Superconducting cable comprising solder channel

Abstract

Techniques are described that allow for easier, faster solder filling of HTS cables and reduce performance degradation of HTS in the cables. In particular, in addition to a secondary channel providing an increased hydraulic cross-section through which solder can flow, channels within the HTS cable may include a primary channel in which the HTS is disposed. The secondary channel may be connected to the primary channel (e.g., as a side channel). If the secondary channel has a smaller opening within the primary channel than the HTS material disposed in the primary channel, the HTS material does not have a risk of moving into the secondary channel, which may provide a space proximate to the HTS material and the primary channel, through which solder may freely flow.

Description

Background Art

[0001] A superconductor is a material that has no resistance to electric current (is "superconducting") at a certain critical temperature. For many superconductors, the critical temperature is below 30°K, making the operation of these materials in the superconducting state require significant cooling, which is carried out, for example, using liquid helium.

[0002] Since superconductors can carry high currents without resistance, high-field magnets are typically constructed from superconductors. Such magnets can, for example, carry a current greater than 5 kA. Summary of the Invention

[0003] In some aspects, the structures and techniques described herein relate to a cable that includes: a conductive structure extending along the cable and including a channel, the channel including a main channel portion and a side channel portion connected to the main channel portion and disposed beside the main channel portion; a high-temperature superconductor (HTS) tape stack (or laminate) disposed within the main channel portion of the channel; and solder disposed within the side channel portion of the channel and at least a portion of the main channel portion of the channel.

[0004] In some aspects, the techniques described herein relate to a method that includes: at least partially filling a channel of a high-temperature superconductor (HTS) cable assembly with molten metal, the HTS cable assembly including: a conductive structure extending along the HTS cable assembly and including the channel, the channel including a main channel portion and a side channel portion connected to the main channel portion and disposed beside the main channel portion; and an HTS tape stack disposed within the main channel portion of the channel, wherein at least partially filling the channel of the HTS cable assembly includes directing the molten metal into the side channel portion of the channel and into the main channel portion of the channel. In an embodiment, the method further includes operating one or more cooling devices to cool the molten metal in one or both of the side channel portion or the main channel portion.

[0005] In some aspects, the techniques described herein relate to a cable that includes: a conductive structure extending along the cable and including a channel, the channel including a main channel portion and a secondary portion; a high-temperature superconductor (HTS) tape stack disposed within the main channel portion of the channel; and solder disposed within the secondary portion of the channel and at least a portion of the main channel portion of the channel.

[0006] In some aspects, the techniques described herein relate to a cable that includes: a conductive structure extending along the cable and including a channel, the channel including a main channel portion; a sheath structure disposed at least partially around the conductive structure, the sheath structure including a side channel portion connected to and disposed beside the main channel portion of the conductive structure; a high temperature superconductor (HTS) tape stack disposed within the main channel portion of the channel; and solder disposed within the side channel portion of the sheath structure and at least a portion of the main channel portion of the channel.

[0007] In some aspects, an HTS cable assembly includes: at least one conductive structure extending along the cable and including a main channel portion and a side channel portion, having an opening therebetween such that the main channel portion and the side channel portion are in fluid communication; and a high temperature superconductor (HTS) tape stack disposed within the main channel portion, wherein at least a portion of the HTS tape stack is adjacent (or proximate) to the opening between the main channel portion and the side channel portion.

[0008] In an embodiment, the size of the opening between the main channel portion and the side channel portion is selected such that the HTS tape stack does not move into the side channel.

[0009] In an embodiment, the HTS cable assembly may further include a metal sheath disposed around the conductive structure.

[0010] In an embodiment, the HTS cable assembly includes a plurality of conductive structures, each corresponding to a conductive section, each of the plurality of conductive sections having a shape that defines a main channel portion and a side channel portion, and each of the main channel portions having an HTS tape stack disposed therein.

[0011] In an embodiment, the HTS cable assembly may further include an insulator disposed between adjacent conductive sections of the plurality of conductive sections, the insulator sized and shaped such that the plurality of conductive sections are electrically insulated from each other.

[0012] In an embodiment, the plurality of conductive sections in the HTS cable assembly are disposed around a central longitudinal axis of the HTS cable assembly; and the HTS tape stack follows a helical path around the central longitudinal axis of the HTS cable assembly.

[0013] In an embodiment, the HTS cable assembly may further include an electrically insulating material disposed between adjacent conductive sections of the plurality of conductive sections, the electrically insulating material causing the plurality of conductive sections to be electrically insulated from each other.

[0014] The foregoing device and method embodiments can be implemented using any suitable combination of aspects, features, and acts (or actions, steps) described in further detail above or below. These and other aspects, embodiments, and features of the present teachings can be more fully understood from the following description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Aspects and embodiments will be described with reference to the following drawings. It should be understood that the drawings are not necessarily to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For clarity, each component may not be labeled in every figure.

[0016] Figure 1 A cross-sectional view of an illustrative superconducting cable according to some embodiments is shown;

[0017] Figures 2A to 2D Each depicts a conductive section separate from the cable according to some embodiments, where the conductive section may be disposed in the cable;

[0018] Figure 3 A cross-sectional view of an illustrative superconducting cable including a sheath according to some embodiments is shown;

[0019] Figures 4A to 4B is a flowchart of a method of metal-filled superconducting cable according to some embodiments;

[0020] Figure 5 is a block diagram of a cooling system including one or more movable blowers and one or more heaters, where a first heater is configured to be in thermal contact with a first end of the HTS cable and a second heater is configured to be in thermal contact with an opposite second end of the HTS cable; and

[0021] Figure 6 is a perspective view of a fusion (or fusing) machine according to some embodiments, with a portion of the fusion machine removed (with a locally excised portion) to illustrate various internal components of the fusion machine. DETAILED DESCRIPTION

[0022] High-field superconducting magnets typically include a plurality of electrically insulated cable turns grouped in a multi-layer arrangement. When the superconducting material is cold enough to be below its critical temperature (the temperature below which the resistivity of the material drops to zero), driving the magnet allows current to pass through the superconducting path without loss. However, for various reasons, some or all of the superconducting material may be heated above its critical temperature and thus lose its superconducting properties. If uncontrolled, this heating can cause the superconductor to lose its superconducting ability, commonly referred to as a "quench". Additionally, if the system does not properly address the quench (e.g., by shutting down), components may be damaged by heating.

[0023] Some superconducting magnet systems process quench events via an active alarm and detection mechanism system. Other superconducting magnet systems passively handle quenches through the design of the superconducting magnet itself. An example of the latter scheme is a non-insulated (NI) magnet (also known as a no-insulation (NI) magnet), where adjacent superconducting turns of the magnet are not insulated from each other, but are separated by a conventional conductor (i.e., a non-superconductor). When the magnet operates below the critical temperature of the superconductor, current flows through the superconductor without flowing across the turns, because the superconductor has zero resistance compared to the finite resistance of the conductor located between the turns.

