Patent Application
20180226730
The invention relates to a connector for superconductive conductors and to a use of the connector.
Superconductors are materials whose electrical resistance completely disappears below a certain temperature, the transition temperature. Consequently, superconductors have no electrical DC losses if operated at sufficiently low temperatures. Consequently, a conductor for carrying electricity or a coil of such superconductive materials has no DC losses. Thus, current can be transmitted very effectively through such a conductor. In particular, high magnetic fields can be generated very efficiently using superconductive magnets. A distinction is made between low-temperature and high-temperature superconductors according to the value of the temperature of the phase transition from the superconductive to the normally conducting state. In low-temperature superconductors, it is typically below 30 K, in high-temperature superconductors in some cases very clearly higher, e.g. above the boiling point of nitrogen (T=−196° C.). Therefore, high-temperature superconductors (HTS) are also under discussion with regard to further applications, because—compared to low-temperature superconductors—the effort of cooling is significantly reduced. These include, among others, the energy transmission, rotating machines, such as generators, motors, etc., or magnets, e.g. for particle accelerators.
High-temperature superconductors of rare earth barium copper oxide materials (shortly REBCO), in view of the field and temperature ranges as well as the current density, are the most interesting HTS materials currently available on the market. These materials are produced in the form of thin strips or ribbons, in which the superconductor is deposited onto a substrate as a thin layer having a thickness of about 1 μm, so that a strip having a typical thickness of 100 μm is formed with a width in the millimeter range. For these fiat strips, it is not possible to use classic stranding techniques for the production of superconductive conductors or cables of high current-carrying capacity.
Instead, in recent approaches, stacks of superconductive strips or ribbons are produced in order to manufacture electrical conductors or cables for higher currents from the superconductive conductors.
In the transmission of high electrical power through superconductors, the conductors must be cooled accordingly. In order to achieve high current densities in the bundle or cable, they must be as compact as possible. At the same time, however, high mechanical stability is necessary as well, e.g. with regard to mechanical support with minimal heat input, thermal cycles or electromagnetic forces.
To use such superconductive conductors or cables in applications, however, not only the conductors themselves, but also electrical connectors with which the superconductive conductors can be assembled or connected, are crucial as well. In particular, it is important with such superconductive conductors that an electrical is connector resistance and/or connection resistance resulting from the connection is as low as possible or negligible. Connector resistance as used in this specification particularly is understood to be the electrical resistance of the connector itself. The sum of the connector resistance and possibly occurring contact resistances between the conductors and the connector will be referred to as connection resistance below.
Conventionally, the individual superconductor strips of a superconductive conductor or cable are individually contacted with the superconductor strips of another superconductive conductor or cable. However, this is very time-consuming and expensive and therefore not suitable for industrial purposes.
Another known way to connect superconductive cables to each other is the so-called lap-joint connection. Here, the superconductive conductors are soldered e.g. in a copper block such that the ends of the conductors to be connected overlap. Due to the overlap, the current can flow directly from one conductor into another over the entire soldered-in length of the superconductive conductors. Depending on the degree of overlap, the electrical connector resistance can be kept low.
However, the conventional solutions have drawbacks. For example, it is very time-consuming to establish direct connections of the individual superconductor strips. In addition, such connections may be relatively unstable. In the lap-joint connections, the greatest possible overlap of the conductors to be connected is advantageous to reduce the connector resistance. However, this comes at the expense of compactness. In addition, the conventional connecting methods and connectors are very inflexible in use, particularly during laying of superconductive conductors or cables. A flexible connection and laying of superconductive conductors or cables plays an important role especially because the superconductor stacks, from which the conductors or cables are usually made, can be bent only to a very limited extent.
It is therefore an object of the present invention to provide a connector for superconductive conductors or cables, which is compact, easy to handle and flexible in use.
This object is solved by the subject matters of the independent claims. Advantageous is embodiments are subject of the subclaims.
