Superconducting coil current lead arrangement

Abstract

The application provides a superconducting coil current lead device, and belongs to the technical field of superconducting magnets. The superconducting coil current lead device comprises at least one lead body arranged in the axial direction of a superconducting coil, the lead body comprising a first sector, a second sector and a connecting portion, the connecting portion being configured to communicate the first sector and the second sector, the radius of the first sector being consistent with the radius of the superconducting coil, the outer peripheral surface of the superconducting coil being wound with a binding layer, and the radius of the second sector being greater than or equal to the radius of the binding layer; and at least one current bridge connector, one end of the current bridge connector being connected to the outer peripheral surface of the superconducting coil, and the other end of the current bridge connector being connected to the first sector of the lead body.

Description

Technical Field

[0001] This invention relates to the field of superconducting magnet technology, and more specifically, to a superconducting coil current lead device. Background Technology

[0002] The superconducting coil current lead is a key channel component for realizing superconducting magnets.

[0003] However, existing superconducting coil current leads have problems such as high contact resistance, severe heat generation, damage to the coil's circular symmetry structure, uneven stress, and mechanical damage because the copper block is directly welded to the outer surface of the coil. Summary of the Invention

[0004] In view of this, the present invention provides a superconducting coil current lead device, comprising: at least one lead body disposed along the axial direction of the superconducting coil, the lead body including a first sector portion, a second sector portion and a connecting portion, the connecting portion being configured to connect the first sector portion and the second sector portion, the radius of the first sector portion being the same as the radius of the superconducting coil, a binding layer being wound around the outer peripheral surface of the superconducting coil, and the radius of the second sector portion being greater than or equal to the radius of the binding layer; and at least one current bridge connector, one end of the current bridge connector being connected to the outer peripheral surface of the superconducting coil, and the other end of the current bridge connector being connected to the first sector portion of the lead body.

[0005] According to an embodiment of the present invention, the lead body is made of a conductive material; wherein the second sector is configured to connect to an external power source, the external power source is configured to input an external current into the second sector, so that the external current is converged to the first sector via the connection portion and input to the superconducting coil via the current bridge connector.

[0006] According to an embodiment of the present invention, the lead body is made of an insulating material; wherein, a superconducting tape layer is laid on the outer peripheral surface of the lead body; or a groove is formed on the outer peripheral surface of the lead body, and the superconducting tape layer is embedded in the groove.

[0007] According to an embodiment of the present invention, the superconducting tape layer includes a first superconducting tape region and a second superconducting tape region. The first superconducting tape region extends to the outer peripheral surface of the first sector portion, and the second superconducting tape region extends to the outer peripheral surface of the second sector portion. The other end of the current bridge connector is connected to the first superconducting tape region. The second superconducting tape region is configured to connect to an external power source, which is configured to input external current into the second superconducting tape region so that the external current is transmitted through the superconducting tape layer to the first superconducting tape region and input to the superconducting coil via the current bridge connector.

[0008] According to an embodiment of the present invention, the central angle of the sector region covered by the orthographic projection of the first sector onto the surface of the superconducting coil is less than 180°.

[0009] According to an embodiment of the present invention, at least one of the aforementioned lead bodies is disposed adjacent to the first end face of the superconducting coil, and the first sector portion of each of the aforementioned lead bodies does not overlap with the sector area covered by the orthographic projection on the surface of the superconducting coil.

[0010] According to an embodiment of the present invention, at least one of the aforementioned lead bodies is rotationally symmetrical about the axis of the aforementioned superconducting coil.

[0011] According to an embodiment of the present invention, at least one of the aforementioned lead bodies includes a first lead body and a second lead body. The first lead body is disposed adjacent to a first end face of the superconducting coil, and the second lead body is disposed adjacent to a second end face of the superconducting coil. The fan-shaped area covered by the orthographic projection of the first fan-shaped portion of the first lead body onto the surface of the superconducting coil may partially overlap or not overlap with the fan-shaped area covered by the orthographic projection of the first fan-shaped portion of the second lead body onto the surface of the superconducting coil.

[0012] According to an embodiment of the present invention, the first lead and the second lead are centrally symmetrical about the geometric center of the superconducting coil.

