Superconducting coil device

Abstract

Provided is a superconducting coil device in which, when a current bypass path of a superconducting coil is configured using a conductive adhesive material layer, even if the thickness of the adhesive material layer is reduced, the contact resistivity via the adhesive material layer can be prevented from becoming too small, or the contact resistivity can be adjusted to a desired value or range. A superconducting coil device is provided with: a superconducting coil formed by winding a superconducting wire (1) in a coil shape; and an adhesive material layer (12) that constitutes at least a part of the current bypass path of the superconducting coil, contains an adhesive (12a), and is imparted with electrical conductivity. The adhesive material layer (12) has a resistance drop suppression structure (12b) and (12c) or (12d) that suppresses a drop in contact resistance between the adhesive material layer (12) and the superconducting wire (1) while imparting conductivity to the adhesive material layer (12).

Description

Technical Field

[0001] The present invention relates to a superconducting coil device including a superconducting coil formed by winding a superconducting wire into a coil shape. More specifically, the present invention relates to a superconducting coil device including a current bypass path for the superconducting coil. Background Art

[0002] Superconducting coil devices can generate strong magnetic fields by passing large currents with low losses. Such superconducting coil devices are used in, for example, NMR (nuclear magnetic resonance), MRI (magnetic resonance imaging), magnets for physical experiments, accelerators, maglev railways, nuclear fusion reactors, motors, generators, silicon single crystal pulling devices, aluminum melting devices, etc.

[0003] In a superconducting coil device, a superconducting coil may suddenly or stepwise change from a superconducting state to a normal conducting state. This is called quenching. The temperature of a superconducting coil may rise excessively due to the Joule heat generated during quenching, resulting in damage (burning). Therefore, in a superconducting coil device, it is important to have a technology that suppresses the occurrence of quenching and protects the coil from damage when a quench occurs. This is called quench protection technology.

[0004] This technology system has been established in the coils of low-temperature superconducting (LTS) wires, which have been widely used in practical applications. However, in the coils of high-temperature superconducting (HTS) wires, which are the next-generation materials, such technology is still immature.

[0005] In response to this situation, various technologies (such as the No-insulation method and the Metal as Insulation method) have been proposed to form a current bypass path that electrically connects a plurality of turns in a high-temperature superconducting wire wound into a coil, and research and development have been promoted in this field. Such technologies are disclosed in Patent Document 1 and Non-Patent Document 1, for example.

[0006] Patent Document 1 and Non-Patent Document 1 disclose the Intra-Layer No-Insulation (LNI) method devised by the inventors of the present application. That is, in Patent Document 1 and Non-Patent Document 1, when a solenoid coil having multiple layers arranged in a radial direction is formed using one or more superconducting wires, adjacent layers are insulated from each other by an insulating sheet and multiple turn portions of the solenoid coil are in contact with each other with a copper sheet in each layer. Such a copper sheet forms a current bypass path for detouring the current when a quench occurs.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: International Publication No. 2021 / 172276

[0010] Non-patent literature

[0011] Non-patent document 1: Y.Suetomi et al., "Quench and self-protecting behavior of an intra-layer no-insulation(LNI) REBCO coil at 31.4T", Supercond.Sci.Technol.34(2021)064003(18pp)

[0012] Non-patent document 2: Suetomi et al., "Design Study of Intra-Layer No-Insulation (LNI) REBCO Coil for Conductively Cooled All-HTS 900MHz NMR Magnets", 104th 2022 Fall Meeting of the Society of Low Temperature Engineering and Superconductivity, 2A-a01, 2022.

[0013] Non-patent document 3: Tanaka et al., "Construction of contact resistivity control technology for intra-layer no-insulation (LNI) REBCO coils using conductive epoxy", 104th 2022 Fall Meeting of the Society of Low Temperature Engineering and Superconductivity, 2A-a02, 2022. Summary of the invention

[0014] Problem that the invention aims to solve

[0015] In a superconducting coil device, the value of the contact resistivity (hereinafter also referred to as contact resistivity) between the superconducting wire (the above-mentioned turn portion) and the current bypass path will affect the occurrence of quench and the protection of the coil when quench occurs. For example, if the contact resistivity is too high, the temperature will increase and thermal damage will occur when quench occurs. If the contact resistivity is too low, a large induced current will be generated locally when quench occurs, and mechanical damage will occur due to electromagnetic force. This induced current is caused by the increase in current in the nearby turn portion with strong magnetic coupling in order to compensate for the reduction in magnetic flux caused by the reduction in current when the current in a certain turn portion decreases. In addition, the contact resistivity is defined as, for example, the resistance [Ω] between the superconducting wire and the current bypass path and the contact area (or bonding area) [cm 2 ] product [Ωcm 2 ]. In addition, the contact resistivity defined in this way is sometimes expressed as shunt resistance. Hereafter, the expression contact resistivity is mainly used, but contact resistivity and shunt resistance are synonymous.

[0016] In order to prevent the occurrence of quench or to protect the superconducting coil after quench, it is desirable to adjust the contact resistivity to a desired value or range without making it too small. For example, according to recent studies, in superconducting coils for high magnetic fields, a contact resistivity of 10 mΩcm is sometimes required. 2 Above or 100mΩcm 2 The above contact resistivity (refer to non-patent literature 2, 3). In addition, in order to effectively avoid excessive increase of induced current in other turn parts caused by current reduction in the turn part due to quench, it is also effective to set the value of contact resistivity to an appropriate value according to the location of the superconducting coil in consideration of the strength of magnetic coupling between the turns.

[0017] However, as described above, when the turn portion of the superconducting coil is directly in contact with the metal conductor of the current bypass path (for example, the copper sheet described above), the contact resistivity becomes, for example, 0.1 to 1 mΩcm. 2 Low values ​​around, difficult to adjust.

[0018] In contrast, Non-Patent Document 3 discloses using a conductive epoxy material obtained by mixing a conductive filler in an epoxy resin as a contact interface with a superconducting coil. Based on this disclosure, for example, it is conceivable to electrically connect multiple turns of a superconducting coil to the copper sheet via the conductive epoxy material.

[0019] However, in this case, if the thickness of the conductive epoxy is set to a small value (for example, less than 30 μm or less than 20 μm), more parts of the superconducting wire directly contact the copper sheet will be generated. This is caused by the unevenness of the surface shape of the superconducting wire and the copper sheet, and is a phenomenon discovered by the inventors. As a result, the contact resistivity of the superconducting wire and the copper sheet via the conductive epoxy becomes too low or has a large deviation, making it difficult to adjust the contact resistivity to a desired value or range. On the other hand, in order to prevent the contact resistivity from becoming too small and adjusting it to a desired value or range, it is possible to consider increasing the thickness of the conductive epoxy, but in this case, it is possible that the superconducting coil device is enlarged or the conductive epoxy becomes a factor that hinders cooling.

[0020] Therefore, an object of the present invention is to provide the following technology: when a current bypass path is formed using a conductive adhesive material layer, even if the thickness of the adhesive material layer is thinned (for example, even if it is set to less than 30 μm or less than 20 μm), the contact resistivity through the adhesive material layer can be prevented from becoming too small, or the contact resistivity can be adjusted to a desired value or range.

[0021] Solutions for solving problems

[0022] In order to achieve the above-mentioned object, the superconducting coil device of the present invention comprises:

[0023] a superconducting coil formed by winding a superconducting wire into a coil; and

[0024] an adhesive material layer, which constitutes at least a portion of the current bypass path of the superconducting coil, contains an adhesive and is imparted with electrical conductivity,

[0025] The adhesive layer has a resistance reduction suppressing structure that provides conductivity to the adhesive layer and suppresses a reduction in contact resistance between the adhesive layer and the superconducting wire.

[0026] Effects of the Invention

[0027] According to the present invention, the adhesive layer containing a binder has a resistance reduction suppressing structure that not only imparts conductivity to the adhesive layer but also suppresses a reduction in contact resistance between the adhesive layer and the superconducting wire, thereby preventing the contact resistivity through the adhesive layer from becoming excessively low unexpectedly. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a perspective view showing a cross section of the superconducting coil device according to the first embodiment of the present invention.

[0029] Figure 2 It is an exploded explanatory diagram of the winding structure of the superconducting wire 1.

[0030] Figure 3 yes Figure 1 An enlarged view of the region R1 surrounded by the dotted line in FIG.

[0031] Figure 4 yes Figure 3 The partially enlarged view in FIG. 1 shows the cross-sectional structure of the superconducting wire.

[0032] Figure 5A yes Figure 3 A partially enlarged view schematically shows a configuration example 1 of the adhesive material layer.

[0033] Figure 5B yes Figure 3 A partial enlarged view schematically shows a configuration example 2 of the adhesive material layer.

[0034] Figure 6 Graph showing contact resistivity measured for the adhesive layer of each of Examples 1 and 2 and Reference Examples 1 and 2. FIG.

[0035] Fig. 7A Graph showing the contact resistivity measured for the adhesive layer of Example 3.

[0036] Figure 7B This is a graph showing the current-voltage characteristics measured for the adhesive layer of Example 3.

[0037] Figure 8 This is a table showing the experimental results related to the insulating filler of the adhesive layer.

[0038] Fig. 9A The figure shows the change in contact resistivity when the superconducting coil is repeatedly changed between a superconducting state and a normal temperature state.

[0039] Fig. 9B The graph shows the transition of the critical current value when the superconducting coil is repeatedly changed between the superconducting state and the normal temperature state.

[0040] Fig. 10A yes Figure 1 2 is an enlarged view of a region R2 surrounded by a dotted line in FIG. 1 , but shows the situation of the second embodiment.

[0041] Fig. 10B yes Figure 1 2 is an enlarged view of a region R3 surrounded by a dotted line in FIG. 1 , but shows the situation of the second embodiment.

[0042] Fig.11A yes Figure 1 2 is an enlarged view of a region R2 surrounded by a dotted line in FIG. 1 , but shows the situation of the first embodiment.

[0043] Fig. 11B yes Figure 1 2 is an enlarged view of a region R3 surrounded by a dotted line in FIG. 1 , but shows the situation of the first embodiment.

[0044] Fig.12 It is a perspective view showing a cross section of a superconducting coil device according to a third embodiment of the present invention.

[0045] Fig.13 yes Fig.12 An enlarged view of the area R4 surrounded by the dotted line in FIG.

[0046] Fig.14A yes Fig.12 An enlarged view of the area R5 surrounded by the dotted line in FIG.

[0047] Fig. 14B yes Fig.12 This is an enlarged view of a region R5 surrounded by a dotted line, but shows another configuration example.

[0048] Fig.15 yes Fig.12 This is an enlarged view of the region R4 surrounded by the dotted line, but shows another configuration example.

[0049] Fig.16 yes Fig.12 This is an enlarged view of the region R4 surrounded by the dotted line, but shows another configuration example.

[0050] Fig.17 yes Fig.12 This is an enlarged view of the region R4 surrounded by the dotted line, but shows another configuration example.

[0051] Fig.18A A configuration example of a cross section of a bundle-type superconducting wire according to Modification Example 1 is shown.

[0052] Fig.18B Another configuration example of the cross section of the bundle-type superconducting wire according to Modification 1 is shown.

[0053] Fig.19A yes Figure 1This is an enlarged view of a region R1 surrounded by a dotted line, but shows a configuration example of Modification Example 2.

[0054] Fig.19B yes Fig.12 This is an enlarged view of a region R4 surrounded by a dotted line, but shows a configuration example of Modification Example 2.

