JP2021039978A - High-temperature superconducting coil - Google Patents

Abstract

To provide a high-temperature superconducting coil in which deterioration resistance of a thin-film tape wire by installation of a metal plate at the circumference of the coil is improved.SOLUTION: A high-temperature superconducting coil 10 where multiple coils 1 of different diameters, formed by winding a thin-film superconducting tape wire 2 composed of a laminate including at least a high-temperature superconducting layer, are placed in the radial direction is equipped with a strengthening wire 3 of a flexible conductor pasted to at least any one of the outside surface of outermost periphery of an n-th coil 1a (n is a natural number of 1 or more) from the inside or the inside surface of the innermost periphery of an (n+1)th coil 1b, and a flexible metal plate 4 is where the outermost periphery of the n-th coil 1a from the inside and the innermost periphery of the (n+1)th coil 1b are erected on the strengthening wire 3.SELECTED DRAWING: Figure 1

Description

An embodiment of the present invention relates to a high-temperature superconducting coil using a high-temperature superconducting wire composed of laminated thin layers and formed into a tape shape.

In recent years, a (RE) Ba2Cu3Oz system containing rare earths (REs) (where z = 6.2-7, where RE is at least one selected from Y, Nd, Sm, Eu, Gd and Ho). Research on high-temperature superconducting coils using high-temperature superconducting wires typified by REBCO wires using (indicating elements of more than one species) has been actively conducted. In particular, a high-temperature superconducting wire produced by forming a plurality of types of layers on a substrate having a thickness of about 100 μm has a characteristic of having a large current capacity under a high magnetic field. Therefore, it is expected to realize a high-temperature superconducting coil having a high current density and a high allowable stress required to generate a high magnetic field.

Practical methods for forming high-temperature superconducting coils can be roughly classified into several methods depending on the method of winding the high-temperature superconducting wire.

As a typical example of these forming methods, a plurality of pancake coils having different diameters in which high-temperature superconducting wires are wound concentrically are arranged in the same plane, and one coil having a small diameter is a coil having a large diameter. A metal plate is erected between the outer circumference of the coil having a small diameter and the inner circumference of the coil having a large diameter, and is electrically connected.

All the pancake coils connected by this metal plate form one path through which the superconducting current flows.

The high-temperature superconducting wire is also characterized in that the superconducting characteristics are not lost even when a high external force is applied in the longitudinal direction of the high-temperature superconducting wire. On the other hand, this high-temperature superconducting wire is vulnerable to the external force applied in the stacking direction of the plurality of layers described above, and the superconducting characteristics are easily deteriorated by a minute external force.

For example, when a bending stress is locally applied to a high-temperature superconducting wire, the layer is easily peeled off or the layer is broken, and the superconducting characteristics are deteriorated.

Conventionally, a device has been devised to prevent the high-temperature superconducting wire from being unnecessarily distorted by fixing an electrode connected to the starting end of the high-temperature superconducting wire to a winding frame.

Japanese Unexamined Patent Publication No. 2010-98267 Japanese Unexamined Patent Publication No. 2016-163026

However, when a metal plate is erected on a high-temperature superconducting wire between a plurality of coils arranged in the radial direction, there is a problem that the high-temperature superconducting wire around the periphery of the metal plate deteriorates.

The stress applied to the high-temperature superconducting wire becomes discontinuous at the peripheral edge of the metal plate, which is the boundary between the portion where the metal plate is joined and the portion where the metal plate is not joined. In this case, the stress is concentrated around the peripheral edge of the high-temperature superconducting wire due to slight deformation in the vicinity of the peripheral edge.

As described above, the high-temperature superconducting wire is vulnerable to stress in the layer stacking direction, and this stress may cause peeling or breakage of the layer of the high-temperature superconducting wire. In other words, when a metal plate is erected on the high-temperature superconducting wire, the high-temperature superconducting wire around the periphery of the metal plate may deteriorate due to thermal stress when soldering the metal plate or stress concentration during cooling. .. Such deterioration becomes remarkable especially when the stabilizing layer bonded to the uppermost layer or the lowermost layer of the laminated body is thinly formed.

