Superconducting coil and method for manufacturing the same, and superconducting flat wire rod for superconducting coil

Abstract

To provide a superconducting flat wire rod for manufacturing, with a simple method, a superconducting coil that prevents quenching without performing processing of impregnation and curing using a resin, a superconducting coil obtained by using the same, and a method for manufacturing the same.SOLUTION: A superconducting coil 100 comprises: a bobbin 60; and at least two superconducting flat wire rod layers L1, L2 that are formed by winding, on the outer peripheral surface of the bobbin, a superconducting flat wire rod 10' including an NbTi-based or Nb3Sn-based wire rod having its surface coated with copper or a copper alloy and having a substantially rectangular section, in a spiral form along a substantially circumferential direction of the bobbin, so that wire rods adjacent in an axial direction of the bobbin are arranged in parallel while being separated from each other. The superconducting flat wire rods adjacent to each other have at least a thermoplastic fusion resin 2' in their separation part. Gaps 41-48 partitioned and formed by a total of three or four superconducting flat wire rods adjacent to each other have porosity of 4% or less, which is the area ratio accounted for in the at least two superconducting flat wire rods.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a superconducting coil, a manufacturing method thereof, and a rectangular superconducting wire for a superconducting coil. [Background technology]

[0002] It is generally known that superconducting wires exhibit superconducting properties at extremely low temperatures. Such superconducting wires can be used as electromagnets by winding them around a spool to form a coil and then immersing them in liquid helium. Although superconducting wires have the advantage of being able to carry a significantly larger current than ordinary electric wires such as copper wires, when a large current is passed through them, a large electromagnetic force is applied, which may cause vibration and heat generation. If the temperature rises due to heat generation, the superconducting state is destroyed and the wire becomes a normal conducting state (hereinafter referred to as "quench") even when a current smaller than the critical current value of the superconducting wire is passed through it, causing problems such as the liquid helium evaporating all at once. Therefore, it is necessary to take measures to maintain the superconducting state and prevent quenching.

[0003] As a means for preventing this quench, for example, Patent Document 1 discloses a superconducting coil in which the windings of the superconducting coil are impregnated with epoxy resin and then the epoxy resin is cured and fixed. The cured epoxy resin does not easily suffer damage such as cracks or peeling even when subjected to repeated heat cycles between room temperature and cryogenic temperatures (up to 4K), but if damage does occur, it becomes more susceptible to quenching. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 06-325932 Summary of the Invention [Problem to be solved by the invention]

[0005] However, since the above-mentioned fixation of the superconducting rectangular wire by impregnation with epoxy resin and hardening process is costly and time-consuming, there has been a demand for a simpler method for manufacturing a superconducting coil capable of preventing quenching, and for a superconducting rectangular wire.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a superconducting rectangular wire for manufacturing a superconducting coil capable of preventing quenching in a simple manner without the need for resin impregnation and hardening processes, a superconducting coil obtained using the same, and a manufacturing method thereof. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, they have developed a NbTi or Nb 3 The inventors have found that a superconducting rectangular wire for a superconducting coil has a Sn-based wire and a fusion resin layer made of a thermoplastic fusion resin that coats the outer circumferential surface of the wire, and that by optimizing the average coating thickness of the fusion resin layer that constitutes the superconducting rectangular wire and the curvature radius of the corners of the superconducting rectangular wire, and by producing a superconducting coil using the superconducting rectangular wire, quenching can be effectively suppressed, leading to the completion of the present invention. Specifically, the present invention provides the following.

[0008] [1] A reel and a NbTi or Nb coated with copper or a copper alloy on the outer circumferential surface of the reel. 3A superconducting coil comprising at least two superconducting rectangular wire layers formed by spirally winding a superconducting rectangular wire containing Sn-based wire and having a substantially rectangular cross section in a substantially circumferential direction of the reel, so that adjacent wires in the axial direction of the reel are arranged parallel to each other while being spaced apart from each other, wherein at least a thermoplastic fusion resin is present in the space between adjacent wires in the same superconducting rectangular wire layer and in the space between adjacent wires located in each of two adjacent superconducting rectangular wire layers, and wherein at least one of the voids that can be formed on the outer surfaces of a total of three superconducting rectangular wires located in the two adjacent superconducting rectangular wire layers and adjacent to each other, when viewed in a cross section including the axis of the reel, is 4% or less in terms of a void ratio (V1), which is an area ratio of the at least two superconducting rectangular wire layers. [2] The superconducting coil described in [1] above, characterized in that the voids are located in the two adjacent superconducting rectangular wire layers and are defined and formed by the outer surfaces of a total of three or four adjacent superconducting rectangular wires when viewed in a cross section including the axis of the winding frame. [3] A reel and a NbTi or Nb coated with copper or a copper alloy on the outer circumferential surface of the reel. 3 A superconducting coil comprising: a superconducting flat wire layer formed by spirally winding a superconducting flat wire material including Sn-based wire material and having a substantially rectangular cross section along a substantially circumferential direction of the reel, so that adjacent wire materials in the axial direction of the reel are arranged parallel to each other and spaced apart from each other; wherein at least a thermoplastic fusion resin is present in the space between adjacent wire materials in the superconducting flat wire layer; and wherein, when viewed in a cross section including the axis of the reel, voids that can be partitioned and formed on the outer surfaces of a total of two adjacent superconducting flat wire materials have a void ratio (V1), which is the area ratio of the superconducting flat wire material layer, of 4% or less. [4] A superconducting coil according to any one of [1] to [3] above, characterized in that the superconducting rectangular wire has a fusion resin layer made of the thermoplastic fusion resin that covers the outer surface of the wire. [5] The superconducting coil according to any one of the above [1] to [4], wherein the thermoplastic fusion resin is one or more selected from the group consisting of phenoxy resin, polyamide resin, and polyester resin. [6] A superconducting coil according to the above [4] or [5], characterized in that the superconducting rectangular wire further has an insulating resin layer between the outer surface of the wire and the fusion resin layer. [7] The superconducting coil according to [6] above, wherein the insulating resin layer is made of one or more resins selected from the group consisting of polyvinyl formal resin, polyamideimide resin, polyimide resin, polyester resin and polyurethane resin. [8] The superconducting coil according to [6] or [7] above, wherein the average coating thickness of the insulating resin layer is 0.005 mm or more and 0.100 mm or less. [9] The superconducting coil according to any one of the above [1] to [8], wherein the wire is a rectangular wire and the radius of curvature (R1) of the corners is 0.1 mm or more and 0.4 mm or less.

