JP2018125147A - Connection part of superconductive cable and assembly method therefor - Google Patents

Abstract

An electrode and a superconducting wire can be suitably connected without causing leakage of solder and without lowering connection resistance and degrading superconducting characteristics. A superconducting cable having a superconducting conductor layer formed by winding a plurality of superconducting wires in a circle around a core material, and a cylindrical electrode into which the superconducting cable is inserted and joined to the superconducting conductor layer. The superconducting conductor layer and the cylindrical electrode are joined by soldering, and are provided across the outer surface of the cylindrical electrode and the superconducting conductor layer, and cover the space between the superconducting wire and the end of the cylindrical electrode. Is provided. [Selection] Figure 5

Description

  The present invention relates to a connecting portion of a superconducting cable formed by connecting to an electrode, and more particularly to a connecting portion of a superconducting cable in which a plurality of superconducting wires are wound around a core member and an assembling method thereof.

Conventionally, in a superconducting cable, a tape-shaped superconducting wire (hereinafter also referred to as “superconducting tape”) is spirally wound around the outer periphery of a core (former). Moreover, in superconducting cables, superconducting tapes are often concentrically arranged in multiple layers in order to enable large current transmission. When there are multiple layers between the core material and the superconducting tape layer, electrical insulation between the core material and the superconducting tape or between the superconducting tapes between the layers of the superconducting tapes arranged in multiple layers (ie, between the superconducting tapes) A presser tape is provided. In the case of having a multilayer superconducting tape layer, the presser tape also has a function of pressing the superconducting tape. As the superconducting _tape, REBa y _Cu 3 _{O z} system (RE is, Y, indicated Nd, Sm, Eu, one or more elements selected from Gd, and Ho, y ≦ 2 and z = 6.2 ˜7) is known. The _{REBa y Cu 3 O z Ba y} Cu 3 O z _{superconductors,} yttrium-based superconducting wire represented by YBa 2 _Cu 3 _{O 7} is typical.

  By the way, when applying a superconducting cable having a plurality of superconducting wires in the form of a layer on the outer periphery of the core as described above to a superconducting application device, the superconducting cable is a cylindrical metal terminal (electrode) connected to the superconducting application device. It is used by inserting and connecting to (for example, refer to Patent Document 1 and Patent Document 2). In addition, the connection part of such a cable and a metal terminal is called the connection part of a superconducting cable, and can also be called the termination | terminus part of a superconducting cable.

  In the structures shown in Patent Document 1 and Patent Document 2, the superconducting wire of the superconducting cable is connected to the inner peripheral surface of the metal terminal via solder inside the cylindrical metal terminal. In Patent Document 1, preliminary solder is applied to the inner peripheral surface of the metal terminal and the outer surface of the superconducting wire facing the inner peripheral surface. After the superconducting cable is inserted into the metal terminal, the metal terminal is heated from the outside to melt the preliminary solder, thereby joining the metal terminal and the superconducting cable.

  In Patent Document 2, a superconducting cable is covered with a semicircular arc-shaped divided piece and fixed to a portion where the outer peripheral protective layer is removed and the superconductor layer is exposed. Then, by pouring low melting point solder between the segment and the superconducting layer, the metal terminal formed by the segment and the superconducting layer are electrically joined.

Japanese Patent Laying-Open No. 2015-162367 Japanese Patent Laid-Open No. 2005-100776

  In recent years, as shown in Patent Document 1, in a structure in which a superconducting cable having a superconducting wire arranged on the outer periphery is inserted into a cylindrical metal terminal (electrode), as shown in Patent Document 2, a metal terminal and a metal terminal A structure is known in which solder is poured into a superconducting wire on the inside of the wire to join them together.

  At this time, as described in Patent Document 2, the gap between the end portion of the metal terminal and the superconducting wire in the metal terminal is fixed with a packing or a rubber-based masking material, and the solder poured into the metal terminal is The metal terminal is filled so as not to leak outside.

  However, if only the gap between the end of the metal terminal and the superconducting wire in the metal terminal is sealed with a packing or masking material, solder may leak out from the gap between the plurality of superconducting wires forming the layer. is there. In addition, in the configuration where the gap between the end of the metal terminal and the superconducting wire is sealed with a masking material, air bubbles are easily generated when the masking material is applied, or gaps are likely to occur when the masking material is applied. There is a problem in that so-called solder leakage occurs such that solder flows out to the outside. When solder leakage occurs, the sealing must be performed again and the metal terminals must be reheated in order to reflow the solder after the sealing, and the superconducting wire will be subjected to a long thermal history and the superconducting characteristics will deteriorate. Furthermore, there is a problem that the manufacturing cost is high.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a superconducting cable connecting portion and an assembling method thereof that can suitably connect an electrode and a superconducting wire without causing leakage of solder, keeping the connection resistance low and degrading superconducting characteristics. That is.

