Bundle of superconducting wires and superconducting coils

Abstract

In a superconducting coil, the resistance between turns is reliably increased while enabling commutation between superconducting wires within the bundle, thereby suppressing the excitation delay of the coil magnetic field. [Solution] The bundled superconducting wire 15 comprises a superconducting laminate L in which a superconducting layer 4 is formed on a metal substrate 2 via an intermediate layer 3, the periphery of which is covered with a stabilizing layer 5 made of metal, forming a tape shape, and a plurality of superconducting wires 1 bundled together so that the tape surfaces face each other, and an insulating material layer 14 having insulating properties formed on at least one of the front and back tape surfaces which are the outer surfaces of the wire when the bundled plurality of superconducting wires 1 are treated as a single wire.

Description

【Technical Field】 【0001】 Embodiments of the present invention relate to a bundled superconducting wire and a superconducting coil. 【Background Art】 【0002】 With the improvement of superconducting technology, superconducting application devices such as magnetic resonance imaging (MRI) devices, superconducting magnetic energy storage (SMES) devices, or single crystal pulling devices have been put into practical use. These superconducting application devices incorporate a superconducting coil formed by winding a superconducting wire. 【0003】 In recent years, superconducting coils using high-temperature superconducting wires with excellent critical current characteristics in high temperature and high magnetic fields have been developed. As such high-temperature superconducting wires, for example, thin film superconducting wires having a multilayer structure including a tape-shaped metal substrate such as Hastelloy (registered trademark), an intermediate layer such as cerium oxide, an oxide superconducting layer such as YBa2Cu3O7, and a protective metal layer such as silver have been developed. Hereinafter, the thin film superconducting wire will be referred to as a superconducting wire. 【0004】 In a superconducting wire, there are ranges of current, temperature, and magnetic field that can maintain the superconducting state, namely, the so-called critical current, critical temperature, and critical magnetic field. Therefore, although the electrical resistance is almost zero, current cannot flow infinitely. When any critical value is exceeded, a transition phenomenon to the normal conducting state, that is, a quench occurs. The Joule heat generation in the normal conducting transition region due to such a quench instantaneously causes thermal runaway of the superconducting coil and, in the worst case, may lead to burnout. Therefore, protection technology against quenches is essential. 【0005】 For example, there is a technique of a bundled superconducting wire in which a plurality of superconducting wires are bundled, and different bundled superconducting wires are electrically connected to each other, that is, between bundles, to reduce the load factor depending on a site where the local critical current value decreases when the superconducting wire is energized. There is also a technique of a non-insulated superconducting coil in which the entire superconducting coil is impregnated with a conductive resin to electrically connect superconducting wires in different turns. 【Prior Art Documents】 [Patent Documents] 【0006】 [Patent Document 1] Japanese Patent Publication No. 2019-29285 [Patent Document 2] Japanese Patent Publication No. 2022-174411 [Patent Document 3] Japanese Patent Publication No. 2021-168350 [Patent Document 4] Japanese Patent Publication No. 2023-68960 [Overview of the Initiative] [Problems that the invention aims to solve] 【0007】 Uninsulated superconducting coils, which electrically connect superconducting wires of different turns, are effective for quench protection. However, when turns are electrically connected, current flows not only in the circumferential direction but also in the radial direction during excitation, resulting in an excitation delay. To address this issue, a technique is known that involves creating a separation layer between adjacent turns using metal tape, conductive resin, etc., to increase the resistance between turns and suppress the excitation delay. 【0008】 For example, when the separation layer is made of metal tape, a thinner metal tape is preferable from the viewpoint of current density. However, if the metal tape is thin, and the metal tape and the superconducting wire are misaligned in the width direction, the superconducting wires between adjacent turns are more likely to come into contact at the widthwise ends of the superconducting wire, which may cause the inter-turn resistance to become extremely small compared to the design value. 