COMPOSITE ARRANGEMENT WITH AT LEAST ONE EXPANSION BAND AND METHOD FOR PRODUCING THE COMPOSITE ARRANGEMENT

Description

[0001] The invention relates to a composite assembly comprising at least one expansion band comprising a number of metal bands. Furthermore, the invention relates to a method for producing such a composite assembly.

[0002] A method for welding metallic foils is known from DE 10 2020 120 263 B3. The method comprises the following steps: forming a parallel joint with several metallic foils to be joined by arranging the foils so that they lie against one another over a wide area and the end faces of the stacked foils form one end face of the parallel joint; welding the metallic foils by directing a laser beam onto the end face of the parallel joint of the foils, thus forming a weld seam connecting the foils.

[0003] Furthermore, DE 10 2014 223 352 A1 describes a connecting arrangement. The connecting arrangement comprises a semiconductor, a substrate, and a metal strip. The semiconductor has an electrical connection, which is ultrasonically welded to the substrate by means of the metal strip, wherein the metal strip comprises two metal layers made of different metals or metal alloys. The thickness of the metal layer of the metal strip connected to the connection is half the thickness of the further metal layer of the metal layers connected to the metal layer.

[0004] The patent application DE 10 2009 000 262 A1 discloses a thermal joining method for producing a material-to-material connection between at least two surfaces of one or more workpieces by means of at least one joining seam, in which at least one additional material is used, wherein at least one of the additional materials is already applied to at least one workpiece before joining.

[0005] The patent application DE 10 2005 001 606 A1 discloses a method for joining at least a first sheet and a second sheet by means of laser welding, which are at least partially layered on top of one another so that they form an overlapping region, wherein the sheets are welded together along a pendulum line in the overlapping region after being layered on top of one another.

[0006] The translation of the European patent specification DE 603 ​​12 323 T2 discloses a method for laser-arc hybrid welding of a plurality of metal pieces to be welded using at least one laser beam and at least one arc, wherein the metal pieces are layered on top of one another in a multi-thickness arrangement and wherein the laser beam and the arc edge-weld the multi-thickness arrangement.

[0007] DE 10 2022 004 752 A1 discloses a component arrangement for electrical contacting with at least one expansion band and a component, wherein the expansion band comprises a number of metal bands arranged one above the other and press-welded at their ends. According to the invention, the press-welded end of the expansion band has a bevel and is arranged in a lap joint on the component, and the press-welded end of the expansion band is laser-welded to the component by means of a fillet weld, which at least partially overlaps a pressure-welded area of ​​the expansion band. The invention further relates to a method for producing such a component arrangement.

[0008] DE 10 2009 000 262 A1 discloses a thermal joining method for producing a material-to-material connection between at least two surfaces of one or more workpieces by means of at least one joining seam, in which at least one additional material is used, wherein at least one of the additional materials is already applied to at least one workpiece before joining.

[0009] Patent EP 0 897 183 B1 discloses a high-current switching device comprising two contact plates to be connected to current conductors, at least one movably mounted switching finger attached to one of the contact plates, and contacts arranged on the switching fingers and the other contact plate. Each switching finger is connected to one contact plate via an expansion band and is provided with a housing that absorbs the mechanical loads occurring during switching. The expansion band projects into the housing and extends within the housing to the contact of the switching finger.

[0010] The invention is based on the object of specifying a composite arrangement with at least one expansion band and a method for producing such a composite arrangement.

[0011] The object is achieved according to the invention by a component arrangement which has the features specified in claim 1 and by a method which has the features specified in claim 3.

[0012] Advantageous embodiments of the invention are the subject of the dependent claim.

[0013] A composite arrangement with at least one expansion band comprises a number of metal bands. According to the invention, the metal strips are arranged with at least one respective end with a predetermined step offset one above the other in a stepped manner, wherein the predetermined step offset is greater by a predetermined amount than a height of the respective metal strip, weld seams along the steps of metal strips to be connected are designed as fillet welds and fillet welds of immediately adjacent steps overlap in sections to form an overall weld for connecting the metal strips.

[0014] Furthermore, the invention relates to a method for producing such a composite arrangement.

[0015] With such a composite arrangement, a comparatively low energy input is required for the creation of the fillet welds. Furthermore, material distortion can be reduced by the stepped arrangement of the metal strips and their sequential retraction for the creation of the welds. Due to the sequential welding of the metal strips, the system technology, in particular a laser beam source, can be smaller, thus reducing the acquisition costs for the system technology.

[0016] Because the composite arrangement has the step offset, the weld seam reinforcement is significantly lower than with conventional joining processes, especially welding processes.

[0017] The repeated over-welding, i.e., the overlapping of the fillet welds, results in increased process reliability and thus reduced scrap. A repair process can be carried out analogously to the process used to produce the composite assembly by simply over-welding.

[0018] The composite arrangement makes it possible to generate an enlarged connection cross-section as well as superimposed welding, which can optimize the current-carrying capacity.

[0019] The metal strips can be bonded together in advance as individual parts or welded directly to a component to be joined as a composite arrangement.

[0020] The temperature input into the composite arrangement can be controlled by pauses when the welds are introduced, so that particularly temperature-sensitive components can be joined together.

[0021] Such a composite arrangement is particularly suitable for the power electronics of a vehicle, in particular for components made of copper and / or aluminum to be joined.

