Superconducting cable with solder channel

Abstract

Techniques are described that allow HTS cables to be solder-filled more easily and quickly while reducing degradation to the cable's HTS performance. In particular, channels in an HTS cable can include a primary channel in which the HTS is disposed, along with a secondary channel that provides an increased hydraulic cross-section through which the solder can flow. The secondary channel may be connected to the primary channel (e.g., as a side channel). If the secondary channel has an opening in the primary channel that is smaller than the HTS material placed therein, the HTS material cannot migrate into the secondary channel, thereby providing space adjacent to the HTS material and the primary channel through which the solder can flow freely.

Description

[Background technology]

[0001]

[0001] A superconductor is a material that has no electrical resistance to electric current (is "superconducting") below a certain critical temperature. For many superconductors, the critical temperature is below 30°K, and operation of these materials in the superconducting state requires significant cooling, such as with liquid helium.

[0002]

[0002] High-field magnets are often constructed from superconductors because they can carry high currents without resistance. Such magnets can carry currents greater than, for example, 5 kA. Summary of the Invention [Means for solving the problem]

[0003]

[0003] In some aspects, the structures and techniques described herein relate to a cable including a conductive structure extending along the cable and including a channel, the channel including a primary channel portion and a secondary channel portion connected to the primary channel portion and positioned laterally of the primary channel portion; a stack of high temperature superconductor (HTS) tapes positioned within the primary channel portion of the channel; and solder positioned within the secondary channel portion of the channel and within at least a portion of the primary channel portion of the channel.

[0004] In some aspects, techniques described herein relate to methods that include 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 a channel, the channel including a primary channel portion and a secondary channel portion connected to and disposed laterally of the primary channel portion; and a stack of HTS tapes disposed within the primary channel portion of the channel, wherein at least partially filling the channel of the HTS cable assembly includes directing the molten metal into the secondary channel portion of the channel and into the primary channel portion of the channel. In embodiments, the method further includes operating one or more cooling devices to cool the molten metal in one or both of the secondary channel portion or the primary channel portion.

[0005]

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

[0006]

[0006] In some aspects, the techniques described herein relate to a cable including a conductive structure extending along the cable and including a channel, the channel including a primary channel portion; an outer jacket structure at least partially disposed around the conductive structure, the outer jacket structure including a secondary channel portion connected to the primary channel portion of the conductive structure and disposed beside the primary channel portion of the conductive structure; a stack of high temperature superconductor (HTS) tapes disposed within the primary channel portion of the channel; and solder disposed within the secondary channel portion of the outer jacket structure and within at least a portion of the primary channel portion of the channel.

[0007]

[0007] In some embodiments, an HTS cable assembly comprises at least one conductive structure extending along the cable and including a primary channel portion and a secondary channel portion, the primary channel portion and the secondary channel portion having an opening between the primary channel portion and the secondary channel portion so that the primary channel portion and the secondary channel portion are in fluid communication; and a stack of high temperature superconductor (HTS) tapes disposed within the primary channel portion, at least a portion of the HTS stack being proximate to the opening between the primary channel portion and the secondary channel portion.

[0008] In an embodiment, the size of the opening between the primary and secondary channel portions is selected to prevent the stack of HTS tapes from migrating into the secondary channel.

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

[0010]

[0010] In an embodiment, the HTS cable assembly includes a plurality of conductive structures, each of the plurality of conductive structures corresponding to a conductive section, each of the plurality of conductive sections having a shape defining a primary channel portion and a secondary channel portion, and each of the primary channel portions having a stack of HTS tapes disposed therein.

[0011]

[0011] In an embodiment, the HTS cable assembly further includes an insulator disposed between adjacent conductive sections of the plurality of conductive sections, the insulator having a size and shape selected to electrically insulate the plurality of conductive sections from each other.

[0012]

[0012] In an embodiment, the multiple conductive sections in the HTS cable assembly are arranged around a central longitudinal axis of the HTS cable assembly, and the stack of HTS tapes follows a spiral path around the central longitudinal axis of the HTS cable assembly.

[0013]

[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 that electrically insulates the plurality of conductive sections from each other.

[0014] The foregoing apparatus and method embodiments may be implemented by any suitable combination of the aspects, features, and acts described above or in further detail below. These and other aspects, embodiments, and features of the present teachings may be more fully understood from the following description taken in conjunction with the accompanying drawings.

[0015] Various aspects and embodiments will be described with reference to the following figures. It should be understood that the drawings are not necessarily drawn to scale. In the drawings, each identical or nearly identical component shown in various figures is represented by a like numeral. For purposes of brevity, not every component may be labeled in every figure. [Brief explanation of the drawings]

[0016] [Figure 1]

[0016] FIG. 1 illustrates a cross-sectional view of an exemplary superconducting cable, according to some embodiments. [Figure 2A]

[0017] FIG. 2A is a diagram depicting a conductive section separated from a cable within which the conductive section may be disposed, according to some embodiments. [Figure 2B] FIG. 10 depicts a conductive segment separated from a cable within which the conductive segment may be disposed, according to some embodiments. [Figure 2C]FIG. 10 depicts a conductive segment separated from a cable within which the conductive segment may be disposed, according to some embodiments. [Figure 2D] FIG. 10 depicts a conductive segment separated from a cable within which the conductive segment may be disposed, according to some embodiments. [Figure 3]

[0018] FIG. 2 illustrates a cross-sectional view of an exemplary superconducting cable including an outer jacket, according to some embodiments. [Figure 4A]

[0019] FIG. 1 is a flow diagram of a metal-filled superconducting cable method according to some embodiments. [Figure 4B] FIG. 1 is a flow diagram of a metal-filled superconducting cable method according to some embodiments. [Figure 5]

[0020] FIG. 1 is a block diagram of a cooling system comprising one or more movable fans and one or more heaters, a first heater configured to be in thermal contact with a first end of an HTS cable and a second heater configured to be in thermal contact with a second, opposite end of the HTS cable. [Figure 6]

[0021] 1 is a perspective view of a blender with portions thereof removed (cutaway) to show various internal components of the blender, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0017]

[0022] High-field superconducting magnets often have multiple electrically insulated cable turns grouped in a multi-layer configuration. When the superconducting material is cold enough to be below its critical temperature (the temperature below which the material's electrical resistance drops to zero), driving the magnet allows electrical current to pass through the superconducting path without loss. However, some or all of the superconducting material can heat up above its critical temperature for various reasons and thus lose its superconducting properties. If uncontrolled, such heating can cause the superconductor to lose its superconducting capabilities, which is often referred to as a "quench." Furthermore, if a quench is not properly handled by the system (e.g., by shutting down), components can be damaged by the heating.

