Welding method

Abstract

To provide a welding method for welding a conductor to a work-piece.SOLUTION: A conductor 1 includes a first metal 2, and a work-piece includes a second metal. First insulators 5 of the conductor are removed over a predetermined length. Next, a bead is formed in a peeled-off region of the conductor. Then the conductor is pressed against the work-piece, which causes mechanical contact in a weld region between the conductor and the work-piece, where the weld region is arranged in a region of the bead. Finally the conductor is welded to the work-piece by laser welding in the weld region.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a welding method and to an arrangement of conductors in a workpiece. [Background technology]

[0002] It is known from the prior art to weld a conductor to a workpiece. In this case, the conductor can have one or more cores, which are surrounded by an insulating material. To weld the conductor to the workpiece, the insulation of the conductor is stripped in one area, i.e. the insulating material is removed. The stripped area of ​​the conductor is then pressed against the workpiece, for example by holding-down devices. In the case of multi-core conductors, several mutually insulated conductive areas may be placed on the workpiece for this purpose. After the conductor is pressed against the workpiece, at least one core of the conductor is in mechanical contact with the workpiece or at least one conductive area of ​​the workpiece, so that this core can be welded to the workpiece by a laser welding process.

[0003] Since the conductor is separated from the workpiece by the insulating material, the pressing of the conductor must be performed so that the core of the conductor is pressed against the workpiece with a certain force. The pressing device must be able to accommodate this and therefore can only be used in the stripping area of ​​the conductor. Summary of the Invention [Problem to be solved by the invention]

[0004] One problem addressed by the present invention is to provide an improved welding method. Another problem addressed by the present invention is to provide a corresponding welded arrangement of conductors in a workpiece. [Means for solving the problem]

[0005] These problems are solved by the method for welding a conductor to a workpiece and by the arrangement of the conductor on the workpiece according to the independent patent claims. Advantageous configurations are specified in the dependent patent claims.

[0006] In a method for welding a conductor to a workpiece, the conductor includes a first metal and the workpiece includes a second metal. To weld the conductor to the workpiece, the following steps are performed: First, remove a length of insulation from the conductor. Next, form a bead in the stripped area of ​​the conductor. In this case, the stripped area of ​​the conductor may be the area of ​​the conductor from which the insulation has been removed.

[0007] The conductor is then pressed against the workpiece, which creates a mechanical contact in the weld area between the conductor and the workpiece, where the weld area is located in the area of ​​the bead. The conductor is then laser welded to the workpiece in the weld area.

[0008] The invention is therefore based on the central idea of ​​shortening the distance between the conductor and the workpiece by means of a bead formed on the conductor and arranged in the stripping area of ​​the conductor. This shortening of the distance is due to the necessary deformation of the conductor, which occurs not only when pressing takes place, but already during the formation of the bead. In this case, the bead can be configured in such a way that it forms a convex part of the conductor that faces the workpiece, thus shortening the distance between the conductor and the workpiece. In addition to the bead, further deformations of the conductor can be produced during pressing of the conductor. The welding process can be improved in particular when no gap is formed, i.e. when the conductor lies in direct contact with the workpiece.

[0009] In one embodiment of the method, the workpiece includes several conductive regions, the conductors being part of a multi-core conductor, and during the welding process, insulation is removed in all cores of the multi-core conductor, beads are formed in all cores of the multi-core conductor, and in a subsequent laser welding process, the cores are welded in turn to the conductive regions.

[0010] This enables an efficient process for welding multi-core conductors to conductive areas of a work piece, such as those used in battery manufacturing.

[0011] In one embodiment of the method, after the laser welding, the conductor is welded to the workpiece by laser welding in a further weld area. Thus, the conductor, or each core in the case of a multi-core conductor, is welded to the workpiece in the weld area and in the further weld area, respectively, resulting in a more reliable welded connection.

[0012] In one embodiment of the method, the bead is formed in such a way that during pressing, the conductor first lies in contact with the welded area and not in contact with the further welded area. Thermal expansion of the conductor during laser welding in the welded area leads to a deformation of the conductor, so that the conductor then lies in contact with the further welded area and can be welded there to the workpiece as well. This deformation of the conductor occurs, for example, because the bead is configured such that the conductor is closer to the workpiece in the welded area than in the further welded area, i.e. the conductor is in contact with the workpiece specifically in the welded area and not in contact with the workpiece in the further welded area.

