Sleeve and method for producing sleeve

Abstract

A bushing (100) comprises a plurality of electrically conductive elements (1, 2a... 2c, 3, 4, 6) and at least one ultrasonic welded joint (10). The at least one ultrasonic weld joint is formed between the one conductive element and the other conductive element and mechanically and electrically connects the one conductive element and the other conductive element to each other.

Description

Technical Field

[0001] The present disclosure relates to a casing and a method for producing a casing. Background Art

[0002] Document EP 3 869 525 A1 relates to a bushing (1) comprising an electrical conductor having a terminal at a first end of the bushing. The outer field grading layer is electrically connected to the flange by means of an electrically conductive connection.

[0003] Document EP 3 148 027 A1 relates to a high voltage cable fitting comprising a rigid conical insulator arranged coaxially around an axis, an electrically insulating elastomeric stress relief cone mating with the rigid conical insulator via a conical interface and axially aligned current paths. The central tube is electrically connected to the innermost field grading layer by means of a short high voltage conductor. Summary of the invention

[0004] There is a need for an improved sleeve, such as a sleeve having a reliable internal connector. In addition, there is a need for an improved method for producing such a sleeve.

[0005] Embodiments of the present disclosure relate to an improved casing and an improved method for producing casing.

[0006] First, the bushing is described in detail.

[0007] According to an embodiment, the sleeve includes a plurality of conductive elements and at least one ultrasonic weld joint, wherein the at least one ultrasonic weld joint is formed between one conductive element and another conductive element and mechanically and electrically connects the one conductive element and another conductive element to each other.

[0008] An ultrasonic welded joint is understood herein to be a mechanically sound and electrically conductive joint formed by fusing two metals at the joining surfaces, the fusing being formed at least in part by means of vibrations within the ultrasonic bandwidth applied from an external energy source.

[0009] The bushing described herein is, for example, a high voltage bushing. Therefore, it is configured to carry a current at high potential from an active part of a first high voltage component (such as a transformer, a generator or a circuit breaker) through a barrier (such as a grounded housing of the first component) to a second high voltage component (such as a high voltage overhead line or a high voltage cable terminal). Such high voltage bushings are used in switchgear facilities (such as gas insulated switchgear GTS or air insulated switchgear AIS), power or distribution transformers, or high voltage rotating machines (such as generators). High voltage bushing examples are configured for voltages ranging from a few kV to up to hundreds of kV and even exceeding 1000 kV.

[0010] Internal joints of bushings, especially high voltage bushings, are known to cause bushing failures. Especially in high voltage bushings, ensuring low electrical impedance of the joints is critical to prevent high current transients from damaging the joints. Currently, there are a variety of methods for forming joints in bushings, including brazing and mechanical fasteners.

[0011] Brazing involves heating conductive components and using toxic fluxes and metals. It cannot be used effectively on any connections other than Cu to Cu joints.

[0012] Mechanical fasteners cannot be used on foils, for example due to the large size of the fasteners relative to the foil thickness, and if used in electrically stressed areas, protrusions of the fasteners can cause partial discharges.

[0013] As suggested herein, the use of ultrasonic welding for internal connections avoids the use of an intermediate substance between the conductive elements. This reduces the risk of electrical failure. The electrical integrity of ultrasonically welded connections exceeds that of soldering because no heating of the conductive elements is required when ultrasonic welding is used, and therefore, ultrasonic welding can be performed on conductive elements that are, for example, in close proximity to plastics.

[0014] Ultrasonic welding involves high frequency vibrations being transmitted into the conductive elements to be welded. The resulting surface friction causes the material of one of the conductive elements to diffuse into the other conductive element, thus forming a weld joint between these elements. An important advantage of ultrasonic welding is that the temperature of the conductive elements is well below their melting temperature. Ultrasonic welding can therefore be applied in particular to foils, which then do not melt or burn during the ultrasonic welding process, even when they are welded to elements with a large thermal mass.

