MULTI-STAGE WELDING OF SPLICES USING AN ULTRASONIC WELDING DEVICE.
Patent Information
- Authority / Receiving Office
- MX · MX
- Patent Type
- Patents
- Current Assignee / Owner
- SCHUNK SONOSYST GMBH
- Filing Date
- 2023-01-26
- Publication Date
- 2026-05-19
AI Technical Summary
Existing ultrasonic welding methods struggle to produce splices with relatively large cross sections consistently and homogeneously, often resulting in inhomogeneous joints and damage to conductors, particularly in high-current applications.
A two-stage ultrasonic welding process using an adjustable compaction chamber with variable width and height, allowing for a predetermined tolerance value to ensure uniform distribution of forces and prevent conductor tilting, thereby achieving a homogeneous weld.
The method enhances the reliability and reproducibility of welding large splices by reducing conductor breakage and ensuring uniform resistance, facilitating efficient production of durable and conductive joints suitable for high-current applications.
Smart Images
Figure MX434576B0
Abstract
Description
The present invention relates to a method for welding a splice using an ultrasonic welding device. The invention further relates to a bundle of conductors. BACKGROUND OF THE INVENTION For a wide variety of technical applications, it may be necessary to join two components in a mechanically secure and / or electrically conductive manner. For example, it may be necessary, for various purposes, to join wire strands in a mechanically and electrically conductive way. This allows, for example, the production of wiring harnesses that can be used to connect electrical consumers, for example, within a vehicle, to each other, to a power source, and / or to a control system in an electrically conductive manner. Ultrasonic welding was developed to create substance-to-substance bonds between electrically conductive components, providing them with high strength and good electrical conductivity. It is a special form of friction welding in which the components to be welded are brought into surface contact and moved against each other under low-pressure, high-frequency mechanical vibrations. These vibrations can be generated using a sonotrode, which produces and transmits ultrasonic vibrations, typically at frequencies of 20 kHz to 50 kHz, to at least one of the parts being joined. The resulting plastic flow allows the parts to become impregnated or interlocked near the surface without necessarily melting. Therefore, ultrasonic welding can be used to join parts quickly, inexpensively, and with minimal impact.The welds in which a plurality of electrical conductors are joined together are also called splices. Welding splices with relatively large cross-sections can be difficult because the ultrasonic energy introduced by the sonotrode is generally introduced into the overall volume of the splice only through one surface of the conductors to be welded, this surface being in contact with a surface of the sonotrode, resulting in a possibly non-homogeneous distribution of ultrasonic energy and, therefore, a non-homogeneous weld of the conductors. For welding splices with relatively large cross-sections, a two-stage ultrasonic welding process can be used, in which, for example, a smaller splice is welded first, and then, in a subsequent stage, this splice is welded with one or more additional electrical conductors to form a larger splice with the desired total cross-section. The corresponding procedures are described, for example, in documents WO 2015 / 007619 A1 and DE 2011 014 801 B4. Document DE 11 2014 002 908 T5, for example, describes an ultrasonic welding process in which a wire beam is welded in a plurality of welding processes and the wire beam is rotated with respect to the sonotrode between two welding processes. MA.aZUZJ / UUl I z / SUMMARY OF THE INVENTION AND FAVORABLE IMPLEMENTATIONS There may be a need for a welding method to weld a splice using an ultrasonic welding device, whereby splices, particularly those with relatively large cross-sections, can be produced with consistently high quality. A conductor bundle may also be required, in which a plurality of high-quality electrical conductors are welded together to form a splice. This requirement can be met by the subject matter of the independent claims. The favorable embodiments are defined in the dependent claims and in the following description. The first aspect of the invention relates to a method for welding a splice using an ultrasonic welding device. The ultrasonic welding device comprises a sonotrode for generating ultrasonic vibrations, an anvil, a first side element, a second side element, and a compaction chamber, the height of which is adjustable by varying the distance between the sonotrode and the anvil, and the width of which is adjustable by varying the distance between the first side element and the second side element. The method comprises the following steps, which may preferably be performed in the order indicated: placing the first conductive parts of at least two electrical conductors to be welded into the compaction chamber; adjusting the width of the compaction chamber to a predetermined value for a first welding process;Perform the first welding process by activating the sonotrode and compressing the first conductive parts between the sonotrode and the anvil, welding the first conductive parts together to form a first splice; place a second conductive part of at least one other electrical conductor to be welded and the first splice in the compaction chamber; adjust the width of the compaction chamber to a predetermined value for