A high-strength composite sheath stacked high temperature superconducting conductor structure and a manufacturing process

Abstract

This invention discloses a high-strength composite-clad stacked high-temperature superconducting conductor structure and its fabrication process. The high-temperature superconducting conductor structure includes a superconducting tape, a copper cap, a copper base, and a copper cladding. The superconducting tape is composed of multiple REBCO high-temperature superconducting tapes stacked together to form a rectangular or square cross-section. The copper cap and copper base are used to encapsulate the superconducting tape, which is twisted together and then inserted into the copper cladding. Finally, the superconducting conductor is fabricated by soldering. The fabrication process of this invention includes tape stacking, tape insertion into a slot, conductor twisting, conductor tube reduction, and conductor soldering. This invention has advantages such as high current density, high mechanical strength, simple and reliable fabrication process, and ease of fabricating conductors over 100 meters in length. It can be applied to the field of superconducting magnets for various power equipment and large scientific facilities.

Description

Technical Field

[0001] This invention relates to the field of superconducting magnets for power equipment and large scientific facilities, specifically to a high-strength composite-clad stacked high-temperature superconducting conductor structure and its fabrication process. Background Technology

[0002] Compared to first-generation high-temperature superconducting tapes, second-generation high-temperature superconducting tapes, represented by REBCO, possess higher critical current densities and superior mechanical and electromagnetic properties. After more than a decade of development, their fabrication processes have matured, and they hold broad application prospects in superconducting magnets for large scientific facilities such as superconducting power equipment, nuclear fusion, and strong magnetic fields. Currently, commercially available REBCO high-temperature superconducting tapes have a thickness of approximately 0.1 mm and a width of 2–12 mm. Due to the limited current-carrying capacity of a single superconducting tape, the use of multiple tapes connected in parallel to fabricate cable conductors inevitably presents technical challenges related to twisting and transposition. Therefore, it is necessary to develop new conductor structures and fabrication processes. Summary of the Invention

[0003] To address the aforementioned technical problems, the present invention aims to provide a high-strength composite-clad stacked high-temperature superconducting conductor structure and its fabrication process, thereby achieving high current density, high mechanical strength, simple and reliable fabrication process, and ease of fabricating conductors on the order of hundreds of meters or longer.

[0004] This invention provides the following technical solution:

[0005] A high-strength composite-clad stacked high-temperature superconducting conductor structure is disclosed, comprising a superconducting tape, a copper cap, a copper base, and a copper cladding. The superconducting tape is composed of multiple REBCO high-temperature superconducting tapes stacked together to form a stacked structure with a rectangular or square cross-section. The copper cap and copper base are used to encapsulate the superconducting tape, which are twisted together and inserted into the copper cladding. Finally, the superconducting conductor is fabricated by soldering.

[0006] A fabrication process for a high-strength composite-clad stacked high-temperature superconducting conductor structure, the fabrication process including strip stacking, strip insertion into a groove, conductor twisting, conductor tube reduction, conductor welding, etc.

[0007] This invention also proposes a fabrication process for a high-strength composite-clad stacked high-temperature superconducting conductor, the specific steps of which are as follows:

[0008] Step 1: Arrange multiple REBCO high-temperature superconducting tapes neatly to form a stacked structure with a rectangular or square cross-section;

[0009] Step 2: Place the stacked strip into the copper groove between the copper cap and the copper base to form a block structure with a circular cross-section;

[0010] Step 3: Fix the ends of the block structure and twist it along the center line at a predetermined pitch to obtain the twisted conductor;

[0011] Step 4: Insert the twisted conductor into the copper sheath and reduce the diameter of the copper sheath;

[0012] Step 5: Finally, solder is used to fill the gaps between the superconducting tape and the copper cap and the copper base, between the copper cap and the copper base, and between the bulk structure and the copper sheath, to prepare a robust superconducting conductor.

[0013] Further, step 1 includes:

[0014] The REBCO high-temperature superconducting tape is selected with a thickness of 0.1mm and a width of 3mm or the required size, and is stacked into a stacked structure with a cross-sectional size of 3×3mm. It is tightly wound with copper-clad tape at equal intervals to prevent relative slippage between the tapes.