[0013] According to an embodiment of the present invention, the current bridge connector comprises a single-layer or multi-layer stacked conductive structure, wherein the conductive structure comprises a superconducting strip, a braided copper strip, or a metal foil.

[0014] According to an embodiment of the present invention, by providing a lead body including a first sector, a second sector, and a connecting portion, and arranging the lead body along the axial direction of the superconducting coil, the lead body can be completely removed from the plane where the superconducting coil is located. This allows the superconducting coil to maintain a complete circular symmetrical shape, thereby enabling the binding layer wound around the outer periphery of the superconducting coil to apply force uniformly. This overcomes the problem of uneven clamping force caused by lead protrusion in traditional solutions, eliminating the risk of mechanical damage caused by stress concentration at its source. Furthermore, the radius of the first sector is the same as the radius of the superconducting coil, and the radius of the second sector is greater than or equal to the radius of the binding layer. This provides the lead body with radial contraction paths of inner and outer radii, thereby completing the spatial transition and current conduction across the binding layer. This design offers advantages such as a compact structure and the elimination of the need for additional bridging components, while ensuring the integrity of the binding layer and the uniformity of force application. Attached Figure Description

[0015] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings.

[0016] Figure 1 A schematic diagram of a planar welded current lead structure in the prior art is shown.

[0017] Figure 2 A schematic diagram of a superconducting coil current lead device in the prior art is shown.

[0018] Figure 3 A schematic diagram of a superconducting coil current lead device according to an embodiment of the present invention is shown.

[0019] Figure 4 A schematic diagram of a superconducting coil current lead device according to another embodiment of the present invention is shown.

[0020] Figure 5 A schematic diagram of a superconducting coil current lead device according to another embodiment of the present invention is shown.

[0021] Figure 6 A schematic diagram of a superconducting coil current lead device according to another embodiment of the present invention is shown. Detailed Implementation

[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0023] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms "comprising," "including," etc., as used herein indicate the presence of the above-described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0024] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0025] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0026] Figure 1 A schematic diagram of a planar welded current lead structure in the prior art is shown.

[0027] like Figure 1 As shown, in existing technologies, to introduce a large external current into a superconducting coil, the current lead structure typically includes a highly conductive oxygen-free copper block. This oxygen-free copper block acts as a physical bridge for current to be introduced into the superconducting coil from an external power source. One surface of the copper block is machined into a theoretical arc, intended to be welded to the outer circumference of the coil. A plane of the oxygen-free copper block is directly soldered to the outer circumference of the disc-shaped coil wound from superconducting strip, serving as a lead transition block. This is a planar welding method, where the copper block is directly soldered to the outer circumference of the coil within the same plane as the superconducting coil. However, this planar welding method partially interrupts the circular outline of the coil. The current is introduced into the coil within a single plane via a radial path: "copper block—welding interface—outer surface of the superconducting coil".

[0028] However, the above-mentioned planar welded current lead structure has the following fundamental defects in both electrical and mechanical aspects.

[0029] First, poor structural matching leads to excessively high contact resistance. Contact resistance refers to the additional resistance caused by incomplete actual bonding (the presence of numerous micron-level air gaps) when current flows through the welding interface between the copper block and the coil. Current can only pass through a few microscopic contact points, and the channel contraction increases local resistance. Due to limitations in the dimensional tolerances of the superconducting tape and the precision of the winding process, the wound superconducting coil is not an ideal standard circle. Its actual outer circumference has localized unevenness and inconsistent diameters; that is, the wound superconducting coil is not a perfect circle. Influenced by tape tolerances and the winding process, its outer circumference has local undulations and radius deviations, preventing the theoretically sized rigid copper block from fully bonding. The oxygen-free copper block, being a rigid solid, typically has its concave arc surface machined according to the theoretical arc, and cannot adapt to the coil's shape and position deviations. This inevitably results in a large number of randomly distributed air gaps at the bonding interface, with the effective conductive area being much smaller than the macroscopic contact area. When current passes through, it is forced to concentrate at the local micro-point contact point, resulting in a contact resistance much higher than expected. This exacerbates Joule heating, forming local hot spots, which poses a serious risk of quenching to the temperature-sensitive superconducting coil.

