Cooling medium voltage shore power charging cable for winding mobile applications

Abstract

This invention relates to the field of charging cable technology, and in particular to a cooled medium-voltage shore power charging cable for use in winding and mobile applications. It includes a central load-bearing unit, a power transmission layer, an insulation layer, a shielding layer, and an outer sheath arranged coaxially from the inside out. It also includes a segmented distributed liquid cooling system, a modified dielectric phase change cooling medium, a winding adaptive reinforcement structure, and a multi-dimensional intelligent monitoring unit. This invention employs a 20m unit segmented distributed liquid cooling system, combined with phase change heat dissipation and a nano-thermal conductive coating, effectively reducing circulating voltage drop and controlling the temperature difference of the 50-150m cable within ±2℃. This improves heat dissipation efficiency and current carrying capacity, meeting the demands of high-power charging. The modified dielectric phase change cooling medium has a dielectric strength ≥35kV / mm, eliminating the risk of leakage and short circuits. The semi-conductive buffer water-blocking band homogenizes the electric field and blocks water vapor, completely eliminating electrical safety hazards under medium- and high-voltage conditions.

Description

Technical Field

[0001] This invention relates to the field of charging cable technology, and in particular to a cooled medium-voltage shore power charging cable for use in winding and moving applications. Background Technology

[0002] With increasingly stringent environmental regulations for ports worldwide, the use of shore power by ships at berth has become an important measure to reduce carbon and pollutant emissions. However, due to the varied berthing locations of ships, shore power cables typically need to be 50-150 meters long and operate at medium to high voltage levels (6kV-15kV), with charging power reaching megawatt levels or higher.

[0003] In existing technologies, DC fast charging for new energy vehicles uses liquid-cooled charging cables. These cables utilize circulating coolant to remove heat generated by the cable and can handle currents of 400A-600A. However, the cable length is typically only 3-7 meters. Directly applying these cables to shore power applications faces two major technical bottlenecks: First, with lengths exceeding 50 meters, the coolant temperature rises significantly along the cable path. Traditional single-point-inlet liquid cooling structures cannot guarantee effective heat dissipation throughout the entire process. Furthermore, leaks of traditional conductive coolants at medium to high voltage levels can cause serious electrical short circuits. Second, shore power cables require frequent winding and unwinding. The rigid cooling pipe structure of existing liquid-cooled cables is prone to fatigue fracture under repeated bending conditions. The pipes are also prone to scaling and blockage, and there is a lack of early warning mechanisms for seal failure, making it difficult to meet the requirements for winding and unwinding.

[0004] Currently, there are various patents for cable winding and unwinding devices in the shore power field. However, these devices all use conventional cables and only focus on optimizing the structure of the winding and unwinding device. They have not solved the problems of high-power liquid cooling heat dissipation compatibility with medium and high voltage insulation, pipeline fatigue under winding conditions, and lack of sealing warning. Summary of the Invention

[0005] The technical problems to be solved by this invention are: large pressure drop in cooling medium circulation, scaling in cooling pipes, lack of early warning for seal failure, uneven electric field distribution, and lagging long-distance operation and maintenance monitoring.

[0006] The technical solution adopted by this invention to solve its technical problem is: a cooled medium-voltage shore power charging cable for winding and moving applications, comprising a central load-bearing unit, a power transmission layer, an insulation layer, a shielding layer, and an outer sheath arranged coaxially from the inside to the outside, and further comprising a segmented distributed liquid cooling system, a modified dielectric phase change cooling medium, a winding adaptive reinforcement structure, and a full-dimensional intelligent monitoring unit; the segmented distributed liquid cooling system is arranged in 20m units along the cable length, with axial cooling units evenly arranged circumferentially; a semi-conductive buffer water-blocking strip is added between the shielding layer and the insulation layer; the full-dimensional intelligent monitoring unit integrates an edge computing early warning module.

[0007] The surface of the heat-conducting metal plate of the axial cooling unit is coated with a nano-thermal-conducting ceramic coating. The heat-conducting metal plate has a wave-shaped structure, with the crests of the waves adhering to the surface of the power transmission layer core and the troughs accommodating the flexible corrugated cooling pipes.