One aspect of the connecting portion of the superconducting cable of the present invention is:
A superconducting cable having a superconducting conductor layer formed by winding a plurality of superconducting wires in a circle around the core; and
A cylindrical electrode into which the superconducting cable is inserted and joined to the superconducting conductor layer;
Have
The superconducting conductor layer and the cylindrical electrode are joined by solder joint,
A configuration is adopted in which a resin coating layer is provided to span between the outer surface of the cylindrical electrode and the superconducting conductor layer, and covers between the superconducting wire and the end of the cylindrical electrode.

One aspect of the method of assembling the connecting portion of the superconducting cable of the present invention is
A superconducting wire having a superconducting conductor layer comprising a superconducting wire on a substrate, the superconducting wire having a superconducting wire wound around the core so that the superconducting layer is arranged on the outer peripheral side so as to be disposed on the outer peripheral side. In the superconducting cable connection method of connecting the cylindrical electrode and the superconducting conductor layer by inserting a cable into the cylindrical electrode,
Inserting the superconducting cable into the cylindrical electrode, burying a packing material between the end portion of the inner peripheral surface of the cylindrical electrode and the superconducting conductor layer in the cylindrical electrode,
In order to cover the embedded portion of the packing material from the outside of the cylindrical electrode, a masking material is provided across the opening edge of the cylindrical electrode and the portion of the superconducting conductor layer derived from the opening edge,
On the masking material, a resin coating layer is provided across the outer surface of the cylindrical electrode and the superconducting conductor layer, and after covering between the superconducting conductor layer and the end of the cylindrical electrode,
Solder is filled between the inner peripheral surface of the cylindrical electrode and the superconducting conductor layer through a solder injection hole formed in the cylindrical electrode.

  According to the present invention, a superconducting cable and an electrode in which a superconducting wire is wound around a core can be suitably connected without causing leakage of solder and suppressing connection resistance to a low level without degrading superconducting characteristics.

The side view which shows schematic structure of the connection part of the superconducting cable which concerns on embodiment 1 is a cross-sectional view taken along line AA in FIG. Sectional drawing which shows schematic structure of the connection part of the superconducting cable shown in FIG. Perspective view of superconducting cable showing the winding state of superconducting tape Sectional drawing which shows the principal part structure of the connection part of the superconducting cable which concerns on embodiment The figure which uses for description of the assembly method of the connection part of the superconducting cable of this Embodiment The figure which uses for description of the assembly method of the connection part of the superconducting cable of this Embodiment The figure which uses for description of the assembly method of the connection part of the superconducting cable of this Embodiment

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

<Configuration of superconducting cable>
FIG. 1 is a side view showing a schematic configuration of a connecting portion 100 of a superconducting cable according to an embodiment of the present invention. In the embodiment, in order to simplify the explanation, a case where the superconducting cable has a two-layer structure, that is, a two-layer superconducting tape (superconducting wire) is illustrated, but a one-layer structure, or a three-layer structure or more, The present invention is applicable even when there are three or more layers of superconducting tapes. 2 is a cross-sectional view taken along the line AA in FIG. 1, and shows a main part of the cylindrical electrode 120 of the connecting portion 100 viewed from the rear side (that is, the right side of FIG. 1 and the rear side of the cylindrical electrode 120). It is a block diagram.

  As shown in FIGS. 1 and 2, the connecting portion 100 includes a superconducting cable 110, a cylindrical lead electrode (hereinafter referred to as a cylindrical electrode) 120, and a resin coating layer 140 (140-1 to 140-4). Have. The cylindrical electrode 120 is provided by the number of layers of the superconducting tape. In the example of the present embodiment, since the number of layers of the superconducting tape of the superconducting cable 110 is two, two cylindrical electrodes 120-1 and 120-2 are provided. Lead cables 130-1 and 130-2 are electrically connected to the respective cylindrical electrodes 120-1 and 120-2. In actual use, superconducting cable 110 and cylindrical electrode 120 are immersed in a cryogenic liquid such as liquid nitrogen. And the electric current of the superconducting cable 110 is drawn out to the normal temperature part by the lead cable 130 through the cylindrical electrode 120. For example, the lead cable 130 is led into the air through a polymer sleeve (not shown) or the like.

  In the connecting portion 100, the superconducting cable 110 is passed through the cylindrical electrode 120, and both end portions (corresponding to the opening edge portion) of the cylindrical electrode 120 on the opening side are covered with the resin coating layer 140.

  FIG. 3 is a cross-sectional view showing a schematic configuration of a connecting portion of the superconducting cable shown in FIG.

  As shown in FIGS. 1 and 3, the superconducting cable 110 includes a core material (former) 111, a holding tape 112, a first superconducting tape 113, a holding tape 114, a second superconducting tape 115, and a holding tape 116.

  The core material 111 has a cylindrical shape and is composed of a stranded wire of Cu (copper). A pressing tape 112 made of a nonwoven fabric is wound around the outer periphery of the core material 111.