[0015] The sleeves detailed herein may include several ultrasonic welded joints. All features disclosed herein for one ultrasonic welded joint are also disclosed for all other ultrasonic welded joints.

[0016] The ultrasonic weld joint is an internal joint of the sleeve. For example, it is not visible from the outside of the sleeve and / or is not accessible from the outside of the sleeve.

[0017] Ultrasonic welded joints may also be referred to as ultrasonic welded connections or ultrasonic welded joints or ultrasonic welded joints / connections / joints. Ultrasonic welded joints are arranged directly between the conductive elements to which they are firmly connected. Thus, for example, there is no additional connecting material between the two conductive elements. The conductive elements may each be formed of a metal or may include a metal.

[0018] When studying a joint between two elements, a technician can determine which joining method was used. In particular, a technician can see whether two conductive elements are connected at least in part via ultrasonic welding. The main identifying characteristic of an ultrasonically bonded joint is the lack of intermediate or foreign bonding material, but rather the presence of an interface layer at the joint that includes an alloy of the two metals that are joined together. Further, there may be features on the opposing outer surfaces of the metals being joined that should indicate the application of pressure using a tool that is in direct contact with the metal surfaces. These features take the form of regular or irregular indentation formations of varying depths into the base metal, for example.

[0019] According to a further embodiment, the bushing is a condenser bushing. It comprises an inner conductor for transmitting electric current and at least two field grading layers formed of an electrically conductive material and arranged around the inner conductor. An electrically isolating material is arranged between the at least two field grading layers and electrically isolates them from each other.

[0020] The inner conductor is for example made of metal or comprises metal, such as Cu or Al. The field grading layers are made of conductive material. For example, the field grading layers comprise metal or are made of metal (e.g. made of metal foil). They may comprise Al or consist of Al. Alternatively, the field grading layers may also comprise conductive ink impregnated into paper or may be made of conductive ink. The field grading layers are separated and electrically isolated from each other via an electrically isolating material and thus constitute a capacitor. The field grading layer closest to the inner conductor may be electrically connected to the inner conductor. The field grading layer farthest from the inner conductor may be electrically connected to ground.

[0021] The inner conductor may be an elongated body with a main extension axis, such as a rod. The field grading layers may radially surround the inner conductor. For example, they form concentric cylindrical housings around the inner conductor. The electrically isolating material is then radially arranged between each two field grading layers. The electrically isolating material may also be arranged between the inner conductor and the field grading layer closest to the inner conductor.

[0022] The electrical isolation material may comprise plastic and / or paper and / or oil and / or epoxy resin. For example, the electrical isolation material comprises a woven or non-woven fabric. The fabric may be embedded in the epoxy resin. For example, a stack of several layers made of isolation material is formed between every two adjacent field grading layers. These stacked layers may be formed by an isolation tape wound around the inner conductor.

[0023] According to a further embodiment, the inner conductor and / or the at least one field grading layer are mechanically and electrically connected to the other conducting element by means of at least one ultrasonic weld joint.

[0024] According to a further embodiment, the further conductive element is a metal braid, such as a copper (Cu) braid.The metal braid may be a flat braid or a round braid.

[0025] According to a further embodiment, the section of the metal braid adjoining the ultrasonic welded joint is a solidified section in which the wires of the braid are connected to each other in a material-locked manner. Thus, the wires in this area cannot be separated from each other without causing damage. For example, the wires are welded to each other, for example by means of resistance welding, and are thus fused together in this section.

[0026] According to a further embodiment, the inner conductor is electrically connected to the inner field grading layer of the bushing via a first connecting element (e.g. a first metal braid). Additionally or alternatively, the outer field grading layer of the bushing is electrically connected to the housing element of the bushing via a second connecting element (e.g. a second metal braid). Both the first metal braid and the second metal braid may be flat metal braids, such as Cu braids. Instead of metal braids, foil strips may be used.

