Superconducting laminated conductor, superconductive cable and electric propulsion system

Abstract

To realize light weight in a superconducting laminated conductor itself and improved ease of handling during superconducting cable production, while securing insulation between superconducting wires in a superconducting laminated conductors obtained by laminating multiple tape-shaped superconducting wire materials.SOLUTION: A superconducting laminated conductor is composed of multiple tape-shaped superconducting wires laminated together. The multiple tape-shaped superconducting wires include: a wire-covered type tape superconducting wire, which has an insulating layer on both the front and back surfaces of the wire, and a wire-exposed type tape superconducting wire, which does not have an insulating layer on the surfaces of the wire. The wire-covered type tape superconducting wire and the wire-exposed type tape superconducting wire are laminated alternately.SELECTED DRAWING: Figure 6B

Description

[Technical Field]

[0001] The present invention relates to a superconducting laminated conductor, a superconducting cable, and an electric propulsion system. [Background technology]

[0002] Previously, superconducting cables have been known that use superconducting wires that become superconducting at cryogenic temperatures as conductors and can transmit large currents with low loss. For example, in the propulsion systems of aircraft and other flying objects, where electrification is being considered to reduce CO2 emissions, there is a growing need for lightweight, highly efficient, and high-output superconducting technology. To realize such propulsion systems, development is underway on superconducting cables capable of carrying large currents that are suitable for supplying power to electric motors that will replace jet engines.

[0003] For example, Patent Document 1 describes a three-phase coaxial superconducting cable. The superconducting cable described in Patent Document 1 has a thermal insulated pipe with a double-pipe structure composed of a thermally insulated inner pipe and a thermally insulated outer pipe made of metal, and houses a cable core with multiple superconducting layers stacked coaxially inside the thermally insulated inner pipe, and circulates a refrigerant through it, with the space between the thermally insulated inner pipe and the thermally insulated outer pipe being kept in a vacuum state to achieve thermal insulation.

[0004] The superconducting cable described in Patent Document 2 has a configuration in which a plurality of superconducting laminated conductors, each of which is made up of a plurality of laminated tape-shaped superconducting wires, are arranged in a multi-core structure within the internal space of a thermal insulation pipe. This configuration ensures high current carrying performance, while also simplifying and reducing the weight of the overall superconducting cable. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2020-119769 [Patent Document 2] Patent No. 7383839 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in order to realize, for example, the above-mentioned electrically powered flying object, further weight reduction of the superconducting cable is desired.

[0007] The present inventors have focused on the fact that reducing the weight of the superconducting laminated conductor itself is important for reducing the weight of superconducting cables that use a superconducting laminated conductor formed by laminating a plurality of tape-shaped superconducting wires, particularly superconducting cables that use a plurality of superconducting laminated conductors. As a result of extensive research into reducing the weight of the superconducting laminated conductor itself, the present inventors have devised the present invention, which can achieve not only weight reduction but also improved ease of work without impairing the insulation between the superconducting wires.

[0008] An object of the present invention is to provide a superconducting laminated conductor, a superconducting cable, and an electric propulsion system that can achieve a reduction in weight of the superconducting laminated conductor itself and improved ease of work during the manufacture of the superconducting cable, while ensuring insulation between the superconducting wires in a superconducting laminated conductor formed by stacking a plurality of tape-shaped superconducting wires. [Means for solving the problem]

[0009] One aspect of the superconducting laminated conductor according to the present invention is A superconducting laminated conductor formed by laminating a plurality of tape-shaped superconducting wires, The plurality of tape-shaped superconducting wires are a wire-coated tape-shaped superconducting wire having insulating layers on the front and back surfaces of the wire; a wire-exposed tape-shaped superconducting wire having no insulating layer on the front and back surfaces of the wire, The wire-covered tape-shaped superconducting wires and the wire-exposed tape-shaped superconducting wires were alternately stacked.

[0010] One aspect of the superconducting cable according to the present invention is A plurality of the above superconducting laminated conductors are provided, The device further includes a thermal insulation pipe having an internal space through which a refrigerant flows during use, and in which a plurality of the superconducting laminated conductors are arranged in a multi-core structure and insulated from one another within the internal space.

[0011] One aspect of the electric propulsion system according to the present invention is An electric propulsion system mounted on a transportation device, a power generating system including the above superconducting cable, a power source, and an electric motor; the superconducting cable connects the power source and the electric motor; The electric motor is driven by supplying electric power via the superconducting cable to propel the transportation equipment. [Effects of the Invention]