[0008] The inner wall of the flexible corrugated cooling pipe is provided with a hydrophobic and oleophobic anti-scaling layer. The cooling pipe is made of polytetrafluoroethylene or stainless steel corrugated pipe with a wall thickness of 0.3-0.8mm and a bending radius ≤ 5 times the pipe diameter.

[0009] The central load-bearing unit is covered with a low-friction drag-reducing coating and is made of aramid fiber bundles.

[0010] The wound adaptive reinforcement structure includes a helical spring sheath and an elastic buffer silicone layer, wherein the elastic buffer silicone layer is filled between the helical spring sheath and the outer sheath.

[0011] The modified dielectric phase change cooling medium is R134a, R1234yf, or R245fa with added nano-insulating and thermally conductive particles, and has a dielectric strength ≥35kV / mm.

[0012] The flexible corrugated cooling pipe is connected to a multi-stage sealing and early warning assembly at both ends, and the multi-stage sealing and early warning assembly is flexibly connected to the cooling medium circulation system.

[0013] The all-dimensional intelligent monitoring unit includes distributed fiber optic temperature sensors, flow difference leakage sensors, and pipeline pressure sensors, with one temperature measurement point deployed every meter along the cable axis.

[0014] The shielding layer is a copper wire braided layer with a braiding density of ≥95%, and the insulation layer is made of cross-linked polyethylene.

[0015] The outer sheath surface is coated with a UV-cured anti-slip and wear-resistant coating, and the outer sheath is made of neoprene rubber or polyurethane.

[0016] The beneficial effects of this invention are as follows: A segmented distributed liquid cooling system, combined with a dielectric phase-change cooling medium and a semi-conductive buffer water-blocking strip, is used to reduce pressure drop through independent circulation every 20m, with the temperature difference controlled within ±2℃ throughout the process. Simultaneously, a dielectric strength ≥35kV / mm eliminates the risk of leakage and short circuits, effectively solving the problem of compatibility between long-distance liquid cooling and medium-high voltage insulation. Flexible corrugated cooling pipes, combined with a wave-shaped heat-conducting metal plate, an elastic buffer silicone layer, and multi-level sealing and early warning components, enable the cable fatigue life to exceed 150,000 cycles. A hydrophobic and oleophobic anti-scaling layer prevents pipe blockage, and the edge computing early warning module achieves fault location accuracy ≤1m, solving the problems of pipe fatigue, scaling, and lack of sealing early warning under winding conditions. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] Figure 1 This is a schematic diagram of the structure of the present invention.

[0019] Figure 2 This is a partial connection diagram of the all-dimensional intelligent monitoring unit in this invention.

[0020] Figure 3 This is a partial schematic diagram of the connection end of the segmented circulation control valve in this invention.

[0021] In the diagram: 1. Central load-bearing unit; 2. Power transmission layer; 3. Insulation layer; 4. Shielding layer; 5. Segmented distributed liquid cooling system; 6. Outer sheath; 7. Distributed fiber optic temperature sensor; 8. Helical spring sheath; 9. Nano-thermal conductive ceramic coating; 10. Hydrophobic and oleophobic anti-scaling layer; 11. Elastic buffer silicone layer; 12. Pipeline pressure sensor; 13. Edge computing early warning module; 14. Low friction drag-reducing coating; 15. Semi-conductive buffer water-blocking strip; 16. Segmented circulation control valve; 17. Multi-stage sealing early warning component; 18. Nano-insulating thermally conductive particles; 19. UV-cured anti-slip and wear-resistant coating; 51. Flexible corrugated cooling pipe; 71. Flow differential leakage sensor. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0023] Figure 1 , Figure 2 and Figure 3 The cable shown is a cooled medium-voltage shore power charging cable for use in winding and moving applications. It has a coaxial circular structure and consists of, from the inside out, a central load-bearing unit 1, a power transmission layer 2, an insulation layer 3, a semi-conductive buffer water-blocking strip 15, a shielding layer 4, and an outer sheath 6. The cable integrates a segmented distributed liquid cooling system 5 inside, and the outer winding section is equipped with a winding adaptive reinforcement structure. The entire cable is equipped with a full-dimensional intelligent monitoring unit.