[10] A superconducting coil according to any one of the above [1] to [9], characterized in that the wire is a rectangular wire and the radius of curvature (R1) of the corners satisfies the following formulas (1) and (2).

number

[11] NbTi or Nb with copper or copper alloy surface coating 3 A superconducting rectangular wire for a superconducting coil, comprising an Sn-based wire and a fusion resin layer made of a thermoplastic fusion resin that coats the outer surface of the wire, wherein the average coating thickness of the fusion resin layer is 0.005 mm or more and 0.100 mm or less, and the radius of curvature (R2) of the corners of the superconducting rectangular wire satisfies the following formulas (3) and (4).

number

[12] The superconducting rectangular wire according to the above

[11] , wherein the average coating thickness of the fusion resin layer is 0.01 mm or more and 0.07 mm or less.

[13] The superconducting rectangular wire according to the above

[11] or

[12] , characterized in that the thermoplastic fusion resin is one or more selected from the group consisting of phenoxy resin, polyamide resin and polyester resin.

[14] The superconducting rectangular wire according to any one of the above

[10] to

[13] , further comprising an insulating resin layer made of an insulating resin between an outer peripheral surface of the wire and the fusion resin layer.

[15] The superconducting rectangular wire according to

[14] above, wherein the insulating resin is one or more selected from the group consisting of polyvinyl formal resin, polyamideimide resin, polyimide resin, polyester resin and polyurethane resin.

[16] The superconducting rectangular wire according to the above

[14] or

[15] , wherein the average coating thickness of the insulating resin layer is 0.005 mm or more and 0.100 mm or less.

[17] The superconducting rectangular wire according to any one of the above

[11] to

[16] , characterized in that the wire is a rectangular wire and the radius of curvature (R1) of the corners is 0.1 mm or more and 0.4 mm or less.

[18] The superconducting rectangular wire according to any one of the above

[11] to

[17] , characterized in that the wire is a rectangular wire and the radius of curvature (R1) of the corners satisfies the following formulas (1) and (2).

number

[19] A method for manufacturing a superconducting coil, comprising: a winding step of spirally winding the superconducting flat wire according to any one of

[10] to

[18] above on an outer peripheral surface of a reel along an approximate circumferential direction of the reel to form a coil having at least two superconducting flat wire layers in which adjacent wires in the axial direction of the reel are arranged parallel to each other while being spaced apart from each other; and a heat treatment step of heat treating the coil formed in the winding step at a temperature equal to or higher than the glass transition temperature of the amorphous resin and equal to or lower than 300°C when the thermoplastic fusion resin is an amorphous resin, or at a temperature equal to or higher than the melting point of the crystalline resin and equal to or lower than 300°C when the thermoplastic fusion resin is a crystalline resin.

[20] A method for manufacturing a superconducting coil, comprising: a winding step of spirally winding the superconducting flat wire according to any one of

[10] to

[18] above on an outer peripheral surface of a reel along an approximate circumferential direction of the reel to form a coil having one layer of superconducting flat wire in which adjacent wires in the axial direction of the reel are arranged in parallel and spaced apart from each other; and a heat treatment step of heat treating the coil formed in the winding step at a temperature equal to or higher than the glass transition temperature of the amorphous resin and equal to or lower than 300°C when the thermoplastic fusion resin is an amorphous resin, or at a temperature equal to or higher than the melting point of the crystalline resin and equal to or lower than 300°C when the thermoplastic fusion resin is a crystalline resin. Effect of the Invention

[0009] According to the present invention, it is possible to provide a superconducting rectangular wire for manufacturing a superconducting coil capable of preventing quenching in a simple manner without carrying out a process of impregnation and hardening with a resin, a superconducting coil obtained using the same, and a manufacturing method thereof. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view of a superconducting coil according to a first embodiment, taken along a plane including the axis of a bobbin. [Diagram 2] FIG. 2 is a diagram for explaining a method of calculating the void ratio (V1) in the superconducting coil of FIG. [Diagram 3] FIG. 3 is a cross-sectional view for explaining the positional relationship between two adjacent superconducting rectangular wire layers which constitute the superconducting coil of the second embodiment. [Figure 4] FIG. 4 is a cross-sectional view for explaining the positional relationship between two adjacent superconducting rectangular wire layers which constitute the superconducting coil of the third embodiment. [Diagram 5] FIG. 5 is a cross-sectional view of a superconducting coil according to the fourth embodiment, taken along a plane including the axis of the bobbin. [Figure 6] FIG. 6 is a diagram for explaining a method of calculating the void ratio (V1) in the superconducting coil of FIG. [Figure 7]FIG. 7 is a cross-sectional view of the rectangular superconducting wire for a superconducting coil according to the first embodiment. [Figure 8] FIG. 8 is a cross-sectional view of a rectangular superconducting wire for a superconducting coil according to the second embodiment. [Figure 9] FIG. 9 is a diagram for explaining an example of a method for manufacturing a superconducting coil. [Figure 10] FIG. 10 is a diagram for explaining another example of the method for manufacturing a superconducting coil. [Figure 11] FIG. 11 is a cross-sectional view for explaining the dimensions of a superconducting rectangular wire for a superconducting coil manufactured in an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Preferred embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments.

[0012] 1. Superconducting coil The superconducting coil according to the present invention is a coil comprising a spool and a NbTi or Nb alloy coated on the outer circumferential surface of the spool. 3 A superconducting coil comprising at least two superconducting rectangular wire layers formed by spirally winding a superconducting rectangular wire containing Sn-based wire and having a substantially rectangular cross section along a substantially circumferential direction of a reel so that adjacent wires in the axial direction of the reel are arranged parallel to each other while being spaced apart from each other, wherein at least a thermoplastic fusion resin is present in the space between adjacent wires in the same superconducting rectangular wire layer and in the space between adjacent wires located in each of two adjacent superconducting rectangular wire layers, and wherein at least one of the voids that can be formed on the outer surfaces of a total of three superconducting rectangular wires located in two adjacent superconducting rectangular wire layers and adjacent to each other, as viewed in a cross section including the axis of the reel, is 4% or less in terms of void ratio (V1), which is the area ratio of the at least two superconducting rectangular wire layers.