[0027] The inner field grading layer is herein the field grading layer closest to the inner conductor, e.g. the radially innermost field grading layer. The outer field grading layer is herein the field grading layer farthest from the inner conductor, e.g. the radially outermost field grading layer. The housing element is, for example, a flange of a bushing. The flange is, for example, configured to be connected to a housing of a transformer. The housing element may radially surround the inner conductor and each of the field grading layers. For example, the housing element is formed of a conductive material, such as a metal.

[0028] According to a further embodiment, the inner conductor is mechanically and electrically connected to the first connecting element (eg to the first end thereof) by means of at least one ultrasonic weld joint.

[0029] According to a further embodiment, the inner field grading layer is mechanically and electrically connected to the first connecting element (eg to the second end thereof) by means of at least one ultrasonic weld joint.

[0030] According to a further embodiment, the outer field grading layer is mechanically and electrically connected to the second connecting element (eg to a first end thereof) by means of at least one ultrasonic weld joint.

[0031] According to a further embodiment, the housing element is mechanically and electrically connected to the second connecting element (eg to the second end thereof) by means of at least one ultrasonic weld joint.

[0032] According to a further embodiment, the field grading layer (e.g. the external field grading layer or a field grading layer adjacent to the external field grading layer) is electrically connected to the voltage tap via a third connecting element. The third connecting element may comprise a (circular) metal braid and / or a metal foil. The metal braid and the metal foil of the third connecting element may be formed of Cu. The third connecting element may be mechanically and electrically connected to the field grading layer by means of at least one ultrasonic welded joint. Furthermore, the third connecting element may be mechanically and electrically connected to the voltage tap by means of at least one ultrasonic welded joint.

[0033] For example, the metal braid of the third connecting element is mechanically and electrically connected to the voltage tap by means of an ultrasonic welded connection. The metal braid of the third connecting element may be mechanically and electrically connected to the metal foil of the third connecting element by means of soldering. The metal foil of the third connecting element may be mechanically and electrically connected to the field grading layer by means of an ultrasonic welded joint.

[0034] According to a further embodiment, at least one ultrasonic weld joint is formed between a conductive element made of Cu and / or Al and another conductive element made of Cu, and mechanically and electrically connects these conductive elements. For example, an ultrasonic weld joint in a sleeve may be formed between one or more of:

[0035] -Solid Al and Cu foils,

[0036] - Solid Cu and Cu foil,

[0037] - Solid Cu and Al foils,

[0038] -Al foil and Al foil,

[0039] -Cu foil and Cu foil,

[0040] -Solid Al and Cu braid,

[0041] - Solid Cu and Cu braid,

[0042] -Cu braid and Al foil,

[0043] -Cu braid and Cu foil,

[0044] -Cu foil and Al foil.

[0045] Alternatively, at least one of the conducting elements connected to another conducting element by means of an ultrasonic weld joint comprises or consists of brass.

[0046] According to a further embodiment, at least one of the conducting elements which is firmly connected to another conducting element by means of at least one ultrasonic weld joint is a metal foil.A metal foil is understood herein as a foil having a thickness of, for example, at most 1 mm or at most 100 μm.

[0047] According to a further embodiment, at least one of the conductive elements that is mechanically and electrically connected to another conductive element by means of at least one ultrasonic weld joint comprises a structure embossed into the conductive element. The structure may be a structural embossment of a welding tool (e.g., anvil and / or sonotrode / horn) of a welding device for ultrasonic welding. For example, the structure is embossed into the side of the conductive element facing away from the ultrasonic weld joint. In a top view of the conductive element, the structure may overlap with the ultrasonic weld joint.

[0048] For example, the structure comprises a plurality of regularly or irregularly arranged recesses and / or protrusions on the outer surface of the conductive element (i.e., the surface facing away from the ultrasonic weld joint). These structures are, for example, perpendicular to the plane of the weld joint and appear on the surface of the conductive element that is in direct contact with the tool of the ultrasonic device.