[0012] According to the present invention, in a superconducting laminated conductor in which a plurality of tape-shaped superconducting wires are stacked, it is possible to ensure insulation between the superconducting wires, while achieving weight reduction for the superconducting laminated conductor itself and improving workability during the manufacture of the superconducting cable. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram schematically showing the configuration of an electric propulsion system which is an application example of a superconducting cable including a superconducting laminate according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram schematically showing a cross-sectional structure of a superconducting cable including a superconducting laminated conductor according to an embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing a schematic view of a laminated structure of a single superconducting wire. [Figure 4] FIG. 4 is a diagram showing a schematic diagram of a connection structure between a superconducting laminate and electrodes according to an embodiment of the present invention. [Figure 5] FIG. 5 is a side view of the appearance of the superconducting laminate according to the embodiment of the present invention. [Figure 6A] FIG. 6A is a diagram schematically showing a cross section of a superconducting laminate according to an embodiment of the present invention. [Figure 6B]FIG. 6B is a diagram showing the cross section shown in FIG. 6A in a state where a plurality of tape-shaped superconducting wires are disassembled from one another. [Figure 7A] FIG. 7A is a diagram schematically showing an end (longitudinal end) of a superconducting laminate according to an embodiment of the present invention, viewed from the front side. [Figure 7B] FIG. 7B is a diagram schematically showing a wire-covered tape-shaped superconducting wire in a superconducting laminate according to an embodiment of the present invention. [Figure 8] FIG. 8 is a diagram showing a schematic view of an end portion exposed structure of a superconducting laminate according to an embodiment of the present invention. [Figure 9A] FIG. 9A is a diagram schematically showing an end (longitudinal end) of a superconducting laminate according to Modification 1 of the embodiment of the present invention, viewed from the front side. [Figure 9B] FIG. 9B is a diagram showing the end portion shown in FIG. 9A in a state where a plurality of tape-shaped superconducting wires are disassembled from one another. [Figure 10A] FIG. 10A is a diagram schematically showing an end (longitudinal end) of a superconducting laminate according to Modification 2 of the embodiment of the present invention, viewed from the front side. [Figure 10B] FIG. 10B is a diagram schematically showing the insulating tape in the superconducting laminate according to the second modification of the embodiment of the present invention, developed into a plane. [Figure 11] FIG. 11 is a diagram showing a schematic view of an end (longitudinal end) of a superconducting laminate according to a third modification of the embodiment of the present invention, viewed from the front side. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, superconducting laminated conductors according to embodiments of the present invention will be described with reference to the drawings.

[0015] (Embodiment 1) FIG. 1 is a diagram schematically illustrating the configuration of an electric propulsion system that is an application example of a superconducting cable including a superconducting laminate according to an embodiment of the present invention.

[0016] The electric propulsion system 1 is mounted on a transportation device to propel the transportation device. The transportation device may be, for example, an aircraft. The electric propulsion system 1 includes a turbine 11, a fuel tank 12, an output shaft 13, a superconducting generator 14, an inverter 15, a superconducting motor 16, an output shaft 17, a propeller 18, a cooling system 19, and power transmission cables 20 and 21. Here, the aircraft includes not only airplanes, but also helicopters, flying drones, and other aircraft that fly through the air by generating at least one of lift and propulsion using rotors. The aircraft may be manned or unmanned. The propeller 18 may be a so-called ducted fan.

[0017] In the electric propulsion system 1, a turbine 11 is rotated by gas obtained by burning fuel in a fuel tank 12, and the power of this rotation is extracted through an output shaft 13 and input to a superconducting generator 14 (an example of an electric power device and an electric power source), causing the superconducting generator 14 to generate electricity. The electric propulsion system 1 transmits the power generated by the superconducting generator 14 to an inverter 15 (an example of an electric power device and an electric power source) via a power transmission cable 20, where the inverter 15 converts the DC power to AC power. The electric propulsion system 1 supplies the AC power to a superconducting motor 16 (an example of an electric power device and an electric motor) via a power transmission cable 21, causing the superconducting motor 16 to rotate, which in turn rotates a propeller 18 connected to the superconducting motor 16 via an output shaft 17, generating propulsion force.

[0018] Superconducting cable 100 (described in detail later) is used as power transmission cables 20, 21 between power devices in electric propulsion system 1. In this embodiment, power transmission cable 20 is a cable for direct current and power transmission cable 21 is a cable for alternating current, but both function as power supply cables from the power source (superconducting generator 14 and inverter 15) to the electric motor (superconducting motor 16). Superconducting cable 100 can be used as either power transmission cable 20 or 21.

[0019] The electric propulsion system 1 is an all-superconducting system that uses superconductors as conductors in various electric power devices such as the superconducting generator 14 and the superconducting motor 16, as well as in the power transmission cables 20, 21 (superconducting cable 100). This makes it possible to realize an electric propulsion system that can obtain high power output with extremely high efficiency.

[0020] In order to maintain the superconducting state of the superconductor during use, the electric propulsion system 1 uses a cooling system 19 to circulate liquid nitrogen (an example of a refrigerant) inside the electric propulsion system 1, thereby cooling the superconductor to an extremely low temperature state.

[0021] The electric propulsion system 1 is used, for example, as an electric propulsion system for an aircraft (an example of transportation equipment) that propels the aircraft. In this case, the power source of the aircraft is replaced from a conventional jet engine with a superconducting motor 16. As a result, even if the same jet fuel as before is used as fuel, fuel consumption can be significantly reduced, thereby significantly reducing CO2 emissions. Furthermore, while a conventional electric motor made of an iron core and copper wire requires more than 10 times the weight of a jet engine to generate the propulsive force necessary for the aircraft's flight, the electric propulsion system 1 using the superconducting motor 16 can theoretically generate more power than a jet engine with the same weight as a jet engine, for example, more than twice the power required to propel the aircraft. In other words, an electric propulsion system for an aircraft can be realized.

[0022] Incidentally, to more efficiently propel an aircraft using the electric propulsion system 1, it is necessary to reduce the weight and size of the entire electric propulsion system 1. To achieve this, it is necessary to reduce the weight and simplify the configuration not only of the power equipment but also of the power transmission cables 20 and 21. In this embodiment, as described below, a superconducting cable 100 is provided that can simplify and lighten the overall configuration while maintaining high current performance. Therefore, by using this superconducting cable 100 in the electric propulsion system 1, it is possible to achieve the overall weight and size reduction of the electric propulsion system 1 required to more efficiently propel an aircraft. This will contribute to Goal 7 of the Sustainable Development Goals (SDGs), "Ensure access to affordable, reliable, sustainable and modern energy for all" and Goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation," which are international goals aimed at achieving a sustainable and better world by 2030 as set forth in the "2030 Agenda for Sustainable Development" adopted at the United Nations Summit in September 2015.

