Superconducting coil

Abstract

To provide a superconducting coil in which a superconducting characteristic is hardly generated.SOLUTION: A superconducting coil 100 comprises: a winding part 30 to which a superconducting wire rod 10 is wound; and a terminal part 20 that is provided to at least one terminal of the superconducting wire rod 10 constructing the winding part 30. The terminal part 20 includes a pair of connection tapes 21 electrically connecting end region parts 10A and 10B containing one end of the superconducting wire rod 10 and connected parts 25 and 35 that are a connection body or an electrode connected to the other winding part 30. First end parts 23 and 33 of the pair of connection tapes 21 are bonded to both surfaces of the end region parts 10A and 10B while nipping the end region parts 10A and 10B. Second end parts 24 and 34 of the pair of connection tapes 21 are boned to both surfaces of the connected parts 25 and 35 while nipping the connected parts 25 and 35.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a superconducting coil. [Background technology]

[0002] The superconducting coil described in Patent Document 1 is configured by stacking multiple pancake coils. Adjacent pancake coils in the stacking direction are electrically connected to each other at connection parts. The top and bottom pancake coils are provided with electrodes for passing current. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-307917 A Summary of the Invention [Problem to be solved by the invention]

[0004] When a large current is passed through a superconducting coil, an electromagnetic force is applied to the superconducting coil in the radial outward direction, and a tensile force acts on the superconducting wire that constitutes the superconducting coil. This causes bending deformation of the superconducting wire at the connection part between the superconducting wire and the connection part or the electrode, and the characteristics of the superconducting coil may be deteriorated due to the deterioration of the superconducting wire.

[0005] An object of one embodiment of the present invention is to provide a superconducting coil in which deterioration of superconducting characteristics is unlikely to occur. [Means for solving the problem]

[0006] One aspect of the present invention provides a superconducting coil comprising a winding portion around which superconducting wire is wound, and a terminal portion provided on at least one terminal of the superconducting wire constituting the winding portion, wherein the terminal portion has a pair of connection tapes electrically connecting an end region portion including one end of the superconducting wire and a connected portion which is a connector or electrode connected to the other winding portion, and portions of the pair of connection tapes are joined to both sides of the end region portion, sandwiching the end region portion, and other portions of the pair of connection tapes are joined to both sides of the connected portion, sandwiching the connected portion.

[0007] According to this configuration, the pair of connection tapes are joined to both sides, sandwiching the end region and the connected portion, respectively, so that when a tensile force is applied, the tensile load can be borne at the joints on both sides. This makes it possible to reduce stress concentration at the joints. This makes it possible to prevent damage to the superconducting wire and the connection tape due to stress concentration. This makes it possible to suppress deterioration of the superconducting characteristics.

[0008] It is preferable that the terminal portion further includes a spacer inserted between the pair of connection tapes, and that the spacer regulates displacement of the two connection tapes in a direction in which they approach each other.

[0009] The connection tape may be a superconducting wire having the same configuration as the superconducting wire that constitutes the winding portion.

[0010] The connecting tape may be a metal tape.

[0011] The superconducting wire constituting the winding portion comprises a superconducting laminate having a metal substrate and an oxide superconducting layer, and it is preferable that the joint length between the connection tape connected to the surface of the superconducting wire on which the metal substrate is formed and the superconducting wire of the pair of connection tapes is longer than the joint length between the connection tape connected to the surface on which the oxide superconducting layer is formed and the superconducting wire. Effect of the Invention

[0012] According to one aspect of the present invention, it is possible to provide a superconducting coil in which deterioration of superconducting properties is unlikely to occur. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a front view of the superconducting coil according to the embodiment. [Diagram 2] 1 is a cross-sectional view of an oxide superconducting wire used in a superconducting coil of an embodiment. [Diagram 3] 2 is a cross-sectional view of an end portion of a superconducting coil according to an embodiment. FIG. [Figure 4] 2 is a cross-sectional view of an end portion of a superconducting coil according to an embodiment. FIG. [Diagram 5] 1 is a perspective view showing a schematic structure of a superconducting coil according to an embodiment. [Figure 6] FIG. 11 is a cross-sectional view of a first modified example of a terminal portion. [Figure 7] FIG. 11 is a cross-sectional view of a second modified example of a terminal portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings.