[0049] The depth and / or height of the structures entering / exiting the outer surface depends on the thickness and hardness of the conductive element and the size of the solder joint. The appearance of the structures can be a geometric pattern of alternating protrusions and / or recesses forming lines, squares, triangles, etc. Moreover, the appearance of the structures can be a random and irregular pattern of protrusions and / or recesses of varying sizes, shapes and depths / heights.

[0050] The depth of each recess / protrusion and / or its extension parallel to the outer surface is for example at least 1 μm, or at least 10 μm, or at least 100 μm. Additionally or alternatively, the depth and / or lateral extension of each recess may be at most 1 mm or at most 100 μm.

[0051] According to a further embodiment, the structure is a knurled structure.

[0052] It has been shown that, at least in some applications, an ultrasonic weld joint formed using a structured welding tool and in which the structure is impressed into at least one of the conductive elements has a lower impedance than an ultrasonic weld joint formed using a smooth welding tool. For example, if one of the conductive elements is a metal foil, such a structure can be formed in the metal foil. In general, ultrasonic weld joints have been shown to have a lower impedance than other joints, such as soldered joints.

[0053] Next, a method for producing a sleeve is described in detail. The method can be used to produce the sleeve as described in detail herein. Therefore, all features disclosed in conjunction with the sleeve are also disclosed for the method, and vice versa.

[0054] According to an embodiment, a method for producing a bushing comprises providing a conductive element, i.e. two or more conductive elements. The method further comprises the step of ultrasonically welding one of the conductive elements to another of the conductive elements. Thus, an ultrasonic weld joint is formed between the conductive element and the other conductive element, which ultrasonic weld joint mechanically and electrically connects the conductive element to the other conductive element.

[0055] Ultrasonic welding can be accomplished with the aid of an ultrasonic welding device. This can include at least one welding tool, such as an ultrasonic horn or sonotrode. Additionally, the ultrasonic welding device can include an anvil. Moreover, other methods or devices can be used to stabilize the weld joint and provide a reaction pressure to overcome the force of the welding tool during the welding process.

[0056] To form an ultrasonic weld joint, a conductive element and another conductive element may be pressed against each other with the aid of a welding tool. Ultrasonic acoustic vibrations are then induced into the two conductive elements, for example via the welding tool. As a result, the material of one conductive element diffuses into the material of the other conductive element, so that a weld joint is formed.

[0057] The conductive element and the further conductive element may be sandwiched between the ultrasonic horn and the anvil and may be pressed together between the two elements. Alternatively, if the conductive element is mechanically stable, a separate anvil may be omitted and the further conductive element may be sandwiched between the mechanically stable conductive element and the ultrasonic horn.

[0058] According to a further embodiment, the further conductive element is a metal braid, for example a metal braid of Cu.

[0059] According to a further embodiment, before ultrasonic welding, the section of the metal braid to be ultrasonically welded is solidified by connecting the wires of the metal braid in this section in a material-locking manner. Connecting these wires can be done by welding (e.g. resistance welding). The wires are thereby fused together.

[0060] With this additional step, individual wires can be prevented from protruding from the section of the metal braid to be ultrasonically welded. Such protruding wires cannot be welded during the ultrasonic welding process and this may indeed increase the impedance of the ultrasonic welded joint.

[0061] According to a further embodiment, a welding tool is used to ultrasonically weld a conductive element to another conductive element, the welding tool comprising a surface having a structure (ie, a structured surface). For example, the ultrasonic horn and / or the anvil comprises such a structured surface.

[0062] According to a further embodiment, for ultrasonically welding the conductive element to the further conductive element, the conductive element and the further conductive element are pressed together with the aid of a welding tool such that a structure of a surface of the welding tool is impressed into at least one of the conductive element and the further conductive element.