[0055] Fig. 20A yes Figure 3 , but schematically shows an example of the structure of the adhesive layer of Modification Example 5.

[0056] Fig. 20B This is an enlarged cross-sectional view showing another configuration example of the fiber body in Modification Example 5.

[0057] Fig. 20C yes Figure 5A The enlarged view of the modification example 5 is shown. Fig. 20B The situation of the fibrous body.

[0058] Fig.21 The following shows the measurement results of the contact resistivity (shunt resistance) when a metal mesh is used as the fiber body.

[0059] Fig. 22 The following shows the change in contact resistivity when the superconducting coil is repeatedly changed between the superconducting state and the normal temperature state in the case of using the fiber body of Modification Example 5.

[0060] Description of Reference Numerals

[0061] 1Superconducting wire

[0062] 1a Superconducting layer

[0063] 1b substrate

[0064] 1c Stabilization layer

[0065] 1A Bundle-type superconducting wire

[0066] 2 Winding frame

[0067] 3. Retaining components

[0068] 10 Superconducting coil device

[0069] 11 Superconducting coil

[0070] 12 Adhesive material layer

[0071] 12a Adhesive

[0072] 12b Conductive filler

[0073] 12b1 Type 1 conductive filler

[0074] 12b2 Second conductive filler

[0075] 12c Insulating filler

[0076] 12d fiber body

[0077] 12d1 fiber

[0078] 12f Local area

[0079] 13 Conductor

[0080] 14 Interlayer insulation

[0081] 15 Turn-to-turn insulation

[0082] 16 Interlayer conductor part

[0083] 17 Interlayer insulation

[0084] 18 Connection

[0085] C Center axis

[0086] T turn section

[0087] Ta interlayer turn part. DETAILED DESCRIPTION

[0088] [Summary of the Invention]

[0089] A superconducting coil device according to one embodiment of the present invention comprises: a superconducting coil formed by winding a superconducting wire into a coil shape; and an adhesive layer constituting at least a portion of a current bypass path of the superconducting coil, containing an adhesive and imparted with conductivity. The adhesive layer has a resistance reduction suppressing structure that not only imparts conductivity to the adhesive layer but also suppresses a reduction in contact resistance (contact resistivity) between the adhesive layer and the superconducting wire.

[0090] This resistance reduction suppressing structure includes a conductive filler and an insulating filler in the first to third embodiments described below, etc. Alternatively, the resistance reduction suppressing structure includes a fiber body (eg, a metal mesh) formed of conductive fibers in Modification 5 described below.

[0091] The current bypass path of the superconducting coil is a path (e.g., a path that makes the current detour) through which the current flows in a manner that avoids a certain portion of the superconducting wire forming the superconducting coil when the current returns to a normal conductive state and generates resistance. In the current bypass path, the current passes through the adhesive material layer from one side in the thickness direction of the adhesive material layer to the other side in the thickness direction of the adhesive material layer.

[0092] In one configuration, as shown in the first to third embodiments described later, the current bypass path is a path that electrically connects at least a plurality of different portions (hereinafter referred to as a plurality of portions) in a superconducting wire forming a superconducting coil. When a quench occurs in the superconducting coil and a portion between a first portion and a second portion included in the plurality of portions in the superconducting wire returns to a normal conductive state and generates resistance, the current does not flow through the portion but flows through the current bypass path from the first portion to the second portion. In the first to third embodiments described later, the plurality of portions are, for example, a plurality of turn portions in one layer (a coil layer described later) of the superconducting coil, or a turn portion located at the end of each of two coil layers adjacent to each other.

[0093] In other configurations, as shown in Modifications 1 and 2 described later, in the current bypass path of the superconducting coil, when a quench occurs in any one of the plurality of locations in the superconducting wire and the superconducting wire returns to a normal conductive state and generates resistance, the current flows to another location among the plurality of locations through the current bypass path in a manner avoiding the location. In Modifications 1 and 2 described later, the plurality of locations are a plurality of superconducting wires constituting a bundle-type superconducting wire.

[0094] The current bypass path may be provided in the superconducting coil. Such a current bypass path is provided between adjacent coil layers constituting the superconducting coil in the first to third embodiments described below, and is provided between a plurality of superconducting wires constituting a bundled superconducting wire in the first and second modifications described below.

[0095] According to such a superconducting coil device, the adhesive layer constituting the current bypass path contains not only an adhesive and a conductive filler but also an insulating filler in the first to third embodiments described later. The insulating filler functions as a spacer in the adhesive layer. Therefore, even if the adhesive layer is formed to be thinner, the above-mentioned spacer prevents the formation of a portion where low-resistance portions (for example, the turn portion and the conductor portion of the superconducting wire described later) on both sides of the thickness direction of the adhesive layer are in direct contact with each other. Thus, by having an adhesive layer in at least a portion of the current bypass path, it is possible to prevent the contact resistivity through the adhesive layer from becoming too small. In this way, a resistance reduction suppression structure that not only imparts conductivity to the adhesive layer but also suppresses the reduction of the contact resistance (contact resistivity) between the adhesive layer and the superconducting wire is constituted by the conductive filler and the insulating filler. The resistance reduction suppression structure in the case of the modification example 5 will be described later. In addition, the adhesive layer can be arranged at one end, both ends, or in the middle of the current bypass path in the direction of current flow.

[0096] In addition, the adhesive material layer may contain a plurality of conductive fillers having different electrical conductivities as the conductive filler. That is, the plurality of conductive fillers are formed of materials having different electrical conductivities. In this case, by adjusting the mixing ratio of the plurality of conductive fillers having different electrical conductivities, the contact resistivity with the superconducting wire can be adjusted to a desired value or a desired range.

[0097] [First embodiment]

[0098] Figure 1 1 is a perspective view showing an example of a cross section of the superconducting coil device 10 according to the first embodiment of the present invention. The cross section is a cross section taken along a virtual plane including the central axis C of the superconducting coil 11 provided in the superconducting coil device 10. In addition, a cross section of the superconducting coil device 10 taken along any virtual plane including the central axis C may be the same as the cross section of the superconducting coil device 10. Figure 1 Same cross section.

[0099] Superconducting coil device 10 is a device that generates a magnetic field by current flowing through superconducting coil 11, and is used in, for example, NMR, MRI, magnets for physical experiments, accelerators, maglev railways, nuclear fusion reactors, motors, generators, silicon single crystal pulling devices, aluminum melting devices, etc.

[0100] <Structure of superconducting coil>

[0101] The superconducting coil 11 is formed by winding the superconducting wire 1 into a coil shape. In the first embodiment, the superconducting wire 1 is wound around the central axis C (e.g., in a coil shape) while being transferred in a direction parallel to the central axis C of the superconducting coil 11 (hereinafter also referred to as the axial direction). Such a superconducting coil 11 can be formed as follows. Figure 1 The solenoid coil (cylindrical coil) may have other shapes as in the configuration example of , and the other shapes may be, for example, a racetrack shape or a D-shape, but are not limited thereto.

[0102] like Figure 1 As shown in FIG. 1 , the superconducting wire 1 can be wound on the outer peripheral surface of the winding frame 2. The central axis of the winding frame 2 can be consistent with the central axis C of the superconducting coil 11. Figure 1 The shape shown may be cylindrical, but may be other shapes as long as the superconducting wire 1 can be wound into a coil shape on its outer circumference. Figure 1 In the embodiment, holding members 3 for holding the axial ends of the superconducting coil 11 are attached to both axial ends of the winding frame 2 .

[0103] In addition, the outer peripheral surface of the winding frame 2 can be formed of a material having electrical insulation properties. In the case where this is not the case, although the illustration is omitted, the superconducting wire 1 can be wound on the outer peripheral surface of the winding frame 2, for example, via a sheet-like member having electrical insulation properties. In addition, the retaining member 3 can be formed of a material having electrical insulation properties. In the retaining member 3, the surface that contacts the axial end of the superconducting coil 11 can be formed of a material having electrical insulation properties. In the case where this is not the case, although the illustration is omitted, the retaining member 3 retains the axial end of the superconducting coil 11 via a sheet-like member having electrical insulation properties. In addition, in the following figures, the area shown as the winding frame 2 is assumed to be an electrically insulating portion for description.

[0104] Figure 2 1 is an exploded view illustrating the winding structure of the superconducting wire 1. Figure 2 As shown, a superconducting wire 1 is wound around a central axis C while being transferred in an axial direction as a coil layer (hereinafter also referred to as a coil layer) in a radial direction (hereinafter also referred to as a radial direction) of a superconducting coil 11, and the superconducting coil 11 has a plurality of coil layers adjacent to each other in the radial direction. Figure 2 The first to third coil layers among the plurality of (for example, a large number of) coil layers are shown separated from each other. Figure 1 The common central axis C is shown.

[0105] A plurality of coil layers are formed by a superconducting wire 1. That is, the superconducting wire 1 is extended in a manner of repeatedly performing the following process: in one coil layer (the innermost layer in the radial direction), it is extended around the central axis C while transferring axially from one axial end to the other axial end, and then transferred radially outward to the next coil layer, and in the next coil layer (the second layer), it is extended around the central axis C while transferring axially from the other axial end to one axial end, and then transferred radially outward to the next coil layer (the third layer). Here, the superconducting wire 1 may be a continuous superconducting wire, or it may be a plurality of superconducting wires connected in series. In the latter case, the superconducting wire 1 may have a plurality of superconducting wires connected in series, and a connection portion between these superconducting wires. The connection portion may be formed by welding, heat treatment, etc.

[0106] exist Figure 2In the figure, each dotted arrow shows the position where the superconducting wire 1 is transferred from the coil layer on the inner side in the radial direction to the next coil layer on the outer side in the radial direction (hereinafter also referred to as the transfer position). In the case where multiple coil layers are formed by the superconducting wire 1 formed by connecting multiple superconducting wires in series, at each transfer position, the end of the superconducting wire forming the coil layer on the inner side in the radial direction and the end of the superconducting wire forming the coil layer on the outer side in the radial direction can be connected to each other through a connection formed by welding, heat treatment, etc. In addition, the number of coil layers formed by the superconducting wire 1 can be 2 or 3. In this case, the above repetition is until the second coil layer or the third coil layer. In addition, the number of coil layers can also be 4 or more.

[0107] Figure 3 yes Figure 1 The enlarged view of the region R1 surrounded by the dotted line in FIG. 1 shows the schematic structure of this portion.

[0108] The superconducting wire 1 is configured to include a superconducting layer 1a formed of a superconducting material. The superconducting layer 1a may also be a high-temperature superconducting layer 1a. Here, the "high-temperature superconducting layer 1a" may generally be a wire composed of a superconducting material having a critical temperature Tc (transition temperature) of about 25K or more (e.g., higher than 25K) in the absence of a magnetic field. For example, the high-temperature superconducting layer 1a may be a wire composed of a superconducting material such as an oxide superconductor including a copper-based superconductor or an iron-based superconductor.

[0109] More specifically, the high temperature superconducting layer 1a may be a wire made of a yttrium-based superconductor or a bismuth-based superconductor, or may be made of a wire having a chemical formula of YBa2Cu3O 7-δ ReBa2Cu3O 7-δ 、Contains Bi2Sr2CaCu2O 8+δ (Bi2212), Bi2Sr2Ca2Cu3O 10+δ Bi2Sr2Ca (Bi2223) n- 1Cu n O 4+2n+δ In addition, a wire material in which oxide nanoparticles of zirconium, dysprosium, etc. are precipitated in the above-mentioned wire material composed of a yttrium-based superconductor or a bismuth-based superconductor to improve the critical current characteristics, or a wire material in which a part is replaced with other elements can be used as the high-temperature superconducting layer 1a. A wire material composed of a material having a superconducting transition temperature exceeding 25K, such as MgB2, which is a metal-based superconductor, can also be used as the high-temperature superconducting layer 1a.