[0024] Some designs of superconducting cables can include high-temperature superconductor (HTS) materials disposed within a conductive structure. For example, the cable can include a conductive structure that supports one or more HTS tapes. The conductive structure (sometimes referred to as a "former") can include a plurality of channels in which the HTS tapes are disposed. However, such an arrangement may result in a small gap between the HTS and the former, which may reduce the current-carrying capacity of the cable and may increase the cable's sensitivity to quenches. The cable can be insulated or can be placed in a conductive support structure to create a non-insulated magnet.

[0025] In a so-called vacuum pressure impregnation (VPI) process, one or more HTS magnet structures (e.g., HTS materials disposed within a conductive structure) are heated, and molten solder enters and passes through open channels in the structure. The solder can flow into open spaces in the magnet structure and fill them with a conductive material. In some cases, the process can be performed at a relatively low temperature (e.g., about 200 °C) to allow the solder to flow through the structure.

[0026] Exposure to molten solder may erode or otherwise damage the HTS tapes. For example, exposure to molten solder may erode the protective copper cladding around the HTS tapes. Therefore, in some cases, it may be desirable to reduce the duration of contact between the molten solder and the HTS during the VPI process. Additionally, due to the open spaces within the cable around the twisted HTS material, it may be difficult to efficiently fill a twisted HTS cable prior to the VPI process because such spaces may be small relative to the cable diameter. In some cases, relatively small spaces may be blocked, hindering solder flow.

[0027] Compared to prior art, the techniques described herein allow for easier and faster solder filling of HTS cables and reduce the degradation of the performance of the HTS in the cable.

[0028] In particular, in addition to providing sub-channels that provide an increased hydraulic cross-section through which solder can flow, the channels within the HTS cable can include a main channel in which the HTS is disposed. The sub-channels can be connected to the main channel (e.g., as side channels). If the sub-channels are connected to the main channel via an opening that is smaller than the HTS material disposed in the main channel, there is no risk of the HTS material moving into the sub-channels, which can provide a space adjacent (or proximate) to the HTS material and the main channel through which the solder can flow freely.

[0029] As a result, compared to prior structures and techniques, the molten solder can enable more efficient and thus much less time to flow into the desired space within the cable. Due to this efficiency improvement (e.g., improvement in flow rate), the HTS cable can be manufactured at a given degradation level that is smaller than the degradation levels achieved using prior art, where in the prior art, the HTS cable structure does not include a main channel and sub-channels. Additionally, as a result of the efficiency improvement achieved using the structures and techniques described herein, much longer HTS cables can be manufactured at a given degradation level (compared to existing solutions), because the increased flow rate means that a longer flow distance can result in the same amount of degradation of the HTS material during the solder flow process.

[0030] Figure 1 A cross-sectional view of an illustrative superconducting cable in accordance with some embodiments is shown. Although the techniques described herein can be applied to any suitable superconducting cable, Figure 1 an example of a cable is depicted in which three HTS-containing channels are formed in three separate conductive segments 112 that are separated from each other by electrical insulation material 116. The following description can apply equally, for example, to cables in which any number of channels are disposed within a single conductive structure (e.g., having a circular cross-section).

[0031] In Figure 1 the example, the conductive segments 112 are configured to hold corresponding HTS tape stacks 111 within corresponding channels in each segment. It can be noted that the cable 110 can be produced from multiple instances (here three instances) of the same conductive segments 112 arranged as Figure 1 shown. Figure 1 The illustrative cable of 40 50 or a combination thereof, or can be composed of steel, 40 50 or a combination thereof.

[0032] In Figure 1In the example, the HTS tape stack 111 is disposed in contact with the solder 115, and the solder 115 provides at least partial electrical contact between the HTS tape stack and each corresponding conductive section 112. The solder 115 may include any suitable material. For example, the solder 115 may include (lead) Pb and / or (tin) Sn solder or may consist of (lead) Pb and / or (tin) Sn solder. In some embodiments, the solder 115 may include a metal having a melting point of less than 200 °C, wherein at least 50% (50 wt%) of the metal by weight is Pb and / or Sn.

[0033] As Figure 1 shown in the example, the channels formed within each conductive section 112 in which the HTS tape stack 111 and the solder 115 are disposed include a larger main channel portion that holds the HTS tape stack (sometimes also referred to herein as the "main portion", i.e., the HTS tape stack 111 is disposed in the corresponding main channel portion), and a smaller secondary portion 117 on the side of the main portion (sometimes also referred to herein as the "side channel portion" or "secondary portion" or "secondary channel"). In Figure 1 the example, the main channel portion and the side channel portion are in fluid communication (e.g., coupled or connected).

[0034] As described above, the secondary portion of the channel may provide a passage or path for the solder 115 to pass through during the process of filling the cable with solder. As shown, the solder may also be deposited or otherwise disposed along the sides and / or top of the HTS stack. The solder in the main portion and the secondary portion of the channel may together form a continuous solder region.

[0035] It should be noted that in the absence of the secondary portion of the channel, the space through which the solder must pass may be limited. Thus, including the secondary portion can increase the hydraulic cross-section for solder flow. Therefore, compared to the time required for solder filling when the channel does not include a secondary portion, including a secondary portion (e.g., secondary portion 117) in the channel can reduce the amount of time required for solder filling. This may be at least partially attributed to the smaller hydraulic cross-section for solder flow in a channel that does not include a secondary portion compared to the hydraulic cross-section for solder flow in a channel that includes a secondary portion. When filling the main portion and the secondary portion of the channel, the channel may include a continuous solder region disposed (and preferably fully filled) within both the main portion and the secondary portion of the channel.

[0036] Therefore, compared to the solder filling time of a superconducting cable including a channel having a secondary portion, omitting the secondary portion may result in an increase in the solder filling time. Due to the thermal exposure during filling, a longer solder filling time may lead to degradation (or increased degradation) of the HTS material. Thus, due to the thermal exposure during filling, including the secondary portion can result in less (and ideally minimal or no) degradation of the HTS material.

[0037] As described above, the opening between the main portion and the secondary portion 117 of the channel can be smaller than the HTS tape stack 111. Although the secondary portion 117 is shown in Figure 1 as being at the bottom of the main portion, it should be understood that the secondary portion 117 can be located along any region of the main portion (including but not limited to the middle or top region of the main portion).

[0038] During operation of the cable 110, at least the HTS tape stacks 111 are cooled below their superconducting transition (temperature) so that they can carry current at zero resistance. The conductive sections 112 act as stabilizers during a quench; when a portion of the HTS material quenches, heat can be conducted through the conductive sections that support the quenched superconducting components to other conductive sections, thereby across the entire cross-section of the quench cable. Subsequently, non-superconducting regions can be created within the HTS tape stacks 111 and propagated along the cable.

