Superconducting wire, superconducting wire manufacturing method, superconducting coil, and coil device

Abstract

To simplify the application of a release material to a superconducting wire, and configure a superconducting coil to have a high strength without deterioration in thermal conductivity.SOLUTION: A superconducting wire 3 is a tape-shaped wire 3 having a superconducting layer 12 laminated together with other layers on a metal substrate 14, and a release material 5 is applied to a portion of the surface of the wire 3, which reduces the adhesive strength with adhesive materials more than other portions. When viewed in cross section of the wire 3, coated areas 21 where the release material 5 is applied to one or more wide sides and uncoated areas 22 where the release material 5 is not applied to all sides are alternately arranged at least once in the longitudinal direction of the wire 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to superconductivity technology. [Background technology]

[0002] Second generation REBCO (REBa2Cu3Oy 7-δ ) high-temperature superconducting wire. This high-temperature superconducting wire is constructed by sequentially forming an intermediate layer, which provides crystalline orientation, on a tape-shaped metal substrate that provides strength, and then a superconducting layer on top of that. Furthermore, a protective layer (first metal layer) is required to surround the superconducting layer to prevent deterioration of the superconducting layer due to air. Silver (Ag) is typically used as the material for the first metal layer. Because silver is expensive, the first metal layer is kept to the minimum necessary thickness (approximately a few micrometers) to prevent deterioration. Furthermore, a stabilizing layer (second metal layer) is configured to cover the protective layer (first metal layer) to prevent burnout due to the bypass current during quenching of the superconducting layer. The type and thickness of the second metal layer are selected to provide electrical resistance that prevents burnout when the quench current bypasses it. Copper (Cu) is typically used as the material. This copper is tightly applied to cover the first metal layer with a thickness of several micrometers to several tens of micrometers. Although current REBCO wires have a certain degree of mechanical strength due to the tensile strength of the metal substrate, when stress acts in a direction that causes the layers to peel off, peeling occurs near the superconducting layer, and the superconducting properties tend to deteriorate. Therefore, when constructing a coil, measures to prevent this peeling are required.

[0003] High-temperature superconducting coils are made by winding REBCO wire in a pancake shape and fixing it into a coil with an adhesive material. This high-temperature superconducting coil is prone to deterioration when cooled because thermal stress during cooling acts in a direction that causes the superconducting layer of the REBCO wire to peel off. For this reason, various countermeasures have been taken.

[0004] For example, when a superconducting coil is formed into a coil shape and fixed with an adhesive material, a weak interface is created in advance that peels off under a stress weaker than the peeling stress of the superconducting layer. One example is a method in which a release treatment is applied to the surface of a tape-shaped insulating wire that is overlapped and co-wound with the superconducting wire (see Figure 3). The release treatment on the surface of this co-wound insulating wire causes peeling between the adhesive used to fix the coil. This peeling reduces the thermal stress applied to the superconducting layer. Furthermore, by applying a release material to the surface of the superconducting wire (see Figures 7 and 9), when the superconducting wire is wound into a coil (see Figures 8 and 10), a peeling area is formed similarly to the above, reducing the thermal stress in the superconducting layer and preventing degradation. In addition to these methods, other methods for preventing peeling degradation have been proposed, including one that aims to increase the strength of the superconducting wire to resist peeling. For example, one method is to reinforce the outer periphery of the REBCO wire with a C-shaped metal member, strengthening the top surface of the superconducting layer and making it less likely to move, preventing peeling. Another method is to stack two REBCO wires and connect both ends in the width direction with solder, so that when thermal stress is applied, the force is borne only by these ends. Since the center part in the width direction is not connected to adjacent wires, the thermal stress is separated for each wire, and peeling stress is hardly applied.

[0005] The use of REBCO wire as a coil wire for high-temperature superconducting magnets involves a wide range of issues, and many patents have been filed for these issues. A particular issue relevant to the present invention is the tendency for the REBCO wire to deteriorate in superconducting properties due to internal delamination.

[0006] As mentioned above, REBCO wire has a multilayer structure with a protective layer (first metal layer) and a stabilizing layer (second metal layer). The tensile strength of the wire in the longitudinal direction can be controlled by the material and thickness of the metal substrate. However, the tensile strength in the direction perpendicular to the plane of the wire (the peeling direction for multilayer structures) is known to be very weak. In peel tests and cleavage tests, the metal substrate and superconducting layer peel off with a weak force. In coils impregnated with tape-shaped REBCO wire wound into a pancake shape, the force acting perpendicular to the plane of the wire is thermal stress generated during cooling to cryogenic temperatures. Superconducting coils, which require cryogenic cooling for current flow, delaminate and deteriorate during cooling. As described above, REBCO wire is susceptible to degradation due to thermal stress when wound into an impregnated coil. Therefore, proposals have been made to reduce delamination resistance by providing separate areas that peel off with a weaker force than REBCO wire or by increasing the strength of the wire itself. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 5269694 [Patent Document 2] Patent No. 5426231 [Patent Document 3] Patent No. 5512175 [Patent Document 4] Patent No. 6505565 [Patent Document 5] Patent No. 6678509 [Non-patent literature]

