A jointless high-temperature superconducting magnet and a preparation method thereof

Abstract

This invention discloses a seamless high-temperature superconducting magnet, relating to the field of high-temperature superconducting magnet fabrication. The seamless high-temperature superconducting magnet includes: a magnet frame and at least one set of superconducting coils; the superconducting coil sets include a first double-coil and a second double-coil; the two double-coil sets are placed laterally; the superconducting coil sets are wound using a seamless winding method. The seamless winding method involves placing a circular frame tangentially between the upper and lower separated sections of the target strip; passing the left end of the target strip through the central aperture and returning it to its original position; winding the upper separated section onto the corresponding tangential circular frame to form the first double-coil; and winding the lower separated section onto the corresponding tangential circular frame to form the second double-coil. During operation, an excitation current is applied to each of the first and second double-coil sets in parallel. This invention avoids superconducting magnet joints and enables steady-state operation.

Description

Technical Field

[0001] The invention relates to the field of high-temperature superconducting magnet preparation, and in particular to a jointless high-temperature superconducting magnet and a preparation method thereof. Background Art

[0002] REBCO, composed of rare earth (RE), barium (Ba), copper (Cu), and oxygen (O), is a second-generation high-temperature superconducting material with a high critical transition temperature and strong current-carrying capacity. It is widely used in the field of magnetic field technology. The superconducting magnet technology wound with the second-generation high-temperature superconducting tape has an irreplaceable position in the fields of controlled nuclear fusion magnetic confinement, particle accelerators, and magnetic resonance imaging. Compared with traditional electromagnets, closed-loop superconducting magnets have lower losses due to the zero resistance effect, can achieve higher magnetic field strength, and operate more stably. At present, the joint technology is a major factor restricting the development of REBCO in the application of superconducting magnets. As a copper oxide, the joint connection of REBCO is not as easy as that of low-temperature superconductors. Special processes such as hot pressing and annealing in vacuum are often used in the production process. The joint performance will also decline compared with the original tape, and it is difficult to stably and repeatedly prepare superconducting joints with good performance. Summary of the invention

[0003] Based on this, an embodiment of the present invention provides a jointless high-temperature superconducting magnet and a method for preparing the same, which avoids superconducting magnet joints and can achieve steady-state operation.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] A jointless high-temperature superconducting magnet comprises: a magnet frame and at least one superconducting coil group; the superconducting coil group comprises a first double-pancake coil and a second double-pancake coil; the first double-pancake coil and the second double-pancake coil are placed sideways; the first double-pancake coil and the second double-pancake coil are respectively sleeved on one of the magnet frames; one of the magnet frames comprises at least two annular frames;

[0006] The superconducting coil assembly is wound by a jointless winding method; the jointless winding method is:

[0007] Determine a target strip; the target strip includes a left end, a right end, a middle upper separation strip and a middle lower separation strip; the target strip is obtained by separating the portion of the superconducting strip except the left end and the right end along the center line; the gap between the middle upper separation strip and the middle lower separation strip is a separation gap;

[0008] Place one of the circular ring frames in the magnet frame tangent to the middle upper separation strip, place another circular ring frame in the magnet frame tangent to the middle lower separation strip, pass the left end of the target strip through the middle pore and return to the original position, so that the middle upper separation strip is wound on the corresponding tangent circular ring frame to form a first double-pancake coil, and the middle lower separation strip is wound on the corresponding tangent circular ring frame to form a second double-pancake coil; the middle pore is the separation gap between the magnet frame and the right end;

[0009] During operation, an excitation current is supplied to each of the first double-pancake coil and the second double-pancake coil in parallel.

[0010] Optionally, when there are multiple groups of superconducting coils, a plurality of the first double-pancake coils are stacked; and a plurality of the second double-pancake coils are stacked.

[0011] Optionally, the magnet skeleton further comprises: two circular tube skeletons;

[0012] When there are multiple groups of superconducting coils, multiple first double-pancake coils sleeved with the circular frame are stacked and sleeved on one circular tube frame; multiple second double-pancake coils sleeved with the circular frame are stacked and sleeved on another circular tube frame.

[0013] Optionally, the jointless high-temperature superconducting magnet further includes: a Dewar packaging barrel;

[0014] The Dewar packaging barrel is used to package the superconducting coil assembly and the magnet frame in a liquid nitrogen environment.

