a DC charging pile fast-charging liquid-cooled cable, comprising the following steps:

[0070] Step 201. Conductor preparation: After arranging the bundled copper wire units in a regular 1+6 pattern, use a cage stranding machine to strand them into a prefabricated conductor in one step, and then strand the prefabricated conductor into a conductor in a second step.

[0071] Step 202. Preparation of wrapped extrusion material: The rubber reaction precursor, inorganic flame retardant, resin, asbestos, reinforcing agent, softener, inorganic filler, vulcanizing agent and accelerator are sequentially added into the mixer and stirred for 12 minutes under the conditions of -0.01 MPa, 104℃ and 2050 rpm to obtain the wrapped extrusion material.

[0072] Step 203. Core preparation: After the extruded material of the wrapping layer prepared in step 102 is used as the inner wrapping layer and extruded around the outer periphery of the conductor prepared in step 101, the main cooling tube is sleeved around the outer periphery of each conductor. After the main cooling tube is sleeved, the auxiliary cooling tube and the temperature measuring signal line are arranged at intervals with the conductor, and then the thermally conductive filler is used to use a cage stranding machine to strand them into a core.

[0073] Step 204. Cable preparation: The extruded material of the wrapping layer prepared in step 202 is extruded around the outer periphery of the wire core prepared in step 103 to obtain the outer wrapping layer. Then, polyurethane thermoelastic is extruded as a sheath layer around the outer periphery of the outer wrapping layer to obtain the DC charging pile fast charging liquid-cooled cable.

[0074] Table 1. Composition of each component in Examples 1-3

[0075]

[0076] The cable prepared in Example 3 was subjected to the following fast charging simulation test: A 2.5m long cable prepared in Example 3 was used to charge a new energy vehicle for 20 minutes at room temperature, with a load current of 800A, water as the coolant in the main and auxiliary cooling pipes, and a coolant flow rate of 1 bar. The internal temperature change of the cable core was recorded using a temperature measuring signal line. The temperatures at the charging gun head (DC+), charging gun head (DC-), cable tail (DC+), cable tail (DC-), the outer periphery of the cable sheath, and the socket tail were also recorded after the charging current stabilized. The test results are shown in Table 2 and... Figure 2 As shown.

[0077] Table 2 Test Results

[0078]

[0079]

[0080] From Table 2 and Figure 2 Test results show that by setting main and auxiliary liquid cooling pipes inside the conductor core, using polytetrafluoroethylene (PTFE) as the material for both pipes, employing low-density ablative material as the core wrapping layer, and filling the core with a thermally conductive filler composed of thermally conductive particles, the heat generated by the conductor under high load can be quickly conducted to the outside. The thermally conductive filler then rapidly removes the heat from the conductor and transfers it to the coolant within the main and auxiliary liquid cooling pipes, reducing the conductor's operating temperature and ensuring normal operation under high load conditions. Compared to existing PVC cables, the cable provided in this application meets the flexibility and safety requirements for charging pile cables, operates at 800A without increasing the conductor's cross-sectional area, has a low weight, is easy for female users to use, and offers high safety. Existing PVC cables typically have a load capacity of only 600A. The cable provided in this application can effectively improve the charging speed of new energy vehicles, facilitating further promotion of these vehicles.

[0081] 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 DC charging pile fast-charging liquid-cooled cable, characterized in that, The device includes a wire core (1), an outer wrapping layer (2) covering the outer periphery of the wire core (1), and a sheath layer (3) covering the outer wrapping layer (2). The wire core (1) is formed by twisting together multiple conductors (10), a liquid cooling assembly (11), and a temperature measuring signal line (12). Each conductor (10) is covered with an inner wrapping layer (13). The liquid cooling assembly (11) includes a main cooling pipe (110) covering the outer periphery of the inner wrapping layer (13) and secondary cooling pipes (111) arranged at intervals from the conductors (10) along the circumference of the wire core (1). Cooling liquid is provided in the main cooling pipe (110) and the secondary cooling pipes (111). The liquid cooling assembly (11) is used to reduce the temperature inside the wire core (1). The outer cladding (2) and the core (1) are filled with a thermally conductive filler (4). The thermally conductive filler (4) is composed of the following components by weight: 15-18 parts of α-alumina, 5-12 parts of magnesium oxide, 3-5 parts of aluminum nitride, 3-5 parts of boron nitride, 5-10 parts of carbon powder, 3-5 parts of glass fiber, 1-3 parts of flocculent asbestos, and 10-15 parts of titanate coupling agent.