[0024] The central load-bearing unit 1 is located at the core of the cable and is made of high-strength aramid fiber bundles. The outer periphery of the central load-bearing unit 1 is tightly covered with a low-friction drag-reducing coating 14. The low-friction drag-reducing coating 14 is made of polytetrafluoroethylene drag-reducing material with a thickness of 0.2mm–0.5mm. It is used to reduce the friction and wear between the internal core and the load-bearing unit when the cable is bent, and at the same time improve the overall tensile and lateral pressure resistance of the cable. It can withstand a long-term tensile load of not less than 20kN and meet the tensile force requirements when winding and moving over a long distance of 50–150m.

[0025] The power transmission layer 2 is located outside the central load-bearing unit 1. It consists of three fan-shaped phase conductors and one fan-shaped neutral conductor arranged symmetrically around the periphery. All four conductors have fan-shaped cross-sections and are spliced ​​together to form a circular whole, effectively reducing the outer diameter of the cable. The conductors are made of oxygen-free copper rods tightly stranded together, with a conductivity of not less than 97% IACS, ensuring low loss during high-power transmission.

[0026] The axial cooling units of the segmented distributed liquid cooling system 5 are evenly arranged in the gaps between adjacent fan-shaped conductors, with 1–2 axial cooling units set between every two conductors. The axial cooling unit includes a corrugated thermally conductive metal plate, a flexible corrugated cooling pipe 51, and a high thermal conductivity insulating silicone grease layer. The thermally conductive metal plate is made of aluminum alloy or copper alloy, and the surface is coated with a nano-thermal conductive ceramic coating 9 with a coating thickness of 10μm–30μm and a thermal conductivity of not less than 30W / (m·K), while also having a dielectric strength of not less than 30kV / mm. The thermally conductive metal plate is corrugated, with the crest surface closely attached to the outer surface of the conductor of the power transmission layer 2, and the trough position is used to embed the flexible corrugated cooling pipe 51. The corrugated structure can deform with the bending of the cable, absorb bending stress, and avoid fatigue cracking.

[0027] The flexible corrugated cooling pipe 51 is tightly embedded in the trough of the heat-conducting metal plate. It is made of polytetrafluoroethylene corrugated pipe with a wall thickness of 0.3mm-0.8mm or thin-walled stainless steel corrugated pipe. The corrugation depth is 15%-25% of the outer diameter of the pipe, and the minimum bending radius is no more than 5 times the pipe diameter to meet the requirements of frequent winding conditions. The inner wall of the flexible corrugated cooling pipe 51 is integrally formed with a hydrophobic and oleophobic anti-scaling layer 10. The anti-scaling layer adopts a fluorinated nano-coating with a thickness of 5μm-15μm, which can effectively inhibit the adhesion and scaling of impurities and water vapor on the inner wall of the pipe in the port environment, and ensure the long-term stable flow of the cooling medium.

[0028] The flexible corrugated cooling pipe 51 is filled with a modified dielectric phase change cooling medium. The medium is based on R134a, R1234yf or R245fa, and uniformly dispersed nano-insulating thermally conductive particles 18. The nano-insulating thermally conductive particles 18 are selected from boron nitride or aluminum oxide nanoparticles, with an addition mass fraction of 1%–5%. This makes the dielectric strength of the modified cooling medium ≥35kV / mm and the latent heat of phase change ≥200kJ / kg. After absorbing the heat of the conductor, it quickly undergoes a liquid-gas phase change to achieve efficient heat dissipation. Even if leakage occurs, it will not cause medium- or high-voltage electrical short circuits.

[0029] The segmented distributed liquid cooling system 5 is equipped with a segmented circulation control valve 16 every 20m along the cable length, dividing the cable into multiple independent cooling units. Each cooling unit forms an independent circulation branch, reducing the pressure drop of the cooling medium during long-distance transportation, ensuring uniform heat dissipation throughout the 50–150m length, and controlling the temperature difference within ±2℃ throughout the entire length. The segmented circulation control valve 16 adopts an electric flow regulating valve, which can automatically adjust the medium flow rate according to the temperature monitoring signal to achieve intelligent variable flow heat dissipation.