The present invention has been made in consideration of such circumstances, and at least a high temperature in which a plurality of coils having different diameters formed by winding a high temperature superconducting wire composed of a laminated body including a high temperature superconducting layer are arranged in the radial direction. It is an object of the present invention to provide a high-temperature superconducting coil having improved deterioration resistance performance of a high-temperature superconducting wire due to erection of a metal plate on the periphery of the coil.

The high-temperature superconducting coil according to the present embodiment is a high-temperature superconducting coil in which a plurality of coils having different diameters formed by winding a high-temperature superconducting wire composed of a laminated body including at least a high-temperature superconducting layer are arranged in the radial direction from the inside. Reinforcement of a flexible conductor that is attached to at least one of the outermost outer surface of the nth coil (where n is a natural number of 1 or more) or the innermost inner surface of the n + 1th coil. It is characterized by comprising a wire rod and a flexible metal plate in which the outermost outer circumference of the nth coil from the inside and the innermost circumference of the n + 1st coil are erected on the reinforcing wire rod.

The embodiment of the present invention has been made to solve the above-mentioned problems, and at least coils having different diameters formed by winding a high-temperature superconducting wire composed of a laminated body including a high-temperature superconducting layer are arranged in the radial direction. It is an object of the present invention to provide a high-temperature superconducting coil having a plurality of arranged high-temperature superconducting coils having improved deterioration resistance performance of the high-temperature superconducting wire due to the erection of a metal plate on the peripheral edge of the coil.

The perspective view of the high temperature superconducting coil which shows 1st Embodiment. FIG. 3 is an enlarged plan view of a main part showing a connection portion between pancake coils in the superconducting coil according to the first embodiment. FIG. 3 is an enlarged plan view of a main part showing a connection portion between pancake coils in the superconducting coil according to the second embodiment. FIG. 3 is an enlarged plan view of a main part showing a connection portion between pancake coils in a superconducting coil according to a modified example of the second embodiment. FIG. 3 is an enlarged plan view of a main part showing a connection portion between pancake coils in a superconducting coil according to a second modification of the second embodiment. FIG. 3 is an enlarged plan view of a main part showing a connection portion between pancake coils in the superconducting coil according to the third embodiment. The perspective view of the high temperature superconducting coil which shows 4th Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(First Embodiment)

FIG. 1 is a perspective view of a high-temperature superconducting coil showing pancake coils having different sizes connected in the radial direction in the same plane according to the first embodiment.

As shown in FIG. 1, the high-temperature superconducting coil 10 according to the first embodiment is a pancake composed of a high-temperature superconducting wire 2 which is a laminated body including a substrate, which is wound around two winding frames 9 having different diameters and laminated. Coil 1 (1a, 1b) is arranged in the same plane, and one pancake coil with a small diameter (the nth pancake coil from the inside (where n is a natural number of 1 or more)) 1a has a large other diameter. The winding frame 9 is located inside the pancake coil (n + 1st pancake coil) 1b, and is located between the outermost circumference of the pancake coil 1a having a small diameter and the innermost circumference of the pancake coil 1b having a large diameter. It is electrically connected by a metal plate 4 via a reinforcing wire 3 of a flexible conductor from a conductor portion 6 arranged in a part of the pancake.

Then, an adhesive is arranged in the gap between the facing surfaces of the high-temperature superconducting wires 2 that are wound and face each other, and this adhesive is at least one selected from the group consisting of fluororesin tape, paraffin, grease, and silicon oil. It is formed and a release layer is formed, and a release process is performed to suppress the adhesive force of the high-temperature superconducting wire 2 to the facing surface.