[0013] The superconducting coil according to the present invention is made of a spool and a NbTi or Nb alloy coated on the outer circumferential surface of the spool. 3 A superconducting coil comprising one layer of superconducting rectangular wire formed by spirally winding a superconducting rectangular wire containing Sn-based wire and having a substantially rectangular cross section approximately along the circumferential direction of a reel so that adjacent wires in the axial direction of the reel are arranged parallel to each other and spaced apart from each other, wherein at least a thermoplastic fusion resin is present in the space between adjacent wires in the superconducting rectangular wire layer, and when viewed in a cross section including the axis of the reel, the voids that can be formed on the outer surfaces of a total of two adjacent superconducting rectangular wires are 4% or less in terms of void ratio (V1), which is the area ratio of the superconducting rectangular wire layer.

[0014] 1 is a cross-sectional view of a superconducting coil according to a first embodiment, cut along a plane including the axis of a bobbin. The superconducting coil 100 shown in FIG. 1 includes a bobbin 60 and a NbTi or Nb 3 The superconducting coil 100 includes two superconducting flat wire layers L1 and L2, which are formed by spirally winding a superconducting flat wire 10' having a substantially rectangular cross section, substantially along the circumferential direction of the winding frame 60, so that the wires 1' adjacent to each other in the axial direction of the winding frame are arranged parallel to each other while being spaced apart from each other. The superconducting flat wire layers L1 and L2 are laminated in the radial direction of the winding frame 60. The superconducting flat wire layer L1 is provided on the outside of the superconducting flat wire layer L2, and the superconducting flat wire layer L2 is provided on the outer peripheral surface of the winding frame 60 inside the superconducting flat wire layer L1. In the following, an example in which the superconducting coil 100 includes two superconducting flat wire layers L1 and L2 will be described, but the superconducting coil 100 may include three or more superconducting flat wire layers.

[0015] The reel 60 includes, for example, a solid or hollow cylindrical body 61, and flange-like flanges 62, 63 provided at both axial ends of the body 61. The wire 1' is wound around the outer circumferential surface of the body 61 of the reel 60. In a cross-sectional view taken along a plane including the axis of the reel shown in FIG 1, i.e., a vertical cross-sectional view of the superconducting coil including the axis of the reel, the outer circumferential surface of the body 61 corresponds to an outer circumferential line 61a described below.

[0016] At least the thermoplastic fusion resin 2' is present in the spaced apart portion S1 between adjacent wires 1'-1, 1'-2 in the axial direction of the reel within the same superconducting rectangular wire layer L1 or L2, and in the spaced apart portion S2 between adjacent wires 1'-1, 1'-6 in the radial direction of the reel and located in two adjacent superconducting rectangular wire layers L1, L2, respectively. In other words, the surface of the wire 1' is completely covered with the thermoplastic fusion resin 2', and the wires 1' do not come into contact with each other. When viewed in a cross section including the axis of this reel 60, at least one of the voids that can be formed on the outer surfaces of a total of three superconducting flat wire materials located in two adjacent superconducting flat wire layers and adjacent to each other in the axial or radial direction of the reel and the voids that can be formed on the outer surfaces of a total of four superconducting flat wire materials has a void ratio (V1), which is the area ratio of the two superconducting flat wire layers L1, L2, of 4% or less.

[0017] The voids that can be defined and formed on the outer surfaces of a total of three superconducting rectangular wires are void 41 that can be defined and formed on the outer surfaces of a total of three superconducting rectangular wires 1'-1, 1'-2, and 1'-6, and voids 42, ..., and void 48 that can be defined and formed on the outer surfaces of a total of three superconducting rectangular wires 1'-2, 1'-6, and 1'-7, as shown in Fig. 1. Also, the voids that can be defined and formed on the outer surfaces of a total of four superconducting rectangular wires are void 41b that can be defined and formed on the outer surfaces of a total of four superconducting rectangular wires 1b'-1, 1b'-2, 1b'-6, and 1b'-7, and voids 42b, ..., and void 44b that can be defined and formed on the outer surfaces of a total of four superconducting rectangular wires 1'-2, 1b'-3, 1'-7, and 1'-8, as shown in Fig. 4 described later.

[0018] In the cross section including the axis of the reel 60, the voids may be only voids that can be partitioned and formed on the outer surfaces of a total of three superconducting rectangular wires, or may be only voids that can be partitioned and formed on the outer surfaces of a total of four superconducting rectangular wires, or may be voids (mixed) that can be partitioned and formed on the outer surfaces of a total of three and a total of four superconducting rectangular wires. In the superconducting coil 100, if the angle of the plane including the axis of the reel 60 with respect to the axis of the reel 60 is different, the state of the voids in the cross section including the axis of the reel 60 may change. For example, in the superconducting coil 100, in one cross section including the axis of the reel 60, only voids that can be partitioned and formed on the outer surfaces of a total of three superconducting rectangular wires may be seen, and in another cross section including the axis of the reel 60, only voids that can be partitioned and formed on the outer surfaces of a total of four superconducting rectangular wires may be seen.

[0019] Here, a method for calculating the area (S) of at least two superconducting rectangular wire layers in calculating the void ratio (V1) will be described. As shown in FIG. 2, when viewed in a cross section including the axis of the reel, of the straight lines tangent to or intersecting with all of the superconducting rectangular wires 10' constituting the superconducting rectangular wire layer L1, which is the outermost layer, the line furthest from the outer peripheral line 61a is defined as line P. As shown in FIG. 2, for example, line P is parallel to the outer peripheral line 61a and tangent to all of the superconducting rectangular wires 10' constituting the superconducting rectangular wire layer L1. The area surrounded by line P, the outer peripheral line 61a of the body 61 of the reel 60, and the flanges 62, 63 of the reel 60 is defined as area (S) (the area indicated by the dotted line in FIG. 2). On the other hand, the area (S v 1 and 41b, 42b, . . . 48b shown in FIG. 4. The gaps 51, 52 (shown as areas surrounded by two-dot chain lines in FIG. 1) formed between the flanges 62, 63 of the reel 60 and the side surfaces of the superconducting rectangular wire layers L1, L2 facing the flanges 62, 63, respectively, are defined by the area (S v ), and all inner voids 71 ​​formed between the superconducting rectangular wire layer L2 and the outer peripheral wire 61a of the body of the spool, and all outer voids 72 formed between the superconducting rectangular wire layer L1, which is the outermost layer, and the wire P, are not added to the void area (S v) and the porosity (V1) is V1(%)=(S v / S) × 100. From the viewpoint of suppressing quenching, it is preferable that the gaps 51 and 52 are filled with a resin such as a thermoplastic fusion resin.

