A diffusion bonding apparatus for a rare earth barium copper oxide coated conductor

Abstract

The application discloses a diffusion connection device for a rare earth barium copper oxygen coating conductor and relates to the technical field of superconducting electrical engineering. The device comprises a bottom plate, electrodes, a base, a heating assembly, a cover plate, a pressing block and a thermocouple. The base is installed on the bottom plate, and the base is provided with a groove for installing the heating assembly. The heating assembly comprises two heating units symmetrically arranged in an up-down direction. The heating unit comprises a heat insulation bottom plate, a heating sheet and a heat insulation cover plate which are sequentially stacked. The heat insulation cover plate is embedded with a heat spreading sheet. The electrodes are connected with the two heating sheets for heating the heating sheets. The two heating units are used for placing the rare earth barium copper oxygen coating conductor. The thermocouple is in contact with the two heat spreading sheets. The cover plate is provided with a protrusion at the bottom end, which is matched with the groove. The lower surface of the protrusion is provided with a heating groove. The cover plate is provided with a through hole matched with the pressing block. The application can realize a rapid and accurate temperature control process, the temperature field of the heating area is uniform, the negative influence of the high-temperature process on the superconducting performance of the coating conductor is relieved, and the joint resistance is reduced.

Description

Technical Field

[0001] This invention relates to the field of superconducting electrical technology, and in particular to a diffusion connection device for a rare-earth barium copper oxide coated conductor. Background Technology

[0002] Based on rare earth barium copper oxide (REBa2Cu3O) 7-x REBCO (Rare Earth Elements such as Y and Gd) coated conductors (also known as second-generation high-temperature superconducting tapes or REBCO tapes) possess advantages such as high critical transition temperature, strong current carrying capacity, and excellent mechanical properties, making them promising for applications in power, energy, strong magnetic fields, and magnetic levitation transportation. Commercially available REBCO coated conductors are typically in lengths of tens to hundreds of meters. Therefore, in practical applications such as winding magnets and developing cables, it is inevitable to connect the tapes to extend their length.

[0003] REBCO coated conductors are generally composed of a metal alloy base tape, a buffer layer, a REBCO superconducting layer, a silver layer, and a copper layer, sequentially composited. Removing the copper layer from the REBCO tape and directly using the silver layer for diffusion bonding to form a joint can achieve low resistance (<10 nΩ·cm). 2 The silver diffusion joint of the coated conductor requires annealing of the REBCO superconducting layer in oxygen at 350–550°C to maintain its superconducting properties. Therefore, traditional silver diffusion requires temperatures within this range. However, the original silver layer of the coated conductor is not perfectly smooth, making complete bonding difficult within this temperature range. High porosity at the interface leads to high joint resistivity. Therefore, further increasing the temperature (>550°C) can promote softening and full contact of the silver layer to form a complete connection, reducing interface porosity and thus lowering joint resistivity. However, prolonged high-temperature heat treatment will cause the REBCO superconducting layer to lose oxygen, reducing its superconducting properties and consequently lowering the critical current and increasing joint resistance. Therefore, rapid heating and cooling processes are needed to shorten the heat treatment time in the high-temperature region. Existing devices typically have large heat capacities, resulting in slow heating and cooling processes and uneven temperature fields in the heating zone. Further increasing the diffusion heat treatment temperature will cause the REBCO coated conductor to remain in the oxygen-depleted temperature region for an extended period, leading to a decline in joint performance.

[0004] In summary, there is a need for a novel diffusion connection device for REBCO coated conductors that can achieve rapid and precise temperature control, uniform temperature field in the heating area, mitigate the negative impact of high-temperature processes on the superconducting properties of the coated conductors, and reduce joint resistance. Summary of the Invention