[0039] According to some embodiments, the conductive section 112 can comprise or can be composed of copper. Copper can be a desirable material due to its high thermal conductivity, thus providing a stabilizing function in the case of a quench and being electrically conductive. Other suitable materials for the conductive section 112 can include aluminum, or can be composed of aluminum.

[0040] According to some embodiments, the electrical insulating material 116 is arranged to contact different conductive sections 112 on either side. As Figure 1 shown, the electrical insulating material 116 is arranged between adjacent pairs of conductive sections 112 and can be arranged to contact both sections of the pair (ideally so that there is no gap or substantially no gap between the electrical insulating material 116 and each conductive section). In some embodiments, the electrical insulating material 116 can be provided in the form of a tape that can be arranged between pairs of conductive sections 112. In some cases, the tape can be an adhesive tape (or sticky tape) and is adhered to the adjacent conductive sections 112 via an adhesive, such that the tape is adhered to the conductive sections.

[0041] According to some embodiments, the HTS tape stack 111 can include one or more high-temperature superconductors. As used herein, "high-temperature superconductor" or "HTS" refers to a material having a critical temperature above 30°K, where the critical temperature is the temperature below which the resistivity of the material is zero. In some cases, the critical temperature can depend on other factors, such as the presence of an electromagnetic field. It should be understood that when referring to the critical temperature of a material herein, this can refer to the critical temperature that happens to pertain to the material under the given conditions.

[0042] The HTS tape stack 111 can include one or more length segments of HTS tape, which is a long, thin strand of HTS material having cross-sectional dimensions of a thickness (or height) in the range of about 0.001 mm to about 0.1 mm and a width in the range of about 1 mm to about 12 mm (and having a length extending along the length of the cable, i.e., in the direction of the length of the page in the example shown). In some embodiments, the HTS tape can include polycrystalline HTS and / or can have a high level of grain alignment. The HTS tape stack 111 can include a plurality of HTS tapes stacked on top of each other in the width direction and the length direction. The HTS tape stack can thus have a thickness equal to (or approximately equal to) the thickness of a single tape multiplied by the number of tapes in the (tape) stack. Figure 1 In some embodiments, the electrical insulating material 116 can include polyimide (e.g.,

[0043] ), epoxy resin, phenolic resin, plastic, elastomer, steel (e.g., stainless steel), or a combination thereof. According to some embodiments, the insulating material can have a breakdown voltage or dielectric strength greater than 25 kV / mm, greater than 50 kV / mm, greater than 75 kV / mm, greater than 1000 kV / mm. In some embodiments, the electrical insulating material 116 can include a high resistivity material or can be composed of a high resistivity material, which is still conductive to some extent. In this regard, referring to material 116 as "insulating" refers to the fact that material 116 is much less conductive than the material constituting the conductive section 112. For example, in some embodiments, the conductive section 112 can include a highly conductive material such as copper, while the electrical insulating material 116 can include steel, which is not strictly an insulator but is still much more insulating than copper.

[0044] In the example shown, in addition to the advantages regarding quench behavior described above, the conductive section 112 can also provide mechanical integrity to the cable. The conductive section 112 can be formed into or can conform to a desired shape and can provide a significant (or substantial) amount of structural strength to the cable. This is in contrast to other superconducting cables, such as cable-in-conduit conductors (CICC) braided cables, which are characterized by twisted copper rods that can deform under high electromagnetic loads.

[0045] In Figure 1 the example shown, in addition to the advantages regarding quench behavior described above, the conductive section 112 can also provide mechanical integrity to the cable. The conductive section 112 can be formed into or can conform to a desired shape and can provide a significant (or substantial) amount of structural strength to the cable. This is in contrast to other superconducting cables, such as cable-in-conduit conductors (CICC) braided cables, which are characterized by twisted copper rods that can deform under high electromagnetic loads.

[0046] According to some embodiments, the conductive section 112 can be twisted (or stranded) along the length of the cable 110. That is, the conductive section 112 can be twisted around the central longitudinal axis of the cable; thus, in addition to the rotational orientation of the view shown (which will rotate around the center of the cable as the cross-sectional view moves along the length of the cable), Figure 1The cross-sectional view may be accurate at various points along the cable. The helical path is an example of a twisted path that a conductive section can follow around the central longitudinal axis of the cable. In such a configuration, the conductive sections 112 can be aligned along corresponding helical paths, where the center of each helix is the central longitudinal axis of the cable. Similarly, the HTS tape stacks 111 can be supported by the conductive sections 112 along the length of the cable in the manner shown, and thus are also aligned along corresponding helical paths, where the center of each helix is the central longitudinal axis of the cable. Arranging the HTS tape stacks 111 along the twisted path can reduce the length over which the two conductive paths are parallel to each other, and thus reduce this source of inductive heating. Figure 1 The HTS tape stacks 111 are supported by the conductive sections 112 along the length of the cable in the manner shown and are thus also aligned along corresponding helical paths, where the center of each helix is the central longitudinal axis of the cable. Arranging the HTS tape stacks 111 along the twisted path can reduce the length over which the two conductive paths are parallel to each other, and thus reduce this source of inductive heating.

[0047] In Figure 1 the example of, the cable 110 includes a central cooling channel 118, which can be a tubular cooling channel extending along the longitudinal axis of the cable. Generally, any number of channels can be formed through or otherwise provided in the cable to provide cooling to the conductive sections 112 and / or to the HTS tape stacks 111. Such cooling channels can provide, for example, a path for cryogenic liquids (such as liquid helium or liquid nitrogen) to flow and carry heat away from the conductive sections 112 and / or the HTS tape stacks 111. The coolant can be provided through the cooling channels at a high pressure (such as above 2 bar).

[0048] Figures 2A to 2D Each depicts a conductive section separate from the cable according to some embodiments, where the conductive section can be arranged in the cable. For example, Figure 2A the conductive section 212 shown in includes a channel that contains a main region (or main channel portion) 215 and a secondary region (or side channel portion) 216, corresponding to Figure 1 the conductive section 112 shown in. The secondary region 216 is recessed and has a semi-circular cross-sectional shape.

[0049] As described above, a superconducting cable can include any number of such sections with insulating material disposed between the sections. In some embodiments, a superconducting cable can include a plurality of sections arranged such that the sections exhibit radial symmetry about the central axis of the cable. Alternatively, a superconducting cable can include a single conductive structure that includes a plurality of channels, each channel having Figures 2A to 2D any one or more of the channel shapes shown in.

