EP1817781B1 - Inductive component and method for the production of such an inductive component - Google Patents

Description

The invention relates to an inductive component having a conductor with a non-rectangular cross-section for conducting a current, at least one flat connection conductor for supplying or discharging the current to or from the conductor, wherein the conductor and the connection conductor in the region of a connecting portion of Conductor are connected together to form a conductor arrangement. More particularly, the invention relates to an inductive component having a magnetic module with an opening, wherein the current conductor is passed through the opening.

The invention also relates to a method for producing a conductor arrangement for such an inductive component.

For current detection various types of electronic electricity meters are known, which increasingly replace the mechanical Ferrari counters in the industrial and household sector and carry out the current detection with differently constructed arrangements. In addition to current detection with measuring shunts, Rogowski coils or Hall elements, current transformers based on soft-magnetic toroidal cores, in particular toroidal cores, are also widely used as magnetic modules in electronic meters. A magnetic module (current transformer, transformer) provides galvanic isolation and provides a precise measure in the form of a signal voltage at a load resistor. The requirements for amplitude accuracy, phase accuracy and linearity are defined by IEC 62053, -21, -23 or formerly 1036 in Europe and ANSI C12.xx in the USA, and are, for example, in the company brochure "VAC Current Transformers for Electronic Energy Meters", Vacuumschmelze, October 1998 refer. Current transformer for Electronic energy meters are also generally known from the company brochure "Current transformers for electronic energy meters" of Vacuumschmelze 2002. Such energy converters using energy meters (also called Watthour meter) serve as officially approved measuring means to account for the electricity used by a consumer in terms of cost to the energy utility companies.

Known is a structure of busbars and a matching toroidal current transformer for detecting consumption currents in electronic energy meters. Pluggable electricity meters widely used in the USA and other countries have standardized rectangular connection lugs on the back, which are inserted into slots with suitable spring contacts when the electricity meter is mounted. These connections with a cross section of about 2.5 mm ax serve induction and recovery of the consumption current which at 110 V systems is a maximum of about 200-480 A _eff. As the thickness a of the cross-section, for example, a = 19 mm is set at a maximum current of I-max = 320A. Typically, the currents of the three phases of the AC mains are fed into the electricity meter, through a current sensing system, and out of the electricity meter again. An electronic circuit in the electricity meter detects the currents of the three current detection systems and calculated from current and phase the energy consumed, such as from US 4,887,028 is known.

The currently cheapest production of a magnetic component for high-quality current transformers consists in the production of toroidal cores, in particular toroidal cores, and the winding of the isolated or encapsulated cores with the corresponding secondary winding on the basis of enameled copper wire. Cores suitable for this purpose are known, for example, from US Pat EP 1 131 830 and EP 1 129 459 , The EP 1 114 429 describes current transformers for such purposes.

One way of constructing a current transformer is to select the size of the current transformer so that it is possible to pass through a bus bar, for example, the size of 19 x 2.5 mm through the inner hole of the current transformer.

An optimization is to give the area of the busbar on which the current transformer is to sit, a round cross-section. As a result, the inner hole of the current transformer can be smaller and used as a result of a smaller ring band core, which is due to the process then cheaper accordingly. Even with the same use of soft magnetic strip material and the same winding time for the core, the smaller the diameter of the core, the more favorable are the process steps of a heat treatment and a coating. The production of a suitable busbar is done by providing a U-shaped conductor arrangement with different sections. A central connecting portion with a round cross-section serves as an element of the current transformer for passing through the corresponding opening in the core. Two connection conductors with a rectangular cross section are used to connect the conductor in the form of known per se connectors. The conductor arrangement thus consists of three metal parts with mutually different cross-sections, wherein the two ends of the round conductor are to be fastened to the flattened surfaces of the rectangular connection conductors.

The inductive element used in EP 0 389 678 A1 has a winding conductor as a current conductor and two connection conductors on opposite sides of the winding conductor. The leads are flattened to provide a pad for use as an SMD component and are joined to pads of a printed circuit board by soldering.

From the U.S. 4,785,527 For example, a method of fabricating an inductive chip with metal terminal strips is known. Here, a metallic strip, which is provided with slit-shaped openings, equipped with magnetic or non-magnetic cores. These cores are then wound with a wire. Thereafter, the ends of the wire are connected to portions of the metal strip and the core is provided with a housing. The packaged component is then cut off from the metal strip together with the portions of the metal strip so that the portions form terminals of the component, which are finally bent over.

