Packaging tape preparation method, packaging tape and uninsulated coil

Abstract

The invention provides a packaging tape preparation method, a packaging tape and an uninsulated coil, and the method comprises the following steps: a strengthening drawing step: providing a coating layer, and carrying out strengthening drawing processing treatment on the coating layer to obtain a drawing coating layer; and a packaging step: placing the drawing coating layers on the upper side and the lower side of the superconducting tape, covering the superconducting tape through welding equipment, and carrying out extrusion shaping to realize packaging of the superconducting tape so as to obtain a packaging tape. The packaging tape packaged by the reinforced drawing coating layer has a more precise size, the yield is greatly improved, and a high-quality non-insulation coil can be manufactured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high-temperature superconducting tapes, in particular, to a packaging tape preparation method based on reinforced drawing processing of a cladding layer, a packaging tape and an uninsulated coil. BACKGROUND

[0002] High-temperature superconducting tapes have a wide range of applications in energy, power, transportation, medical care, and large scientific devices. However, due to the limitations of the material itself or the manufacturing process, there are still many weaknesses in superconducting tapes. The second-generation high-temperature superconducting tapes protected by silver alone usually cannot meet the application requirements. The common practice internationally is to perform surface copper plating treatment on them, that is, to electroplate a copper layer of 1-80 μm on the surface of the superconducting tapes that have been plated with silver. Such superconducting tapes strengthened by electroplating can already adapt to some application environments, but they still cannot meet the requirements of many superconducting application conditions. Therefore, some applications with more severe conditions require the superconducting tapes plated with copper to be packaged and strengthened, and the reasons are as follows: 1. The superconducting tapes need to have thicker and more secure protective layers for superconducting application products; 2. The superconducting tapes need to have surface oxidation resistance for superconducting application products; 3. The superconducting tapes need to have good geometric uniformity for superconducting application products; 4. The superconducting tapes need to have few defects for superconducting application products; and 5. The superconducting tapes need to have protective layers of other materials for some superconducting application products.

[0003] Generally, the superconducting tapes plated with copper need to be packaged and strengthened for products at the end of superconducting applications. The common packaging materials are red copper, brass or stainless steel tapes as upper and lower cladding layers to wrap the intermediate superconducting tapes. The cladding layers and superconducting tapes are placed in the corresponding positions and sent into and out of a high-temperature soldering furnace through a guide roller group. Excess solder is removed by a scraper and extruded into a packaging superconducting tape with a "sandwich" structure. However, there are still many problems and challenges in applying superconducting materials to specific devices. For example, these materials need to go through joint making, coil winding, epoxy impregnation, vacuum pouring, rapid cooling and heating, a large number of cold and hot cycles, stress caused by large magnetic fields, impact of large currents, and other complex working conditions.

[0004] The use of uninsulated coils is required for the production of high-temperature superconducting magnet, pulsed high-field coil and other application devices, and these magnets are usually composed of multiple single-pie uninsulated coil pies stacked together (such as Figure 1 ). Since there is no insulating layer as a buffer between the packaging superconducting tapes used to wind the single-pie uninsulated high-field coil, and higher and more uniform tension is required for winding, the cumulative error of the geometric dimensions of the packaging superconducting tapes will cause the coil to be wound incorrectly ( Figure 2 ), and even partially "skip turns" ( Figure 3), that is, in the early stage of single pancake coil manufacturing winding process, which will greatly reduce the winding efficiency, and even lead to the whole coil superconducting tape scrap.

[0005] Further encapsulation band geometry defects will lead to uneven winding of the whole coil or present as Figure 4 "UFO-shaped", and the magnet preparation requires high flatness of the coil stack, using such single pancake coil to make multi-layer pancake coil stack applied to high field magnet, will cause the stability of cold conduction to decline, the electromagnetic performance to deteriorate, and finally greatly reduce its performance and operation reliability, leading to the magnet cannot be used.

[0006] Therefore, higher and more accurate requirements are needed for the geometry of high temperature superconducting tape after encapsulation. In order to further explore these abnormal problems, we disassemble the damaged coil encapsulation tape, and observe and analyze the cross section of the tape, and find that there are two major problems with this encapsulation tape: edge soldering tin leakage and geometry problem. And these cross section pictures show that the size of the middle superconducting tape is normal, and the main problem is concentrated on the 4-12mm wide and 50-300um thick cladding layer outside, which is the biggest problem leading to encapsulation tape defects, as shown in Figure 5 .