[0005] The purpose of this invention is to provide a diffusion connection device for rare earth barium copper oxide coated conductors to solve the problems existing in the prior art. It can achieve a rapid and precise temperature control process, a uniform temperature field in the heating area, mitigate the negative impact of high temperature process on the superconducting performance of the coated conductor, and reduce the joint resistance.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] This invention provides a diffusion connection device for a rare-earth barium copper oxide coated conductor, comprising a base plate, electrodes, a base, a heating assembly, a cover plate, a pressure block, and a thermocouple. The base is mounted on the base plate and has a groove for mounting the heating assembly. The heating assembly includes two heating units symmetrically arranged vertically. Each heating unit includes a heat-insulating base plate, a heating element, and a heat-insulating cover plate stacked sequentially. A heat-spreading plate is embedded in the heat-insulating cover plate and contacts the heating area of ​​the heating element. The heat-spreading plate is made of thermally conductive ceramic material. The electrodes are connected to the two heating elements for heating them. A rare-earth barium copper oxide coated conductor is placed between the two heating units. The overlapping area of ​​the body is placed between the two heat spreaders and in contact with the two heat spreaders respectively; the thermocouple is in contact with the two heat spreaders and is used to measure the temperature of the heat spreaders; the bottom end of the cover plate is provided with a protrusion that cooperates with the groove, the lower surface of the protrusion is provided with a heating groove, the protrusion is inserted into the groove and pressed on the heating assembly, the heating groove and the space in the groove below it constitute a heating space, the side wall of the heating groove is provided with an air inlet pipe that communicates with the heating space, the cover plate is provided with a through hole that cooperates with the pressure block, the through hole communicates with the heating space, and the pressure block presses down on the upper surface of the heating assembly to pressurize the overlapping area of ​​the rare earth barium copper oxide coated conductor.

[0008] Preferably, each end of the heating component has a positioning block embedded therein, and the positioning block is provided with a conductor positioning groove for assisting the overlapping of rare earth barium copper oxide coated conductors.

[0009] Preferably, the base has positioning grooves on both sides, and the cover plate has positioning protrusions on both sides that respectively cooperate with the positioning grooves.

[0010] Preferably, the base, the cover plate, the pressure block, and the positioning block are made of stainless steel; the bottom plate, the heat-insulating bottom plate, and the heat-insulating cover plate are made of mica.

[0011] Preferably, the heat spreader is made of aluminum nitride ceramic material and has a thickness of 1 mm; the heating element is made of nickel-chromium alloy and has a thickness of 0.05–0.1 mm.

[0012] Preferably, the heating element includes a heating zone, a transition zone, and an electrode zone. Each end of the heating zone is connected to an electrode zone through a transition zone. The electrodes include a first electrode and a second electrode arranged symmetrically. The first electrode and the second electrode have a U-shaped structure. The two ends of the U-shaped opening of the first electrode are respectively connected to two electrode zones on the same side of the heating zone, and the two ends of the U-shaped opening of the second electrode are respectively connected to two electrode zones on the other side of the heating zone.

[0013] Preferably, both the first electrode and the second electrode include a U-shaped bottom electrode, and each of the two ends of the U-shaped opening of the bottom electrode is threaded to an upper electrode, and each of the upper electrodes clamps the respective electrode area between the upper electrode and the bottom electrode.

[0014] Preferably, the width of the heating zone is 5-13 mm, which is greater than the width of the rare earth barium copper oxide coated conductor; the width of the transition zone is half the width of the heating zone; and the width of the electrode zone is 2-3 times the width of the heating zone.

[0015] Preferably, the heat spreader and the heat insulation cover have the same thickness, and the thickness of the heat insulation base plate is 3-5 mm.

[0016] Preferably, a nickel sheet is inserted between the heat spreader and the rare-earth barium copper oxide coated conductor, the width of the nickel sheet being greater than the width of the rare-earth barium copper oxide coated conductor, and the endpoint of the thermocouple is welded to the midpoint of one side of the nickel sheet.

[0017] The present invention achieves the following technical effects compared to the prior art:

[0018] This invention provides a diffusion connection device for rare-earth barium copper oxide coated conductors, enabling silver diffusion connections. The device is compact, incorporating a low-heat-capacity heating element and placing the thermocouple temperature measurement point close to the heating area. This allows for rapid and precise heating and cooling processes, shortening the duration of the high-temperature zone when the heat treatment temperature exceeds the traditional silver diffusion temperature. This mitigates the negative impact of the high-temperature process on the superconducting performance of the rare-earth barium copper oxide coated conductor, reduces joint resistance, and utilizes a thermally conductive ceramic material with extremely high thermal conductivity, resulting in a more uniform temperature field in the heat treatment area.