The US Pat. No. 4,491,818 discloses the preamble of claim 1 and describes a coil having a toroid wound with a wire. The coil is mounted standing on a printed circuit board. Through the opening of the toroidal core, a conductor is passed, the ends of which are soldered to the circuit board. In the area of the opening, the conductor runs parallel to the printed circuit board.

In addition to soft soldering, which is commonly used to make a connection of SMD components, bonding by means of resistance spot welding or brazing is known for attaching a conductor to a lead. However, both methods require a complex process technology and a high energy input for each connection point to be created. As a particular difficulty, the production-accompanying review of the connection points to ensure the quality of the conductor arrangement is to be seen, since in particular the welding in the sense of DIN ISO 9001 is classified as a so-called special process, as is Joining technology, welding technology, DVS publishing house, ISBN 3-87155-786-2, page 328, 2004 , is known. Particularly critical are the effects of oxide layers on the connection partners, the wear of the electrodes and the lack of possibility of meaningful, such as optical or electrical testing of the compound.

The compounds of such a conductor arrangement of three elements with each other at the connection points different cross-sections should allow a long life of, for example, about 10-15 years with great reliability, so that the production of the conductor arrangement must be performed very reliable process. For reasons of electrical conductivity, corresponding busbars or conductor arrangements are predominantly constructed from copper material. But problems arise both in brazing and welding in particular by the heating when creating the connection points, since the heat is transmitted through the conductor to the current transformer and can damage it.

Commonly known for joining two metals is the so-called cold-press welding, which is described for example in the overview of the state and the development tendencies of cold-press welding, J. Ruge, H. Price and K. Thomas, Braunschweig, DVS Report, vol. 139, "Flame Butt Welding and Friction Welding by Related Techniques", page 25, 1991 , From the research report "Investigation of ultrasound-assisted cold-pressure welding for applications in the production of small parts", Institute of welding technology TU Braunschweig, Institute for Joining and Blasting Otto von Guericke, University of Magdeburg, AiF No. 12494 BG / 4 01.06.2000 / 30.09 .2002 and from "Information and application instructions for Tox-connection technology of the company Tox-Pressotechnik GmbH & Co. KG, Weingarten is a clinching known as a kind of riveting of two metallic body.

The object of the invention is to propose an inductive component, in particular for a current detection device and a method for producing such an inductive component, which provides a simple production with a secure connection and the lowest possible load of other components.

This object is achieved by an inductive component having the features of patent claim 1 and by a method for producing an inductive component having the features of patent claim 20. Embodiments and developments of the inventive concept are the subject of dependent claims.

Accordingly, an inductive component is provided with a current conductor with non-rectangular cross-section for conducting a current to be detected, at least one planar connection conductor for supplying or discharging the current to be detected to or from the conductor, wherein the conductor and the connection conductor in the area of a connection portion of the conductor to form a conductor arrangement are connected to each other, and wherein the conductor in the region of the connecting portion has a flattened, in particular rectangular cross-section and a flat surface of the connecting portion of the conductor is connected to a flat surface of the connecting conductor. The device has a magnetic module with an opening through which the conductor is passed.

In addition, the invention comprises a method for producing a conductor arrangement for an inductive component, in particular for use in a current detection device, in which a current conductor with non-rectangular cross-section is connected to a planar connection conductor, wherein the conductor in the cross section in a connecting portion of the conductor ( in particular with rectangular cross-section) is flattened, and the flattened connecting portion of the conductor is connected to the connecting conductor.

In addition, an inductive component can be provided in which the cross section of the current conductor is formed away from the connecting section with an arcuate, in particular round, outer contour, in particular an oval or round cross-sectional shape.

The inductive component can be designed with two connecting sections on the conductor for connecting the conductor to two connecting conductors.

In addition, the compound is formed as a press connection, in particular as a cold press connection.

It is particularly advantageous if the press connection is designed as a clinching connection.

It is also possible to provide an inductive component in which the press connection between the connection section and the connection conductor is formed twice.

Furthermore, the current conductor and the connecting conductor or conductors may be formed as metal parts made of copper or a copper alloy.

The inductive component according to the invention can be, for example, a magnetic module for current detection. The magnetic module can be designed as a current transformer or transformer.