[0018]

[0023] Some superconducting magnet systems handle quench events through a system of active alarms and detection mechanisms. Other superconducting magnet systems handle quenches passively through the design of the superconducting magnet itself. An example of the latter approach is a non-insulated (NI) magnet, in which adjacent superconducting turns of the magnet are not insulated from one another but are instead separated by conventional conductors (i.e., not superconductors) (further referred to as a non-insulated (NI) magnet). When the magnet is operating below the critical temperature of the superconductor, current flows through the superconductor but not across the turns because the superconductor has zero resistance compared to the finite resistance of the conductors that exist between the turns.

[0019]

[0024] Some designs of superconducting cables can include high-temperature superconductor (HTS) material disposed within a conductive structure. For example, a cable can include a conductive structure that supports one or more HTS tapes. The conductive structure, sometimes referred to as a "former," can include multiple channels within which the HTS tapes are disposed. However, this configuration can result in a small gap between the HTS and the former, which can reduce the cable's ability to carry current and increase the cable's susceptibility to quenching. The cable can be insulated or can be mounted within a conductive support structure to create a non-insulated magnet.

[0020]

[0025] In a so-called Vacuum Pressure Impregnation (VPI) process, one or more HTS magnet structures (e.g., HTS material disposed within a conductive structure) are heated to force molten solder through and into open channels within the structure. The solder can flow into the open spaces within the magnet structure, filling them with conductive material. In some cases, this process may be performed at a relatively low temperature (e.g., around 200°C) to allow the solder to flow through the structure.

[0021]

[0026] Exposure to molten solder can corrode or otherwise damage the HTS tape. For example, exposure to molten solder can corrode the protective copper cladding around the HTS tape. Therefore, in some cases, it may be desirable to reduce the duration that molten solder is in contact with the HTS tape during the VPI process. Furthermore, HTS cables that are twisted prior to the VPI process can be difficult to fill efficiently due to the open space around the twisted HTS material within the cable, which can be relatively small compared to the diameter of the cable. In some cases, the relatively small space can become blocked and hinder solder flow.

[0022]

[0027] The techniques described herein allow HTS cables to be solder filled more easily and quickly with less degradation to the performance of the HTS in the cable than previous techniques.

[0023]

[0028] In particular, the channels in an HTS cable can include a primary channel in which the HTS is disposed, along with a secondary channel that provides an increased hydraulic cross-section through which the solder can flow. The secondary channel may be connected to the primary channel (e.g., as a side channel). If the secondary channel is connected to the primary channel through an opening that is smaller than the HTS material located in the primary channel, the HTS material cannot migrate into the secondary channel, thereby providing space adjacent to the HTS material and primary channel through which the solder can flow freely.

[0024]

[0029] As a result, the molten solder can flow to the desired space within the cable more efficiently, and therefore in less time, than with previous structures and techniques. As a result of this improved efficiency (e.g., improved flow rate), HTS cables can be manufactured with a lower level of degradation than achieved using conventional techniques in which the HTS cable structure does not include both primary and secondary channels. Furthermore, as a result of the improved efficiency achieved using the structures and techniques described herein, much longer HTS cables can be manufactured with a constant level of degradation (compared to conventional approaches) because the increased flow rate can produce the same amount of degradation of the HTS material during the solder flow process, even over longer flow distances.

[0025]

[0030] Figure 1 shows a cross-sectional view of an exemplary superconducting cable according to some embodiments. While the techniques described herein can be applied to any suitable superconducting cable, Figure 1 depicts an example cable in which three channels containing HTS are formed within three separate conductive sections 112 that are separated from one another by electrically insulating material 116. The following description may apply, for example, to cables in which any number of channels are disposed within a single conductive structure (e.g., having a circular cross-section).

[0026]

[0031] In the example of Figure 1, the conductive sections 112 are configured to hold respective HTS tape stacks 111 within respective channels within each section. It may be noted that cable 110 may be created from multiple instances, here three instances, of the same conductive sections 112 arranged as shown in Figure 1. The example cable of Figure 1 includes an outer jacket 119 disposed on the exterior of the conductive sections. According to some embodiments, the outer jacket 119 may comprise or consist of steel, Inconel®, Nitronic® 40, Nitronic® 50, Incoloy®, or combinations thereof.

[0027]

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

[0028]

[0033] 1, the channels formed within each of the conductive sections 112 in which the HTS tape stack 111 and solder 115 are disposed include a larger primary channel portion (i.e., the HTS tape stack 111 is disposed within each of the primary channel portions) that holds the HTS tape stack (further referred to herein as a "primary portion") and a smaller secondary portion 117 on the side of the primary portion (further referred to herein as a "minor channel portion" or "secondary portion" or "secondary channel"). In the example of FIG. 1, the primary channel portion and the minor channel portion are in fluid communication (e.g., coupled or connected).

[0029]

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

[0030]

[0035] It should be noted that in the absence of a secondary portion of a channel, the space through which the solder must pass may be limited. Accordingly, including a secondary portion may increase the hydraulic cross-section for solder flow. Accordingly, including a secondary portion of a channel (e.g., secondary portion 117) may reduce the time required for solder fill compared to the time required for solder fill when the channel does not include a secondary portion. This may be due, at least in part, to a lower 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. Upon filling the primary and secondary portions of the channel, the channel may include a continuous region of solder disposed within (and preferably filling) both the primary and secondary portions of the channel.