a second welding process, the width of the compaction chamber for the second welding process being greater by a predetermined tolerance value than the width of the compaction chamber for the first welding process; and perform the second welding process by reactivating the sonotrode and compressing the first splice and the second conductive part between the sonotrode and the anvil, welding the first splice and the second conductive part together to form a second splice. The sonotrode and anvil in the ultrasonic welding device can be arranged to be movable relative to each other in at least one direction, for example, to increase or decrease the vertical and / or horizontal distance between them. In this case, for example, the sonotrode could be fixed and the anvil movable. However, it is also possible for the sonotrode to be movable and the anvil fixed. Alternatively, both the sonotrode and the anvil could be movable. A side element, for example, can be a side displacer (= side slider) or a surface plate (= contact plate). The first side element and the second side element can be arranged in the ultrasonic welding device to be movable relative to each other in at least one direction. For example, the first side element can be movable in the horizontal direction, while the second side element is fixed in the horizontal direction, and vice versa. Alternatively, both MA.a.ZUZJ / UUl I ¿ / lateral elements can be movable in a horizontal direction. It is also possible that at least one of the two lateral elements is in turn movable in a vertical direction. The compaction chamber may be bounded by the sonotrode, the anvil, the first side element, and the second side element on four different sides, at least during a welding process. The compaction chamber may be open on one or more sides. For example, the compaction chamber may be closed at the top by the anvil during a welding process. By moving the anvil away, the compaction chamber may be opened at the top, for example, before a welding process to introduce the electrical conductors to be welded into the compaction chamber, or after a welding process to remove the welded electrical conductors from the compaction chamber.For example, to facilitate insertion or extraction, in addition to moving the anvil further away, at least one of the two side elements can be retracted, so that the distance between the first side element and the second side element increases accordingly. An electrical conductor can be a strand, i.e., a composite of multiple individual wires, or a single wire within that strand, i.e., a single solid conductor. The electrical conductor may be partially coated with an electrically insulating material. Consequently, a conductive part to be welded can be an uncoated portion of the electrical conductor, located at one end or between two ends. The conductive parts to be welded can have different or the same cross-sectional areas. The electrical conductor, for example, can be made of metal or another electrically conductive material. Alternatively, the electrical conductor can be a rigid component, such as a terminal block, busbar, or similar item. A splice can generally be understood as a joint produced by welding at least two connecting pieces. For example, in a first welding process, a plurality of strands, i.e., a plurality of composite wires, can be welded together to form the first splice. However, it is also possible that in the first welding process, individual wires of the same strand are welded together to form the first splice, which is also called compaction. In this case, the first splice can be understood as a compacted portion of this strand. In other words, a splice can comprise a single conductor (formed by a plurality of individual wires) or several conductors. As part of the process, the first conductive parts of at least two electrical conductors to be welded are placed in the compaction chamber. To do this, the compaction chamber can be opened, for example, by moving the anvil and / or at least one of the two side elements. Simultaneously, the width of the compaction chamber can be adjusted to the predetermined value for the first welding process. In the closed state, the compaction chamber can be limited both in height, by the sonotrode and the anvil, and in width, by the two side elements. The first splice and / or the second splice may have a rectangular cross-section, that is, at least approximately rectangular. Rectangular here means that the cross-section is MA.aZUZJ / UUl I ¿ / flattens on at least two opposite sides. For example, the cross-section can be flattened on all four sides. However, a barrel-shaped cross-section is also possible. For example, the dimensions of the rectangular cross-section can correspond to the dimensions of the compaction chamber in its closed state after welding. When the sonotrode is activated, it vibrates and introduces welding energy into the parts of the conductor to be welded. For example, the width of the compaction chamber can be adjusted to the nominal width of the first or second joint, respectively. The nominal width can be the maximum desired width of the first or second joint, respectively. The width of the compaction chamber can remain constant throughout the welding process. However, it is also possible for the width of the compaction chamber to change during welding. An additional electrical conductor can be an additional individual wire or an additional strand, i.e., a welded or unwelded composite of additional individual wires. It is also possible for the second conductive part to be an additional splice into which a plurality of additional