[0015] [Superconducting coil] Fig. 1 is a front view of a superconducting coil 100 of an embodiment. Fig. 2 is a cross-sectional view of an oxide superconducting wire 10 used in the superconducting coil 100. Fig. 3 is a cross-sectional view of an outer peripheral terminal portion 20A of the superconducting coil 100. Fig. 4 is a cross-sectional view of an inner peripheral terminal portion 20B of the superconducting coil 100. Fig. 5 is a perspective view showing a schematic structure of the superconducting coil 100.

[0016] As shown in FIG. 1, the superconducting coil 100 includes a plurality of winding portions 30 (see FIG. 5) and terminal portions 20. The winding section 30 is composed of an oxide superconducting wire 10 (superconducting wire). The winding section 30 is a multi-layer wound coil in which the oxide superconducting wire 10 is wound multiple times. "C" is the winding axis of the winding section 30. The winding section 30 is, for example, a circular pancake coil. The direction around the winding axis C is the circumferential direction of the winding section 30. The winding section 30 may be configured such that the oxide superconducting wire 10 and an insulating tape are wound together. The winding section 30 may be impregnated with a resin such as an epoxy resin. The multiple winding portions 30 are stacked in the direction of the winding axis C (see FIG. 5).

[0017] As shown in Fig. 2, the oxide superconducting wire 10 includes a superconducting laminate 5 and a stabilization layer 6. The oxide superconducting wire 10 is a specific example of a "superconducting wire".

[0018] The superconducting laminate 5 includes a metal substrate 1, an intermediate layer 2, an oxide superconducting layer 3, and a protective layer 4. The superconducting laminate 5 has a structure in which the oxide superconducting layer 3 and the protective layer 4 are formed on the metal substrate 1 via the intermediate layer 2. That is, the superconducting laminate 5 has a configuration in which the intermediate layer 2, the oxide superconducting layer 3, and the protective layer 4 are laminated in this order on one surface of the tape-shaped metal substrate 1.

[0019] The oxide superconducting wire 10 is formed in a tape shape. The Y direction is the thickness direction of the oxide superconducting wire 10, and is the direction in which the metal substrate 1, the intermediate layer 2, the oxide superconducting layer 3, and the protective layer 4 are laminated. The X direction is the width direction of the oxide superconducting wire 10, and is a direction perpendicular to the length direction and thickness direction of the oxide superconducting wire 10.

[0020] The metal substrate 1 is made of a metal. Specific examples of the metal constituting the metal substrate 1 include nickel alloys such as Hastelloy (registered trademark); stainless steel; and oriented Ni-W alloys in which a texture is introduced into a nickel alloy. The thickness of the metal substrate 1 may be appropriately adjusted depending on the purpose, and is, for example, in the range of 10 to 500 μm. One surface of the metal substrate 1 (the surface on which the intermediate layer 2 is formed) is referred to as a first main surface 1a, and the surface opposite to the first main surface 1a is referred to as a second main surface 1b.

[0021] The intermediate layer 2 is provided between the metal substrate 1 and the oxide superconducting layer 3. The intermediate layer 2 is formed on the first main surface 1a of the metal substrate 1. The intermediate layer 2 may have a multi-layer structure, and may have, for example, a diffusion prevention layer, a bed layer, an orientation layer, a cap layer, etc., in this order from the metal substrate 1 side to the oxide superconducting layer 3 side. These layers are not necessarily provided one by one, and some layers may be omitted, or two or more layers of the same type may be repeatedly laminated. Note that the intermediate layer 2 is not an essential component of the oxide superconducting wire 10, and if the metal substrate 1 itself has orientation, the intermediate layer 2 may not be formed.

[0022] The diffusion prevention layer has a function of preventing some of the components of the metal substrate 1 from diffusing and being mixed as impurities into the oxide superconducting layer 3. The diffusion prevention layer is made of, for example, Si3N4, Al2O3, GZO (Gd2Zr2O7), etc. The thickness of the diffusion prevention layer is, for example, 10 to 400 nm.