A first independent aspect for achieving the object relates to a connector for electrically connecting at least a first superconductive conductor with at least one second superconductive conductor, comprising:
The base element or the base body of the connector is primarily the mechanical connection or intermediate piece between the superconductive conductors or cables to be electrically connected. However, the base element is also electrically conductive, i.e. at least normally conductive. Preferably, the base element is formed at least partially or entirely from a conductive metal, such as copper, aluminum or silver. For example, the base element is a copper block. The base element has a first end portion or first end and a second end portion or second end. The first end portion or first end of the base element is adapted to be contacted, i.e. to be electrically connected, with at least a first superconductive conductor or cable. For example, the first end portion can be contacted with one, two, three, four, etc. first superconductive conductors. Correspondingly, the second end portion or second end of the base element is also s adapted to be contacted, i.e. to be electrically connected, with at least a second superconductive conductor or cable. For example, the second end portion can be contacted with one, two, three, four, etc. second superconductive conductors. In particular, each end portion of the connector or of the base element can have one or more intended contact points for contacting one or more superconductive conductors or cables.
First and second conductors as defined in this specification mean two conductors to be electrically connected. Contacting means electrically connecting, in particular thermally joining or soldering or also pressing in suitable materials, such as indium.
The at least one first and the at least one second conductor are not part of the connector according to the invention. Only in an assembled state of the connector is the at least one first conductor connected to the first end portion of the connector and/or is the at least one second conductor connected to the second end portion of the connector.
The at least one superconductive additional element preferably comprises a superconductor or a superconductive strip, and most preferably a high-temperature superconductor or a high-temperature superconductive strip, so that with appropriate cooling, i.e. at temperatures below the transition temperature of the superconductor, there is a superconductive electrical connection between the first end portion and the second end portion of the connector. In other words, the at least one superconductive additional element is arranged in such a way that, below the transition temperature of the superconductive additional element, it connects the first end portion and the second end portion to each other in a superconducting manner. The at least one superconductive additional element thus acts as a superconductive bypass, which is why the connector according to the invention is referred to as “SC-ByPass Connector” by the inventors.
In the assembled state, the at least one superconductive additional element causes a substantially superconductive electrical connection between the at least one first superconductive conductor and the at least one second superconductive conductor. “Substantially superconductive” mean or should be considered such that, where appropriate, contact resistances are possible at the contact points between the conductors and the connector.
The at least one superconductive additional element in particular is not part of a conductor to be connected, but is a separate part of the connector according to the invention, in other words, the at least one superconductive additional element is integrated in the connector independently of the conductors to be connected. The at least one superconductive additional element is arranged or integrated in the base element at least in part(s). Here, the term “at least in part(s)” includes the terms “partially”, “in portions” or “completely”, in particular, the at least one superconductive base element is arranged within the base element, in particular in a groove, a recess or in a cavity of the base element, at least in part(s).
The at least one superconductive additional element in the connector according to the invention has the advantageous effect that when two or more conductors are connected, the current does not have to flow through the base element over the entire distance, but via the at least one additional element, which at sufficiently low temperatures, i.e. temperatures below the transition temperature of the additional element, has no electrical resistance. Thus, the electrical resistance of the connector can be largely minimized or neglected. Moreover, no overlap of the conductors to be connected is necessary, so that the connector according to the invention can be very compact.
Unlike conventional types of connections, which usually are based on contacting the individual superconductor strips of the conductors to be connected individually, advantageous contacts between a whole conductor or cable can be realized by the inventive connector. Such contacts are easy to establish and are therefore also suitable for industrial use.
It is understood that the connector according to the invention is suitable not only for electrically connecting superconductive conductors or cables, but also for connecting any other, in particular normally conducting conductors or cables.
in a preferred embodiment, the base element has at least one recess or groove, in which the at least one superconductive additional element is arranged at least in part(s). Alternatively or additionally, the at least one superconductive additional element is connected to the base element in electrical contact therewith, or is electrically connected to the base element. For example, the superconductive additional element is inserted, pressfitted and/or soldered into the recess or groove. The groove may be arranged or formed on a surface or outside of the base element. A recess may be arranged or formed in inside the base element, in particular as a through opening from the first to the second end portion.