electrical conductors are welded. The additional splice may have been produced, for example, by ultrasonic welding. For instance, the second splice may be welded from the first splice, from at least one unwelded strand, and / or from at least one compacted strand. The method involves adjusting the compaction chamber width to a predetermined value for a second welding process. The compaction chamber width for the second welding process is greater by a predetermined tolerance than the compaction chamber width for the first welding process. This tolerance value can be selected so that the first splice has a slight clearance between the first and second side members after the compaction chamber width has been adjusted. This clearance prevents the first splice from tilting or becoming stuck in the compaction chamber. This allows for a defined distribution of forces across the entire cross-section of the first splice during the subsequent welding process. In this way, a highly homogeneous, and therefore very durable and conductive, welded joint can be produced.The clearance can also reduce welding force losses by preventing direct contact between the first splice and the two side elements. An excessively large clearance should not be selected to prevent material, such as individual wires, from escaping the first splice during the subsequent welding operation and / or to ensure the resulting splice does not have any steps or excessively large steps. The width of the compaction chamber for the second welding process can be adjusted in the same way as for the first welding process. For example, depending on the selected tolerance value, the second joint can be divided vertically into two joint sections of different widths, each with a rectangular cross-section, i.e., at least approximately rectangular. ML / a / ZUZJ / UUl I z / Tests have shown that, in addition to reducing single-conductor breakage and discoloration, it was possible to increase the reliability of the process due, among other things, to more uniform connector resistance. A more even distribution of conductors across the splice width was also observed. Furthermore, the splice structure proved easy to reproduce. Without restricting the scope of the invention, it can be considered that the ideas and possible features related to the embodiments of the invention are based, among other things, on the thoughts and findings described below. According to one embodiment, the second conductive part is positioned between the first splice and the sonotrode. The first splice can be initially removed from the compaction chamber before the second conductive part is positioned. To do this, the compaction chamber can be opened accordingly (see above). The second conductive part can then be placed over the sonotrode. Subsequently, the first splice can be placed over the second conductive part to avoid direct contact between the first splice and the sonotrode. In the subsequent welding process, the welding energy is introduced into the first splice indirectly through the second conductive part. This can prevent the re-experiencing of high thermal and mechanical stress on the first splice. Among other things, this can prevent or at least reduce breaks in individual wires or non-homogeneous regions in the weld metal. According to one embodiment, the default tolerance value is at least 0.01 mm. According to an alternative embodiment, the default tolerance value is at least 0.05 mm. According to another alternative embodiment, the default tolerance value is at least 0.1 mm. According to one embodiment, the default tolerance value is a maximum of 2 mm. According to an alternative embodiment, the default tolerance value is a maximum of 5 mm. By using a tolerance value within the specified orders of magnitude, it is possible, on the one hand, to prevent tilting or jamming of the first splice in the compaction chamber. On the other hand, it is possible to prevent the material from being pushed beyond the first splice during the second welding process, which could reduce the quality of the welded joint, and / or to prevent the second splice from having excessively large steps. This simplifies subsequent processing of the conductor bundle, such as covering the second splice with heat-shrink tubing. According to one embodiment, the second splice has a cross-section of at least 3 mm². According to another embodiment, the second splice has a cross-section of at least 20 mm². According to an alternative embodiment, the second splice has a cross-section of at least 50 mm². According to one embodiment, the second splice has a nominal width of at least 2 mm. According to an alternative embodiment, the second splice has a nominal width of at least 5 mm. According to another alternative embodiment, the second splice has a nominal width of at least 10 mm. As previously mentioned, it has been observed that forming splices of relatively large diameters and / or with relatively complex structures using ultrasonic welding can be difficult, as insufficiently homogeneous joints can occur between the conductors and / or ML / a / ZUZ J / UU112 Damage to the conductors may occur, especially near the splice surfaces. Tests have shown that the method proposed here is particularly suitable for welding electrical conductors with relatively large cross-sections, such as those used, for example, for high-current connections in electric or hybrid vehicles. According to one embodiment, the width of the compaction chamber for the first welding process is equal to the nominal width of the first splice. According to one embodiment, the width of the compaction chamber