[0008] [Non-Patent Document 1] Y. Yanagisawa, TEION KOGAKU (J. Cryo. Super. Soc. Jap.) Vol.48 No.4 (2013), P151 Summary of the Invention [Problem to be solved by the invention]

[0009] When coiling REBCO wire, which is prone to peeling when subjected to thermal stress, it is necessary to reduce the amount of distortion in the superconducting layer due to the stress and prevent deterioration. When using the method of alleviating the peeling stress in the superconducting layer by providing separate peeling locations, as described above, it is necessary to manage the surface where the release material is applied to the insulating wire or REBCO wire. For example, if the release material is applied to the widthwise edge of the REBCO wire, peeling will occur, resulting in a decrease in strength and heat transfer properties. Furthermore, to prevent property degradation, the release material must be applied with precision to specific locations on the surfaces of the REBCO wire and insulating wire.

[0010] An embodiment of the present invention has been made taking these circumstances into consideration, and aims to simplify the application of release material to superconducting wire, and to configure a superconducting coil that is strong and does not reduce thermal conductivity characteristics. [Means for solving the problem]

[0011] A superconducting wire according to an embodiment of the present invention is a tape-shaped wire having a superconducting layer laminated together with other layers on a metal substrate, and a release material is applied to a portion of the surface of the wire, which reduces the adhesive strength with adhesive materials more than other portions. When viewed in cross section of the wire, coated areas where the release material is applied to one or more wide sides and uncoated areas where the release material is not applied to all sides are alternately arranged at least once in the longitudinal direction of the wire. [Effects of the Invention]

[0012] According to the embodiment of the present invention, the application of a release material to a superconducting wire can be simplified, and the superconducting coil can be configured to have a high strength and a low thermal conductivity. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 2 is a perspective view showing the superconducting wire of the first embodiment wound around a reel. [Figure 2] FIG. 3 is a cross-sectional view showing a portion of the superconducting wire of the first embodiment where a release material is not applied. [Figure 3] FIG. 3 is a cross-sectional view showing a portion of the superconducting wire according to the first embodiment where a release material is applied. [Figure 4] FIG. 1 is a cross-sectional view showing a conventional superconducting coil as a first comparative example. [Figure 5] FIG. 2 is a cross-sectional view showing the superconducting coil of the first embodiment. [Figure 6] FIG. [Figure 7] FIG. 10 is a cross-sectional view showing a conventional superconducting wire as a comparative example 2. [Figure 8] FIG. 10 is a cross-sectional view showing a conventional superconducting coil as a comparative example 2. [Figure 9] FIG. 10 is a cross-sectional view showing a conventional superconducting wire as Comparative Example 3. [Figure 10] FIG. 10 is a cross-sectional view showing a conventional superconducting coil as a comparative example 3. [Figure 11] 10 is a cross-sectional view showing a portion of a superconducting wire according to Modification Example 1 where a release material is applied. [Figure 12] FIG. 10 is a cross-sectional view showing a superconducting coil according to a first modified example. [Figure 13] 10 is a cross-sectional view showing a portion of a superconducting wire according to Modification Example 2 where a release material is applied. FIG. [Figure 14] FIG. 10 is a cross-sectional view showing a superconducting coil according to a second modification. [Figure 15] FIG. 11 is a plan view showing a superconducting coil according to a third modification. [Figure 16] FIG. 10 is a plan view showing a superconducting coil according to a fourth modification. [Figure 17] FIG. 13 is a plan view showing a superconducting coil according to a fifth modified example. [Figure 18] FIG. 10 is a perspective view showing a state in which a superconducting wire according to a second embodiment is wound around a reel. [Figure 19] FIG. 10 is a cross-sectional view showing a portion of the superconducting wire according to the second embodiment where a release material is not applied. [Figure 20] FIG. 10 is a cross-sectional view showing a portion of a superconducting wire according to a second embodiment where a release material is applied. [Figure 21] FIG. 4 is a cross-sectional view showing a superconducting coil according to a second embodiment. [Figure 22]FIG. 10 is a plan view showing a superconducting coil according to a third embodiment. [Figure 23] FIG. 10 is a plan view showing a superconducting coil according to a fourth embodiment. [Figure 24] FIG. 10 is a plan view showing a superconducting coil according to a fifth embodiment. [Figure 25] FIG. 10 is a plan view showing a superconducting coil according to a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] (First embodiment) Hereinafter, embodiments of a superconducting wire, a method for manufacturing a superconducting wire, a superconducting coil, and a coil device will be described in detail with reference to the drawings. First, a first embodiment will be described.

[0015] Reference numeral 1 in Fig. 1 denotes a superconducting coil of the first embodiment. This superconducting coil 1 is formed by winding a superconducting wire 3. The superconducting wire 3 is wound using a reel 9. Furthermore, a plurality of superconducting coils 1 are stacked to form a coil device 30 (Fig. 6). The superconducting coil 1 is exemplified as having a so-called pancake shape.