The reinforcing wire 3 is configured to have a thinner radial thickness of the pancake coil 1 than the metal plate 4, and the pancake coil 1 is composed of a reduction ratio of superconducting characteristics with respect to a peeling stress applied in the laminating direction of the laminated body. It may be a high-temperature superconducting wire that is lower than the high-temperature superconducting wire 2. The high-temperature superconducting wire may be composed of a bismuth-based superconducting wire. Further, the layers at both ends of the laminated body (the ends in the direction perpendicular to the laminating direction of the laminated body) constituting the pancake coil 1 are stabilizing layers composed of ordinary conductors, and are stable at both ends of the laminated body. The chemical layers are electrically connected to each other.

FIG. 2 is an enlarged plan view of a main part showing a connection portion between the pancake coil 1a and the pancake coil 1b in the high-temperature superconducting coil 10 according to the first embodiment.

The metal plate 4 has a shape in which a large curvature portion 4a and a small curvature portion 4b are combined, whereby the metal plate 4 has flexibility with respect to the connection direction between the superconducting coils 10. Further, a high-temperature superconducting wire 5 is attached along the surface of the large curvature portion 4a of the metal plate 4.

When the high-temperature superconducting coil 10 is cooled, a force in the peeling direction acts on the high-temperature superconducting wire 2 on the surface of the pancake coil 1a due to heat shrinkage, which causes deterioration of the superconducting characteristics. However, since the metal plate 4 is flexible with respect to the connection direction between the pancake coils 1, the superconducting characteristics of the high-temperature superconducting wire 2 in the pancake coil 1 are deteriorated by relaxing the force in the peeling direction. Can be prevented.

Further, the end side of the reinforcing wire 3 is provided with a thin taper toward the end in the radial direction of the pancake coil 1. This taper is formed by laminating a plurality of reinforcing wires 3 having a maximum surface area of the reinforcing wires 3 in contact with the outer surface.

Further, the end side of the reinforcing wire 3 may have a gradient with respect to the winding axis direction of the pancake coil 1, and the length of the pancake coil 1 of the reinforcing wire 3 in the circumferential direction is the metal plate 4. It may be set longer than the length in the circumferential direction of. Furthermore, the reinforcing wire 3 is provided on the side surface of the high-temperature superconducting wire 2 opposite to the high-temperature superconducting layer with respect to the substrate.

This is because the force in the peeling direction can be further relaxed by gradually transmitting the force in the peeling direction to the high-temperature superconducting wire 2 on the outermost surface of the pancake coil 1a having a small diameter.

Further, in order for the metal plate 4 to have flexibility, it is necessary to set the cross-sectional area of the metal plate 4 to be small. Since the electrical resistance increases as the cross-sectional area of the metal plate 4 decreases, the amount of heat generated increases when the pancake coil 1a and the pancake coil 1b are connected and energized using only the metal plate 4, and depending on the amount of heat generated, the temperature rises. The superconducting state of the pancake coil 1 may not be maintained. However, in the present embodiment, since the high-temperature superconducting wire 5 is attached to the surface of the metal plate 4, electricity can be diverted to the high-temperature superconducting wire 5 to reduce the electric resistance.

Further, at least one of the reinforcing wire rod 3 and the metal plate 4 described above is configured by being selected from at least one material of indium, copper, silver, gold, aluminum and an aluminum alloy in order to keep flexibility and electrical resistance low. , The reinforcing wire 3 and the metal plate 4 may be integrally formed.

From the above, by using the method of the present embodiment, the electric resistance at the connection portion between the pancake coil 1a and the pancake coil 1b is suppressed to a low level, and the connection portion has flexibility, so that the high temperature superconducting wire is thermally shrunk. By relaxing the peeling force generated on the surface of the pancake coil 1, it is possible to achieve both the two effects of preventing the deterioration of the superconducting characteristics of the high-temperature superconducting wire 2 in the pancake coil 1.

In this embodiment, the pancake coils 1 (1a, 1b) are arranged in the same plane, but if the inner and outer pancake coils have a step and do not overlap when viewed from the upper surface. The same effect can be obtained even if the metal plate 4 according to this embodiment is used as if it is in the same plane.