[0063] So far, several features have been disclosed in connection with the production of one ultrasonic welded joint. If applicable, these features are also disclosed for the production of all other ultrasonic welded joints of the sleeve. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Hereinafter, the casing and the method for producing the casing will be explained in more detail with reference to the accompanying drawings based on exemplary embodiments. The accompanying drawings are included to provide further understanding. In the accompanying drawings, elements of the same structure and / or function may be referenced by the same reference numerals. It will be understood that the embodiments shown in the accompanying drawings are pictorial representations and are not necessarily drawn to scale. As long as elements or components correspond to each other in terms of their functions in different drawings, their description will not be repeated for each of the following drawings. For clarity, elements may not appear in all figures with corresponding reference symbols.

[0065] Figure 1 An exemplary embodiment of a sleeve is shown in cross-section.

[0066] Figures 2 to 7 The enlarged image shows Figure 1 Different parts of the casing,

[0067] Figure 8 A flow chart showing an exemplary embodiment of a method for producing casing,

[0068] Fig. 9 and Fig.10 Different positions in an exemplary embodiment of a method for producing a casing are shown. DETAILED DESCRIPTION

[0069] Figure 1 An exemplary embodiment of a bushing is shown in a cross-sectional view. The bushing 100 is a high voltage capacitor bushing comprising a plurality of field grading layers 2a, 2b, 2c radially surrounding an inner conductor 1. The inner conductor 1 is, for example, a solid Cu or Al rod. The field grading layers 2a, 2b, 2c are, for example, Al foils which are wound around the inner conductor 1 and form a coaxially arranged cylindrical shell. An electrically isolating material 5 is arranged between each pair of adjacent field grading layers 2a, 2b, 2c and electrically isolates the adjacent field grading layers 2a, 2b, 2c from each other.

[0070] The electrically isolating material 5 may be formed, for example, by an electrically isolating tape wound around the inner conductor 1. One or several turns of the isolating tape may be arranged between each pair of adjacent field grading layers 2a, 2b, 2c. The electrically isolating tape may comprise a plastic fabric.

[0071] The bushing 100 further comprises a housing element 3 in the form of a flange. For example, the flange 3 may be grounded and may be configured to be connected to the housing of a transformer. Thus, during operation, a voltage difference occurs between the inner conductor 1 and the flange 3. The field grading layers 2a, 2b, 2c are configured to make the electric field between the inner conductor 1 and the housing of the bushing 100 uniform.

[0072] The inner conductor 1 is electrically connected to the inner field grading layer 2a via a first connecting element 4. The outer field grading layer 2c is electrically connected to the flange 3 via a second connecting element 4. Furthermore, the middle field grading layer 2b is electrically connected to a voltage tap 7 via third connecting elements 4,6.

[0073] Figure 2 A detailed view of the connection between the inner conductor 1 and the first connecting element 4 is shown in a side view. The first connecting element 4 is, for example, a flat Cu braid. An ultrasonic weld joint 10 is formed between the inner conductor 1 and the Cu braid 4, which connects the inner conductor 1 to the Cu braid 4 mechanically and electrically.

[0074] Figure 3 A detailed view of the connection between the first connecting element 4 (Cu braid 4) and the inner field grading layer 2a is shown in a side view. Here again, an ultrasonic weld joint 10 is formed between the field grading layer 2a and the Cu braid 4, which mechanically and electrically connects the field grading layer 2a and the Cu braid 4 to each other.

[0075] Figure 4 Shown with Figure 3 The same elements, but now in a top view onto the field grading layer 2a. The ultrasonic weld joint 10 is indicated by the dotted area, but is actually hidden behind the field grading layer 2a. In the area of ​​the ultrasonic weld joint 10 and at the side facing away from the ultrasonic weld joint 10, the field grading layer 2a comprises a knurled structure 11 embossed into the field grading layer 2a. This structure 11 is a trace of the structure of the welding tool used to press the field grading layer 2a and the Cu braid 4 together during ultrasonic welding.