[0023] A bed layer may be formed on the diffusion prevention layer in order to reduce the reaction at the interface between the metal substrate 1 and the oxide superconducting layer 3 and to improve the orientation of the layer formed thereon. Examples of materials for the bed layer include Y2O3, Er2O3, CeO2, Dy2O3, Eu2O3, Ho2O3, and La2O3. The thickness of the bed layer is, for example, 10 to 100 nm.

[0024] The orientation layer is formed from a biaxially oriented material to control the crystal orientation of the cap layer thereon. Examples of materials for the orientation layer include metal oxides such as Gd2Zr2O7, MgO, ZrO2-Y2O3 (YSZ), SrTiO3, CeO2, Y2O3, Al2O3, Gd2O3, Zr2O3, Ho2O3, and Nd2O3. The orientation layer is preferably formed by IBAD (Ion-Beam-Assisted Deposition).

[0025] The cap layer is formed on the surface of the above-mentioned orientation layer and is made of a material that allows crystal grains to self-orient in the in-plane direction. Examples of materials for the cap layer include CeO2, Y2O3, Al2O3, Gd2O3, ZrO2, YSZ, Ho2O3, Nd2O3, and LaMnO3. The thickness of the cap layer is in the range of 50 to 5000 nm.

[0026] The oxide superconducting layer 3 is made of an oxide superconductor. The oxide superconductor is not particularly limited, but for example, the oxide superconductor represented by the general formula REBa2Cu3O X The RE-Ba-Cu-O oxide superconductor (REBCO oxide superconductor) represented by (RE123) can be used. The rare earth element RE can be one or more of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Among them, one of Y, Gd, Eu, and Sm, or a combination of two or more of these elements is preferred. In general, X is 7-x (oxygen deficiency amount x: about 0 to 1). The oxide superconducting layer 3 has a thickness of, for example, about 0.5 to 5 μm. This thickness is preferably uniform in the longitudinal direction. The oxide superconducting layer 3 is formed on the main surface 2a of the intermediate layer 2 (the surface opposite to the metal substrate 1).

[0027] The protective layer 4 has functions such as bypassing an overcurrent that occurs in the event of an accident and suppressing a chemical reaction that occurs between the oxide superconducting layer 3 and a layer provided on the protective layer 4. Examples of materials for the protective layer 4 include silver (Ag), copper (Cu), gold (Au), an alloy of gold and silver, other silver alloys, copper alloys, and gold alloys. The protective layer 4 covers at least the main surface 3a (the surface opposite to the intermediate layer 2) of the oxide superconducting layer 3. The thickness of the protective layer 4 is not particularly limited, but may be, for example, about 1 to 30 μm.

[0028] Reference numeral 5a denotes a first main surface of the superconducting laminate 5 (main surface 4a of protective layer 4). The first main surface 5a is the surface of the superconducting laminate 5 on which the oxide superconducting layer 3 is formed. Reference numeral 5b denotes a side surface of the superconducting laminate 5 (the side surface of the metal substrate 1, the side surface of the intermediate layer 2, the side surface of the oxide superconducting layer 3, and the side surface of the protective layer 4). Reference numeral 5c denotes a second main surface of the superconducting laminate 5 (second main surface 1b of the metal substrate 1), which is the surface opposite to the first main surface 5a. The second main surface 5c is the surface of the superconducting laminate 5 on which the metal substrate 1 is formed.

[0029] The stabilization layer 6 covers the first main surface 5a, the side surfaces 5b, 5b and the second main surface 5c of the superconducting laminate 5. The stabilization layer 6 is formed to surround the superconducting laminate 5. The stabilization layer 6 functions as a bypass section that diverts an overcurrent that is generated when the oxide superconducting layer 3 transitions to a normal conducting state. Examples of materials constituting the stabilization layer 6 include metals such as copper, copper alloys (e.g., Cu-Zn alloys, Cu-Ni alloys, etc.), aluminum, aluminum alloys, silver, etc. The thickness of the stabilization layer 6 is, for example, about 10 to 300 μm. The stabilization layer 6 can be formed by plating (e.g., electrolytic plating).