[0016] 6, each superconducting coil 1 has a central hole 31 (space) that passes through the center of the winding axis. Here, the direction parallel to the winding axis of the superconducting coil 1 is the coil axis direction 32, the direction in which the superconducting wire 3 is wound is the coil circumferential direction 33, and the direction in which the superconducting wire 3 is stacked by winding is the coil radial direction 34.

[0017] In the following description, in Figs. 2, 3, 7, 9, 11, 13, 19, and 20 which are cross-sectional views of superconducting wire 3, the vertical direction on the page is coil radial direction 34 and the horizontal direction on the page is coil axis direction 32. In Figs. 4, 5, 8, 10, 12, 14, 21, 22, 23, 24, and 25 which are cross-sectional views of superconducting coil 1, the vertical direction on the page is coil axis direction 32 and the horizontal direction on the page is coil radial direction 34. In addition, the cross-sectional views of superconducting coil 1 are cross-sectional views of one half of superconducting coil 1.

[0018] The coil device 30 has a plurality of superconducting coils 1 stacked in a coil axis direction 32, and the electrodes of the plurality of superconducting coils 1 are electrically connected to each other.

[0019] The superconducting wire 3 is a REBCO high-temperature superconducting wire. As shown in Fig. 2, the superconducting wire 3 is a tape-shaped wire having a superconducting layer 12 laminated together with other layers on a metal substrate 14. For example, the superconducting wire 3 is configured such that the superconducting layer 12 is formed on the metal substrate 14 via an intermediate layer 13, and the entire layer is covered with a stabilizing layer 10 made of a metal with good electrical conductivity such as copper (Cu) via a protective layer 11.

[0020] As shown in Fig. 1, a release material 5 is applied to a portion of the surface of the superconducting wire 3, which reduces the adhesive strength with the impregnating resin 8 (Fig. 5), which is an adhesive material (adhesive), compared to other portions. Along the longitudinal direction of the superconducting wire 3, coated portions 21, where the surface is coated with the release material 5, and uncoated portions 22, where the surface is not coated with the release material 5, are alternately (intermittently) provided multiple times. Note that it is sufficient that the coated portions 21 and the uncoated portions 22 are alternately provided at least once in the longitudinal direction of the superconducting wire 3.

[0021] On the surface of superconducting wire 3 , coated portion 21 is a region where stabilization layer 10 is exposed, and uncoated portion 22 is a region where stabilization layer 10 is covered with release material 5 .

[0022] 2 is a cross-sectional view of an uncoated portion 22 of superconducting wire 3. Uncoated portion 22 is a portion in the cross-sectional view of superconducting wire 3 where release material 5 is not applied to any of the sides.

[0023] FIG. 3 is a cross-sectional view of a coating portion 21 of a superconducting wire 3. The coating portion 21 is a portion in a cross-sectional view of the superconducting wire 3 where the release material 5 is coated on one or more wide sides. In the example of FIG. 3, the release material 5 is coated on one wide side and two opposite sides. Here, the one wide side is either the front or back side of the tape-shaped superconducting wire 3.

[0024] Here, the conventional technology will be described. Because the superconducting wire 3 is a thin, tape-shaped member, when the release material 5 is applied to one side, there is a high possibility that the release material 5 will also be applied to the two thin sides at both ends in the width direction. If the release material 5 is applied to the two ends, a problem will arise when winding the superconducting wire 3 as is to form a coil.

[0025] FIG. 4 is a cross-sectional view of a conventional superconducting coil 1 serving as Comparative Example 1. In Comparative Example 1, a release material 5 is continuously applied over the entire longitudinal length of superconducting wire 3. Superconducting wire 3 is then wound around coil bobbin 15 and fixed with impregnating resin 8 (adhesive), which is an adhesive material, to form a coil. Furthermore, coil side plates 16 made of a material such as FRP are attached to the upper and lower end surfaces of superconducting coil 1. Coil side plates 16 are fixed to superconducting coil 1 via impregnating resin 8, and superconducting coil 1 maintains its pancake shape.

[0026] The upper and lower end surfaces of the superconducting coil 1 are also used as surfaces for cooling the superconducting coil 1 by attaching metal members such as cooling plates (not shown) thereon. However, because the release material 5 is applied to both sides of the superconducting wire 3 at both ends in the width direction, there is a risk that the coil side plate 16 may peel off at this interface. Even if the coil side plate 16 does not peel off, the large surface area to which the release material 5 is applied increases the thermal resistance across the interface, which may result in a decrease in the cooling rate.

[0027] Therefore, as shown in Fig. 1, the superconducting coil 1 of the first embodiment is configured such that coated areas 21 where release material 5 is applied and uncoated areas 22 where release material 5 is not applied are alternately (intermittently) arranged in the longitudinal direction of the superconducting wire 3. Here, the superconducting wire 3 of the first embodiment is wound and coiled. Then, as shown in Fig. 5, in a cross-sectional view of the superconducting coil 1, the uncoated areas 22 where release material 5 is not applied and the coated areas 21 where release material 5 is applied are alternately arranged on two opposite sides in the width direction of the superconducting wire 3. In other words, the coated areas 21 and the uncoated areas 22 of the superconducting wire 3 are alternately arranged in the coil radial direction 34 (Fig. 6) of the superconducting coil 1.