【0009】 Furthermore, when the separation layer is made of conductive resin, one manufacturing method involves applying the conductive resin to the superconducting wire while winding it into a coil shape. Due to the winding pressure when the superconducting wire is wound into a coil shape, the conductive resin before heat curing is pushed out from between the turns, and a smaller amount than the amount applied is placed between the turns. As a result, the superconducting wires between adjacent turns may come into contact, and there is a risk that the resistance between turns cannot be increased in relation to the resistance between bundles. 【0010】 The embodiments of the present invention have been made in consideration of these circumstances, and aim to reliably increase the resistance between turns in a superconducting coil while enabling commutation between superconducting wires within a bundle, thereby suppressing the excitation delay of the coil magnetic field. [Means for solving the problem] 【0011】 The bundled superconducting wire according to an embodiment of the present invention comprises a plurality of superconducting wires bundled together such that the tape surfaces face each other, the periphery of which is covered with a stabilizing layer made of metal, forming a tape shape, and the tape surfaces facing each other, and when the plurality of bundled superconducting wires are treated as a single wire, an insulating material layer having insulating properties is formed on at least one of the front and back tape surfaces which are the outer surfaces of the wire. [Effects of the Invention] 【0012】 According to embodiments of the present invention, in a superconducting coil, it is possible to reliably increase the resistance between turns while enabling commutation of superconducting wires within the bundle, thereby suppressing the excitation delay of the coil magnetic field. [Brief explanation of the drawing] 【0013】 [Figure 1] A perspective view showing a superconducting wire partially fractured. [Figure 2] A cross-sectional view showing the first example of a bundled superconducting wire, which consists of two superconducting wires bundled together. [Figure 3] A cross-sectional view showing a second example of a bundled superconducting wire, which consists of two superconducting wires bundled together. [Figure 4] A perspective view showing a superconducting coil composed of superconducting wires. [Figure 5] A cross-sectional view showing the first example of a superconducting coil fabricated using conventional methods. [Figure 6] A cross-sectional view showing a second example of a superconducting coil fabricated using conventional methods. [Figure 7] A cross-sectional view showing a first example of a bundled superconducting wire according to the first embodiment. [Figure 8]Cross-sectional view showing a second example of the bundled superconducting wire of the first embodiment. [Figure 9] Cross-sectional view showing a third example of the bundled superconducting wire of the first embodiment. [Figure 10] Cross-sectional view showing a fourth example of the bundled superconducting wire of the first embodiment. [Figure 11] Cross-sectional view showing a fifth example of the bundled superconducting wire of the first embodiment. [Figure 12] Cross-sectional view showing the superconducting coil of the first embodiment. [Figure 13] Cross-sectional view showing a first example of the bundled superconducting wire of the second embodiment. [Figure 14] Cross-sectional view showing a second example of the bundled superconducting wire of the second embodiment. [Figure 15] Cross-sectional view showing a third example of the bundled superconducting wire of the second embodiment. [Figure 16] Cross-sectional view showing a fourth example of the bundled superconducting wire of the second embodiment. [Figure 17] Cross-sectional view showing a fifth example of the bundled superconducting wire of the second embodiment. [Figure 18] Cross-sectional view showing a sixth example of the bundled superconducting wire of the second embodiment. 【Embodiments for Carrying Out the Invention】 【0014】 Hereinafter, embodiments of the bundled superconducting wire and the superconducting coil will be described in detail with reference to the drawings. Note that the scales of the illustrated components may be appropriately changed to aid understanding. 