In particular, a current transformer preferably has a toroidal core. The ring core is preferably formed as a ring band core. Advantageously, the ring core is formed of an amorphous or nanocrystalline alloy.

The current conductor may have a deformation, in particular compression, for fixing and / or aligning in an opening of the current transformer with respect to the other cross section.

The contact points can be freed, cleaned and / or plasma-activated in the region of the connection section and / or the connection conductor of metal oxides. Also advantageous is a current detection device, in which the current conductor, the connecting portion and / or the connecting conductor are annealed by means of a heat treatment.

Preferably, the connection is carried out as a press connection by means of a clinching technique. A method is preferably used in which contact points are freed from metal oxides before being combined with a chemical treatment, in particular pickling. The contact points can be cleaned and / or activated on the surface before being connected by means of a plasma treatment. Also advantageous is a method in which the current conductor, its connecting portion and / or the connecting conductor is annealed before joining by means of a heat treatment or are.

The conductor arrangement thus represents a cost-optimized and long-term stable construction of power line rails. In a simple manner, the conductor with the non-rectangular cross section, in particular with a round or nearly round cross section on the one hand and on the other hand at least one connecting conductor with a flat surface, in particular a rectangular cross section with each other, which have a stable and durable connection. In a press connection without the use of heat by, for example, soldering or welding, there is the particular advantage that no heat is transmitted via the conductor to adjacent components of the toroidal core and the like. The second connection between the current conductor and a second connection conductor can, for example before the insertion of the conductor in the opening of the current transformer or toroidal be created so that eventually only one such connection is required.

By flat pressing the ends of a round bar as a current conductor, whereupon the current transformer sits, flat areas are created, which after being superimposed with the flat terminal lugs by a cold press connection, e.g. Durchsatzfügen or clinching are connected permanently and with minimal transmission resistance or are. Of course, the flattening of the conductor does not necessarily take place at the ends, but can also be done in another area adjacent to the toroidal core or current transformer.

In particular, a cold welding in conjunction with a riveted connection requires a high degree of deformation, so that advantageously a soft metal such as copper or a copper alloy is used. By means of a corresponding pretreatment of the connection partners, that is to say of the current conductor and of the connecting conductor or conductors, a cold welding connection can be further improved with regard to the electrical properties, for example minimum contact resistance and gas tightness. The so-called cold pressure welding offers the advantage of a welding process in which a connection is complete, without external thermal energy supplied by pressure alone. The clinching represents a riveting, which advantageously without rivet, that is, without foreign materials manages by the material of one partner involved, for example, the conductor is pressed deep into a forming cavity in the other partner, such as the terminal conductor, wherein forms a mushroom-shaped undercut corresponding to the shape of a press-stamp and a die, so that a positive and non-positive connection is achieved.

There are a variety of advantages through the connection technology and the structure of the conductor arrangement. In addition to good electrical properties, a mechanically very robust connection is created. A simple manufacturing technique allows plant investment of only 30-50% compared to the corresponding welding / brazing technique. A simple and inexpensive maintenance of the production facilities is possible in comparison to the welding / brazing technique. Compared to the welding / brazing technique, when using a cold weld joint, no heating of the metal parts occurs, so that no separate cooling is necessary to protect a plastic coating, for example, a current transformer. Vapors, sparks or chips are avoided. A quality assurance is possible by controlling simple mechanical dimensions, for example the thickness in the formed "rivet". Furthermore, the energy costs per connection point during manufacture are three to five times lower than in the welding / brazing technique. Compared to the spot-weld technique of clinch-clinching, the cost per connection point, taking into account even the investment cost, operating cost and tooling cost, is about 5: 1 more favorable when using clinching.

Since the conductor arrangement serves to transmit an electrical current, heating of the conductor arrangement by the current flow, in particular in the region of the connection points, must also be considered. The electrical resistance of a typical U-shaped busbar is about 100μ ohms. At a current of about 200 A, a power dissipation of 4 W is produced in the unit according to Pv = I ² × R, which results in heating. It should be noted that the connection points do not represent a constriction of the cable cross-section. In the case of a poor connection, the temperature there rises significantly above the level of the remaining connection parts due to the higher voltage drop and accelerates the damage or aging of the contact point. This can lead to an increase in the contact resistance. This is a cumulative process, which may result in further increasing temperatures and eventually failure of the joint. In the case of a welded or in particular a soldered connection, this can lead to partial or complete melting of the connection point due to overheating. Whether soldering or welding bridges are long-term stable, is therefore usually very uncertain. An arc occurring in the final stage of such a failure scenario can result in the complete interruption of the electrical connection. As a requirement for the connection point, therefore, a low-resistance connection with simultaneously high mechanical strength must be required, so that the contact resistance by vibration, vibration or shock during assembly or during subsequent use does not increase significantly.