  On the outer periphery of the presser tape 112, as shown in FIG. 4, the first superconducting tape 113 constituting the first superconducting conductor layer is spirally spaced with a predetermined gap G between the tapes in the circumferential direction. It is wound in a shape. A presser tape 114 made of a nonwoven fabric is wound around the outer periphery of the first superconducting tape 113. Each of the presser tapes 112 and 114 is configured as a layered insulating portion by winding a single non-woven fabric in a spiral shape without a gap. The second superconducting tape 115 constituting the second superconducting conductor layer is spirally wound around the outer periphery of the presser tape 114 at a predetermined interval in the circumferential direction, like the first superconducting tape 113. It has been turned. On the outer periphery of the second superconducting tape 115, a presser tape 116 is wound in a spiral shape with no gap therebetween, like the presser tapes 112 and 114.

  In the example of the present embodiment, ten superconducting tapes per layer are wound spirally at a predetermined interval. That is, each superconducting tape layer formed by the first superconducting tape 113 and the second superconducting tape 115 is composed of ten superconducting tapes. In the superconducting cable 110, the number of superconducting tapes constituting each layer of the superconducting tape may be any number, may be composed of 10 or more such as 12, and may be at least one. As a layer made of the superconducting tapes 113 and 115, for example, ten superconducting tapes having a thickness of 0.1 mm and a width of 5 mm are wound at a twist pitch of 250 mm. As the presser tapes 112 and 114, for example, a non-woven fabric having a thickness of 0.2 mm and a width of 45 mm is wound in half wrap (that is, half of the tape width is wound in an overlapping manner).

As materials for the superconducting tapes 113 and 115, various conventionally proposed superconducting materials can be used. Here, the superconducting tape 113 and 115, the substrate and, REBa _y Cu ₃ O _z system formed along the substrate on the substrate (RE were selected Y, Nd, Sm, Eu, from Gd and Ho A superconducting layer which is a high-temperature superconducting thin film of one or more elements, wherein y ≦ 2 and z = 6.2 to 7.).

  The superconducting tape 115 has the same configuration as that of the superconducting tape 113 and is disposed around the core material 111 in the same manner as the superconducting tape 113. Therefore, only the configuration of the superconducting tape 113 will be described, and the description of the superconducting tape 115 will be omitted.

  Superconducting tape (YBCO superconducting wire) 113 has a tape shape, and is formed by sequentially laminating an intermediate layer, a tape-shaped superconducting layer, and a stabilizing layer on a tape-shaped metal substrate. In the superconducting tape 113, it is preferable that the laminated structure including the substrate, the intermediate layer, the superconducting layer, and the stabilizing layer is covered with a covering material made of a conductive material (copper).

  The substrate may be, for example, Ni—Cr (specifically, Ni—Cr—Fe—Mo based Hastelloy (registered trademark) B, C, X, etc.), W—Mo, Fe—Cr (eg, austenite). Stainless steel) or Fe—Ni (for example, non-magnetic composition type) and other low magnetic crystal grain non-oriented / heat resistant high strength metal substrates.

The intermediate layer has, for example, a plurality of layers such as a diffusion preventing layer for preventing element diffusion from the substrate from reaching the superconducting layer and an orientation layer for orienting the crystals of the superconducting layer in a certain direction. For example, the intermediate layer has an Al ₂ O ₃ layer as a first intermediate layer formed by sputtering on a substrate, and an RF sputtering method, an ion beam sputtering method, or the like is formed on the Al ₂ O ₃ layer. An amorphous LaMnO ₃ layer is formed as the second intermediate layer by sputtering. On this LaMnO ₃ layer, an MgO layer is formed as a third intermediate layer formed by the IBAD method or the like. On the MgO layer, there is a LaMnO ₃ layer as a fourth intermediate layer formed by a sputtering method, and a CeO ₂ layer as a fifth intermediate layer formed by a sputtering method or the like on the LaMnO ₃ layer. Have. The first intermediate layer is replaced with Al ₂ O ₃ by using ReZrO (Re: Y, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb, or one or more selected from them. May be formed by an RF-sputtering method or a MOD method. This first intermediate layer has high heat resistance and is a layer for reducing interfacial reactivity, and also functions as a bed layer used for obtaining the orientation of the film disposed thereon.

The superconducting layer is typically an yttrium superconductor (YBCO layer) represented by YBa ₂ Cu ₃ O ₇ . In the superconducting layer of the superconducting tape 113, oxide particles containing at least one of Zr, Sn, Ce, Ti, Hf, and Nb (particle size of 50 [μm] or less) are dispersed as magnetic flux pinning points. preferable. In this case, the TFA-MOD method using trifluoroacetate (TFA) is suitable as a method for forming the superconducting layer as the high-temperature superconducting thin film. For example, a Zr-containing oxide particle (BaZrO ₃ ) is added to a high-temperature superconducting thin film made of a RE-based superconductor by mixing a Zr-containing naphthenate having a high affinity with Ba into a Ba solution containing TFA. It can be distributed as flux pinning points. A known technique can be applied to the method of dispersing the magnetic flux pinning points in the high-temperature superconducting thin film (for example, JP 2012-059468 A). By dispersing the magnetic flux pinning points in the high-temperature superconducting thin film of the superconducting tape, even if the superconducting tapes 113 and 115 are used in a curved state, they are hardly affected by the magnetic field and exhibit stable superconducting characteristics.