【0015】 <� First, conventional general bundled superconducting wires and superconducting coils will be described using FIGS. 1 to 6. \ 【0016】 Reference numeral 1 in FIG. 1 denotes a superconducting wire. This superconducting wire 1 has a tape shape in which a plurality of thin film-like layers are laminated. The superconducting wire 1 has at least a metal substrate 2, an intermediate layer 3, and a superconducting layer 4. Further, the superconducting wire 1 has a stabilizing layer 5, an orientation layer 6, and a protective layer 7. 【0017】 A superconducting layer 4 is formed on a metal substrate 2 via an intermediate layer 3. An orientation layer 6 is provided between the metal substrate 2 and the intermediate layer 3. A protective layer 7 is provided on the superconducting layer 4. These layers are stacked to form a superconducting laminate L. The periphery of the superconducting laminate L is covered with a stabilizing layer 5 made of metal. The protective layer 7 is provided between the superconducting layer 4 and the stabilizing layer 5. 【0018】 The metal substrate 2 is formed from a high-strength metallic material such as stainless steel or a nickel alloy such as Hastelloy®. 【0019】 The intermediate layer 3 is formed from materials such as cerium oxide, magnesium oxide, yttrium oxide, or ytterbium oxide. This intermediate layer 3 functions as a buffer layer between the superconducting layer 4 and the metal substrate 2. 【0020】 The superconducting layer 4 is formed of a Re123-based high-temperature superconductor such as YBCO, DyBCO, or GdBCO. 【0021】 The stabilization layer 5 is formed from a conductive material such as copper or silver. This stabilization layer 5 functions as a bypass, commutating current to it when excessive electricity flows through the superconducting layer 4. 【0022】 The orientation layer 6 is provided for the purpose of aligning the intermediate layer 3. This orientation layer 6 is made of a material such as magnesium oxide. 【0023】 The protective layer 7 is provided to prevent the superconducting layer 4 from degrading due to contact with moisture in the air. This protective layer 7 is made of a material such as silver. In addition, this protective layer 7 also functions as a bypass to commutate current when excessive electricity flows through the superconducting layer 4. 【0024】 Figures 2 and 3 show cross-sectional views of a bundled superconducting wire 9, which is formed by bundling two superconducting wires 1 together. The bundled superconducting wire 9 comprises multiple superconducting wires 1. These superconducting wires 1 are tape-shaped and bundled so that their outer tape surfaces face each other. For example, they are bundled so that the tape surface on the back side of one superconducting wire 1 is in contact with the tape surface on the front side of the other superconducting wire 1. The bundling method includes lamination. 【0025】 In the following explanation, the tape surface (wide tape surface) refers to the two wider surfaces among the four surfaces in a cross-sectional view of a tape-shaped superconducting wire 1. The tape surface is the surface that extends perpendicular to the thickness direction of the superconducting wire 1. A single superconducting wire 1 has two tape surfaces, one on the front and one on the back. Furthermore, two superconducting wires 1 are stacked to form a single bundle of superconducting wires 9, and in this bundle of superconducting wires 9, the two wider surfaces are also referred to as the tape surface. A single bundle of superconducting wires 9 has two tape surfaces, one on the front and one on the back. Note that the two surfaces that are not tape surfaces are sometimes referred to as end surfaces. 【0026】 Each layer within the superconducting wire 1 has an asymmetrical structure with respect to the stacking direction (up and down direction in Figures 2 and 3). The tape surface is distinguished as either the side closer to the superconducting layer 4 or the side closer to the metal substrate 2. 【0027】 There are mainly two ways of bundling the superconducting wires 1. For example, as shown in Figure 2, there is a method in which two superconducting wires 1 are bundled so that the tape surfaces closest to the superconducting layer 4 face each other. Also, as shown in Figure 3, there is a method in which two superconducting wires 1 are bundled so that the tape surface closest to the superconducting layer 4 faces the tape surface furthest from the superconducting layer 4. 【0028】 Figure 4 shows an example of a superconducting coil 8 fabricated by winding superconducting wires 1 so that the tape surfaces face each other and the superconducting wires 1 are stacked on top of each other. The cross-sectional view of the superconducting coil 8 described below is the cross-section S when the superconducting coil 8 is cut in the diametrical direction. 