[0020] With such a superconducting coil 100, quenching can be effectively prevented even when a large current is passed through the superconducting coil 100. Furthermore, cracks do not occur in the thermoplastic fusion resin 2' due to thermal stress that occurs when the coil is repeatedly heated and cooled or during quenching, and the number of training quenches is reduced, making it possible to use the superconducting coil with high stability.

[0021] [Superconducting rectangular wire] The superconducting rectangular wire 10' has at least a wire 1' described below and a fusion resin layer 2' made of a thermoplastic fusion resin that covers the outer surface of the wire 1', and optionally an insulating resin may be provided between them.

[0022] In the superconducting coil 100, the direction in which the superconducting rectangular wire 10' is wound around the bobbin 60 is not particularly limited, and may be either right-handed or left-handed.

[0023] The number of turns of the superconducting rectangular wire 10' around the bobbin 60 is not particularly limited.

[0024] The number of superconducting rectangular wire layers on the reel 60 is not particularly limited as long as it is at least one layer.

[0025] [Wire rod] The wire 1' is made of NbTi or Nb with a surface coated with copper or copper alloy. 3 This is a Sn-based wire.

[0026] The shape of the wire 1' is not particularly limited, and for example, a circular wire or a rectangular wire can be used. Among them, by using a rectangular wire, the gap can be made smaller, and a higher current density can be obtained. Furthermore, when manufacturing by the manufacturing method described later, the fusion area (contact area) between the wires becomes larger, and therefore the fusion force can be increased.

[0027] When a rectangular wire is used as the wire 1', the radius of curvature (R1) of the corners in the cross section (i.e., the cross section including the axis of the superconducting coil bobbin) is preferably 0.1 mm or more and 0.4 mm or less. By making the radius of curvature (R1) of the corners 0.1 mm or more, it is possible to prevent the wires from getting caught on each other and causing scratches on the surface of the wire when winding the superconducting coil, and by making it 0.4 mm or less, it is possible to reduce the void ratio in the superconducting coil.

[0028] When a rectangular wire is used as the wire 1', the thickness (short side) of the cross section of the wire 1' is not particularly limited, but is, for example, 0.2 mm or more and 3 mm or less, and the width (long side) is not particularly limited, but is, for example, 0.4 mm or more and 10 mm or less.

[0029] When a rectangular wire is used as the wire 1', it is preferable that the radius of curvature (R1) of the corner of the wire 1' satisfies the following formulas (1) and (2). In formula (2), A is 0.06, and preferably 0.04.

number

[0030] [Fusing resin layer] The adhesive resin layer 2' covers the outer peripheral surface of the wire 1' and is made of a thermoplastic adhesive resin, which can be fused to each other by heating.

[0031] The thermoplastic fusion resin is not particularly limited, but it is preferable to use one or more selected from phenoxy resin, polyamide resin, and polyester resin, since fusion processing can be performed under relatively low temperature conditions and good fusion properties can be expected.

[0032] The above-mentioned phenoxy resin is also called polyhydroxy ether, has a molecular weight of 10,000 or more, and has a chemical structure shown below as formula (a). Although not particularly limited, the phenoxy resin used in the present invention can be used as a varnish dissolved in a solvent such as m-cresol. [ka]

[0033] The polyamide resin is preferably a polyamide random copolymer having a relatively low melting point compared to a polyamide unit, such as polyamide 6 / polyamide 12 copolymer, polyamide 6 / polyamide 11 copolymer, and polyamide 6 / polyamide 66 copolymer, among which polyamide 6 / polyamide 12 copolymer and polyamide 6 / polyamide 11 copolymer are more preferable due to their low melting points. The melting point of the polyamide copolymer varies depending on the composition ratio of each resin, and the composition ratio having the lowest melting point can be selected and used. For example, in the case of polyamide 6 / polyamide 11 copolymer, when polyamide 6 is 30% by weight, the melting point is 150°C, which is the lowest. Although not particularly limited, the polyamide resin used in the present invention can be used as a varnish dissolved in a solvent such as m-cresol.

[0034] [Insulating resin layer] Although not an essential component, it is preferable to further have an insulating resin layer made of insulating resin between the outer peripheral surface of the wire and the fusion resin layer in order to further improve insulation from the wire to the outside.

[0035] Fig. 3 is a cross-sectional view of the superconducting flat wire layer portion of the superconducting coil of the second embodiment. Fig. 3 is a cross-sectional view including the axis of the reel, omitting the reel and showing only the cross-sectional view of the superconducting flat wire layer portion on one side. The fusion resin layer 2a' is fusion-bonded. An insulating resin layer 3a is disposed between the outer peripheral surface of this wire 1a'-1 and the fusion resin layer 2a'. The surface of the wire 1a' is completely covered with the insulating resin layer 3a.

[0036] The insulating resin is not particularly limited as long as it can insulate the flow of electricity from the wire 1a'-1 to the outside. The insulating resin layer is preferably made of one or more resins selected from polyvinyl formal resin, polyamideimide resin, polyimide resin, polyester resin, and polyurethane resin, which are expected to have relatively good insulating properties.

[0037] The average coating thickness of the insulating resin layer 3a is not particularly limited, but is preferably 0.005 mm or more, more preferably 0.01 mm or more, in order to ensure the insulating properties. The average coating thickness of the insulating resin layer 3a is preferably 0.100 mm or less, more preferably 0.07 mm or less, and even more preferably 0.05 mm or less. If the average coating thickness of the insulating resin layer is less than 0.005 mm, sufficient insulating properties cannot be expected due to insufficient resin amount, and if it is thicker than 0.100 mm, the wire space factor decreases and the current density of the coil decreases, which is not preferable. The average coating thickness of the insulating resin layer 3a is measured at the end (part not sandwiched between wires) of the cross section when cut on a plane including the axis of the reel 60.