[0028] In the superconducting coil 1 of the first embodiment, coated areas 21 and uncoated areas 22 of the release material 5 are alternately present on the superconducting wire 3, which makes it difficult for the coil side plates 16 to peel off from the superconducting coil 1. As a result, the heat transfer characteristics of the superconducting coil 1 can be improved.

[0029] The superconducting coil 1 is cooled by direct contact with cooling plates (not shown) attached to coil side plates 16 on both sides of the superconducting coil 1. In Comparative Example 1 shown in FIG. 4, many surfaces coated with release material 5 exist between the coil side plates 16 and the wound superconducting wire 3, and the heat transfer characteristics deteriorate due to the interface caused by peeling. In contrast, in the first embodiment shown in FIG. 5, the coil side plates 16 do not peel, and the reduction in the peeled interface that causes thermal resistance can be suppressed. Therefore, peeling and deterioration of the superconducting wire 3 due to thermal stress can be prevented while maintaining the heat transfer characteristics.

[0030] 7 and 8 are cross-sectional views of conventional superconducting wire 3 and superconducting coil 1 as Comparative Example 2. FIGS. 9 and 10 are cross-sectional views of conventional superconducting wire 3 and superconducting coil 1 as Comparative Example 3.

[0031] Comparative Example 2 in Fig. 8 has an ideal form, but it is difficult to form the release material 5 in this manner during manufacturing. On the other hand, Comparative Example 3 in Fig. 10 has no problem with heat transfer characteristics, but the influence of both ends in the width direction where the release material 5 is not formed, that is, the effect of avoiding deterioration, remains an issue. The first embodiment can solve such issues.

[0032] 11 and 12 are cross-sectional views of superconducting wire 3 and superconducting coil 1 according to Modification 1 of the first embodiment.

[0033] 11, at application location 21, release material 5 is applied over the entire periphery (all four sides) of superconducting wire 3 in a cross-sectional view. Even in this case, coil side plates 16 attached to both side surfaces of superconducting coil 1 will not peel off, as shown in FIG.

[0034] 13 and 14 are cross-sectional views of superconducting wire 3 and superconducting coil 1 according to Modification 2 of the first embodiment.

[0035] As shown in Modification 2, when release material 5 is applied to coated portion 21 along three sides of superconducting wire 3 in a cross-sectional view, some of release material 5 may also wrap around the remaining side ( FIG. 13 ). Even in this case, by applying release material 5 alternately in the longitudinal direction of superconducting wire 3, coated portions 21 and uncoated portions 22 of superconducting wire 3 are arranged alternately in coil radial direction 34 ( FIG. 14 ) in a cross-sectional view of superconducting coil 1. This is expected to have an effect of improving heat transfer characteristics.

[0036] Fig. 15 is a plan view of superconducting coil 1 according to Modification 3 of the first embodiment. In this plan view, superconducting wire 3 is actually wound in a spiral shape. However, in the example of Fig. 15, to facilitate understanding, one turn (one circumference) of superconducting wire 3 is illustrated as a circle, and multiple turns are illustrated as being arranged concentrically.

[0037] As shown in this modification 3, superconducting wire 3 wound around coil bobbin 15 has one turn (one circumference) of coated area 21 with release material 5 for two turns (two circumferences) of non-coated area 22. Coated areas 21 are provided at a rate of one for every three turns.

[0038] When applying release material 5 to superconducting wire 3 before winding, application areas 21 on superconducting wire 3 are set in advance based on the diameter of coil bobbin 15 and the thickness of superconducting wire 3. The range of applied areas 21 and non-applied areas 22 alternately provided in the longitudinal direction of superconducting wire 3 is set to become longer from the inner periphery to the outer periphery of superconducting coil 1. In this way, it is possible to reduce application areas 21 compared to the first embodiment and obtain the same effect.

[0039] Fig. 16 is a plan view of the superconducting coil 1 of the fourth modified example of the first embodiment. To facilitate understanding, Fig. 16 illustrates the areas 21 where the release material 5 is applied, and omits the areas 22 where the release material 5 is not applied.

[0040] In this modification 4, the length of each of application points 21 of release material 5 in the longitudinal direction of superconducting wire 3 is shorter than the circumferential length of superconducting coil 1. In other words, the length of each application point 21 is shorter than one turn (one circumference). In this way, it is possible to reduce application points 21 compared to the above-described modification 3, while still achieving the same effect.

[0041] Fig. 17 is a plan view of the superconducting coil 1 of the fifth modified example of the first embodiment. To facilitate understanding, Fig. 17 illustrates the application areas 21 of the release material 5, and omits the non-application areas 22.