[0110] Figure 4 yes Figure 3A partially enlarged view shows the cross-sectional structure of the superconducting wire 1. For mechanical reinforcement and electrical stabilization, the superconducting wire 1 may have a substrate layer 1b and a stabilization layer 1c in addition to the superconducting layer 1a. The superconducting layer 1a is stacked on the substrate layer 1b, for example, via an intermediate layer (not shown). The substrate layer 1b may be formed of a metal (for example, Hastelloy). The intermediate layer may have the function of improving the crystal orientation of the superconducting layer 1a and the function of inhibiting the reaction between the superconducting layer 1a and the metal substrate 1b. The stabilizing layer 1c may be stacked on the superconducting layer 1a, for example, via a silver protective layer (not shown). The silver protective layer may be located on the surface of the superconducting layer 1a on the opposite side of the intermediate layer. For example, as Figure 4 As shown, the stabilizing layer 1c may be provided to cover the entire periphery of the substrate layer 1b and the superconducting layer 1a (and the intermediate layer and the silver protective layer not shown). The stabilizing layer 1c is formed of copper, for example.

[0111] <Configuration related to current bypass path>

[0112] like Figure 3 As shown, superconducting coil device 10 includes conductive adhesive layer 12 in each coil layer that contacts multiple turns T of superconducting coil 11. Adhesive layer 12 forms a current bypass path that electrically connects multiple turns T to each other.

[0113] As described later, the adhesive layer 12 includes an electrically insulating adhesive 12a (adhesive material), and has electrical conductivity due to the conductive filler 12b being mixed in the adhesive 12a. The more detailed structure of the adhesive layer 12 will be described later.

[0114] In the present embodiment, the superconducting coil device 10 further includes a conductor portion 13 and an interlayer insulating portion 14 in each coil layer. That is, an adhesive material layer 12, a conductor portion 13, and an interlayer insulating portion 14 are provided corresponding to each coil layer. The adhesive material layer 12, the conductor portion 13, and the interlayer insulating portion 14 can each be formed into a layer or sheet having a thin thickness in the radial direction. In addition, in the present embodiment, the adhesive material layer 12, the conductor portion 13, and the interlayer insulating portion 14 can each extend in the circumferential direction and axial direction (hereinafter also referred to as the circumferential direction and the axial direction, respectively) of the superconducting coil 11 along the corresponding coil layer. Such an adhesive material layer 12, the conductor portion 13, and the interlayer insulating portion 14 can each extend over the entire corresponding coil layer. For example, the adhesive material layer 12, the conductor portion 13, and the interlayer insulating portion 14 can each be formed in a manner of going around in the circumferential direction (for example, in a cylindrical shape). Figure 3 In the example of FIG. 1 , between each pair of adjacent coil layers, the adhesive layer 12, the conductor portion 13, and the interlayer insulating portion 14 are provided in order from the radial inside to the radial outside. However, the order may be reversed.

[0115] In addition, the adhesive material layer 12 also has the function of bonding the superconducting wire 1 and the conductor part 13 extending around the central axis C in each coil layer with an adhesive 12a described later. In addition, the adhesive material layer 12 can be in contact with all the turn parts T in the corresponding coil layer. Such an adhesive material layer 12 can extend continuously in the axial direction and the circumferential direction over the substantially entire coil layer.

[0116] The conductor part 13 is formed of a conductive material, such as copper, platinum, gold, silver, brass, stainless steel or other metals. The conductor part 13 is provided to be electrically connected to a plurality of (all) turn parts T of the corresponding coil layer via the adhesive material layer 12 .

[0117] Therefore, adhesive layer 12 corresponding to each coil layer and conductor portion 13 corresponding to the coil layer form a current bypass path that electrically connects the turns of superconducting coil 11 in the coil layer. In this way, a current bypass path is formed for each coil layer.

[0118] The current bypass path formed by the adhesive material layer 12 and the conductor portion 13 is, for example, the following path: Figure 3 As shown by the dotted arrow, in the corresponding coil layer, from any turn portion T through the adhesive material layer 12 to the conductor portion 13, advance axially in the conductor portion 13, from the conductor portion 13 through the adhesive material layer 12 to reach another (for example, adjacent) turn portion T.

[0119] The electrical conductivity of the adhesive layer 12 may be lower than the electrical conductivity of the conductor portion 13. In addition, the electrical resistance per unit length in the direction perpendicular to the thickness direction of the adhesive layer 12 (e.g., the axial direction) may be lower than the electrical resistance per unit length of the superconducting wire 1 in the normal conductive state (the unit length in the direction in which the superconducting wire 1 extends) and higher than the electrical resistance per unit length of the superconducting wire 1 in the superconducting state. Thus, when a quench occurs in the superconducting coil 11, the current of the superconducting coil 11 flows through the above-mentioned current bypass path due to the electrical resistance generated in the superconducting coil 11 that returns to the normal conductive state. As a result, the burning of the superconducting coil 11 is prevented.

[0120] Interlayer insulating portion 14 corresponding to each coil layer is provided between conductor portion 13 and a coil layer (superconducting wire 1 ) adjacent to the coil layer in the radial direction so that conductor portion 13 corresponding to the coil layer does not contact the coil layer (superconducting wire 1 ) adjacent to the coil layer in the radial direction.

[0121] <Composition of adhesive layer>

[0122] Figure 5A and Figure 5B yes Figure 3 A partial enlarged view of . Figure 5A1 is a diagram schematically showing a configuration example 1 of the adhesive material layer 12. Figure 5B It is a diagram schematically showing a second configuration example of the adhesive material layer 12 .

[0123] like Figure 5A or Figure 5B As shown, the adhesive material layer 12 includes an adhesive 12a, a conductive filler 12b, and an insulating filler 12c as main components. That is, the adhesive material layer 12 is an adhesive material layer formed by mixing the conductive filler 12b and the insulating filler 12c with the adhesive 12a. The adhesive 12a may be an adhesive having electrical insulation, but since the conductive filler 12b has electrical conductivity, the adhesive material layer 12 has electrical conductivity in the thickness direction of the adhesive material layer 12 (in the first embodiment, the radial direction of the superconducting coil 11). On the other hand, according to experiments, the adhesive material layer 12 can be configured to have substantially no electrical conductivity in the direction orthogonal to the thickness direction of the adhesive material layer 12 (in the first embodiment, the axial direction and circumferential direction of the superconducting coil 11). The insulating filler 12c has electrical insulation. The insulating filler 12c may be magnesium oxide (MgO). MgO as the insulating filler 12c not only has both insulation and thermal conductivity, but also has a Mohs hardness of 5.5 which is not too large, thereby preventing particles from being crushed or bitten into the superconducting wire 1 due to pressure. However, the material of the insulating filler 12c is not limited to MgO, and other materials may be used for the insulating filler 12c. The adhesive 12a is, for example, epoxy resin, but is not limited thereto. In addition, the adhesive material layer 12 may be composed of only the adhesive 12a, the conductive filler 12b, and the insulating filler 12c, or may contain components other than the above main components.

[0124] The mass ratio of the insulating filler 12 c to the binder 12 a may be, for example, 3% or more and less than 30%, 5% or more and 25% or more, or 5% or more and 20% or less, but is not limited to these ranges.

[0125] The average particle size of the insulating filler 12c may be larger than that of the conductive filler 12b, but is not limited thereto. In the present application, the average particle size may be represented by a circle equivalent diameter obtained by microscopy or a sphere equivalent diameter obtained by light scattering.

[0126] In addition, the average particle size of the conductive filler 12b can be smaller than the thickness of the adhesive layer 12. In this case, the average particle size of the conductive filler 12b can be the same level as the thickness of the adhesive layer 12 (for example, about 2 / 3, more than 1 / 2, more than 1 / 3, or more than 1 / 5 of the thickness of the adhesive layer 12). Similarly, the average particle size of the insulating filler 12c can be smaller than the thickness of the adhesive layer 12. In this case, the average particle size of the insulating filler 12c can be the same level as the thickness of the adhesive layer 12 (for example, about 2 / 3, more than 1 / 2, more than 1 / 3, or more than 1 / 5 of the thickness of the adhesive layer 12). For example, the thickness of the adhesive layer 12 can be 30 μm or less. The lower limit of the thickness of the adhesive layer 12 is a thickness that can prevent the conductor portion 13 from directly contacting the above-mentioned turn portion T (i.e., the superconducting wire 1) and causing a short circuit. For example, the lower limit of the thickness of the adhesive layer 12 is about 20 μm (18 μm in one example), but the thickness is not limited to this value and can be changed appropriately.

[0127] In addition, for example, the average particle diameter of the conductive filler 12b and the average particle diameter of the insulating filler 12c may each be in the range of 5 μm to 25 μm, 10 μm to 20 μm, or 15 μm to 20 μm, but are not limited to these ranges.

[0128] In addition, in the present embodiment, the conductive filler 12b and the insulating filler 12c are powdered fillers. However, in the first embodiment, the second embodiment, or the third embodiment, a fibrous conductive filler may be used instead of the powdered conductive filler 12b. Similarly, in the first embodiment, the second embodiment, or the third embodiment, a fibrous insulating filler may be used instead of the powdered insulating filler 12c.

[0129] · Configuration Example 1

[0130] like Figure 5A As shown, in Configuration Example 1, the type of the conductive filler 12b mixed in the adhesive layer 12 is one. That is, as the conductive filler 12b mixed in the adhesive layer 12, there is only the conductive filler 12b of the same conductive material (for example, copper).

[0131] · Example 2

[0132] like Figure 5B As shown, in Configuration Example 2, the conductive filler 12b mixed in the adhesive material layer 12 is of multiple types. That is, the conductive filler 12b mixed in the adhesive material layer 12 includes multiple types of conductive fillers having different electrical conductivities. Figure 5BIn the example of FIG. 1 , as the plurality of types of conductive fillers 12 b , a first type of conductive filler 12 b 1 and a second type of conductive filler 12 b 2 are mixed in the adhesive layer 12 .

[0133] In one example, the first conductive filler 12b1 is made of copper (Cu), and the second conductive filler 12b2 is made of graphite (C). The number of the conductive fillers 12b mixed in the adhesive layer 12 is not limited to two, but may be three or more.

[0134] <Configuration related to insulation between adjacent turns>

[0135] The superconducting coil device 10 includes an inter-turn insulating portion 15 provided between each pair of axially adjacent turn portions T in each coil layer to prevent the turn portions T from contacting each other in the axial direction. The inter-turn insulating portion 15 is formed of a material having electrical insulation properties.

[0136] The inter-turn insulating portion 15 has a linear shape extending around the central axis C along the superconducting wire 1. That is, the inter-turn insulating portion 15 may have a shape in which the superconducting wire 1 is transferred in the axial direction while being wound around the central axis C. More specifically, the inter-turn insulating portion 15 may extend along the superconducting wire 1 around the central axis C in the entire long side direction of the superconducting wire 1 (the entire direction in which the superconducting wire 1 extends around the central axis C) while being in contact with the superconducting wire 1 in the axial direction. Such an inter-turn insulating portion 15 may be a linear member extending around the central axis C. For example, the inter-turn insulating portion 15 may be a linear member in which the outer periphery of the copper wire is entirely covered with an electrically insulating material.