[0050] In Figure 2B the example of, the conductive section 222 includes a channel that contains a main region (or main channel portion) 225 and secondary regions (or side channel portions) 226 and 227, where the secondary regions (or side channel portions) 226 and 227 are wedge-shaped (or "flared") regions disposed on either side of the main region. InFigure 2C In the example of, the conductive segment 232 includes a channel that contains a main region (or main channel portion) 235 and a secondary region (or side channel portion) 236. The secondary region (or side channel portion) 236 is a wedge-shaped (or "flared") region disposed next to the main region at the perimeter of the segment.

[0051] In Figure 2D the example of, the conductive segment 242 includes a first channel (or main channel portion) 245 and a second channel (or side channel portion) 246. The first channel (or main channel portion) 245 and the second channel (or side channel portion) 246 are not formed as a continuous channel, but rather as separate channels within the segment. This solution may have the advantage of reducing the potential impact of the larger channel on the strength of the segment, but may also have the disadvantage that the solder is filled farther from the HTS material and may not easily fill the space.

[0052] As an alternative to the above solution, when the formed part is disposed within the sheath structure, the secondary region (also referred to as the side channel portion) of the channel can be formed on top of the main channel portion. This solution is shown in Figure 3 where a cross-sectional view of a superconducting cable 300 is shown. In Figure 3 the example of, the cable includes a single conductive structure 312 in which a main portion of three channels is formed. The secondary portions of these channels are formed in the sheath structure 321. For example, a main portion 316 of one channel is formed in the conductive structure 312, and the secondary portion 317 is formed within the sheath structure 321.

[0053] In Figure 3 the example of, the sheath structure 321 can be, for example, a stainless steel sheath that is wrapped in a dielectric layer 323 (e.g., a polyimide layer, fiberglass cloth such as ).

[0054] In some embodiments, the cable assembly can be wrapped in a dielectric (e.g., fiberglass cloth, polyimide) and then vacuum pressure impregnated to fill the residual space between the cable turns with a dielectric such as epoxy resin. For example, the cable assembly can be wrapped in a first dielectric arranged in multiple turns (multi-turns) and then vacuum pressure impregnated with epoxy resin. The epoxy resin can be cured by heat (or a heat device) or otherwise.

[0055] In some embodiments, the cable assembly can be disposed within a structural matrix. For example, the sheath can include multiple channels in which windings of the cable assembly (or windings of multiple cable assemblies) can be disposed. Thus, the sheath can serve as a structural support (e.g., a structural plate) for supporting multiple windings of one or more cable assemblies. In some embodiments, such a sheath can be surrounded by one or more dielectric layers as described above.

[0056] Figures 4A to 4B is a flowchart of a method of metal-filled superconducting cable according to some embodiments. It should be understood that, unless explicitly stated, the processing actions in the flowchart are non-sequential, which means that the processing actions listed in the flowchart can be executed in any convenient order.

[0057] Now refer to Figure 4A 、 Figure 4B , an illustrative process for filling an HTS cable (e.g., any cable described herein) with a metal (e.g., solder) begins in act (or step) 401 by cleaning one or more components of the cable that will undergo the metal filling process (e.g., any of the above components, such as one or more channels of a conductive structure, one or more channels of one or more conductive segments, channels within a former, HTS material, sheath, fitting, or combinations thereof). In some embodiments, act 401 includes cleaning the one or more cable components by flushing the components with an acidic solution and then rinsing the components with water and / or another liquid. Details of illustrative examples of such processes are described below.

[0058] Hereinafter, for convenience, the material used for filling is generally referred to as "metal", although the material need not be a pure metal and can be, for example, a metal alloy. Thus, in the following description, references to "metal" used in the method should be understood to also cover metal alloys.

[0059] As a non-limiting example of cleaning one or more components of a cable, a reservoir containing a mixture of water and a cleaning solution (e.g., Citronox acid cleaner) is coupled (or connected) to the cable former, and the water / cleaning solution mixture is pumped or otherwise conveyed from the reservoir through the cable former. Subsequently, a rinse fluid (e.g., clean water) is pumped through the cable former to flush the water / cleaning solution mixture out of the cable former. In some cases, the water / cleaning solution mixture and / or the rinse liquid can be heated to above room temperature (e.g., heated to 140°F).

[0060] After cleaning the components in act 401, the HTS material is disposed in one or more channels of the conductive structure and / or one or more channels of one or more conductive segments in act 402, thereby creating the HTS arrangement as described above (e.g., as Figure 1Arrangement of the HTS tape stacks 111 within the conductive section 112 shown). In some embodiments, the HTS material arranged in one or more channels in act 402 may include one or more stacks of HTS tapes. In some embodiments, the HTS tape stacks may be pre-tinned to ensure good bonding between the tapes (e.g., a bond where the tapes are firmly coupled together). In some embodiments, the metal that will be used to fill the cable may be utilized to pre-tin the HTS tape stacks. In some embodiments, the HTS tapes are pre-coated with lead-tin (PbSn) solder (or a lead-tin solder alloy).

[0061] In act 403, a so-called "loose HTS cable assembly" (or more simply referred to as an "HTS cable assembly") is formed. The HTS cable assembly is sometimes referred to as a "loose cable assembly" because at least the HTS material (and possibly other components) has not yet been structurally fixed to a channel or other structure that forms part of the HTS cable.

[0062] As used herein, an "HTS cable assembly" or a "loose HTS cable assembly" may refer to a cable structure that includes HTS material (e.g., HTS tapes), examples of which are provided herein. For example, one type of HTS cable assembly includes HTS material disposed within a channel of a former, which may have optional additional fittings and the like. In some embodiments, the HTS cable assembly may include HTS tapes disposed at the bottom of the channel. Although in the above illustrative embodiment, the cable former is shown as having a circular cross-sectional shape, in other embodiments, the former may be provided with a different cross-sectional shape (e.g., an oval cross-sectional shape, a rectangular cross-sectional shape, a square cross-sectional shape, or any regular or irregular geometric cross-sectional shape).

[0063] At any point before or after the HTS material is disposed in the HTS cable assembly (e.g., after the HTS material is disposed in the channel of a former or other structure), the HTS cable assembly may be bent into a desired shape (e.g., a coil, a circle, a loop, or a multi-loop shape).

[0064] Back to Figure 4A, in act 404, flux is optionally applied to some or all of the HTS material and / or cable components that will form the HTS cable to remove any oxidation on the surface of the HTS material and / or cable components. In some embodiments, the liquid flux may be applied shortly before soldering. Desirably, the flux permeates all surfaces of the cable components that will be exposed to the molten metal in a manner similar to the subsequent flow of the molten metal described below. In some embodiments, it has been found that the application of the liquid flux enables good wetting of the solder to the tape and cable. In some embodiments, act 404 may include applying an RMA-5 liquid flux (Indium Corp) and / or Select-10 Flux (Kester) having a lower resin content and corrosiveness. However, it should be understood that other liquid fluxes having the same or similar properties as the RMA-5 liquid flux may also be applied in act 404.