[0030] The insulation layer 3 is extruded on the outside of the power transmission layer 2 and the axial cooling unit. It is made of cross-linked polyethylene (XLPE) material. The thickness of the insulation layer is designed to match the voltage levels of 6kV–15kV. The thickness is not less than 2.0mm for 6kV level and not less than 3.5mm for 15kV level. The long-term allowable operating temperature of the insulation layer is not lower than 90℃. It has excellent electrical insulation performance and heat aging resistance.

[0031] The semi-conductive buffer water-blocking tape 15 is wrapped between the insulation layer 3 and the shielding layer 4. It is made of semi-conductive ethylene propylene rubber-based water-blocking tape with a wrapping overlap rate of 20%–30%. On the one hand, it homogenizes the electric field distribution inside the cable and avoids local electric field concentration. On the other hand, it plays a role in blocking water and buffering, preventing seawater and moisture from entering the insulation layer 3 and improving the stability of medium and high voltage operation.

[0032] The shielding layer 4 adopts a copper wire braided structure with a braiding density of ≥95% and a copper wire diameter of 0.15mm–0.25mm. It is used to shield the leakage of internal electromagnetic fields, reduce electromagnetic interference to surrounding equipment, and at the same time provide mechanical support to protect the internal insulation layer 3 from external damage.

[0033] The winding section where the cable and the reel cooperate is equipped with a winding self-adaptive reinforcement structure, including a helical spring sheath 8 and an elastic buffer silicone layer 11. The helical spring sheath 8 is fitted around the outer sheath 6, is made of spring steel, has a pitch of 1.2–1.5 times the outer diameter of the cable, and a spring wire diameter of 3mm–8mm. The elastic buffer silicone layer 11 is filled between the helical spring sheath 8 and the outer sheath 6, with a thickness of 1.5mm–3mm, and is used to absorb radial extrusion force and bending stress during winding, prevent the cable from being excessively flattened or twisted, and protect the internal flexible corrugated cooling tube 51 from breakage.

[0034] Multi-stage sealing early warning components 17 are installed at the connection points of the flexible corrugated cooling pipe 51 with the shore power supply end circulation system. The multi-stage sealing early warning components 17 adopt a mechanical seal structure with two or more layers and integrate pressure sensing and displacement monitoring units. When the seal is worn or loose, an early warning signal is output in real time to realize early warning of seal failure and avoid leakage of cooling medium.

[0035] The all-dimensional intelligent monitoring unit includes a distributed fiber optic temperature sensor 7, a pipeline pressure sensor 12, a flow difference leakage sensor 71, and an edge computing early warning module 13. The distributed fiber optic temperature sensor 7 uses a Bragg fiber grating array, with one temperature measuring point per meter along the three axes of the insulation layer, achieving a temperature measurement accuracy of ±0.5℃. It monitors the temperature distribution throughout the cable in real time and identifies local hot spots. The pipeline pressure sensor 12 is installed at the inlet and outlet of the cooling medium circulation pipeline, with a monitoring range of 0–3.0MPa, providing real-time feedback on pipeline pressure fluctuations. The flow difference leakage sensor 71 compares the flow rates of the medium at the inlet and outlet of the pipeline, and determines leakage when the flow difference exceeds a set threshold. All monitoring signals are transmitted to the edge computing early warning module 13 in real time. The edge computing early warning module 13 has a built-in algorithm model to realize real-time judgment, fault location, and audible and visual early warning of abnormal temperature, abnormal pressure, medium leakage, and seal failure. The fault location accuracy is ≤1m, and the data can be uploaded to the shore power management platform for remote monitoring.

[0036] The outer sheath 6 is made of neoprene rubber (CR) or polyurethane (PU) material through extrusion molding, with a thickness of 2.0mm–4.0mm. It has excellent resistance to seawater, oil, aging, and mechanical wear. The outer sheath 6 is coated with a UV-cured anti-slip and wear-resistant coating 19 with a coating thickness of 30μm–80μm, which further enhances its UV resistance, anti-slip properties, and scratch resistance, making it suitable for harsh operating environments such as open-air ports, salt spray, oil pollution, and sun exposure.