【0029】 Figure 5 shows a cross-sectional view of a superconducting coil 8 made from a conventional superconducting wire 1. This Figure 5 shows a configuration in which a tape-shaped metal tape wire 10 is used as a separation layer. 【0030】 A single turn of the bundled superconducting wire 9 is referred to as one turn T. For example, if the bundled superconducting wire 9 is wound four times, four turns T are formed. The example in Figure 5 shows four turns T formed by winding one bundled superconducting wire 9. In reality, a single superconducting coil 8 is formed by tens to hundreds of turns T. 【0031】 A bundle of superconducting wires 9 and metal tape wires 10 are wound together to form a winding section. The bundle of superconducting wires 9 and the heat transfer member 13 are bonded together via an impregnation material 12. 【0032】 The impregnating material 12 plays a role in securing the heat transfer path and maintaining the shape between the heat transfer member 13 and the bundled superconducting wire 9. The impregnating material 12 consists of a thermosetting resin such as epoxy resin, a thermoplastic resin such as ethylene-methacrylic acid copolymer, and a metallic material such as indium. The impregnating material 12 must be a material that does not crack due to thermal contraction when cooled to extremely low temperatures. 【0033】 The heat transfer member 13 plays a role in assisting heat transfer in the radial direction of the coil. In addition, the heat transfer member 13 plays a role in thermally connecting the superconducting coil 8 to a refrigerator (not shown) or a cooling source of liquid refrigerant (not shown). 【0034】 The heat transfer member 13 is made of a material with high thermal conductivity, such as insulated oxygen-free copper or high-purity aluminum, or a composite material such as glass fiber reinforced plastic. 【0035】 As shown in Figure 5, when the bundled superconducting wire 9 and the metal tape wire 10 are actually wound together, the metal tape wire 10 may be misaligned in the winding axis direction and wound to one side. 【0036】 Furthermore, the superconducting wire 1 may have a dogbone shape in which the thickness of the wire increases from the center in the width direction to the end, i.e., a stabilizing layer 5. Also, the superconducting wire 1 may bend in an arc, and the cross-sectional shape of the superconducting wire 1 is not an ideal rectangle (quadrilateral). Therefore, as shown in Figure 5, for the bundled superconducting wire 9, the stabilizing layers 5 (Figure 1) of the superconducting wire 1 may come into contact with each other at the ends in the width direction without the metal tape wire 10 in between, which may reduce the resistance between turns T. 【0037】 This phenomenon is more likely to occur as the thickness of the metal tape wire 10 decreases. Therefore, in order to reliably increase the resistance between turns T, it becomes necessary to increase the thickness of the metal tape wire 10 and reduce the current density. 【0038】 Furthermore, even in a configuration where insulating tape (not shown) is wound together with the metal tape wire 10, a similar misalignment may occur, potentially preventing a significant increase in resistance between turns T. 【0039】 Figure 6 shows a cross-sectional view of a superconducting coil 8 made from a conventional superconducting wire 1. This Figure 6 shows an embodiment in which a conductive resin 11 is used as a separation layer. 【0040】 A winding section is formed by applying a conductive resin 11 (before heat curing) to the outer surface of a bundle of superconducting wires 9 and winding it. The conductive resin 11 is positioned between adjacent turns T. However, the bundle of superconducting wires 9 needs to be wound under tension to maintain its coil shape, and a compressive force is applied to the bundle of superconducting wires 9 toward the center of the coil. The fluid conductive resin 11 (before heat curing) is pushed out by this compressive force, so the stabilizing layers 5 (Figure 1) of the bundle of superconducting wires 9 come into contact with each other between adjacent turns T, and there is a risk that the resistance between turns T will not be sufficiently large. 【0041】 For these reasons, an uninsulated superconducting coil 8, in which metal tape wires 10 and conductive resin 11 are arranged between adjacent turns T, may not be able to sufficiently increase the resistance between turns T compared to the resistance between the superconducting wires 1 within the bundle. The following embodiment can solve this problem. 