Advantageously, the current detection device according to the invention or the described manufacturing method provides a low-resistance connection with simultaneously high mechanical strength, which allows a permanent connection even in the case of heating occurring during operation when using a clinching.

Fig. 1

einzelne Fertigungsschritte bei der Fertigung eines erfindungsgemäßen induktiven Bauteils;

Fig. 2

montierte Komponenten eines induktiven Bauelements gemäß einer ersten Ausführungsform;

Fig. 3

montierte Komponenten eines induktiven Bauelements gemäß einer zweiten Ausführungsform;

Fig. 4

einen Querschnitt durch einen Durchsetzfügepunkt; und

Fig. 5

eine beispielhafte für sich bekannte SchaltungsAnordnung, bei welcher derartige Bauelemente eingesetzt werden können.

The invention will be explained in more detail with reference to the embodiments illustrated in the figures of the drawing. It shows:

Fig. 1

individual production steps in the manufacture of an inductive component according to the invention;

Fig. 2

mounted components of an inductive component according to a first embodiment;

Fig. 3

mounted components of an inductive component according to a second embodiment;

Fig. 4

a cross section through a clinching point; and

Fig. 5

an exemplary circuit arrangement known per se, in which such components can be used.

Fig. 1 shows in various manufacturing steps components of a current detection device, which will be described in the following representative and exemplary of inductive components according to the invention. As the uppermost a current conductor 1 is shown, which, as shown in the middle, is passed through an opening 20 of a current transformer 2. The conductor has a non-rectangular, in particular a round cross-section. For example, for anchoring within the opening 20 of the current transformer 2, the cross-section of the conductor 1 in this area may also be slightly deformed, for example slightly flattened or oval instead of circular, to come into clamping engagement with the wall of the opening 20. Instead of a circular conductor 1 but in principle also conductors with other cross-sectional shapes can be used as circular cross-sectional shapes. In principle, for example, cross sections in the form of an octet, square or optionally triangular or cross sections with wavy or serrated outer circumference can be used, which stand out clearly from a flat rectangular shape.

After passing through the current conductor 1 through the opening 20 of the current transformer 2, the end of the current conductor 1 passed through the opening 20 of the current transformer 2 is flattened to form a connecting section 3. In a particularly simple manner, the flattening is done by squeezing, which is particularly easy, especially in a conductor 1 made of copper or a copper alloy. In the illustrated embodiment, the connecting portion 3 of the conductor 1 has a substantially rectangular Cross-section on. In principle, however, other cross-sections which have a flattening on one side, for example also a flattening by material removal, can advantageously be implemented.

Fig. 2 shows an output stage of a preferred conductor arrangement of the conductor 1 with connecting portions 3 at both ends, the current transformer 2, through the opening 20 of the conductor 1 passes between the connecting portions 3, and with two connecting conductors 4, which are elongated, flat pins with rectangular or in Substantially rectangular cross-section are formed. To connect the connecting portions 3 with the connecting conductors 4, the flattened connecting portions 3 are placed with their flat surface on the flat surface of the connecting conductor 4 and connected together. The connection can be made in any manner known per se, for example by soldering or welding. But especially preferred is a cold connection without the supply of heat by means of, for example, cold press welding and / or clinching.

A guided through one of the two terminal conductor 4 and the corresponding connecting portion 3 in the conductor 1 current is passed through the opening 20 of the current transformer 2 and discharged through the second connecting portion 3 and the second terminal conductor 4. The current passed through the current transformer 2 induces in the current transformer 2 a current flow which is conducted via lines 21 of an evaluation circuit for detecting the current flow.