[0038] Meanwhile, as shown in Figures 1 and 3, in a superconducting coil in which voids 41 are located in two adjacent superconducting flat wire layers L1, L2 and are defined by the outer surfaces of a total of three adjacent superconducting flat wires (for example, superconducting flat wires 1'-1, 1'-2, 1'-6) when viewed in a cross section including the axis of the reel, compared to a superconducting coil (Figure 4) in which voids are defined by the outer surfaces of a total of four superconducting flat wires, the voids 41, 42, ..., 48 are not aligned linearly along the radial direction of the reel, but are arranged alternately inward and outward in the radial direction of the reel. 1 and 3, the positions of the corners of the superconducting rectangular wire 10' or wire 1' constituting the superconducting rectangular wire layer L1 and the positions of the corners of the superconducting rectangular wire 10' or wire 1' constituting the superconducting rectangular wire layer L2 adjacent to the superconducting rectangular wire layer L1 on the radially inner side of the reel are completely offset from each other in the axial direction of the reel. Therefore, the propagation of cracks in the gaps is effectively suppressed, and the mechanical strength is increased.

[0039] However, as shown in Figure 4, when void 41b is located in two adjacent superconducting flat wire layers L1b, L2b and is formed on the outer surfaces of a total of four adjacent superconducting flat wires (for example, superconducting flat wires 1b'-1, 1b'-2, 1b'-6, and 1b'-7) when viewed in a cross section including the axis of the reel, voids 41b, 42b, 43b, and 44b are arranged in a straight line along the radial direction of the reel, but have sufficient strength to withstand normal use of the superconducting coil.

[0040] Fig. 5 is a cross-sectional view of the superconducting coil of the fourth embodiment cut along a plane including the axis of the bobbin. Fig. 6 is a diagram for explaining a method for calculating the void ratio (V1) in the superconducting coil of Fig. 5. In the above, a superconducting coil having at least two superconducting rectangular wire layers L1, L2 (L1b, L2b) on the outer peripheral wire 61a of the trunk 61 of the bobbin 60 is shown, but the superconducting coil 100 of this embodiment has only one superconducting rectangular wire layer L2 on the outer peripheral wire 61a of the trunk 61. Also, similarly to the above, the superconducting coil 100 shown in Figs. 5-6 may have an insulating resin layer 3a.

[0041] The superconducting coil 100 shown in FIGS. 5 and 6 comprises a winding frame 60 and a NbTi or Nb 3 The superconducting flat wire layer L2 is formed by spirally winding a superconducting flat wire 10' having a substantially rectangular cross section, including a Sn-based wire 1', substantially along the circumferential direction of a reel 60, so that adjacent wires 1' in the axial direction of the reel are arranged parallel to each other but spaced apart from each other.

[0042] In the superconducting rectangular wire layer L2, at least the thermoplastic fusion resin 2' is present in the spaced apart portion S1 between the wires 1'-6, 1'-7 adjacent in the axial direction of the reel. That is, the surface of the wire 1' is completely covered with the thermoplastic fusion resin 2', and the wires 1' do not come into contact with each other. When viewed in a cross section including the axis of this reel 60, the voids that can be defined and formed on the outer surfaces of the two superconducting rectangular wires adjacent to each other in the axial direction of the reel are expressed as a void ratio (V1), which is the area ratio of one layer of the superconducting rectangular wire layer L2, of 4% or less.

[0043] Here, a method for calculating the area (S) of one superconducting rectangular wire layer in calculating the void ratio (V1) in this embodiment will be described. As shown in FIG. 6, when viewed in a cross section including the axis of the reel, among the straight lines tangent to or intersecting with all of the superconducting rectangular wires 10' constituting the superconducting rectangular wire layer L2, the line furthest from the outer circumferential line 61a is taken as line P. Line P is parallel to the outer circumferential line 61a, for example, as shown in FIG. 6, and is a line tangent to all of the superconducting rectangular wires 10' constituting the superconducting rectangular wire layer L2. The area surrounded by line P, the outer circumferential line 61a of the body 61 of the reel 60, and the flanges 62, 63 of the reel 60 is taken as area (S) (the area indicated by the dotted line in FIG. 6). On the other hand, the area (S v) is the sum of all the inner gaps 71 formed between the superconducting rectangular wire layer L2 and the outer peripheral wire 61a of the body of the reel, and all the outer gaps 72 formed between the superconducting rectangular wire layer L2 and the wire P. The gap 51 formed between the two flanges 62, 63 of the reel 60 and both side surfaces of the superconducting rectangular wire layer L2 facing each of these flanges 62, 63 (here, the gap 51 is formed between the flange 62 and the side surface of the superconducting rectangular wire layer L2, and is not formed between the flange 63 and the side surface of the superconducting rectangular wire layer L2) is the sum of the area (S v ) is not added. And the porosity (V1) is V1 (%) = (S v / S) × 100. From the viewpoint of suppressing quenching, it is preferable that the gap 51 is filled with a resin such as a thermoplastic fusion resin.

[0044] According to such a single-layer type superconducting coil 100, like the above-mentioned multi-layer type superconducting coil, quenching can be effectively prevented even when a large current is passed through the superconducting coil 100, and further, cracks do not occur in the thermoplastic fusion resin 2' due to thermal stress generated when the coil is repeatedly heated and cooled or during quenching, so that the number of training quenches is reduced and the superconducting coil can be used as a highly stable superconducting coil.

[0045] 2. Superconducting rectangular wire for superconducting coils The superconducting rectangular wire for superconducting coils of the present invention is a NbTi or Nb 3 A superconducting rectangular wire for a superconducting coil has a Sn-based wire and a fusion resin layer made of a thermoplastic fusion resin that coats the outer circumferential surface of the wire, the fusion resin layer has an average coating thickness of 0.005 mm to 0.100 mm, and the radius of curvature (R2) of the corners of the superconducting rectangular wire satisfies the following formulas (3) and (4): B in formula (3) is 0.06, and preferably 0.04.

number

[0046] 7 is a cross-sectional view of a rectangular superconducting wire for a superconducting coil according to a first embodiment of the present invention. The rectangular superconducting wire for a superconducting coil 10 is a NbTi or Nb 3 The wire 1 has a Sn-based wire and a fusion resin layer 2 made of a thermoplastic fusion resin that covers the outer peripheral surface of the wire 1, the fusion resin layer 2 has an average coating thickness of 0.005 mm or more and 0.100 mm or less, and the radius of curvature (R2) of the corners of the superconducting rectangular wire 10 satisfies the above formulas (3) and (4). The cross section of the superconducting rectangular wire 10 is a rectangular wire having a substantially rectangular shape.