In a further preferred embodiment, the base element comprises several base element parts. In other words, the base element may be composed of several base element parts. In the mounted or assembled state of the connector, the entirety of the base element parts constitutes the base element. In particular, the base element parts may be formed such that in the assembled state of the connector, between two base element parts, a groove or recess is formed in the base element.
Alternatively or additionally, the base element comprises a joint or hinge. In this way, it is advantageously possible to bend the base element and the connector in a simple manner.
Alternatively or additionally, the base element is formed partially or completely of copper. For example, the base element comprises one or more copper blocks. En particular, the base element may be a copper block.
Alternatively or additionally, the at least one superconductive additional element comprises or is at least one superconductor strip, in particular a high-temperature superconductor strip. Preferably, the at least one superconductive additional element comprises a stack of superconductor strips or the at least one superconductive additional element is a stack of superconductor strips.
A superconductor strip is a strip comprising a substrate, on which a superconductor, especially a high-temperature superconductor such as REBGO, is applied as a thin layer, for example with a thickness of about 1 μm. The substrate may have a thickness of about 100 μm. A superconductor strip thus also has a thickness of about 100 μm, for example, and may have a width of several millimeters.
In a further preferred embodiment, the base element comprises several base element parts or base element portions, which in particular are movable into each other in order to compensate for changes in length, wherein a length of the at least one superconductive additional element is greater than the sum of the lengths of the base element parts. In other words, a length of the at least one superconductive additional element is greater than a length of the base element. For example, the at least one superconductive additional element may be arranged around the base element in an arcuate manner, in particular in a central portion of the connector. In other words, the at least one superconductive additional element may be formed or bent in a C-shape, in particular in a central portion of the connector. Preferably, the bent portion of the at least one superconductive additional element has a radius of >1 cm. Thus, it can be ensured that the at least one superconductive additional element or its superconductor strip(s) is/are bent substantially degradation-free and thus continue(s) to transmit the current in case of angular changes or changes in length of the base element.
Preferably, the connector or the base element or at least one of the base element parts comprises a displacement groove, in which one or more base element parts are movable or displaceable. With the help of the groove, the base element or the connector is variable or adjustable in length.
In a base element comprising several base element parts, the at least one superconductive additional element or the at least one superconductive strip stack can be arranged or attached e.g. on the inside of the base element parts in a simple manner. Moreover, the conductors or cables to be connected to the connector can be contacted, particularly pressfitted or soldered with the end portions of the connector in a simple manner. The gap between cable and connector can be reduced and thus optimized in a simple manner.
In a further preferred embodiment, the connector or the base element is adapted to electrically connect n first superconductive conductors to n second superconductive conductors, wherein the connector comprises n or an integral multiple of n superconductive additional elements, and wherein n is a natural integer greater than zero. In particular, n is 1, 2, 3, 4, 5, etc.
In a further preferred embodiment, the at least one conductive base element and in particular also the at least one superconductive additional element is formed to be rectilinear or angled or bent. Alternatively or additionally, the at least one conductive base element and in particular also the at least one superconductive additional element is formed such that, in an assembled state of the connector, a longitudinal axis of at least one first superconductive conductor and a longitudinal axis of the at least one second superconductive conductor enclose or form an angle between 0° and 180°. Here, an angle of 0° means a rectilinear connector, and an angle of 180° means a U-shaped connector, for example.
In the assembled state, the first end portion of the base element is contacted or connected with at least a first superconductive conductor and/or the second end portion of the base element is contacted or electrically connected with at least a second superconductive conductor.