for the second welding process is equal to the nominal width of the second splice. The nominal width of a splice can generally be understood as the maximum desired width of the splice. By adjusting the width of the compaction chamber to the nominal width of the first or second splice, it can be easily ensured that the first or second splice is no wider than this nominal width at its widest point. According to one embodiment, the width of the compaction chamber for the first welding process is equal to the difference between the nominal width of the second splice and a predetermined tolerance value. In other words, the nominal width of the first splice can be determined based on the nominal width of the second splice. The width difference between the two splices can be large enough to prevent the first splice from tilting when it is inserted into the second conductor segment to weld the second splice. Depending on the hardness of the joining material and the welding parameters, the joining pieces may be flattened during a welding operation to a portion of the compaction chamber width or to the entire width of the compaction chamber. In the latter case, the first or second joint can be produced very easily and reproducibly with a desired final width by adjusting the compaction chamber width accordingly. According to one embodiment, the cross-sectional area of the second conductor part is at least as large as the respective smaller cross-sectional area of the first conductor parts. As a result, a relatively complex and / or relatively large splice can be constructed with only two welding processes. According to one embodiment, the method further comprises arranging a third conductive portion of at least one additional electrical conductor to be welded and the second splice in the compaction chamber, adjusting the width of the compaction chamber to a predetermined value for a third welding process, the width of the compaction chamber for the third welding process being greater by an additional predetermined tolerance value than the width of the compaction chamber for the second welding process, and performing the third welding process by reactivating the sonotrode and compressing the second splice and the third conductive portion between the sonotrode and the anvil, welding the second splice and the third conductive portion of the at least one additional electrical conductor to form a third splice.In some cases, such as when splicing with very large cross-sectional areas and / or very complex structures, it may be necessary to weld in three or more steps to make the most efficient use of the available welding power. For example, the third conductive part can be positioned between the second splice and the sonotrode. This prevents direct contact between the second splice and the sonotrode. In the subsequent welding process, the welding energy is introduced into the second splice indirectly through the third conductive part. This prevents the second splice from experiencing high thermal and mechanical stress again. Among other things, this can prevent or at least reduce breaks in individual wires or non-homogeneous regions in the weld metal. Similar to the tolerance value mentioned earlier, an additional tolerance value can be selected to ensure that the second splice has a small clearance between the first and second lateral elements after adjusting the compaction chamber width. This prevents the second splice from tilting or becoming stuck in the compaction chamber and guarantees a defined force distribution across the entire cross-section of the second splice. According to one embodiment, each of the electrical conductors is a partially sheathed strand, like a partially stripped wire, and each of the conductive parts is a portion of the unsheathed strand. Thus, for example, convenient cable assemblies or harnesses for high-current applications can be produced very efficiently with durable and highly conductive connections. A second aspect of the invention relates to a conductor bundle comprising electrical conductors welded together at a splice. The splice is divided vertically into two splice sections, each having a rectangular shape, i.e., a cross-section at least approximately rectangular. In this case, the two splice sections differ from each other in their mean width by at least 0.01 mm or, alternatively, by at least 0.1 mm. According to an alternative embodiment, the two splice sections may differ from each other in their average width by at least 0.05 mm. The conductive beam may preferably have been produced by a process according to an embodiment of the first aspect of the invention. However, the conductive beam may also have been produced by another suitable welding process. An average width can be understood as an average value for the relevant width of the splice portions, determined based on a plurality of measurements. For example, a plurality of width values can be measured at various measurement points distributed across the relevant splice section. These width values can then be used to calculate an arithmetic mean and / or a median as the average width. In other words, the splice pieces may form a step or be separated from each other by a step in a region where the splice pieces are adjacent to each other in the direction of the splice height. Depending on the lateral displacement of the two splice pieces, the splice may have a single step or two steps on opposite sides. This step may extend substantially transversely to the direction of the splice height, particularly in a direction orthogonal to it. For example, the step may be visible to the naked