In the embodiment according to Fig. 2 is a conductor arrangement shown, in which the two connecting portions 3 of the conductor 1 were generated from the originally round rod-shaped conductor 1 by pressing. When pressing the thickness of the rod is reduced and creates a flat surface. With the help of a connection technique based on the By clinching, the ends of the round bar and the rectangular terminal lugs formed by the terminal conductors 4 are connected to each other. The strong deformation in the region of the connection points of the clinching results in button-shaped rivets 5, so that by means of a cold welding a mechanically stable connection and a good electrical contact for a secure flow of current are generated. Figure 4 illustrates a cross-section through an exemplary, by clinching produced connection of a connecting portion 3 and a connecting conductor 4. By the appropriate selection of a stamp the pressed from the connecting portion 3 in the terminal conductor 4 material assumes a mushroom-shaped cross-section and forms a Hintergreifung to form a mechanical high stability in the manner of a rivet. Shown is the case of an 8 mm wide riveting by means of clinching, but also other dimensions can be selected according to the needs.

At a clinching point of the exemplary size of 8 mm between two copper parts with the thicknesses of 2.4 mm each, the first tests showed a shear strength of more than 1600 N and a head tensile strength of more than 1500 N.

Fig. 2 shows an embodiment, each with a clinching point 5 for connecting the corresponding connecting portion 3 with the adjacent terminal conductor 4th Fig. 3 shows a further embodiment of a conductor arrangement with also a current conductor 1, the flattened connecting portions 3 are each connected to a terminal conductor 4, wherein for the compounds in each case two clinching points are used. This creates a twist protection of the conductor 1 relative to the two connecting conductors. It is also sketched that the current conductor 1 does not necessarily have to lead straight from one connecting section 3 to the other connecting section 3, but can also have a bend.

Figure 5 shows an exemplary circuit arrangement of a current detection device 0 for detecting a current flow through three conductors L1, L2, L3. In the usual way, a corresponding cable additionally has a neutral conductor N. The three conductors L1, L2, L3 are interrupted and each end in a plug contact 6 for insertion of a contact pin in the form of the connecting conductor 4. Each of the conductors L1, L2, L3 are thus associated with two female plug-in contact elements 6, in which the two connecting conductors 4 of the conductor arrangement according to, for example Fig. 2 or Fig. 3 be plugged in. The current conductor 1 which connects the two connecting conductors 4 via the connecting sections 3 leads through the corresponding opening of a current transformer 2, which, for example, as in FIG Fig. 2 or Fig. 3 can be trained.

For example, three current transformers 2, each with a conductor arrangement made in this way, are arranged and fastened on a circuit board with electronics for evaluation or current detection. Usually, the electronics are accommodated in a housing from which correspondingly six such connecting conductors 4 protrude as contact pins for insertion into corresponding plug-in contact sockets 6 and a further connecting conductor as a contact pin for a connection to the neutral conductor N. Typically, such electronics also have one or more output devices for outputting the detected amount of current. By way of example, the output device is a display device D. The display device D or another external interface outputs the quantities of current detected by means of signal processing and optionally analog-to-digital converters in the electronics.

In the illustrated circuit diagram of an electronic electricity meter as a current detection device 0 is thus with three push-through current transformers from the three currents to be measured By means of a 1: N transformation and via load resistances in each case generates an individual voltage signal for a AuswerteElektronik and supplied to this. Thereafter, the display of the calculated energy by means of an output device.

Thus, a current conductor system is preferably provided, which serves for the measurement of electrical currents and is formed in particular of three metal parts and a current detection system. The current conductor system consists of a middle part as the current conductor 1, which has a preferably round cross-section and in which after plugging the current transformer 2 as a current detection system at least one, in particular both of its ends as a connecting portion 3 are flattened. In addition, the current conductor system consists of two further parts in the manner of the connecting conductor 4 with a rectangular cross section for the formation of terminal lugs or contact pins for a plug connection.

The connection of the three parts takes place in particular as a cold press connection for forming a mechanically and electrically good connection. A cold press connection is preferably made twice on each side, in order to achieve an additional safeguard against twisting while increasing the connection cross section. The current detection system preferably consists of a transformer-type current transformer. A current transformer is preferably a toroidal core, in particular a toroidal core formed as a toroidal core made of an amorphous or nanocrystalline alloy. The round metal rod forming the current conductor 1 preferably has a deformation, in particular a slight compression, in the middle region or in the region which is passed through the opening 20 of the current transformer 2, as a result of which the current transformer 2 is plugged into the current conductor 1 in a desired manner Position fixed and thus secured.

To improve the connection, the contact points are advantageously removed before joining, in particular before the clinching, with a chemical treatment such as pickling of metal oxides. The contact points are cleaned or activated before the clinching or other connection, for example, with a treatment in a plasma on the surface. It is also advantageous to soft anneal the metal parts before the clinching by a heat treatment.

