Low-loss high-temperature superconducting conductor and manufacturing method thereof

Abstract

The invention discloses a low-loss high-temperature superconducting conductor and a manufacturing method thereof, and relates to the technical field of superconducting conductors. The low-loss high-temperature superconducting conductor of the present invention comprises: a high-temperature superconducting tape; the magnetic thin strip is wound and bound outside the high-temperature superconducting strip, and the magnetic thin strip is made of amorphous iron alloy; a gap is formed between the outer metal sheath and the high-temperature superconducting strip wound and bound with the magnetic thin strip; the low-melting-point alloy solder is arranged in the gap; during preparation, a certain number of high-temperature superconducting strips are stacked and wound and bound by the magnetic thin strip, then the high-temperature superconducting strips are inserted into the outer metal sheath, and vacuum pressure impregnation is performed between the outer metal sheath and the stacked strips wound and bound by the magnetic thin strip by the low-melting-point alloy solder; according to the invention, the magnetic field acting on the stacked strip can be obviously weakened, the alternating current loss is reduced, and the magnetic shielding effect is obvious in a high field.

Description

Technical Field

[0001] The present invention relates to the technical field of superconducting conductors, and in particular to a low-loss high-temperature superconducting conductor and a manufacturing method thereof. Background Art

[0002] The second generation of high-temperature superconducting tapes has a high critical current density and high mechanical strength under high fields, and has important application prospects in the fields of nuclear fusion, high-energy ion accelerators, etc. In high-field large magnets, multiple high-temperature superconducting tapes need to be connected in parallel to form a high-temperature superconducting conductor to meet the high current carrying capacity. When superconducting conductors operate under alternating current or alternating external fields, AC losses will occur. AC losses greatly increase the cost of refrigeration, and excessive AC losses may cause superconducting magnets to quench and cause safety accidents. Therefore, it is necessary to take some measures to reduce the AC losses of high-temperature superconducting conductors.

[0003] At present, the commonly used methods to reduce the AC loss of high-temperature superconducting conductors are generally the following: one is to make the superconducting tape filaments multi-core; the other is to use twisting and transposition. However, multi-core filaments will increase the manufacturing cost of the tape, twisting and transposition will make the conductor preparation process more complicated, and twisting strain may cause the conductor performance to deteriorate.

[0004] In view of this, a low-loss high-temperature superconducting conductor and a method for manufacturing the same are proposed. Summary of the invention

[0005] The present invention aims to solve the technical problems that the existing methods for reducing the AC loss of high-temperature superconducting conductors are high in cost and easily cause the performance of the conductor to decline. The present invention aims to provide a low-loss high-temperature superconducting conductor and a method for making the same, which can significantly weaken the magnetic field acting on the stacked strips, thereby reducing the AC loss, and at the same time has an obvious magnetic shielding effect under high fields.

[0006] The present invention is achieved through the following technical solutions:

[0007] The first object of the present invention is to provide a low-loss high-temperature superconducting conductor, comprising:

[0008] High temperature superconducting tapes;

[0009] A magnetic thin ribbon is wound and bound outside the high-temperature superconducting ribbon, and the magnetic thin ribbon is an amorphous iron alloy;

[0010] An outer metal sheath has a gap between it and the high temperature superconducting tape wrapped with the magnetic tape;

[0011] The low melting point alloy solder is arranged in the gap.

[0012] As a further technical solution of the present invention, the high temperature superconducting tape is a stacked second generation high temperature superconducting tape.

[0013] As a further technical solution of the present invention, the cross-section of the high-temperature superconducting tape is square.

[0014] As a further technical solution of the present invention, the outer metal sheath material is copper, stainless steel, aluminum or aluminum alloy.

[0015] As a further technical solution of the present invention, the cross-section of the outer metal sheath is circular.

[0016] As a further technical solution of the present invention, the low melting point alloy solder is a low melting point Bi-Sn-In alloy.

[0017] As a further technical solution of the present invention, the melting point of the low melting point Bi-Sn-In alloy is 78°C.