[0031]

[0036] Thus, omission of the secondary section may result in increased solder fill times compared to the solder fill times of a superconducting cable including channels with secondary sections. Longer solder fill times may lead to degradation (or increased degradation) of the HTS material as a result of thermal exposure during filling. Thus, including the secondary section may result in less (and ideally, minimal or no) degradation of the HTS material as a result of thermal exposure during filling.

[0032]

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

[0033]

[0038] During operation of cable 110, at least HTS tape stack 111 is cooled below its superconducting transition, allowing current to flow with zero resistance. Conductive section 112 acts as a stabilizer during a quench; if a portion of the HTS material quenches, heat can be conducted through the conductive section supporting the quenched superconductor component to other conductive sections, thereby quenching the entire cross section of the cable. Non-superconducting zones can then be created within HTS tape stack 111 and propagate along the cable.

[0034]

[0039] According to some embodiments, the conductive section 112 may include or consist of copper. Copper may represent a desirable material due to its high thermal conductivity, which may provide not only electrical conductivity but also functional stabilization in the event of a quench. Other suitable materials that the conductive section 112 may comprise or consist of include aluminum.

[0035]

[0040] According to some embodiments, the electrically insulating material 116 is positioned to contact different ones of the conductive segments 112 on either side. As shown in FIG. 1 , the electrically insulating material 116 may be positioned between adjacent pairs of conductive segments 112, contacting both segments of the pair (ideally leaving no or substantially no gaps between the electrically insulating material 116 and each conductive segment). In some embodiments, the electrically insulating material 116 may be provided in the form of a tape that may be positioned between pairs of conductive segments 112. In some cases, the tape may be an adhesive tape and may be adhered to adjacent conductive segments 112 via an adhesive so that the tape adheres to the conductive segments.

[0036]

[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 greater than 30° K, the temperature below which the electrical resistance of the material becomes zero. The critical temperature may in some cases depend on other factors, such as the presence of an electromagnetic field. When the critical temperature of a material is referred to herein, it will be understood to refer to whatever temperature happens to be the critical temperature for that material under certain conditions.

[0037]

[0042] The HTS tape stack 111 can comprise one or more lengths of HTS tape, which is a long, thin, stranded strand of HTS material with a cross-sectional dimension of thickness (or height) ranging from about 0.001 mm to about 0.1 mm, and a width ranging from about 1 mm to about 12 mm (and extending along the length of the cable, i.e., into and out of the page in the example of FIG. 1 ). In some embodiments, the HTS tape can include polycrystalline HTS and / or have a high level of grain ordering. The HTS tape stack 111 can include multiple HTS tapes arranged on top of each other along their width and length. This allows the HTS tape stack to have a thickness equal to (or approximately equal to) the thickness of an individual tape multiplied by the number of tapes in the stack.

[0038]

[0043] According to some embodiments, the electrically insulating material 116 may include polyimide (e.g., Kapton®), epoxy resin, phenolic resin, plastic, elastomer, steel (e.g., stainless steel), or a combination thereof. According to some embodiments, the insulating material may have a breakdown voltage or dielectric strength greater than 25 kV / mm, greater than 50 kV / mm, greater than 75 kV / mm, or greater than 1000 kV / mm.

[0039]

[0044] However, according to some embodiments, the electrically insulating material 116 can include or consist of a high resistivity material that is electrically conductive to some extent. In this regard, reference to the material 116 being "insulating" refers to the material 116 being much less conductive than the material comprising the conductive sections 112. For example, in some embodiments, the conductive sections 112 can include a highly conductive material such as copper, while the electrically insulating material 116 can include steel, which, while not strictly an insulator, is much more insulating than copper.

[0040]

[0045] 1, conductive section 112 can provide mechanical integrity to the cable in addition to the aforementioned benefits regarding quenching behavior. Conductive section 112 can be formed or conformed to a desired shape, providing a significant amount of structural strength to the cable. This is in contrast to other superconducting cables, such as cable-in-conduit conductor (CICC) braided cables, which feature twisted copper rods that can deform under high electromagnetic loads.

[0041]

[0046] According to some embodiments, the conductive sections 112 may be twisted along the length of the cable 110. That is, the conductive sections 112 may be twisted around the central longitudinal axis of the cable; as such, the cross-sectional view of FIG. 1 may be accurate at various points along the cable, but for the rotational orientation of the view shown, the cross-sectional view of FIG. 1 will rotate around the center of the cable as the cross-sectional view is moved along the length of the cable. A helical path is one example of a twisted path the conductive sections may follow around the central longitudinal axis of the cable. In such a configuration, the conductive sections 112 may be aligned along respective helical paths, with the center of each helix at the central longitudinal axis of the cable. Similarly, the HTS tape stack 111 may be supported by the conductive sections 112 along the length of the cable in the manner shown in FIG. 1, thereby further aligned along respective helical paths, with the center of each helix at the central longitudinal axis of the cable. By placing the HTS tape stack 111 along a twisted path, the length that the two conductive paths are parallel to each other is reduced, thereby reducing this source of inductive heating.

[0042]

[0047] 1 , cable 110 includes a central cooling channel 118, which may be a tubular cooling channel running along the longitudinal axis of the cable. In general, any number of channels may be formed or otherwise provided through the cable to provide cooling to conductive sections 112 and / or to HTS tape stack 111. Such cooling channels may, for example, provide a path for a cryogenic liquid, such as liquid helium or liquid nitrogen, to flow and transport heat away from conductive sections 112 and / or HTS tape stack 111. The coolant may be provided through the cooling channels at a high pressure, such as greater than 200 kPa (2 bar).

[0043]

[0048] 2A-2D each depict a conductive segment separated from the cable in which it may be disposed, according to some embodiments. For example, conductive segment 212 shown in FIG. 2A corresponds to conductive segment 112 shown in FIG. 1, comprising a channel including a primary region (or primary channel portion) 215 and a secondary region (or secondary channel portion) 216. Secondary region 216 is concave and semicircular in cross section.

