Electrode terminal for a superconducting charging cable

Abstract

This invention discloses a superconducting charging cable electrode terminal, mainly addressing the problems of low DC charging power and slow speed in existing electric vehicles. It includes: a current lead connection structure (1), a liquid nitrogen path (2), and a terminal frame (3). One end of the current lead connection structure is connected to an external load, and the other end is connected to the terminal frame, allowing the inner and outer current leads to be independently connected to the inner and outer superconducting conductor layers, respectively, thus realizing the function of using a superconducting cable as a high-power DC charging current-carrying cable. One end of the liquid nitrogen path is connected to the terminal frame via a sealed tapered thread, and the other end is connected to the terminal frame via a sealed pipe thread, enabling the return flow of liquid nitrogen from the inner to the outer liquid nitrogen channel. This invention has a compact structure, achieving miniaturization of superconducting power equipment, and provides high DC charging power and fast charging speed, making it suitable for high-power DC charging of electrical loads.

Description

Technical Field

[0001] This invention belongs to the field of superconducting power technology, specifically relating to an electrode terminal that can be used for high-power DC charging of electrical loads. Background Technology

[0002] With the rapid increase in the critical transition temperature of high-temperature superconducting materials in recent years, the application of high-temperature superconducting cables based on high-temperature superconducting tapes has gradually matured. Compared with traditional conventional cables, high-temperature superconducting DC cables have excellent performance in terms of strong current carrying capacity, high energy density, and high transmission power. To achieve cooling and power supply in superconducting cables, the terminal structure of superconducting cables needs to integrate functions such as liquid nitrogen cooling circulation loops and current lead power supply loops.

[0003] Existing high-temperature superconducting DC cables typically only allow for unidirectional current carrying and are used only as high-power current-carrying cables. With the rapid development of the new energy power industry, in some emerging fields, such as the fast charging of electric vehicles, if superconducting cables are used as current-carrying cables for DC charging, traditional high-temperature superconducting DC transmission cables can no longer meet their service requirements. At the same time, traditional high-temperature superconducting DC transmission cables usually require cable terminals at liquid nitrogen inlet and outlet, which are not only structurally complex and redundant but also occupy a large area, making them unsuitable for the application scenarios of DC fast charging for electric vehicles.

[0004] Patent document CN201510422896.7 discloses a "low-temperature insulated high-temperature superconducting cable high-voltage terminal," which includes a current lead, a liquid nitrogen circulation path encased inside a low-temperature Dewar, and a thermal insulation structure. The shielding layer current lead outlet is vertically mounted on the upper surface of the low-temperature Dewar. One end of the current lead is connected to an external power grid, and the other end extends into the terminal structure to connect to the end of the superconducting cable. The current lead inside the terminal is immersed in liquid nitrogen inside the low-temperature Dewar. The low-temperature Dewar is cylindrical and placed horizontally, and its internal liquid nitrogen circulation path connects the liquid nitrogen path of the cable body with the external liquid nitrogen supply path. A thermal insulation support is vertically welded to the low-temperature Dewar. An operating hole is located on the side wall of the low-temperature Dewar, and a evacuation port for the thermal insulation interlayer is located at one end of the low-temperature Dewar and is arranged horizontally.

[0005] US Patent 20080119362 discloses a "cryogenic device for superconducting equipment," which is a terminal structure for realizing the mechanical and electrical connection between a superconducting cable and an external power grid. The terminal includes a current lead interface, a liquid nitrogen channel, and an insulation structure. The terminal consists of two layers: an outer insulating shell that primarily provides mechanical support; current leads extend through the upper interface of the terminal, connecting the external power grid to the end of the superconducting cable; and an inner liquid nitrogen channel that encloses the end of the superconducting cable and the current leads, immersing them in liquid nitrogen. A vacuum insulation interlayer is provided between the outer and inner liquid nitrogen containers to achieve a temperature transition from the interior of the terminal to room temperature.

[0006] The current leads in the aforementioned terminal structure only provide an electrical connection between the superconducting cable body and the external power grid, and can only allow unidirectional current inflow or outflow. They cannot enable high-power charging of electrical loads via the superconducting cable. Furthermore, its liquid nitrogen circulation path only connects the liquid nitrogen channel within the cable body to the external liquid nitrogen channel of the terminal, and cannot achieve unilateral return flow of liquid nitrogen at the terminal. This results in a large footprint and a complex structure. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of the prior art by providing an electrode terminal for a superconducting charging cable, which simplifies the structure, enables superconducting DC charging through a bipolar DC charging circuit, and achieves unilateral reflux of liquid nitrogen circulation in the superconducting cable through a liquid nitrogen reflux pipe.