(Second Embodiment)

3 to 5 are enlarged plan views of main parts showing the connection portion between the pancake coil 1a and the pancake coil 1b in the high-temperature superconducting coil 10 according to the second embodiment, respectively. In FIGS. 3 to 5, the same parts as those in FIG. 2 are designated by the same reference numerals, and the description of the configuration will be omitted.

In the first embodiment, as shown in FIG. 2, the case where the metal plate 4 has a shape in which a large curvature portion 4a and a small curvature portion 4b are combined is shown, but in the second embodiment, as shown in FIG. A metal plate 7 having a shape in which a curved portion 7a and a straight portion 7b are combined may be formed, and the high-temperature superconducting wire 5 may be attached along the surface of the straight portion 7b.

Further, as a modification of the second embodiment, as shown in FIG. 4, the shape of the flexible portion in which the curved portion 7a and the straight portion 7b are combined is increased to form the metal plate 7, and the surface of the straight portion 7b is formed. The high-temperature superconducting wire 5 may be attached along the line.

Further, as a second modification of the second embodiment, as shown in FIG. 5, a metal plate 8 having a shape in which a bent portion 8a and a straight portion 8b are combined is formed, and a high-temperature superconducting wire 5 is formed on the surface of the straight portion 8b. May be pasted together.

With the above configuration, the same actions and effects as those of the first embodiment can be obtained in the second embodiment of the present invention.

(Third Embodiment)

FIG. 6 is an enlarged plan view of a main part showing a connection portion between pancake coils in the superconducting coil according to the third embodiment. In FIG. 6, the same configurations as those in FIG. 2 are designated by the same reference numerals, and the description of the configurations will be omitted.

In the first embodiment, as shown in FIG. 2, a case where the high-temperature superconducting wire 5 is attached along both sides of the surface of the metal plate 4 is shown, but in the third embodiment, the relationship between the materials of the connecting portion is shown. For example, when the electric resistance is low and the rising temperature is low, the high-temperature superconducting wire 5 may be attached along one side of the surface of the metal plate 4 as shown in FIG.

With the above configuration, the same actions and effects as those of the first embodiment can be obtained in the third embodiment of the present invention.

(Fourth Embodiment)

FIG. 7 is a perspective view of a high-temperature superconducting coil showing coils having different sizes connected in the radial direction in the same plane according to the fourth embodiment.

As shown in FIG. 1, the high-temperature superconducting coil 11 according to the fourth embodiment has a coil 12 (12a, 12b) composed of high-temperature superconducting wires 2 wound around two winding frames 9 having different diameters in the same plane. One coil with a small diameter (nth coil from the inside (where n is a natural number of 1 or more)) 12a is located inside another coil with a large diameter (n + 1th coil) 12b. Between the outermost circumference of the coil 12a having a small diameter and the innermost circumference of the coil 12b having a large diameter, a reinforcing wire rod 3 for a flexible conductor is provided from a conductor portion 6 arranged in a part of the winding frame 9. It is electrically connected by a metal plate 4 via the metal plate 4.

The coil 12 constituting the superconducting coil 11 is not limited to the racetrack shape shown in FIG. 7, and may be applied to a coil including a saddle shape and a two-dimensional or three-dimensional shape in which a plurality of curves or straight lines are combined.

Therefore, also in the fourth embodiment of the present invention, the configurations of the first to third embodiments can be applied to the coils other than the pancake coil, and the same actions and effects as those of the first embodiment can be obtained.

In addition, although the example in which the coils are arranged in the same plane in the above embodiment is shown, if the inner and outer coils have a step and do not overlap when viewed from the upper surface, they are regarded as in the same plane and in this embodiment. The same effect can be obtained by using such a metal plate 4.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the gist of the invention.

These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.

1 (1a, 1b) ... Pancake coil, 2 ... High-temperature superconducting wire, 3 ... Reinforcing wire, 4 (4a, 4b) ... Metal plate, 5 ... High-temperature superconducting wire, 6 ... Conductor, 7 (7a, 7b) ... metal plate, 8 (8a, 8b) ... metal plate, 9 ... winding frame, 10 ... high-temperature superconducting coil, 11 ... high-temperature superconducting coil, 12 (12a, 12b) ... coil.