[0042] In this modification 5, the lengths of coated areas 21 and uncoated areas 22 of release material 5 are set randomly in the longitudinal direction of superconducting wire 3. In other words, coated areas 21 and uncoated areas 22 do not need to have periodicity. In this way, it is not necessary to set the coating of release material 5 in consideration of the diameter of coil bobbin 15 and the thickness of superconducting wire 3, and manufacturing of superconducting wire 3 becomes easier.

[0043] Release material 5 used in superconducting wire 3 contains at least one of fluororesin, paraffin, grease, and silicone oil.

[0044] The method for manufacturing the superconducting wire 3 of the first embodiment also includes a step of bonding a fluororesin to the surface of the superconducting wire 3, or a step of spraying fluororesin powder as an aerosol onto the surface of the superconducting wire 3. In this way, it is desirable to use a surface-bonding type release material 5 or an aerosol type release material 5.

[0045] The method for producing the superconducting wire 3 of the first embodiment also includes a step of drying the release material 5, preferably at a temperature of 200° C. or less, more preferably at a temperature of 100° C. or less, after applying the release material 5 to the surface of the superconducting wire 3. The step of drying the release material 5 at a temperature of 200° C. or less includes a step of drying the release material 5 at room temperature.

[0046] In a typical method of forming a release layer by baking, the base material to be baked, i.e., the superconducting wire 3, needs to be heated to several hundred degrees during baking. However, this process carries a high risk of degrading the superconducting wire 3. For example, it is known that the resistance of the superconducting wire 3 begins to increase due to degradation when heated to about 220°C, and that this resistance becomes significant at 240°C (see, for example, Patent Document 5). On the other hand, since no increase in resistance occurs at about 195°C, it is known that the superconducting wire 3 is preferably heated to 200°C or less. Furthermore, based on these phenomena and the inventors' findings, it is known that the superconducting wire 3 is preferably heated to 100°C or less.

[0047] The surface-bonding type release material 5 or the aerosol type release material 5 can form a layer of the release material 5 on the superconducting wire 3 (base material) even at room temperature, and can then be dried. This means that there is no need to heat the superconducting wire 3 to several hundred degrees. Furthermore, by heating to 200°C or less, preferably about 50°C to 100°C, drying becomes more complete and the release properties improve. Furthermore, deterioration of the superconducting wire 3 can be prevented.

[0048] The method for manufacturing superconducting wire 3 according to the first embodiment also includes a step of drying release material 5 in a state where superconducting wire 3 is wound around reel 9.

[0049] In this way, in the process of manufacturing the superconducting coil 1, it is possible to manufacture the superconducting coil 1 without deteriorating the superconducting properties of the superconducting wire 3 due to heat. Furthermore, even when heated to 200°C or less, for example, at about 100°C, the releasability of the surface can be improved. This prevents deterioration of the superconducting wire 3 and improves its quality. Since the coating can be dried to a certain extent, for example, to the point where it cannot be removed by touch, even at room temperature, the coating can be applied, and the superconducting wire 3 can be batch-dried in an oven at 100°C, for example, while still wound on the reel 9.

[0050] The first embodiment contributes to preventing deterioration of the superconducting wire 3 and can improve the insulation characteristics between turns of the winding.

[0051] (Second embodiment) Next, a second embodiment will be described. Note that the same components as those shown in the above-described embodiment will be assigned the same reference numerals and redundant description will be omitted.

[0052] The superconducting wire 3 of the second embodiment has an insulating layer 6 formed on at least a portion of its surface. Furthermore, a release material 5 is applied to the surface of the superconducting wire 3 on which the insulating layer 6 is formed.

[0053] The first embodiment described above exemplifies a configuration in which release material 5 is applied directly to superconducting wire 3, while the second embodiment exemplifies a configuration in which release material 5 is applied to superconducting wire 3 coated with insulating layer 6. This configuration also contributes to preventing deterioration of superconducting wire 3, and can improve the insulation characteristics between winding turns, as in the first embodiment described above.

[0054] 18, an insulating layer 6 is coated in advance over the entire longitudinal length of a superconducting wire 3. On the superconducting wire 3, coated areas 21 and uncoated areas 22 of a release material 5 are formed alternately (intermittently) in the longitudinal direction. In other words, the coated areas 21 and uncoated areas 22 are provided alternately.

[0055] Fig. 19 is a cross-sectional view of a non-coated portion 22 of the superconducting wire 3. The surface of the superconducting wire 3 is covered with a stabilization layer 10. Fig. 20 is a cross-sectional view of a coated portion 21 of the superconducting wire 3. The surface of the superconducting wire 3 covered with the stabilization layer 10 is further coated with an insulating layer 6.

[0056] 21, when the superconducting wire 3 is wound into a coil, non-coated areas 22 where the release material 5 is not applied and coated areas 21 where the release material 5 is applied are alternately provided on both ends of the superconducting wire 3 in the width direction in a cross-sectional view of the superconducting coil 1. In this way, insulation between the turns can be ensured by coating with the insulating layer 6. Furthermore, by alternately providing the coated areas 21 and non-coated areas 22 of the release material 5, the same effect as in the first embodiment can be obtained.