[0019] Furthermore, the positioning block guides the alignment and overlap of the rare-earth barium copper oxide coated conductors, assisting in the overlapping and fixing of the heating components, making operation more convenient. The heat spreader, being an insulating material, isolates the rare-earth barium copper oxide coated conductors from the heating element's electrical contact. After heat treatment, the conductors are less likely to stick to the heat spreader due to high-temperature diffusion bonding, making it easier to remove the connector. Additionally, the relatively soft texture of the mica plate and nickel sheet allows for more uniform pressure applied to the overlapping area, making it easier to obtain a low-resistivity silver diffusion connector. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the diffusion connection device for the rare earth barium copper oxide coated conductor provided by the present invention.

[0022] Figure 2 A top view of the diffusion connection device for the rare earth barium copper oxide coated conductor provided by the present invention;

[0023] Figure 3 An exploded view of the diffusion connection device for the rare earth barium copper oxide coated conductor provided by the present invention.

[0024] Figure 4 This is a schematic diagram of the cover plate in this invention;

[0025] Figure 5 This is a schematic diagram of the structure of the heating component, the positioning block, and the rare-earth barium copper oxide coated conductor in this invention;

[0026] Figure 6 for Figure 5 Exploded view;

[0027] Figure 7 This is a schematic diagram of the heating unit in this invention;

[0028] Figure 8 This is a schematic diagram of the heating element in this invention;

[0029] Figure 9 The image shows the VI curve of the silver diffusion joint obtained using the device of the present invention.

[0030] In the diagram: 1-Base plate, 2-Electrode, 3-Base, 4-Heating component, 5-Cover plate, 6-Pressure block, 7-Thermocouple, 8-Groove, 9-Heating unit, 10-Insulated base plate, 11-Heating element, 12-Insulated cover plate, 13-Heating plate, 14-Heating zone, 15-Rare earth barium copper oxide coated conductor, 16-Bump, 17-Heating groove, 18-Air inlet pipe, 19-Through hole, 20-Positioning block, 21-Conductor positioning groove, 22-Positioning groove, 23-Positioning bump, 24-Transition zone, 25-Electrode zone, 26-First electrode, 27-Second electrode, 28-Bottom electrode, 29-Upper electrode, 30-Threaded hole, 31-Fixing hole. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The purpose of this invention is to provide a diffusion connection device for rare earth barium copper oxide coated conductors to solve the problems existing in the prior art. It can achieve a rapid and precise temperature control process, a uniform temperature field in the heating area, mitigate the negative impact of high temperature process on the superconducting performance of the coated conductor, and reduce the joint resistance.

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] like Figures 1-8As shown, this embodiment provides a diffusion connection device for a rare earth barium copper oxide coated conductor, including a base plate 1, an electrode 2, a base 3, a heating assembly 4, a cover plate 5, a pressure block 6, and a thermocouple 7. The base 3 is mounted on the base plate 1, and the base 3 has a groove 8 for mounting the heating assembly 4. The heating assembly 4 includes two heating units 9 arranged symmetrically above and below each other. The heating unit 9 includes a heat-insulating base plate 10, a heating element 11, and a heat-insulating cover plate 12 stacked sequentially. A heat-spreading plate 13 is embedded in the heat-insulating cover plate 12, and the heat-spreading plate 13 contacts the heating area 14 of the heating element 11. The electrode 2 is connected to the two heating elements 11 for heating the heating elements 11. A rare earth barium copper oxide coated conductor 15 is placed between the two heating units 9, and the rare earth barium copper oxide coated conductor 15 overlaps. The overlapping area is placed between two heat spreaders 13 and in contact with each of the two heat spreaders 13 respectively; the heat spreaders 13 are made of thermally conductive ceramic material; the thermocouple 7 is in contact with the two heat spreaders 13 and is used to measure the temperature of the heat spreaders 13; the bottom end of the cover plate 5 is provided with a protrusion 16 that cooperates with the groove 8, the lower surface of the protrusion 16 is provided with a heating groove 17, the protrusion 16 is inserted into the groove 8 and pressed on the heating component 4, the space in the heating groove 17 and the groove 8 below it constitutes the heating space, the side wall of the heating groove 17 is provided with an air inlet pipe 18 that communicates with the heating space, the cover plate 5 is provided with a through hole 19 that cooperates with the pressure block 6, the through hole 19 communicates with the heating space, and the pressure block 6 presses down on the upper surface of the heating component 4 to pressurize the overlapping area of ​​the rare earth barium copper oxide coated conductor 15.