[0030] Second, mechanical failure occurs due to disruption of the coil's circular symmetry structure. A current-carrying coil in a strong magnetic field experiences a radially outward electromagnetic force, known as the Lorentz force. This force must be balanced structurally through a uniform circumferential path; otherwise, stress concentration and mechanical damage will occur. A circular symmetry structure represents the ideal circular shape where the outer circumference of the superconducting coil's cross-section remains continuous without abrupt changes. In this configuration, the enormous electromagnetic force experienced by the superconducting coil in a magnetic field can be transformed into a uniformly distributed circumferential stress. This is the safest stress distribution for brittle superconducting tapes and the optimal bearing condition for superconducting coils to withstand the enormous Lorentz force in strong magnetic fields, ensuring a uniform circumferential stress distribution. Current solutions embed copper blocks into the coil's outer contour, creating a localized asymmetric additional mass and abrupt change in stiffness.

[0031] Furthermore, in the structure of a superconducting magnet, to resist the enormous electromagnetic expansion force inside the superconducting coil when energized, a binding layer must be applied around the superconducting coil to form a clamp. The width of this binding layer is typically tens of millimeters, and its presence completely encloses the internal superconducting coil. This means that external power supply must be introduced into the superconducting coil via a current lead device that crosses this clamp structure. In other words, a binding layer needs to be added to the existing current lead structure to form the superconducting coil current lead device.

[0032] Figure 2 A schematic diagram of a superconducting coil current lead device in the prior art is shown.

[0033] like Figure 2 As shown, an oxygen-free copper block is soldered to the outer surface of the superconducting coil as a lead transition block. One side of this copper block is machined into a concave arc surface that matches the theoretical outer diameter of the superconducting coil. The current path is "external power source—copper block body—solder interface—outer surface of superconducting coil". Viewed from the side, the entire electrical connection is in the same radial plane as the coil. In other words, it uses a rigid conductive block that is attached and fixed in a plane to achieve current conduction across the binding layer.

[0034] However, due to the defects of the planar welded current lead structure mentioned above, the above technical solution also has the following two defects.

[0035] First, there are electrical defects in the interface bonding. Due to the tolerances of the superconducting tape and the winding precision, actual superconducting coils are not perfectly circular; the outer circumference has localized roundness errors and diameter fluctuations. The superconducting tape, the raw material used to manufacture the superconducting coil, is a composite thin strip containing superconducting ceramics. Its superconducting layer is a brittle oxide, mechanically extremely sensitive to stress concentration, and prone to fracture and loss of superconductivity due to minute deformation. The curved surface of the copper block is a rigid body machined to theoretical dimensions and cannot conform to the actual coil surface, resulting in numerous tiny local gaps between them. Current can only pass through a few contact points, causing increased contact resistance.

[0036] Secondly, it mechanically disrupts the circular symmetry of the superconducting coil. The copper block attached to the outer circumference of the coil causes a geometrical abrupt change in the originally smooth and continuous circular outline. This abrupt change forces the binding layer to apply force only around the non-circular combination of the coil and the protruding copper block, resulting in uneven adhesion between the binding layer and the coil, creating local gaps and ultimately uneven distribution of the clamping force. Under high-field excitation, stress concentration points are prone to causing mechanical damage to the brittle superconducting tape. This leads to two chain reactions: First, it disrupts the circumferential continuity of the coil body. During subsequent binding processes, the pre-tightening force of the binding tape is transmitted to the coil through the copper block, generating a non-uniform pressure field, resulting in local overpressure or insufficient support. Second, under high-field excitation, electromagnetic forces cause complex stress concentrations in the asymmetric structure, easily inducing microcracks or even fractures at weak interfaces of the superconducting tape (usually brittle ceramic oxide), making the current lead connection a "weak point" for magnet operation. Simply increasing the contact area or modifying the shape of the copper block does not change the fundamental pattern of "rigid embedding in the same plane", and therefore cannot eliminate the risks caused by the aforementioned asymmetry from a mechanistic perspective.