[0137] <Effects of the First Embodiment>

[0138] According to the first embodiment, the following effects (1) to (6) can be obtained.

[0139] (1) According to the superconducting coil device 10 of the present embodiment, the current bypass path is formed by the adhesive layer 12 containing not only the adhesive 12a and the conductive filler 12b but also the insulating filler 12c. The insulating filler 12c functions as a spacer in the adhesive layer 12. That is, the above-mentioned spacer prevents the conductor portion 13 from directly contacting (short-circuiting) with the superconducting wire 1. Therefore, even if the thickness of the adhesive layer 12 is reduced, the contact resistivity between the turn portion T of the superconducting coil 11 and the current bypass path (adhesive layer 12) can be prevented from becoming too small, and for example, the contact resistivity can be made to be a relatively large value.

[0140] (2) In the above-mentioned configuration example 2, by adjusting the mixing ratio of the plurality of conductive fillers 12b1 and 12b2 having different conductivities, the conductivity of the adhesive material layer 12 can be adjusted to a desired value or a desired range. That is, for example, as in the later-described embodiment 3, by changing the mass ratio of the plurality of conductive fillers 12b1 and 12b2 having different conductivities, the contact resistivity can be changed according to the change. Thus, the conductivity of the adhesive material layer 12 can be adjusted to a desired value or a desired range.

[0141] (3) The conductor portion 13 extends in the axial direction adjacent to the plurality of turn portions T arranged in the axial direction, and is electrically connected to the plurality of turn portions T via the adhesive layer 12. With such an adhesive layer 12 and the conductor portion 13, a current bypass path having the above-mentioned effects (1) and (2) can be formed.

[0142] (4) The inter-turn insulating portion 15 is provided between each pair of axially adjacent turn portions T to prevent the turn portions T from contacting each other in the axial direction. Thus, the current bypass path formed by the adhesive material layer 12 and the conductor portion 13 can function appropriately. For example, even when the contact resistivity of the current bypass path with respect to the turn portion T is set high, the current can flow from the turn portion T to the current bypass path when a quench occurs.

[0143] (5) With respect to each coil layer, the adhesive material layer 12 extends in the axial direction and the circumferential direction in a manner in contact with the outer peripheral surface of the plurality of (all) turn portions T of the superconducting wire 1 forming the coil layer, and the conductor portion 13 extends in the axial direction and the circumferential direction in a manner in contact with the outer peripheral surface (the entire outer peripheral surface) of the adhesive material layer 12. Therefore, the cooling of the superconducting wire 1 can be promoted by heat transfer from the superconducting wire 1 to the conductor portion 13 via the adhesive material layer 12. In this regard, in the adhesive material layer 12, the heat of the superconducting wire 1 can be transferred to the conductor portion 13 mainly through the conductive filler 12b and the insulating filler 12c of the adhesive material layer 12. In this regard, for example, the thermal conductivity of MgO as the insulating filler 12c is relatively high.

[0144] (6) The plurality of (all) turns of the superconducting wire 1 of each coil layer are mechanically bonded and integrated by the adhesive material layer 12 mixed with the conductive filler 12b and the insulating filler 12c. As a result, the superconducting coil structure can be tenaciously maintained against the strong electromagnetic force generated when a current flows through the superconducting coil 11 and a magnetic field is generated, and damage and property degradation due to collapse, buckling, peeling, etc. of the superconducting wire 1 can be prevented.

[0145] (Examples 1 and 2: Case where there is only one kind of conductive filler)

[0146] In each of Examples 1 and 2 and Reference Examples 1 and 2, an adhesive layer was formed, and the contact resistivity of the adhesive layer with respect to the superconducting wire was measured.

[0147] Examples 1 and 2 correspond to the case of Configuration Example 1 described above.

[0148] The adhesive layer 12 of Example 1 is a layer obtained by mixing graphite powder as a conductive filler 12b and magnesium oxide MgO powder as an insulating filler 12c with epoxy resin binder 12a. In Example 1, the content of MgO in the entire adhesive layer 12 is 5 wt%.

[0149] The adhesive layer 12 of Example 2 is an adhesive layer formed by mixing copper powder as a conductive filler 12b and magnesium oxide MgO powder as an insulating filler 12c with epoxy resin binder 12a. In Example 2, the content of MgO relative to the entire adhesive layer 12 is also 5 wt%.

[0150] Reference Examples 1 and 2 correspond to the case where the adhesive layer is formed without using an insulating filler.

[0151] The adhesive layer of Reference Example 1 is an adhesive layer in which graphite powder as a conductive filler is mixed with an epoxy resin binder.

[0152] The adhesive layer of Reference Example 2 is an adhesive layer in which copper powder as a conductive filler is mixed into an epoxy resin binder.

[0153] The contact resistivity of the adhesive layer of each of Examples 1 and 2 and Reference Examples 1 and 2 with the superconducting wire was measured. Specifically, the measurement was performed as follows. An adhesive layer 12 was arranged between two strip-shaped superconducting wires in contact with these superconducting wires. A voltage V was applied between the two superconducting wires 1 so that a current flowed from one superconducting wire through the adhesive layer to the other superconducting wire, and the value of the current was measured. From the applied voltage V, the measured value I of the current, and the known contact area A between the superconducting wire and the adhesive layer, the contact resistivity ρ was measured. ct That is, through ρ ct =(V / I)×A, and the contact resistivity ρ is obtained ct .

[0154] Figure 6 The contact resistivity ρ measured as described above is shown for each of the adhesive layers of Examples 1 and 2 and Reference Examples 1 and 2. ct Coordinate diagram of . Figure 6In the figure, a plurality of black circles represent the situation of Example 1, a plurality of white circles represent the situation of Example 2, a plurality of black squares represent the situation of Reference Example 1, and a plurality of white squares represent the situation of Reference Example 2. Figure 6 In FIG. 1 , the horizontal axis shows the content of the conductive filler (in the case of Examples 1 and 2, the conductive filler 12b and the insulating filler 12c are added together) relative to the entire adhesive layer. Figure 6 The vertical axis shows the measured value of contact resistivity (mΩcm 2 ).

[0155] In the case of Reference Example 1, the contact resistivity is 100 mΩcm 2 However, no reliable method has been developed to make it 100 mΩcm. 2 That is, even if the content of the conductive filler 12b (graphite powder) is changed, the contact resistivity does not change much. Moreover, the contact resistivity value has a relatively large deviation.

[0156] In the case of Reference Example 2, the contact resistivity is 10 -1 mΩcm 2 The contact resistivity is not changed much even when the content of the conductive filler 12b (copper powder) is changed.

[0157] On the other hand, in the present embodiment 1, even if the thickness of the adhesive material layer 12 is reduced compared with the cases of reference examples 1 and 2, the contact resistivity is significantly improved by further adding the insulating filler 12c to the adhesive material layer 12. That is, when the thickness of the adhesive material layer 12 is reduced, in reference examples 1 and 2, even if the content of the conductive filler 12b is reduced, the contact resistivity cannot be substantially increased, but in embodiments 1 and 2, the contact resistivity is increased by further adding the insulating filler 12c.

[0158] Thus, even when the thickness of the adhesive material layer 12 is reduced, by further adding the insulating filler 12c, the Figure 6 As shown, the contact resistivity of the adhesive layer 12 can be made significantly larger than that of the case where the insulating filler 12c is not used. For example, in the case of Example 1, the contact resistivity can be reliably made 100 mΩcm without being too small. 2 Above or 1000mΩcm 2 above.

[0159] (Example 3: Case where there are two types of conductive fillers)

[0160] In Example 3, an adhesive layer 12 including two types of conductive fillers 12b1 and 12b2 having different conductivities was formed, and the contact resistivity of the adhesive layer 12 with respect to the superconducting wire 1 was measured while changing the ratio of the two types of conductive fillers 12b1 and 12b2.

[0161] Example 3 is equivalent to the case of the above-mentioned configuration example 2.

[0162] The adhesive material layer 12 of Example 3 is an adhesive material layer formed by mixing graphite powder and copper powder as two conductive fillers 12b1 and 12b2 and magnesium oxide MgO powder as insulating filler 12c in epoxy resin binder 12a. In Example 3, the content of MgO relative to the entire adhesive material layer 12 is 10wt%, and the content of the conductive filler (the total of the two conductive fillers 12b1 and 12b2) relative to the entire adhesive material layer 12 is 30wt%.

[0163] In Example 3, the content of MgO relative to the entire adhesive material layer 12 was fixed at 10 wt %, the content of the conductive filler (the sum of the two conductive fillers 12b1 and 12b2) relative to the entire adhesive material layer 12 was fixed at 30 wt %, the mass ratio of the two conductive fillers 12b1 and 12b2 was changed, and the adhesive material layers 12 were formed at various mass ratios, and the contact resistivity of each adhesive material layer 12 formed in this way was measured. The contact resistivity was measured in the same way as in Examples 1 and 2.

[0164] Fig. 7A The contact resistivity ρ measured in this way is shown in FIG. ct Coordinate diagram of . Fig. 7A In FIG. 1 , the plots of the plurality of triangle marks indicate the measured values ​​of the contact resistivity of each adhesive material layer 12. Fig. 7A In FIG. 1 , the horizontal axis shows the mass ratio of the copper powder to the total mass of the graphite powder and the copper powder as the two conductive fillers 12b1 and 12b2. Fig. 7A In the horizontal axis, 0% indicates a case where copper powder does not exist in the adhesive layer 12 (when the content of graphite is 30%), and 100% indicates a case where graphite powder does not exist in the adhesive layer 12 (when the content of copper is 30%).

[0165] exist Fig. 7A In the process, by gradually reducing the mass ratio of copper powder to graphite powder, the contact resistivity is gradually increased. Fig. 7AAs shown, by adjusting the mixing ratio (mass ratio) of the conductive fillers 12b1 and 12b2 (graphite powder and copper powder) of different conductivity, the conductivity of the adhesive material layer 12 can be adjusted to a desired value or a desired range. In this embodiment, copper powder and graphite powder are selected as the conductive fillers 12b1 and 12b2, but they are not limited to these materials. In addition, powders of three or more materials can also be used. Thus, the contact resistivity within the range obtained in this embodiment can also be obtained.

[0166] Figure 7B Show Fig. 7A The data shown are the current-voltage characteristics of one sample (adhesive material layer 12 in which the mass ratio of copper powder in the entire conductive filler is 5%) in Example 3. Figure 7B In FIG. 1 , the horizontal axis represents the current flowing through the adhesive layer 12 in the thickness direction of the adhesive layer 12 , and the vertical axis represents the voltage applied to the adhesive layer 12 in the thickness direction.

[0167] like Figure 7B As shown, the voltage is generated linearly with respect to the current, and a simple resistive behavior is obtained. This behavior is an important characteristic from the perspective of protecting the superconducting coil from the influence of the quench and its design. For example, due to the linear current-voltage characteristic of the adhesive layer 12, unlike the following case, an excessive increase in the induced current when a quench occurs is prevented, and there is no need to consider complex current-voltage characteristics in the design of the superconducting coil.

[0168] In a superconducting coil of the well-known No-insulation method, Metal as Insulation method, or an intra-Layer No-Insulation method without an adhesive material layer as in the present embodiment, a current bypass path is formed through an interface where the turn portion directly contacts the turn portion, or the turn portion directly contacts the conductor layer. In such an interface, a film such as copper oxide is formed on the surface of the turn portion and the surface of the conductor layer. This film has a nonlinear current-voltage characteristic regardless of thickness, and when the current rises, the voltage rise is saturated or reduced, or otherwise exhibits hysteresis. If such a characteristic exists in the current bypass path, it will cause an excessive rise in the induced current when a superconducting current is quenched. In addition, it is difficult to consider such a complex current-voltage characteristic in the design of a superconducting coil.