[0007] The specific reason is that the processing technology of this cladding layer is a relatively extensive traditional processing method, which is different from the super-precision processing of superconducting tape. The traditional cladding layer processing is to press the copper raw material plate into a thin plate and then further press it into a foil, and finally cut it by rolling shear. Rolling shear cannot achieve 100% no-bur edge processing, which leads to the following problems of this cladding layer:

[0008] 1. During the rolling shear process, due to the gap matching of the tool and the tool edge blunting or chipping problem, burr is easy to produce after rolling shear, which makes the encapsulation cladding layer naturally form local geometric defects, as shown in Figure 6 . In addition, this defect often appears intermittently or in segments, which is difficult to completely avoid by adjusting equipment and process, so the yield of the cladding layer after cutting processing is difficult to control, as shown in Figure 7 . 2. In addition to the common burr problem of the cutting processing cladding layer, there is also a certain straightness problem of the tape caused by the S-shaped tool path of the rolling shear knife during cutting, which makes the cladding layer still exist distortion after straightening and encapsulation, causing the encapsulation tape to be thick on both sides and thin in the middle, and there is a serious tin leakage phenomenon, as shown in Figure 8 . In contrast, the encapsulation cross section thickness consistency of the cladding layer made by using normal cladding layer is good, and the solder column can tightly wrap the end of the tape, as shown in Figure 9 .

[0009] Besides rolling into wide strips and then slitting, drawing is also a process for preparing thin strips. For example... Figure 10 As shown, the drawing process first treats the roundness of the cladding material in a hot liquid furnace and its dies. Then, the rounded cladding undergoes a series of processes including roll forming and drawing. This one-step drawing process, eliminating the need for slitting, avoids the burr problem associated with mechanical slitting, resulting in more stable quality and performance of the strip along its length. However, conventional drawing processes still suffer from defects such as uneven internal structure and difficulty in precise dimensional control, leading to fatal problems in the prepared cladding. 1. The drawn overlay has a large edge transition radius, which means that the ends of the packaging strip cannot provide sufficient clamping force through capillary action during subsequent packaging processes, thus failing to form effective solder pillars. Figure 11 As shown, the anti-delamination performance is poor; however, the smaller edge transition radius provides a good capillary environment for solder at the end of the cladding layer, thereby forming a strong solder pillar that wraps the superconducting strip, such as... Figure 12 .

[0010] II. The internal structure of the coating material produced solely by drawing is extremely uneven, and it needs to be reinforced by scraper extrusion during subsequent encapsulation processes. Figure 13 This can easily lead to a problem of excessive thickness difference on both sides of the cross-section. Figures 14-16 Furthermore, after extreme cold or heat, there is a significant degradation in mechanical properties.

[0011] In summary, the defects in the encapsulation layer and the encapsulation technology urgently need further solutions. Summary of the Invention

[0012] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing a packaging tape, the packaging tape itself, and an uninsulated coil.

[0013] A method for preparing a packaging tape according to the present invention includes: Enhanced drawing step: Provide a coating layer, and perform enhanced drawing processing on the coating layer to obtain a drawn coating layer; Encapsulation steps: The drawn coating layer is placed on the upper and lower sides of the superconducting strip, and then bonded together using welding equipment. After extrusion and shaping, the superconducting strip is encapsulated to obtain an encapsulated strip.

[0014] Furthermore, the strengthening drawing step includes: rolling and shaping, drawing process and mechanical strengthening treatment.

[0015] Furthermore, the strengthening drawing step includes: rolling and shaping, pre-drawing, pre-strengthening, secondary multi-pass drawing, and secondary strengthening.

[0016] Furthermore, the pre-strengthening temperature is 350-550 degrees Celsius, and the secondary strengthening temperature is 120-200 degrees Celsius.

[0017] Furthermore, the transition radius of the rounded corner region at the edge of the drawn coating is ≤20μ; The thickness difference of the non-edge rounded corner regions in the cross-section of the drawn coating is <2μ.

[0018] Furthermore, the enhanced drawing step employs a drawing die for enhanced drawing, wherein the four corners of the cross-section of the drawing die are protruding rounded corners, and the four sides of the cross-section of the drawing die are smooth curves that curve inward. The smooth curve of the concave indentation is an Euler elastic line, which is continuously differentiable at its connection with the rounded corner and the straight edge. The concave curve is designed to minimize the energy functional under the constraint of smooth connection. :

[0019] Where L is the total length of the line, p represents the pressure load at the transition joint during drawing, and n represents the normal projection of the pressure load onto the mold boundary.