[0018] A second object of the present invention is to provide a method for manufacturing a low-loss high-temperature superconducting conductor, comprising the following steps:

[0019] Stacking a plurality of high-temperature superconducting tapes and wrapping and bundling them with magnetic tapes;

[0020] Inserting the high temperature superconducting tape wrapped with the magnetic thin tape into the outer metal sheath;

[0021] The low melting point alloy solder is heated and melted, and then injected into the gap between the high temperature superconducting tape wrapped and bundled with magnetic thin tape and the outer metal sheath. The molten solder is solidified by a vacuum pressure impregnation process, and a low-loss high temperature superconducting conductor is obtained after solidification.

[0022] As a further technical solution of the present invention, the low melting point alloy solder is heated to a melting temperature of 90-100°C.

[0023] As a further technical solution of the present invention, in the vacuum pressure impregnation process, the vacuum degree of the gap in the outer metal sheath is 0.08-0.15Pa.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] 1. In the present invention, a magnetic thin strip is wrapped and tied around the outside of the stacked high-temperature superconducting tapes. The function of the magnetic thin strip is to conduct magnetism. When the high-temperature superconducting conductor operates under an alternating external field, the magnetic thin strip has the function of shielding the external magnetic field, so that the magnetic field directly acting on the stacked tapes is significantly weakened, thereby reducing AC loss.

[0026] 2. The magnetic ribbon of the present invention is an amorphous iron alloy soft magnetic material, which can effectively conduct magnetism compared with traditional aluminum ribbon or copper ribbon. Therefore, when an external variable magnetic field is applied to the conductor, the magnetic ribbon has the function of shielding the external magnetic field, so that the magnetic field directly acting on the stacked strips is significantly weakened, thereby reducing AC losses.

[0027] 3. The magnetic thin strip material of the present invention is an amorphous iron alloy, which has high saturation magnetic induction intensity, high magnetic permeability and low loss characteristics compared to silicon steel and Permalloy commonly used in current electrical applications, so that the magnetic shielding effect is still obvious under high fields.

[0028] 4. The solder impregnation between the outer metal sheath and the stacked high-temperature superconducting tapes wrapped and bound with magnetic thin strips of the present invention is low-melting-point alloy vacuum pressure impregnation. On the one hand, during the impregnation process, the molten low-melting-point alloy solder can penetrate into any gaps between the high-temperature superconducting tapes, so that the stacked high-temperature superconducting tapes form a whole; on the other hand, the stacked high-temperature superconducting tapes and the outer metal sheath have good mechanical, electrical and thermal connections, improving the thermal stability and mechanical properties of the conductor. In addition, the low-melting-point alloy solder of the present invention has a low melting point temperature, and the low melting point temperature can avoid damage to the high-temperature superconducting tape during the impregnation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0030] Figure 1 It is a schematic structural diagram of a low-loss high-temperature superconducting conductor of the present invention;

[0031] Figure 2 It is a schematic diagram of the end structure of the low-loss high-temperature superconducting conductor of the present invention.

[0032] Marks and corresponding parts names in the attached drawings:

[0033] 1- high temperature superconducting tape, 2- magnetic thin strip, 3- low melting point alloy solder, 4- outer metal sheath. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the technical solutions in the embodiments of the present invention are clearly and completely described below in combination with the embodiments and drawings. Obviously, the schematic implementation modes of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0035] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is apparent to one of ordinary skill in the art that these specific details are not necessarily employed to practice the present invention. In other embodiments, in order to avoid obscuring the present invention, well-known structures, circuits, materials, or methods are not specifically described.

[0036] Throughout the specification, references to "one embodiment," "an embodiment," "an implementation," or "an implementation" mean that a particular feature, structure, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment," "an embodiment," "an implementation," or "an implementation" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or implementation. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or implementations in any suitable combination and / or sub-combination. In addition, it will be appreciated by those of ordinary skill in the art that the figures provided herein are for illustrative purposes and that the figures are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] In the description of the present invention, the indicated orientation or position relationship is based on the orientation or position relationship shown in the drawings, or is the orientation or position relationship in which the product of the application is usually placed when in use, or is the orientation or position relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0038] Meanwhile, the terms "set", "assemble", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0040] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0041] If there is no special explanation, all the steps of the present application can be performed sequentially or randomly, preferably sequentially.