[0169] (Experimental Example 1: Function of Insulating Filler)

[0170] An adhesive material layer was formed in which only powder of magnesium oxide MgO as insulating filler 12c was mixed in the epoxy resin binder 12a, and the contact resistivity of the adhesive material layer with respect to the superconducting wire 1 was measured in the same manner as in Examples 1 and 2 while changing the content of the MgO powder. That is, the contact resistivity was measured in a state where the adhesive material layer was sandwiched between two superconducting wires.

[0171] In this measurement method, whether the two superconducting wires sandwiching the adhesive layer are in direct contact (short circuit) is confirmed based on the measured value of contact resistance. In other words, whether the MgO powder in the adhesive layer functions as the above-mentioned spacer is confirmed.

[0172] In addition, when the adhesive layer is formed as thin as possible, the adhesive layer has a thickness corresponding to the content of the insulating filler 12c. That is, the greater the content of the insulating filler 12c, the greater the possible minimum thickness of the adhesive layer. Therefore, in this experimental example, the thickness of the adhesive layer formed as thin as possible was measured for each content of the MgO powder.

[0173] Figure 8 is a table showing such experimental results. Figure 8 The first column of the table shows the content of the MgO powder. The content shows the mass ratio of MgO to the powder of the entire adhesive layer, which is the sum of the binder 12a and the MgO powder. Figure 8 The second column of the table shows whether or not there is a short circuit between the two superconducting wires 1 sandwiching the above-mentioned adhesive layer 12 (that is, whether or not the MgO powder functions as a separator). Figure 8 The third column of the table shows the thickness of the adhesive layer when it is formed as thin as possible as described above.

[0174] exist Figure 8 In the results, no short circuit occurred when the content of the insulating filler 12c was 5wt% or more. Figure 8 As a result, when the content of the insulating filler 12 c was less than 30 wt %, the thickness of the adhesive layer 12 was reduced to 30 μm or less.

[0175] According to such results, in the adhesive material layer 12 of the present embodiment, in order to avoid short circuit between the superconducting wire 1 and the conductor part 13, the mass ratio of the insulating filler 12c to the material including the adhesive 12a and the insulating filler 12c is, for example, 3wt% or more, 4wt% or more, or 5wt% or more. In addition, in the adhesive material layer 12 of the present embodiment, in order to reduce the thickness of the adhesive material layer 12, the mass ratio of the filler including the conductive filler 12b and the insulating filler 12c to the entire adhesive material layer 12 can be, for example, less than 30wt%, less than 25wt%, or less than 20wt%.

[0176] (Experimental Example 2)

[0177] The superconducting coil device 10 of the configuration example 2 of the above-mentioned embodiment was actually manufactured, and the superconducting coil 11 was placed in liquid nitrogen to be in a superconducting state. In this state, the contact resistivity of the current bypass path with respect to the turn portion T of the superconducting coil 11 was measured, and the critical current value of the superconducting coil 11 was measured. Then, the superconducting coil 11 was taken out of the liquid nitrogen to be in a normal conductive state, and was placed in the liquid nitrogen again to be in a superconducting state. In this state, the contact resistivity was measured in the same manner, and the critical current value of the superconducting coil 11 was measured. Such a cooling cycle was repeated.

[0178] Fig. 9A and Fig. 9B The graphs are respectively showing the contact resistivity and critical current value measured in each of these cycles. Fig. 9A As shown in FIG. 1 , even if the cooling cycle is repeated, the contact resistivity (shunt resistance) does not change significantly and remains at a roughly stable value. Fig. 9B As shown, even if the cooling cycle is repeated, the critical current value is stably maintained at a constant value. Thus, in the superconducting coil 11 of the present embodiment, it was confirmed that the contact resistivity and the critical current value are stably maintained at a constant value even if the cooling cycle is repeated.

[0179] [Second embodiment]

[0180] Hereinafter, a superconducting coil device 10 according to a second embodiment of the present invention will be described. In the second embodiment, matters not described below may be the same as those in the first embodiment. For example, as described above, the superconducting coil 11 may be a solenoid coil (cylindrical coil), but may also have other shapes such as a racetrack shape or a D-shaped shape.

[0181] <Structure of superconducting coil device>

[0182] Fig. 10A and Fig. 10B They are Figure 1The enlarged view of the regions R2 and R3 surrounded by the dotted lines in FIG. 1 shows the situation of the second embodiment. On the other hand, Fig.11A and Fig. 11B They are also Figure 1 1 is an enlarged view of the regions R2 and R3 surrounded by dotted lines in FIG. 1 , but shows the situation of the above-mentioned first embodiment.

[0183] Hereinafter, the inner coil layer and the outer coil layer refer to a specific pair of coil layers adjacent to each other in the radial direction. However, the following contents related to the inner coil layer and the outer coil layer also apply to any pair of coil layers adjacent to each other.

[0184] The inner coil layer is Fig. 10A and Fig.11A The second coil layer from the inside in the radial direction is Fig. 10B and Fig. 11B The first coil layer is from the inner side in the radial direction. Figures 10A to 11B As shown in each example, the superconducting wire 1 is provided with a Fig. 10A The middle is the lower end, Fig. 10B The inner coil layer is formed by transferring axially and extending around the center axis C to the other end of the axial direction, and then transferring radially outwardly of the inner coil layer to form an outer coil layer by transferring axially from the other end of the axial direction to one end of the axial direction while extending around the center axis C.

[0185] exist Figures 10A to 11B , Te shows a plurality of (two in the examples of these figures) turn portions T located at the other axial end in the inner coil layer. Ts shows a plurality of (two in the examples of these figures) turn portions T located at the other axial end in the outer coil layer.

[0186] In the first embodiment described above, Fig.11A and Fig. 11B As shown, there is no interlayer current bypass path from the turn portion Te located at the other axial end in the inner coil layer to the turn portion Ts located at the other axial end in the outer coil layer. In this case, if a quench occurs near the portion of the superconducting wire 1 that is transferred from the inner coil layer to the outer coil layer, the superconducting wire 1 may be burned.

[0187] Taking this into consideration, in the second embodiment, Fig. 10A and Fig. 10B As shown, the structure is composed of one or more coils located at the other axial end of the inner coil layer (in Fig. 10A and Fig. 10B 2) turn portion Te and one or more (in Fig. 10A and Fig. 10B(in the figure, there is an interlayer current bypass path in which two turn parts Ts are electrically connected.)

[0188] The interlayer current bypass path is composed of a portion of the adhesive material layer 12, a portion of the conductor portion 13, and the interlayer conductor portion 16. The portion of the adhesive material layer 12 and the portion of the conductor portion 13 are portions sandwiched in the radial direction by the other axial end of the inner coil layer and the other axial end of the outer coil layer. The interlayer conductor portion 16 electrically connects the portion of the conductor portion 13 to the other axial end of the outer coil layer.

[0189] More specifically, the interlayer conductor portion 16 contacts the portion of the conductor portion 13 from the radially outer side, and contacts one or more interlayer conductor portions (in the radially inner side and the outer side) located at the other axial end of the coil layer. Fig. 10A and Fig. 10B The interlayer conductor portion 16 may be formed in a sheet shape having a thin thickness in the radial direction. In addition, the interlayer conductor portion 16 may extend in the circumferential direction and the axial direction along the conductor portion 13 and one or more turn portions Ts in contact in the radial direction. For example, the interlayer conductor portion 16 may be formed in a shape (e.g., cylindrical) that goes around in the circumferential direction. In addition, the interlayer conductor portion 16 may also be formed integrally with the conductor portion 13.

[0190] For example, Fig. 10A and Fig. 10B As shown by the dotted arrow, the above-mentioned interlayer current bypass path is, for example, a path from the turn portion Te at the other axial end of the inner coil layer in the radial direction through the adhesive material layer 12, the conductor portion 13 and the interlayer conductor portion 16 to the turn portion Ts at the other axial end of the outer coil layer.

[0191] Thus, the superconducting coil device 10 of the second embodiment includes the above-mentioned interlayer conductor portion 16. The interlayer conductor portion 16 is provided in place of the portion of the interlayer insulating portion 14 sandwiched in the radial direction by the above-mentioned other axial end portion of the inner coil layer and the above-mentioned other axial end portion of the outer coil layer in the first embodiment. That is, in the second embodiment, the portion of the interlayer insulating portion 14 is omitted, and the interlayer conductor portion 16 is provided in the region of the omitted portion.

[0192] <Effects of the Second Embodiment>

[0193] In addition to the effects (1) to (6) of the first embodiment, the following effects can be obtained. In the superconducting coil 11, the interlayer current bypass path is also formed for the turn portions Te and Ts of the portion (the other axial end portion) where the superconducting wire 1 is folded back between the inner coil layer and the outer coil layer. Therefore, the other axial end portion in the inner coil layer can also be prevented from burning due to the occurrence of quench.

[0194] [Third embodiment]

[0195] Hereinafter, a superconducting coil device 10 according to a third embodiment of the present invention will be described. In the third embodiment, matters not described below may be the same as those in the first embodiment.

[0196] <Structure of superconducting coil device>

[0197] Fig.12 1 is a perspective view showing a cross section of a superconducting coil device 10 according to a third embodiment of the present invention. The cross section is a cross section taken along a virtual plane including the central axis C of the superconducting coil 11. In addition, except for the cases mentioned below, a cross section of the superconducting coil device 10 taken along any virtual plane including the central axis C may be the same as the cross section of the superconducting coil device 10. Fig.12 In addition, the superconducting coil 11 may be Fig.12 The configuration example is a solenoid coil (cylindrical coil), but may have other shapes such as a racetrack shape or a D shape.

[0198] Fig.13 yes Fig.12 An enlarged view of the area R4 surrounded by the dotted line in FIG. Fig.14A and Fig. 14B Both Fig.12 , but shows different configuration examples. Fig.14A and Fig. 14B In FIG. 1 , the arrows indicated by the dotted lines indicate the order in which the current passes through the plurality of turn portions T while flowing in the circumferential direction.

[0199] <Structure of superconducting coil>

[0200] In the third embodiment, the superconducting coil 11 formed by winding the superconducting wire 1 into a coil is a so-called pancake-shaped coil. Figure 12 to Figure 14BAs shown, the superconducting wire 1 is wound around the central axis C multiple times (for example, many times) while maintaining a constant axial position parallel to the central axis C of the superconducting coil 11. That is, the superconducting wire 1 extends from the innermost position in the radial direction to the outermost position in the radial direction in a manner that shifts outward in the radial direction as it winds around the central axis C while maintaining a constant axial position. Here, the superconducting wire 1 can be a continuous superconducting wire, or it can be formed by connecting a plurality of superconducting wires in series. In the latter case, the superconducting wire 1 can have a plurality of superconducting wires connected in series, and a connection portion between these superconducting wires. The connection portion can be formed by welding, heat treatment, etc.

[0201] In the third embodiment, Figure 12 to Figure 14B As shown, a superconducting wire 1 extending from a radially inner end to a radially outer end while surrounding a central axis C while maintaining a constant axial position is defined as one coil layer in the axial direction (hereinafter also referred to as a coil layer).

[0202] According to the third embodiment, the superconducting coil 11 may be composed of one coil layer or may be composed of two layers. Fig.12 Thus, it is composed of a plurality of (for example, a large number of) coil layers stacked in the axial direction.