[0015] Optionally, the jointless high temperature superconducting magnet further includes: a first current lead and a second current lead;

[0016] The first current lead is connected to each coil in the first double-pancake coil respectively; the first current lead is used to excite each coil in the first double-pancake coil in parallel;

[0017] The second current lead is connected to each coil in the second double-pancake coil respectively; the second current lead is used to excite each coil in the second double-pancake coil in parallel.

[0018] Optionally, an insulating layer is provided between the circular ring skeleton and the middle upper separation strip and the middle lower separation strip.

[0019] Optionally, the Dewar packaging barrel is made of stainless steel.

[0020] The present invention also provides a method for preparing a jointless high-temperature superconducting magnet, the method for preparing the jointless high-temperature superconducting magnet described above, the method comprising:

[0021] Separating the superconducting tape except the left end and the right end along the center line to obtain a target tape; the target tape includes the left end, the right end, the middle upper separation tape and the middle lower separation tape; the gap between the middle upper separation tape and the middle lower separation tape is the separation gap;

[0022] Place one of the circular rings in the magnet skeleton tangentially to the middle upper separation strip, place another circular ring in the magnet skeleton tangentially to the middle lower separation strip, pass the left end of the target strip through the middle pore and return to the original position, so that the middle upper separation strip is wound on the corresponding tangent circular ring skeleton to form a first double-pancake coil, and the middle lower separation strip is wound on the corresponding tangent circular ring skeleton to form a second double-pancake coil; the middle pore is the separation gap between the magnet skeleton and the right end;

[0023] The first double-pancake coil and the second double-pancake coil are placed sideways.

[0024] Optionally, placing one of the circular ring frames in the magnet frame tangent to the middle upper separation strip, placing another circular ring frame in the magnet frame tangent to the middle lower separation strip, passing the left end of the target strip through the middle pore and returning to the original position, so that the middle upper separation strip is wound on the corresponding tangent circular ring frame to form a first double-pancake coil, and the middle lower separation strip is wound on the corresponding tangent circular ring frame to form a second double-pancake coil, specifically including:

[0025] Place one of the circular ring frames in the magnet frame tangent to the middle upper separation strip, place another circular ring frame in the magnet frame tangent to the middle lower separation strip, and wind the target strip around the transition frame from the left end for a set distance, wherein the set distance is less than the distance between the left end and the circular ring frame;

[0026] The wound transition skeleton is passed through the middle gap and returned to its original position, and the strip wound on the transition skeleton is released, so that the middle upper separation strip is wound on the corresponding tangent circular ring skeleton to form a first double-pancake coil, and the middle lower separation strip is wound on another corresponding tangent circular ring skeleton to form a second double-pancake coil.

[0027] Optionally, the method for preparing the jointless high temperature superconducting magnet further includes:

[0028] Connecting each coil of the first double-pancake coil to a first current lead respectively;

[0029] Each coil of the second double-pancake coil is connected to a second current lead respectively.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The embodiment of the present invention provides a jointless high-temperature superconducting magnet. The superconducting coil group in the jointless high-temperature superconducting magnet is wound by a jointless winding method. The parts of the superconducting tape except the left end and the right end are separated along the center line, and a connection part is reserved, thereby avoiding superconducting joints and realizing resistance-free connection, and steady-state operation can be achieved; the middle upper separated tape and the middle lower separated tape are respectively wound into double-pancake coils, and the magnet units formed by the double-pancake coils being sleeved on corresponding circular ring skeletons are flat up and down, and there is no tape transition between the units, which is conducive to unit stacking; the first double-pancake coil and the first double-pancake coil are placed sideways. The realization of this "side separation" concept can generate two central magnetic fields at the same time, cleverly avoiding the shortcomings of difficult and unstable production of superconducting joints, and the assembly is more concise, which is of great significance for the preparation of a superconducting magnet with steady-state operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0033] Figure 1 A structural diagram of a jointless high-temperature superconducting magnet provided by an embodiment of the present invention;

[0034] Figure 2 A side view of a jointless high temperature superconducting magnet provided by an embodiment of the present invention;

[0035] Figure 3 A schematic diagram of the structure of a superconducting coil assembly provided in an embodiment of the present invention;

[0036] Figure 4 A schematic diagram of the structure of two superconducting coil groups superimposed on each other provided in an embodiment of the present invention;

[0037] Figure 5 A schematic diagram of the structure of four superconducting coil groups superimposed in an embodiment of the present invention.