[0057] It is also possible to configure a coil device 30 (FIG. 6) by stacking a plurality of superconducting coils 1 of the second embodiment. By configuring a plurality of superconducting coils 1 stacked and electrically connected, it is also possible to configure a high magnetic field coil.

[0058] According to the second embodiment, a portion not adhering to the impregnating resin 8 (adhesive) is formed inside the superconducting coil 1, that is, an application portion 21 of the release material 5 on the surface of the superconducting wire 3. Therefore, when thermal stress is applied, peeling occurs at this application portion 21, and the stress at the interface of the superconducting layer 12 (FIG. 20) where peeling is undesirable is alleviated.

[0059] Moreover, because release material 5 is applied alternately (intermittently) in the longitudinal direction of superconducting wire 3, non-coated areas 22 where release material 5 is not applied exist on the end face of superconducting coil 1, and are fixed with impregnating resin 8. As a result, it is possible to prevent deterioration of the superconducting properties due to peeling of superconducting layer 12. Moreover, because the areas fixed with impregnating resin 8 remain, there is no reduction in the thermal conductivity properties.

[0060] (Third embodiment) Next, a third embodiment will be described. Note that the same components as those shown in the above-described embodiments are denoted by the same reference numerals, and redundant description will be omitted.

[0061] 22, the superconducting coil 1 of the third embodiment is formed in a pancake shape by winding a superconducting wire 3 and an insulating wire 7 in an overlapping manner and fixing them together with an adhesive material, an impregnated resin 8. The insulating wire 7 is a tape-shaped wire and is made of an insulating material such as polyimide.

[0062] In a cross-sectional view of the superconducting coil 1, when focusing only on the superconducting wire 3, coated areas 21 where the release material 5 is applied and uncoated areas 22 where the release material 5 is not applied are provided alternately. The insulated wire 7 is provided between these coated areas 21 and uncoated areas 22.

[0063] According to the third embodiment, the insulating wire 7 can ensure insulation between turns. In other words, when the superconducting wire 3 is coiled, it is not necessary to add an insulating function to the superconducting wire 3, and this can contribute to improving the insulating properties. Furthermore, by alternately providing coated areas 21 and uncoated areas 22 of the release material 5, it is possible to obtain the same effect as in the first embodiment.

[0064] It is also possible to configure a coil device 30 (FIG. 6) by stacking a plurality of superconducting coils 1 of the third embodiment. By configuring a plurality of superconducting coils 1 stacked and electrically connected, it is also possible to configure a high magnetic field coil.

[0065] (Fourth embodiment) Next, a fourth embodiment will be described. Note that the same components as those shown in the above-described embodiments are denoted by the same reference numerals, and redundant explanations will be omitted.

[0066] 23, the superconducting coil 1 of the fourth embodiment is formed in a pancake shape by overlapping and winding the superconducting wire 3 and the reinforcing metal wire 17 and fixing them together with an adhesive material, i.e., an impregnating resin 8. The reinforcing metal wire 17 is a tape-shaped wire and is made of a strong material such as stainless steel.

[0067] In a cross-sectional view of the superconducting coil 1, when focusing only on the superconducting wire 3, coated areas 21 where the release material 5 is applied and uncoated areas 22 where the release material 5 is not applied are provided alternately. Further, reinforcing metal wires 17 are provided between these coated areas 21 and uncoated areas 22.

[0068] According to the fourth embodiment, the reinforcing metal wire 17 can be used as a reinforcing member for suppressing the amount of distortion caused by thermal stress and electromagnetic force applied to the superconducting coil 1. In other words, when the superconducting wire 3 and the reinforcing metal wire 17 are wound together, the mechanical strength against electromagnetic force increases and the amount of distortion can be reduced. Furthermore, by alternately providing coated areas 21 and uncoated areas 22 of the release material 5, the same effect as in the first embodiment can be obtained.

[0069] It is also possible to configure a coil device 30 (FIG. 6) by stacking a plurality of superconducting coils 1 of the fourth embodiment. By configuring a plurality of superconducting coils 1 stacked and electrically connected, it is also possible to configure a high magnetic field coil.

[0070] (Fifth embodiment) Next, a fifth embodiment will be described. Note that the same components as those shown in the above-described embodiments are denoted by the same reference numerals, and redundant explanations will be omitted.

[0071] As shown in FIG. 24, in the fifth embodiment, coated portions 21 and non-coated portions 22 are not provided in superconducting wire 3, but instead coated portions 21 and non-coated portions 22 are provided in insulated wire 7.

[0072] A release material 5 is applied to a portion of the surface of the insulated wire 7, which is a tape-shaped wire, to reduce the adhesive strength with the impregnated resin 8, which is an adhesive material (adhesive), compared to other portions. Along the longitudinal direction of the insulated wire 7, coated areas 21, where the release material 5 is applied to the surface, and uncoated areas 22, where the release material 5 is not applied to the surface, are alternately provided multiple times. Note that it is sufficient that the coated areas 21 and the uncoated areas 22 are alternately provided at least once in the longitudinal direction of the insulated wire 7.