[0203] For example, a plurality of coil layers can be formed from superconducting wire 1 as shown below.

[0204] For each pair of coil layers that are continuous with each other on the inner side in the radial direction and adjacent to each other in the axial direction, in one example, Fig.13 , Fig.14A or Fig. 14B As shown, the superconducting wire 1 forms an inner interlayer turn portion Ta (see FIG. 1 ) by continuously extending in the circumferential direction from the position of the turn portion T constituting the innermost side (left side of these figures) in one coil layer (circumferential position different from the cross-section shown in these figures) while shifting radially inward and axially shifting toward the other coil layer side. Fig.13 , Fig.14A or Fig. 14B ), then, by continuously extending outward in the circumferential direction while shifting in the axial direction toward the other coil layer side, the innermost turn portion T (with the same Fig.13 Here, as described above, the superconducting wire 1 may be a single continuous superconducting wire, or may be a plurality of superconducting wires connected in series (the same applies hereinafter).

[0205] For each pair of coil layers that are continuous with each other on the outside in the radial direction and adjacent in the axial direction, as shown in FIG. Fig.14AAs shown, in the transition portion between the coil layers, the end of the superconducting wire 1 forming one coil layer and the end of the superconducting wire 1 forming the other coil layer can be connected to each other via a connection portion 18 formed by welding, heat treatment, etc.

[0206] In another example, for each pair of coil layers that are continuous with each other on the outside in the radial direction and adjacent in the axial direction, as shown in FIG. Fig. 14B As shown in the figure, the superconducting wire 1 is further extended in the circumferential direction from the position of the superconducting wire 1 constituting the outermost turn portion T in one coil layer (the circumferential position different from the cross-section shown in these figures) while shifting radially outward and shifting axially toward the other coil layer side to form the outer interlayer turn portion Tb (refer to Fig. 14B ), and then, by continuously extending circumferentially inwardly while shifting axially toward the other coil layer side, the outermost turn portion T in the other coil layer is formed.

[0207] In addition, if Fig. 14B As shown, the inner interlayer turn portions Ta and the outer interlayer turn portions Tb may be alternately arranged in the axial direction.

[0208] <Configuration related to current bypass path>

[0209] The superconducting coil device 10 of the third embodiment includes a conductive adhesive material layer 12 in contact with a plurality of (for example, all) turn portions T of the superconducting coil 11 in one coil layer. The adhesive material layer 12 constitutes a current bypass path that electrically connects the plurality of turn portions T in one coil layer. The configuration of the adhesive material layer 12 may be the same as that of the adhesive material layer 12 of the first embodiment (for example, the adhesive material layer 12 of the above-mentioned configuration example 1 or configuration example 2).

[0210] A superconducting coil device 10 according to the third embodiment includes an adhesive layer 12 and a conductor portion 13 provided corresponding to each coil layer.

[0211] Regarding each coil layer, the adhesive material layer 12 and the conductor portion 13 are Figure 13 to Figure 14B In the example, the two sides are arranged on one axial side and the other axial side of the coil layer. The structure consisting of such a coil layer, and the adhesive material layer 12 and the conductor part 13 arranged on each axial side of the coil layer can be stacked in the axial direction via the interlayer insulating part 14. The adhesive material layer 12 and the conductor part 13 arranged on one axial side of the coil layer are described below, but the various matters (structure, configuration, function, etc.) of the adhesive material layer 12 and the conductor part 13 arranged on the other axial side of the coil layer are also the same as the various matters of the adhesive material layer 12 and the conductor part 13 arranged on the one axial side.

[0212] In the third embodiment, the adhesive material layer 12 and the conductor part 13 are provided corresponding to each coil layer. The adhesive material layer 12 and the conductor part 13 can be formed into a layer or sheet with a thin thickness in the axial direction. Such an adhesive material layer 12 and the conductor part 13 can extend in the circumferential direction and the radial direction along the coil layer adjacent to the adhesive material layer 12 and the conductor part 13 in the axial direction. Such an adhesive material layer 12 and the conductor part 13 can each extend continuously in the circumferential direction and the radial direction over the entire corresponding coil layer.

[0213] Furthermore, the adhesive material layer 12 corresponding to each coil layer also has a function of bonding the superconducting wire 1 repeatedly wound around the central axis C and the conductor portion 13 in the coil layer.

[0214] The adhesive layer 12 corresponding to each coil layer forms a current bypass path that electrically connects the turns of the superconducting coil 11 in the coil layer together with the conductor portion 13 corresponding to the coil. In this way, a current bypass path is formed for each coil layer.

[0215] The current bypass path formed by the adhesive material layer 12 and the conductor portion 13 is, for example, the following path: Fig.13 As shown by the dotted arrow, in the corresponding coil layer, from any turn portion T, the conductor portion 13 is reached via the adhesive material layer 12, and the conductor portion 13 is advanced in the radial direction to reach another (for example, adjacent) turn portion T from the conductor portion 13 via the adhesive material layer 12.

[0216] The interlayer insulating portion 14 is provided between each pair of coil layers adjacent to each other in the axial direction, and electrically insulates the coil layers from each other. For each pair of coil layers, the interlayer insulating portion 14 is provided between one coil layer or its current bypass path (i.e., the conductor portion 13) and the other coil layer of the pair or its current bypass path. In this configuration, the interlayer insulating portion 14 prevents the conductor portion 13 corresponding to each coil layer from contacting the coil layer (superconducting wire 1) adjacent to the coil layer.

[0217] In addition, the other structures of the conductor portion 13 and the interlayer insulating portion 14 may be the same as the structures of the conductor portion 13 and the interlayer insulating portion 14 of the first embodiment, respectively.

[0218] <Configuration related to insulation between adjacent turns>

[0219] like Fig.13 As shown, the superconducting coil device 10 includes an inter-turn insulating portion 15 provided between each pair of radially adjacent turn portions T in each coil layer to prevent radial contact between the turn portions T. The inter-turn insulating portion 15 is formed of a material having electrical insulation properties.

[0220] The inter-turn insulating portion 15 has a linear (e.g., strip-shaped) shape extending along the superconducting wire 1 around the central axis C. That is, the inter-turn insulating portion 15 may have a shape wound around the central axis C while shifting along the superconducting wire 1 in the radial direction of the superconducting coil 11. More specifically, the inter-turn insulating portion 15 may extend along the superconducting wire 1 around the central axis C in the entire long side direction of the superconducting wire 1 (the entire direction in which the superconducting wire 1 extends around the central axis C) while contacting the superconducting wire 1 in the radial direction.

[0221] <Interlayer current bypass path>

[0222] like Figure 13 to Figure 14B As shown, for each pair of coil layers that are continuous with each other on the inner side in the radial direction and adjacent in the axial direction, an interlayer current bypass path can be formed to electrically connect the radially innermost turn portion T in one coil layer with the radially innermost turn portion T in the other coil layer.

[0223] Such an interlayer current bypass path is formed by the interlayer conductor portion 16. For each pair of coil layers, the interlayer conductor portion 16 can extend in the axial direction and the circumferential direction in a manner of contacting both the radially innermost turn portion T in one coil layer and the radially innermost turn portion T in the other coil layer. In this regard, the radially innermost turn portion T in one coil layer and the radially innermost turn portion T in the other coil layer can also be connected via an adhesive material layer (not shown) having the same structure as the adhesive material layer 12. The thickness direction of the adhesive material layer is the radial direction of the superconducting coil 11.

[0224] Likewise, if Fig. 14B As shown, for each pair of coil layers that are continuous with each other on the outside in the radial direction and adjacent in the axial direction, an interlayer current bypass path can also be formed to electrically connect the radially outermost turn portion T in one coil layer with the radially outermost turn portion T in the other coil layer.

[0225] Such an interlayer current bypass path is formed by the interlayer conductor portion 16. For each pair of coil layers, the interlayer conductor portion 16 can extend in the axial direction and the circumferential direction in a manner of contacting both the radially outermost turn portion T in one coil layer and the radially outermost turn portion T in the other coil layer. In this regard, the radially outermost turn portion T in one coil layer and the radially outermost turn portion T in the other coil layer can also be connected via an adhesive material layer (not shown) having the same structure as the adhesive material layer 12. The thickness direction of the adhesive material layer is the radial direction of the superconducting coil 11.

[0226] In addition, for each pair of coil layers mentioned above, if Fig.13 , Fig.14A or Fig. 14BAs shown, the interlayer conductor portion 16 can be configured to contact the radial inner end surface or the radial outer end surface of the adhesive material layer 12 and the conductor portion 13 corresponding to one coil layer, and the radial inner end surface or the radial outer end surface of the adhesive material layer 12 and the conductor portion 13 corresponding to the other coil layer.

[0227] In addition, for each pair of coil layers, the interlayer conductor portion 16 may be provided so as to be aligned with the interlayer turn portion (in Fig.13 The middle is the interlayer turn part Ta, Fig. 14B In this regard, the interlayer conductor portion 16 may also be connected to the interlayer turn portions Ta and Tb located between the coil layers via an adhesive material layer (not shown) having the same structure as the adhesive material layer 12. The thickness direction of the adhesive material layer is the radial direction of the superconducting coil 11.

[0228] <Another configuration example>

[0229] Fig.15 yes Fig.12 The enlarged view of the region R4 surrounded by the dotted line in FIG. 1 shows another configuration example of the third embodiment. Fig.15 In the configuration example, for each coil layer, the adhesive material layer 12 and the conductor portion 13 are provided only on one side of the axial direction and the other side of the coil layer. Fig.15 The other matters can be Fig.13 , Fig.14A or Fig. 14B The configuration examples are the same as those of , and therefore, their descriptions are omitted.

[0230] <Another configuration example>

[0231] Fig.16 yes Fig.12 The enlarged view of the region R4 surrounded by the dotted line in FIG. 1 shows another configuration example of the third embodiment. Fig.16 In the configuration example, a double pancake-shaped coil is formed by a pair of coil layers adjacent to each other in the axial direction.

[0232] A pair of coil layers constituting the double pancake-shaped coil are electrically insulated from each other by providing an interlayer insulating portion 17 between them in the axial direction.

[0233] In addition, regarding a pair of coil layers constituting the double pancake-shaped coil, the adhesive material layer 12 and the conductor portion 13 of each coil layer are provided on the side opposite to the other coil layer.

[0234] For a pair of coil layers constituting a double pancake-shaped coil, an inner or outer interlayer turn portion (in the Fig.16The inner interlayer turn portion Ta is provided with an interlayer conductor portion 16 similar to the above.

[0235] Such a double pancake-shaped coil and the adhesive material layer 12 and the conductor portion 13 on each axial side of the coil can be stacked in the axial direction via the interlayer insulating portion 14. A plurality of double pancake-shaped coils stacked in this way can be composed of the superconducting wire 1 in such a manner that the inner or outer interlayer turn portions Ta and Tb described above are formed between adjacent double pancake-shaped coils.

[0236] for Fig.16 The other matters can be Fig.13 , Fig.14A or Fig. 14B The configuration examples are the same as those of , and therefore, their descriptions are omitted.

[0237] <Another configuration example>

[0238] Fig.17 yes Fig.12 The enlarged view of the region R4 surrounded by the dotted line in FIG. 1 shows another configuration example of the third embodiment. Fig.17 In the configuration example, in each coil layer, an adhesive material layer 12 is provided instead of the above-mentioned inter-turn insulating portion 15. Fig.17 In the configuration example, in each coil layer, an adhesive material layer 12 is provided between each pair of turn portions T adjacent in the radial direction. Thus, in each coil layer, the adhesive material layer 12 constitutes a current bypass path that electrically connects each pair of turn portions T adjacent in the radial direction.