eye. The step may be rounded, flattened, or have its edges sharpened. For example, the step may be rounded with a radius that is larger than the largest radius of an individual wire in the conductor bundle. In other words, the step may be wider than the maximum diameter of an individual wire in the conductor bundle.For example, the step can be at most 2 mm wide, preferably up to a maximum of 5 mm. The overall width of the step(s) can preferably be at least 0.05 mm or, for example, at least 0.1 mm. In particular, the overall width of the step(s) can approximately correspond to the tolerance value set during the splice production, as described above. A bundle of conductors produced preferably by a process according to an embodiment of the first aspect of the invention. According to one embodiment, the splice is produced by ultrasonic welding. As a result, the conductor bundle can be produced without fusing the conductive material and, therefore, compared to common fusion welding processes, has relatively low production costs. According to one embodiment, each of the electrical conductors is a partially insulated wire; the uninsulated portions of the wires are welded together to form the splice. In other words, each of the electrical conductors can be a partially stripped cable. Each wire can have a relatively large conductive cross-sectional area, for example, at least 10 mm². As a result, the conductor bundle can be used for the protected transmission or distribution of currents, particularly relatively high currents of, for example, at least 100 A, as in electric or hybrid vehicles. It should be noted that the possible features and advantages of the embodiments of the invention are described partly in relation to a method for welding a splice using an ultrasonic welding device, partly in relation to an ultrasonic welding device capable of carrying out said method, and partly in relation to a conductor bundle that may have been produced by said method. A person skilled in the art will recognize that the features described for individual embodiments can be transferred to other embodiments in an analogous and appropriate manner, and can be adapted and / or interchanged to arrive at other embodiments of the invention and possibly to synergistic effects. BRIEF DESCRIPTION OF THE DRAWINGS Favorable embodiments of the invention are further explained below with reference to the accompanying drawings, in which neither the drawings nor the explanations should be construed as a limitation of the invention. ML / a / ZUZ J / UU1 I z / Figure 1 shows a schematic illustration of an ultrasonic welding device according to an embodiment of the invention with the compaction chamber open before the first welding process. Figure 2 shows the ultrasonic welding device of Figure 1 with the first side element extended. Figure 3 shows the ultrasonic welding device from Figure 1 with the compaction chamber closed during the first welding process. Figure 4 shows the ultrasonic welding device of Figure 1 with the compaction chamber closed during the first welding process. Figure 5 shows the ultrasonic welding device of Figure 1 with a closed compaction chamber during the second welding process. Figure 6 shows a flowchart of a method for welding a splice using an ultrasonic welding device according to an embodiment of the invention. Figure 7 shows a schematic illustration of a bundle of conductors according to an embodiment of the invention in cross-section. Figure 8 shows a side view of the conductor bundle in Figure 7. The figures are merely schematic and are not to scale. Identical reference numbers on the various drawings indicate identical features or features that have the same effect. DESCRIPTION OF FAVORABLE ACHIEVEMENTS Figure 1 shows a schematic illustration of an ultrasonic welding device 100 with a sonotrode 102 for generating ultrasonic vibrations, an anvil 104, a first side element 106, for example, a side displacer, and a second side element 108, for example, a surface plate. The sonotrode 102, the anvil 104, the first side element 106, and the second side element 108 define the compaction chamber 110, into which the first conductive portions 112 of a plurality of electrical conductors 114 to be welded are inserted. Alternatively, only the first conductive portions 112 of a single electrical conductor 114 can be inserted for compaction, for example. Figure 1 shows the compaction chamber 110 in an open state, where it is open to the side opposite the sonotrode 102 and is bounded on three sides only by the sonotrode 102, the first side element 106, and the second side element 108. The first conductive parts 112 can thus be inserted into the compaction chamber 110 from above, for example, manually by an operator or automatically by a gripping arm or similar device. Contrary to the schematic illustration shown in Figure 1, the side elements 106 and 108 can also be adjusted to allow some air between the first conductive part 112 and the respective end faces of the two side elements 106 and 108 during insertion. Alternatively, the side displacer 106 can be pre-set to a specific weld width before the electrical conductors 114 are inserted.In some cases, this facilitates insertion. ML / a / ZUZ J / UU1 I ¿ / For example, the compaction chamber 110 may be closed by the anvil 104 on the opposite side to the sonotrode 102, as shown in Figures 3 and 5. A width B of the compaction chamber 110 is predetermined by a distance between the first lateral element 106 and the second lateral element 108 in the xy direction. This distance can be varied in the x-direction by moving the first lateral element 