[0008] The technical solution of this invention is implemented as follows:

[0009] A superconducting charging cable electrode terminal includes: a current lead connection structure 1, a liquid nitrogen passage 2, and a terminal frame 3, characterized in that:

[0010] The current lead connection structure 1 uses two independent electrode bus rings to achieve bidirectional current transmission of the superconducting cable, so as to realize bidirectional high-power DC fast charging of the electrical load through the superconducting cable.

[0011] The liquid nitrogen passage 2 adopts a liquid nitrogen circulation return path composed of an outflow pipe and a return pipe to realize the single-sided return of liquid nitrogen circulation in the superconducting cable, thereby miniaturizing the liquid nitrogen circulation component and saving energy.

[0012] The terminal frame 3 adopts a flange connection structure to reduce the terminal's footprint and facilitate maintenance.

[0013] Furthermore, the current lead connection structure 1 includes an inner electrode bus ring 11, an outer electrode bus ring 12, an inner superconducting conductor layer 13 of the superconducting cable, an inner current lead 14, an outer superconducting conductor layer 15, and an outer current lead 16. One side of the inner electrode bus ring 11 is directly connected to the outer superconducting conductor layer 13 of the superconducting cable, and the other side is connected to the external charging load through the inner current lead 14. One side of the outer electrode bus ring 12 is directly connected to the outer superconducting conductor layer 15, and the other side is connected to the external charging load through the outer current lead 16. The inner electrode bus ring 11 and the outer electrode bus ring 12 are insulated from each other.

[0014] Furthermore, the liquid nitrogen passage 2 includes a bellows compensator 21, a return tee 22, a liquid nitrogen outlet pipe 23, a liquid nitrogen return pipe 24, an inner liquid nitrogen channel 25, an outer liquid nitrogen channel 26, a sealing pipe joint 27, and a return pipe joint 28; the middle inlet of the return tee 22 is connected to the terminal frame 3, and the two outlets are respectively connected to the liquid nitrogen outlet pipe 23; the liquid nitrogen outlet pipe 23 is connected to the liquid nitrogen return pipe 24 through the sealing pipe joint 27; the liquid nitrogen return pipe 24 is connected to the terminal frame 3 through the return pipe joint 28.

[0015] Furthermore, the terminal frame 3 includes an outer liquid nitrogen bellows flange 31, a liquid nitrogen reflux flange 32, an inner liquid nitrogen bellows flange 33, a liquid nitrogen outlet flange 34, an outer liquid nitrogen bellows 35, a sealing ring retainer 36, and an inner liquid nitrogen bellows 38; one end of the outer liquid nitrogen bellows flange 31 is connected to the outer liquid nitrogen bellows 35, and the other end is connected to the liquid nitrogen reflux flange 32, and the other end of the liquid nitrogen reflux flange 32 is connected to the inner liquid nitrogen bellows 38 through the sealing ring retainer 36; one end of the liquid nitrogen outlet flange 34 is connected to the reflux tee 22, and the other end is connected to the bellows compensator 21, the other end of the bellows compensator 21 is connected to the inner liquid nitrogen bellows flange 33, and the other end of the inner liquid nitrogen bellows flange 33 is connected to the inner liquid nitrogen bellows 38.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. This invention connects two electrode bus rings independently to the charging load and the superconducting cable conductor layer, and uses them as the positive and negative poles of the cable for independent current flow, enabling traditional superconducting power transmission cables to be used for high-power fast charging of loads, greatly expanding the application scenarios of superconducting cables.

[0018] 2. By using a liquid nitrogen return pipe to form a liquid nitrogen circulation path, this invention can connect the inner and outer liquid nitrogen channels of the cable, enabling the return of liquid nitrogen at the electrode terminal. There is no need to arrange additional liquid nitrogen inlets and outlets at the electrode terminal; the liquid nitrogen inlet and outlet only need to be arranged on the same side of the superconducting cable. At the same time, it can realize the miniaturization of superconducting power equipment and make the cable terminal structure more compact.