The shape of the connector, i.e. of the base element and/or of the superconductive additional element, can be customized so that straight connections and angled connections can be realized. Thus, it is not necessary to bend the superconductive conductor or the superconductive cable strongly. In currently available superconductive conductors, such bending, in particular due to the stacked superconductor single strips or the superconductor body of the conductors formed thereby, usually results in a degradation of the superconductor. Such degradation can be avoided with the connector according to the invention. Compared to superconductor stacks, superconductor single strips can be bent relatively strongly in one bending direction, for example in a radii of a few centimeters. Thus, when a superconductive additional element comprising a single or only a few superconductor strips is used, also strongly angled or bent connectors can be realized.
With the connector according to the invention, an arbitrary path or way, e.g. in pipes, ducts or shafts, can the laid out or laid with substantially rectilinear superconductive conductors and with the help of respective connectors or elbows according to the invention. You could see some resemblance to the laying water pipes, if the aspect of cooling is neglected: The connectors play the role of the press or solder fittings, the superconductive conductors play the role of the pipes.
A further independent aspect for achieving the object relates to a use of the connector according to the invention for connecting at least one first superconductive conductor with at least one second superconductive conductor.
Preferably, the at least one first and the at least one second superconductive conductor each comprise a plurality of superconductor strips, which are each arranged into a strip is stack and which each form a superconductor body of the respective superconductive conductor.
In particular, the at least one first superconductive conductor comprises a plurality of superconductor strips, which are arranged into a first strip stack and form a first superconductor body of the at least one first superconductive conductor. Correspondingly, the at least one second superconductive conductor comprises a plurality of superconductor strips, which are arranged into a second strip stack and form a second superconductor body of the at least one second superconductive conductor.
In particular, the superconductor body has a cross-shaped cross-section. In particular, the strip stack of superconductor body has superconductor strips with exactly two different widths.
In a preferred embodiment, the first end portion of the connector is electrically contacted with the superconductor body of the at least one first superconductive conductor. Alternatively or additionally, the second end portion of the connector is electrically contacted with the superconductor body of the at least one second superconductive conductor.
In a further preferred embodiment, the first end portion of the connector is electrically contacted with a cladding tube of the at least one first superconductive conductor. Alternatively or additionally, the second end portion of the connector is electrically contacted with a cladding tube of the at least one second superconductive conductor.
It is also possible to electrically contact the first end portion of the connector with both the cladding tube and the superconductor body of the at least one first superconductive conductor. Correspondingly, it is possible to electrically contact the second end portion of the connector with both the cladding tube and the superconductor body of the at least one second superconductive conductor.
In a further preferred embodiment, electrical contacting is achieved by pressfitting or thermal joining, in particular by connecting by means of heating or by soldering.
For the above-mentioned further independent aspect and in particular for corresponding preferred embodiments, the statements made above or below with regard to the embodiments of the first aspect apply as well. In particular, for an independent aspect of the present invention and for corresponding preferred embodiments, the statements made above or below with regard to the embodiments of the respective other aspects apply as well.
In particular, in the context of the present disclosure, a superconductive system comprising a first superconductive conductor, a second superconductive conductor and the connector according to the invention is provided as well. The connector is used in particular for electrically connecting the first and second superconductive conductors. In particular, the connector connects the first superconductive conductor with the second superconductive conductor electrically. In particular, the first and/or the second superconductive conductor or the strip stack or the superconductor body of the first and/or second superconductive conductor, as described above and/or below, has a cross-shaped cross-section. The cross-shaped cross-section is in particular realized in that the superconductor body is formed of a strip stack, which exclusively has strips with two different widths or exclusively consists of strips with two different widths.