[0037] Therefore, a superconducting coil current lead device is needed to ensure that the superconducting coil maintains a complete circular symmetrical shape and to ensure the integrity of the binding layer and the uniformity of the applied force.

[0038] Figure 3 A schematic diagram of a superconducting coil current lead device according to an embodiment of the present invention is shown.

[0039] like Figure 3 As shown, the superconducting coil current lead device includes a lead body 310 and a current bridge connector 320. The lead body 310 includes a first sector 311, a second sector 312, and a connecting part 313.

[0040] The lead body 310 is arranged along the axial direction of the superconducting coil 340, and the connecting part 313 is configured to connect the first sector 311 and the second sector 312. The radius of the first sector 311 is the same as the radius of the superconducting coil 340. A binding layer 330 is wound around the outer peripheral surface of the superconducting coil 340, and the radius of the second sector 312 is greater than or equal to the radius of the binding layer 330.

[0041] The lead body 310 is the main current transmission component of the superconducting coil current lead device, and it adopts a non-circular variable-diameter structure with an outer radius (corresponding to the second sector 312) and an inner radius (corresponding to the first sector 311). The inner radius of the lead body 310 is equal to the outer diameter of the superconducting coil 340. The outer radius of the lead body 310 is greater than or equal to the outer diameter of the binding layer 330. The function of the lead body 310 is to provide a radial conductive path, allowing current to converge from the outer edge of the binding layer 330 inward to a position with the same diameter as the superconducting coil 340.

[0042] like Figure 3 As shown, the lead body 310 and the superconducting coil 340 are stacked on each other in the axial direction, but they are not on the same height plane. Figure 3 In the example front view, the lead body 310 is located above the superconducting coil 340. Depending on the actual needs, the lead body 310 can also be positioned below the superconducting coil 340. The binding layer 330 is radially wound around the outer periphery of the superconducting coil 340, and the outer diameter of the binding layer 330 is located in the region between the first sector 311 and the second sector 312.

[0043] The binding layer 330 is a structure used to achieve the binding function. Binding is a prestressed reinforcement process, in which high-strength steel strips or fibers are tightly wound around the outer circumference of the coil disc assembly to provide a uniform radial preload to resist the electromagnetic expansion force during excitation. This process requires that the outer circumference of the coil must be smooth and uniform; otherwise, the preload distribution will be severely uneven. The superconducting coil 340 can be a disc-shaped coil. A disc-shaped coil is a flat, circular coil unit made of superconducting strip wound in a spiral manner. It is a basic module for constructing large superconducting magnets, and the required magnetic field is obtained by stacking multiple coils along multiple axes.

[0044] One end of the current bridge connector 320 is connected to the outer peripheral surface of the superconducting coil 340, and the other end of the current bridge connector 320 is connected to the first sector 311 of the lead body 310.

[0045] The current bridge connector 320 can be made of an extremely thin, flexible material. Its function is to establish an electrical transition between the lead body 310 and the superconducting coil 340, and to adapt to the surface of the superconducting coil 340 using its own flexibility and thinness, without generating additional stress or disrupting the circular profile. The first sector 311 of the lead body 310 is electrically connected to the superconducting coil 340 through the current bridge connector 320, without direct rigid planar welding. That is, the current bridge connector 320 replaces the traditional rigid solder interface. One end of the current bridge connector 320 is connected to the first sector 311 of the lead body 310, and the other end is attached to the outer peripheral surface of the superconducting coil 340, completing the current transition in a flexible and extremely thin manner. The lead body 310 as a whole is not on the same plane as the superconducting coil 340 and the binding layer 330, and there is no physical embedding.

[0046] In an embodiment of the present invention, the current transmission path of the superconducting coil current lead device is as follows: the external current first enters the outer radius region of the lead body 310, i.e., the second sector 312, and then the external current is conducted to the inner diameter direction of the lead body 310 via the connecting part 313, and converges in the first sector 311 of the lead body 310, and then injected into the superconducting coil through the current bridge connector 320. This path realizes the transmission of current across the binding layer, while the lead structure is completely detached from the circular force-bearing contour of the coil, neither participating in the formation of the outer circle of the coil nor interfering with the uniform force application of the binding layer.