[0239] The current bypass path formed by the adhesive material layer 12 is as follows Fig.17 The dashed arrow in FIG. 1 shows a path for bypass current to flow from any turn portion T to the adjacent turn portion T via the adhesive material layer 12 in the radial direction. Fig.17 As shown, in each coil layer, each pair of turn portions T of the adhesive material layer 12 adjacent to each other in the radial direction may be in contact with the two turn portions T.

[0240] The adhesive material layer 12 has a central axis C (see Fig.12 That is, in each coil layer, the adhesive material layer 12 can extend around the central axis C while shifting in the radial direction of the superconducting coil 11 from the radially inner end of the superconducting wire 1 to the radially outer end along the superconducting wire 1.

[0241] In addition, Fig.17 In the example of the composition of Fig.13Similarly to the configuration example of , the interlayer insulating portion 14 is provided between each pair of coil layers adjacent to each other in the axial direction, and the coil layers are electrically insulated from each other. Fig.17 In the example of the composition, it can be Fig.13 Unlike the configuration example, no adhesive layer 12 is provided between coil layers adjacent to each other in the axial direction. Fig.17 In the example of the composition, it can be Fig.13 , Fig. 14B The structure example is different from that of FIG. 1 , in which the conductor portion 13 and the interlayer conductor portion 16 are omitted. Fig.17 In the example of the composition, other matters can be Fig.13 , Fig.14A or Fig. 14B The configuration examples are the same as those of , and therefore, their descriptions are omitted.

[0242] <Effects of the Third Embodiment>

[0243] In the third embodiment, the effects (1) and (2) described above in the first embodiment can also be obtained. In the third embodiment, the same effects as the effects (3) to (6) described above in the first embodiment can also be obtained as follows.

[0244] like Figure 13 to Figure 16 As shown, the conductor 13 extends in the radial direction adjacent to the plurality of turn portions T arranged in the radial direction and is electrically connected to the plurality of turn portions T via the adhesive layer 12. Thus, a current bypass path having the above-mentioned effects (1) and (2) can be formed.

[0245] Or, if Fig.17 As shown, each pair of turn portions T adjacent to each other in the radial direction is electrically connected to each other via the adhesive layer 12 sandwiched between the two turn portions T. Thus, a current bypass path having the above-mentioned effects (1) and (2) can be formed.

[0246] In addition, if Figure 13 to Figure 16 As shown, the inter-turn insulating portion 15 is provided between each pair of turn portions T adjacent to each other in the radial direction, so as to prevent the turn portions T from contacting each other in the axial direction.

[0247] In addition, if Figure 13 to Figure 16 As shown, for each coil layer, the adhesive material layer 12 extends in the radial direction and the circumferential direction in a manner that contacts the axial end faces of the plurality of (all) turn portions T of the superconducting wire 1 forming the coil layer, and the conductor portion 13 extends in the radial direction and the circumferential direction in a manner that contacts the axial end face (the entire axial end face) of the adhesive material layer 12. Therefore, by heat transfer from the superconducting wire 1 to the conductor portion 13 via the adhesive material layer 12, the cooling of the superconducting wire 1 can be promoted.

[0248] The adhesive material layer 12 mechanically bonds a plurality of (all) turns of the superconducting wire 1 in each coil layer to form an integrated whole.

[0249] The present invention is not limited to the above-mentioned embodiments, and various changes can be made within the scope of the technical concept of the present invention. For example, the superconducting coil device of the embodiment of the present invention may not have all of the above-mentioned multiple items, or may have only a part of the above-mentioned multiple items. In addition, within the scope that at least a part of the above-mentioned problems can be solved, or within the scope that at least a part of the effects described in this specification can be obtained, one or more components described in the claims and this specification can be omitted, or any combination of multiple components described in the claims and this specification can be made.

[0250] In addition, any one of the following modifications 1 to 7 may be adopted, and two or more of the modifications 1 to 7 may be arbitrarily combined and adopted within the range that no contradiction occurs. In this case, matters not described below may be the same as those described above, or may be appropriately changed.

[0251] (Change Example 1)

[0252] A bundled superconducting wire 1A may be used instead of the above-mentioned superconducting wire 1. That is, in each of the above-mentioned first to third embodiments, a bundled superconducting wire 1A in which a plurality of superconducting wires 1 are bundled may be used instead of the above-mentioned superconducting wire 1.

[0253] Fig.18A and Fig.18B FIG. 1 is a cross-sectional configuration example of such a bundle-type superconducting wire 1A. In this modification example 1, a plurality of (in Fig.18A and Fig.18B The superconducting wires 1 are bonded to each other via the adhesive layer 12, so that the adhesive layer 12 forms a current bypass path between the plurality of superconducting wires 1. The adhesive layer 12 also has the function of bonding the plurality of superconducting wires 1 together through its adhesive 12a. Fig.18A and Fig.18B In the embodiment, the relative positions of the superconducting layers 2a in the two superconducting wires 1 constituting the bundle-type superconducting wire 1A are different from each other.

[0254] When the bundle-type superconducting wire 1A is used, in the first to third embodiments described above, the superconducting wire 1 described above can be interpreted as the bundle-type superconducting wire 1A.

[0255] Conventional bundled superconducting wires are made by directly bonding two superconducting wires, so the contact resistance between the two superconducting wires is small and unstable, and varies depending on the position. As a result, there is a possibility that bias current will occur when the superconducting coil is excited, and overcurrent will flow when the superconducting coil is quenched.

[0256] In contrast, in the present modification example 1, the plurality of superconducting wires 1 constituting the bundled superconducting wire 1A are bonded via the adhesive material layer 12, so that the contact resistivity of the plurality of superconducting wires 1 via the adhesive material layer 12 (current bypass path) is prevented from becoming too low, and the value thereof can be adjusted to a desired value or range. Thus, the above-mentioned bias current and overcurrent can be suppressed.

[0257] (Change Example 2)

[0258] According to the second modification, when the superconducting coil 11 is formed by the bundled superconducting wire 1A of the first modification, the current bypass path (adhesive layer 12 and conductor portion 13) connecting the plurality of turn portions to each other and the interlayer current bypass path (interlayer conductor portion 16) can be omitted.

[0259] Fig.19A yes Figure 1 The enlarged view of the region R1 surrounded by the dotted line shows the configuration example of this modification example 2. Fig.19A As shown in the figure, the structure in which the bundle-type superconducting wire 1A is wound around the central axis C while being transferred in the axial direction is used as one coil layer in the radial direction, and the superconducting coil 11 can have a plurality of coil layers adjacent to each other in the radial direction, or one coil layer. In each coil layer, an inter-turn insulating portion 15 is provided between each pair of turn portions T adjacent to each other in the axial direction. In addition, an interlayer insulating portion 14 is provided between each pair of coil layers adjacent to each other in the radial direction.

[0260] Fig.19B yes Fig.12 This is an enlarged view of the region R4 surrounded by the dotted line, but shows the configuration example of this modification example 2. Fig.19B As shown in the figure, the bundle-type superconducting wire 1A is extended from the inner end in the radial direction while surrounding the central axis C to the outer end in the radial direction as one coil layer in the axial direction, and the superconducting coil 11 may have a plurality of coil layers adjacent to each other in the axial direction, or one coil layer. In each coil layer, an inter-turn insulating portion 15 is provided between each pair of turn portions T adjacent to each other in the radial direction. In addition, an interlayer insulating portion 14 is provided between each pair of coil layers adjacent to each other in the axial direction.

[0261] (Change Example 3)

[0262] In the above, the superconducting wire 1 is composed of the superconducting layer 1a which is a high-temperature superconductor, but it can also be composed to include the superconducting layer 1a which is a so-called low-temperature superconductor. In this case, the superconducting wire 1 can be, for example, a superconducting wire formed by covering the superconducting layer 1a which is a low-temperature superconductor with a stabilizing layer formed by a material (such as copper or stainless steel) that stabilizes the superconducting state. The low-temperature superconductor can be a low-temperature superconductor having a transition temperature of more than the boiling point (4.2K) of liquid helium and less than 25K.

[0263] (Change Example 4)

[0264] according to Fig. 7A According to the data of Example 3, in any implementation related to the superconducting coil 11, different contact resistivity values ​​or ranges thereof can be selected according to the parts of the superconducting coil 11 to produce the superconducting coil 11. Therefore, compared with the case where a single contact resistivity value is set for all parts, the excessive temperature rise and excessive induction conduction rise (the mechanical damage caused by the quench) caused by the quench can be effectively avoided. For example, in the superconducting coil 11, the contact resistivity of the part that is easy to become the starting point of the quench can be set lower than that of other parts, and the contact resistivity of the part where the induced current is easy to rise due to the magnetic coupling between the turn parts T can be set higher than that of other parts. In this way, the temperature rise at the starting point of the quench can be suppressed, and the local induction conduction rise can be suppressed. The level of the induced current not only tends to increase due to the influence of magnetic coupling, but also tends to increase in parts with low empirical magnetic fields and high superconducting critical currents. It is also effective to select a higher contact resistivity value in such a part. The selection of the contact resistivity value can be obtained by circuit analysis and thermal conduction analysis based on the specifications of the specific superconducting coil.

[0265] (Change Example 5)

[0266] Fig. 20A yes Figure 5A , but shows the situation of this modification example 5. That is, Fig. 20A The configuration example in which the adhesive material layer 12 of this modification example 5 is applied to the adhesive material layer 12 of the first embodiment is shown. However, the adhesive material layer 12 of this modification example 5 may also be applied to the adhesive material layer 12 in the second embodiment, the third embodiment, modification example 1, or modification example 2. That is, the following reference Fig. 20A or the following Fig. 20B and Fig. 20C The adhesive material layer 12 of the modified example 5 described above may be the adhesive material layer 12 of any one of the first embodiment, the second embodiment, the third embodiment, the modified example 1, and the modified example 2. In the modified example 5, one or both of the modified examples 3 and 4 described above may be adopted.

[0267] The adhesive material layer 12 of this modification example 5 is as follows Fig. 20A In the present modification example 5, the adhesive material layer 12 has an adhesive 12a and a fibrous body 12d. The adhesive material layer 12 can be formed by, for example, impregnating or applying the adhesive 12a (for example, by vacuum pressure impregnation) to the fibrous body 12d. Alternatively, the adhesive 12a can be applied to the bonding object (in the Fig. 20A In the example of the superconducting wire 1 and the conductor part 13) and the fiber body 12d, one or both of them are sandwiched between these bonding objects in a manner that these bonding objects are pressed against the fiber body 12. In this way, the bonding material layer 12 can be formed.

[0268] The fiber body 12d is formed of conductive fibers 12d1. The fiber body 12d may be a fiber fabric woven from the fibers 12d1, or a fiber braided from the fibers 12d1. The fiber body 12d may be, for example, a fiber body formed in a sheet shape. In this case, the thickness direction of the sheet-shaped fiber body 12d may be the same as the thickness direction of the adhesive material layer 12. In one example, the fiber body 12d may be a conductive mesh (e.g., a metal mesh) formed of conductive fibers 12d1.