【0042】 (First Embodiment) Next, the first embodiment will be described using Figures 7 to 12. Note that components identical to those described above in the conventional general components (Figures 1 to 6) are denoted by the same reference numerals, and redundant explanations are omitted. 【0043】 The first embodiment differs from the conventional general configuration described above in that it is an insulated bundled superconducting wire 15 having an insulating material layer 14 on the outer surface including the entirety of at least one tape surface of the bundled superconducting wire 9. 【0044】 The insulated bundled superconducting wire 15 comprises a plurality of superconducting wires 1 that are tape-shaped and bundled together so that their tape surfaces face each other. Furthermore, when the bundled plurality of superconducting wires 1 are treated as a single wire, the insulated bundled superconducting wire 15 comprises an insulating material layer 14 formed on at least one of the front and back tape surfaces, which are the outer surfaces of this wire. 【0045】 As shown in Figures 7 to 11, an insulating layer 14 is formed on the bundled superconducting wire 9 in the insulated bundled superconducting wire 15. Figure 12 is a cross-sectional view of a superconducting coil 18 formed using the insulated bundled superconducting wire 15. Although Figure 12 illustrates a superconducting coil 18 formed by winding the insulated bundled superconducting wire 15 of Figure 7, the superconducting coil 18 may also be formed by winding the insulated bundled superconducting wire 15 of Figures 8 to 11. 【0046】 The insulating layer 14 is composed of a conventionally known insulating material. It is not particularly limited as long as it is a paintable material, and examples include phenolic resin, epoxy resin, polyamide resin, polyimide resin, polyamide-imide resin, and acrylic resin. 【0047】 However, if the insulating layer 14 is composed of at least one selected from fluororesin, paraffin, grease, and silicone oil, there is a risk that the impregnating material 12 and the insulating layer 14 will separate, and a heat transfer path between the superconducting wire 1 and the heat transfer member 13 may not be secured. 【0048】 Therefore, the insulating layer 14 is composed of at least one selected from phenolic resin, epoxy resin, unsaturated polyester resin, polyamide resin, polyimide resin, polyamide-imide resin, acrylic resin, polyurethane resin, polyethylene resin, and polypropylene resin. 【0049】 Furthermore, in order to prevent a decrease in the critical current value of the superconducting wire 1, it is preferable that the insulating layer 14 be formed by a process that does not require heating above 200°C, and from the viewpoint of increasing current density, it is preferable that the insulating layer 14 be thin. 【0050】 The insulated bundle superconducting wire 15 has an insulating layer 14 on its outer surface, including the entirety of at least one tape surface. In this way, as shown in Figure 12, even if the insulated bundle superconducting wire 15 is misaligned in the winding axis direction, the insulating layer 14 will be positioned between adjacent turns T, thereby ensuring a large resistance between turns T. 【0051】 Figure 12 shows a case where an insulating material layer 14 is provided on the entire outer surface of the bundled superconducting wire 9. However, a configuration in which the insulating material layer 14 is provided on only a part of the outer surface is also acceptable, as long as the insulating material layer 14 is arranged between adjacent turns T. 【0052】 In order to reduce the resistance between superconducting wires 1 within the bundle, it is preferable that no insulating layer 14 is placed at the interface (boundary) between superconducting wires 1 within the insulated bundle of superconducting wires 15, and that the superconducting layers 4 of the superconducting wires 1 be bundled so that the tape surfaces facing each other are facing each other (Figure 2). 【0053】 The superconducting coil 18 is made by winding bundled superconducting wire 9 and impregnating at least a portion of it with an insulating resin. For example, an insulating resin is used as the impregnation material 12. 【0054】 When an insulating resin such as epoxy resin is used for the impregnation material 12, the spaces between turns T are insulated by the insulating material layer 14 and the impregnation material 12. On the other hand, due to the compressive force during winding as described above, the impregnation material 12 does not easily seep between the superconducting wires 1 within the bundle. Therefore, electrical contact is ensured between the superconducting wires 1 within the bundle, enabling commutation and fulfilling the role of reducing the load factor. 