[0019] 3. By using a flange connection assembly as the terminal skeleton and setting sealing measures at the assembly connection, this invention can provide support for the cable body while achieving a sealed connection between the liquid nitrogen circulation path and the cable body. At the same time, the use of a flange connection assembly to form the terminal skeleton can significantly reduce the footprint of the electrode terminal, simplify the manufacturing process, and make the disassembly, maintenance, and repair of the cable terminal more convenient. Attached Figure Description

[0020] Figure 1 This is an overall structural diagram of the present invention;

[0021] Figure 2 yes Figure 1 Cross-sectional view;

[0022] Figure 3 yes Figure 1 Top view of the structure;

[0023] Figure 4 yes Figure 3 Top view of the cross section;

[0024] Figure 5 This is an overall structural diagram of the electrode portion in this invention;

[0025] Figure 6 yes Figure 5 Cross-sectional view. Detailed Implementation

[0026] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0027] Reference Figure 1 , Figure 2 , Figure 3 and Figure 4 The electrode terminal designed in this example includes: a current lead connection structure 1, a liquid nitrogen passage 2, and a terminal frame 3. One end of the current lead connection structure 1 is connected to an external load, and the other end is connected to the terminal frame 3; one end of the liquid nitrogen passage 2 is connected to the terminal frame 3 through a sealing tapered thread, and the other end is connected to the terminal frame 3 through a sealing pipe thread.

[0028] The liquid nitrogen passage 2, used to connect the inner and outer liquid nitrogen channels, includes a bellows compensator 21, a return tee 22, a liquid nitrogen outlet pipe 23, a liquid nitrogen return pipe 24, an inner liquid nitrogen channel 25, an outer liquid nitrogen channel 26, a sealing pipe joint 27, and a return pipe joint 28. The return tee 22 is connected to the liquid nitrogen outlet pipe 23 via a sealing pipe thread. One end of the liquid nitrogen outlet pipe 23 is connected to the sealing pipe joint 27 via a sealing pipe thread, and the other end of the sealing pipe joint 27 is connected to the liquid nitrogen return pipe 24 via a sealing pipe thread. The other end of the liquid nitrogen return pipe 24 is connected to the return pipe joint 28 via a sealing pipe thread. After installation, the liquid nitrogen circulation passage needs to undergo a sealing performance test, namely, verifying the pressure resistance of the liquid nitrogen circulation loop through an internal pressure holding test and verifying the good sealing of the pipe through a helium mass spectrometer leak detector.

[0029] In this embodiment, the return tee 22 is selected, but is not limited to, GB / T 5635-2008 flared tapered thread tee pipe fitting type A, model A18 / NPT1 / 2; the liquid nitrogen outlet pipe 23 and the liquid nitrogen return pipe 24 are both selected, but are not limited to, stainless steel pipes, and both need to be machined with sealing pipe threads at both ends; the sealing pipe fitting 27 and the return pipe fitting 28 are selected, but are not limited to, GB / T 32294-2015 welding union fitting, model SUN20; the bellows compensator 21 is selected, but is not limited to, GB / T 12777-2019 single axial type expansion joint, model DN40, and is lined with polytetrafluoroethylene coating inside; by using the bellows compensator 21 as part of the liquid nitrogen passage, the axial expansion and contraction deformation caused by the large temperature difference can be effectively compensated.

[0030] During operation, liquid nitrogen used to cool the superconducting cable flows in from the inner liquid nitrogen channel 25, passes sequentially through the corrugated compensator 21, the return tee 22, the liquid nitrogen outlet pipe 23, and the liquid nitrogen return pipe 24, and finally flows out from the outer liquid nitrogen channel 26, realizing a complete one-sided liquid nitrogen return process.

[0031] The terminal frame 3 is used to connect the superconducting cable body and the liquid nitrogen channel and to support the cable. It includes an outer liquid nitrogen bellows flange 31, a liquid nitrogen return flange 32, an inner liquid nitrogen bellows flange 33, a liquid nitrogen outlet flange 34, an outer liquid nitrogen bellows 35, a sealing ring retaining ring 36, and an inner liquid nitrogen bellows 38. One end of the outer liquid nitrogen bellows flange 31 is sealed and welded to the outer liquid nitrogen bellows 35, and the other end is fastened to the liquid nitrogen return flange 32 by bolts. One end of the liquid nitrogen outlet flange 34 is sealed and connected to the return tee 22 by a tapered thread, and the other end is fastened to the bellows compensator 21 by bolts. One end of the inner liquid nitrogen bellows flange 33 is fastened to the bellows compensator 21 by bolts, and the other end is sealed and welded to the inner liquid nitrogen bellows 38. The liquid nitrogen return flange 32 is sealed and connected to the return pipe joint 28 in the liquid nitrogen passage 2 through its side threaded process hole. When connecting the inner liquid nitrogen bellows flange 33, the liquid nitrogen outlet flange 34 and the bellows compensator 21, rubber sealing rings need to be placed on their contact surfaces and coated with vacuum sealing grease. The flange connection is then secured by bolts under pressure to ensure its sealing performance.