[0013] This allows the thermal expansion of the conductor during laser welding to be similarly utilized, with the overall effect of positioning the conductor in more favorable contact with the work piece.

[0014] In one embodiment of the method, the conductor is a flat conductor having a rectangular cross section. Such a conductor is particularly suitable for the described welding method.

[0015] In one embodiment, the pressing is performed in the stripping region of the conductor, for example by a pressing device that contacts the conductor in the welding region and presses the conductor against the workpiece, or for example by an air stream impinging on the stripping region.

[0016] In one embodiment of the method, the pressing is performed outside the stripped area. This can also be done, for example, by a pressing device or an air flow. For example, a pressing device may be used in the stripped area of ​​the conductor and a pressing device may be used in the non-striped area of ​​the conductor. If the conductor is pressed outside the stripped area, the size of the stripped area can be reduced.

[0017] In one embodiment of the method, the laser welding in the weld area is performed by several weld points, as well as for further weld areas. In the case of laser welding, it is common to set several weld points at the weld location, for example in the form of a spiral. Due to the bead, this can be done very efficiently in the described welding method, since, for example, no pressing device is required near the weld area.

[0018] In one embodiment of the method, the depth of the bead corresponds approximately to the thickness of the insulation. In particular, the depth of the bead corresponds to the thickness of the insulation, so that the bead is configured such that the conductor contacts the workpiece in the weld area even if it would otherwise be placed in contact with the insulation of the workpiece, and the resulting displacement of the conductor is directed towards the workpiece. This configuration is particularly suitable for pressing the conductor against the insulation or for pressing the conductor with an air flow.

[0019] In one embodiment of the method, the formation of the bead is performed by drop forging, where the conductor is placed in a mold containing at least two dies and a forging operation is used to form the bead on the conductor, which allows for a simple and efficient process of forming the bead, and the mold used in drop forging allows for good reproducibility of the forging results.

[0020] In one embodiment of the method, the first metal comprises or is composed of aluminum or copper. In one embodiment of the method, the second metal comprises or is aluminum. In particular, these materials are suitable for use with the proposed laser welding process. A light source capable of inducing the emission of energy and / or power and / or wavelength suitable for welding the metals to be welded together can be used as a laser in the laser welding process. Such suitable laser welding processes are known from the prior art.

[0021] The present invention also includes an arrangement of a conductor on a workpiece, the conductor comprising a first metal and the workpiece comprising a second metal. The conductor and the workpiece are welded at a weld area, the conductor being stripped of insulation at the weld area and comprising a bead. Such an arrangement of a conductor welded to a workpiece can be easily formed by the welding method according to the present invention. The bead clearly indicates that the welding method according to the present invention has been used.

[0022] In one embodiment of the arrangement, the depth of the bead approximately corresponds to the thickness of the insulation of the conductor outside the weld area, which allows a particularly simple manufacture of the arrangement.

[0023] The problems addressed by the invention, the technical implementation of the solution, and the advantages of the invention will become apparent from the exemplary embodiments described below with reference to the drawings. [Brief description of the drawings]

[0024] [Figure 1] FIG. 2 illustrates a conductor at the start of the welding process. [Diagram 2] FIG. 2 shows the conductor after stripping of the insulation. [Diagram 3] FIG. 2 shows the conductor after it has been placed in a mold. [Figure 4] FIG. 2 shows the conductor after the formation of the bead. [Diagram 5] FIG. 13 shows the conductor after pressing and during the welding operation. [Figure 6] FIG. 1 shows a multi-core conductor that has been stripped. [Figure 7] FIG. 2 shows a multi-core conductor having beads. [Figure 8] FIG. 2 shows a multi-core conductor after welding. [Figure 9] FIG. 13 shows further compressed conductors. [Figure 10] FIG. 2 shows a compressed conductor during a welding operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] 1 is a cross-sectional view of a conductor 1. In this case, the conductor 1 comprises a first metal 2. An insulator 5 is attached to the first metal 2 of the conductor 1 so as to insulate the first metal 2.

[0026] 2 shows the conductor 1 after the insulation 5 of the conductor 1 has been removed over a predetermined length 6. The removal of the insulation 5 over the predetermined length 6 exposes a portion of the first metal 2 of the conductor 1.

[0027] The exposed area may also be referred to as a release area 7 .