[0035] Oxygen can be introduced into the heating space through the air inlet pipe 18 to provide an oxygen atmosphere for the rare earth barium copper oxide coated conductor 15. The heating component 4 can conveniently control the heating of the overlapping area of ​​the rare earth barium copper oxide coated conductor 15. With the heating element 11 of low heat capacity and the thermocouple 7 temperature measuring point close to the heating area, a rapid and accurate heating and cooling process can be achieved. When the heat treatment temperature is higher than the traditional silver diffusion temperature, the duration of the high temperature zone is shortened, the negative impact of the high temperature process on the superconducting performance of the rare earth barium copper oxide coated conductor is mitigated, and the joint resistance is reduced. In addition, the heat spreader 13 is made of thermally conductive ceramic material with extremely high thermal conductivity, making the temperature field of the heat treatment area more uniform.

[0036] In this embodiment, positioning blocks 20 are embedded in both ends of the heating component 4. The positioning blocks 20 are provided with conductor positioning grooves 21 for assisting the overlapping of the rare earth barium copper oxide coated conductors 15. The positioning blocks 20 guide the ends of the rare earth barium copper oxide coated conductors 15 to align and overlap, assisting in the overlapping of the rare earth barium copper oxide coated conductors 15 and fixing the heating component, making the operation more convenient.

[0037] In this embodiment, the base 3 has positioning grooves 22 on both sides, and the cover plate 5 has positioning protrusions 23 on both sides that respectively cooperate with the positioning grooves 22. Specifically, each side of the cover plate 5 has two positioning protrusions 23, and the distance between the outer edges of the two positioning protrusions 23 on the same side is equal to the width of the positioning groove 22, thereby enabling convenient and quick installation and positioning of the cover plate 5 and the base 3.

[0038] In this embodiment, the base 3, cover plate 5, pressure block 6, and positioning block 20 are made of stainless steel; the bottom plate 1, heat-insulating bottom plate 10, and heat-insulating cover plate 12 are made of mica. In some embodiments, a nickel sheet is inserted between the heat spreader 13 and the rare-earth barium copper oxide coated conductor 15. The width of the nickel sheet is greater than the width of the rare-earth barium copper oxide coated conductor 15, and the endpoint of the thermocouple 7 is welded to the midpoint of one side of the nickel sheet. The mica sheet and the nickel sheet are relatively soft, which allows the pressure applied by the pressure block 6 to the overlapping area to be more uniform, thereby making it easier to obtain a low-resistivity silver diffusion joint.

[0039] In this embodiment, the heat spreader 13 is made of aluminum nitride ceramic material and has a thickness of 1 mm; the heating element 11 is made of nickel-chromium alloy and has a thickness of 0.05–0.1 mm. The heating element 11 can also be made of oxidation-resistant materials such as stainless steel.

[0040] In this embodiment, the heating element 11 includes a heating area 14, a transition area 24, and an electrode area 25. Each end of the heating area 14 is connected to an electrode area 25 through a transition area 24. The electrode 2 includes a first electrode 26 and a second electrode 27 arranged symmetrically. The first electrode 26 and the second electrode 27 have a U-shaped structure. The two ends of the U-shaped opening of the first electrode 26 are respectively connected to the two electrode areas 25 on the same side of the heating area 14, and the two ends of the U-shaped opening of the second electrode 27 are respectively connected to the two electrode areas 25 on the other side of the heating area 14.

[0041] In this embodiment, both the first electrode 26 and the second electrode 27 include a U-shaped bottom electrode 28. The two ends of the U-shaped opening of the bottom electrode 28 are respectively threaded to an upper electrode 29, and each upper electrode 29 clamps each electrode region 25 between the upper electrode 29 and the bottom electrode 28.

[0042] In this embodiment, the width of the heating zone 14 is 5-13 mm, which is greater than the width of the rare earth barium copper oxide coated conductor 15; the width of the transition zone 24 is half the width of the heating zone 14; and the width of the electrode zone 25 is 2-3 times the width of the heating zone 14.

[0043] In this embodiment, the heat spreader 13 and the heat insulation cover 12 have the same thickness, and the heat insulation base plate 10 has a thickness of 3-5 mm.