[0020] Furthermore, the packaging step includes: The drawn coating layer is placed on the upper and lower sides of the superconducting tape body, laminated by welding equipment, extruded and shaped by a scraper, and then cooled by non-contact cooling to obtain the encapsulated tape.

[0021] Furthermore, the mechanical properties of the encapsulation tape remain above 300 MPa during the encapsulation process.

[0022] The packaging tape provided by the present invention is prepared by the method described above.

[0023] According to the present invention, an uninsulated coil is obtained by winding the aforementioned encapsulation tape.

[0024] Compared with the prior art, the present invention has the following beneficial effects: On the one hand, the reinforced drawing process coating provided by this invention encapsulates superconducting tapes, resulting in encapsulated tapes with excellent geometric and mechanical properties. The coating qualification rate is increased to over 99%, eliminating the need for full inspection of raw materials; only partial sampling inspection is required, saving significant manpower for manual coating inspection and greatly improving the yield of encapsulated superconducting tapes. The reason for this is: 1) The coating layer is independently prepared through a reinforced drawing process, avoiding edge burrs and deformation caused by traditional slitting. The improved uniformity of the coating layer thickness also brings about overall geometric optimization of the packaging strip. The significant optimization of the edge transition arc radius solves the problem that the solder pillars on both sides of the packaging strip cannot be attached, thus forming a complete packaging coating structure with ideal geometry.

[0025] 2) The multiple heat treatments during the drawing process make the overall grain size of the coating layer uniform and increase its density, avoiding the thickness difference between the two ends of the packaging tape due to deformation caused by the scraper force during packaging; at the same time, it also significantly enhances the mechanical properties, preventing the yield strength of the packaging tape from rapidly decaying under short-term extreme cold and heat conditions.

[0026] On the other hand, the non-contact cooling method provided by this invention can be used to wind perfect uninsulated coils for users of magnet applications. This is because, due to the use of the non-contact cooling packaging method, the solder pillars on both sides of the packaging strip can fix the two coating layers more promptly, further reducing solder leakage defects. Attached Figure Description

[0027] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 It is a superconducting magnet composed of multiple single-panel uninsulated coils stacked together; Figure 2 A schematic diagram illustrating the misalignment of the coil winding caused by abnormal geometry of the encapsulated superconducting tape; Figure 3 This is due to a skipped turn occurring during the winding of an uninsulated coil; Figure 4 The coil is unevenly wound, resulting in a "flying saucer" shape; Figure 5 A cross-sectional view of the abnormally encapsulated superconducting strip in the damaged coil; Figure 6 This is a cross-sectional view of the coating layer that produces burr defects after roll shearing; Figure 7 This is an image showing the burr defects that appear in the segments after the roll shearing process. Figure 8 Cross-sectional view of the encapsulated superconducting strip prepared for the twisted cladding layer; Figure 9 A cross-sectional view of a standard packaged superconducting strip with no solder leakage at both ends and uniform thickness; Figure 10 This is a flow chart of a typical drawing process; Figure 11 Cross-sectional view of the encapsulated superconducting strip prepared for an edge transition arc radius that is too large; Figure 12Cross-sectional view of the encapsulated superconducting strip prepared for an edge transition arc radius conforming to the standard; Figure 13 This is a schematic diagram of a scraper compressing and reinforcing the strip material during the packaging process. Figure 14 This is a schematic diagram showing the thickness difference between the two ends of a normal coating layer after it has been reinforced by a scraper. Figure 15 This is a schematic diagram of the stress exerted on a typical drawn coating layer by the extrusion of a sealing scraper. Figure 16 This is a cross-sectional view of a coating layer with a thickness difference at both ends after being reinforced by a scraper extrusion. Figure 17 This is a schematic diagram illustrating the stress exerted on the reinforced pull-out coating layer by the encapsulation scraper according to the present invention. Figure 18 This is a cross-sectional view of the coating layer of the present invention, showing the thickness difference between the two ends of the reinforced drawing coating layer after being reinforced by a scraper; Figure 19 This is a flowchart illustrating the enhanced drawing process of the present invention. Figure 20 This invention features a high-precision mold with protruding rounded corners at all four corners. Figure 21 The stress-strain curves of the ordinary drawn coating layer of this invention and its tin-scraping process are shown below. Figure 22 The stress-strain curves of the coating layer in the enhanced drawing process and its after soldering are shown in this invention. Detailed Implementation

[0028] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0029] Example 1 like Figure 19 As shown, this embodiment provides a method for preparing a packaging tape based on a reinforced drawing process for the coating layer. The method includes a coating layer drawing process and a non-contact cooling and packaging process for the superconducting tape using the drawn coating layer. The execution steps include: S1: The coating layer is subjected to a strengthening drawing process to obtain a high-strength drawn coating layer.