[0047] Such a superconducting flat wire 10 is spirally wound on the outer peripheral surface of the reel approximately in the circumferential direction of the reel to form a coil having at least two superconducting flat wire layers in which adjacent wires 1, 1 in the axial direction of the reel are arranged parallel to each other with a space between them, and a heat treatment process is performed on the coil formed in the winding process at a temperature equal to or higher than the glass transition temperature of the amorphous resin (preferably a temperature 30°C higher than the glass transition temperature) and equal to or lower than 300°C if the thermoplastic fusion resin is an amorphous resin, or at a temperature equal to or higher than the melting point of the crystalline resin and equal to or lower than 300°C if the thermoplastic fusion resin is a crystalline resin. By going through a simple method including this, since the outer peripheral surface of the superconducting flat wire 10 is already coated with the fusion resin layer 2, a superconducting coil 100 that can prevent quenching can be easily manufactured with simple operations without performing impregnation and hardening processes using resin. If the fusion treatment temperature exceeds 300° C., the performance of the superconducting wire may be deteriorated due to heating, which is undesirable.

[0048] In particular, when the average coating thickness of the fusion resin layer 2 is 0.005 mm or more and 0.100 mm or less, and the radius of curvature (R2) of the corners of the superconducting flat rectangular wire 10 satisfies the above formulas (3) and (4), the void ratio (V1) of the superconducting coil manufactured using the superconducting flat rectangular wire 10 is 4% or less, and as a result, quenching of the superconducting coil 100 can be prevented.

[0049] [Wire rod] The wire 1 is similar to the wire used in the above-mentioned superconducting coil, and therefore a description thereof will be omitted here.

[0050] [Fusing resin layer] The fusion resin layer 2 is a layer made of the same resin as the thermoplastic fusion resin used in the above-mentioned superconducting coil, and covers the outer circumferential surface of the wire 1 .

[0051] Specifically, the thermoplastic fusion resin constituting this fusion resin layer 2 is not particularly limited, but from the viewpoint that fusion processing can be performed under relatively low temperature conditions and good fusion characteristics can be expected, it is preferable to use one or more types selected from phenoxy resin, polyamide resin, and polyester resin.

[0052] The average coating thickness of the fusion resin layer 2 is not particularly limited as long as it is 0.005 mm or more and 0.100 mm or less, but is preferably 0.01 mm or more. The average coating thickness of the fusion resin layer 2 is preferably 0.07 mm or less, and more preferably 0.05 mm or less. If the average coating thickness of the fusion resin layer 2 is less than 0.005 mm, sufficient fusion force cannot be expected due to insufficient resin amount, while if the average coating thickness is thicker than 0.100 mm, the wire space factor decreases and the current density of the coil may decrease, which is not preferable. The average coating thickness of the fusion resin layer 2 when the superconducting coil 100 is constructed is measured at the end (part not sandwiched between wires) of the cross section when cut on a plane including the axis of the reel 60.

[0053] [Insulating resin layer] Although not an essential component, it is preferable to further have an insulating resin layer made of insulating resin between the outer peripheral surface of the wire and the fusion resin layer in order to further improve insulation from the wire to the outside.

[0054] 8 is a cross-sectional view of a rectangular superconducting wire for a superconducting coil according to a second embodiment of the present invention. In FIG. 8, a rectangular superconducting wire 10a further includes an insulating resin layer 3a between an outer peripheral surface of wire 1a and fusion resin layer 2a.

[0055] The insulating resin layer 3a is not particularly limited as long as it can insulate the flow of electricity from the wire 1a to the outside. From the viewpoint of being expected to have relatively good insulating properties, the insulating resin layer 3a is preferably made of one or more resins selected from polyvinyl formal resin, polyamideimide resin, polyimide resin, polyester resin, and polyurethane resin.

[0056] The average coating thickness of the insulating resin layer 3a is not particularly limited, but is preferably 0.005 mm or more, more preferably 0.01 mm or more, in order to ensure the insulating properties. The average coating thickness of the insulating resin layer 3a is preferably 0.100 mm or less, more preferably 0.07 mm or less, and even more preferably 0.05 mm or less. If the average coating thickness of the insulating resin layer is less than 0.005 mm, the amount of resin is insufficient, so sufficient insulating properties cannot be expected, and if it is thicker than 0.100 mm, the wire space factor decreases, and the current density of the coil decreases, which is not preferable. The average coating thickness of the insulating resin layer 3a when the superconducting coil 100 is constructed is measured at the end (the part not sandwiched between the wires) of the cross section when the insulating resin layer 3a is cut along a plane including the axis of the reel 60.

[0057] [Manufacturing of superconducting rectangular wire for superconducting coils] For the superconducting rectangular wire for superconducting coils as described above, the method for coating the fused resin layer includes, but is not limited to, a method in which a varnish made by dissolving a thermoplastic fused resin in a solvent is used and the coating is performed by a resin baking process, and the method for coating the insulating resin layer includes, but is not limited to, a method in which a varnish made by dissolving an insulating resin in a solvent is used and the coating is performed by a resin baking process.

[0058] Another advantage of using the above superconducting rectangular wire is that when it is used to make irregular coils such as saddle-shaped coils in addition to solenoid coils, the superconducting rectangular wires can be brought into local contact with each other during the coil making process and temporarily fixed by heating the contact points, preventing the tension of the winding from loosening and improving the winding workability.

[0059] 3. Manufacturing method of superconducting coil The method for manufacturing a superconducting coil of the present invention includes a winding step of spirally winding the above-mentioned superconducting rectangular wire 10 on the outer peripheral surface of the winding frame 60 along the approximate circumferential direction of the winding frame 60 to form a coil having at least two superconducting rectangular wire layers in which adjacent wires 1 in the axial direction of the winding frame 60 are arranged in parallel while being spaced apart from each other, and a heat treatment step of subjecting the coil formed in the winding step to a heat treatment at a temperature equal to or higher than the glass transition temperature of the amorphous resin (preferably a temperature 30°C higher than the glass transition temperature) and equal to or lower than 300°C when the thermoplastic fusion resin is an amorphous resin, or at a temperature equal to or higher than the melting point of the crystalline resin and equal to or lower than 300°C when the thermoplastic fusion resin is a crystalline resin. By going through such a simple method, a superconducting coil 100 capable of preventing quenching can be manufactured without performing impregnation and hardening treatments using resin. Examples of the amorphous resin include phenoxy resin and polyester resin.