[0044]

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

[0045]

[0050] In the example shown in Figure 2B, conductive section 222 comprises a channel including a primary region (or primary channel portion) 225 and secondary regions (or minor channel portions) 226 and 227, which are wedge-shaped (or "flared") regions located on either side of the primary region. In the example of Figure 2C, conductive section 232 comprises a channel including a primary region (or primary channel portion) 235 and secondary region (or minor channel portion) 236, which is a wedge-shaped (or "flared") region located next to the primary region around the periphery of the section.

[0046]

[0051] 2D, conductive section 242 comprises a first channel (or primary channel portion) 245 and a secondary channel (or sub-channel portion) 246 that is not formed as a continuous channel but instead is formed as a separate channel within the section. This approach may have the advantage of reducing the potential impact on the strength of the section due to larger channels, however, it may also have the disadvantage that the solder fills farther from the HTS material and cannot easily fill this space.

[0047]

[0052] As an alternative to the above approach, when the former is disposed within the outer skin structure, secondary regions of the channels (also known as sub-channel portions) may be formed on top of the primary channel portions. This approach is illustrated in FIG. 3, which shows a cross-sectional view of a superconducting cable 300. In the example of FIG. 3, the cable comprises a single conductive structure 312 in which three primary channel portions are formed. The secondary channel portions are formed within the outer skin structure 321. For example, one channel primary portion 316 is formed within the conductive structure 312, with secondary portion 317 formed within the outer skin structure 321.

[0048]

[0053] In the example of FIG. 3, the skin structure 321 may be, for example, a stainless steel skin wrapped within a dielectric layer 323 (eg, a layer of polyimide such as Kapton®, fiberglass cloth, etc.).

[0049]

[0054] In some embodiments, the cable assembly can be wrapped in a dielectric (e.g., fiberglass cloth, polyimide), and then a vacuum can be applied to fill the remaining space between the cable turns with a dielectric such as an epoxy resin. For example, the cable assembly can be wrapped in a first dielectric, arranged in several turns, and then a vacuum can be applied to fill with epoxy. The epoxy can be cured by heat or another means.

[0050]

[0055] In some embodiments, the cable assembly may be disposed within a structural matrix. For example, the outer jacket may include several channels within which the windings of the cable assembly (or the windings of multiple cable assemblies) may be disposed. The outer jacket may thus function as a structural support (e.g., a structural plate) for supporting the multiple windings of one or more cable assemblies. Such an outer jacket may, in some embodiments, be surrounded by one or more dielectric layers, as described above.

[0051]

[0056] 4A-4B are flow diagrams of metal-filled superconducting cable methods, according to some embodiments. Unless expressly stated, it should be understood that the process acts in the flow diagrams are unordered and that it is intended that the process acts listed in the flow diagrams may be performed in any convenient order.

[0052]

[0057] 4A and 4B, an exemplary process for filling an HTS cable (e.g., any of the cables described herein) with metal (e.g., solder) begins with cleaning one or more components of the cable that will be subjected to the metal filling process (e.g., any of the components described above, such as one or more channels of a conductive structure, one or more channels of one or more conductive sections, channels in a former, HTS material, jacket, fittings, or combinations thereof) in act 401. In some embodiments, act 401 includes cleaning one or more cable components by washing the one or more cable components with an acidic solution and then rinsing the components with water and / or another liquid. Details of an illustrative example of such a process are described below.

[0053]

[0058] Hereinafter, the material for filling will be generally referred to as "metal" for convenience, however, the material need not be a pure metal but may be, for example, a metal alloy, and therefore, in the following description, references to "metal" as used in the process should be understood to also encompass metal alloys.

[0054]

[0059] As one non-limiting example of a step 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 to the cable former, and the water / cleaning solution mixture is pumped or otherwise transferred from the reservoir into the cable former. A rinsing fluid (e.g., clean water) is then pumped into the cable former to rinse the water / cleaning solution mixture from the cable former. In some cases, the water / cleaning solution mixture and / or the rinsing liquid may be heated to a temperature above room temperature (e.g., up to 60°C (140°F)).

[0055]

[0060] After cleaning the components in act 401, in act 402, HTS material is disposed within one or more channels of the conductive structure and / or within one or more channels of one or more conductive sections, thereby creating an HTS construction as described above (e.g., the construction of HTS tape stack 111 within conductive section 112, as shown in FIG. 1). In some embodiments, the HTS material disposed within one or more channels in act 402 can include one or more stacks of HTS tapes. In some embodiments, the HTS tape stack can be pre-soldered to ensure adequate bonding between the tapes (e.g., a bond that securely connects the tapes together). In some embodiments, the HTS tape stack can be pre-soldered with a metal to be used to fill the cable. In some embodiments, the HTS tapes are pre-plated with lead-tin (PbSn) solder (or a lead-tin solder alloy).

[0056]

[0061] In act 403, a so-called "free HTS cable assembly" (or more simply, "HTS cable assembly") is formed. The HTS cable assembly is sometimes referred to as a "free cable assembly" because at least the HTS material (and possibly other components) are not structurally fixed to a channel or other structure that forms part of the HTS cable. The HTS cable assembly may be created directly as a result of placing the HTS material inside one or more channels in act 402, or may be created as a result of additional steps after act 402.

[0057]

[0062] As used herein, "HTS cable assembly" or "free HTS cable assembly" may refer to a cable structure including HTS material (e.g., HTS tape), examples of which are provided herein. For example, one type of HTS cable assembly includes HTS material, including optional additional fittings, disposed within a channel of a former. In some embodiments, the HTS cable assembly may include HTS tape disposed at the bottom of the channel. In the exemplary embodiment above, the cable former is shown as having a circular cross-sectional shape, but 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).

[0058]

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

[0059]

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

[0060]

[0065] Then, in act 405, the HTS cable assembly is evacuated (e.g., by placing the HTS cable assembly in a chamber and evacuating the chamber), and the HTS cable assembly is purged with a gas, such as an inert gas. In embodiments in which flux was applied in act 404, excess flux (e.g., flux that does not adhere to the HTS materials or components) may be expelled from the assembly as a result of the evacuation of act 405. However, it has been found that remaining flux can be effectively washed away by a flow of heavier molten metal solder (described in connection with act 409). Thus, depending on the amount of flux remaining in the assembly, a distinct step to evacuate excess flux may not be required. In embodiments having long and complex cable geometries, pressurization may be used to evacuate excess flux. Following the fluxing process, if used, the cable assembly is further evacuated and purged with an inert gas to remove oxygen, if present, which, when heated, would interfere with the effective action of the flux.