106 and / or the second lateral element 108. In Figure 1, for example, only the first lateral element 106 is movable in the x-direction, while the second lateral element 108 is fixed in the x-direction. A height H of the compaction chamber 110 is predetermined by the distance between the sonotrode 102 and the anvil 104 in the y-direction when the compaction chamber 110 is closed and can be varied by moving the sonotrode 102 and / or the anvil 104 in the y-direction. The height H is shown in Figures 3 and 5. In Figure 1, for example, only the anvil 104 is movable in the y-direction, while the sonotrode 102 is fixed in the y-direction. For instance, the second side element 108 can be movable in the y-direction, while the anvil 104 can be mechanically coupled to the second side element 108. Thus, the anvil 104 can move in the y-direction along with the second side element 108. Electrical conductors 114 can be individual wires of one or more cables. For example, each electrical conductor 114 can be partially covered with an insulating material. Thus, each electrical conductor 114 can be an individual cable. The first conductive parts 112 can be uncovered parts of such a cable. Alternatively, a plurality of electrical conductors 114 can be combined into a single wire or a plurality of wires. For example, all the electrical conductors 114 can also be combined into a single wire. In turn, such a wire can be partially covered with an insulating material; that is, it can be a cable. The first conductive parts 112 can be arranged in multiple layers on a sonotrode surface 116 of the sonotrode 102. Ultrasonic vibrations can be coupled to the first conductive parts 112 through the sonotrode surface 116, causing the first conductive parts 112 to bond together in a positive substance junction, i.e., to weld into a splice. The ultrasonic welding device 100 is configured to weld the first conductive parts 112 in two consecutive welding processes. To do this, the first side element 106 can be extended a short distance after the insertion of the first conductive parts 112 to adjust the width B to a predetermined value for a first welding process (see Figure 2). For example, the anvil 104 can be further lowered in the y direction by lowering the second side element 108 and moving in the x direction towards the first side element 106. For example, the first side element 106 can act as a stop for the anvil 104 in the x direction (see figure 3). MA.aZUZJ / UUl I z / The sonotrode 102 is activated for welding, and the first conductive portions 112 are compressed using the sonotrode 102 and the anvil 104. As a result, the first conductive portions 112 are welded into a first splice 300 (see Figure 3). In this case, the width of the first splice 300 can correspond to the width B of the compaction chamber 110. That is, the nominal width of the first splice 300 can be predetermined by the width B of the compaction chamber 110. After welding the first splice 300, the compaction chamber 110 can be reopened, for example by retracting the first side element 106 and / or the anvil 104. The first splice 300 can now be removed from the compaction chamber 110, and the second conductive parts 400 of a plurality of additional electrical conductors 402 can be placed on the surface of the sonotrode 116 (see Figure 4). The second conductive parts 400 can be uninsulated portions of one or more additional cables. The first splice 300 is inserted into the second conductive parts 400 so that the surface of the sonotrode 116 makes contact with the second conductive parts 400 but not with the first splice 300. Before, during, or after the insertion of the second conductive parts 400 and the first splice 300, the width B is adjusted to a predetermined value for a second welding process. The predetermined value for the second welding process is greater by a predetermined tolerance value ΔB than the predetermined value for the first welding process. The tolerance value ΔB is selected so that the first splice 300 has a slight clearance between the first side member 106 and the second side member 108. This clearance prevents the first splice 300 from becoming stuck or tilted between the first side member 106 and the second side member 108 (see Figure 4). Subsequently, the second conductive parts 400 and the first splice 300 are welded together in the second welding process to form a second homogeneous splice 500, which may be significantly larger than the first splice 300 (see Figure 5). In this case, the width of the first splice 500 may correspond to the width B of the compaction chamber 110. That is, the nominal width of the second splice 500 may be predetermined by the width B of the compaction chamber 110. It is possible that, in a third welding process similar to the first and second welding processes, the second 500 splice is welded with a third conductive part of at least one additional electrical conductor to form a third splice. Figure 6 illustrates the basic sequence of the ultrasonic welding method described with reference to Figures 1 to 5. In step S10, the first conductive parts 112 of at least two electrical conductors 114 to be welded are placed in the compaction chamber 110. In step S20, the width B of the compaction chamber 110 is set to the default value for the first welding process. ML / a / ZUZJ / UUl I z 7 In step S30, the first welding process is performed by activating the sonotrode 102 and compressing the first conductive parts 112 between the sonotrode 102 and the anvil 104, welding the first conductive parts 112 together to form the first splice 300. In step S40, a second conductive part 400 