[0060] This manufacturing method will be described below with reference to Fig. 9. In the winding step, the superconducting rectangular wire 10 is spirally wound in at least two layers on the outer circumferential surface of the reel 60 along the approximate circumferential direction of the reel 60 so as to be arranged as shown in Fig. 9(a) when viewed in a cross section including the axis of the reel, to form a coil. Next, in the heat treatment step, the coil is heat-treated at a temperature equal to or higher than the glass transition temperature of the amorphous resin (preferably a temperature 30°C higher than the glass transition temperature) and equal to or lower than 300°C when the thermoplastic fusion resin is an amorphous resin, or at a temperature equal to or higher than the melting point of the crystalline resin and equal to or lower than 300°C when the thermoplastic fusion resin is a crystalline resin, whereby the thermoplastic fusion resins 2-1, 2-2,..., 2-10 melt and fuse to each other to form one fusion resin layer 2' as shown in Fig. 9(b).

[0061] The method for manufacturing a superconducting coil according to the present invention shown in Figs. 5-6 includes a winding step in which the above-mentioned superconducting rectangular wire 10 is spirally wound on the outer peripheral surface of the winding frame 60 along the approximate circumferential direction of the winding frame 60 to form a coil having one superconducting rectangular wire layer in which adjacent wires 1 in the axial direction of the winding frame 60 are arranged in parallel while being spaced apart from each other, and a heat treatment step in which the coil formed in the winding step is subjected to a heat treatment at a temperature equal to or higher than the glass transition temperature of the amorphous resin (preferably a temperature 30°C higher than the glass transition temperature) and equal to or lower than 300°C when the thermoplastic fusion resin is an amorphous resin, or at a temperature equal to or higher than the melting point of the crystalline resin and equal to or lower than 300°C when the thermoplastic fusion resin is a crystalline resin. By going through such a simple method, a superconducting coil 100 capable of preventing quenching can be manufactured without performing impregnation and hardening treatments using resin. Examples of the amorphous resin include phenoxy resin and polyester resin.

[0062] This manufacturing method will be described below with reference to Fig. 10. In the winding step, the superconducting rectangular wire 10 is spirally wound in one layer on the outer circumferential surface of the reel 60 along the approximate circumferential direction of the reel 60 so as to be arranged as shown in Fig. 10(a) when viewed in a cross section including the axis of the reel, to form a coil. Next, in the heat treatment step, the coil is heat-treated at a temperature equal to or higher than the glass transition temperature of the amorphous resin (preferably a temperature 30°C higher than the glass transition temperature) and equal to or lower than 300°C when the thermoplastic fusion resin is an amorphous resin, or at a temperature equal to or higher than the melting point of the crystalline resin and equal to or lower than 300°C when the thermoplastic fusion resin is a crystalline resin, whereby the thermoplastic fusion resins 2-6, 2-7,..., 2-10 melt and fuse to each other to form one fusion resin layer 2' as shown in Fig. 10(b).

[0063] As a method for forming a uniform fusion resin layer, it is preferable to wind the superconducting rectangular wire 10 while applying a constant tension thereto in the winding step.

[0064] In the above heat treatment step, when a phenoxy resin is used as the thermoplastic fusion resin 2, the heating temperature is 100 to 300° C., and preferably 130 to 250° C. If the fusion treatment temperature is less than 100° C., a long fusion treatment time is required, whereas if the fusion treatment temperature exceeds 300° C., the performance of the superconducting wire may be deteriorated due to heating, which is undesirable. EXAMPLES

[0065] Next, in order to further clarify the effects of the present invention, examples and comparative examples will be described, but the present invention is not limited to these examples.

[0066] A NbTi wire with a copper or copper alloy surface coating was coated with a polyamideimide resin (Totoku Paint Co., Ltd., Neoheat AlOOC) as an insulating resin layer, and a phenoxy resin (Nippon Steel Chemical & Material Co., Ltd., YP-50) as a fusion resin layer to produce superconducting rectangular wires of Examples 1 to 6 and Comparative Examples 1 to 6 as shown in FIG. 11 with the dimensions shown in the "Wire", "Insulating Resin Layer", and "Fusion Resin Layer" columns in Table 1 below. This superconducting rectangular wire was wound in 20 layers on a SUS304 reel with a body diameter of 300 mm and a width of 500 mm, and then placed in an argon atmosphere furnace and heated at 200°C for 120 minutes to obtain a superconducting coil. The dimensions of the superconducting coils of Examples 1 to 6 and Comparative Examples 1 to 6 are as shown in Table 1 below.

[0067] The superconducting coils of Examples 1 to 6 and Comparative Examples 1 to 6 were cooled with liquid helium, and current was repeatedly passed (current increase rate 50 A / min.) until the designed magnetic field was achieved. The maximum magnetic field, the number of training quenches required to reach the maximum magnetic field, and the number of heat cycles (room temperature and 4K) required to reduce the magnetic field after the maximum magnetic field was achieved were evaluated. The results are shown in Table 1 below.

[0068] [Table 1]

[0069] For Examples 7 to 8 and Comparative Examples 7 to 8, superconducting coils were manufactured under the same conditions as Examples 1 to 6 and Comparative Examples 1 to 6, except that only one layer of superconducting rectangular wire having the dimensions shown in the "Wire material," "Insulating resin layer," and "Fusion resin layer" columns in Table 2 below was wound around a reel, and evaluations were performed in the same manner as for Examples 1 to 6 and Comparative Examples 1 to 6.

[0070] [Table 2] [Explanation of symbols]

[0071] 1,1' wire rod 1'-1~1'-10, 1a'-1~1a'-10, 1b'-1~1b'-10 Specific parts of wire 10,10' superconducting rectangular wire 100 Superconducting coil 2,2-1~2-10 Fusion resin layer 2', 2a', 2b' Thermoplastic adhesive resin or adhesive resin layer 3a Insulating resin layer 41~47,41b~44b,51,52 void 60 Winding frame 61 Body of reel 61a Outer circumference of the body of the reel 62,63 Flange of reel 71 Inner void 72 Outer void L1,L2,L1b,L2b Superconducting rectangular wire layer S1,S2 Separated part W1 Long side of wire W1': Long side of wire covered with insulating resin W2 Long side of superconducting rectangular wire T1 Short side of wire T1' Short side of wire covered with insulating resin T2 Short side of superconducting rectangular wire R1 Radius of curvature of wire corner R1' Radius of curvature of wire covered with insulating resin R2 Radius of curvature of the corner of the superconducting rectangular wire

Claims

1. A reel; The outer peripheral surface of the reel is coated with copper or a copper alloy. ３ At least two superconducting rectangular wire layers are formed by spirally winding a superconducting rectangular wire containing an Sn-based wire and having a substantially rectangular cross section substantially along the circumferential direction of the reel, so that adjacent wires in the axial direction of the reel are arranged parallel to each other while being spaced apart from each other; A superconducting coil comprising: At least a thermoplastic fusion resin is provided in the gap between adjacent wires in the same superconducting rectangular wire layer and in the gap between adjacent wires located in each of two adjacent superconducting rectangular wire layers, A superconducting coil characterized in that, when viewed in a cross section including the axis of the winding frame, at least one of the voids that can be defined and formed on the outer surfaces of a total of three superconducting flat wire materials located in the two adjacent superconducting flat wire layers and adjacent to each other, and the voids that can be defined and formed on the outer surfaces of a total of four superconducting flat wire materials, has a void ratio (V1), which is the area ratio occupied by the at least two superconducting flat wire layers, of 4% or less.