[0061]

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

[0062]

[0067] In some embodiments, act 406 may include heating the HTS cable assembly and any associated fittings and tubing in an oven, such as a convection oven. This type of heating can provide some uniformity while reducing (ideally minimizing) the need for external temperature control, and importantly, reduces (ideally avoids) the risk that the HTS tape temperature will exceed the oven set point, causing degradation of portions of the HTS tape (and therefore portions of the cable) due to exposure to undesirable temperatures.

[0063]

[0068] Before, after, or simultaneously with heating the cable assembly in act 406, the metal that will fill the HTS cable assembly is melted to a liquid state (or, in the case of an alloy, a solid / liquid state) in act 407. The metal may be melted, for example, in a container (sometimes referred to herein as a can or crucible) using a temperature-controlled heater. Thermocouples inside and / or outside the can may 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 may be melted inside an oven in which the cable is placed, while in other embodiments, the metal may be melted separately (e.g., outside the oven). The HTS cable assembly is then heated in act 408 to a temperature at which the metal should flow.

[0064]

[0069] One aspect of the metal loading process that has proven important is obtaining a desirable time-temperature profile: the temperature needs to be high enough for the metal to be a fluid with low viscosity, but the resulting exposure is low enough to avoid thermal degradation and degradation due to chemical attack of the metal on the HTS material (e.g., rare earth barium copper oxide (REBCO) tape stack).

[0065]

[0070] In some embodiments for solder filling an HTS cable having an HTS tape stack including a layer of REBCO tape with lead-tin (PbSn) solder, two steps may be performed. First, an oven is set to a temperature that warms the HTS cable assembly but does not degrade (or substantially degrade) the HTS tape. In some embodiments, the oven may be set to a temperature below the melting point of the solder to be disposed on the HTS tape (e.g., the oven may be set to heat to 185°C when the process is to fill a cable with PbSn solder), thereby significantly 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 oven setpoint. The oven setpoint is held at this temperature until the solder supply (e.g., the supply of solder in a can) is completely melted and equilibrated with the process temperature of approximately 200°C. Then, second, the oven temperature may be set to a temperature that achieves the desired flow temperature of the solder. In embodiments utilizing PbSn solder, the oven temperature may be set to a temperature of approximately 205°C, with a wait period until all points on the cable and any associated tubing required for the metal filling process have achieved the desired flow temperature (e.g., a flow temperature of approximately 200°C for PbSn solder), with temperature monitoring to ensure that no point in the HTS cable assembly exceeds a temperature of approximately 200°C. In some embodiments, the dwell time may be performed at an intermediate temperature, such as around 194°C. This approach 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, preferably immediately, to reduce, and ideally minimize, the time the HTS tape stack is exposed to such relatively high temperatures (e.g., temperatures above approximately 200°C).

[0066]

[0071] The application and monitoring of multiple temperature monitoring devices (e.g., thermocouples) at the metal-filling processing station and at multiple points on the cable can be important to 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 and expected thermal uniformity of the cable, as well as the local measurements needed to guide the planned cooling process. Temperatures can be adjusted for different solders or different types of HTS materials. Such an optimized time-temperature profile for solder filling (or, more generally, metal filling) of HTS cables is unique to the process described herein and is one factor leading to the success of the described technique, even when solders such as Sn60Pb40 are used, whose melting temperatures are high enough to potentially damage the HTS.

[0067]

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

[0068]

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

[0069]

[0074] Once a determination is made in act 410 that sufficient molten metal has flowed through the portion of the cable assembly in which the HTS material is disposed, the flow of molten metal is stopped in act 411, the molten metal and HTS cable assembly are cooled using one or more cooling devices (act 412), and after cooling is complete, a solder-filled (or, more generally, metal-filled) HTS cable is obtained. Note that in some embodiments, the flow of molten metal (e.g., liquid solder) does not stop immediately after the metal passes through the cable. Rather, the metal flow is not stopped until a predetermined amount of metal has been deposited through the cable. Flowing additional metal beyond simply filling the cable can be beneficial in removing flux from the cable and / or in reducing the void content of the metal-filled cable once the metal returns to a solid state.

[0070]

[0075] It will be understood that in the exemplary method shown in FIGS. 4A and 4B , an HTS cable may be formed without performing all of the processing acts shown in FIGS. 4A and 4B and / or in the particular order presented. As one non-limiting example, depending on the cleanliness of the received former, the cleaning process in act 401 may not be necessary in all cases. Furthermore, in at least some cases, several portions of the method may be performed simultaneously. As one non-limiting example, in some cases, the application of flux in act 404 may occur after the evacuation of the HTS cable assembly in act 405. As another non-limiting example, in some cases, the step of heating the HTS cable assembly in act 406 and the step of melting the metal in act 407 may be performed simultaneously, or either step may be initiated or even completed before the other begins. In some cases, acts (and / or portions of acts) of the exemplary method shown in FIGS. 4A and 4B may be omitted entirely. For example, in some embodiments, act 404, in which flux is applied to the HTS material and evacuated, may be omitted. In some embodiments, the vacuum aspect of act 404 may be performed, while the purifying aspect of act 405 may be omitted.

[0071]

[0076] In addition to the processes shown in Figures 4A-4B and described above, any of the techniques shown or described in PCT Application No. PCT / US2020 / 060170, filed 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 employed to produce the superconducting cables described herein.

[0072]

[0077] FIG. 5 depicts a cooling system that can be operated to cool an HTS cable assembly, such as act 412 of the method shown in FIGS. 4A-4B. In the example of FIG. 5, 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 the exemplary embodiment of FIG. 5, cooling system 500 includes two movable blowers (or fans) as cooling devices and a pair of heaters. The cooling system is thermally coupled to an HTS cable assembly 506. One or more end heaters 504 may be thermally coupled to opposing ends of the HTS cable, while two blowers are thermally coupled to the HTS cable assembly 506 but are movable relative to the HTS cable. In embodiments, the end heaters may be used with or without a cooling system to maintain as much liquid solder near the ends as possible.