[0076] Figure 5 Shown with Figure 4 The same elements, but now in a top view onto the Cu braid 4, so that the ultrasonic weld joint 10 is hidden behind the Cu braid 4. Figure 5 It can be seen in FIG. 4 that some of the wires 40 of the Cu braid 4 protrude from the section of the Cu braid 4 ultrasonically welded to the field grading layer 2a. These wires 40 are not ultrasonically welded to the field grading layer 2a, which proves to negatively impair the impedance of the ultrasonic welded joint 10.

[0077] In order to avoid such protruding wires 40 , the sections of the Cu braid 4 to be ultrasonically welded may be cured beforehand (eg, by resistance welding) so that the wires 40 fuse together. Figure 6 Such a solidified section is shown in , where the individual wires 40 are no longer present in the section of the Cu braid 4 ultrasonically welded to the field grading layer 2a.

[0078] Figure 7 A detailed view of the connection of the third connecting element 4, 6 to the middle field grading layer 2b is shown. In this case, the third connecting element 4, 6 comprises a circular Cu braid 4 and a Cu foil 6. The Cu braid 4 is for example soldered to the Cu foil 6. The Cu foil 6 is mechanically and electrically connected to the middle field grading layer 2b by means of an ultrasonic weld joint 10. The Cu foil 6 comprises a knurled structure 11 embossed in the region of the ultrasonic weld joint 10 by a welding tool.

[0079] Figure 8 A flow chart of an exemplary embodiment of a method for producing a bushing is shown. In step S1, conductive elements, such as an inner conductor and a metal foil for forming a field grading layer, are provided. In step S2, one of the conductive elements is ultrasonically welded to another of the conductive elements.

[0080] Fig. 9 1 shows a position in an exemplary embodiment of a method for producing a bushing. In the figure, an elongated inner conductor 1 is provided, which inner conductor is, for example, a Cu rod. The inner conductor 1 is radially surrounded by an electrically insulating material 5. For example, the inner conductor 1 is clamped in a winding machine arrangement, wherein the electrically insulating tape 5 is wound around the inner conductor 1 (see also Fig.10 and Figure 11).

[0081] The winder arrangement comprises an ultrasonic welding device having welding tools 20, 21. The welding tool 20 is an ultrasonic horn or sonotrode and the welding tool 21 is an anvil. The surface of the ultrasonic horn 20 and / or the anvil 21 may comprise structures which are impressed into the elements which are ultrasonically welded together.

[0082] Fig.10 The location of the method is shown. The inner conductor 1 is shown in a cross-sectional view, wherein the main extension axis of the inner conductor 1 is perpendicular to the plane of the paper.

[0083] exist Fig.10 The end of the Cu braid 4 is ultrasonically welded to a portion of the inner conductor 1. The other end of the Cu braid 4 is ultrasonically welded to an Al foil 2a which will later be wound around the inner conductor 1 to form the inner field grading layer of the bushing. Fig. 9 The ultrasonic welding apparatus shown in FIG. 1 forms an ultrasonic weld joint 10 between the Cu braid 4 and the inner conductor 1 or the Al foil 2 a.

[0084] The embodiments shown in the accompanying drawings as stated represent exemplary embodiments of the improved casing and the improved method for producing the casing; therefore, they do not constitute a complete list of all embodiments according to the improved casing and method. The actual casing and method may differ from the embodiments shown in, for example, arrangement, apparatus and materials.

[0085] Reference numerals

[0086] 1 Inner conductor

[0087] 2a..2c Field Grading Layer / Metal Foil

[0088] 3 Flange

[0089] 4 Cu Braid

[0090] 5 Electrical isolation materials

[0091] 6 Cu foil

[0092] 7 Voltage taps

[0093] 10 Ultrasonic welding joints

[0094] 11 Imprinted structure

[0095] 20 Ultrasonic welding head / ultrasonic sonotrode

[0096] 21 Anvil

[0097] 22 Rollers

[0098] 40 lines

[0099] 100 Casing

[0100] S1, S2 method steps

Claims

1. A sleeve (100), comprising: - a plurality of conductive elements (1, 2a..2c, 3, 4, 6), - at least one ultrasonic welded joint (10) formed between one conductive element (1, 2a..2c, 3) and another conductive element (4, 6) and mechanically and electrically connecting the one conductive element to the other conductive element, wherein - The further conductive element (4) is a metal braid.