  The stabilization layer is a noble metal such as silver, gold, platinum, or an alloy thereof, and is formed on the superconducting layer with a low-resistance metal. The stabilization layer disperses the performance degradation caused by the direct contact of the superconducting layer directly below with noble metals such as gold and silver, or materials other than their alloys, and the heat generated by accident currents and alternating currents. To prevent destruction and performance degradation due to heat generation.

  As described above, the plurality of superconducting tapes 113 and 115 include a superconducting layer on the substrate. The plurality of superconducting tapes 113 and 115 are concentric circles around the core material 111 in the superconducting cable 110 with the superconducting layer side surface facing the outer peripheral side and the substrate side surface facing the inner peripheral side. Arranged in a shape. That is, the superconducting tapes 113 and 115 are arranged in a multilayer manner by winding the superconducting layer on the outer peripheral side and the substrate on the inner peripheral side around the core material 111 and between the layered insulating portions made of the pressing tape. Has been.

  The superconducting cable 110 is actually provided with an electrical insulating layer, a superconducting shield layer, an external stabilizing layer, a corrugated tube, and the like on the outer peripheral side of the presser tape 116. However, since these members are removed at the terminal portions where the superconducting tapes 113 and 115 are connected to the cylindrical electrode 120, they are not shown in FIGS.

  Of the superconducting tapes 113 and 115 of the superconducting cable 110, the second superconducting tape 115 provided on the outermost peripheral side is formed on the inner surface of the cylindrical electrode 120-1 provided farthest from the terminal side of the superconducting cable 110. Directly connected via the solder layer 150 to be connected.

  The first superconducting tape 113 provided second from the outermost circumference (in the innermost circumference in the case of FIG. 1) is next to the end of the superconducting cable 110 (FIG. 1) next to the cylindrical electrode 120-1. In the case of this example, the electrodes are directly electrically connected via the solder layer 150 formed on the inner surface of the cylindrical electrode 120-2 provided on the right side of the drawing showing the most terminal side.

  That is, the superconducting cable 110 is disposed in a state where the superconducting conductor layer is disposed on the outer peripheral surface of the plurality of cylindrical electrodes 120-1 and 120-2 and is sequentially inserted from the terminal side of the superconducting cable 110. And in the superconducting cable 110 arrange | positioned in the cylindrical electrode 120 (120-1, 120-2) on the inner surface of the cylindrical electrodes 120-1 and 120-2, the layer by the superconducting tapes 115 and 113 on the outer peripheral side is sequentially arranged. Superconducting tapes 115 and 113 are connected to each other through the solder layer 150 toward the end side. In other words, the cylindrical electrodes 120 (120-1 and 120-2) are solder layers 150 formed by soldering to the superconducting tapes 113 and 115 located on the innermost surfaces (inner peripheral surfaces) inside. Are joined (so-called direct attachment).

  The cylindrical electrode 120 (120-1, 120-2) is cylindrical as a whole, and is formed of a conductive metal material such as Cu (copper). As is apparent from FIG. 2, the cylindrical electrodes 120 (120-1 and 120-2) have a cylindrical structure through which the superconducting cable 110 can penetrate. In addition, the cylindrical electrode 120 (120-1, 120-2) may be configured in a cylindrical shape by a plurality of semicircular arc-shaped divided bodies divided along the extending direction of the superconducting cable 110. In the case of the divided body, the divided body is covered with a predetermined position of the superconducting cable 110 and is formed in a cylindrical shape by airtightly fixing each other in the circumferential direction.

  The cylindrical electrode 120 (120-1, 120-2) is formed with a plurality of through-holes so that the inside and the outside communicate with each other. These through holes are a solder injection hole 124 for injecting solder from the outside to the inside of the cylindrical electrode 120 (120-1, 120-2), an air hole 126, and a confirmation hole 128 (see FIG. 5). The solder injection hole 124, the air hole 126, and the confirmation hole 128 are formed in the cylindrical electrode 120 so as to be aligned in a line in the axial direction and penetrate the cylindrical electrode 120. The solder injection hole 124, the air hole 126, and the confirmation hole 128 prevent the leakage of the solder to be filled, and also remove the internal air when the solder is filled, so that the cylindrical electrodes 120 (120-1, 120-2) can be removed. Preferably, the upper surface portion is formed in a line in the axial direction. The solder injection hole 124, the air hole 126, and the confirmation hole 128 may be provided anywhere as long as no solder leakage occurs during filling, but the position of the confirmation hole 128 is at the end (opening portion) of the cylindrical electrode 120. In order to confirm the filling condition of the solder into (), it is desirable to be located near the end. Note that three or more through holes that serve as the solder injection holes 124, the air holes 126, and the confirmation holes 128 may be provided. Specifically, at least one of the solder injection hole 124, the air hole 126, and the confirmation hole 128 may be provided. If there are confirmation holes 128 in the vicinity of both ends of the cylindrical electrode 120, the solder filling can be confirmed at each of the both ends.