【0055】 Furthermore, the superconducting coil 18 may be formed by winding bundled superconducting wire 9 and impregnating at least a portion of it with a conductive resin or metal. For example, a conductive resin 11 (Figure 6) or a conductive metal may be used instead of the impregnating material 12. Also, when conductive materials such as conductive resin 11 or solder are used, the resistance between turns T can be adjusted within the range where the insulating material layer 14 is formed. 【0056】 As shown in Figure 7, in the first example of insulated bundled superconducting wire 15, the insulating layer 14 is formed over the entire outer surface of the bundled superconducting wire 9. The entire outer surface of the bundled superconducting wire 9 refers to the two tape surfaces and the two end faces of the bundled superconducting wire 9. The entire outer surface of the bundled superconducting wire 9 does not include the interfaces where the superconducting wires 1 face each other. 【0057】 Electrical contact occurs only in the portion where the impregnating material 12, which seeps slightly into the bundle, contacts the outer surface of the superconducting wire 1 where the insulating material layer 14 is not formed within the bundle. In this way, the resistance between turns T can be increased. 【0058】 As shown in Figure 8, in the second example of the insulated bundled superconducting wire 15, the insulating material layer 14 is formed only on the two tape surfaces, the front and back, of the bundled superconducting wire 9. In this way, the end face of the bundled superconducting wire 9, where the insulating material layer 14 is not formed, and the impregnating material 12 (Figure 12) come into electrical contact, enabling an electrical connection between the turns T. 【0059】 As shown in Figure 9, in the third example of the insulated bundled superconducting wire 15, the insulating material layer 14 is formed only on the outer surface of one of the superconducting wires 1 in the bundled superconducting wire 9. For example, the insulating material layer 14 is formed on one tape surface and two end faces of one of the superconducting wires 1. In this way, the outer surface of the other superconducting wire 1, which does not have the insulating material layer 14 formed on it, and the impregnating material 12 (Figure 12) come into electrical contact, and the turns T can be electrically connected. 【0060】 As shown in Figure 10, the fourth example of the insulated bundle superconducting wire 15 has another superconducting wire 1 inside the bundle. In other words, one bundle superconducting wire 9 is made up of three superconducting wires 1, and an insulating material layer 14 is formed on the two outer superconducting wires 1. This allows for a further reduction in the load factor. 【0061】 As shown in Figure 11, the fifth example of the insulated bundle superconducting wire 15 includes a metal tape wire 10 within the bundle, the tape wire having a Young's modulus greater than that of the stabilizing layer 5. In other words, the insulated bundle superconducting wire 15 comprises a metal tape wire 10 sandwiched between at least two superconducting wires 1. This improves the electromagnetic resistance performance. 【0062】 Specific manufacturing methods for the insulated bundled superconducting wire 15 of the first embodiment include bundling together a superconducting wire 1 having an insulating material layer 14 on its outer surface, including the entirety of at least one tape surface, and a superconducting wire 1 without an insulating material layer 14. Alternatively, an insulating material layer 14 can be formed on the outer surface of the bundled superconducting wire 9 using a general spray painting or electrostatic painting method. 【0063】 However, when winding the bundled superconducting wires 9 into a coil shape, the lengths of the bundled superconducting wires 1 differ between the inner and outer circumferences of the coil. Therefore, when forming the insulating layer 14, it is preferable to avoid bonding the bundled superconducting wires 1 to each other. 【0064】 In the first embodiment, an insulating layer 14 is placed between adjacent turns T in the superconducting coil 18 (Figure 12), thereby reliably increasing the resistance between turns T. This reliably reduces the current flowing in the radial direction of the coil when the superconducting coil 18 is excited, and suppresses the excitation delay. 