[0065] In act 405, the HTS cable assembly is then evacuated (or emptied) (e.g., by placing the HTS cable assembly in a chamber and evacuating the chamber) and purged with a gas such as an inert gas. In embodiments where flux is applied in act 404, any excess flux (e.g., flux that does not adhere to the HTS material or components) may be discharged from the components due to the evacuation in act 405. However, it has been found that any residual flux can be effectively flushed by the flow of the heavier molten metal solder (which will be described in conjunction with act 409). Thus, depending on how much flux remains in the assembly, an explicit step of discharging excess flux may not be required. In embodiments having a long and complex cable geometry, pressurization may be used to discharge the excess flux. After applying the flux (if used), the cable assembly is evacuated again and purged with an inert gas to remove oxygen, which would interfere with the effective action of the flux when heated.

[0066] In act 406, the HTS cable assembly is heated to a first temperature. In cases where pure metal is used for Figures 4A to 4B the metal filling process, the first temperature may be selected to be below the melting temperature of the metal. In cases where a metal alloy is used for Figures 4A to 4B the metal filling process, the first temperature may be selected to be below the liquidus temperature of the metal alloy.

[0067] In some embodiments, act 406 can include heating the HTS cable assembly, along with any associated fittings and tubing, within a furnace (such as a convection furnace). This type of heating can provide a certain degree of uniformity with a reduced (ideally minimal) required external temperature control, and importantly, reduce (ideally avoid) the risk of the HTS tape temperature exceeding the furnace set point and the degradation of that portion of the HTS tape (and that portion of the cable) due to exposure to undesired temperatures.

[0068] Before, after, or simultaneously with heating the cable assembly in act 406, the metal filling the HTS cable assembly is melted into a liquid state (or a solid / liquid state in the case of an alloy) in act 407. A temperature-controlled heater in a container (sometimes also referred to herein as a pot or crucible) can be used to melt the metal, for example. Thermocouples inside and / or outside the pot can be used to determine when the melting process is complete and the temperature of the molten metal before it flows. In some embodiments, the metal can be melted within the furnace where the cable is located, but in other embodiments, the metal can be melted independently (e.g., outside the furnace). The HTS cable assembly is then heated to the temperature at which the metal will flow in act 408.

[0069] One aspect of the metal filling process that has been found to be important is obtaining a desired time-temperature profile. The temperature needs to be high enough to make the metal a fluid with low viscosity, but result in a low enough exposure to avoid thermal degradation, as well as degradation due to the chemical effects of the metal on the HTS material (e.g., rare-earth barium copper oxide (REBCO) tape stack).

[0070] In some embodiments for solder filling of HTS cables using a tin-lead (PbSn) solder, two steps can be performed, where the HTS cable includes an HTS tape stack, and the HTS tape stack includes multiple layers of REBCO tapes. First, the furnace is set to a temperature that heats the HTS cable assembly but does not degrade (or substantially degrade) the HTS tapes. In some embodiments, the furnace can be set to a temperature below the melting point of the solder disposed on the HTS tapes (e.g., when the process is filling the cable with PbSn solder, the furnace can be set to heat to 185 °C), thereby greatly reducing and ideally avoiding degradation of the HTS tape stack. The heating process continues until the temperature of the entire cable (or more appropriately, the cable assembly) has reached the set temperature of the furnace. The furnace set temperature is maintained at this temperature until the solder source (e.g., the solder source in the can) is completely melted and equilibrated to a processing (or process / technology) temperature of about 200 °C. Second, then the furnace temperature can be set to a temperature that achieves the desired flow temperature of the solder. In embodiments employing PbSn solder, the furnace temperature can be set to a temperature of about 205 °C, and a waiting period occurs until all points on the cable and any associated conduits required for the metal filling process reach the desired flow temperature (e.g., in the case of PbSn solder, a flow temperature of about 200 °C), and temperature monitoring is performed to ensure that no point on the HTS cable assembly exceeds a temperature of about 200 °C. In some embodiments, a dwell period can be performed at an intermediate temperature such as about 194 °C. This scheme reduces and ideally avoids degradation of the superconducting properties of the HTS tape stack. Once these temperature conditions are met, the metal flow process begins in act 409, and preferably begins rapidly in order to reduce and ideally minimize the amount of time the HTS tape stack is exposed to this relatively high temperature (e.g., a temperature above or about 200 °C).

[0071] Applying and monitoring multiple temperature monitoring devices (e.g., thermocouples) at multiple points on the metal filling processing station and on the cable can be important for this process because the degradation of some HTS materials (e.g., REBCO) increases exponentially with temperatures above 200 °C. The location of the temperature monitoring devices is selected for each cable geometry. Considerations will include the size of the cable and the expected thermal uniformity, as well as local measurements required to guide the planned cooling process. The temperature can be adjusted for different solders or different types of HTS materials. This optimized time-temperature curve for solder filling (or more generally, metal filling) of HTS cables is unique to the process described herein and is one factor contributing to the success of the described technology, even when using solders (such as Sn 60 Pb 40 ) with melting temperatures high enough to potentially (or possibly) damage the HTS.

[0072] Alternative solder alloys that reduce degradation can also be used. The selection of a suitable solder for a given application will depend on the performance required for the cable application - including but not limited to mechanical, thermal, and electrical properties.

[0073] Actions 409 and 410 can be performed as a loop to ensure that in Action 409, the molten metal flows through the entire cable assembly. In some embodiments, the flow of the molten metal through the entire cable assembly can be achieved at least in part via gravity (i.e., at atmospheric pressure), via a displacement pump, or using vacuum pressure techniques.

[0074] In Action 410, once it is determined that sufficient molten metal has flowed through the portion (or portions) of the cable assembly where the HTS material is disposed, the flow of the molten metal is stopped in Action 411, and one or more cooling devices are used to cool the molten metal and the HTS cable assembly (Action 412), and after the cooling is completed, a solder-filled (or more generally, metal-filled) HTS cable is obtained. It should be noted that in some embodiments, the flow of the molten metal (e.g., liquid solder) does not stop as long as the metal passes through the cable. Instead, the metal flow is stopped until a predetermined amount of metal has passed through the cable and a dump has been reached. Once the metal returns to the solid state, flowing additional metal beyond simply filling the cable may be beneficial for removing flux from the cable and / or reducing the porosity in the metal-filled cable.