[0073]

[0078] During operation of the cooling system 500, cooling begins with first and second cooling elements directed toward a first region 508a or zone of the HTS cable (identified by reference numeral "1" in FIG. 5 and hereafter referred to as "Zone 1" or "Region 1"). A thermocouple (designated TC11 in FIG. 5) is disposed within or adjacent to Zone 1 of the cable. A thermocouple (designated TC10 or TC12 in FIG. 5) is disposed within or adjacent to Zone 2 of the cable. Once thermocouples TC10, TC11, and TC12 indicate liquid metal in and adjacent to this zone (i.e., Zones 1 and 2 have solidified), cooling elements are moved or otherwise directed to one or more zones of the cable assembly adjacent to Zone 1. In this example, the cooling element is moved to two sections adjacent to Zone 1, each designated Zone 2 (identified by the reference numeral "2" in FIG. 5 and hereafter referred to as "Zone 2" or "Region 2"). When thermocouples TC9 and TC13 indicate that the molten metal in the next section (i.e., Zone 3) is solid, the cooling element is moved to Zone 3, then Zone 4, and so on, with the process repeated for each zone. In some embodiments, it may be preferred that the thermocouples be located substantially in the middle of the zones. However, thermocouples may also be located in other portions of the zones.

[0074]

[0079] In operation, the cooling elements are first aimed at the central portion of the cable (ideally the center of the cable), and the temperature along the cable is monitored (via thermocouples or any other suitable means for monitoring temperature). As each region of the cable solidifies (e.g., as evidenced by a temperature drop following a temperature period), the cooling elements are moved to that section (or region) to cool that section more rapidly and create a gradient toward the next. Thus, as shown in FIG. 5, both cooling elements 501a and 501b are first directed toward Region 1 (i.e., TC11), then moved to Region 2 (e.g., one cooling element is moved to Zone 2, 508b, and the other to Zone 2, 508c), then to Zone 3, 508d, and so on, until each cable region has been cooled. The number of regions used for this process can be adapted to the length of the cable. This approach avoids the risk of trapping liquid by waiting until one region is solid before cooling an adjacent region.

[0075]

[0080] The cooling system and process described in conjunction with Figure 5 may be suitable for cables longer than about 2 meters. This method has been successfully applied to cables up to about 3 meters in length, with suitable mechanical and electrical performance demonstrated in tests in high magnetic fields. The upper cable length limit for this method can be set by natural convection cooling and can be increased by increasing the ambient temperature in the vicinity of the HTS cable assembly 506.

[0076]

[0081] FIG. 6 is a three-dimensional view of a fusion machine with cutaway portions showing various components of a tokamak device, according to some embodiments. The magnets inside the fusion machine can be formed from the superconducting cables described above. FIG. 6 shows a partial cross section of a fusion machine 600, including magnet coils 613 fabricated from or otherwise including the superconducting cables described above, neutron shielding 612, and a core region 611. According to some embodiments, magnet coils 613 may be, or form part of, a central solenoid and / or other poloidal field solenoid coils.

[0077]

[0082] Those skilled in the art will appreciate other embodiments of the concepts, structures, processes, results, and techniques disclosed herein. It will be understood that superconducting cables constructed in accordance with the concepts, structures, processes, and techniques described herein may be useful in a wide variety of applications, including applications in which the superconducting cable is wound into a coil to form a magnet. For example, one such application is to perform nuclear magnetic resonance (NMR) studies of, for example, solid-state physics, physiology, or proteins, for which such a cable may be wound into a magnet. Another application is to perform clinical magnetic resonance imaging (MRI) for medical scanning of living organisms or portions thereof, for which a compact high-field magnet is required. Yet another application is high-field MRI, for which a large inner diameter solenoid is required. Yet another application is to perform magnetic studies of physics, chemistry, and materials science. Further applications are electrical energy generators in magnets for particle accelerators for material processing or research, medical accelerators for proton therapy, radiotherapy, and general radiation generation, superconducting energy storage, magnetohydrodynamic (MHD) electric generators, and material separation in mining, semiconductor manufacturing, recycling, etc. It is understood that the above list of applications is not exhaustive and that there are additional applications to which the concepts, structures, processes, and techniques disclosed herein can be applied without departing from their scope.

[0078]

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

[0079]

[0084] Such alternatives, modifications, and improvements are intended to be part of this disclosure and are intended to be within the spirit and scope of the concepts, structures, processes, and techniques described herein. Moreover, while advantages of the present invention are set forth, it should be understood that not all embodiments of the technology described herein will include all of the described advantages. Some embodiments may not implement the features described as advantageous herein, and in some cases, one or more of the described features may be implemented to achieve further embodiments. Accordingly, the foregoing description and drawings are merely illustrative.

[0080]

[0085] Various aspects of the concepts, structures, processes, and techniques described herein may be used alone, in combination, or in various configurations not specifically described in the previously described embodiments, and are therefore not limited in their application to the details and configurations of the components set forth in the previous description or illustrated in the drawings. For example, aspects described in one embodiment may be combined in any manner with aspects described in other embodiments. Other exemplary aspects include the following:

[0081]

[0086] Embodiment 1. A cable comprising: a conductive structure extending along the cable and including a channel, the channel including a primary channel portion and a secondary channel portion, the secondary channel portion being in fluid communication with or otherwise coupled or connected to the primary channel portion and positioned laterally of the primary channel portion; a stack of high temperature superconductor (HTS) tapes positioned within the primary channel portion of the channel; and solder positioned within the secondary channel portion of the channel and within at least a portion of the primary channel portion of the channel.

[0082]

[0087] Embodiment 2. The cable of embodiment 1, wherein the solder in at least a portion of the primary channel portion of the channel and the solder in the secondary channel portion of the channel form a continuous region of solder.

[0083]

[0088] Embodiment 3. The cable of embodiment 1, wherein the opening between the primary and secondary channel portions of the channel is smaller than the stack of HTS tapes.