[0038] Explanation of symbols: 1-Dewar packaging barrel, 2-room temperature magnetic field hole, 3-right end, 4-left end, 5-first double-pancake coil, 6-second double-pancake coil, 7-magnet skeleton, 8-second current lead, 9-first current lead, 10-middle upper separation strip, 11-middle lower separation strip. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] The embodiment of the present invention utilizes jointless technology, proposes a superconducting magnet structure with "lateral separation", and utilizes second-generation superconducting tapes to achieve steady-state operation of a jointless closed-loop magnet at or below the liquid nitrogen temperature range. Therefore, this embodiment is of great significance in the steady-state operation of superconducting magnets without resistance, and also has broad application prospects in fields requiring steady-state magnetic fields, such as magnetic resonance imaging technology.

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] See also Figure 1 and Figure 2 The jointless high-temperature superconducting magnet of this embodiment includes: a magnet skeleton 7 and at least one group of superconducting coil groups; the superconducting coil group includes a first double-pancake coil 5 and a second double-pancake coil 6; the first double-pancake coil 5 and the second double-pancake coil 6 are placed sideways; the first double-pancake coil 5 and the second double-pancake coil 6 are respectively sleeved on one of the magnet skeletons 7; one of the magnet skeletons 7 includes at least two circular skeletons.

[0043] See also Figure 3 The superconducting coil group is wound by a jointless winding method, and the superconducting coil group is composed of a plurality of jointless closed coils. The jointless winding method is:

[0044] Determine a target strip; the target strip includes a left end portion 4, a right end portion 3, a middle upper separation strip 10 and a middle lower separation strip 11; the target strip is obtained by separating the portion of the superconducting strip except the left end portion and the right end portion along the center line; the gap between the middle upper separation strip 10 and the middle lower separation strip 11 is a separation gap.

[0045] One of the circular ring frames in the magnet skeleton 7 is placed tangentially to the middle upper separation strip 10, and another circular ring frame in the magnet skeleton 7 is placed tangentially to the middle lower separation strip 11. The left end 4 of the target strip passes through the middle pore and returns to the original position, so that the middle upper separation strip 10 is wound on the corresponding tangent circular ring frame to form a first double-pancake coil 5, and the middle lower separation strip 11 is wound on the corresponding tangent other circular ring frame to form a second double-pancake coil 6; the middle pore is the separation gap between the magnet skeleton 7 and the right end 3. The first double-pancake coil 5 and the second double-pancake coil 6 contain room temperature magnetic field holes 2. The first double-pancake coil 5 and the second double-pancake coil 6 are both called superconducting coils, also called jointless coils. A double-pancake coil and a magnet skeleton 7 form a magnet unit.

[0046] The jointless high-temperature superconducting magnet of this embodiment, when working, passes an excitation current in parallel to each coil of the first double-pancake coil 5 and the second double-pancake coil 6. The room temperature magnetic field hole is a through-hole structure, which is generated by the superconducting coils on both sides and is the main area for generating the magnetic field. The magnetic fields generated by the apertures on both sides of the jointless magnet are in opposite directions, which play a role in mutually enhancing the magnetic field. The jointless coil uses the intact endpoints (left end 4 and right end 3) retained by the target strip to complete the closure; the magnetic field is superimposed by using "lateral separation", which enhances the magnetic field while avoiding the magnetic field cancellation caused by the upper and lower separation.

[0047] In one example, when there are multiple groups of superconducting coils, multiple first double-pancake coils 5 are stacked; multiple second double-pancake coils 6 are stacked. The structure after two groups of superconducting coils are stacked is as follows: Figure 4 As shown, the structure after the four groups of superconducting coils are superimposed is as follows Figure 5 shown. Figure 3-Figure 5 In the figure, the direction of the hollow arrow is the direction of the current in the closed coil, and the solid arrow is the direction of the magnetic field generated by the closed coil. Each closed coil can achieve closed operation without resistance. When the superconducting magnet is excited, multiple coils are connected in parallel, and the magnetic field strength is enhanced by superposition of coils. The superconducting magnet designed in this embodiment can be extended in theoretical length, and has great potential in the preparation of large colliders and high-energy accelerators.