[0037] In this embodiment, the cable has a rated voltage of 6kV–15kV, a rated current carrying capacity of 1000A–1200A, an applicable length of 50–150m, a winding fatigue life of no less than 150,000 cycles, and a total heat dissipation temperature difference of ≤±2℃, which fully meets the requirements for high-voltage shore power charging and frequent winding and movement of ships in port.

Claims

1. A cooled medium-voltage shore power charging cable for use in winding and moving applications, comprising a central load-bearing unit (1), a power transmission layer (2), an insulation layer (3), a shielding layer (4), and an outer sheath (6) arranged coaxially from the inside to the outside, characterized in that, It also includes a segmented distributed liquid cooling system (5), a modified dielectric phase change cooling medium, a wound adaptive reinforcement structure, and a full-dimensional intelligent monitoring unit; the segmented distributed liquid cooling system (5) is arranged in 20m units along the cable length, and axial cooling units are evenly arranged in the circumference; a semi-conductive buffer water-blocking strip (15) is added between the shielding layer (4) and the insulation layer (3); the full-dimensional intelligent monitoring unit integrates an edge computing early warning module (13).

2. A cooled medium-voltage shore power charging cable for use in winding and moving applications according to claim 1, characterized in that, The surface of the heat-conducting metal plate of the axial cooling unit is coated with a nano-thermal-conducting ceramic coating (9). The heat-conducting metal plate has a wave-shaped structure, with the peaks of the waves adhering to the surface of the core of the power transmission layer (2) and the troughs accommodating the flexible corrugated cooling pipe (51).

3. A cooled medium-voltage shore power charging cable for use in winding and moving applications according to claim 2, characterized in that, The inner wall of the flexible corrugated cooling pipe (51) is provided with a hydrophobic and oleophobic anti-scaling layer (10). The cooling pipe is made of polytetrafluoroethylene or stainless steel corrugated pipe with a wall thickness of 0.3-0.8mm and a bending radius ≤ 5 times the pipe diameter.

4. A cooled medium-voltage shore power charging cable for use in winding and moving applications according to claim 1, characterized in that, The central load-bearing unit (1) is covered with a low-friction drag-reducing coating (14), and the central load-bearing unit (1) is made of aramid fiber bundles.

5. A cooled medium-voltage shore power charging cable for use in winding and moving applications according to claim 1, characterized in that, The wound adaptive reinforcement structure includes a helical spring sheath (8) and an elastic buffer silicone layer (11), wherein the elastic buffer silicone layer (11) is filled between the helical spring sheath (8) and the outer sheath (6).

6. A cooled medium-voltage shore power charging cable for use in winding and moving applications according to claim 1, characterized in that, The modified dielectric phase change cooling medium is R134a, R1234yf or R245fa with added nano-insulating thermally conductive particles (18), and has a dielectric strength ≥35kV / mm.

7. A cooled medium-voltage shore power charging cable for use in winding and moving applications according to claim 2, characterized in that, The flexible corrugated cooling pipe (51) is connected to a multi-stage sealing early warning assembly (17) at both ends, and the multi-stage sealing early warning assembly (17) is flexibly connected to the cooling medium circulation system.

8. A cooled medium-voltage shore power charging cable for use in winding and moving applications according to claim 1, characterized in that, The all-dimensional intelligent monitoring unit includes a distributed fiber optic temperature sensor (7), a flow difference leakage sensor (71), and a pipeline pressure sensor (12), with one temperature measurement point laid out every meter along the cable axis.

9. A cooled medium-voltage shore power charging cable for use in winding and moving applications according to claim 1, characterized in that, The shielding layer (4) is a copper wire braided layer with a braiding density of ≥95%, and the insulation layer (3) is made of cross-linked polyethylene.

10. A cooled medium-voltage shore power charging cable for use in winding and moving applications according to claim 1, characterized in that, The outer sheath (6) is coated with a UV-cured anti-slip and wear-resistant coating (19) and is made of neoprene rubber or polyurethane.

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