[0047] By moving the lead body 310 entirely out of the plane of the superconducting coil 340 and placing it on one side (upper or lower) of the axial direction of the superconducting coil 340, and using an extremely thin, flexible current bridge connector 320 (generally less than 0.3 mm thick) to achieve current transfer from the lead body 310 to the superconducting coil 340. The current bridge connector 320 can fit against the surface of the superconducting coil 340 without interfering with the original circular outline; at the same time, the lead body 310 itself adopts a non-circular structure with varying diameter. The first sector 311, as the smaller circle side, matches the outer diameter of the superconducting coil 340, and the second sector 312, as the larger circle side, matches the outer diameter after binding. Thus, the lead body 310 is moved out of the plane where the superconducting coil is located. Power supply across the binding layer is achieved through axial stacking and flexible transition, thereby completely avoiding the destruction of the circular symmetry structure of the coil. While completing the conduction function across the binding layer 330, it neither participates in the formation of the coil's roundness nor hinders the uniform application of force to the binding layer 330.

[0048] Through embodiments of the present invention, by providing a lead body comprising a first sector, a second sector, and a connecting portion, and arranging the lead body along the axial direction of the superconducting coil, the lead body can be completely withdrawn from the plane of the superconducting coil. This allows the superconducting coil to maintain a complete circular symmetrical shape, thereby enabling the binding layer wound around the outer periphery of the superconducting coil to apply force uniformly. This overcomes the problem of uneven clamping force caused by lead protrusions in traditional solutions, eliminating the risk of mechanical damage caused by stress concentration at its source. Furthermore, the radius of the first sector is the same as the radius of the superconducting coil, and the radius of the second sector is greater than or equal to the radius of the binding layer. This provides the lead body with radial contraction paths of inner and outer radii, thus completing the spatial transition and current conduction across the binding layer. This design offers advantages such as a compact structure and the elimination of the need for additional bridging components, while ensuring the integrity of the binding layer and the uniformity of force application.

[0049] In embodiments of the present invention, the geometry of the lead body is not necessarily limited to... Figure 3 The specific profile shown only needs to satisfy two constraints: the inner diameter of the lead body is equal to the radius of the superconducting coil, and the outer diameter of the lead body is greater than or equal to the outer diameter of the binding layer. Under these conditions, the lead body can be a complete variable diameter ring, a fan-shaped ring, or other irregular shapes, as long as it can form a radial conductive path from the outer diameter to the inner diameter.

[0050] The lead body, serving as the main current transmission component of the superconducting coil current lead device, can therefore be directly made of conductive material for conducting current. The second sector is configured to connect to an external power source, which inputs external current into the second sector. This external current is then converged to the first sector via a connecting portion and input to the superconducting coil via a current bridge connector. In embodiments of the invention, the material types of the lead body include, but are not limited to, oxygen-free copper, brass, aluminum alloy, or other high-strength metals.

[0051] Besides being used for direct current conduction in the lead body, a superconducting tape layer can also be incorporated into the lead body to achieve current transmission. In this case, the lead body can be made of insulating materials such as epoxy resin. Specifically, a superconducting tape layer is laid on the outer circumferential surface of the lead body; or a groove is formed on the outer circumferential surface of the lead body, and a superconducting tape layer is embedded in the groove. The superconducting tape layer includes a first superconducting tape region and a second superconducting tape region. The first superconducting tape region extends to the outer circumferential surface of the first sector, and the second superconducting tape region extends to the outer circumferential surface of the second sector. The other end of the current bridge connector is connected to the first superconducting tape region. The second superconducting tape region is configured to connect to an external power supply, which is configured to input external current into the second superconducting tape region so that the external current is transmitted through the superconducting tape layer to the first superconducting tape region and then input to the superconducting coil through the current bridge connector.

[0052] Figure 4 A schematic diagram of a superconducting coil current lead device according to another embodiment of the present invention is shown.

[0053] like Figure 4 As shown, the superconducting coil current lead device includes a lead body 310, a current bridge connector 320, and a superconducting tape layer 430. The lead body 310 itself is made of insulating material. A superconducting tape layer 430 is attached to the outer circumference of the lead body 310, connecting the inner and outer diameter regions of the lead body 310. The superconducting layer of the superconducting tape layer 430 faces outward and is in contact with the surface of the lead body 310. Through this arrangement, current can flow along the superconducting tape layer 430.