[0048] The jointless high-temperature superconducting magnet overcomes the application of REBCO joints in the field of superconducting magnets, uses a centerline separation solution to avoid superconducting joints. The "side separation" solution makes it more convenient and simple to stack multiple double-pancake coils, which is of great significance for preparing a magnet with jointless steady-state closed-loop operation.

[0049] In one example, the magnet skeleton 7 further includes: two circular tube skeletons.

[0050] When there are multiple groups of superconducting coils, multiple first double-pancake coils 5 sleeved with the circular frame are stacked on one circular tube frame; multiple second double-pancake coils 6 sleeved with the circular frame are stacked on another circular tube frame.

[0051] Specifically, the ring frame is used to wind the double pancake coil, and an insulation design is adopted between the ring frame and the superconducting tape, such as an insulation layer is provided between the ring frame and the middle upper separation tape 10 and the middle lower separation tape 11. The circular tube frame supports and strings the ring frame and extends the length of the magnet.

[0052] In one example, the jointless high-temperature superconducting magnet further includes a current lead, which is a component used to apply excitation current to the superconducting magnet to complete the excitation of the magnet coil. Multiple superconducting coils can be connected at the same time to excite each coil closing unit in parallel.

[0053] Specifically, the current lead includes: a first current lead 9 and a second current lead 8. The first current lead 9 is respectively connected to each coil in the first double-pancake coil 5; the first current lead 9 is used to excite each coil in the first double-pancake coil 5 in parallel. The second current lead 8 is respectively connected to each coil in the second double-pancake coil 6; the second current lead 8 is used to excite each coil in the second double-pancake coil 6 in parallel.

[0054] In one example, the jointless high-temperature superconducting magnet further includes: a Dewar packaging barrel 1.

[0055] The Dewar packaging barrel 1 is used to package the superconducting coil group, the magnet skeleton 7, the first current lead 9 and the second current lead 8 in a liquid nitrogen environment. Specifically, the material of the Dewar packaging barrel 1 can be stainless steel, and the magnet skeleton 7, the superconducting coil group, the first current lead 9 and the second current lead 8 are all arranged in the Dewar packaging barrel 1. The vacuum insulation and heat shielding technology are used to package the entire magnet in liquid nitrogen to prevent the influence of environmental heat convection and heat radiation on the temperature in the packaging barrel.

[0056] The working principle of the present invention is:

[0057] By separating the center line of the wide strip and reserving the connection part, superconducting joints are avoided and resistance-free connection is achieved. The two sides of the separated strip are wound into double pancake coils respectively, and the magnet units formed are flat up and down, and there is no strip transition between the units. The coil adopts the "lateral separation" scheme to avoid magnetic field cancellation and strip flipping. The coil assembly of the magnet is completed by superimposing multiple closed superconducting coils. The present invention is of great significance for the preparation of stronger steady-state operating magnets.

[0058] In practical applications, the winding steps of the jointless high temperature superconducting magnet in the above embodiment are as follows:

[0059] (1) Mark the center line of the superconducting tape, reserve the end points on both sides, and separate the remaining parts along the center line to obtain the target tape.

[0060] (2) First, half of the target tape is wound as a whole on a transition frame with the same width as the tape, and the other half of the tape is wound on two circular frames in one direction. After winding one side of the superconducting coil, the remaining tape is released from the transition frame, thereby completing the winding of the two layers inside the coil to obtain the first superconducting coil and the second superconducting coil.

[0061] (3) After the winding of the two side coils (i.e., the first superconducting coil and the second superconducting coil) is completed, they are respectively installed on the left and right circular tube frames of the superconducting magnet using the "lateral separation" scheme, and the parts close to the end points are respectively connected to the current leads and the superconducting switches.

[0062] (4) The winding of the superconducting magnet is completed by stacking a plurality of first superconducting coils and stacking a plurality of second superconducting coils.