In the following, individual embodiments for achieving the object will be described by way of example on the basis of figures. Here, the individual embodiments described partly have features that are not necessarily required to carry out the claimed subject matter, but which in certain applications provide desired properties. Thus, embodiments not including all the features of the embodiments described in the following should be considered to be disclosed by the technical teaching as well. Further, to avoid unnecessary repetition, certain features are only mentioned with respect to individual embodiments described below. It is pointed out that the individual embodiments should not be considered in an isolated way only, but also in combination. The skilled person will recognize from this combination that individual embodiments may also be modified by incorporating single or multiple features of other embodiments. It should be noted that a systematic combination of the individual embodiments with individual or several features described with respect to other embodiments may be desirable and useful and therefore should be taken into consideration and regarded as included in the specification.
As shown in
Alternatively to the lap-joint connection, the superconductor of the first conductor 10 and the superconductor of the second conductor 20 are conventionally split up into individual components and then connected to each other individually.
The connector 100 comprises a base element 30 and at least one superconductive additional element 40. In the example of
In the example of
In the example of
As also shown in
As can be seen in the detailed views of
It is understood that other embodiments, in which the connector 100 or the base element 30 comprises a plurality of base element parts, are possible as well. For example, the base element may comprise one, two, three, four, five, etc., base element parts. The number and arrangement of superconductive additional elements 40 may vary.
The conductors or cables 10 and 20 each have a cladding tube 80, which surrounds the superconductor body 50. Both the superconductor body 50 and the cladding tube 80 can be contacted with the end portions of the connector 100. In particular, the cable ends can be placed between the base element parts 30g and 30h and then be connected, in particular soldered and/or pressed thereto.
In the angled connector 100, the superconductive additional elements or the superconductor strips are all oriented in the same plane in order to lead them along their easy bending axis about the 90° angle in a degradation-free manner.
In the embodiment of
In the embodiment of
The superconductive additional elements or superconductor strips 40 extending through the connector are bent in a C-shape in the central portion of the connector 100. Therefore, the superconductive strips preferably have a C-shaped curve with a radius of >1 cm, so that bending of the superconductor remains degradation-free in this way and the current can still be transmitted in the case of changes in length of the base body.
The cross section of the connector 100 is preferably selected such that in the quench case, the current can flow via the base element 30 or the base element parts until cut-off.
The connector 100 of the invention can thus he used for connecting at least one first superconductive conductor with at least one second superconductive conductor. Here, the at least one first and the at least one second superconductive conductor can each comprise a plurality of superconductor strips, which are each arranged into a strip stack and each form a superconductor body of the respective superconductive conductor.
The end portions 32 and 34 of connector 100 can each be contacted with the superconductor body 50 of a superconductive conductor or cable. A superconductive conductor may also comprise a cladding tube 80. In particular, the superconductor body 50 of a superconductive conductor may be surrounded by a cladding tube 80. This cladding tube 80 may also be contacted at an end portion 32, 34 of the connector 100. In this way, a connection or contact is possible in a very simple and stable manner.
The connector 100 of the invention and the associated modular connection concept, i.e. provision of a plurality of connectors with different angles d, allows easy technical usability of superconductive conductors or cables even with complex geometries. With the help of the connector 100, the superconductive conductors can be laid analogous to a water pipe. Here, the connector plays the role of a press or solder fitting, while the superconductive conductors or cables play the role of pipes to be connected.
1 superconductor strip
2 superconductor strip
5 superconductor strip
10 first superconductive conductor or first superconductive cable
15 intermediate piece/copper block
20 second superconductive conductor or second superconductive cable
30 base element/copper block
30
a part of the base element
30
b part of the base element
30
c part of the base element
30
d part of the base element
30
e heating and pressing device
30
f heating and pressing device
30
g part of the base element
30
h part of the base element
30
i part of the base element
30
j part of the base element
30
k part of the base element
30
l part of the base element
32 first end portion/first end
34 second end portion/second end
37 joint/hinge
40 superconductive additional element
50 superconductor stack/superconductor body
80 cladding tube
100 connector
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2015 010 634.1 | Aug 2015 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2016/001370 | 8/10/2016 | WO | 00 |