[0075] In Figure 4A and Figure 4B the exemplary method shown, it should be understood that an HTS cable can be formed without the need to perform all of the processing actions shown in Figure 4A 、 Figure 4B and / or in the specific order presented. As a non-limiting example, depending on the cleanliness of the received preform, the cleaning in Action 401 may not be necessary in all cases. Additionally, in at least some cases, some parts of the method can be performed simultaneously. As a non-limiting instance, in some cases, the flux application in Action 404 can be performed after evacuating the HTS cable assembly in Action 405. As another non-limiting instance, in some cases, heating the HTS cable assembly in Action 406 and melting the metal in Action 407 can be performed simultaneously, or either step can start or even be completed before the other step begins. In some cases, the actions (and / or some parts of the actions) of the illustrative method shown in Figure 4A and Figure 4B can be completely omitted. For example, in some embodiments, the action of applying and discharging flux to the HTS material in Action 404 can be omitted. In some embodiments, the purging aspect of Action 405 can be omitted when performing the evacuation aspect of Action 404.

[0076] In addition to Figures 4A to 4B the processes shown and described above, any techniques shown or described in the PCT application No. PCT / US2020 / 060170, filed on November 12, 2020, entitled "Processes, Systems and Devices for Metal Filling of High Temperature Superconductor Cables", which is incorporated herein by reference in its entirety, may also be used to produce superconducting cables as described herein.

[0077] Figure 5 depicts a cooling system that can be operated to cool an HTS cable assembly (e.g., in Figures 4A to 4B behavior 412 of the method shown). In Figure 5 an example, the cooling system 500 includes one or more cooling devices (e.g., blowers or fans or other air moving devices) and one or more movable heating units (e.g., heaters). In Figure 5 an illustrative embodiment, the cooling system 500 includes two movable blowers (or fans) as cooling devices and a pair of heaters. The cooling system is thermally coupled to the HTS cable assembly 506. One or more end heaters 504 may be thermally coupled to opposite ends of the HTS cable, while the two blowers are thermally coupled to the HTS cable assembly 506 but are movable relative to the HTS cable. In an embodiment, the end heaters may be used with the cooling system or used without the cooling system to keep the liquid solder near the ends for as long as possible.

[0078] During operation of the cooling system 500, cooling begins when the first and second cooling elements are directed towards a first region 508a or section of the HTS cable (identified by the reference numeral "1" in Figure 5 and hereinafter referred to as "section 1" or "region 1"). A thermocouple (represented as TC11 in Figure 5 ) is disposed in or near section 1 of the cable. Thermocouples (represented as TC10 or TC12 in Figure 5 ) are disposed in or near section 2 of the cable. Once the thermocouples TC10, TC11, and TC12 indicate that the liquid metal in and adjacent to that section (i.e., section 1 and section 2 have solidified), the cooling elements are moved to or otherwise directed towards one or more sections of the cable assembly adjacent to section 1. In this example, the cooling elements are moved to two sections adjacent to section 1, each section designated as section 2. (In Figure 5is identified by the reference numeral "2" in the drawings and hereinafter referred to as "section 2" or region 2). Once the thermocouples TC9 and TC13 indicate that the molten metal in the next section (i.e., section 3) is solid, the cooling element is moved to section 3 and then to section 4 and so on, and the process is repeated for each section. In some embodiments, it may be preferred to position the thermocouple substantially in the middle of the section. However, the thermocouple can also be placed in other parts of the section.

[0079] In operation, the cooling element is initially aligned with the central portion of the cable (and desirably with the center of the cable), and the temperature along the cable is monitored (e.g., via a thermocouple or any other suitable device for monitoring temperature). As each region of the cable solidifies (e.g., it becomes apparent from a period of constant temperature followed by a temperature decrease), the cooling element is moved to that section (or region) to more rapidly cool that section and create a gradient towards the next (section). Thus, as Figure 5 shown, both cooling elements 501a, 501b are initially directed towards region 1 (i.e., TC11), and then moved to region 2 (e.g., one cooling element is moved to section 2 508b, and the other cooling element is moved to section 2 508c), then to section 3 508d, 508d, and so on until each cable region has been cooled. The number of regions used for this process can be adapted according to the length of the cable. Using this scheme, the risk of "trapping" liquid can be avoided by waiting until the region is solid before cooling adjacent regions.

[0080] Combined Figure 5 The cooling system and process described are applicable to cables having a length greater than about 2 m. The method has been successfully applied to cables up to about 3 m in length, and suitable mechanical and electrical properties have been demonstrated in tests at high magnetic fields. The upper limit on the cable length for this method can be set by cooling due to natural convection and can be increased by increasing the ambient temperature around the HTS cable assembly 506.

[0081] Figure 6 is a three-dimensional graphic of a fusion machine according to some embodiments, having a cutaway portion to show various components of a tokamak device. The magnets within the fusion machine can be formed from superconducting cables as described above. Figure 6 shows a partial cross-section through the fusion machine 600 and includes magnet coils (electromagnetic coils) 613, a neutron shield 612, and a core region 611 made of or otherwise incorporating superconducting cables as described above. According to some embodiments, the magnet coils 613 can be a central solenoid and / or other poloidal field solenoid coils, or can form part thereof.

[0082] Those of ordinary skill in the art will appreciate other embodiments of the concepts, structures, processes, results, and techniques disclosed herein. It should be understood that superconducting cables configured according to the concepts, structures, processes, and techniques described herein can be used in a variety of applications, including applications where the superconducting cable is wound into a coil to form a magnet. For example, one such application is nuclear magnetic resonance (NMR) studies of, for example, solid state physics, physiology, or proteins, for which such a cable can be wound into a magnet. Another application is clinical magnetic resonance imaging (MRI) for performing medical scans of a living organism or a part thereof, for which a compact high-field magnet is required. Yet another application is high-field MRI, which requires a large-bore solenoid. Still another application is magnetic research in physics, chemistry, and materials science. Further applications are magnets for particle accelerators for materials processing or inspection; electrical power generators; medical accelerators commonly used for proton therapy, radiotherapy, and radiation generation; superconducting energy storage; magnetohydrodynamic (MHD) generators; and materials separation, such as in mining, semiconductor manufacturing, and recycling. It should be understood that the above list of applications is not exhaustive, and that there are other applications in which the concepts, structures, processes, and techniques disclosed herein can be implemented without departing from their scope.

[0083] Accordingly, having described several aspects of at least one embodiment of the disclosed concepts, structures, processes, and techniques, it should be understood that various changes, modifications, and improvements will readily occur to those skilled in the art.

[0084] Such changes, modifications, and improvements should be part of this disclosure and should fall within the spirit and scope of the concepts, structures, processes, and techniques described herein. Additionally, although the advantages of the present invention have been pointed out, it should be understood that not every embodiment of the techniques described herein will include every described advantage. Some embodiments may not embody any of the features described as advantageous herein, and in some cases, one or more of the described features may be embodied to obtain further embodiments. Accordingly, the foregoing description and drawings are merely illustrative.