[0084]

[0089] Embodiment 4. The cable of embodiment 1, further comprising a metallic sheath surrounding the conductive structure, the sub-channel portion of the channel extending at least partially into the metallic sheath.

[0085]

[0090] Embodiment 5. The cable of embodiment 1, wherein the conductive structure comprises a plurality of channels, each of the plurality of channels comprising a respective stack of HTS tapes.

[0086]

[0091] Embodiment 6. The cable of embodiment 1, wherein the conductive structure is one of a plurality of conductive sections extending along the cable, each of the plurality of conductive sections comprising a respective channel in which the stack of HTS tapes is disposed.

[0087]

[0092] Embodiment 7. The cable of embodiment 6, wherein none of the plurality of conductive segments is in direct contact with any of the other conductive segments.

[0088]

[0093] Embodiment 8. The cable of embodiment 6, wherein the plurality of conductive sections exhibit radial symmetry about a central axis of the cable.

[0089]

[0094] Embodiment 9. The cable of embodiment 8, wherein the plurality of conductive sections are twisted around a central axis of the cable, and the stack of HTS tapes follows a helical path around the central axis.

[0090]

[0095] Embodiment 10. The cable of embodiment 6, further comprising an electrically insulating material disposed between adjacent conductive segments of the plurality of conductive sections, the electrically insulating material electrically insulating the plurality of conductive segments from one another.

[0091]

[0096] Embodiment 11. The cable of embodiment 1, further comprising at least one internal cooling channel.

[0092]

[0097] Embodiment 12. The cable of embodiment 6, wherein the plurality of conductive segments comprises copper.

[0093]

[0098] Embodiment 13. The cable of embodiment 1, wherein the stack of HTS tapes comprises a rare earth barium copper oxide superconductor.

[0094]

[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 a channel, the channel including a primary channel portion and a secondary channel portion connected to and positioned beside the primary channel portion; and a stack of high temperature superconductor (HTS) tapes positioned within the primary channel portion of the channel, wherein at least partially filling the channel comprises directing molten metal into the secondary channel portion of the channel and the primary channel portion of the channel; and operating one or more cooling devices to cool the molten metal in the channel.

[0095]

[0100] Embodiment 15. The method of embodiment 14, wherein the HTS cable assembly comprises a former having the channel disposed therein.

[0096]

[0101] Embodiment 16. The method of embodiment 15, wherein the former comprises four channels, each of the four channels comprising an HTS, and the method comprises at least partially filling the four channels of the former.

[0097]

[0102] Embodiment 17. The method of embodiment 16, wherein the HTS cable assembly further includes an outer jacket disposed around the former.

[0098]

[0103] Embodiment 18. The method of embodiment 14, comprising the step of completely filling at least one channel of the HTS cable assembly.

[0099]

[0104] Embodiment 19. The method of embodiment 15, wherein the step of at least partially filling the channels of the HTS cable assembly with molten metal includes the steps of heating the HTS cable assembly and applying pressure to the molten metal to force the molten metal through the channels of the former.

[0100]

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

[0101]

[0106] Embodiment 21. The method of embodiment 14, wherein the molten metal comprises PbSn solder.

[0102]

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

[0103]

[0108] Embodiment 23. The cable of embodiment 22, wherein the solder in at least a portion of the primary channel portion of the channel and the solder in the secondary portion of the channel form a continuous region of solder.

[0104]

[0109] Embodiment 24. The cable of embodiment 23, wherein the opening between the primary channel portion and the secondary portion of the channel is smaller than the stack of HTS tapes.

[0105]

[0110] Aspect 25. A cable comprising: a conductive structure extending along the cable and including a channel, the channel including a primary channel portion; an outer jacket structure at least partially disposed around the conductive structure, the outer jacket structure including a secondary channel portion connected to the primary channel portion of the conductive structure and disposed laterally of the primary channel portion of the conductive structure; a stack of high temperature superconductor (HTS) tapes disposed within the primary channel portion of the channel; and solder disposed within the secondary channel portion of the outer jacket structure and within at least a portion of the primary channel portion of the channel.

[0106]

[0111] Embodiment 26. The cable of embodiment 25, wherein the solder in at least a portion of the primary channel portion of the channel and the solder in the secondary channel portion of the channel form a continuous region of solder.

[0107]

[0112] Embodiment 27. The cable of embodiment 26, wherein the opening between the primary and secondary channel portions of the channel is smaller than the stack of HTS tapes.

[0108]

[0113] Furthermore, the described concepts, structures, steps, and techniques may be embodied as methods, examples of which are provided. The acts performed as part of a method may be ordered in any suitable way. Thus, embodiments may be constructed in which acts are performed in an order different from that illustrated, including performing some acts simultaneously, even though shown as sequential acts in the exemplary embodiment.

[0109]

[0114] The use of ordinal terms such as "first," "second," "third," etc. in the claims to modify claim elements does not, in itself, imply any priority, ranking, or order of one claim element relative to another or the chronological order in which method actions are performed, but is merely used as a label to distinguish one claim element having a particular name from another element having the same name (apart from the use of ordinal terms) to distinguish between claim elements.

[0110]

[0115] The terms "approximately" and "about" can be used in some embodiments to mean within ±20% of a target value, in some embodiments within ±10% of a target value, in some embodiments within ±5% of a target value, and even in some embodiments within ±2% of a target value. The terms "approximately" and "about" can include the target value. The term "substantially equal" can be used to refer to values ​​that are in some embodiments within ±20% of each other, in some embodiments within ±10% of each other, in some embodiments within ±5% of each other, and even in some embodiments within ±2% of each other.

[0111]

[0116] The term "substantially" can be used to refer to values ​​that are within ±20%, in some embodiments, within ±10%, in some embodiments, within ±5%, and even in some embodiments, within ±2% of a comparative amount. For example, a first direction that is "substantially" perpendicular to a second direction can refer to a first direction that is within ±20% of an angle that forms a 90° degree with the second direction in some embodiments, within ±10% of an angle that forms a 90° degree with the second direction in some embodiments, within ±5% of an angle that forms a 90° degree with the second direction in some embodiments, and even in some embodiments, within ±2% of an angle that forms a 90° degree with the second direction.