[0028] Figure 3 shows the conductor 1 of Figures 1 and 2 after it has been placed into a mold 8. In this case, the mold 8 includes a lower portion 9 and an upper portion 10. The mold 8 serves the purpose of forming a bead in the stripped region 7 of the conductor 1 by moving the upper portion 10 of the mold 8 towards the lower portion 9.

[0029] 4 shows the conductor 1 after the upper portion 10 of the mold 8 has been moved towards the lower portion 9 of the mold 8, forming a bead 11 on the conductor 1. This may be done, for example, by forcing the upper portion 10 against the lower portion 9. In one exemplary embodiment, the formation of the bead 11 is done by drop forging, in which case the mold 8 is a drop forging mold.

[0030] The bead 11 displaces the conductor 1 at the stripped region 7. In this case, the depth 12 of the bead 11 may approximately match the thickness 13 of the insulation 5. In an alternative exemplary embodiment (not shown), the depth 12 of the bead 11 does not match the thickness 13 of the insulation 5.

[0031] FIG. 5 shows the conductor 1 from FIG. 4 after removal from the mold 8. The conductor 1 is pressed by a pressing device 14 against a workpiece 3, which in this case comprises a second metal 4. In the welding area 15, the first metal 2 of the conductor 1 is welded to the second metal 4 of the workpiece 3 by means of laser radiation 16. The bead 11 has the effect that the force that the pressing device 14 has to apply to the conductor 1 is smaller than in the case of welding methods known from the prior art, since due to the bead 11 the first metal 2 of the conductor 1 is already located substantially in contact with the second metal 4 of the workpiece 3, i.e. substantially without forming a gap. This applies in particular to the welding area 15.

[0032] The conductor 1 and the workpiece 3 form a conductor 1 and workpiece 3 arrangement 21, where the conductor 1 comprises a first metal 2 and the workpiece 3 comprises a second metal 4. The conductor 1 and the workpiece 3 are welded at a weld area 15, where the conductor 1 is stripped of insulation and includes a bead 11.

[0033] In this case, similar to FIG. 4, the depth 12 of the bead 11 may approximately correspond to the thickness 13 of the insulation 5 outside the stripped region 7 of the conductor 1 .

[0034] Figure 6 is a plan view of the multi-core conductor 1. In the insulation 5, the three cores 17 are each stripped of their outer sheath, and the first metal 2 of the cores 17 is visible because the outer sheath has been stripped. In cross section, this may correspond to Figure 2, where the cores 17 are arranged one behind the other, so that only one is visible.

[0035] Figure 7 shows the conductor 1 of Figure 6 after beads 11 have been formed on each core 17. This can be done using a forming die 8, for example by drop forging, in a manner similar to that described in Figures 3 and 4.

[0036] FIG. 8 is a plan view of the conductor 1 of FIG. 7 after the conductor 1 has been placed on the workpiece 3. In a manner similar to FIG. 5, the conductor 1 can be pressed against the workpiece 3 by a pressing device (not shown). In this case, the workpiece 3 comprises three conductive areas 19, with each core 17 being assigned a conductive area 19. As in FIG. 5, the bead 11 of the core 17 allows the core 17 to be placed in contact with the conductive area 19. Each core 17 comprises a welding area 15, in which the conductor 1 or the core 17 of the conductor 1 is welded to the workpiece 3 or to the conductive area 19 of the workpiece 3 by means of laser radiation 16 in a manner similar to FIG. 5. Furthermore, the cores 17 each comprise a further welding area 18, which is arranged in a similar manner in the region of the bead 11 in the peeling area 7, in which the core 17 can be welded to the conductive area 19 in a similar manner.

[0037] It is likewise conceivable to further weld the conductor 1 of FIG. 5 to the workpiece 3 in a further weld area 18 .

[0038] Here too, the conductor 1 and the workpiece 3 form an arrangement 21 of the conductor 1 in the workpiece 3, in which arrangement 21 the conductor 1 is welded to the workpiece 3. In particular, each core 17 of the conductor 1 is welded to a conductive area 19 of the workpiece 3. If the conductive areas 19 of the workpiece 3 are insulated from one another, various contacts of a battery, for example, can be provided.