of at least one other electrical conductor 402 to be welded is arranged between the first splice 300 and the sonotrode 102 in the compaction chamber 110. In step S50, the width B of the compaction chamber 110 is adjusted to the default value for the second welding process, with the width B of the compaction chamber 110 for the second welding process being larger by a default tolerance value ΔB than the width B of the compaction chamber 110 for the first welding process. In step S60, the second welding operation is performed by reactivating the sonotrode 102 and compressing the first splice 300 and the second conductive part 400 between the sonotrode 102 and the anvil 104, welding the first splice 300 and the second conductive part 400 together to form the second splice 500. The second 500 splice may have one or two steps on its side surfaces due to the different weld widths (see also figure 7). Figure 7 shows a cross-section through a bundle of conductors 700 along a line of section AA shown in Figure 8. The bundle of conductors 700, for example, may have been produced by the method described above with reference to Figures 1 to 6 and comprise conductors 114 and 402 which are welded together at the second splice 500 (see also Figure 8). The second splice 500 is divided in the direction of its height H' into a first splice section 702 and a second splice section 704, each of which has an approximately rectangular cross-section. The splice pieces 702 and 704 differ from each other in the direction of their width B' by an average of at least 0.01 mm, preferably by at least 0.1 mm. The splice pieces 702 and 704 can be offset relative to each other in the direction of their width B' so that a step is formed on one or both sides of the second splice 500. In Figure 7, the second splice 500 has, for example, a left step 706 and a right step 706' which can have different widths depending on the offset of the splice pieces 702 and 704. For example, the sum of the respective widths of steps 706 and 706' can be at least 0.2 mm. Therefore, steps 706 and 706' can be visible to the naked eye. It can also be observed in Figure 8 that each of the electrical conductors 114, 402 is a partially coated wire and the wires are welded together in an uncoated area, comprising the conductive parts 112, 400 to form the second splice 500. The width B' of the wider splice piece 702, 704 can be equal to the nominal width of the second splice 500. The height H' can be equal to the nominal height of the second splice 500. Finally, it should be noted that terms such as "having," "comprising," etc., do not exclude other elements or steps, and the term "a" does not exclude a plurality. It should also be noted that the features or steps described with reference to one of the preceding exemplary embodiments may also be used in combination with other features or steps from other exemplary embodiments described previously. The reference numbers in the claims should not be considered a limitation. List of reference numbers 100 Ultrasonic Welding Device 102 Sonotrode 104 Anvil 106 First lateral element 108 Second lateral element 110 Compaction chamber 112 First driving part 114 Electrical conductor 116 Sonotrode surface 300 First splice 400 Second part driver 402 Other electrical conductor 500 Second junction 700 Conductor Bundle 702 First splice section 704 Second splice section 706 Left step 706' Right step B Width of the compaction chamber B' Width of the second splice ΔB Tolerance value H Height of the compaction chamber H' Height of the second joint X Address “x” And Direction “and”
Claims
1. A method for welding a splice (500) using an ultrasonic welding device (100), wherein the ultrasonic welding device (100) has a sonotrode (102) for generating ultrasonic vibrations, an anvil (104), a first side element (106), a second side element (108), and a compaction chamber (110), the height (H) of which is adjustable by varying a distance between the sonotrode (102) and the anvil (104), and the width (B) of which is adjustable by varying a distance between the first side element (106) and the second side element (108), characterized in that the method comprises: arranging the first conductive parts (112) to be welded of at least two electrical conductors (114) in the compaction chamber (110); adjusting the width (B) of the compaction chamber (110) to a predetermined value for a first welding process;performing the first welding process by activating the sonotrode (102) and compressing the first conductive parts (112) between the sonotrode (102) and the anvil (104), wherein the first conductive parts (112) are welded together to form a first splice (300); arranging a second conductive part (400) to be welded from at least one other electrical conductor (402) and the first splice (300) in the compaction chamber (110); adjusting the width (B) of the compaction chamber (110) to a predetermined value for a second welding process, wherein the width (B) of the compaction chamber (110) for the second welding process is greater, by a predetermined tolerance value (ΔB), than the width (B) of the compaction chamber (110) for the first welding process;and perform the second welding process by reactivating the sonotrode (102) and compressing the first splice (300) and the second conductive part (400) between the sonotrode (102) and the anvil (104), wherein the first splice (300) and the second conductive part (400) are welded together to form a second splice (500).; 2. The method according to claim 1, characterized in that the second conductive part (400) is arranged between the first splice (300) and the sonotrode (102).