  Inside the cylindrical electrode 120, an inner peripheral surface 122 (see FIG. 5) of the cylindrical electrode 120 and a superconducting conductor layer (a layer made of the superconducting tape 115) located in the outermost layer in the cylindrical electrode 120 are solder layers. 150 is joined (so-called direct attachment) so as to be energized.

  The inner diameter of cylindrical electrode 120 (120-1, 120-2) is substantially the same as the outer diameter of superconducting cable 110 arranged inside, or the outer diameter of superconducting cable 110 arranged inside. It is formed in a dimension in which a gap is formed between them. The connection between the cylindrical electrode 120-1 and the superconducting conductor layer constituted by the superconducting tape 115 and the connection between the cylindrical electrode 120-2 and the superconducting conductor layer constituted by the superconducting tape 113 have the same structure. It is. That is, both of the connections are connections between the inner peripheral surface 122 of the cylindrical electrode 120 and the superconducting conductor layer (the layer formed by the superconducting tapes 113 and 115) located in the outermost layer in the cylindrical electrode 120. Therefore, the cylindrical electrodes 120-1 and 120-2 are used as the cylindrical electrode 120, and the superconducting conductor layer of the superconducting tape 115 and the superconducting conductor layer of the superconducting tape 113, which are the outermost layers of the superconducting cable 110, are referred to as a superconducting conductor layer SC. This will be described with reference to FIG.

  FIG. 5 shows the main part of the joined state of the cylindrical electrode 120 (120-1, 120-2) and the superconducting conductor layer SC of the superconducting cable 110 (superconducting conductor layer of the superconducting tape 113, superconducting conductor layer of the superconducting tape 115). It is sectional drawing which shows a structure. In FIG. 5, the superconducting cable 110 (the layer of the superconducting tape 113, the pressing tape, and the core portion) inserted through the cylindrical electrode 120 is integrally illustrated for convenience.

  As shown in FIG. 5, between the both ends 120a and 120b of the cylindrical electrode 120 and the superconducting conductor layer SC on the outer peripheral surface of the superconducting cable 110 inserted into the cylindrical electrode 120, solder leakage prevention is provided. A packing material 160 is inserted.

  As the packing material 160, a sheet, an annular body, or a string-like body made of a soft material such as polytetrafluoroethylene (PTFE), silver, or indium may be used.

  Packing material between both ends 120a, 120b of cylindrical electrode 120 (120-1, 120-2) and a portion of outer surface (corresponding to the outer peripheral surface) 110a of superconducting cable 110 extending from both ends 120a, 120b. A masking material 170 is attached so as to block the portion where 160 is inserted from the outside.

  The masking material 170 is disposed at both end portions 120a and 120b of the cylindrical electrode 120 between the both end surfaces and the outer surface (superconductive conductor layer) 110a of the superconducting cable 110 exposed outside the cylindrical electrode 120. Covering the gap where the packing material 160 is interposed between both ends of the inner peripheral surface 122 of the cylindrical electrode 120 (120-1, 120-2) and the outer surface 110a of the superconducting cable. Specifically, the masking material 170 covers the outer peripheral surface of the superconducting cable 110 (the outer surface 110a of the superconducting conductor layer SC made of the superconducting tapes 113 and 115) from the outer edges of both ends of the cylindrical electrode 120.

  The masking material 170 may be any of a tape material, a paste material, and a coating material, but in this embodiment, a normal temperature solidified paste material is used. The masking material 170 is, for example, a synthetic rubber material that does not contain ammonia, and is, for example, a synthetic rubber that is solidified by heating at room temperature for 1 hour, at 65 ° C. for 30 minutes, and at 82 ° C. for 20 minutes (for example, a viscosity of 28000 to 30000 cps). Or the like. Specifically, it is desirable to use a paste containing a coloring agent or the like in 50 to 60% pure water and 30 to 40% synthetic rubber as a component of the paste-like masking material.

  Inside the inner peripheral surface 122 of the cylindrical electrode 120, between the inner peripheral surface 122 and the outer surface 110a of the superconducting tape 115 constituting the outermost layer of the superconducting cable 110, between the packing materials 160 of both end portions 120a and 120b. Is provided with a solder layer 150 formed of solder. The solder layer 150 is formed by solder injected through the solder injection hole 124 after the superconducting cable 110 is inserted into the cylindrical electrode 120. Solder layer 150 electrically connects cylindrical electrode 120 and superconducting cable 110 (specifically, superconducting conductor layer SC). Since the solder of the solder layer 150 is filled in the cylindrical electrode 120, the gap G (see FIG. 3) between the plurality of superconducting tapes 115 spirally arranged in the superconducting cable 110 is also filled.