[0023] FIG. 2 is a diagram schematically showing the cross-sectional structure of superconducting cable 100. As shown in FIG.

[0024] The superconducting cable 100 has a plurality of cable cores 120 and a thermal insulation pipe 150. In this embodiment, the number of cable cores 120 is three, and therefore the superconducting cable 100 is suitable for use as a three-phase cable or the like. The number of cable cores 120 may be two or more, and may be any number as long as the superconducting cable 100 can be made thinner and simpler.

[0025] Each cable core 120 includes a superconducting laminate 122 according to the present embodiment and an interphase insulating sheet 124 .

[0026] Each superconducting laminate 122 is a laminate formed by stacking a plurality of tape-shaped superconducting wires 1222. Here, "tape-shaped" means that the shape is long and planar, and the planar dimensions are sufficiently large compared to the thickness. By configuring the superconducting laminate 122 with the tape-shaped superconducting wires 1222, the cross-sectional area in the axial direction of the superconducting laminate 122 when the same current is passed through it can be significantly reduced. Therefore, the thermal insulation pipe 150 that houses the plurality of superconducting laminates 122 can be significantly reduced in diameter and weight.

[0027] As shown in FIG. 3, the strands 1222s of the individual tape-shaped superconducting wires 1222 constituting the superconducting laminated conductor 122 have a laminated structure in which an intermediate layer 1222c, a superconducting layer 1222d, and a protective layer 1222e are laminated in this order on the upper surface of a substrate 1222b, and stabilizing layers 1222a and 1222f are laminated on the upper surface of the protective layer 1222e and the lower surface of the substrate 1222b, respectively. The substrate 1222b is, for example, a metal substrate. The intermediate layer 1222c has a structure in which, for example, an Al2O3 layer, a LaMnO3 layer, an MgO layer, a LaMnO3 layer, and a CeO2 layer are laminated in this order. The superconducting layer 1222d is a layer made of a superconductor, and in this embodiment, is made of an oxide superconductor such as an yttrium-based superconductor (REBa2Cu3O4) having a relatively high critical temperature exceeding the boiling point of liquid nitrogen (77K). 7-δ RE represents at least one element selected from the group consisting of Y, Nd, Sm, Gd, Dy, Eu, Er, Yb, Pr, and Ho. The protective layer 1222e is, for example, an Ag layer. The stabilizing layers 1222a and 1222f are, for example, Cu layers. The thickness of each tape-shaped superconducting wire 1222 is approximately 250 μm at most. Since known techniques can be applied to the laminated structure, manufacturing method, and dimensions such as thickness of the above-mentioned tape-shaped superconducting wire, detailed description thereof will be omitted here.

[0028] As described above, the superconducting laminate 122 is formed by stacking a plurality of tape-shaped superconducting wires 1222. The number of stacked tape-shaped superconducting wires 1222 is not particularly limited, but can be determined based on the operating current value required for propulsion of the aircraft by the electric propulsion system 1.

[0029] The superconducting laminated conductor 122 according to this embodiment uses two types of tape-shaped superconducting wires 1222. Specifically, the two types of tape-shaped superconducting wires 1222 are a wire-coated tape-shaped superconducting wire 1222-1 and an exposed-wire tape-shaped superconducting wire 1222-2. The wire-coated tape-shaped superconducting wire 1222-1 and the exposed-wire tape-shaped superconducting wire 1222-2 have the same configuration as the laminated structure shown in FIG. 3, but differ in whether or not they have an insulating layer on their outer circumferential surfaces. The configuration of the superconducting laminated conductor 122 including both the wire-coated tape-shaped superconducting wire 1222-1 and the exposed-wire tape-shaped superconducting wire 1222-2 will be described later. In the following description, when there is no particular distinction between the wire-covered tape-shaped superconducting wire 1222-1 and the wire-exposed tape-shaped superconducting wire 1222-2, the term "tape-shaped superconducting wire 1222" is used as a general term.

[0030] FIG. 4 is a diagram schematically illustrating a connection structure between a superconducting laminate 122 and an electrode 102. The ends of the superconducting laminate 122 are housed in grooves in the electrodes 102 and connected. The superconducting laminate 122 is configured, for example, by stacking a total of 30 tape-shaped superconducting wires 1222. The electrodes 102 are connected to, for example, a superconducting generator 14, an inverter 15, a superconducting motor 16, and the like. Electric power is supplied to the electrodes 102, for example, from the front and back sides in the stacking direction of the superconducting laminate 122, and is passed through each superconducting laminate 122 via the electrodes 102.

[0031] The superconducting laminate 122 is stacked such that 15 tape-shaped superconducting wires 1222 (an example of the upper half) stacked between the center in the stacking direction and the top surface 122U of the superconducting laminate 122 face upward, and 15 tape-shaped superconducting wires 1222 (an example of the lower half) stacked between the center in the stacking direction and the bottom surface 122L of the superconducting laminate 122 face downward. In other words, on the front side, i.e., on the upper half of the tape-shaped superconducting wire 1222, the superconducting layer 1222d is located above the substrate 1222b, and on the back side, i.e., on the lower half of the tape-shaped superconducting wire 1222, the superconducting layer 1222d is located below the substrate 1222b.