[0042] In order to solve the technical problems that the existing methods for reducing the AC loss of high-temperature superconducting conductors are high in cost and easily cause the performance of the conductor to deteriorate, the technical solution of the present invention is to provide a low-loss high-temperature superconducting conductor, comprising:

[0043] High temperature superconducting tape 1;

[0044] A magnetic thin strip 2 is wound and bound outside the high-temperature superconducting strip 1, and the magnetic thin strip 2 is an amorphous iron alloy;

[0045] There is a gap between the outer metal sheath 4 and the high temperature superconducting tape 1 wrapped with the magnetic thin tape 2;

[0046] The low melting point alloy solder 3 is arranged in the gap.

[0047] In the present invention, the magnetic thin strip 2 is wrapped and tied around the outside of the stacked high-temperature superconducting tapes 1. The function of the magnetic thin strip 2 is to conduct magnetism. When the high-temperature superconducting conductor operates under an alternating external field, the magnetic thin strip 2 has the function of shielding the external magnetic field, so that the magnetic field directly acting on the stacked tapes is significantly weakened, thereby reducing AC losses.

[0048] At the same time, the magnetic thin strip 2 of the present invention is an amorphous iron alloy soft magnetic material, which can effectively conduct magnetism compared to traditional aluminum thin strips or copper thin strips. Therefore, when an external variable magnetic field is applied to the conductor, the magnetic thin strip 2 has the function of shielding the external magnetic field, so that the magnetic field directly acting on the stacked strips is significantly weakened, thereby reducing the AC loss; and the amorphous iron alloy has high saturation magnetic induction intensity, high magnetic permeability and low loss characteristics compared to silicon steel and Permalloy commonly used in current electrical applications, so that the magnetic shielding effect under high fields is still obvious.

[0049] In one or more embodiments of the present invention, the high temperature superconducting tape 1 is a stacked second generation high temperature superconducting tape 1 .

[0050] In one or more embodiments of the present invention, the cross section of the high temperature superconducting tape 1 is square.

[0051] In one or more embodiments of the present invention, the outer metal sheath 4 is made of copper, stainless steel, aluminum or aluminum alloy.

[0052] In one or more embodiments of the present invention, the cross section of the outer metal sheath 4 is circular.

[0053] In one or more embodiments of the present invention, the low melting point alloy solder 3 is a low melting point Bi-Sn-In alloy.

[0054] In one or more embodiments of the present invention, the melting point of the low melting point Bi-Sn-In alloy is 78°C.

[0055] Based on the low-loss high-temperature superconducting conductor, a method for manufacturing a low-loss high-temperature superconducting conductor is provided, comprising the following steps:

[0056] A plurality of high-temperature superconducting tapes 1 are stacked and wrapped with magnetic tapes 2;

[0057] Inserting the high temperature superconducting tape 1 wrapped with the magnetic thin tape 2 into the outer metal sheath 4;

[0058] The low melting point alloy solder 3 is heated and melted, and injected into the gap between the high temperature superconducting tape 1 wrapped and bundled with the magnetic thin strip 2 and the outer metal sheath 4. The molten solder is solidified by a vacuum pressure impregnation process, and a low-loss high temperature superconducting conductor is obtained after solidification.

[0059] The solder impregnation between the stacked high-temperature superconducting tapes 1 wound and bound by the outer metal sheath 4 and the magnetic thin strip 2 of the present invention is low-melting-point alloy vacuum pressure impregnation. On the one hand, during the impregnation process, the molten low-melting-point alloy solder 3 can penetrate into any gap between the high-temperature superconducting tapes 1, so that the stacked high-temperature superconducting tapes 1 form a whole; on the other hand, the stacked high-temperature superconducting tapes 1 and the outer metal sheath 4 have good mechanical, electrical and thermal connections, and the thermal stability and mechanical properties of the conductor are improved. In addition, the low-melting-point alloy solder 3 of the present invention has a low melting point temperature, and the low melting point temperature can avoid damage to the high-temperature superconducting tape 1 during the impregnation process.

[0060] In one or more embodiments of the present invention, the low melting point alloy solder 3 is heated to a melting temperature of 90-100°C.

[0061] In one or more embodiments of the present invention, in the vacuum pressure impregnation process, the vacuum degree of the space inside the outer metal sheath 4 is 0.08-0.15Pa.

[0062] The technical solution of the present invention is further described in detail below in conjunction with embodiments.

[0063] It should be noted that the methods used in the examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained by those skilled in the art through commercial channels.