Claims (17)

In a high-temperature superconducting coil in which a plurality of coils having different diameters formed by winding a high-temperature superconducting wire composed of a laminate including at least a high-temperature superconducting layer are arranged in the radial direction.
A flexible conductor that is attached to at least one of the outermost outer surface of the nth coil (where n is a natural number of 1 or more) or the innermost inner surface of the n + 1th coil from the inside. Reinforcing wire and
A high-temperature superconducting coil comprising: a flexible metal plate in which the outermost circumference of the nth coil from the inside and the innermost circumference of the n + 1st coil are erected on a reinforcing wire rod. The metal plate has a shape in which a curved portion and a straight portion are combined, a shape in which a large curved portion and a small curved portion are combined, a shape in which a bent portion and a straight portion are combined, or a bent portion and a small curved portion. The high-temperature superconducting coil according to claim 1, wherein the high-temperature superconducting coil has a combined shape. The high temperature according to claim 1 or 2, wherein a high-temperature superconducting wire is bonded to the metal plate along one or both sides of the surface of a straight portion or a small curved portion of the metal plate. Superconducting coil. From claim 1, the coil shape is a coil including a pancake coil shape, a racetrack shape, a saddle shape, and a two-dimensional or three-dimensional shape in which a plurality of curves or straight lines are combined. The high-temperature superconducting coil according to any one of claims 3. The high-temperature superconducting coil according to any one of claims 1 to 4, wherein a taper is provided on the end side of the reinforcing wire in the radial direction of the coil. The high-temperature superconducting coil according to claim 5, wherein the taper is formed by laminating a plurality of the reinforcing wires having the reinforcing wire having the maximum surface area in contact with the outer surface. The high-temperature superconducting coil according to any one of claims 1 to 6, wherein the end side of the reinforcing wire has a narrow gradient toward the end in the winding axis direction of the coil. The high-temperature superconducting coil according to any one of claims 1 to 7, wherein the length of the reinforcing wire in the circumferential direction of the coil is longer than the length of the metal plate in the circumferential direction. The method according to any one of claims 1 to 8, wherein the reinforcing wire is a high-temperature superconducting wire having a lower ratio of reduction in superconducting characteristics with respect to a peeling stress applied in the laminating direction of the laminated body as compared with the high-temperature superconducting wire. High-temperature superconducting coil. The high-temperature superconducting coil according to claim 9, wherein the high-temperature superconducting wire is a bismuth-based superconducting wire. The high temperature according to any one of claims 1 to 8, wherein at least one of the reinforcing wire rod and the material of the metal plate is selected from at least one of indium, copper, silver, gold, aluminum and an aluminum alloy. Superconducting coil. The high-temperature superconducting coil according to any one of claims 1 to 11, wherein the reinforcing wire is thinner in the radial direction of the coil than the metal plate. The laminate includes a substrate as a layer and
The high-temperature superconducting coil according to any one of claims 1 to 12, wherein the reinforcing wire is provided on the side surface of the high-temperature superconducting wire opposite to the high-temperature superconducting layer with respect to the substrate. Claim 1 according to claim 1, wherein an adhesive is arranged in a gap between the facing surfaces of the high-temperature superconducting wires that are wound and face each other, and the adhesive is subjected to a mold release process that suppresses the adhesive force to the facing surfaces. Item 3. The high-temperature superconducting coil according to any one of Item 13. The high-temperature superconducting coil according to claim 14, wherein the mold release treatment is performed by forming a mold release layer composed of at least one selected from the group consisting of fluororesin tape, paraffin, grease, and silicone oil. The layers at both ends of the laminate are stabilizing layers composed of ordinary electric conductors, and the stabilizing layers at both ends are electrically connected to each other, any one of claims 1 to 15. The high-temperature superconducting coil described in the section. The high-temperature superconducting coil according to any one of claims 1 to 16, wherein the metal plate and the reinforcing wire are integrally formed.

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