3. The method according to claims 1 and 2, characterized in that the predetermined tolerance value (ΔB) is at least 0.01 mm; or the predetermined tolerance value (ΔB) is at least 0.1 mm.
4. The method according to one of the preceding claims, characterized in that the predetermined tolerance value (ΔB) is at most 2 mm; or the predetermined tolerance value (ΔB) is at most 5 mm.
5. The method according to one of the preceding claims, characterized in that the second splice (500) has a cross-sectional area of at least 3 mm²; or the second splice (500) has a cross-sectional area of at least 50 mm². MA.aZUZJ / UUl I ¿ / 6. The method according to one of the preceding claims, characterized in that the second splice (500) has a nominal width of at least 2 mm; or the second splice (500) has a nominal width of at least 10 mm.
7. The method according to one of the preceding claims, characterized in that the width (B) of the compaction chamber (110) for the first welding process is equal to the nominal width of the first splice (300); and / or where the width (B) of the compaction chamber (110) for the second welding process is equal to the nominal width of the second splice (500).
8. The method according to claim 7, characterized in that the width (B) of the compaction chamber (110) for the first welding process is equal to a difference between the nominal width of the second splice (500) and the predetermined tolerance value (ΔB).
9. The method according to one of the preceding claims, characterized in that a cross-sectional area of the second conducting part (400) is at least as large as the respective smaller cross-sectional area of the first conducting parts (112).
10. The method according to any of the preceding claims, characterized in that it further comprises: arranging a third conductive part of at least one additional electrical conductor to be welded and the second splice (500) in the compaction chamber (110); adjusting the width (B) of the compaction chamber (110) to a predetermined value for a third welding process, wherein the width (B) of the compaction chamber (110) for the third welding process is greater, by an additional predetermined tolerance value, than the width (B) of the compaction chamber (110) for the second welding process; and performing the third welding process by reactivating the sonotrode (102) and compressing the second splice (500) and the third conductive part between the sonotrode (102) and the anvil (104), wherein the second splice (500) and the third conductive part are welded together to form a third splice.
11. The method according to one of the preceding claims, characterized in that each of the electrical conductors (114, 402) is a partially coated wire and each of the conductive parts (112, 400) is an uncoated portion of the wire.
12. A bundle of conductors (700), preferably produced by a method according to one of the preceding claims, characterized in that the bundle of conductors (700) comprises electrical conductors (114, 402) welded together at a splice (500); wherein the splice (500) is divided along its height (Hj) into two splice pieces (702, 704), each having a rectangular cross-section; wherein the two splice pieces (702, 704) differ from each other in their mean width by at least 0.01 mm, preferably by at least 0.1 mm. MA / a / ZUZ J / UU1 I z / 13. The conductor bundle (700) according to claim 12, characterized in that the splice (500) is produced by ultrasonic welding.
14. The conductor bundle (700) according to claim 12 or 13, characterized in that each of the electrical conductors (114, 402) is a partially coated wire and the 5 uncoated parts (112, 400) of the wires are welded together to form the splice (500).