[0063] The jointless high-temperature superconducting magnet of this embodiment cleverly avoids the disadvantage of the difficulty in making the joints of RECBO strips, adopts an innovative solution, and proposes a new high-temperature superconducting magnet structure. The main innovations are as follows: First, by separating the center lines of the wider strips and reserving the connection parts, superconducting joints are avoided and resistance-free connection is achieved. Second, the two sides of the separated strips are respectively wound into double-pancake coils, and the magnet units formed are flat up and down, and there is no strip transition between the units, which is conducive to unit stacking. Third, the coil adopts the "side separation" solution to avoid magnetic field cancellation and strip flipping, making the stacking of multiple coil units more convenient and simple, which is of great significance for the preparation of steady-state superconducting magnets.

[0064] The present invention also provides a method for preparing a jointless high-temperature superconducting magnet, the method for preparing the jointless high-temperature superconducting magnet in the above embodiment, the method comprising:

[0065] Step 101: Separate the portion of the superconducting tape except the left end and the right end along the center line to obtain a target tape; the target tape includes the left end 4, the right end 3, the middle upper separation tape 10 and the middle lower separation tape 11; the gap between the middle upper separation tape 10 and the middle lower separation tape 11 is a separation gap.

[0066] Step 102: Place one of the circular ring frames in the magnet skeleton 7 tangentially to the middle upper separation strip 10, and place another circular ring frame in the magnet skeleton 7 tangentially to the middle lower separation strip 11, pass the left end 4 of the target strip through the middle gap and return to its original position, so that the middle upper separation strip 10 is wound on the corresponding tangent circular ring frame to form a first double-pancake coil 5, and the middle lower separation strip 11 is wound on the other corresponding tangent circular ring frame to form a second double-pancake coil 6; the middle gap is the separation gap between the magnet skeleton 7 and the right end 3.

[0067] Step 103: Place the first double-pancake coil 5 and the second double-pancake coil 6 sideways.

[0068] In one example, step 102 specifically includes:

[0069] One of the circular skeletons in the magnet skeleton 7 is placed tangentially to the middle upper separation strip 10, and another circular skeleton in the magnet skeleton 7 is placed tangentially to the middle lower separation strip 11, and the target strip is wound on the transition skeleton starting from the left end 4 for a set distance, and the set distance is smaller than the distance between the left end 4 and the circular skeleton.

[0070] The wound transition skeleton is passed through the middle gap and returned to its original position, and the strip wound on the transition skeleton is released, so that the middle upper separation strip 10 is wound on the corresponding tangent circular ring skeleton to form a first double-pancake coil 5, and the middle lower separation strip 11 is wound on another corresponding tangent circular ring skeleton to form a second double-pancake coil 6.

[0071] In one example, the method for preparing the jointless high temperature superconducting magnet further includes:

[0072] Each coil in the first double-pancake coil 5 is connected to a first current lead 9 ; each coil in the second double-pancake coil 6 is connected to a second current lead 8 .

[0073] The method for preparing a jointless high-temperature superconducting magnet of the present embodiment adopts the idea of ​​"lateral separation" of the double-pancake coil to prepare a new high-temperature superconducting magnet structure, avoiding superconducting magnet joints. It is a resistance-free closed-loop structure and is of great significance in the field of winding jointless second-generation high-temperature superconducting magnets.

[0074] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0075] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A jointless high temperature superconducting magnet, characterized in that: include: A magnet frame and at least one superconducting coil group; the superconducting coil group includes a first double-pancake coil and a second double-pancake coil; The first double-pancake coil and the second double-pancake coil are placed sideways; the first double-pancake coil and the second double-pancake coil are respectively sleeved on one of the magnet frames; one of the magnet frames includes at least two circular ring frames; The superconducting coil assembly is wound by a jointless winding method; the jointless winding method is: Determine a target strip; the target strip includes a left end, a right end, a middle upper separation strip and a middle lower separation strip; the target strip is obtained by separating the portion of the superconducting strip except the left end and the right end along the center line; the gap between the middle upper separation strip and the middle lower separation strip is a separation gap; Place one of the circular ring frames in the magnet frame tangent to the middle upper separation strip, place another circular ring frame in the magnet frame tangent to the middle lower separation strip, pass the left end of the target strip through the middle pore and return to the original position, so that the middle upper separation strip is wound on the corresponding tangent circular ring frame to form a first double-pancake coil, and the middle lower separation strip is wound on the corresponding tangent circular ring frame to form a second double-pancake coil; the middle pore is the separation gap between the magnet frame and the right end; During operation, an excitation current is supplied to each of the first double-pancake coil and the second double-pancake coil in parallel.