2. The superconducting coil according to claim 1, characterized in that the gap is located in the two adjacent superconducting rectangular wire layers and is defined by the outer surfaces of a total of three or four superconducting rectangular wires adjacent to each other when viewed in a cross section including the axis of the winding frame.

3. A reel; The outer peripheral surface of the reel is coated with copper or a copper alloy. ３ a superconducting rectangular wire layer formed by winding a superconducting rectangular wire containing an Sn-based wire and having a substantially rectangular cross section in a spiral manner substantially along the circumferential direction of the reel such that adjacent wires in the axial direction of the reel are arranged parallel to each other while being spaced apart from each other; A superconducting coil comprising: At least a thermoplastic fusion resin is provided in the space between adjacent wires in the superconducting rectangular wire layer, A superconducting coil characterized in that, when viewed in a cross section including the axis of the winding frame, the voids that can be formed on the outer surfaces of a total of two adjacent superconducting rectangular wires have a void ratio (V1), which is the area ratio of the superconducting rectangular wire layer, of 4% or less.

4. 4. The superconducting coil according to claim 1, wherein the superconducting rectangular wire has a fusion resin layer made of the thermoplastic fusion resin that covers the outer surface of the wire.

5. 5. The superconducting coil according to claim 1, wherein the thermoplastic fusion resin is made of at least one resin selected from the group consisting of phenoxy resin, polyamide resin and polyester resin.

6. 6. The superconducting coil according to claim 4, wherein the superconducting rectangular wire further comprises an insulating resin layer between an outer peripheral surface of the wire and the fusion resin layer.

7. 7. The superconducting coil according to claim 6, wherein the insulating resin layer is made of at least one resin selected from the group consisting of polyvinyl formal resin, polyamide-imide resin, polyimide resin, polyester resin and polyurethane resin.

8. 8. The superconducting coil according to claim 6, wherein the average coating thickness of the insulating resin layer is 0.005 mm or more and 0.100 mm or less.

9. 9. The superconducting coil according to claim 1, wherein the wire is a rectangular wire, and the radius of curvature (R1) of the corners is 0.1 mm or more and 0.4 mm or less.

10. The superconducting coil according to any one of claims 1 to 9, characterized in that the wire is a rectangular wire, and the radius of curvature (R1) of the corners satisfies the following formulas (1) and (2). [0010]

11. NbTi or Nb with copper or copper alloy surface coating ３ A Sn-based wire, A fusion resin layer made of a thermoplastic fusion resin that covers the outer peripheral surface of the wire. A superconducting rectangular wire for a superconducting coil, comprising: The average coating thickness of the fusion resin layer is 0.005 mm or more and 0.100 mm or less, A superconducting rectangular wire, characterized in that the radius of curvature (R2) of the corners of the superconducting rectangular wire satisfies the following formulas (3) and (4). [0025]

12. 12. The superconducting rectangular wire according to claim 11, wherein the average coating thickness of the fusion resin layer is 0.01 mm or more and 0.07 mm or less.

13. 13. The superconducting rectangular wire according to claim 11, wherein the thermoplastic fusion resin is at least one selected from the group consisting of phenoxy resin, polyamide resin and polyester resin.

14. 14. The superconducting rectangular wire according to claim 10, further comprising an insulating resin layer made of insulating resin between an outer peripheral surface of the wire and the fusion resin layer.

15. 15. The superconducting rectangular wire according to claim 14, wherein the insulating resin is at least one selected from the group consisting of polyvinyl formal resin, polyamide-imide resin, polyimide resin, polyester resin and polyurethane resin.

16. 16. The superconducting rectangular wire according to claim 14, wherein the average coating thickness of the insulating resin layer is 0.005 mm or more and 0.100 mm or less.

17. 17. The superconducting rectangular wire according to claim 11, wherein the wire is a rectangular wire and the radius of curvature (R1) of the corners is 0.1 mm or more and 0.4 mm or less.

18. The superconducting rectangular wire according to any one of claims 11 to 17, characterized in that the wire is a rectangular wire and the radius of curvature (R1) of the corner portion satisfies the following formulas (1) and (2). [0030]

19. A winding process in which the superconducting flat wire according to any one of claims 10 to 18 is spirally wound on an outer peripheral surface of a reel along a substantially circumferential direction of the reel to form a coil having at least two superconducting flat wire layers in which adjacent wires in the axial direction of the reel are arranged in parallel with a space between each other; a heat treatment process for subjecting the coil formed in the winding process to a heat treatment at a temperature of not less than the glass transition temperature of the amorphous resin and not more than 300° C. when the thermoplastic fusion resin is an amorphous resin, or at a temperature of not less than the melting point of the crystalline resin and not more than 300° C. when the thermoplastic fusion resin is a crystalline resin; A method for manufacturing a superconducting coil, comprising:

20. A winding process in which the superconducting flat wire according to any one of claims 10 to 18 is spirally wound on an outer peripheral surface of a reel along a substantially circumferential direction of the reel to form a coil having one layer of superconducting flat wire in which adjacent wires in the axial direction of the reel are arranged in parallel with a space between them; a heat treatment process for subjecting the coil formed in the winding process to a heat treatment at a temperature of not less than the glass transition temperature of the amorphous resin and not more than 300° C. when the thermoplastic fusion resin is an amorphous resin, or at a temperature of not less than the melting point of the crystalline resin and not more than 300° C. when the thermoplastic fusion resin is a crystalline resin; A method for manufacturing a superconducting coil, comprising:

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