[0030] In winding portion 30 (see FIG. 1), oxide superconducting wire 10 is desirably wound with metal substrate 1 facing the outer periphery and oxide superconducting layer 3 facing the inner periphery.

[0031] 1, the terminal portion 20 is provided at one end and the other end of the winding portion 30. The terminal portion 20 provided at the terminal on the outer periphery of the winding portion 30 is also referred to as the outer periphery terminal portion 20A. The terminal portion 20 provided at the terminal on the inner periphery of the winding portion 30 is also referred to as the inner periphery terminal portion 20B. Outer peripheral terminal portion 20A includes two connection tapes 21 (a pair of connection tapes 21) and a spacer 22. Connection tape 21 is a superconducting wire having the same configuration as oxide superconducting wire 10, for example.

[0032] At a first end 23 (one end) of the outer peripheral terminal portion 20A, the two connection tapes 21 sandwich the end region 10A including the outer peripheral end 10a of the oxide superconducting wire 10. The two connection tapes 21 are bonded to one and the other surfaces of the end region 10A, respectively, and are electrically connected to the end region 10A.

[0033] At the second end 24 (the other end) of the outer peripheral terminal portion 20A, the two connection tapes 21 sandwich a sheet-like connected portion 25. The connected portion 25 is a connector or an electrode connected to another winding portion 30. The connected portion 25 is formed of a conductor such as a metal. The two connection tapes 21 are respectively joined to one and the other surface of the connected portion 25 and are electrically connected to the connected portion 25.

[0034] As shown in Figure 3, of the two connection tapes 21, the first connection tape 21A is joined to the end region 10A and the connected portion 25 with the surface 21Aa on the side on which the oxide superconducting layer 3 is provided facing the surface 10Aa of the end region 10A on the side on which the oxide superconducting layer 3 is provided. Of the two connection tapes 21, the second connection tape 21B is joined to the end region 10A and the connected portion 25 with the surface 21Ba on the side on which the oxide superconducting layer 3 is provided facing the surface 10Ab of the end region 10A on which the metal substrate 1 is provided. The connecting tape 21 is joined to the end region 10A and the connected portion 25 by a bonding material 26 such as solder.

[0035] The two connection tapes 21 are preferably made of superconducting wires having the same configuration. If the two connection tapes 21 have the same configuration, their mechanical strengths will be equal. This allows the two connection tapes 21 to equally share the tensile load at the joints with the end region 10A and the connected portion 25, thereby suppressing stress concentration.

[0036] The two connection tapes 21 are connected to the end region 10A of the oxide superconducting wire 10 and the connected portion 25, and thus relay the connection between the end region 10A of the oxide superconducting wire 10 and the connected portion 25. Therefore, the end region 10A of the oxide superconducting wire 10 and the connected portion 25 are electrically connected.

[0037] 1, the spacer 22 is in the form of a plate whose thickness decreases from one end 22a to the other end 22b. The spacer 22 is made of a resin material such as fiber reinforced resin (glass fiber reinforced resin, carbon fiber reinforced resin, etc.).

[0038] The spacer 22 is inserted between the two connecting tapes 21, close to the connected portion 25. One end 22a of the spacer 22 is positioned opposite one end of the connected portion 25. Therefore, the thickness of the spacer 22 decreases as it moves away from the connected portion 25. The thickness of the spacer 22 at one end 22a is equal to or less than the thickness of the connected portion 25. Since the spacer 22 is located between the two connecting tapes 21, it restricts the displacement of the two connecting tapes 21 in the direction in which they approach each other. This makes it possible to suppress bending deformation of the connecting tape 21 at one end of the connected portion 25. This makes it possible to avoid damage to the connecting tape 21.

[0039] The inner peripheral terminal portion 20B includes two connection tapes 21 and a spacer 22. At a first end 33 (one end) of the inner peripheral terminal portion 20B, the two connection tapes 21 sandwich the end region 10B including the inner peripheral end 10b of the oxide superconducting wire 10. The two connection tapes 21 are bonded to one and the other surfaces of the end region 10B, respectively, and are electrically connected to the end region 10B.