  The resin coating layer 140 extends over the outer surface of the superconducting cable 110 (here, the superconducting layer of the superconducting tape 115 which is the outermost layer) 110 a and the outer peripheral surface 129 of the cylindrical electrode 120. The masking material 170 between the both ends 120a and 120b and the superconducting cable 110 is provided so as to completely cover from the outside.

  The resin coating layer 140 is formed of an epoxy resin. In the present embodiment, the resin coating layer 140 is a superconducting conductor made of epoxy resin on the outer surface of the masking material 170, the outer peripheral surface of the end of the cylindrical electrode 120-1, and the superconducting tape (113, 115) of the superconducting cable. It is formed by applying so as to straddle the outer surface of the layer SC. Thereby, the resin coating layer 140 completely closes the portion where the masking material 170 is provided and the gap between the masking material 170 itself. The resin coating layer 140 is an epoxy resin that is cured at room temperature, has a lower viscosity than the masking material 170 before being cured, and is used in combination with the masking material 170 to prevent solder leakage during solder filling. Note that the resin coating layer 140 also closes gaps between the superconducting tapes 115 wound in a spiral.

<Assembly Method of Superconducting Cable Connection 100>
A method for assembling the connecting portion of the superconducting cable will be described with reference to FIGS.

6 to 8 are views for explaining a method of assembling the connecting portion of the superconducting cable, and FIG. 6 is a view showing a state in which the packing material is disposed by inserting the superconducting cable into the cylindrical electrode. 7 is a diagram showing a state where a masking material is applied, and FIG. 8 is a diagram showing a state where a resin coating layer is provided.
Here, as a method for assembling the connecting portion 100 of the superconducting cable, a method of connecting the cylindrical electrode 120-1 and the superconducting cable 110 among the cylindrical electrodes 120 (120-1, 120-2) will be described. Note that, in the structure of the connecting portion having the cylindrical electrode 120-1 and the structure of the connecting portion having the cylindrical electrode 120-2, the superconducting cable 110 inserted through the cylindrical electrode 120-1 and the cylindrical electrode 120-2. The connection structure is substantially the same except that the configuration is different, and the connection method is also the same. The superconducting cable 110 inserted through the cylindrical electrode 120-1 has a configuration in which a layer (superconducting conductor layer) made of the second superconducting tape is disposed on the outermost periphery, that is, the core material 111, the pressing tape 112, the first The first superconducting tape 113, the presser tape 114, and the second superconducting tape 115 are provided. On the other hand, the superconducting cable 110 inserted through the cylindrical electrode 120-2 has a configuration in which the layer made of the first superconducting tape 113 is located on the outermost periphery, and the core material 111, the pressing tape 112, and the first superconducting cable. The tape 113 is provided. Therefore, the cylindrical electrode 120-1 is a superconducting conductor layer located inside the cylindrical electrode 120-1, and only the connection with the superconducting conductor layer of the superconducting tape 115 is described. The superconducting conductor layer located inside the cylindrical electrode 120-2, and the description of the method of connecting the superconducting tape 113 to the superconducting conductor layer is omitted.

  First, in the superconducting cable 110, the pressing tape 116 at a predetermined location is bent to expose the end of the second superconducting tape 115 connected to the cylindrical electrode 120-1 (see FIGS. 3 and 4). Further, the end portion of the superconducting tape 115 is attached to the cylindrical electrode 120-1 by peeling off the electrical insulating layer, the superconducting shield layer, and the external stabilizing layer provided on the outer peripheral side of the presser tape 116 at the terminal. It is exposed as the outer surface.

And as shown in FIG. 6, the superconducting cable 110 is inserted and fixed in the cylindrical electrode 120-1. At this time, the inner peripheral surface 122 of the cylindrical electrode 120-1 and the outer surface 110a of the superconducting cable 110 to be joined to the cylindrical electrode 120-1, that is, the outer surface of the superconducting conductor layer made of the superconducting tape 115 are made to face each other. In this state, fixing is performed with a gap H serving as the solder layer 150 being opened. The superconducting cable 110 is fixed in a state corresponding to the cylindrical electrode 120-1 in a member different from the portion inserted into the cylindrical electrode 120-1 or the cylindrical electrode 120-1. It is fixed to the part of the device provided with it.
Next, the outer surface (the outer surface 110a of the superconducting cable 110) of the superconducting conductor layer (the layer made of the superconducting tape 115) located at the outermost periphery of the superconducting cable 110 and the inner peripheral surface 122 of both ends 120a and 120b of the cylindrical electrode 120-1. The packing material 160 is inserted between the gap H and the gap H at both ends thereof.