[0032] In this embodiment, the inner liquid nitrogen bellows flange 33 is selected, but is not limited to, the GB / T 9115-2010 flat-face welded steel pipe flange, model DN25-PN40; the liquid nitrogen outlet flange 34 is selected, but is not limited to, the GB / T 9115-2010 flat-face welded steel pipe flange, model DN25-PN40, as a basic component. The large diameter end remains unchanged, while the small diameter end needs to be machined with a matching sealing tapered thread according to the sealing tapered thread size of the return tee 22; the outer liquid nitrogen bellows flange 31 is selected, but is not limited to, the GB / T 9115-2010 flat-face welded steel pipe flange, model DN65-PN40; the liquid nitrogen return flange 32 is selected, but is not limited to, the GB / T For the 9115-2010 flat butt welded steel pipe flange, model DN65-PN40, the large diameter end remains unchanged, while the small diameter end needs to be machined with sealing pipe thread process holes according to the size of the sealing ring retaining ring 36; at the same time, matching sealing pipe thread process holes need to be machined on the side of the liquid nitrogen reflux flange 32 according to the size of the reflux pipe connector 28 and the current lead plug 310, respectively.

[0033] In this embodiment, a rubber sealing ring 37 needs to be arranged at the small diameter end of the liquid nitrogen reflux flange 32 and cooperate with the sealing ring retainer 36 to achieve a seal. The rubber sealing ring 37 is selected, but not limited to, the mountain-shaped bidirectional sealing rubber sealing ring of GB / T 10708.2-2000, model 32×22×12.5. Its size needs to be selected according to the outer diameter of the inner liquid nitrogen bellows 38. To ensure good sealing performance, the rubber sealing ring 37 and the inner liquid nitrogen bellows 38 should form an interference fit. The sealing ring retainer 36 is made of, but not limited to, 304 stainless steel. Its inner diameter should be selected according to the outer diameter of the inner liquid nitrogen bellows 38. The small diameter connection end of the sealing ring retainer 36 needs to be machined with a corresponding sealing pipe thread according to the thread size of the small diameter end of the liquid nitrogen reflux flange 32. The sealing at the connection between the liquid nitrogen reflux flange 32 and the sealing ring retainer 36 is achieved through threaded connection. At the same time, the sealing ring retainer 36 plays a role in tightening and limiting the rubber sealing ring 37.

[0034] Reference Figure 4 , Figure 5 ,and Figure 6 The current lead connection structure 1 is used to realize the electrical connection between the external load and the superconducting cable body. It includes an inner electrode bus ring 11, an outer electrode bus ring 12, an inner superconducting conductor layer 13 of the superconducting cable, an inner current lead 14, an outer superconducting conductor layer 15, and an outer current lead 16. One side of the inner electrode bus ring 11 is soldered to the outer superconducting conductor layer 13 of the superconducting cable through low-temperature soldering, and the other side is connected to the external charging load through the inner current lead 14. One side of the outer electrode bus ring 12 is soldered to the outer superconducting conductor layer 15 through low-temperature soldering, and the other side is connected to the external charging load through the outer current lead 16.

[0035] The inner electrode bus ring 11 and the outer electrode bus ring 12 are welded on the inner superconducting conductor layer 13 and the outer superconducting conductor layer 15, respectively. During the manufacturing of the superconducting cable electrode side, a stepped shaft structure with a width of 40-60mm needs to be reserved between each layer. The inner electrode bus ring 11 and the outer electrode bus ring 12 are welded on the reserved inner superconducting conductor layer 13 and the outer superconducting conductor layer 15, respectively. During welding, it is necessary to ensure that the inner electrode bus ring 11 and the outer electrode bus ring 12 are in full and dense contact with each superconducting strip of the inner superconducting conductor layer 13 and the outer superconducting conductor layer 15, respectively, to minimize the contact resistance. Meanwhile, process holes are opened on the sides of both the inner electrode busbar 11 and the outer electrode busbar 12. The dimensions of the process holes are determined according to the dimensions of the inner current lead 14 and the outer current lead 16, respectively. The inner current lead 14 and the outer current lead 16 pass through the process holes on the side of the liquid nitrogen return flange 32 in the terminal frame 3 and are connected to the inner electrode busbar 11 and the outer electrode busbar 12, respectively, by bolts and fasteners. It is necessary to ensure that the inner current lead 14 and the outer current lead 16 are insulated from the liquid nitrogen return flange 32. Current lead sealing rings 39 are provided at the contact process holes between the inner current lead 14 and the outer current lead 16 and the liquid nitrogen return flange 32 in the terminal frame 3 to ensure sealing performance. The current lead sealing rings 39 should form an interference fit with the inner current lead 14 and the outer current lead 16, and are limited and tightened by current lead plugs 310.