[0032] As a result, the length of the conduction path of the superconducting laminate 122 can be shortened whether it is located on the front side (top surface 122U side) or the back side (bottom surface 122L). Therefore, the influence on conduction due to the orientation of the superconducting laminate 122, i.e., the orientation of the cable core 120, can be suppressed. Here, the conduction path refers to the length of the path along which current flows from the position where power is supplied to the electrode 102 to each superconducting layer 1222d of the multiple tape-shaped superconducting wires 1222.

[0033] Although not shown in FIG. 4 , each of the wire-coated tape-shaped superconducting wires 1222-1 among the tape-shaped superconducting wires 1222 is wound with a wire insulating sheet 126 (see FIGS. 5, 6A, 6B, 7A, and 7B) around its outer periphery, thereby insulating it from the other tape-shaped superconducting wires 1222. The wire insulating sheet 126 is made of a material with a smooth outer surface, such as a heat-resistant and voltage-resistant resin. The wire insulating sheet 126 may be, for example, a polyimide tape. In the following description, for convenience, it will be referred to as an "insulating tape 126." Note that, for example, Kapton (registered trademark) tape is suitable as the insulating tape 126. In each superconducting laminate conductor 122, adjacent tape-shaped superconducting wires 1222 in the stacking direction can slide against each other. This ensures slidability between the stacked tape-shaped superconducting wires 1222. Furthermore, by forming the tape-shaped superconducting wires 1222 located on the uppermost surface 122U and the lowermost surface 122L as the wire-coated tape-shaped superconducting wires 1222-1, it is possible to obtain a sliding property between the wire-coated tape-shaped superconducting wires 1222-1 and the outer peripheral interphase insulating sheet 124. This ensures the flexibility and bendability of the superconducting laminate conductor 122, and therefore the flexibility and bendability of the superconducting cable 100.

[0034] An interphase insulating sheet 124 is wound around the outer periphery of the superconducting laminate conductor 122. The interphase insulating sheet 124 is made of an insulating material. For example, kraft paper can be used for the interphase insulating sheet 124. In this embodiment, the interphase insulating sheet 124 is wound multiple times around the outer periphery of each superconducting laminate conductor 122, so that the superconducting laminate conductors 122 can be insulated from each other by the interphase insulating sheet 124 alone. In other words, interphase insulation between the superconducting laminate conductors 122 can be ensured without the need for any other insulating structures. This allows the superconducting cable 100 to have a simplified configuration and a lighter weight. For example, the thickness of the multiple-wound interphase insulating sheet 124 is 2 mm, which is sufficiently thin that the diameter of the cable core 120 does not increase significantly even with multiple windings.

[0035] The interphase insulating sheet 124 is spirally wound with gaps 127 in the axial direction as shown in Fig. 5. The gaps 127 between the interphase insulating sheet 124 are, for example, about 1 to 2 mm. This makes it possible to prevent wrinkles and the like from occurring when the superconducting laminate 122 is bent. Alternatively, the interphase insulating sheet 124 may be wound so as to completely cover the outer periphery of the superconducting laminate 122 without leaving gaps 127.

[0036] The configuration for interphase insulation is not limited to the configuration using the above-mentioned interphase insulation sheet 124, and other known configurations may be used, such as the one described as embodiment 2 in Patent Document 2, in which the thickness of the interphase insulation sheet 124 is formed thin enough to maintain the laminated state of the superconducting laminate conductor 122 using an interphase insulation spacer (not shown).

[0037] The thermal insulation pipe 150 is a tubular member that can accommodate a plurality of cable cores 120 as a single superconducting cable 100 and that can be filled with and circulate a refrigerant for cooling the cable cores 120. The thermal insulation pipe 150 has thermal insulation properties that can block external heat from being transferred to the inside. In the following embodiment, a case where the thermal insulation pipe 150 is a corrugated pipe 152 will be described.

[0038] The thermally insulated pipe 150 has a corrugated pipe 152 and a thermal insulator 154. The thermal insulator 154 is provided along the outer periphery of the corrugated pipe 152. The thermal insulator 154 may be provided to cover the outer periphery of the corrugated pipe 152.

[0039] The corrugated pipe 152 is a tubular member having a circular tubular cross section in the axial direction, and has circumferential grooves formed in a wave shape on its inner and outer peripheral surfaces. The circumferential grooves on the inner and outer peripheral surfaces of the corrugated pipe 152 may also be formed in an axial spiral shape. The corrugated pipe 152 has an internal space 1521 whose outer edge is the inner peripheral surface of the circular tubular shape. The internal space 1521 can accommodate multiple cable cores 120, and can allow a refrigerant to circulate in one direction during use.

[0040] The superconducting cable 100 does not have any other tubular member inside the corrugated pipe 152 through which a refrigerant flows, which corresponds to a former in a conventional three-phase coaxial cable. That is, the corrugated pipe 152 is a single tubular member that houses multiple cable cores 120 and forms a flow path through which a refrigerant flows. That is, the thermal insulation pipe 150 has a single-pipe structure. It is desirable that the material of the corrugated pipe 152 has a predetermined elasticity at the extremely low temperatures at which the refrigerant is used. In this embodiment, the corrugated pipe 152 is made of a metal, such as stainless steel.

[0041] In superconducting cables having a double-tube structure, such as the conventional superconducting cables described above, the double tube accounts for a significant proportion (e.g., approximately 70%) of the weight of the entire cable. On the other hand, in this embodiment, in which the thermal insulation pipe 150 has a single-tube structure, the weight of the entire cable can be significantly reduced simply by reducing the number of tubular members from two to one. In addition, there is no need to provide a separate large-diameter pipe outside the pipe that forms the internal space for the refrigerant, etc., i.e., the corrugated pipe 152. This allows for a smaller diameter for the thermal insulation pipe 150, and therefore for the entire superconducting cable 200.