  Next, as shown in FIG. 7, a masking material 170 is applied so as to cover the gap between both ends 120 a, 120 b of the cylindrical electrode 120-1 and the superconducting cable 110, that is, the portion that is sealed by the packing material 160. To do. Masking material 170 is disposed by being applied so as to straddle both end surfaces 121 and 123 of cylindrical electrode 120-1 and outer surface 110 a of superconducting cable 110. Note that the masking material 170 is cured by heating in this embodiment, but may be cured at room temperature.

  Next, as shown in FIG. 8, a resin coating layer 140 is formed so as to cover the masking material 170. The resin coating layer 140 is disposed so as to cover the masking material 170 itself after the masking material 170 is cured and to fill a gap covered by the masking material 170. In the present embodiment, the resin coating layer 140 is an epoxy resin, and covers the masking material 170 across the outer peripheral surface 129 of both ends 120a and 120b of the cylindrical electrode 120-1 and the outer surface 110a of the superconducting cable 110. Provided to cover completely. And the resin coating layer 140 hardens | cures at normal temperature, and obstruct | occludes the clearance gap between both ends and the superconducting cable 110 completely. At this time, the gap G between the superconducting tapes 115 located inside both ends is also completely closed.

  Next, the cylindrical electrode 120-1 is heated from the outside of the cylindrical electrode 120-1 by a heat source such as a heater. In this way, solder is injected from the solder injection hole 124 into the gap H in the cylindrical electrode 120-1 while heating the cylindrical electrode 120-1. Since the solder put in by heating is maintained in a molten state even inside the cylindrical electrode 120-1, the solder flows through the gap H without any gap, and the cylindrical electrode 120-1 including the gap H, the superconducting cable 110, Between. The amount of solder injected at this time is filled into the gap G between the plurality of superconducting tapes forming the cylindrical electrodes 120 (120-1, 120-2) and the outer diameter of each superconducting conductor layer, and each superconducting conductor layer. Based on the amount, the amount between the packing materials 170, and the like, the amount is preferably set in advance as an amount suitably filled between the inner peripheral surface 122 of the cylindrical electrode 120 and the outermost superconducting conductor layer of the superconducting cable 110. The connection portion between the both ends of the cylindrical electrode 120 and the superconducting cable 110 where solder leakage is likely to occur in the gap H is completely hermetically covered with the masking material 170 and the resin coating layer 140 in addition to the packing material 160. The solder is injected into the gap H without leakage.

  As described above, in the connecting portion 100 of the superconducting cable according to the present embodiment, the problem of solder leakage does not occur, the superconducting tape does not deteriorate, and the connection resistance can be kept low.

  That is, the connection resistance between the superconducting tapes 113 and 115 and the cylindrical electrode 120 can be kept low, the generation of Joule heat at the connection portion can be reduced, and further, since there is no variation, the drift is less likely to occur. The current capacity that can be applied to the current does not decrease.

  In addition, according to the present embodiment, since the inner peripheral surface 122 of the cylindrical electrode 120 and the superconducting tapes 113 and 115 passing through the cylindrical electrode 120 are directly connected, the connection location when connecting both of them. The connection resistance can be reduced as much as possible.

  Thus, in the connection part 100 of the superconducting cable 110, the plurality of superconducting tapes 113 and 115 and the cylindrical electrode 120 can be easily and suitably connected with reduced contact resistance via solder, which is reliable and suitable. Energizing capacity can be secured.

<Example 1>
On the Hastelloy (registered trademark) substrate, an Al ₂ O ₃ layer, an LaMnO ₃ layer, an MgO layer, an LaMnO ₃ layer, and a CeO ₂ layer are formed in this order, and an YBa layer is formed on the intermediate layer. ₂ Cu ₃ yttrium-based superconductors represented by O ₇ superconductor layer made of (YBCO layer), a REBa _y Cu ₃ O _z superconducting wire obtained by sequentially depositing a stabilizing layer of silver, thickness 0.12 [mm ] Superconducting cable 110 formed of a superconducting tape layer (for example, superconducting conductor layer 113) formed by winding 10 cores 111 of copper outer diameter 19mm and forming a superconducting tape layer (for example, superconducting conductor layer 113). The cylindrical electrode 120 having a thickness of 3 mm was soldered to assemble the connection portion 100 having the above-described configuration. When assembling the connecting portion 100, first, the superconducting cable 110 is inserted into the cylindrical electrode, and between the end portion of the inner peripheral surface of the cylindrical electrode 120 and the superconducting conductor layer (the layer made of the superconducting tape 113), A packing material 160 made of Teflon (registered trademark) is embedded. Next, a masking material 170 was provided at the opening edge of the cylindrical electrode 120 and at the portion of the superconducting conductor layer derived from the opening edge so as to cover the buried portion of the packing material 160 from the outside of the cylindrical electrode 120. Next, an epoxy-coated resin layer, which is the resin coating layer 140, is provided on the masking material 170 so as to span the outer surface of the cylindrical electrode 120 and the superconducting conductor layer, so that the superconducting conductor layer and the end of the cylindrical electrode 120 are aligned. I covered it. Thereafter, solder is filled between the inner peripheral surface 122 of the cylindrical electrode and the superconducting conductor layer via the solder injection hole 124 formed in the cylindrical electrode, and the cylindrical electrode 120 and the superconducting cable are connected via the solder. The superconducting conductor layer was connected. In the superconducting layer, 50 [nm] or less oxide particles containing Zr are dispersed as magnetic flux pinning points.