[0064] Example 1

[0065] A low-loss high-temperature superconducting conductor, such as Figure 1 and Figure 2 As shown, it includes a high temperature superconducting tape 1, a magnetic thin strip 2, an outer metal sheath 4 and a low melting point alloy solder 3.

[0066] The high temperature superconducting tape 1 is a stacked second-generation high temperature superconducting tape 1 , and the cross section of the stacked second-generation high temperature superconducting tape 1 is square.

[0067] The magnetic thin strip 2 is wound and tied outside the stacked high-temperature superconducting strip 1, and the magnetic thin strip 2 is an amorphous iron alloy soft magnetic material. The function of the magnetic thin strip 2 is to conduct magnetism. When the high-temperature superconducting conductor runs under an alternating external field, the magnetic thin strip 2 has the function of shielding the external magnetic field, so that the magnetic field directly acting on the stacked strips is significantly weakened, thereby reducing AC loss.

[0068] Compared with the conventional aluminum or copper thin strips, the magnetic thin strip 2 of the present invention can effectively conduct magnetism. Therefore, when the external variable magnetic field is applied to the conductor, the magnetic thin strip 2 has the function of shielding the external magnetic field, so that the magnetic field directly acting on the stacked strips is significantly weakened, thereby reducing AC loss. In addition, the material of the magnetic thin strip 2 of the present invention is an amorphous iron alloy, which has high saturation magnetic induction intensity, high magnetic permeability and low loss characteristics compared with silicon steel and permalloy commonly used in current electrical applications, so that the magnetic shielding effect under high field is still obvious.

[0069] There is a gap between the outer metal sheath 4 and the stacked high-temperature superconducting tape 1 wrapped with the magnetic thin strip 2; the outer metal sheath 4 is made of copper, stainless steel, aluminum or aluminum alloy, the cross-section of the outer metal sheath 4 is a hollow circle, and the inner wall of the outer metal sheath 4 is in contact with the low-melting-point alloy solder 3. Figure 2 As shown, the square-stacked second-generation high-temperature superconducting tapes 1 are inscribed in a circular outer metal sheath 4 .

[0070] The low melting point alloy solder 3 is arranged in the gap between the outer metal sheath 4 and the stacked high temperature superconducting tape 1 bundled with the magnetic thin strip 2, the inner wall of the low melting point alloy solder 3 is in contact with the magnetic thin strip 2 wound outside the stacked high temperature superconducting tape 1, and the outer wall of the low melting point alloy solder 3 is in contact with the inner wall of the outer metal sheath 4. The low melting point alloy solder 3 is a low melting point Bi-Sn-In alloy, and the melting point of the low melting point Bi-Sn-In alloy is 78°C.

[0071] The low melting point alloy solder 3 is impregnated by vacuum pressure impregnation of low melting point alloy. On the one hand, during the impregnation process, the molten alloy can penetrate into any gaps between the high temperature superconducting tapes 1, so that the stacked tapes form a whole; on the other hand, the stacked tapes and the outer metal sheath 4 have good mechanical, electrical and thermal connections, improving the thermal stability and mechanical properties of the conductor. In addition, the low melting point alloy solder 3 of the present invention has a low melting point temperature, and the low melting point temperature can avoid damage to the high temperature superconducting tape 1 during the impregnation process.

[0072] Example 2

[0073] Based on the embodiment, this embodiment provides a method for manufacturing a low-loss high-temperature superconducting conductor, comprising the following steps:

[0074] (1) stacking a required number of high-temperature superconducting tapes 1 and wrapping and bundling them with magnetic tapes 2;

[0075] (2) inserting the high temperature superconducting tape 1 wrapped with the magnetic thin tape 2 into the outer metal sheath 4;

[0076] (3) The low melting point alloy solder 3 is heated and melted, and then injected into the gap between the high temperature superconducting tape 1 wrapped and bundled with the magnetic thin strips 2 and the outer metal sheath 4. The molten solder is solidified by a vacuum pressure impregnation process. After solidification, the outer metal sheath 4 and the stacked high temperature superconducting tape 1 wrapped and bundled with the magnetic thin strips 2 are formed into a whole, thereby obtaining a low loss high temperature superconducting conductor.