[0042] The thermal insulation pipe 150 has a configuration in which a heat insulating material 154 is arranged along the circumferential surface of the corrugated pipe 152. The heat insulating material 154 is preferably made of a material that has insulating properties at the extremely low temperatures at which the refrigerant is used. The heat insulating material 154 prevents heat from penetrating into the corrugated pipe 152 from the outside. The heat insulating material 154 may be, for example, a heat insulating sheet. The heat insulating sheet is made of, for example, an aluminum-deposited polyester film layered with a polyester net or nonwoven fabric. The heat insulating sheet is wrapped around the outer periphery of the corrugated pipe 152 to cover the outer periphery of the corrugated pipe 152. The heat insulating sheet prevents radiant heat from penetrating into the corrugated pipe 152. This configuration allows for insulation suitable for the superconducting cable 100, even with a single-pipe structure. Furthermore, since the heat insulating material 154 is arranged along the circumferential surface of the corrugated pipe 152, reliable insulation is possible.

[0043] In particular, in this embodiment, it is preferable that thermal insulation pipe 150 has a single-pipe structure made up of corrugated pipe 152, and that thermal insulation material 154 is disposed on the outer circumferential side of corrugated pipe 152. In this embodiment, as shown in Fig. 2, thermal insulation material 154 is provided so as to cover the outer circumferential surface of corrugated pipe 152. In this configuration, most of the inside of superconducting cable 100 can be used as a space for the refrigerant, so that a flow path for the refrigerant can be easily secured even if corrugated pipe 152 is made thinner in diameter.

[0044] In the internal space 1521 of the corrugated pipe 152, multiple cable cores 120, each having a superconducting laminated conductor 122, are arranged in a multi-core structure (a three-core structure in this embodiment). By adopting a multi-core structure for the cable core 120 formed using the superconducting laminated conductor 122 as in this embodiment, the overall cable configuration can be simplified compared to the conventional coaxial structure. In this case, the outer diameter of the three cable cores 120 can be significantly smaller than that of the cable cores of conventional superconducting cables in which three layers of superconductors are coaxially arranged. By reducing the diameter of the cable cores 120 in this way, the diameter of the thermal insulation pipe 150 can be significantly reduced, resulting in a significant reduction in the weight of the thermal insulation pipe 150 and therefore the overall weight of the cable. Furthermore, if the thermal insulation pipe 150 has a single-pipe structure, the overall weight of the cable can be further reduced.

[0045] Furthermore, in this embodiment, the conductors constituting each of the plurality of cable cores 120 are laminates (superconducting laminated conductors 122) in which many tape-shaped superconducting wires 1222 are laminated, so the structure is simple.

[0046] That is, according to this embodiment, superconducting cable 100 comprises a thermal insulation pipe 150 having an internal space 1521 through which a refrigerant flows during use, and a plurality of superconducting laminated conductors 122, each of which is a laminate of a plurality of tape-shaped superconducting wires 1222, which are insulated from each other and arranged in a multi-core structure within internal space 1521. As described above, this configuration makes it possible to ensure the ability to carry a large current while simultaneously simplifying the overall cable configuration and reducing its weight.

[0047] As shown in FIG. 2 , in this embodiment, multiple cable cores 120, i.e., multiple superconducting laminated conductors 122, are loosely inserted and housed in a thermal insulation pipe 150. The outer diameter of the multiple cable cores 120 is sufficiently smaller than the inner diameter of the thermal insulation pipe 150, allowing the entire volume of the internal space 1521 other than the cable cores 120 to be used as a refrigerant. This ensures a certain level of refrigerant capacity even when the diameter of the superconducting cable 100 is reduced. Furthermore, because the cable cores 120 are housed with some play, contact between the thermal insulation pipe 150 and the cable cores 120 due to bending of the thermal insulation pipe 150 can be reduced accordingly. This ensures the flexibility and bendability of the superconducting cable 100. This improves the ease of handling of the superconducting cable 100 when it is laid in its intended environment.

[0048] The laminated structure of the tape-shaped superconducting wires 1222 in the superconducting laminated conductor 122 will be described below. FIG. 6A is a diagram schematically showing a cross section of the superconducting laminated conductor 122. The cross section extends along the longitudinal direction of the superconducting laminated conductor 122 and is a plane that cuts the superconducting laminated conductor 122 vertically in the lamination direction. FIG. 6B is a diagram showing the cross section shown in FIG. 6A in a state where multiple tape-shaped superconducting wires 1222 are disassembled from one another. FIG. 7A is a diagram schematically showing longitudinal end portions of the superconducting laminated conductor 122 as viewed from the front side. The longitudinal direction in FIG. 7A corresponds to the direction perpendicular to the plane of the drawing including FIG. 7A. FIG. 7B is a diagram schematically showing a wire-coated tape-shaped superconducting wire 1222-1 in the superconducting laminated conductor 122.

[0049] As shown in Fig. 6A, in the superconducting laminated conductor 122, insulating tapes 126 are provided as insulating layers between the individual tape-shaped superconducting wires 1222 in the lamination direction. This configuration is realized by a configuration shown more specifically in Fig. 6B. As shown in Fig. 6B, in the superconducting laminated conductor 122, wire-covered tape-shaped superconducting wires 1222-1 and wire-exposed tape-shaped superconducting wires 1222-2 are alternately laminated.