<Comparative Example 1>
In the connection part of the superconducting cable of Example 1, the cylindrical electrode was heated and soldered without using the resin coating layer, and the superconducting cable and the cylindrical electrode were connected.

<Comparative example 2>
In the connection part of the superconducting cable of Example 1, the cylindrical electrode was heated and soldered without covering both ends of the cylindrical electrode with the masking material and the resin coating layer, thereby connecting the superconducting cable and the cylindrical electrode. .

  As a result of visually confirming the connection portion of Example 1, solder did not leak out from the connection portion. On the other hand, as a result of visually confirming the connection portion of Comparative Example 1, there was a portion where solder leaked to the outside from the connection portion. Moreover, as a result of visually confirming the connection part of Comparative Example 2, there were many places where solder leaked to the outside from the connection part. Furthermore, in the state immersed in liquid nitrogen (@ 77K), the connection resistance between each superconducting wire and the cylindrical electrode is measured by the direct current four-terminal method (for example, the lead cable 130 so as to sandwich the soldered connection portion). Alternatively, when a DC ammeter and a DC voltmeter are connected between the outer surface of the cylindrical electrode 120 and the superconducting conductor layer derived from the cylindrical electrode, measurement is performed based on the respective values), Comparative Examples 1 and 2 As compared with the above, the connection resistance value of Example 1 was much smaller.

  Thus, it was found that by covering both ends of the cylindrical electrode 120-1 with a masking material and a resin coating layer, solder leakage is prevented and the connection resistance can be reduced.

  The connection part of the superconducting cable according to the present invention is such that the superconducting cable and the electrode in which the superconducting wire is wound around the core material, the solder resistance does not occur, the connection resistance is kept low, and the superconducting characteristics are not deteriorated. It has an effect of connection and is useful as a connection part of a multilayer superconducting cable.

DESCRIPTION OF SYMBOLS 100 Connection part 110 Superconducting cable 111 Core material 112,114,116 Holding tape 113,115 Superconducting tape 120,120-1,120-2 Cylindrical electrode 120a, 120b End part 122 Inner peripheral surface 124 Solder injection hole 126 Air hole 128 Confirmation hole 130, 130-1, 130-2 Lead cable 140, 140-1, 140-2, 140-3, 140-4 Resin coating layer 150 Solder layer 160 Packing material 170 Masking material

Claims (6)

A superconducting cable having a superconducting conductor layer formed by winding a plurality of superconducting wires in a circle around the core; and
A cylindrical electrode into which the superconducting cable is inserted and joined to the superconducting conductor layer;
Have
The superconducting conductor layer and the cylindrical electrode are joined by solder joint,
A resin coating layer provided between the outer surface of the cylindrical electrode and the superconducting conductor layer and covering between the superconducting wire and an end of the cylindrical electrode;
Superconducting cable connection. The resin coating layer is an epoxy resin.
The connection part of the superconducting cable according to claim 1. A masking material is provided between the outer surface of the superconducting conductor layer and the connecting portion at the end of the inner peripheral surface of the cylindrical electrode, and the resin coating layer.
The connection part of the superconducting cable according to claim 1 or 2. The masking material is a synthetic rubber material containing no ammonia.
The connection part of the superconducting cable according to claim 3. The superconducting wire is provided with a superconducting layer via an intermediate layer on the substrate, and the substrate is wound toward the inner peripheral side so that the superconducting layer is disposed on the outer peripheral side,
The connection part of the superconducting cable as described in any one of Claim 1 to 4. A superconducting wire having a superconducting conductor layer comprising a superconducting wire on a substrate, the superconducting wire having a superconducting wire wound around the core so that the superconducting layer is arranged on the outer peripheral side so as to be disposed on the outer peripheral side. In a method of assembling a superconducting cable in which a cable is inserted into a cylindrical electrode to connect the cylindrical electrode and the superconducting conductor layer,
Inserting the superconducting cable into the cylindrical electrode, burying a packing material between the end portion of the inner peripheral surface of the cylindrical electrode and the superconducting conductor layer in the cylindrical electrode,
In order to cover the embedded portion of the packing material from the outside of the cylindrical electrode, a masking material is provided across the opening edge of the cylindrical electrode and the portion of the superconducting conductor layer derived from the opening edge,
On the masking material, a resin coating layer is provided across the outer surface of the cylindrical electrode and the superconducting conductor layer, and after covering between the superconducting conductor layer and the end of the cylindrical electrode,
Filling the space between the inner peripheral surface of the cylindrical electrode and the superconducting conductor layer via the solder injection hole formed in the cylindrical electrode,
Assembling method of superconducting cable.

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