[0085] The various aspects of the concepts, structures, processes, and techniques described herein can be used alone, in combination, or in various arrangements not specifically described in the foregoing embodiments, and thus their application is not limited to the details and arrangements of the components set forth in the foregoing description or shown in the drawings. For example, the aspects described in one embodiment can be combined with the aspects described in other embodiments in any manner. Other illustrative aspects include:

[0086] Aspect 1. A cable, comprising: a conductive structure extending along the cable and including a channel, the channel including a main channel portion and a side channel portion, the side channel portion being in fluid communication with or otherwise coupled or connected to the main channel portion and disposed beside the main channel portion; a high temperature superconductor (HTS) tape stack disposed within the main channel portion of the channel; and solder disposed within the side channel portion of the channel and at least a portion of the main channel portion of the channel.

[0087] Aspect 2. The cable according to Aspect 1, wherein the solder in at least a portion of the main channel portion of the channel and the solder in the side channel portion of the channel form a continuous solder region.

[0088] Aspect 3. The cable according to Aspect 1, wherein an opening between the main channel portion and the side channel portion of the channel is smaller than the HTS tape stack.

[0089] Aspect 4. The cable according to Aspect 1, further comprising a metal sheath surrounding the conductive structure, and wherein the side channel portion of the channel extends at least partially into the metal sheath.

[0090] Aspect 5. The cable according to Aspect 1, wherein the conductive structure includes a plurality of channels, each channel including a corresponding HTS tape stack.

[0091] Aspect 6. The cable according to Aspect 1, wherein the conductive structure is one of a plurality of conductive segments extending along the cable and each including a corresponding channel in which an HTS tape stack is disposed.

[0092] Aspect 7. The cable according to Aspect 6, wherein none of the plurality of conductive segments directly contacts any other conductive segment.

[0093] Aspect 8. The cable according to Aspect 6, wherein the plurality of conductive segments exhibit radial symmetry about a central axis of the cable.

[0094] Aspect 9. The cable according to Aspect 8, wherein the plurality of conductive segments are twisted about the central axis of the cable, and wherein the HTS tape stacks follow a helical path about the central axis.

[0095] Aspect 10. The cable according to Aspect 6, further comprising electrical insulating material disposed between adjacent conductive segments of the plurality of conductive segments, the electrical insulating material electrically insulating the plurality of conductive segments from each other.

[0096] Aspect 11. The cable according to Aspect 1, wherein the cable further comprises at least one internal cooling channel.

[0097] Aspect 12. The cable according to aspect 6, wherein the plurality of conductive segments comprises copper.

[0098] Aspect 13. The cable according to aspect 1, wherein the HTS tape stack comprises a rare earth barium copper oxide superconductor.

[0099] Aspect 14. A method comprising: at least partially filling a channel of a high temperature superconductor (HTS) cable assembly with molten metal, the HTS cable assembly comprising: a conductive structure extending along the HTS cable assembly and including the channel, the channel including a main channel portion and a side channel portion connected to and disposed beside the main channel portion; and a high temperature superconductor (HTS) tape stack disposed within the main channel portion of the channel, wherein at least partially filling the channel comprises directing the molten metal into the side channel portion of the channel and into the main channel portion of the channel; and operating one or more cooling devices to cool the molten metal in the channel.

[0100] Aspect 15. The method according to aspect 14, wherein the HTS cable assembly includes a former in which the channel is disposed.

[0101] Aspect 16. The method according to aspect 15, wherein the former includes four channels, each channel including HTS, and wherein the method includes at least partially filling the four channels of the former.

[0102] Aspect 17. The method according to aspect 16, wherein the HTS cable assembly further includes a sheath disposed around the former.

[0103] Aspect 18. The method according to aspect 14, including completely filling at least one channel of the HTS cable assembly.

[0104] Aspect 19. The method according to aspect 15, wherein at least partially filling the channel of the HTS cable assembly with molten metal includes: heating the HTS cable assembly; and applying pressure to the molten metal to force the molten metal through the channels of the former.

[0105] Aspect 20. The method according to aspect 19, wherein the molten metal is held in a container, and wherein applying pressure to the molten metal includes applying pressure to the molten metal within the container.

[0106] Aspect 21. The method according to aspect 14, wherein the molten metal comprises a PbSn solder.

[0107] Aspect 22. A cable, comprising: a conductive structure extending along the cable and including a channel, the channel including a main channel portion and a secondary portion; a high temperature superconductor (HTS) tape stack disposed within the main channel portion of the channel; and solder disposed within the secondary portion of the channel and at least a portion of the main channel portion of the channel.

[0108] Aspect 23. The cable according to aspect 22, wherein the solder in at least a portion of the main channel portion of the channel and the solder in the secondary portion of the channel form a continuous solder region.

[0109] Aspect 24. The cable according to aspect 23, wherein an opening between the main channel portion and the secondary portion of the channel is smaller than the HTS tape stack.

[0110] Aspect 25. A cable, comprising: a conductive structure extending along the cable and including a channel, the channel including a main channel portion; a sheath structure at least partially surrounding the conductive structure, the sheath structure including a side channel portion connected to and disposed beside the main channel portion of the conductive structure; a high temperature superconductor (HTS) tape stack disposed within the main channel portion of the channel; and solder disposed within the side channel portion of the sheath structure and at least a portion of the main channel portion of the channel.

[0111] Aspect 26. The cable according to aspect 25, wherein the solder in at least a portion of the main channel portion of the channel and the solder in the side channel portion of the channel form a continuous solder region.

[0112] Aspect 27. The cable according to aspect 26, wherein an opening between the main channel portion and the side channel portion of the channel is smaller than the HTS tape stack.

[0113] In addition, the described concepts, structures, processes, and techniques can be embodied as methods for which examples have been provided. The acts performed as part of a method can be ordered in any suitable way. Accordingly, embodiments can be constructed in which the acts are performed in a different order than shown, which can include performing some acts simultaneously, even though they are shown as sequential acts in the illustrative embodiments.

[0114] The use of ordinal terms such as "first", "second", "third", etc. in the claims to modify the claim elements themselves does not mean any priority, precedence, or order of one claim element with respect to another claim element, or the chronological order of acts of performing a method, but is only used as a label to distinguish one claim element having a particular name from another element having the same name (except for using the ordinal term) to distinguish the claim elements.

[0115] The terms "about" and "approximately" can be used to mean within ±20% of the target value in some embodiments, within ±10% of the target value in some embodiments, within ±5% of the target value in some embodiments, and within ±2% of the target value in some embodiments. The terms "about" and "approximately" can encompass the target value. The term "substantially equal" can be used to indicate within ±20% of each other in some embodiments, within ±10% of each other in some embodiments, within ±5% of each other in some embodiments, and within ±2% of each other in some embodiments.