[0077] The process of vacuum pressure impregnation is as follows: a liquid inlet and a liquid outlet are provided in the outer metal sheath 4. A sealed heatable storage tank is provided at the inlet to heat the low melting point alloy to 100°C, which not only allows the low melting point alloy to melt and maintain fluidity, but also does not damage the high temperature superconducting tape 1. A vacuum pump is provided at the outlet. The space in the metal sheath is evacuated into a vacuum state by the vacuum pump, and the vacuum degree is about 0.1 Pa. At this time, the liquid inlet is opened to fill the low melting point alloy into the gap area between the outer metal sheath 4 and the high temperature superconducting tape 1 stack.

[0078] The solder impregnation between the stacked high-temperature superconducting tapes 1 wound and bound by the outer metal sheath 4 and the magnetic thin strip 2 of the present invention is low-melting-point alloy vacuum pressure impregnation. On the one hand, during the impregnation process, the molten low-melting-point alloy solder 3 can penetrate into any gap between the high-temperature superconducting tapes 1, so that the stacked high-temperature superconducting tapes 1 form a whole; on the other hand, the stacked high-temperature superconducting tapes 1 and the outer metal sheath 4 have good mechanical, electrical and thermal connections, and the thermal stability and mechanical properties of the conductor are improved. In addition, the low-melting-point alloy solder 3 of the present invention has a low melting point temperature, and the low melting point temperature can avoid damage to the high-temperature superconducting tape 1 during the impregnation process.

[0079] Finally, it should be noted that the above specific embodiments are only used to explain in detail the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific implementation method of the present invention and is not used to limit the protection scope of the present invention. Although the present invention is described in detail with reference to the above specific embodiments, ordinary technicians in this field should understand that it is still possible to modify the technical solutions recorded in the above embodiments, or to replace or improve some or all of the technical features therein. These modifications, equivalent replacements and improvements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A low-loss high-temperature superconducting conductor, characterized in that: include: High temperature superconducting tapes (1); A magnetic thin strip (2) is wound and bound outside the high-temperature superconducting strip (1), wherein the magnetic thin strip (2) is an amorphous iron alloy; An outer metal sheath (4) has a gap between it and the high-temperature superconducting tape (1) around which the magnetic thin tape (2) is wrapped and bound; Low melting point alloy solder (3) is arranged in the gap.

2. A low-loss high-temperature superconducting conductor according to claim 1, characterized in that: The high-temperature superconducting tape (1) is a stacked second-generation high-temperature superconducting tape (1).

3. A low-loss high-temperature superconducting conductor according to claim 1, characterized in that: The cross section of the high-temperature superconducting tape (1) is square.

4. The low-loss high-temperature superconducting conductor according to claim 1, characterized in that: The outer metal sheath (4) is made of copper, stainless steel, aluminum or aluminum alloy.

5. The low-loss high-temperature superconducting conductor according to claim 1, characterized in that: The cross section of the outer metal sheath (4) is circular.

6. The low-loss high-temperature superconducting conductor according to claim 1, characterized in that: The low melting point alloy solder (3) is a low melting point Bi-Sn-In alloy.

7. A low-loss high-temperature superconducting conductor according to claim 6, characterized in that: The melting point of the low melting point Bi-Sn-In alloy is 78°C.

8. A method for manufacturing a low-loss high-temperature superconducting conductor according to any one of claims 1 to 7, characterized in that: The following steps are involved: A plurality of high-temperature superconducting tapes (1) are stacked and wrapped and bundled with magnetic thin tapes (2); Inserting a high-temperature superconducting tape (1) wrapped with a magnetic thin tape (2) into an outer metal sheath (4); A low melting point alloy solder (3) is heated and melted, and then injected into the gap between a high temperature superconducting tape (1) wrapped and bound with a magnetic thin tape (2) and an outer metal sheath (4), and the molten solder is solidified by a vacuum pressure impregnation process, and a low loss high temperature superconducting conductor is obtained after solidification.

9. The method for manufacturing a low-loss high-temperature superconducting conductor according to claim 8, characterized in that: The heating melting temperature of the low melting point alloy solder (3) is 90-100°C.

10. The method for manufacturing a low-loss high-temperature superconducting conductor according to claim 8, characterized in that: In the vacuum pressure impregnation process, the vacuum degree of the space inside the outer metal sheath (4) is 0.08-0.15 Pa.

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