[0030] S2: High-strength drawn cladding is used for encapsulation. The high-strength drawn cladding is placed on the upper and lower layers of the superconducting strip, with the superconducting strip in the middle. The cladding is wider than the superconducting strip, forming a stacked structure. The stacked structure is then placed in a tin furnace for lamination. It is then extruded and shaped by a scraper while being cooled in a non-contact manner, forming a packaged superconducting strip with a "sandwich" structure.

[0031] Specifically, step S1 includes: Rolling and shaping: The copper bars are passed through a low-temperature liquid furnace containing lubricant and rust remover. Inside the furnace, the roundness of the bars is calibrated to over 98% using nine calibration molds.

[0032] The process involves two rolling processes on copper bars, followed by pre-drawing through rectangular dies. After pre-strengthening at temperatures exceeding 350 degrees Celsius, the cladding layer, with its preliminary structure, undergoes a second, multi-stage drawing process using a secondary die with a four-cornered pyramidal convex shape. This finalized cladding layer is then further strengthened at 120-200 degrees Celsius. The drawing dies are hollow structures with specific shapes. Under tensile force, the strip, already possessing a certain shape and size, is forcibly pulled through several drawing dies with progressively smaller cross-sections, resulting in a product with a shape and size close to the exit shape of the drawing dies. The core of this process is "drawing," relying on high-precision, specific drawing molds to constrain the dimensions of the copper strip, causing the strip's dimensions to change under tensile stress.

[0033] The secondary mold is a rectangle with rounded corners, such as... Figure 20 As shown, the mold cross-section has convex arcs at the four corners and smooth, inwardly concave curves on all four sides. These inwardly concave curves are Euler elastic lines, and their continuity at the points where they connect with the rounded corners and straight edges leads to a rectangular cross-section of the drawn material. The radius of the rounded corners on all four sides is less than 8% of the coating thickness. The rounded corners are designed using interpolation functions, and all lines are based on energy functional theory. The upper continuous guide is produced by the cross-sectional transition arc radius of the covering strip pulled out by this specific mold ≤20μm, the tangential angle <3°, which is close to a standard right-angled rectangle.

[0034] The concave curve design minimizes the energy functional under smooth connectivity constraints. :

[0035] Where L is the total length of the line, p represents the pressure load at the transition connection during drawing, and n represents the normal unit vector of the mold outline curve. Here, the inner product of n and the pressure load represents the normal projection of the pressure load on the mold boundary.

[0036] After passing through this type of mold three times, the edge of the coating layer is approximately right-angled, increasing the amount of tin retained in the middle of the strip: In the strengthening process, the pre-strengthening temperature is higher than the secondary strengthening temperature, with a pre-strengthening temperature >350 degrees Celsius and a secondary strengthening temperature of 120-200 degrees Celsius. Multiple strengthening passes are combined to promote grain refinement, simultaneous recrystallization of the surface and core, and elimination of structural gradients. This helps improve the balance between the material's strength and its plasticity and toughness. Figure 17 As shown, this ensures that the coating layer maintains stable mechanical properties even after being subjected to high temperatures above 200 degrees Celsius in a tin furnace and non-contact cooling to below -100 degrees Celsius in a short period. The mechanical strengthening treatment ensures that the rectangular thickness difference in the non-rounded corner areas of the drawn coating layer is <2μm. Figure 18 As shown.

[0037] The drawn cladding layer is placed at the top and bottom layers, and the superconducting strip is placed in the middle layer. The top, middle, and bottom layers are then immersed in flux and laminated in a solder bath. A non-contact cooling device equipped with liquid nitrogen, which does not directly contact the strip, can instantly cool the molten solder, which is above its melting point, to its solidification temperature. After exiting the solder bath, the multilayer composite structure passes through the non-contact instant cooling device to form the encapsulated tape with the drawn cladding layer.