[0036] All threaded connections must be wrapped with PTFE tape and coated with vacuum sealant to ensure a proper seal.

[0037] In this example, all insulating materials selected, but not limited to, multilayer polypropylene laminated paper, are provided with an insulation strength greater than 10kV in ultra-low temperature environments.

[0038] In this example, the current lead sealing ring 39 is selected, but is not limited to, the mountain-shaped bidirectional sealing rubber sealing ring of GB / T 10708.2-2000, model 25×15×12.5; the current lead plug 310 is made of 304 stainless steel, and its dimensions are selected with reference to the process hole dimensions on the side of the liquid nitrogen reflux flange 32. The sealing connection between the current lead plug 310 and the liquid nitrogen reflux flange 32 is achieved through the sealing pipe thread. The inner electrode bus ring 11 and the outer electrode bus ring 12 are made of, but are not limited to, low-resistance materials such as high-purity copper; the inner current lead 14 and the outer current lead 16 are made of, but are not limited to, rigid copper current leads or flexible copper braided tape.

[0039] The working principle of this example is as follows:

[0040] Liquid nitrogen, used to cool the superconducting cable, flows in from the inner liquid nitrogen channel 25. The liquid nitrogen flowing through the inner liquid nitrogen channel 25 is used to cool the inner superconducting conductor layer 13. The liquid nitrogen passes sequentially through the bellows compensator 21, the return tee 22, the liquid nitrogen outlet pipe 23, and the liquid nitrogen return pipe 24, before flowing back into the liquid nitrogen return flange 32. The liquid nitrogen returning to the liquid nitrogen return flange 32 cools the inner electrode busbar 11 and the outer electrode busbar 12, ensuring that the heat generated by the electrodes during energization does not cause the cable to lose superconductivity. The liquid nitrogen ultimately flows out from the outer... Liquid nitrogen flows out through the outer liquid nitrogen channel 26 and is used to cool the outer superconducting conductor layer 15. When the temperature of the inner superconducting conductor layer 13 and the outer superconducting conductor layer 15 is lower than the critical transition temperature of the superconducting material, the superconducting cable enters a stable and unobstructed current-carrying working state. After the cable enters the working state, the inner current lead 14 is connected to the positive terminal of the charging load, and the outer current lead 16 is connected to the negative terminal of the charging load. After confirming that the connection is secure, power is turned on to realize high-power DC charging of the load through the superconducting cable.

Claims

1. A superconducting charging cable electrode terminal, comprising: The current lead connection structure (1), liquid nitrogen passage (2), and terminal frame (3) are characterized by: The current lead connection structure (1) uses two independent electrode bus rings to realize the bidirectional high-power DC charging function of the superconducting cable, so as to realize the bidirectional high-power DC fast charging of the electrical load through the superconducting cable. The liquid nitrogen passage (2) adopts a liquid nitrogen circulation return path composed of an outlet pipe and a return pipe to realize the single-sided return of liquid nitrogen circulation in the superconducting cable, thereby miniaturizing the liquid nitrogen circulation components and saving energy. The liquid nitrogen passage (2) includes a bellows compensator (21), a return tee (22), a liquid nitrogen outlet pipe (23), a liquid nitrogen return pipe (24), an inner liquid nitrogen channel (25), an outer liquid nitrogen channel (26), a sealing pipe joint (27), and a return pipe joint (28). The middle inlet of the return tee (22) is connected to the terminal frame (3), and the outlets at both ends are connected to the liquid nitrogen outlet pipe (23). The liquid nitrogen outlet pipe (23) is connected to the liquid nitrogen return pipe (24) through the sealing pipe joint (27). The liquid nitrogen return pipe (24) is connected to the terminal frame (3) through the return pipe joint (28). The terminal frame (3) adopts a flange connection structure to reduce the terminal's footprint and facilitate maintenance. The terminal frame (3) includes an outer liquid nitrogen bellows flange (31), a liquid nitrogen reflux flange (32), an inner liquid nitrogen bellows flange (33), a liquid nitrogen outlet flange (34), an outer liquid nitrogen bellows (35), a sealing ring (36), and an inner liquid nitrogen bellows (38). One end of the outer liquid nitrogen bellows flange (31) is connected to the outer liquid nitrogen bellows (35), and the other end... One end is connected to the liquid nitrogen reflux flange (32), and the other end of the liquid nitrogen reflux flange (32) is connected to the inner liquid nitrogen bellows (38) through the sealing ring retainer (36); one end of the liquid nitrogen outlet flange (34) is connected to the reflux tee (22), and the other end is connected to the bellows compensator (21), the other end of the bellows compensator (21) is connected to the inner liquid nitrogen bellows flange (33), and the other end of the inner liquid nitrogen bellows flange (33) is connected to the inner liquid nitrogen bellows (38).