[0112]

[0117] The phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having," "containing," "accompanying," and variations thereof herein are intended to encompass the items listed thereafter and equivalents thereof as well as additional items.

Claims

1. A cable, a conductive structure extending along the cable and including a channel, the channel including a primary channel portion and a secondary channel portion, the secondary channel portion being connected to the primary channel portion and disposed laterally of the primary channel portion; a stack of high temperature superconductor (HTS) tapes disposed within the primary channel portion of the channel; solder disposed within the secondary channel portion of the channel and within at least a portion of the primary channel portion of the channel; A cable comprising:

2. The cable of claim 1 , wherein the solder in the at least a portion of the primary channel portion of the channel and the solder in the secondary channel portion of the channel form a continuous area of ​​solder.

3. The cable of claim 1 , wherein an opening between the primary and secondary channel portions of the channel is smaller than the stack of HTS tapes.

4. The cable of claim 1 , further comprising a metallic sheath surrounding said conductive structure, said sub-channel portion of said channel extending at least partially into said metallic sheath.

5. 10. The cable of claim 1, wherein the conductive structure comprises a plurality of channels, each of the plurality of channels comprising a respective stack of HTS tapes.

6. 10. The cable of claim 1, wherein the conductive structure is one of a plurality of conductive sections extending along the cable, each of the plurality of conductive sections including a respective channel in which a stack of HTS tapes is disposed.

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

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

9. 9. The cable of claim 8, wherein the plurality of conductive sections are twisted about the central axis of the cable, the stack of HTS tapes following a helical path about the central axis.

10. 7. The cable of claim 6, further comprising an electrically insulating material disposed between adjacent conductive sections of said plurality of conductive segments that electrically insulates said plurality of conductive segments from one another.

11. The cable of claim 1 further comprising at least one internal cooling channel.

12. The cable of claim 6 , wherein the plurality of conductive sections comprises copper.

13. 10. The cable of claim 1, wherein said stack of HTS tapes comprises a rare earth barium copper oxide superconductor.

14. 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 primary channel portion and a secondary channel portion connected to and positioned laterally of the primary channel portion; a stack of HTS tapes disposed within the primary channel portion of the channel.

1. A method comprising the steps of: At least partially filling the channel of the HTS cable assembly includes directing the molten metal into the secondary channel portion of the channel and the primary channel portion of the channel; and operating one or more cooling devices to cool the molten metal in the channel.

15. The method of claim 14 , wherein the HTS cable assembly comprises a former having the channel disposed therein.

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

17. 17. The method of claim 16, wherein the HTS cable assembly further comprises an outer jacket disposed around the former.

18. 15. The method of claim 14, comprising completely filling at least one channel of the HTS cable assembly.

19. at least partially filling the channel of the HTS cable assembly with molten metal; heating the HTS cable assembly; and applying pressure to the molten metal to force it through the channels of the former.

20. 20. The method of claim 19, wherein the molten metal is held by a container, and applying pressure to the molten metal comprises applying pressure to the molten metal within the container.

21. The method of claim 14 , wherein the molten metal comprises PbSn solder.

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

23. 23. The cable of claim 22, wherein the solder in the at least a portion of the primary channel portion of the channel and the solder in the secondary portion of the channel form a continuous area of ​​solder.

24. 24. The cable of claim 23, wherein an opening between the primary channel portion and the secondary portion of the channel is smaller than the stack of HTS tapes.

25. A cable, a conductive structure extending along the cable and including a channel, the channel including a primary channel portion; an outer skin structure disposed at least partially around the conductive structure, the outer skin structure including a secondary channel portion connected to the primary channel portion of the conductive structure and disposed laterally of the primary channel portion of the conductive structure; a stack of high temperature superconductor (HTS) tapes disposed within the primary channel portion of the channel; a solder disposed within the secondary channel portion of the jacket structure and within at least a portion of the primary channel portion of the channel.

26. 26. The cable of claim 25, wherein the solder in the at least a portion of the primary channel portion of the channel and the solder in the secondary channel portion of the channel form a continuous area of ​​solder.

27. 27. The cable of claim 26, wherein an opening between the primary and secondary channel portions of the channel is smaller than the stack of HTS tapes.

28. 1. A high temperature superconductor (HTS) cable assembly comprising: at least one electrically conductive structure extending along the cable and including a primary channel portion and a secondary channel portion, the primary channel portion and the secondary channel portion having openings therebetween such that the primary channel portion and the secondary channel portion are in fluid communication; a stack of HTS tapes disposed within the primary channel portion, at least a portion of the stack of HTS tapes being proximate to the opening between the primary channel portion and the secondary channel portion; A high temperature superconductor (HTS) cable assembly comprising:

29. 30. The HTS cable assembly of claim 28, wherein the size of the opening between the primary and secondary channel portions is selected to prevent the stack of HTS tapes from migrating into the secondary channel portion.

30. 30. The HTS cable assembly of claim 28, further comprising a metallic jacket disposed about the at least one conductive structure.

31. 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, each of the plurality of conductive sections having a shape defining a primary channel portion and a secondary channel portion; 30. The HTS cable assembly of claim 28, wherein a plurality of stacks of HTS tapes are disposed within respective ones of the primary channel portions, each of the plurality of stacks of HTS tapes being a plurality of stacks of HTS tapes disposed within a respective one of the primary channel portions.

32. 32. The HTS cable assembly of claim 31, further comprising an insulator disposed between adjacent ones of said plurality of conductive segments, said insulator having a size and shape selected to electrically insulate said plurality of conductive segments from one another.

33. the plurality of conductive sections are disposed about a central longitudinal axis of the HTS cable assembly; 32. The HTS cable assembly of claim 31 , wherein the stack of HTS tapes follows a helical path around the central longitudinal axis of the HTS cable assembly.

34. 32. The HTS cable assembly of claim 31, further comprising an electrically insulating material disposed between adjacent conductive sections of said plurality of conductive sections that electrically insulates said plurality of conductive sections from one another.

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