[0040] At the second end 34 (the other end) of the inner peripheral terminal portion 20B, the two connection tapes 21 sandwich a sheet-like connected portion 35. The connected portion 35 is a connector or an electrode connected to another winding portion 30. The connected portion 35 is formed of a conductor such as a metal. The two connection tapes 21 are respectively joined to one and the other surface of the connected portion 35 and are electrically connected to the connected portion 35.

[0041] As shown in Figure 4, of the two connection tapes 21, the first connection tape 21A is joined to the end region portion 10B and the connected portion 35 with the surface 21Aa on the side on which the oxide superconducting layer 3 is provided facing the surface 10Ba of the end region portion 10B on which the oxide superconducting layer 3 is provided. Of the two connection tapes 21, the second connection tape 21B is joined to the end region 10B and the connected portion 35 with the surface 21Ba on the side on which the oxide superconducting layer 3 is provided facing the surface 10Bb of the end region 10B on which the metal substrate 1 is provided. The connecting tape 21 is joined to the end region 10B and the connected portion 35 by a bonding material 26 such as solder.

[0042] The two connection tapes 21 are connected to the end region 10B of the oxide superconducting wire 10 and the connected portion 35, and thus relay the connection between the end region 10B of the oxide superconducting wire 10 and the connected portion 35. Therefore, the end region 10B of the oxide superconducting wire 10 and the connected portion 35 are electrically connected.

[0043] 1, the spacer 22 is inserted between the two connection tapes 21, close to the connected portion 35. One end 22a of the spacer 22 is positioned opposite one end of the connected portion 35. Therefore, the thickness of the spacer 22 decreases as it moves away from the connected portion 35. The thickness of the spacer 22 at one end 22a is equal to or less than the thickness of the connected portion 35.

[0044] Since the spacer 22 is located between the two connecting tapes 21, it restricts the displacement of the two connecting tapes 21 in the direction in which they approach each other. This makes it possible to suppress bending deformation of the connecting tape 21 at one end of the connected portion 35. This makes it possible to avoid damage to the connecting tape 21.

[0045] When the connected parts 25, 35 are connectors connected to another winding part 30, the oxide superconducting wire 10 is connected to the other winding part 30 (for example, the winding part 30 adjacent in the stacking direction in FIG. 5) via the connection tape 21 and the connected parts 25, 35. When the connected parts 25, 35 are electrodes, the oxide superconducting wire 10 can pass electricity through the electrodes.

[0046] [Effects of the superconducting coil according to the embodiment] When a large current is passed through the superconducting coil 100, an electromagnetic force is applied to the superconducting coil 100 in the radially outward direction, and a tensile force may act on the oxide superconducting wire 10. The superconducting coil 100 includes a terminal portion 20 (20A, 20B) having two connection tapes 21. The two connection tapes 21 are joined to both sides, sandwiching the end region portions 10A, 10B and the connected portions 25, 35, respectively, so that when a tensile force is applied, the tensile load can be borne at the joints on both sides. This makes it possible to alleviate stress concentration at the joints. This makes it possible to prevent the oxide superconducting wire 10 and the connection tapes 21 from being damaged by stress concentration. This makes it possible to suppress deterioration of the superconducting characteristics.

[0047] Since the connection tape 21 is a superconducting wire, the electrical resistance between the end regions 10A, 10B and the connected portions 25, 35 can be reduced, and the electrical characteristics of the terminal portion 20 can be improved.

[0048] FIG. 6 is a cross-sectional view of a terminal portion 20C which is a first modified example of the terminal portion 20. As shown in FIG. As shown in Fig. 6, the terminal portion 20C differs from the terminal portion 20 shown in Fig. 3 in that the connection tape 31 is formed of a metal tape. The connection tape 31 is formed of a metal such as copper or a copper alloy (such as brass). Since the connection tape 31 of the terminal portion 20C is made of a metal tape, the mechanical strength of the terminal portion 20C can be increased.