2. The superconducting charging cable electrode terminal according to claim 1, characterized in that, The current lead connection structure (1) includes an inner electrode bus ring (11), an outer electrode bus ring (12), an inner superconducting conductor layer (13) of the superconducting cable, an inner current lead (14), an outer superconducting conductor layer (15), and an outer current lead (16). One side of the inner electrode bus ring (11) is directly connected to the outer superconducting conductor layer (13) of the superconducting cable, and the other side is connected to the external charging load through the inner current lead (14). One side of the outer electrode bus ring (12) is directly connected to the outer superconducting conductor layer (15), and the other side is connected to the external charging load through the outer current lead (16). The inner electrode bus ring (11) and the outer electrode bus ring (12) are insulated from each other.

3. The superconducting charging cable electrode terminal according to claim 2, characterized in that, The inner electrode bus ring (11) is insulated from the outer electrode bus ring (12), and the inner current lead (14) and the outer current lead (16) are insulated from the liquid nitrogen return flange (32) in the terminal frame (3), respectively. The inner current lead (14), the inner electrode bus ring (11), and the inner superconducting conductor layer (13) constitute the positive electrode of the charging circuit. The outer current lead (16), the outer electrode bus ring (12), and the outer superconducting conductor layer (15) constitute the negative electrode of the charging circuit. The positive and negative electrodes are independent of each other and insulated from each other, and together they constitute a complete charging circuit.

4. The superconducting charging cable electrode terminal according to claim 1, characterized in that, Liquid nitrogen flows in from the inner liquid nitrogen channel (25), passes through the bellows compensator (21), the return tee (22), the liquid nitrogen outlet pipe (23), and the liquid nitrogen return pipe (24) in sequence, and finally flows out from the outer liquid nitrogen channel (26), realizing the unilateral return of liquid nitrogen at the electrode terminal.

5. The superconducting charging cable electrode terminal according to claim 1, characterized in that, The inner liquid nitrogen bellows (38) is sealed and welded to the inner liquid nitrogen bellows flange (33); the outer liquid nitrogen bellows flange (31) is sealed and welded to the outer liquid nitrogen bellows (35); the liquid nitrogen return flange (32) is fastened to the outer liquid nitrogen bellows flange (31) by bolts; the inner liquid nitrogen bellows flange (33) and the liquid nitrogen outflow flange (34) are all fastened to the bellows compensator (21) in the liquid nitrogen passage (2) by bolts.

6. The superconducting charging cable electrode terminal according to claim 1, characterized in that, A rubber sealing ring (37) is provided at the contact point between the liquid nitrogen reflux flange (32) and the inner liquid nitrogen bellows (38). The rubber sealing ring (37) is limited and fixed by a sealing ring retainer (36) on the outside. The sealing ring retainer (36) and the liquid nitrogen reflux flange (32) are connected by a pipe thread to ensure that the outer liquid nitrogen channel (26) in the liquid nitrogen passage (2) is sealed.

7. The superconducting charging cable electrode terminal according to claim 1, characterized in that, The liquid nitrogen reflux flange (32) is provided with a current lead sealing ring (39) at the contact points with the inner current lead (14) and the outer current lead (16) in the current lead connection structure (1). The current lead sealing ring (39) is limited and fixed by the current lead plug (310). The current lead plug (310) and the liquid nitrogen reflux flange (32) are connected by a pipe thread seal to ensure the sealing of the outer liquid nitrogen channel (26) in the liquid nitrogen passage (2).

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