[0054] By laying a superconducting tape layer on the surface or in the groove of the lead body, the zero resistance characteristic of the superconducting tape is used to carry the transmission current. The lead body itself undertakes the structural support function, and the superconducting tape undertakes the conductivity function. This can also achieve lossless transmission of large current across the binding layer, further reduce the Joule heating of the lead body, and allow for flexible selection of the base material according to mechanical requirements.

[0055] According to an embodiment of the present invention, the central angle of the sector region covered by the orthographic projection of the first sector onto the surface of the superconducting coil is less than 180°.

[0056] In other words, the lead body does not need to cover the entire circumference of the superconducting coil. The central angle θ of the sector area covered by the orthographic projection of the first sector of the lead body onto the surface of the superconducting coil can be arbitrarily set between 0° and 180° according to the actual current capacity requirements or space arrangement requirements. When θ is small (e.g., 10°–30°), the superconducting coil current lead device is more compact and suitable for single-channel current introduction; when θ is large, it can provide a wider current path to reduce current density. This sector angle can be flexibly adjusted according to the number of leads and the current level.

[0057] In a specific embodiment of the present invention, the superconducting coil current lead device can also be implemented based on a multi-channel parallel scheme, specifically configured as follows: at least one lead body is disposed adjacent to the first end face of the superconducting coil, the first sector of each of the at least one lead body does not overlap with the sector area covered by the orthographic projection on the surface of the superconducting coil, and at least one lead body is rotationally symmetrical about the axis of the superconducting coil.

[0058] In other words, two or more leads can be arranged circumferentially around the superconducting coil, each occupying a different sector and spaced apart from the others. Each lead is connected to the superconducting coil through an independent current bridge connector. The parallel connection of multiple channels can effectively shunt current, reducing the current load on a single lead, while the circumferentially symmetrical arrangement can also make the superconducting coil more evenly stressed, further suppressing asymmetric stress.

[0059] Figure 5 A schematic diagram of a superconducting coil current lead device according to another embodiment of the present invention is shown.

[0060] like Figure 5 As shown, the superconducting coil current lead device includes a first lead body 511, a second lead body 512, a first current bridge connector 521, and a second current bridge connector 522. The fan-shaped area covered by the orthographic projection of the first fan-shaped portion of the first lead body 511 onto the surface of the superconducting coil and the fan-shaped area covered by the orthographic projection of the first fan-shaped portion of the second lead body 512 onto the surface of the superconducting coil do not overlap. The first lead body 511 is connected to the superconducting coil through the first current bridge connector 521, and the second lead body 512 is connected to the superconducting coil through the second current bridge connector 522. The first lead body 511 and the second lead body 512 introduce current in a multi-channel parallel configuration. This structural arrangement effectively shunts the current and reduces the current load on a single lead body.

[0061] In one specific embodiment of the present invention, the superconducting coil current lead device can also be configured as an axially symmetrical structure. Specifically, at least one lead body includes a first lead body and a second lead body. The first lead body is disposed adjacent to a first end face of the superconducting coil, and the second lead body is disposed adjacent to a second end face of the superconducting coil. The fan-shaped area covered by the orthographic projection of the first fan-shaped portion of the first lead body onto the surface of the superconducting coil partially overlaps or does not overlap with the fan-shaped area covered by the orthographic projection of the first fan-shaped portion of the second lead body onto the surface of the superconducting coil. The first lead body and the second lead body are centrally symmetrical about the geometric center of the superconducting coil. That is, the first lead body and the second lead body are simultaneously disposed above and below the superconducting coil, forming a symmetrical lead structure. The first lead body and the second lead body each cover the same or different fan-shaped areas, and power is fed to the superconducting coil through the first current bridge connector and the second current bridge connector corresponding to the first lead body and the second lead body, respectively. By using the above-mentioned axially symmetrical scheme, current shunting can be achieved while forming a symmetrical structural constraint on the superconducting coil in the axial direction, eliminating the small overturning torque that may be introduced by the single-sided lead.