[0044] The diffusion connection device using the rare earth barium copper oxide coated conductor of the present invention has the following diffusion connection process:

[0045] Two rare-earth barium copper oxide coated conductors 15 are embedded in the conductor positioning grooves 21 of the positioning block 20 to facilitate the overlap of the ends of the rare-earth barium copper oxide coated conductors 15. Then, the overlapping area is clamped together on both sides by a heat-spreading plate 13, a heat-insulating cover plate 12, a heating plate 11, and a heat-insulating base plate 10 to form a heating assembly 4. At the same time, the endpoint of the thermocouple 7 is inserted and contacts the midpoint of the heat-spreading plate 13. Next, the heating assembly 4 is embedded in the base 3 and fitted together. The cover plate 5 is threaded onto the base 3 through the engagement of the positioning protrusion 23 and the positioning groove 22. The heating assembly 4 is then pressed down into the groove 8 of the base 3. A semi-sealed cavity, i.e., a heating space, is formed; the base 3 and the electrode 2 are installed and fixed on the base plate 1; the exposed electrode area 25 in the heating assembly 4 is clamped by the bottom electrode 28 and the top electrode 29, and fixed to the base plate 1 by bolts; the pressure block 6 passes through the through hole 19 and applies pressure to the overlapping area of ​​the corresponding coated conductor in the heating assembly 4; the current lead is fixed and connected to the heating power supply by the threaded hole 30 on the base plate 1, the fixing hole 31 on the bottom electrode 28 and the bolts; the temperature of the heating zone 14 is controlled by connecting the power supply and the thermocouple 7 with the temperature controller; the gas source is connected to the air inlet pipe 18 to introduce oxygen.

[0046] The present invention will be further described in detail below with reference to specific embodiments.

[0047] (1) Two rare-earth barium copper oxide coated conductors 15 are embedded in the conductor positioning grooves 21 of the positioning block 20 to facilitate the overlap of the ends of the rare-earth barium copper oxide coated conductors 15; the width of the rare-earth barium copper oxide coated conductors 15 is 4mm, the overlap length is 4cm, that is, the joint area is 1.6cm². 2Then, the heating assembly 4 is formed by clamping the two sides of the overlapping area together with the heat spreader 13, the heat insulation cover plate 12, the heating plate 11, and the heat insulation base plate 10. At the same time, the end of the thermocouple 7 is inserted and contacts the midpoint of the heat spreader 13. Next, the heating assembly 4 is embedded into the base 3 and the cover plate 5 is threaded onto the base 3 through the cooperation of the positioning protrusion 23 and the positioning groove 22. The heating assembly 4 is pressed down into the groove 8 of the base 3 to form a semi-sealed cavity, i.e., the heating space. The base 3 and the electrode 2 are installed and fixed to the base plate 1. The electrode area 25 exposed in the heating assembly 4 is clamped by the bottom electrode 28 and the upper electrode 29 and fixed to the base plate 1 with bolts. The pressure block 6 passes through. The through hole 19 applies a pressure of 320 kg to the overlapping area of ​​the corresponding coated conductor in the heating assembly 4. The diffusion connection pressure applied is calculated to be 20 MPa based on the area of ​​the joint. The current lead is fixed and connected to the heating power supply by the threaded hole 30 on the base plate 1, the fixing hole 31 on the bottom electrode 28 and the bolt. The temperature of the heating zone 14 is controlled by connecting the power supply and the thermocouple 7 with a temperature controller. The gas source is connected to the air inlet pipe 18 to introduce oxygen at a flow rate of 200 sccm. The temperature is set to rise to 800°C at 10°C / s and held for 1 min. Then, the temperature is lowered to 450°C at 10°C / s for 2 h of heat treatment. After the heat treatment is completed, the joint is removed after the diffusion connection fixture has cooled to room temperature. Figure 9 The VI curve obtained by the four-lead method for the silver diffusion joint obtained in this embodiment is shown in the figure. The joint resistance is 2nΩ·cm. 2 The critical current is 108A, indicating that a silver diffusion connector with low resistivity and high critical current can be obtained by using the diffusion connection device described in this invention.