2. A jointless high temperature superconducting magnet according to claim 1, characterized in that: When there are multiple groups of superconducting coils, a plurality of the first double-pancake coils are stacked; and a plurality of the second double-pancake coils are stacked.

3. A jointless high temperature superconducting magnet according to claim 2, characterized in that: The magnet skeleton also includes: two round tube skeletons; When there are multiple groups of superconducting coils, multiple first double-pancake coils sleeved with the circular frame are stacked and sleeved on one circular tube frame; multiple second double-pancake coils sleeved with the circular frame are stacked and sleeved on another circular tube frame.

4. The jointless high temperature superconducting magnet according to claim 1, characterized in that: Also includes: Dewar packaging barrel; The Dewar packaging barrel is used to package the superconducting coil assembly and the magnet frame in a liquid nitrogen environment.

5. The jointless high temperature superconducting magnet according to claim 1, characterized in that: Also includes: a first current lead and a second current lead; The first current lead is connected to each coil in the first double-pancake coil respectively; the first current lead is used to excite each coil in the first double-pancake coil in parallel; The second current lead is connected to each coil in the second double-pancake coil respectively; the second current lead is used to excite each coil in the second double-pancake coil in parallel.

6. The jointless high temperature superconducting magnet according to claim 1, characterized in that: An insulating layer is arranged between the circular ring frame and the middle upper separation strip and the middle lower separation strip.

7. The jointless high temperature superconducting magnet according to claim 4, characterized in that: The material of the Dewar packaging barrel is stainless steel.

8. A method for preparing a jointless high-temperature superconducting magnet, characterized in that: The preparation method is used to prepare the jointless high-temperature superconducting magnet according to any one of claims 1 to 7, and the preparation method comprises: Separating the superconducting tape except the left end and the right end along the center line to obtain a target tape; the target tape includes the left end, the right end, the middle upper separation tape and the middle lower separation tape; the gap between the middle upper separation tape and the middle lower separation tape is the separation gap; Place one of the circular rings in the magnet skeleton tangentially to the middle upper separation strip, place another circular ring in the magnet skeleton tangentially to the middle lower separation strip, pass the left end of the target strip through the middle pore and return to the original position, so that the middle upper separation strip is wound on the corresponding tangent circular ring skeleton to form a first double-pancake coil, and the middle lower separation strip is wound on the corresponding tangent circular ring skeleton to form a second double-pancake coil; the middle pore is the separation gap between the magnet skeleton and the right end; The first double-pancake coil and the second double-pancake coil are placed sideways.

9. The method for preparing a jointless high temperature superconducting magnet according to claim 8, characterized in that: The method comprises placing one of the circular ring frames in the magnet frame tangent to the middle upper separation strip, placing another circular ring frame in the magnet frame tangent to the middle lower separation strip, passing the left end of the target strip through the middle aperture and returning to the original position, so that the middle upper separation strip is wound on the corresponding tangent circular ring frame to form a first double-pancake coil, and the middle lower separation strip is wound on the corresponding tangent circular ring frame to form a second double-pancake coil, which specifically includes: Place one of the circular ring frames in the magnet frame tangent to the middle upper separation strip, place another circular ring frame in the magnet frame tangent to the middle lower separation strip, and wind the target strip around the transition frame from the left end for a set distance, wherein the set distance is less than the distance between the left end and the circular ring frame; The wound transition skeleton is passed through the middle gap and returned to its original position, and the strip wound on the transition skeleton is released, so that the middle upper separation strip is wound on the corresponding tangent circular ring skeleton to form a first double-pancake coil, and the middle lower separation strip is wound on another corresponding tangent circular ring skeleton to form a second double-pancake coil.

10. The method for preparing a jointless high temperature superconducting magnet according to claim 8, characterized in that: Also includes: Connecting each coil of the first double-pancake coil to a first current lead respectively; Each coil of the second double-pancake coil is connected to a second current lead respectively.

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