[0062] Figure 6 A schematic diagram of a superconducting coil current lead device according to another embodiment of the present invention is shown.

[0063] like Figure 6 As shown, the superconducting coil current lead assembly includes a third lead body 611 and a fourth lead body 621. Overall, the third lead body 611 and the fourth lead body 621 are simultaneously positioned above and below the superconducting coil and are centrally symmetrical about the geometric center of the superconducting coil, forming a double-sided symmetrical lead structure. To meet the requirements for compliant attachment at different current levels, the current bridge connector can also be configured as a single-layer or multi-layer stacked conductive structure, including superconducting tape sheets, braided copper tapes, and metal foils. Furthermore, the thickness, number of layers, and width of the conductive structure can be adjusted according to the magnitude of the transmitted current.

[0064] In summary, the embodiments of the present invention have the following technical effects.

[0065] First, it can overcome poor interface adhesion, reduce contact resistance, and reduce heat generation. In existing planar welding schemes, the rigid copper block's curved surface cannot fit tightly against the surface of the superconducting coil, which has roundness errors, resulting in numerous micro-gaps. This leads to increased contact resistance and concentrated Joule heat. By setting one end of a current bridge connector to the inner diameter edge of the lead body and the other end to fit against the surface of the superconducting coil, the current bridge connector, being a flexible and extremely thin conductive connector, possesses excellent compliant deformation capabilities. Therefore, it can adapt to the roundness deviation and local diameter fluctuations of the actual outer circle of the superconducting coil, fitting conformally rather than forcibly matching with a pre-set fixed curved surface like a rigid copper block. This characteristic makes the actual conductive contact area on the welding or pressing interface significantly closer to the macroscopic contact area. The current does not need to contract and concentrate to pass through a few discrete micro-protrusions, thus effectively eliminating the unavoidable micron-level gaps in traditional rigid contact interfaces, significantly reducing contact resistance, and consequently greatly reducing Joule heat during current transmission. This suppresses the formation of local hot spots, reduces the risk of superconducting coil quenching due to temperature rise, and improves the device's current carrying capacity and operational thermal stability.

[0066] Secondly, it eliminates structural asymmetry, ensuring uniform binding and mechanical safety. In existing solutions, the copper block is embedded in the outer circular plane of the superconducting coil, disrupting the coil's circular symmetry. This results in uneven force application to the binding layer, leading to stress concentration and potential mechanical damage to the superconducting tape under high fields. This invention uses a coaxial stacking arrangement of the lead wire and superconducting coil, positioned at different heights. The lead wire does not participate in forming the outer periphery of the superconducting coil. This arrangement completely removes the conductive lead wire from the radial plane of the superconducting coil, maintaining its outer circumference as a continuous, smooth, and geometrically abrupt complete circle. In subsequent binding processes, the binding layer can be directly wound around this complete circular contour. The preload is uniformly transmitted along the circumference to the surface of the superconducting coil, no longer blocked or deflected by any lead wire components. The enormous Lorentz force experienced by the superconducting coil under high fields is thus distributed to each cross-section of the tape in an ideal, uniform circumferential tensile stress manner. Therefore, the uneven distribution of clamping force caused by the protrusion of the lead body in traditional solutions and the resulting stress concentration problem can be eliminated at the source. Since the stress level at any point of the brittle superconducting tape tends to be uniform, the safety margin is maximized, thereby eliminating the risk of crushing or frictional heating and fatigue fracture caused by insufficient support due to local overpressure, and significantly improving the mechanical reliability and long-term stability of the magnet operation.