[0015] Further, step 2 includes:

[0016] The upper copper cover and the copper groove are both 6mm in diameter and are made of oxygen-free copper. The cross-sectional dimensions of the copper groove are 3.2×3mm or the required dimensions to ensure that the superconducting tape can be smoothly inserted and twisted.

[0017] Further, step 3 includes:

[0018] The two ends of the fixed block structure are twisted simultaneously, and the twisting pitch needs to be greater than the critical pitch that the high-temperature superconducting tape can withstand.

[0019] Further, step 4 includes:

[0020] During the diameter reduction process, the stepped copper cap and copper base designed by the copper sheath can be positioned well, reducing the lateral compression of the superconducting tape and maximizing the preservation of the tape's own performance.

[0021] Further, step 5 includes:

[0022] The soldering method involves using a certain pressure to melt the solder and fully fill the gaps inside the high-temperature superconducting stacked conductors. The soldering temperature is controlled below 200°C.

[0023] The advantages of this invention compared to the prior art are as follows:

[0024] 1. Stacked superconducting tapes, through twisting at a certain pitch, effectively reduce their AC losses, increase the critical current, and have the characteristics of high transmission current density.

[0025] 2. The copper sheath added to the outside of the superconducting conductor can better protect the core strip and the copper rod formed by the copper cap and copper base, and the mechanical strength of the conductor is improved by soldering.

[0026] 3. The introduction of copper rods increases the proportion of copper metal in the conductor, which can serve as a current shunting function. In addition, it can transfer the heat generated by the superconducting tape during the energization process to the cooling medium, thereby enhancing the thermal stability of the conductor.

[0027] 4. The designed stepped copper cap and copper base can be well positioned, which facilitates subsequent conductor tube reduction and welding processes, reduces the lateral compression of the superconducting strip by the copper sheath during the reduction process, and maximizes the preservation of the strip's own performance.

[0028] 5. The fabrication process of superconducting conductors is simple and reliable, making them more suitable for large-scale industrial production and the fabrication of conductors on the order of hundreds of meters or longer;

[0029] 6. This high-strength composite sheathed stacked high-temperature superconducting conductor structure can also be used as a sub-cable of superconducting cables. It is suitable for large armored cables for high fields or Rutherford cable-type superconducting magnets and has strong scalability. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a high-strength composite-clad stacked high-temperature superconducting conductor according to the present invention;

[0031] Figure 2 This is a schematic cross-sectional view of a high-strength composite-clad stacked high-temperature superconducting conductor according to the present invention;

[0032] Figure 3 This is a schematic diagram illustrating the fabrication process of a high-strength composite-clad stacked high-temperature superconducting conductor according to the present invention.

[0033] In the diagram: 1-copper sheath, 2-copper cap, 3-superconducting tape, 4-copper base. Detailed Implementation

[0034] 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 a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] like Figure 1 and 2As shown, this invention discloses a high-strength composite-clad stacked high-temperature superconducting conductor structure and its fabrication process. The high-temperature superconducting conductor structure includes a superconducting tape 3, a copper cap 2, a copper base 4, and a copper cladding 1. The superconducting tape 3 is formed by stacking multiple REBCO high-temperature superconducting tapes to form a stacked structure with a rectangular or square cross-section. The copper cap 2 and the copper base 4 are used to encapsulate the superconducting tape 3. After being twisted together, they are inserted into the copper cladding 1, and finally, a superconducting conductor is fabricated by soldering.

[0036] like Figure 3 As shown, the fabrication process of a high-strength composite-clad stacked high-temperature superconducting conductor includes strip stacking, strip insertion into a groove, conductor twisting, conductor tube reduction, and conductor welding.

[0037] The specific process flow is as follows:

[0038] Step 1, Strip Stacking: Select REBCO high-temperature superconducting strips with a thickness of 0.1mm and a width of 3mm or the required size, and stack them neatly into a stacked structure with a cross-sectional size of 3×3mm. Tightly wrap them with copper-clad tape with a thickness of 0.05mm and a width of 4mm at a pitch of 20mm to prevent relative slippage between the superconducting strips 3.