[0073] The superconducting coil 1 of the fifth embodiment is formed in a pancake shape by winding a superconducting wire 3 and an insulating wire 7 in an overlapping manner and fixing them together with an impregnated resin 8, which is an adhesive material.

[0074] In a cross-sectional view of the superconducting coil 1, when only the insulated wire 7 is focused on, coated areas 21 where the release material 5 is applied and uncoated areas 22 where the release material 5 is not applied are provided alternately. The superconducting wire 3 is provided between these coated areas 21 and uncoated areas 22.

[0075] According to the fifth embodiment, by alternately providing the coated areas 21 and the uncoated areas 22 of the release material 5 on the insulating wire 7, it is possible to obtain the same effects as those of the first embodiment.

[0076] It is also possible to configure a coil device 30 (FIG. 6) by stacking a plurality of superconducting coils 1 of the fifth embodiment. By configuring a plurality of superconducting coils 1 stacked and electrically connected, it is also possible to configure a high magnetic field coil.

[0077] (Sixth embodiment) Next, a sixth embodiment will be described. Note that the same components as those shown in the above-described embodiments are denoted by the same reference numerals, and redundant explanations will be omitted.

[0078] As shown in FIG. 25, in the sixth embodiment, coated areas 21 and non-coated areas 22 are not provided in the superconducting wire 3, but instead coated areas 21 and non-coated areas 22 are provided in the reinforcing metal wire 17.

[0079] A release material 5 is applied to a portion of the surface of the reinforcing metal wire 17, which is a tape-shaped wire, to reduce the adhesive strength with the impregnating resin 8, which is an adhesive material (adhesive), compared to other portions. Along the longitudinal direction of the reinforcing metal wire 17, coated areas 21, where the surface is coated with the release material 5, and uncoated areas 22, where the surface is not coated with the release material 5, are alternately provided multiple times. Note that it is sufficient that the coated areas 21 and the uncoated areas 22 are alternately provided at least once in the longitudinal direction of the reinforcing metal wire 17.

[0080] The superconducting coil 1 of the sixth embodiment is formed in a pancake shape by winding a superconducting wire 3 and a reinforcing metal wire 17 in an overlapping manner and fixing them together with an impregnated resin 8, which is an adhesive material.

[0081] In a cross-sectional view of the superconducting coil 1, when focusing only on the reinforcing metal wire 17, coated areas 21 where the release material 5 is applied and uncoated areas 22 where the release material 5 is not applied are provided alternately. The superconducting wire 3 is provided between these coated areas 21 and uncoated areas 22.

[0082] According to the sixth embodiment, the coated areas 21 and non-coated areas 22 of the release material 5 are alternately provided on the reinforcing metal wires 17, thereby achieving the same effects as those of the first embodiment.

[0083] It is also possible to configure a coil device 30 (FIG. 6) by stacking a plurality of superconducting coils 1 of the sixth embodiment. By configuring a plurality of superconducting coils 1 stacked and electrically connected, it is also possible to configure a high magnetic field coil.

[0084] Inside the superconducting coil 1 fixed by the impregnating resin 8, there exists an unfixed release interface, and as a result, it is possible to form a release interface that prevents peeling and deterioration of the superconducting layer 12 (FIG. 3) due to thermal stress during cooling. Moreover, by applying the release material 5 intermittently, it is possible to alleviate stress inside the coil due to release properties and ensure heat transfer properties.

[0085] Furthermore, forming layers with intermittent release material 5 is more effective in preventing deterioration and ensuring heat transfer characteristics for superconducting coil 1 with a laminated structure that generates a stronger magnetic field. Also, by applying release material 5 to areas other than superconducting wire 3, the temperature constraints for applying release material 5 are relaxed, making it possible to create a coil at lower cost with less risk of deterioration.

[0086] The present invention has been described above based on each embodiment and each modified example, but the configuration applied in any embodiment or modified example may be applied to another embodiment or modified example, and the configurations applied in each embodiment and each modified example may be combined.

[0087] The above-described embodiment may be applied to either a high-temperature superconducting wire or a low-temperature superconducting wire, and exhibits a high effect with either superconducting wire 3. The above-described embodiment exemplifies the case where a high-temperature superconducting wire, which exhibits a particularly high effect, is used.

[0088] The superconducting coil 1 may be formed by overlapping and co-wound the superconducting wire 3, the insulating wire 7, and the reinforcing metal wire 17. This improves the insulating properties of the superconducting coil 1 and increases the mechanical strength, thereby providing the effect of preventing burnout, deterioration, and deformation due to a short circuit from deteriorating the superconducting properties.

[0089] In conventional superconducting coils 1, release material 5 for preventing deterioration is applied to one or both sides of superconducting wire 3 in a cross-sectional view, excluding the widthwise ends of superconducting wire 3, and is applied basically over the entire length in the longitudinal direction of superconducting wire 3. The reason why the widthwise ends of superconducting wire 3 are not included in the application is to prevent deterioration of the mechanical strength and heat transfer characteristics of superconducting coil 1.