[0050] In this embodiment, the insulating tape 126 is spirally wound around the outer circumferential surface, including the front and back surfaces, of the wire-coated tape-shaped superconducting wire 1222-1 (see FIGS. 7A and 7B). When the stacking direction of the tape-shaped superconducting wire 1222 is aligned vertically as shown in FIGS. 6A, 6B, and 7A, the front surface of the tape-shaped superconducting wire 1222 corresponds to the upper surface of the upper half of each of FIGS. 6A, 6B, and 7A. When the stacking direction of the tape-shaped superconducting wire 1222 is aligned vertically as shown in FIGS. 6A, 6B, and 7A, the back surface of the tape-shaped superconducting wire 1222 corresponds to the lower surface of the upper half of each of FIGS. 6A, 6B, and 7A. The lower half of each of FIGS. 6A, 6B, and 7A is upside down, i.e., the back surface of the tape-shaped superconducting wire 1222 corresponds to the upper surface of the lower half, and the front surface of the tape-shaped superconducting wire 1222 corresponds to the lower surface of the lower half. As described above, in the upper half of the superconducting laminate 122, the superconducting layer 1222d of each tape-shaped superconducting wire 1222 is on the upper side (front side) of the substrate 1222b, and in the lower half of the superconducting laminate 122, the superconducting layer 1222d of each tape-shaped superconducting wire 1222 is on the lower side (back side) of the substrate 1222b (see FIG. 4). Therefore, taking the laminate structure shown in FIG. 3 as an example, in each tape-shaped superconducting wire 1222 in the upper half of the superconducting laminate 122 in FIGS. 6A, 6B, and 7A, the stabilization layer 1222f is located on the front side of the strands 1222s, and the stabilization layer 1222a is located on the back side of the strands 1222s. In each tape-shaped superconducting wire 1222 in the lower half of the superconducting laminate 122 in FIGS. 6A, 6B and 7A, a stabilizing layer 1222a is located on the surface of the wires 1222s, and a stabilizing layer 1222f is located on the back of the wires 1222s.

[0051] By wrapping the insulating tape 126 around the outer circumferential surface, an air layer is less likely to form between the insulating tape 126 and the wire 1222s of the wire-coated tape-shaped superconducting wire 1222-1, compared to a laminated configuration in which the insulating tape 126 is simply overlapped on only the front and back surfaces, making it easier to ensure a tight fit.

[0052] Furthermore, from the viewpoint of ensuring stable insulation, it is preferable that the spiral winding of the insulating tape 126 be tightly wound with no gaps in the width direction of the insulating tape 126. Here, it is more preferable that the ratio of the width of the overlapping insulating tape 126 due to the tight winding be 0 to 50%. By overlapping the insulating tape 126 within the range of 0 to 50%, the overlapping of the insulating tape 126 can be limited to two layers rather than three layers, thereby maintaining the thinness and lightness of the superconducting laminate conductor 122. Note that in FIG. 7B , the ratio of the overlapping width W2 of the insulating tape 126 to the width W1 of the insulating tape 126 itself is the ratio of the width of the overlapping insulating tape 126 due to the tight winding. Furthermore, when the ratio of the width of the overlapping insulating tape 126 due to the tight winding is 0%, it means that the wound insulating tapes 126 butt against each other at their side end surfaces.

[0053] As described above, according to this embodiment, the superconducting laminated conductor 122 includes a wire-coated tape-shaped superconducting wire 1222-1 having insulating layers (insulating tapes 126) on the front and back surfaces of the wires 1222s of the tape-shaped superconducting wire 1222, and a wire-exposed tape-shaped superconducting wire 1222-2 having no insulating layers on the front and back surfaces of the wires 1222s of the tape-shaped superconducting wire 1222. The wire-coated tape-shaped superconducting wire 1222-1 and the wire-exposed tape-shaped superconducting wire 1222-2 having no insulating layers on the front and back surfaces are stacked alternately.

[0054] According to this configuration, an insulating layer can be provided between all of the tape-shaped superconducting wires 1222 in the stacking direction without providing an insulating tape 126 for each of the tape-shaped superconducting wires 1222 that make up the superconducting laminate 122. Since the amount of insulating tape 126 used is halved, the weight of the superconducting laminate 122 can be further reduced compared to conventional methods. Since an insulating layer is provided between all of the tape-shaped superconducting wires 1222 in the stacking direction, insulation can also be ensured.

[0055] When the superconducting cable 100 including the superconducting laminated conductor 122 is laid, a longitudinal end of the superconducting laminated conductor 122 (the left end in FIG. 4), i.e., a longitudinal end of the tape-shaped superconducting wire 1222, is connected to the electrode 102 (see FIG. 4). From the viewpoint of ensuring electrical continuity with the electrode 102, it is preferable that the strands 1222s at the longitudinal end of the tape-shaped superconducting wire 1222 are not covered with an insulating layer and are exposed to the outside, as shown in FIG. 8. Therefore, for the strand-covered tape-shaped superconducting wire 1222-1, the wound insulating tape 126 needs to be stripped off at the longitudinal end, for example, during the manufacturing process of the superconducting cable 100. However, in the superconducting laminated conductor 122 according to this embodiment, the strand-covered tape-shaped superconducting wires 1222-1 wound with the insulating tape 126 account for half of all the tape-shaped superconducting wires 1222. Therefore, compared to a configuration in which insulating tape 126 is wrapped around each and every tape-shaped superconducting wire 1222, the ease of work when connecting the superconducting laminated conductor 122 and the electrode 102 can be significantly improved.