[0039] Step 2, Strip insertion: Place the stacked strip into the copper groove between the copper cap 2 and the copper base 4 to form a block structure with a circular cross-section. The copper cap 2 and the copper base 4 have a diameter of 6mm. Both are made of oxygen-free copper. The cross-sectional dimensions of the copper groove are 3.2×3mm or the required dimensions to ensure that the superconducting strip 3 can be smoothly inserted and twisted.

[0040] Step 3, Conductor Twisting: Fix both ends of the block structure and twist it along the center line. The twisting pitch needs to be greater than the critical pitch that the high-temperature superconducting tape 3 can withstand.

[0041] Step 4, Conductor tube reduction: Insert the twisted conductor into the copper sheath 1 and reduce the diameter of the copper sheath 1 appropriately. The designed stepped copper cap 2 and copper base 4 can be positioned well, which facilitates the conductor tube reduction process, reduces the lateral compression of the superconducting strip by the copper sheath 1 during the reduction process, and maximizes the preservation of the strip's own performance.

[0042] Step 5, Conductor Soldering: Soldering can ensure that there is no relative slippage between the strips, thus increasing mechanical strength, and can also enhance the ability of current redistribution between the strips. Specifically, the solder is melted under certain pressure and fully filled in the gaps between the superconducting strip 3 and the copper cap 2, the copper base 4, the copper cap 2 and the copper base 4, and the block structure and the copper sheath 1, thereby preparing a strong superconducting conductor. The soldering temperature is controlled below 200℃.

[0043] Although the illustrative specific embodiments of the present invention have been described above to enable those skilled in the art to understand the invention, it should be understood that the invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes will be obvious as long as they are within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of the present invention are protected.

Claims

1. A fabrication process for a high-strength composite-clad stacked high-temperature superconducting conductor structure, characterized in that: The high-temperature superconducting conductor structure includes a superconducting tape, a copper cap, a copper base, and a copper sheath. The copper cap and copper base are stepped. The superconducting tape is composed of multiple REBCO high-temperature superconducting tapes stacked together to form a stacked structure with a rectangular or square cross-section. The copper cap and copper base are used to encapsulate the superconducting tape. After being twisted together, the tape is inserted into the copper sheath and finally fabricated into a superconducting conductor by soldering. The preparation process includes the following steps: Step 1: Arrange multiple REBCO high-temperature superconducting tapes neatly to form a stacked structure with a rectangular or square cross-section; Step 2: Place the stacked strip into the groove between the copper cap and the copper base to form a block structure with a circular cross-section; Step 3: Fix the ends of the block structure and twist it along the center line at a predetermined pitch to obtain the twisted conductor; Step 4: Insert the twisted conductor into the copper sheath and reduce the diameter of the copper sheath; Step 5: Finally, solder is filled between the superconducting tape and the copper cap, the copper base, the copper cap and the copper base, and the block structure and the copper sheath by soldering, thereby preparing the high-strength composite sheath stacked high-temperature superconducting conductor structure. Step 4 includes: during the diameter reduction process, the stepped copper cap and copper bottom structure can be positioned to reduce the lateral compression of the superconducting strip by the copper cladding during the diameter reduction process, and to maintain the performance of the strip itself to the maximum extent. Step 5 includes: the soldering method involves using pressure to melt the solder and fully fill the gaps between the superconducting tape and the copper cap, the copper base, the copper cap and the copper base, and the block structure and the copper sheath, with the soldering temperature controlled below 200 ℃.

2. The manufacturing process of claim 1, wherein: Step 1 includes: The REBCO high-temperature superconducting tape is 0.1 mm thick and 3 mm wide, stacked into a 3×3 mm cross-sectional structure, and wrapped with copper-clad tape at equal intervals to prevent relative slippage between the tapes.

3. The preparation process according to claim 1, characterized in that: Step 3 includes: The two ends of the fixed block structure are twisted simultaneously, and the twisting pitch needs to be greater than the critical pitch that the high-temperature superconducting tape can withstand.

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