[0049] FIG. 7 is a cross-sectional view of a terminal portion 120 which is a second modified example of the terminal portion 20. As shown in FIG. 7, the terminal portion 120 includes two connection tapes 121 (121A, 121B). Of the two connection tapes 121, the first connection tape 121A is joined to the upper surface of the end region portion 10A in FIG. Of the two connection tapes 121, the second connection tape 121B is joined to the lower surface of the end region 10A in FIG.

[0050] The second connection tape 121B is longer than the first connection tape 121A. The joint length between the second connection tape 121B and the superconducting wire 10 is longer than the joint length between the first connection tape 121A and the superconducting wire 10. Therefore, the joint area of ​​the second connection tape 121B to the end region 10A is larger than the joint area of ​​the first connection tape 121A to the end region 10A. Since the joint area to the lower surface (surface 10Ab on the side where the metal substrate 1 is provided) of the end region 10A is larger, when a tensile load is applied, stress is more likely to concentrate on the lower surface (surface 10Ab on the side where the metal substrate 1 is provided) of the end region 10A than on the upper surface (surface 10Aa on the side where the oxide superconducting layer 3 is provided) of the end region 10A. Therefore, deterioration of the oxide superconducting layer 3 formed on the side close to the upper surface of the end region 10A of the oxide superconducting wire 10 can be suppressed.

[0051] While the present invention has been described above based on the preferred embodiment, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention. For example, in the terminal portion 20 shown in Fig. 3, a metal material such as solder may be filled between the two connection tapes 21. This increases the mechanical strength of the terminal portion 20 and reduces the electrical resistance in the terminal portion 20. A non-conductive material such as resin may be filled between the two connection tapes 21. This increases the mechanical strength of the terminal portion 20.

[0052] 1 is provided at one and the other ends of the oxide superconducting wire 10 constituting the winding portion 30, the terminal portion may be provided at only one end of the superconducting wire constituting the winding portion. In other words, it is sufficient that the terminal portion is provided at at least one end of the superconducting wire constituting the winding portion. The structure of the superconducting laminate is not limited to the structure shown in Fig. 2. The superconducting laminate does not need to have a protective layer. The superconducting laminate may include layers other than the metal substrate, the intermediate layer, the oxide superconducting layer, and the protective layer. [Explanation of symbols]

[0053] 1...metal substrate, 3...oxide superconducting layer, 5...superconducting laminate, 10...oxide superconducting wire (superconducting wire), 10A, 10B...end region portion, 20, 20C, 120...terminal portion, 20A...outer peripheral terminal portion, 20B...inner peripheral terminal portion, 25, 35...connected portion, 21, 121...connecting tape, 22...spacer, 30...winding portion, 100...superconducting coil.

Claims

1. a winding portion in which a superconducting wire is wound, and a terminal portion provided at at least one terminal of the superconducting wire constituting the winding portion, the terminal portion has a pair of connection tapes that electrically connect an end region portion including one end of the superconducting wire to a connected portion which is a connector or an electrode connected to the other winding portion, The pair of connecting tapes are joined to both sides of the end region with the end region therebetween, the other parts of the pair of connection tapes are joined to both surfaces of the connected part, sandwiching the connected part therebetween; Superconducting coil.

2. The terminal portion further includes a spacer inserted between the pair of connection tapes, 2. The superconducting coil according to claim 1, wherein said spacer regulates displacement of said two connecting tapes in a direction in which they approach each other.

3. 3. The superconducting coil according to claim 1, wherein the connection tape is a superconducting wire having the same configuration as the superconducting wire constituting the winding portion.

4. 3. The superconducting coil according to claim 1, wherein the connection tape is a metal tape.

5. The superconducting wire constituting the winding portion is The superconducting laminate has a metal substrate and an oxide superconducting layer, A superconducting coil as described in any one of claims 1 to 3, wherein the joint length between the connection tape connected to the surface of the superconducting wire on which the metal substrate is formed and the superconducting wire, of a pair of connection tapes, is longer than the joint length between the connection tape connected to the surface on which the oxide superconducting layer is formed and the superconducting wire.

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