[0056] Furthermore, in this embodiment, the outer surface of the insulating tape 126 is smooth, which ensures the sliding properties of adjacent tape-shaped superconducting wires 1222 and prevents localized bending. To ensure the sliding properties of the outer surface of the insulating tape 126, the outer surface of the insulating tape 126 is preferably non-adhesive. The outer surface of the insulating tape 126 refers to the surface of the wire-covered tape-shaped superconducting wire 1222-1 that faces the exposed-wire tape-shaped superconducting wire 1222-2 that overlaps in the stacking direction.

[0057] Incidentally, in order to facilitate the winding of the insulating tape 126 around the wires 1222s of the tape-shaped superconducting wire 1222, it is preferable that the inner surface of the insulating tape 126 facing the wires 1222s to be wound is also non-adhesive.

[0058] Next, the configuration of the superconducting laminated conductor 122 according to Modification 1 of the present embodiment will be described. The configurations of this modification and modifications to be described later are similar to those of the above-described embodiment, and therefore, in each modification, the same reference numerals will be used for the components of the superconducting laminated conductor 122 that are common to the above-described embodiment, and detailed descriptions thereof will be omitted. In describing each modification, differences from the above-described embodiment will be mainly described.

[0059] Fig. 9A is a diagram schematically showing a longitudinal end portion of a superconducting laminate 122 according to Modification 1, viewed from the front side. Fig. 9B is a diagram showing the end portion shown in Fig. 9A in a state where a plurality of tape-shaped superconducting wires 1222 are disassembled from one another.

[0060] In the first modification, the insulating layer is composed of a pair of insulating tapes 126. The pair of insulating tapes 126 are overlapped on the front and back surfaces of the strands 1222s of the tape-shaped superconducting wire 1222 with their longitudinal directions aligned with the front and back surfaces. The strand-covered tape-shaped superconducting wires 1222-1 and the strand-exposed tape-shaped superconducting wires 1222-2 thus configured are alternately stacked. The longitudinal direction corresponds to the direction perpendicular to the plane of the drawing including FIG. 9A or 9B.

[0061] In this configuration, by making the pair of insulating tapes 126 equal in width to the front and back surfaces of the wires 1222s of the tape-shaped superconducting wire 1222, it is possible to reduce the size of the wire-coated tape-shaped superconducting wire 1222-1, and ultimately the size of the superconducting laminated conductor 122.

[0062] In the wire-covered tape-shaped superconducting wire 1222-1, the wires 1222s are reliably integrated with the pair of insulating tapes 126, so that the inner surfaces of the pair of insulating tapes 126 are made adhesive. On the other hand, in order to ensure sliding properties, the outer surface of the insulating tape 126 facing the wire-exposed tape-shaped superconducting wire 1222-2 is made non-adhesive.

[0063] Fig. 10A is a diagram schematically showing a longitudinal end portion of a superconducting laminate 122 according to Modification 2 of the present embodiment, viewed from the front side. Fig. 10B is a diagram schematically showing an insulating tape 126 in the superconducting laminate 122 according to Modification 2, developed into a plane.

[0064] In the second modification, the insulating layer is composed of a single insulating tape 126. The insulating tape 126 is overlapped on the front and back surfaces of the strands 1222s of the tape-shaped superconducting wire 1222 with its longitudinal direction aligned with the front and back surfaces. The strand-covered tape-shaped superconducting wires 1222-1 and the strand-exposed tape-shaped superconducting wires 1222-2 thus configured are alternately stacked. The longitudinal direction corresponds to the direction perpendicular to the paper surface of the drawings including FIG. 10A and corresponds to the up-and-down direction on the paper surface of the drawings including FIG. 10B.

[0065] When a single insulating tape 126 used in this configuration is unfolded in a plane, its width is more than twice the width of the front and back surfaces of the wires 1222s. The main surfaces (outer and inner surfaces) of the insulating tape 126 are divided into a first half 1261 and a second half 1262 with a widthwise center 1260 as the boundary. The insulating tape 126 is folded so that the first half 1261 and the second half 1262 are perpendicular to the widthwise center 1260, with the first half 1261 bonded to one of the front and back surfaces of the wires 1222s, and the second half 1262 bonded to the other of the front and back surfaces of the wires 1222s. Therefore, as shown in FIG. 10A , the insulating tape 126 in the wire-covered tape-shaped superconducting wire 1222-1 has a C-shape or an inverted C-shape when viewed in the longitudinal direction. In this modification, the number of insulating tapes 126 is reduced compared to modification 1, and the number of components of the superconducting laminate 122 can be minimized as in the above embodiment. In this modification, the insulating tape 126 of the wire-sheathed tape-shaped superconducting wire 1222-1 included in the upper half of the superconducting laminate 122 in FIG. 10A is C-shaped. The insulating tape 126 of the wire-sheathed tape-shaped superconducting wire 1222-1 included in the lower half of the superconducting laminate 122 in FIG. 10A is inverted C-shaped. Since the lamination direction is opposite between the upper half and the lower half of the superconducting laminate 122 (see FIG. 4), for example, if each wire-sheathed tape-shaped superconducting wire 1222-1 is manufactured in the same manufacturing process, the C-shape direction will inevitably be opposite between the upper half and the lower half of the superconducting laminate 122. The C-shape of the insulating tape 126 may be oriented in the same direction in the upper half and the lower half of the superconducting laminate 122 .

[0066] In the wire-covered tape-shaped superconducting wire 1222-1, the inner surface of the insulating tape 126 is made adhesive to reliably integrate the wires 1222s with the insulating tape 126. On the other hand, to ensure sliding properties, it is preferable that the outer surface of the insulating tape 126 facing the wire-exposed tape-shaped superconducting wire 1222-2 is made non-adhesive.