[0090] In contrast, in the above-described embodiment, the wires (superconducting wire 3, insulating wire 7, reinforcing metal wire 17) have longitudinal surfaces (coated areas 21) on which the release material 5 is applied and surfaces (uncoated areas 22) on which it is not applied. Therefore, the surfaces on which the release material 5 is applied do not need to have partial areas on both ends of the wire in the width direction where the release material 5 is not applied. For example, the release material 5 may be applied solidly to one side of the wire. Instead, the mechanical strength and heat transfer characteristics of the superconducting coil 1 can be ensured by intermittently providing uncoated areas 22 on which the release material 5 is not applied at an appropriate frequency in the longitudinal direction of the wire.

[0091] Furthermore, when applying the release material 5 to the surface of the wire, there is no need to provide non-coated areas 22 at both ends in the width direction where the release material 5 is not applied, and application can be performed using a variety of simple application methods such as solid application from one side, material spraying, dip coating, etc. Moreover, by not applying the release material 5 in the longitudinal direction of the wire and providing non-coated areas 22 where the release material is fixed to the impregnating resin 8, the mechanical strength and heat transfer characteristics of the superconducting coil 1 can be improved.

[0092] According to at least one of the embodiments described above, coated areas 21 where release material 5 is coated and uncoated areas 22 where release material 5 is not coated are alternately provided in the longitudinal direction of superconducting wire 3. This simplifies the application of release material 5 to superconducting wire 3, and also makes it possible to configure superconducting coil 1 with high strength and without reducing thermal conductivity.

[0093] Although several 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, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments and modifications thereof are intended to be included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0094] 1...superconducting coil, 3...superconducting wire, 5...release material, 6...insulating layer, 7...insulating wire, 8...impregnated resin, 9...reel, 10...stabilizing layer, 11...protective layer, 12...superconducting layer, 13...intermediate layer, 14...metal substrate, 15...coil winding frame, 16...coil side plate, 17...reinforcing metal wire, 21...coated area, 22...non-coated area, 30...coil device, 31...central hole, 32...coil axial direction, 33...coil circumferential direction, 34...coil radial direction.

Claims

1. A tape-shaped wire having a superconducting layer laminated on a metal substrate together with other layers, a release material is applied to a portion of the surface of the wire, the release material reducing adhesive strength with the adhesive material more than other portions of the surface of the wire; In a cross-sectional view of the wire, coated areas where the release material is coated on one or more wide sides and uncoated areas where the release material is not coated on any of the sides are alternately provided at least once or more in the longitudinal direction of the wire. Superconducting wire.

2. an insulating layer having insulating properties is formed on at least a part of the surface of the wire; The release material is applied to the portion of the surface of the wire on which the insulating layer is formed. The superconducting wire according to claim 1 .

3. The release material includes at least one of fluororesin, paraffin, grease, and silicone oil.

3. The superconducting wire according to claim 1 or 2.

4. A method for producing the superconducting wire according to claim 1 or 2, the release material contains a fluororesin, The fluororesin is bonded to the portion of the surface of the wire, or a powder of the fluororesin is sprayed as an aerosol onto the portion of the surface of the wire. A method for manufacturing superconducting wire.

5. A method for producing the superconducting wire according to claim 1 or 2, After applying the release material to the surface of the wire, the release material is dried at a temperature of 200°C or less. A method for manufacturing superconducting wire.

6. The release agent is dried in a state where the wire is wound on a reel. The method for producing a superconducting wire according to claim 5.

7. The superconducting wire according to claim 1 or 2 is wound and fixed with the adhesive material to form a pancake shape. Superconducting coil.

8. A superconducting coil according to claim 7 is provided, The superconducting coils are stacked in the axial direction, and the electrodes of the superconducting coils are electrically connected to each other. Coil device.

9. The superconducting wire according to claim 1 or 2 and at least one of a tape-shaped insulating wire and a tape-shaped reinforcing metal wire are wound in an overlapping manner and fixed to each other with the adhesive material to form a pancake shape. Superconducting coil.

10. A method for manufacturing a superconducting coil, comprising: The superconducting coils are stacked in the axial direction, and the electrodes of the superconducting coils are electrically connected to each other. Coil device.

11. The wire is made of at least one of a tape-shaped insulating wire and a reinforcing metal wire, a release material is applied to a portion of the surface of the wire, the release material reducing adhesive strength with the adhesive material more than other portions of the surface of the wire; In a cross-sectional view of the wire, coated areas where the release material is coated on one or more wide sides and uncoated areas where the release material is not coated on any of the sides are alternately provided at least once or more in the longitudinal direction of the wire, a tape-shaped superconducting wire having a superconducting layer laminated on a metal substrate together with other layers, and at least one of the insulating wire and the reinforcing metal wire, which are wound in an overlapping manner and fixed to each other with the adhesive material, to form a pancake shape; Superconducting coil.

12. A method for manufacturing a superconducting coil, comprising: The superconducting coils are stacked in the axial direction, and the electrodes of the superconducting coils are electrically connected to each other. Coil device.

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