2. The sleeve (100) according to claim 1, wherein: The bushing (100) is a high-voltage capacitor bushing, and the high-voltage capacitor bushing has: - an inner conductor (1) for transmitting electric current, - at least two field grading layers (2a..2c) formed of an electrically conductive material and arranged around said inner conductor (1), - an electrically isolating material (5) arranged between the at least two field grading layers (2a..2c) and electrically isolating the at least two field grading layers from each other, wherein The inner conductor (1) and / or at least one field grading layer (2a..2c) is mechanically and electrically connected to another conducting element (4) by means of at least one ultrasonic welded joint (10).

3. The sleeve (100) according to claim 1 or 2, wherein: The section of the metal braid (4) adjoining the ultrasonic weld joint (10) is a solidified section in which the threads (40) of the metal braid (4) are connected to one another in a material-locking manner.

4. The bushing (100) according to claim 2 or claim 3 when dependent on claim 2, wherein: - the inner conductor (1) is electrically connected to the inner field grading layer (2a) of the bushing (100) via a first metal braid (4), and the outer field grading layer (2c) of the bushing (100) is electrically connected to the housing element (3) of the bushing (100) via a second metal braid (4), - the inner conductor (1) is mechanically and electrically connected to the first metal braid (4) by means of at least one ultrasonic welded joint (10), - the inner field grading layer (2a) is mechanically and electrically connected to the first metal braid (4) by means of at least one ultrasonic welded joint (10), - the external field grading layer (2c) is mechanically and electrically connected to the second metal braid (4) by means of at least one ultrasonic welded joint (10), The housing element (3) is mechanically and electrically connected to the second metal braid (4) by means of at least one ultrasonic welded joint (10).

5. The bushing (100) according to any one of the preceding claims, wherein - At least one ultrasonic welded joint (10) is formed between a conductive element (1, 2a..2c, 3) made of Cu or Al and another conductive element (4, 6) made of Cu, and mechanically and electrically connects the conductive element made of Cu or Al to the other conductive element made of Cu.

6. The bushing (100) according to any one of the preceding claims, wherein - at least one of the conducting elements (1, 2a..2c, 3) which is mechanically and electrically connected to another conducting element (4, 6) by means of at least one ultrasonic welded joint (10) is a metal foil.

7. The bushing (100) according to any one of the preceding claims, wherein - at least one of the conducting elements (1, 2a..2c, 3) which is mechanically and electrically connected to another conducting element (4, 6) by means of at least one ultrasonic weld joint (10) comprises a structure (11) embossed into the conducting element.

8. The sleeve (100) according to claim 7, wherein: - The structure (11) is a knurled structure.

9. A method for producing a casing (100), comprising: - providing conductive elements (1, 2a..2c, 3, 4, 6), - ultrasonically welding one of the conductive elements (1, 2a..2c, 3) to another of the conductive elements (4, 6), wherein - The further conductive element (4) is a metal braid.

10. The method according to claim 9, wherein: Prior to the ultrasonic welding, the section of the metal braid (4) to be ultrasonically welded is solidified by connecting the threads (40) of the metal braid (4) in this section in a material-locking manner.

11. The method according to any one of claims 9 or 10, wherein: - for ultrasonically welding the conductive element (1, 2a..2c, 3) to the further conductive element (4, 6), - using a welding tool (20, 21) comprising a surface having a structure, - Pressing the conductive element (1, 2a..2c, 3) and the further conductive element (4, 6) together with the aid of the welding tool (20, 21) so that the structure of the surface is impressed into at least one of the conductive element (1, 2a..2c, 3) and the further conductive element (4, 6).

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