【0065】 (Second Embodiment) Next, the second embodiment will be described using Figures 13 to 18. Note that components identical to those in the conventional general components described above (Figures 1 to 6) or the first embodiment (Figures 7 to 12) are denoted by the same reference numerals, and redundant explanations are omitted. 【0066】 Figures 13 to 18 show cross-sectional views of an insulated bundle superconducting wire 17 with a release agent according to the second embodiment. The insulated bundle superconducting wire 17 with a release agent comprises an insulating material layer 14 and a release agent layer 16. 【0067】 The second embodiment differs from the first embodiment in that it is an insulated coated bundle superconducting wire 17 having a release agent layer 16 on at least a portion of its outer surface. In other words, the insulated coated bundle superconducting wire 17 is the insulated coated bundle superconducting wire 15 of the first embodiment with a release agent layer 16 added. This release agent layer 16 is made of at least one material selected from the group consisting of fluororesin, paraffin, grease, and silicone. 【0068】 The multilayer superconducting wire 1 is weak against tensile stress perpendicular to the tape surface, i.e., peeling force. Therefore, there is a risk that interlayer delamination will occur due to thermal stress caused by the difference in thermal shrinkage rates between the impregnating material 12 (Figure 12) and the superconducting wire 1, and the superconducting properties may deteriorate. By providing a release agent layer 16 on a part of the insulating coated bundle superconducting wire 17, when thermal stress occurs, interlayer delamination will occur between the impregnating material 12 and the release agent layer 16, and the peeling force applied to the superconducting wire 1 can be reduced. 【0069】 The release agent layer 16 may be formed on any surface on the outer surface of the multiple superconducting wires 1 in the insulated bundle superconducting wire 17. Preferably, the release agent layer 16 is formed over at least half the area of ​​the tape surface. 【0070】 As shown in Figure 13, the first example of the insulated bundle superconducting wire 17 has an insulating layer 14 and a release layer 16 formed on its entire outer surface. This prevents the insulating layer 14 and the release layer 16 from shifting position when the insulated bundle superconducting wire 17 is wound. 【0071】 As shown in Figure 14, in the second example of the insulated bundle superconducting wire 17, the insulating material layer 14 and the release material layer 16 are formed only on one of the tape surfaces of the outer surface. 【0072】 As shown in Figure 15, in the third example of the insulated bundle superconducting wire 17, an insulating material layer 14 is formed only on one tape surface of the outer surface, and a release material layer 16 is formed only on the other tape surface. 【0073】 As shown in Figure 16, in the fourth example of the insulated bundle superconducting wire 17, an insulating material layer 14 is formed on only one tape surface, and a release material layer 16 is formed between the two superconducting wires 1. 【0074】 As shown in Figure 17, the fifth example of the insulated bundle superconducting wire 17 has another superconducting wire 1 inside the bundle. In other words, one bundle superconducting wire 9 is made up of three superconducting wires 1, and an insulating material layer 14 is formed on the two outer superconducting wires 1. Furthermore, a release material layer 16 is formed between each of the superconducting wires 1. 【0075】 As shown in Figure 18, the sixth example of the insulated bundle superconducting wire 17 has insulating material layers 14 formed on two tape surfaces, front and back. Furthermore, a metal tape wire 10 is placed between the two superconducting wires 1, and a release material layer 16 is formed thereon. For example, the release material layer 16 is formed on the outer surface of the metal tape wire 10. 【0076】 In other words, the sixth example of the insulated bundle superconducting wire 17 includes a release agent layer 16 formed on at least a portion of the metal tape wire 10. This release agent layer 16 is made of at least one material selected from the group consisting of fluororesin, paraffin, grease, and silicone. 