[0038] The cross-section of the prepared packaging strip is as follows Figure 9 The ends are flush, and the overall geometric uniformity is good. The thickness difference between the ends and the middle of the cross-section can be controlled within 10μm. In addition, the yield strength of the drawn coating before soldering is 335Rp. 0.2％ / MPa and 331Rp 0.2％ / MPa, yield strength after soldering is 320Rp 0.2％ / MPa and 324Rp 0.2％ / MPa, and the yield strength decreases by only 4.47% and 2.11% after soldering, such as Figure 22 As shown.

[0039] In this embodiment, secondary strengthening is employed to achieve uniform and refined grains in the coating layer. This prevents deformation after extrusion by the encapsulation scraper. Figure 17 , 18 As shown.

[0040] In this embodiment, the coating layer drawing process is employed, which improves the yield of the encapsulation coating layer to over 99%. This significantly reduces the manpower and time costs invested in the coating layer quality inspection process, thereby lowering the overall production cost of the encapsulation tape. As a result, mass production tasks can be handled more efficiently and with higher quality.

[0041] In this embodiment, a non-contact liquid nitrogen cooling device was used to optimize the packaging equipment, which can instantly cool the molten tin above its melting point to the molten tin solidification temperature, avoiding the problem of tin leakage and further improving the yield of the packaging tape.

[0042] In this embodiment, a non-contact cooling and encapsulation method for superconducting tapes using a drawn cladding layer significantly improves the yield of the encapsulated tape to over 99%. In application, the cladding layer drawing process avoids the problems of burrs and deformation caused by slitting. It significantly improves issues such as overall misalignment and uneven thickness of the encapsulated tape during subsequent encapsulation processes. The flush ends and overall sheathing of the encapsulated tape also result in a compact and geometrically regular overall cross-section of the coil after multi-layer stacking in superconducting applications, thus avoiding performance degradation or coil failure caused by friction between the tape ends. Avoiding the burr problem caused by slitting the cladding layer eliminates the risk of irregular sharp angles at the edges of the encapsulated tape piercing the insulating wrapping material and causing partial discharge in the coil. Furthermore, the improved uniformity of the overall thickness of the encapsulated tape allows for tighter and more regular winding of the magnet coil, greatly reducing problems such as "flying saucer" winding and coil skipping turns.

[0043] Comparative Example 1: (Removing secondary enhancement) Unlike the embodiments, this comparative example uses a method for encapsulating superconducting tapes with a drawn cladding layer. This method includes a cladding layer drawing process and a cladding layer encapsulation process for the superconducting tapes. The steps of the cladding layer drawing process include: The copper bars are passed through a low-temperature liquid furnace containing lubricant and rust remover, where the roundness of the bars is calibrated to over 98% using nine calibration molds.

[0044] The copper rod is rolled twice, then passed through a square die, and pre-strengthened at a temperature >350 degrees Celsius. A cladding layer with a preliminary structure is then applied. Figure 20 It has a four-corner pyramidal convex secondary mold.

[0045] The secondary drawing die is a rectangle with rounded corners, which allows the edge of the coating layer to be approximately right-angled after three drawing passes, thus increasing the tin retention in the strip. The drawn coating layer is placed at the upper and lower packaging strip positions, and the superconducting strip is placed at the middle layer position; the upper, middle and lower structure are immersed in flux and then laminated in a tin furnace; a non-contact cooling device is provided with liquid nitrogen, which does not come into direct contact with the strip, and can instantly cool the molten tin above the melting point temperature to the solidification temperature; after the multi-layer composite structure exits the tin furnace, it passes through a non-contact instant cooling device to form the drawn coating layer packaging strip.

[0046] like Figure 21 As shown, the yield strength of the ordinary drawn coating in Comparative Example 1 before tinning is 398Rp. 0.2％ / MPa and 397Rp 0.2％ / MPa, yield strength after soldering is 185Rp 0.2％ / MPa and 189Rp 0.2％The pressure is / MPa, which does not meet the standard of greater than 300MPa after tinning, and the yield strength decreases by as much as 53.52% and 52.39% after tinning.

[0047] Figure 22 The yield strength of the drawn coating layer before soldering in Example 1 is 335Rp. 0.2％ / MPa and 331Rp 0.2％ / MPa, yield strength after soldering is 320Rp 0.2％ / MPa and 324Rp 0.2％ / MPa, and the yield strength decreases by only 4.47% and 2.11% after tinning.