[0067] FIG. 11 is a diagram showing a schematic view of a longitudinal end portion of a superconducting laminate 122 according to a third modification of this embodiment, viewed from the front side.

[0068] In the third modification, the insulating layer is composed of a pair of insulating tapes 126. The insulating tapes 126 are overlapped on the front and back surfaces of the strands 1222s of the tape-shaped superconducting wire 1222 with their longitudinal directions aligned with the front and back surfaces. The strand-covered tape-shaped superconducting wires 1222-1 and the strand-exposed tape-shaped superconducting wires 1222-2 thus configured are alternately stacked. The longitudinal direction corresponds to the direction perpendicular to the plane of the drawing including FIG. 11.

[0069] The pair of insulating tapes 126 used in this configuration have widths wider than the widths of the front and back surfaces of the wires 1222s. Therefore, when the pair of insulating tapes 126 are placed on the front and back surfaces of the wires 1222s, widthwise ends 1263 of each insulating tape 126 protrude from the front and back surfaces of the wires 1222s on both sides in the width direction. The pair of insulating tapes 126 are adhered to each other at the widthwise ends 1263, thereby integrating the pair of insulating tapes 126 and the wires 1222s.

[0070] In this configuration, there is no need to align the positions of the widthwise ends 1263 of the insulating tape 126 with the positions of the widthwise ends of the wires 1222s, which has the advantage of allowing a high degree of freedom in setting the dimensions of the insulating tape 126.

[0071] In order to bond the pair of insulating tapes 126 together, the inner surface of at least one of the insulating tapes 126 is made adhesive. On the other hand, it is preferable that the outer surfaces of both insulating tapes 126 are made non-adhesive to ensure slidability.

[0072] Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the specific embodiments described above. Various modifications and changes to the specific examples described in the above embodiments are possible within the scope of the gist of the present invention as defined in the claims. [Industrial Applicability]

[0073] The superconducting laminated conductor according to the present invention can be suitably used as a superconducting cable. [Explanation of symbols]

[0074] 1 Electric propulsion system 11 Turbine 12 Fuel tank 13, 17 Output shaft 14 Superconducting generator 15 inverter 16 Superconducting motor 18 propellers 19 Cooling System 20, 21 Power transmission cables 100 Superconducting Cable 102 electrode 120 cable core 122 Superconducting laminated conductor 122U top surface 122L Bottom surface 1222 Tape-shaped superconducting wire 1222a, 1222f stabilization layer 1222b board 1222c middle layer 1222d superconducting layer 1222e protective layer 1222s bare wire 1222-1 Superconducting wire with coated wire tape 1222-2 Exposed wire type superconducting wire tape 124 Interphase insulation sheet 126 Insulating Tape 1260 Width center part 1261 First half 1262 Second half 1263 Width end 127 Gap 150 Insulated pipe 152 Corrugated pipe 1521 Interior Space 154 Insulation

Claims

1. A superconducting laminated conductor formed by laminating a plurality of tape-shaped superconducting wires, The plurality of tape-shaped superconducting wires are a wire-coated tape-shaped superconducting wire having insulating layers on the front and back surfaces of the wire; a wire-exposed tape-shaped superconducting wire having no insulating layer on the front and back surfaces of the wire, The wire-covered tape-shaped superconducting wire and the wire-exposed tape-shaped superconducting wire are alternately stacked. Superconducting laminated conductor.

2. the insulating layer is formed of an insulating tape wound around an outer peripheral surface including the front surface and the back surface or superimposed on the front surface and the back surface, In the wire-covered type tape-shaped superconducting wire, an outer surface of the insulating tape facing the wire-exposed type tape-shaped superconducting wire adjacent in the stacking direction is non-adhesive. The superconducting laminated conductor according to claim 1 .

3. the insulating tape is wound spirally around the outer circumferential surface including the front surface and the back surface, The spiral winding of the insulating tape is densely wound with no gaps in the width direction of the insulating tape, and the ratio of overlapping widths of the insulating tape due to the dense winding is 0% to 50%. The superconducting laminated conductor according to claim 2.

4. the insulating layer is formed by a pair of insulating tapes respectively overlapping the front surface and the back surface with their longitudinal directions aligned with the front surface and the back surface, The pair of insulating tapes have the same width as the front and back surfaces. The superconducting laminated conductor according to claim 1 .

5. the insulating layer is formed by a single piece of insulating tape superimposed on the front surface and the back surface with the longitudinal direction aligned with the front surface and the back surface, the insulating tape is divided into two halves at a central portion in the width direction, and the two halves are overlapped on the front surface and the back surface, respectively; The superconducting laminated conductor according to claim 1 .

6. the insulating layer is formed by a pair of insulating tapes superimposed on the front surface and the back surface with their longitudinal directions aligned with each other, The pair of insulating tapes are each wider than the front surface and the back surface, and when the pair of insulating tapes are overlapped on the front surface and the back surface, both end portions thereof protruding in the width direction are adhered to each other. The superconducting laminated conductor according to claim 1 .

7. A superconducting laminated conductor according to claim 1, The device further includes a thermal insulation pipe having an internal space through which a refrigerant flows during use, and in which a plurality of the superconducting laminated conductors are insulated from each other and arranged in a multi-core structure within the internal space. Superconducting cable.

8. An electric propulsion system mounted on a transportation device, A power generating system comprising the superconducting cable according to claim 7, a power source, and an electric motor, the superconducting cable connects the power source and the electric motor; supplying electric power via the superconducting cable to drive the electric motor and propel the transportation equipment; Electric propulsion system.

9. The transportation device is an air vehicle. The electric propulsion system of claim 8.

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