[0269] The fiber body 12d imparts conductivity to the adhesive material layer 12 by having conductivity. On the other hand, since the fiber body 12d is formed of the fibers 12d1, the entire contact surface of the adhesive material layer 12 with the superconducting wire 1 does not become a conductive portion (fiber body 12d), and the proportion of conductivity in the contact surface can be suppressed by the density of the fibers 12d (for example, the opening ratio of the metal mesh as the fiber body 12d). In this way, the fiber body 12d constitutes a resistance reduction suppression structure that not only imparts conductivity to the adhesive material layer 12 but also suppresses a reduction in the contact resistance (contact resistivity) between the adhesive material layer 12 and the superconducting wire 1.

[0270] based on Fig. 20B and Fig. 20C Another configuration example of the fiber body 12 in the fifth modification will be described. Fig. 20B This is an enlarged cross-sectional view showing another configuration example of the fiber body 12d in Modification Example 5. Fig. 20C yes Figure 5A The enlarged view of the modification example 5 is shown. Fig. 20B The case of the fiber body 12d.

[0271] In this other configuration example, the fiber body 12d may be pre-rolled or cut before using the adhesive material layer 12. Fig. 20BAs shown, the fiber body 12d has a plurality of local regions 12f ( Fig. 20B The fiber body 12d is rolled or cut in a flat or nearly flat manner to make each local area 12f on the left side of the fiber body 12d. Thus, a substantially flat portion in contact with the superconducting wire 1 is formed by a plurality of planar or nearly planar local areas 12f. These local areas 12f are located along a virtual plane. In addition, by such rolling or cutting, the fiber body 12d is formed on the side opposite to the above ( Fig. 20C ), similarly, many local areas 12f are formed in a substantially planar portion (for example, in contact with the conductor portion 13) in a flat manner or in a manner close to a planar surface.

[0272] Thus, by forming a substantially flat portion in contact with the superconducting wire 1 in the fiber body 12d, the contact area between the fiber body 12d and the superconducting wire 1 can be adjusted. Thus, the contact resistivity (shunt resistance) can be controlled with greater accuracy. Fig. 20C As shown, the contact area between the fiber body 12d and the conductor part 13 can be adjusted.

[0273] According to the fifth modification, by changing the density of the fiber 12d (for example, the opening ratio of the metal mesh as the fiber body 12d), Fig. 20B By adjusting the areas of the substantially planar portions of the plurality of local regions 12f, the contact resistance can be controlled to an arbitrary value. Fig.21 The following table shows the results of measuring the contact resistivity (shunt resistance) between the adhesive layer 12 and the superconducting wire 1 when a metal mesh is used as the fiber body 12d. The measurement was performed on adhesive layers 12 having different metal mesh densities (mesh area ratios). Fig.21 The horizontal axis shows the ratio of the metal portion in the surface of the sheet-like metal mesh (equivalent to the density of the metal mesh). Fig.21 It can be seen that the contact resistivity can be adjusted by changing the density of the metal mesh.

[0274] According to this modification example 5, if Fig. 20A or Fig. 20C As shown, the adhesive layer 12 is formed of the binder 12 a and the fiber body 12 d . Therefore, the current bypass path of the superconducting coil 11 can be formed relatively easily by the adhesive layer 12 .

[0275] In the fifth modification, as in the first embodiment, the thickness of the adhesive layer 12 can be reduced. For example, the thickness of the adhesive layer 12 can be reduced to 30 μm or less.

[0276] According to the fifth modification, the fiber body 12d can be formed of the regularly arranged fibers 12d1. This can stabilize the contact resistivity between the adhesive layer 12 and the superconducting wire 1.

[0277] Fig. 22 Shown with Fig. 9A The measured results of the contact resistivity (shunt resistance) in the case of the present modification example 5 are shown. That is, the adhesive material layer 12 of the present modification example 5 is actually used in the superconducting coil device 10 of the first embodiment. Fig. 9A Similarly, in this modification 5, the contact resistivity (shunt resistance) is also measured for the repetition of the above cooling cycle. Fig. 22 It is found that in the fifth modification, even after the repetition of the cooling cycle, the contact resistivity between the adhesive layer 12 and the superconducting wire 1 is highly stable.

[0278] (Change Example 6)

[0279] In the above-mentioned modification 5, the adhesive material layer 12 includes one or both of the powdered conductive filler 12b and the powdered insulating filler 12c described in the first embodiment, in addition to the above-mentioned binder 12a and fibrous body 12d. Here, as the conductive filler 12b, a plurality of conductive fillers having different conductivities (for example, the above-mentioned first conductive filler 12b1 and the second conductive filler 12b2) may be provided.

[0280] In this way, in the adhesive material layer 12, by using one or both of the powdered conductive filler 12b and the powdered insulating filler 12c in addition to the fiber body 12d (for example, a metal mesh), the value of the contact resistance (contact resistivity) between the adhesive material layer 12 and the superconducting wire 1 can be controlled with higher precision.

[0281] (Change Example 7)

[0282] In the first embodiment, Fig.17 Similarly, in each coil layer, an adhesive material layer 12 may be provided instead of the inter-turn insulating portion 15. That is, in this modification 7, in each coil layer, an adhesive material layer 12 in contact with the two turn portions T is provided between each pair of turn portions T adjacent in the axial direction. Thus, in each coil layer, the adhesive material layer 12 constitutes a current bypass path that electrically connects each pair of turn portions T adjacent in the axial direction.

[0283] In addition, the present modification example 7 may be configured as follows. The interlayer insulating portion 14 is provided between each pair of coil layers adjacent to each other in the radial direction, and electrically insulates the coil layers from each other. Figure 3Different from the above, the adhesive material layer 12 may not be provided between the coil layers adjacent to each other in the radial direction. Figure 3 The conductor part 13 may be omitted. Regarding this modification example 7, other matters may be the same as those of the first embodiment.

Claims

1. A superconducting coil device, characterized in that: have: a superconducting coil formed by winding a superconducting wire into a coil; and an adhesive material layer constituting at least a portion of the current bypass path of the superconducting coil, containing an adhesive and imparted with electrical conductivity, The adhesive layer has a resistance reduction suppressing structure that provides conductivity to the adhesive layer and suppresses a reduction in contact resistance between the adhesive layer and the superconducting wire.

2. The superconducting coil device according to claim 1, wherein: The resistance drop suppression structure includes a conductive filler and an insulating filler.

3. The superconducting coil device according to claim 1, wherein: The resistance drop suppression structure includes a fiber body formed of fibers having conductivity.

4. The superconducting coil device according to claim 3, wherein: The resistance drop suppression structure further includes one or both of a powdery conductive filler and a powdery insulating filler.

5. The superconducting coil device according to any one of claims 1 to 4, wherein: The adhesive material layer is in contact with a plurality of turn portions of the superconducting coil at one side in the thickness direction of the adhesive material layer. A conductor portion is provided which is in contact with the adhesive layer on the other side in the thickness direction of the adhesive layer and extends along the adhesive layer, The current bypass path that electrically connects the plurality of turn portions to each other is formed by the adhesive material layer and the conductor portion.

6. The superconducting coil device according to any one of claims 1 to 4, wherein: The superconducting wire is formed by bundling a plurality of superconducting wires. The plurality of superconducting wires are bonded to each other via the adhesive layer, so that the adhesive layer constitutes the current bypass path that electrically connects the plurality of superconducting wires to each other.

7. The superconducting coil device according to claim 2 or 4, wherein: The adhesive layer contains a plurality of types of conductive fillers having different electrical conductivities as the conductive filler.

8. The superconducting coil device according to claim 5, wherein: An inter-turn insulating portion is provided in a region sandwiched between each pair of the turn portions adjacent to each other.

9. The superconducting coil device according to claim 5, wherein: The superconducting coil has a structure in which the superconducting wire is wound around the central axis of the superconducting coil while being transferred in the axial direction of the superconducting coil. The superconducting wire is a single continuous superconducting wire or a plurality of superconducting wires connected in series, and this configuration is regarded as one coil layer, and a plurality of coil layers are formed which are arranged in a radial direction of the superconducting coil. The current bypass path is formed for each of the plurality of coil layers.

10. The superconducting coil device according to claim 9, wherein: An interlayer insulating portion is provided between inner and outer coil layers adjacent to each other in the radial direction and electrically insulates the coil layers from each other.

11. The superconducting coil device according to claim 9, wherein: The superconducting wire is extended around the central axis of the superconducting coil while being transferred axially from one axial end to the other axial end to form an inner coil layer, and then, on the radially outer side of the inner coil layer, is extended around the central axis while being transferred axially from the other axial end to one axial end to form an outer coil layer. An interlayer current bypass path is formed to electrically connect one or more turn portions of the inner coil layer located at the other axial end and one or more turn portions of the outer coil layer located at the other axial end.

12. The superconducting coil device according to claim 11, wherein: The interlayer current bypass path is composed of a portion of the adhesive material layer, a portion of the conductor portion, and an interlayer conductor portion. The portion of the adhesive material layer is sandwiched in the radial direction by the other axial end portion of the inner coil layer and the other axial end portion of the outer coil layer. The portion of the conductor portion is sandwiched in the radial direction by the other axial end portion of the inner coil layer and the other axial end portion of the outer coil layer. The interlayer conductor portion electrically connects the portion of the conductor portion to the other axial end portion of the inner or outer coil layer.

13. The superconducting coil device according to claim 9, wherein: Regarding each coil layer, the adhesive material layer extends in the axial direction and the circumferential direction of the superconducting coil in a manner that contacts the outer circumferential surface or the inner circumferential surface of the multiple turn portions of the superconducting wire forming the coil layer, and the conductor portion extends in the axial direction and the circumferential direction in a manner that contacts the outer circumferential surface or the inner circumferential surface of the adhesive material layer.

14. The superconducting coil device according to claim 5, wherein: The superconducting coil has a structure in which the superconducting wire is wound around the central axis of the superconducting coil while being shifted radially outward while maintaining a constant position in the axial direction of the superconducting coil. The superconducting wire is a single continuous superconducting wire or a plurality of superconducting wires connected in series, and this configuration is regarded as one coil layer, and a plurality of coil layers are formed arranged in the axial direction of the superconducting coil. The current bypass path is formed for each of the plurality of coil layers.

15. The superconducting coil device according to claim 14, wherein: An interlayer insulating portion is provided between coil layers adjacent to each other in the axial direction and electrically insulates the coil layers from each other.

16. The superconducting coil device according to claim 14, wherein: The coil layers adjacent to each other in the axial direction include an interlayer conductor portion electrically connecting a radially innermost or outermost turn portion of one coil layer to a radially innermost or outermost turn portion of the other coil layer.

17. The superconducting coil device according to claim 16, wherein: For the coil layers adjacent to each other in the axial direction, The superconducting wire forms an interlayer turn portion by continuously extending from a position constituting the innermost or outermost turn portion in one coil layer while further extending in the circumferential direction of the superconducting coil while shifting inward or outward in the radial direction and shifting toward the other coil layer side in the axial direction, and then reaches a position constituting the innermost or outermost turn portion in the other coil layer by continuously extending inward or inward in the radial direction while shifting toward the other coil layer side in the axial direction. The interlayer conductor portion is electrically connected to the interlayer turn portion.

18. The superconducting coil device according to any one of claims 1 to 4, wherein: The superconducting coil has a structure in which the superconducting wire is wound around the central axis of the superconducting coil while being shifted radially outward while maintaining a constant position in the axial direction of the superconducting coil. The adhesive layer is provided between each pair of turn portions adjacent to each other in the radial direction in the superconducting coil to form a current bypass path that electrically connects the turn portions to each other.

19. The superconducting coil device according to any one of claims 1 to 4, wherein: The superconducting wire is configured to include a superconducting layer of a high-temperature superconductor or a low-temperature superconductor.

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