[0048] Comparative Example 2: (Mold without rounded corners) Based on Example 1, this comparative example uses a traditional rectangular drawing die instead of the die in Example 1. Specifically, the secondary drawing die used is a rectangular structure without protruding rounded corners, resulting in… Figure 11 The overcoating layer with an excessively large edge transition radius is prone to insufficient solder coverage.

[0049] Comparative Example 3: (using a slit coating layer) Unlike the embodiments, the encapsulation method for the slit-coated superconducting tape used in this comparative example includes the following steps: Step 1: Select a clean, defect-free roll of wide copper raw material and cut it into copper strips with a width of 4.75mm and a thickness of 150μm as the packaging coating layer. Step 2: Place the drawn coating layer on the upper and lower packaging tape positions, and place the superconducting tape in the middle layer position; after the upper, middle and lower structure is wetted with flux, it is put into the tin furnace for lamination; reduce non-contact instantaneous cooling.

[0050] The prepared coating layer is Figure 6 Due to the deformation and small burrs generated at the edges of the slitting coating, the edges of the encapsulation tape are uneven. The burrs at both ends of the coating are very severe, accounting for 3-40% of the total thickness.

[0051] In summary, this invention employs a non-contact cooling and encapsulation method for superconducting tapes using a drawn cladding layer. Through cladding layer drawing processes, including controlled feed dimensions, heat treatment during the drawing process, and bending and straightening after drawing, a drawn cladding layer with excellent thickness uniformity, straightness, and mechanical properties is produced. This improves the cladding layer yield to over 99%, significantly reducing manpower and time in the cladding layer quality inspection process, and substantially improving the quality and yield of the encapsulated tape. It also solves problems such as "flying saucer" shape and coil skipping issues encountered in superconducting applications. Furthermore, the use of a non-contact liquid nitrogen cooling device essentially eliminates the bulging problem caused by internal film delamination due to rapid cooling, further improving the overall yield of the encapsulated tape to over 90%.

[0052] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0053] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for preparing a packaging tape, characterized in that, include: Enhanced drawing step: Provide a coating layer, and perform enhanced drawing processing on the coating layer to obtain a drawn coating layer; Encapsulation steps: The drawn coating layer is placed on the upper and lower sides of the superconducting strip, and then bonded together using welding equipment. After extrusion and shaping, the superconducting strip is encapsulated to obtain an encapsulated strip.

2. The method for preparing the encapsulation tape according to claim 1, characterized in that, The strengthening drawing process includes: rolling and shaping, drawing process and mechanical strengthening treatment.

3. The method for preparing the encapsulation tape according to claim 1, characterized in that, The enhanced drawing process includes: rolling and shaping, pre-drawing, pre-strengthening, secondary multi-pass drawing, and secondary strengthening.

4. The method for preparing the encapsulation tape according to claim 3, characterized in that, The pre-strengthening temperature is 350-550 degrees Celsius, and the secondary strengthening temperature is 120-200 degrees Celsius.

5. The method for preparing the encapsulation tape according to claim 1, characterized in that, The radius of the transition arc in the edge rounded corner region of the cross-section of the drawn cladding layer is ≤20μ; The thickness difference of the non-edge rounded corner regions in the cross-section of the drawn coating is <2μ.

6. The method for preparing the encapsulation tape according to claim 1, characterized in that, The enhanced drawing step uses a drawing die for enhanced drawing. The four corners of the cross-section of the drawing die are protruding rounded corners, and the four sides of the cross-section of the drawing die are smooth curves that are concave inward. The smooth curve of the concave indentation is an Euler elastic line, which is continuously differentiable at its connection with the rounded corner and the straight edge. The concave curve is designed to minimize the energy functional under the constraint of smooth connection. : Where L is the total length of the line, p represents the pressure load at the transition joint during drawing, and n represents the normal projection of the pressure load onto the mold boundary.

7. The method for preparing the encapsulation tape according to claim 1, characterized in that, The packaging step includes: The drawn coating layer is placed on the upper and lower sides of the superconducting tape body, laminated by welding equipment, extruded and shaped by a scraper, and then cooled by non-contact cooling to obtain the encapsulated tape.

8. The method for preparing the encapsulation tape according to claim 1, characterized in that, The mechanical properties of the encapsulation tape remain above 300 MPa during the encapsulation process.

9. A packaging tape, characterized in that, It is prepared by the method described in any one of claims 1-8.

10. A non-insulated coil, characterized in that, It is obtained by winding the encapsulation tape as described in claim 9.

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