[0048] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A diffusion connection device for a rare-earth barium copper oxide coated conductor, characterized in that: The system includes a base plate, electrodes, a base, a heating assembly, a cover plate, a pressure block, and thermocouples. The base is mounted on the base plate and has a groove for mounting the heating assembly. The heating assembly includes two heating units symmetrically arranged vertically. Each heating unit includes a heat-insulating base plate, a heating element, and a heat-insulating cover plate stacked sequentially. A heat-spreading plate is embedded in the heat-insulating cover plate and contacts the heating area of ​​the heating element. The heat-spreading plate is made of thermally conductive ceramic material. The electrodes are connected to the two heating elements for heating them. A rare-earth barium copper oxide coated conductor is placed between the two heating units, with the overlapping area of ​​the rare-earth barium copper oxide coated conductor positioned between the two heating units. The heat spreaders are in contact with each other and with two heat spreaders respectively; the thermocouple is in contact with the two heat spreaders and is used to measure the temperature of the heat spreaders; the bottom end of the cover plate is provided with a protrusion that cooperates with the groove, the lower surface of the protrusion is provided with a heating groove, the protrusion is inserted into the groove and pressed on the heating assembly, the heating groove and the space in the groove below it constitute a heating space, the side wall of the heating groove is provided with an air inlet pipe that communicates with the heating space, the cover plate is provided with a through hole that cooperates with the pressure block, the through hole communicates with the heating space, and the pressure block presses down on the upper surface of the heating assembly to pressurize the overlapping area of ​​the rare earth barium copper oxide coated conductor.

2. The diffusion connection device for rare earth barium copper oxide coated conductors according to claim 1, characterized in that: The heating component has positioning blocks embedded at both ends, and the positioning blocks are provided with conductor positioning grooves for assisting the overlapping of rare earth barium copper oxide coated conductors.

3. The diffusion connection device for rare earth barium copper oxide coated conductors according to claim 1, characterized in that: The base has positioning grooves on both sides, and the cover plate has positioning protrusions on both sides that respectively cooperate with the positioning grooves.

4. The diffusion connection device for rare earth barium copper oxide coated conductors according to claim 2, characterized in that: The base, the cover plate, the pressure block, and the positioning block are made of stainless steel; the bottom plate, the heat-insulating bottom plate, and the heat-insulating cover plate are made of mica.

5. The diffusion connection device for the rare earth barium copper oxide coated conductor according to claim 1, characterized in that: The heat spreader is made of aluminum nitride ceramic material and has a thickness of 1 mm; the heating element is made of nickel-chromium alloy and has a thickness of 0.05–0.1 mm.

6. The diffusion connection device for rare earth barium copper oxide coated conductors according to claim 1, characterized in that: The heating element includes a heating zone, a transition zone, and an electrode zone. Each end of the heating zone is connected to an electrode zone through a transition zone. The electrodes include a first electrode and a second electrode arranged symmetrically. The first electrode and the second electrode have a U-shaped structure. The two ends of the U-shaped opening of the first electrode are respectively connected to two electrode zones on the same side of the heating zone. The two ends of the U-shaped opening of the second electrode are respectively connected to two electrode zones on the other side of the heating zone.

7. The diffusion connection device for a rare earth barium copper oxide coated conductor according to claim 6, characterized in that: Both the first electrode and the second electrode include a U-shaped bottom electrode. The two ends of the U-shaped opening of the bottom electrode are respectively threaded to an upper electrode, and each of the upper electrodes clamps the respective electrode area between the upper electrode and the bottom electrode.

8. The diffusion connection device for rare earth barium copper oxide coated conductors according to claim 6, characterized in that: The width of the heating zone is 5-13 mm, which is greater than the width of the rare earth barium copper oxide coated conductor; the width of the transition zone is half the width of the heating zone; and the width of the electrode zone is 2-3 times the width of the heating zone.

9. The diffusion connection device for the rare earth barium copper oxide coated conductor according to claim 1, characterized in that: The heat spreader and the heat insulation cover have the same thickness, and the heat insulation base plate has a thickness of 3-5 mm.

10. The diffusion connection device for the rare earth barium copper oxide coated conductor according to claim 1, characterized in that: A nickel sheet is inserted between the heat spreader and the rare-earth barium copper oxide coated conductor. The width of the nickel sheet is greater than the width of the rare-earth barium copper oxide coated conductor. The endpoint of the thermocouple is welded to the midpoint of one side of the nickel sheet.

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