Although current detection devices are referred to in the above embodiments, it should be understood that any of the inductive components, such as chokes, transformers and other types of magnetic modules, may be designed and manufactured in accordance with the present invention.

Claims (25)

1. Inductive component (0) with a current conductor (1) for conducting a current, with at least one flat connecting conductor (4) for supplying or discharging a current to or from the current conductor (1), wherein the current conductor (1) and the connecting conductor (4), in the area of the connection section (3) of the current conductor (1), are connected to one another with formation of a conductor arrangement, wherein the inductive component (0) comprises a magnetic module with an opening (20) through which the current conductor (1) is led, and the current conductor (1), to the side of the connection section (3), is formed as a straight or curved rod with non-rectangular cross section,
   characterized in that
   the current conductor (1) has a flattened cross section in the area of the connection section (3), a flat surface of the connection section (3) of the current conductor (1) is connected to a flat surface of the connecting conductor (4), and the connection is formed as a press fit connection.
2. Inductive component according to Claim 1, in which the cross section of the current conductor (1) to the side of the connection section (3) is formed with a curved outer contour.
3. Inductive component according to Claim 2, in which the cross section of the current conductor (1) to the side of the connection section (3) is formed with rounded outer contour.
4. Inductive component according to Claim 2, in which the cross section of the current conductor (1) to the side of the connection section (3) is formed with oval outer contour.
5. Inductive component according to a previous claim, with two connection sections (3) on the current conductor (1) for connecting the current conductor (1) to two connecting conductors (4).
6. Inductive component according to a previous claim, wherein the connection is formed as a cold press fit connection.
7. Inductive component according to one of Claims 1 to 5, wherein the press fit connection is formed as a press joint connection (5).
8. Inductive component according to one of Claims 1 to 5, wherein the press fit connection between the connection section (3) and the connecting conductor (4) is formed in duplicate.
9. Inductive component according to a previous claim, wherein the current conductor (1) and the connecting conductor(s) (4) are formed as metal parts made of copper or of a copper alloy.
10. Inductive component according to a previous claim, in which the inductive component comprises a magnetic module with an opening (20), wherein the current conductor (1) is led through the opening (20).
11. Inductive component according to a previous claim, wherein the magnetic module is formed as a transformer.
12. Inductive component according to Claim 11, wherein the transformer (2) comprises an annular core.
13. Inductive component according to Claim 12, wherein the annular core is formed as an annular strip core.
14. Inductive component according to Claim 12 or 13, wherein the annular core is formed from an amorphous or nanocrystalline alloy.
15. Inductive component according to a previous claim, wherein the current conductor (1) has a deformation relative to the rest of the cross section, for the attachment and/or alignment in an opening (20) of the current transformer (2).
16. Inductive component according to Claim 15, wherein the deformation is a pressing.
17. Inductive component according to a previous claim, wherein contact positions in the area of the connection section (3) and/or of the connecting conductor (4) are freed of metal oxides, cleaned and/or plasma activated.
18. Inductive component according to a previous claim, wherein the current conductor (1), the connection section (3) and/or the connecting conductor (4) are soft annealed by means of a heat treatment.
19. Inductive component according to a previous claim, in which the current conductor (1) has a rectangular cross section in its flattened section.
20. Method for producing an inductive component (0) according to one of Claims 1 to 19, in which a current conductor (1) formed as straight or curved rod with non-rectangular cross section to the side of the connection section (3) and led through the opening (20) of a current module is connected to a flat connecting conductor (4), characterized in that, in the case of the current conductor (1), the cross section is flattened in a connection section (3) of the current conductor (1), the flattened connection section (3) of the current conductor (1) is connected to the connecting conductor (4), and the connection is formed as a press fit connection.
21. Method according to Claim 21, in which the connection is implemented as a press fit connection using a press joining technique.
22. Method according to Claim 20 or 21, in which contact positions are freed of metal oxides by a chemical treatment before the connection.
23. Method according to Claim 22, in which contact positions are freed of metal oxides by acid cleaning before the connection.
24. Method according to one of Claims 20 to 23, in which contact positions are cleansed and/or activated by means of a plasma treatment on the surface before the connection.
25. Method according to one of Claims 20 to 24, in which the current conductor (1), its connection section (3) and/or the connecting conductor (4) is/are soft annealed by means of a heat treatment before the connection.

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