【0077】 Furthermore, the release agent layer 16 may separate the impregnating material 12 (Figure 12) and the bundled superconducting wire 9, potentially reducing heat transfer performance. Therefore, as shown in Figures 14 to 18, a portion of the outer surface of the superconducting wire 1 is formed where the release agent layer 16 is not provided. In this way, the portion where the release agent layer 16 is not provided maintains contact between the impregnating material 12 (Figure 12) and the bundled superconducting wire 9, and does not obstruct the heat transfer path from the bundled superconducting wire 9 to the heat transfer member 13 (Figure 12). Also, since the heat transfer path from the end face of the bundled superconducting wire 9 to the heat transfer member 13 has the lowest thermal resistance, it is particularly preferable that the release agent layer 16 be provided on the tape surface of the bundled superconducting wire 9, as shown in Figures 14 and 15. 【0078】 In the second embodiment, the insulated bundle superconducting wire 17 is provided with a release agent layer 16 in part, so that when thermal stress occurs, delamination occurs between the impregnating material 12 (Figure 12) and the release agent layer 16, reducing the peeling force applied to the superconducting wire 1. Therefore, the peeling force transmitted to the superconducting wire 1 is reduced, and deterioration of the superconducting properties can be reliably prevented. 【0079】 Although the present invention has been described above based on the first and second embodiments, a configuration applied in any one embodiment may be applied to another embodiment, or the configurations applied in each embodiment may be combined. 【0080】 According to at least one embodiment described above, an insulating material layer 14 having insulating properties is provided on at least one of the front and back tape surfaces, which are the outer surfaces of the wire. This makes it possible to reliably increase the resistance between turns T in the superconducting coil 18 while allowing the superconducting wires within the bundle to be commutated, thereby suppressing the excitation delay of the coil magnetic field. 【0081】 While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, modifications, and combinations are possible without departing from the spirit of the invention. These embodiments or their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. Where there is a singular noun, it does not exclude plural nouns unless the context clearly indicates otherwise. Furthermore, conjunctions such as "and" and "or" are inclusive unless the context clearly indicates otherwise. [Explanation of symbols] 【0082】 1...Superconducting wire, 2...Metal substrate, 3...Intermediate layer, 4...Superconducting layer, 5...Stabilizing layer, 6...Orientation layer, 7...Protective layer, 8...Superconducting coil, 9...Bundled superconducting wire, 10...Tape wire, 11...Conductive resin, 12...Impregnation material, 13...Heat transfer component, 14...Insulating material layer, 15...Insulated bundled superconducting wire, 16...Release layer, 17...Insulated bundled superconducting wire, L...Superconducting laminate, S...Cross-section.

Claims

[Claim 1] A superconducting laminate, in which a superconducting layer is formed on a metal substrate via an intermediate layer, is surrounded by a stabilizing layer made of metal, forming a tape shape, and multiple superconducting wires are bundled together so that the tape surfaces face each other, When a bundle of the superconducting wires is treated as a single wire, an insulating material layer having insulating properties is formed on at least one of the front and back tape surfaces, which are the outer surfaces of the wire, Equipped with, Bundle of superconducting wires. [Claim 2] It is made of at least one material selected from the group consisting of fluororesin, paraffin, grease, and silicone, and comprises a release agent layer formed on at least a part of the outer surface. The bundled superconducting wire material according to claim 1. [Claim 3] The device comprises a metal tape wire sandwiched between at least two of the superconducting wires, The bundled superconducting wire material according to claim 1. [Claim 4] It comprises at least one material selected from the group consisting of fluororesin, paraffin, grease, and silicone, and includes a release layer formed on at least a portion of the tape wire. The bundled superconducting wire material according to claim 3. [Claim 5] A bundle of superconducting wires according to any one of claims 1 to 4 is wound and at least a portion of it is impregnated with a conductive resin or metal. Superconducting coil. [Claim 6] A bundle of superconducting wires according to any one of claims 1 to 4 is wound and at least a portion of it is impregnated with an insulating resin. Superconducting coil.

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