2. The DC charging pile fast-charging liquid-cooled cable according to claim 1, characterized in that, The main cooling pipe (110) is made of polytetrafluoroethylene, and the auxiliary cooling pipe (111) is made of the same material as the main cooling pipe (110). The diameter of the main cooling pipe (110) is larger than that of the auxiliary cooling pipe (111). The flow rate of the coolant in the main cooling pipe (110) / auxiliary cooling pipe (111) is 0.8-1.8 bar.

3. The DC charging pile fast-charging liquid-cooled cable according to claim 1, characterized in that, The outer diameter R and inner diameter r of the main cooling pipe (110) / the auxiliary cooling pipe (111) satisfy the following relationship: 2r≤R≤4r.

4. The DC charging pile fast-charging liquid-cooled cable according to claim 1, characterized in that, The conductor (10) is a Class VI copper conductor. The conductor (10) is formed by twisting multiple copper wires twice. The diameter of the copper wires used for twisting is 0.1-0.25 mm.

5. The DC charging pile fast-charging liquid-cooled cable according to claim 1, characterized in that, The inner cladding (13) is made of a low-density ablation material, and the outer cladding (2) is made of the same material as the inner cladding (13). The low-density ablation material, by weight, comprises the following components: 200-220 parts EPDM rubber, 80-100 parts nitrile rubber, 15-25 parts inorganic flame retardant, 50-55 parts resin, 10-15 parts asbestos, 30-40 parts reinforcing agent, 4-6 parts softener, 17-20 parts inorganic filler, 15-20 parts vulcanizing agent, and 4-5 parts accelerator.

6. The DC charging pile fast-charging liquid-cooled cable according to claim 5, characterized in that, The preparation method of the low-density ablation material includes the following steps: Step 101. Ethylene propylene diene monomer (EPDM) rubber and nitrile rubber are sequentially fed into a screw plasticizer and plasticized at 60-72℃ and 700-1100rpm for 1-2 hours. Then, the mixture is transferred to a disperser and blended at room temperature and 1000-1100rpm for 20-40 minutes to obtain the reaction precursor. Step 102. Transfer the reaction precursor prepared in step 101 to a screw mixer. Add asbestos, resin, inorganic flame retardant, inorganic filler, reinforcing agent and softener to the mixer in sequence. Mix for 30-50 minutes at 90-110℃ and 1200-1500rpm. After the initial mixing is completed, add vulcanizing agent and accelerator to the mixer at once. After thorough thin-passing at 110-125℃ and 1400-1600rpm, extrude and cure to obtain the final product.

7. The DC charging pile fast-charging liquid-cooled cable according to claim 6, characterized in that, The resin is one or a mixture of more than one of the following: polysiloxane resin, bisphenol A type epoxy resin, polyurethane resin, and acrylic resin.

8. The DC charging pile fast-charging liquid-cooled cable according to claim 1, characterized in that, The temperature measurement signal line (12) is woven from tin-plated copper wire with a weaving pitch of 45-48 mm and a weaving density of ≥95%.

9. A method for preparing a DC charging pile fast-charging liquid-cooled cable according to any one of claims 1-8, characterized in that, Includes the following steps: Step 201. Conductor preparation: After arranging the bundled copper wire units in a 1+6 regular pattern, use a cage stranding machine to strand them into a prefabricated conductor in one step, and then strand the prefabricated conductor into a conductor in a second step. Step 202. Preparation of wrapped extrusion material: The rubber reaction precursor, inorganic flame retardant, resin, asbestos, reinforcing agent, softener, inorganic filler, vulcanizing agent and accelerator are sequentially added into a mixer and stirred for 10-20 minutes under the conditions of -0.01 MPa, 95-105℃ and 1600-2100 rpm to obtain the wrapped extrusion material. Step 203. Core preparation: After the extruded material of the wrapping layer prepared in step 102 is used as the inner wrapping layer and extruded around the outer periphery of the conductor prepared in step 101, the main cooling tube is sleeved around the outer periphery of each conductor. After the main cooling tube is sleeved, the auxiliary cooling tube and the temperature measuring signal line are arranged at intervals with the conductor, and then the thermally conductive filler is used to use a cage stranding machine to strand them into a core. Step 204. Cable preparation: The extruded material of the wrapping layer prepared in step 202 is extruded around the outer periphery of the wire core prepared in step 103 to obtain the outer wrapping layer. Then, polyurethane thermoelastic is extruded as a sheath layer around the outer periphery of the outer wrapping layer to obtain the DC charging pile fast charging liquid-cooled cable.

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