[0022] In addition, the arrangement of the metal strips with step offset enables optimized tolerance compensation.

[0023] Furthermore, such a composite arrangement of the metal strips results in new design possibilities, whereby less pre-treatment of the individual metal strips with regard to a burr is required, since in this composite arrangement a burr at the end of a respective metal strip does not lead to the formation of a gap.

[0024] Embodiments of the invention are explained in more detail below with reference to drawings.

[0025] Showing: Fig. 1 schematically shows a perspective view of a section of a stack of metal strips, Fig. 2 schematically shows a perspective view of the section of the stack of metal strips during thermal joining and an enlarged section, Fig. 3 schematically shows a perspective view of an alternative embodiment of a stack of metal strips during thermal joining and an enlarged section.

[0026] Corresponding parts are provided with the same reference numerals in all figures.

[0027] Figure 1 shows a perspective view of a section of metal strips 1 arranged one above the other, which are to be thermally joined to form an expansion band.

[0028] Figure 2 shows a perspective view of a section of a stack of metal strips 1 arranged one above the other during thermal joining and an enlarged section of thermally joined metal strips 1.

[0029] An expansion joint is a flexible busbar made of comparatively thin, packaged metal strips 1, so-called individual foils, made of copper and / or aluminum, and has relatively solid connections (not shown in detail). In particular, the metal strips 1 of a conventional expansion joint are pressure-welded and designed for contact via screw connections.

[0030] In particular, pressure-welded expansion joints are used for electrically connecting components at different heights. These prefabricated parts are connected via screw connections, which, on the one hand, require more space and, on the other hand, exhibit a higher contact resistance during operation of the expansion joint than the busbar.

[0031] In the following, a composite arrangement V and a method for producing the composite arrangement V are described, wherein a thermal joining of the metal strips 1 is realized by means of a welding process, in particular a fusion welding process.

[0032] The method provides that the metal strips 1 are arranged one on top of the other in a stepped manner, wherein a step offset s is greater by a predetermined amount than a height h of a respective metal strip 1. The height h of the respective metal strip 1 simultaneously forms a material thickness of the metal strip 1, wherein the metal strips 1 have essentially the same height h, which is equal to or greater than 0.01 mm and equal to or less than 2.00 mm.

[0033] The step offset s is in particular selected such that it corresponds to a product of the height h of the respective metal strip 1 multiplied by 0.15.

[0034] Due to this step offset s, the metal strips 1 are arranged in a stepped manner, so that, starting from a vertical line and an imaginary line on the end faces of the metal strips 1, an angle δ is spanned that is greater than 45°. The angle δ corresponds to a so-called stair rise, whereby the angle δ can also be referred to as the pitch angle.

[0035] If the metal strips 1 are arranged on top of one another with the step offset s as described above, a corner area per step between two metal strips 1 is melted by means of a laser beam L, whereby a weld seam is introduced as a fillet weld K.

[0036] The insertion of the fillet weld K either begins in a corner area of ​​the lowest steps or in a corner area of ​​the highest steps, with the fillet weld K being inserted successively into the next corner area of ​​the superimposed metal strips 1.

[0037] According to the Figure 2 In the embodiment shown, the insertion of the fillet weld K begins at the bottom right and ends at the bottom left, with the insertion of the fillet weld K beginning at the left and ending at the right in a next corner area of ​​two metal strips 1 arranged one above the other with a step offset s. The next fillet weld K is then inserted from left to right in the next corner area.

[0038] When melting the next step, the previously created fillet weld K is partially melted again, so that an overall weld is created across the steps of the superimposed metal strips 1. This means that the fillet welds K at least partially overlap to create the overall weld.

[0039] The individual fillet welds K can be processed linearly or superimposed with a beam oscillation to widen the overlap.

[0040] Figure 3shows an alternative embodiment of a stack of metal strips 1 arranged one above the other, i.e. an alternative embodiment of the composite arrangement V.

[0041] In this Figure 3 In the embodiment shown, two metal strips 1 are arranged flush with one another. A stepped offset s is formed between each pair of flush-mounted metal strips 1.

[0042] The step offset s is greater than or equal to twice the height h of a metal strip 1.

Claims

1. Composite assembly (V) having at least one expansion strip which comprises a number of metal strips (1), characterized in that - the metal strips (1) are arranged one above the other in a stepped manner, with at least one end having a predetermined step offset (s), the predetermined step offset (s) being greater by a predetermined amount than a height (h) of the relevant metal strip (1), - weld seams along the steps of metal strips (1) to be joined are designed as fillet welds (K) and - fillet welds (K) of immediately adjacent steps overlap in portions to form an overall weld for connecting the metal strips (1).

2. Composite assembly (V) according to claim 1, characterized in that ends of at least two directly adjacent metal strips (1) form a step.

3. Method for producing a composite assembly (V) according to claim 1, characterized in that - the metal strips (1) are arranged one above the other in a stepped manner, each with at least one end having a predetermined step offset (s) which is greater by a predetermined amount than a height (h) of the respective metal strip (1), - weld seams along the steps of metal strips (1) to be joined are designed as fillet welds (K) and - the fillet welds (K) of directly adjacent steps are produced in the metal strips (1) such that they overlap in portions to form an overall weld.