[0116] The term "substantially" can be used to indicate a value within ±20% of a comparative measurement (value) in some embodiments, within ±10% in some embodiments, within ±5% in some embodiments, and within ±2% in some embodiments. For example, a first direction that is "substantially" perpendicular to a second direction can indicate a first direction that is within ±20% of a 90° angle with the second direction in some embodiments, within ±10% of a 90° angle with the second direction in some embodiments, within ±5% of a 90° angle with the second direction in some embodiments, and within ±2% of a 90° angle with the second direction in some embodiments.

[0117] Furthermore, the language and terminology used herein are for descriptive purposes and should not be regarded as limiting. The use of "comprising", "including", or "having", "containing", "involving", and variations thereof herein is intended to cover the items listed thereafter and their equivalents as well as additional items.

Claims

1. A cable, which comprises: a conductive structure extending along the cable and including a channel, the channel including a main channel portion and a side channel portion connected to the main channel portion and disposed beside the main channel portion; a high-temperature superconductor (HTS) tape stack disposed within the main channel portion of the channel; and solder disposed within the side channel portion of the channel and at least a portion of the main channel portion of the channel.

2. The cable according to claim 1, wherein the solder in at least a portion of the main channel portion of the channel and the solder in the side channel portion of the channel form a continuous solder region.

3. The cable according to claim 1, wherein an opening between the main channel portion and the side channel portion of the channel is smaller than the HTS tape stack.

4. The cable according to claim 1, further comprising a metal sheath surrounding the conductive structure, and wherein the side channel portion of the channel extends at least partially into the metal sheath.

5. The cable according to claim 1, wherein the conductive structure includes a plurality of channels, each channel including a corresponding HTS tape stack.

6. The cable according to claim 1, wherein the conductive structure is one of a plurality of conductive segments extending along the cable and each including a corresponding channel in which an HTS tape stack is disposed.

7. The cable according to claim 6, wherein none of the plurality of conductive segments directly contacts any other conductive segment.

8. The cable according to claim 6, wherein the plurality of conductive segments exhibit radial symmetry about a central axis of the cable.

9. The cable according to claim 8, wherein the plurality of conductive segments are twisted about the central axis of the cable, and wherein the HTS tape stack follows a helical path about the central axis.

10. The cable according to claim 6, further comprising electrical insulating material disposed between adjacent conductive segments of the plurality of conductive segments, the electrical insulating material electrically insulating the plurality of conductive segments from each other.

11. The cable according to claim 1, wherein the cable further includes at least one internal cooling channel.

12. The cable according to claim 6, wherein the plurality of conductive segments include copper.

13. The cable according to claim 1, wherein the HTS tape stack includes a rare earth barium copper oxide superconductor.

14. A method, which comprises: at least partially filling a channel of a high-temperature superconductor (HTS) cable assembly with molten metal, the HTS cable assembly including: a conductive structure extending along the HTS cable assembly and including the channel, the channel including a main channel portion and a side channel portion connected to the main channel portion and disposed beside the main channel portion; and an HTS tape stack disposed within the main channel portion of the channel, wherein at least partially filling the channel of the HTS cable assembly includes guiding the molten metal into the side channel portion of the channel and into the main channel portion of the channel; and operating one or more cooling devices to cool the molten metal in the channel.

15. The method according to claim 14, wherein, the HTS cable assembly includes a former in which the channels are arranged.

16. The method according to claim 15, wherein, the former includes four channels, each channel includes HTS, and wherein the method includes at least partially filling the four channels of the former.

17. The method according to claim 16, wherein, the HTS cable assembly further includes a sheath arranged around the former.

18. The method according to claim 14, including completely filling at least one channel of the HTS cable assembly.

19. The method according to claim 15, wherein, at least partially filling the channels of the HTS cable assembly with molten metal includes: heating the HTS cable assembly; and applying pressure to the molten metal to force the molten metal through the channels of the former.

20. The method according to claim 19, wherein, the molten metal is held in a container, and wherein applying pressure to the molten metal includes applying pressure to the molten metal within the container.

21. The method according to claim 14, wherein, the molten metal includes PbSn solder.

22. A cable, which comprises: a conductive structure extending along the cable and including channels, the channels including a main channel portion and a secondary portion; a high temperature superconductor (HTS) tape stack arranged within the main channel portion of the channel; and solder arranged within the secondary portion of the channel and at least a portion of the main channel portion of the channel.

23. The cable according to claim 22, wherein, the solder in at least a portion of the main channel portion of the channel and the solder in the secondary portion of the channel form a continuous solder region.

24. The cable according to claim 23, wherein, the opening between the main channel portion and the secondary portion of the channel is smaller than the HTS tape stack.

25. A cable, which comprises: a conductive structure extending along the cable and including channels, the channels including a main channel portion; a sheath structure arranged at least partially around the conductive structure, the sheath structure including a side channel portion connected to and arranged beside the main channel portion of the conductive structure; a high temperature superconductor (HTS) tape stack arranged within the main channel portion of the channel; and solder arranged within the side channel portion of the sheath structure and at least a portion of the main channel portion of the channel.

26. The cable according to claim 25, wherein, the solder in at least a portion of the main channel portion of the channel and the solder in the side channel portion of the channel form a continuous solder region.

27. The cable according to claim 26, wherein, the opening between the main channel portion and the side channel portion of the channel is smaller than the HTS tape stack.

28. A high temperature superconductor (HTS) cable assembly, which comprises: At least one conductive structure extending along the cable and including a main channel portion and a side channel portion, with an opening between the main channel portion and the side channel portion such that the main channel portion and the side channel portion are in fluid communication; and An HTS tape stack disposed within the main channel portion, with at least a portion of the HTS tape stack being close to the opening between the main channel portion and the side channel portion.

29. The HTS cable assembly according to claim 28, wherein, The size of the opening between the main channel portion and the side channel portion is selected such that the HTS tape stack does not move into the side channel portion.

30. The HTS cable assembly according to claim 28, further comprising a metal sheath disposed around the at least one conductive structure.

31. The HTS cable assembly according to claim 28, wherein, The at least one conductive structure is provided as a plurality of conductive structures, each of the plurality of conductive structures corresponding to a conductive section, and each of the plurality of conductive sections having a shape defining a main channel portion and a side channel portion. A plurality of HTS tape stacks, each of the plurality of HTS tape stacks being disposed in a respective one of the main channel portions.

32. The HTS cable assembly according to claim 31, further comprising an insulator disposed between adjacent conductive sections of the plurality of conductive sections, the size and shape of the insulator being selected such that the plurality of conductive sections are electrically insulated from each other.

33. The HTS cable assembly according to claim 31, wherein: The plurality of conductive sections are disposed around the central longitudinal axis of the HTS cable assembly; and The HTS tape stacks follow a helical path around the central longitudinal axis of the HTS cable assembly.

34. The HTS cable assembly according to claim 31, further comprising an electrically insulating material disposed between adjacent conductive sections of the plurality of conductive sections, the electrically insulating material electrically insulating the plurality of conductive sections from each other.

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