[0067] Third, the design decouples the lead wire and binding functions, resulting in a compact structure and good process compatibility. In existing solutions, the lead wire copper block and the binding layer coexist on the same outer surface of the superconducting coil. The lead wire structure disrupts the continuity of binding, while the binding restricts the lead wire arrangement, causing mutual interference. In this invention, the lead wire body has an inner radius and an outer radius. The inner radius of the lead wire body is equal to the outer diameter of the superconducting coil, and the outer radius of the lead wire body is greater than or equal to the outer diameter of the binding layer. Furthermore, the entire lead wire body can be flexibly arranged above or below the superconducting coil. Based on the radial dimension design of the lead wire body, it forms an independent transition path from the outer edge of the binding layer to the inner edge of the coil. Current is conducted from the outside to the inside along its body, while the binding layer completely covers the outer periphery of the superconducting coil. The two are arranged in layers in radial space without intruding into each other's space. The axial stacking installation method means that the setting of the lead wire body does not require fundamental changes to the existing coil winding and binding process. Therefore, the lead body and binding structure are spatially and functionally decoupled, preventing interference between them. This results in a compact superconducting coil current lead device that requires no additional radial bridging components. Furthermore, this superconducting coil current lead device can be flexibly placed above or below the coil depending on the actual assembly space, and the fan-shaped coverage angle can be adjusted according to current rating requirements. It exhibits strong engineering adaptability and is easy to promote in existing magnet manufacturing processes.

[0068] Those skilled in the art will understand that the features described in the various embodiments of the present invention can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention can be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.

[0069] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A superconducting coil current lead device, characterized in that, include: At least one lead body is arranged along the axial direction of the superconducting coil. The lead body includes a first sector, a second sector, and a connecting portion. The connecting portion is configured to connect the first sector and the second sector. The radius of the first sector is the same as the radius of the superconducting coil. A binding layer is wound around the outer peripheral surface of the superconducting coil. The radius of the second sector is greater than or equal to the radius of the binding layer. At least one current bridge connector, one end of which is connected to the outer peripheral surface of the superconducting coil, and the other end of which is connected to the first sector of the lead body.

2. The superconducting coil current lead device according to claim 1, characterized in that, The lead body is made of a conductive material; The second sector is configured to be connected to an external power source, which is configured to input external current into the second sector so that the external current is converged to the first sector via the connection portion and input to the superconducting coil via the current bridge connector.

3. The superconducting coil current lead device according to claim 1, characterized in that, The lead body is made of insulating material; The lead body has a superconducting tape layer laid on its outer peripheral surface; or a groove is formed on the outer peripheral surface of the lead body, and the superconducting tape layer is embedded in the groove.

4. The superconducting coil current lead device according to claim 3, characterized in that, The superconducting tape layer includes a first superconducting tape region and a second superconducting tape region, wherein the first superconducting tape region extends to the outer peripheral surface of the first sector portion, and the second superconducting tape region extends to the outer peripheral surface of the second sector portion; The other end of the current bridge connector is connected to the first superconducting strip region; The second superconducting tape region is configured to be connected to an external power source, which is configured to input an external current into the second superconducting tape region so that the external current is transmitted through the superconducting tape layer to the first superconducting tape region and input to the superconducting coil through the current bridge connector.

5. The superconducting coil current lead device according to claim 1, characterized in that, The central angle of the sector area covered by the orthographic projection of the first sector onto the surface of the superconducting coil is less than 180°.

6. The superconducting coil current lead device according to claim 1, characterized in that, At least one of the lead bodies is disposed adjacent to the first end face of the superconducting coil, and the first sector of each of the at least one lead body does not overlap with the sector area covered by the orthographic projection on the surface of the superconducting coil.

7. The superconducting coil current lead device according to claim 6, characterized in that, At least one of the lead bodies is rotationally symmetrical about the axis of the superconducting coil.

8. The superconducting coil current lead device according to claim 1, characterized in that, At least one of the lead bodies includes a first lead body and a second lead body, wherein the first lead body is disposed adjacent to a first end face of the superconducting coil, and the second lead body is disposed adjacent to a second end face of the superconducting coil, wherein the fan-shaped area covered by the orthographic projection of the first fan-shaped portion of the first lead body on the surface of the superconducting coil partially overlaps or does not overlap with the fan-shaped area covered by the orthographic projection of the first fan-shaped portion of the second lead body on the surface of the superconducting coil.

9. The superconducting coil current lead device according to claim 8, characterized in that, The first lead and the second lead are centrally symmetrical about the geometric center of the superconducting coil.

10. The superconducting coil current lead device according to claim 1, characterized in that, The current bridge connector includes a single-layer or multi-layer stacked conductive structure, which includes superconducting tape sheet, braided copper tape, or corrugated metal foil.

Images