[0039] FIG. 9 is a cross-sectional view showing a state in which a further conductor 1 is pressed against the workpiece 3 by a pressing device 14. In comparison with FIG. 5, the conductor 1 in FIG. 9 is pressed against the workpiece 3 by the pressing device 14 in the area of ​​the insulation 5, i.e. outside the stripping area 7 or bead 11. This is possible in particular whenever the depth 12 of the bead 11 corresponds to the thickness 13 of the insulation 5, as described above. Since mechanical contact between the first metal 2 of the conductor 1 and the second metal 4 of the workpiece 3 is still possible. The first metal 2 of the conductor 1 can therefore be welded to the second metal 4 of the workpiece 3 in the welding area 15 by means of laser radiation 16. For example, as shown in FIGS. 6 to 8, several cores 17 can be provided, each of which can be welded by this process to a corresponding conductive area 19 of the workpiece 3.

[0040] In a further weld region 18, the bead 11 is configured such that there is a distance 20 between the first metal 2 of the conductor 1 and the second metal 4 of the workpiece 3. During exposure to the laser radiation 16, as the first metal 2 is heated by the laser radiation 16, the first metal 2 expands.

[0041] Figure 10 shows the conductor 1 and workpiece 3 of Figure 9 after the first metal 2 has been welded to the second metal 4 in the weld region 15 and after the first metal 2 has expanded due to laser radiation 16 acting on the first metal 2. The expansion has the effect that the first metal 2 of the conductor 1 is then also positioned in contact with the workpiece 3 in a further weld region 18 and can there also be welded to the workpiece 3 by laser radiation 16. As before, the conductor 1 and the workpiece 3 again form an arrangement 21.

[0042] The conductor 1 may comprise a flat conductor having a rectangular cross section. In particular, the core 17 may be a flat conductor having a rectangular cross section, which improves the contact of the conductor 1 or the core 17 with the workpiece 3.

[0043] In Fig. 5 it is shown how the conductor 1 is pressed by the pressing device 14 in the stripping region 7 of the bead 11. In Figs. 9 and 10 the pressing device 14 is arranged in such a way that pressing takes place against the insulation 5. A combination is also conceivable, with one pressing device 14 pressing the conductor 1 in the region of the bead 11 or the stripping region 7 and the other pressing device 14 pressing the conductor 1 in the region of the insulation 5. Furthermore, or alternatively, it is also conceivable to provide fewer or more pressing devices 14, for example only one pressing device or three pressing devices. Instead of the pressing device 14, an air flow can also be used, by which the conductor 1 is pressed against the workpiece 3.

[0044] The first metal 2 can be welded to the second metal 4 in the weld area 15 or in the further weld area 18 by several weld points, i.e. by multiple exposure to the laser radiation 16 in each case. The weld points can be arranged, for example, in the form of a cross or a spiral. In this case, the laser radiation 16 can be laser radiation suitable for welding the first metal 2 and the second metal 4 together.

[0045] The cross section of the first metal 2 of the conductor 1 and the core 17 of the conductor 1 may in this case be 1 mm by 0.2 mm. This means that in figures 1 to 5 or 9 and 10 the first metal 2 is shown with a thickness of 0.2 mm, while the core 17 in figures 6 to 8 is shown with a width of 1 mm.

[0046] The thickness 13 of the insulator 5 may be between 0.1 and 0.5 mm, for example 0.3 mm. The depth 12 of the bead 11 may likewise be within this range, for example 0.3 mm.

[0047] The first metal 2 can include, be, or be a laser-weldable alloy of the aforementioned metals. The second metal 4 can include aluminum or a laser-weldable alloy that includes aluminum.

[0048] Although the invention has been explained and illustrated in more detail using preferred exemplary embodiments, the invention is not limited to the disclosed exemplary embodiments. Other variations can be derived from the exemplary embodiments and the description of the invention without departing from the scope of protection of the invention.

Claims

1. A method for welding a conductor (1) comprising a first metal (2) to a workpiece (3) comprising a second metal (4), comprising: removing a predetermined length (6) of insulation (5) of the conductor (1); forming a bead (11) in the stripped region (7) of the conductor (1) using a mold (8); - pressing the conductor (1) against the workpiece (3) by means of a pressing device (14) or an air current, resulting in mechanical contact in a welding area (15) between the conductor (1) and the workpiece (3), located in the area of ​​the bead (11); - laser welding the conductor (1) to the workpiece (3) in the welding area (15); The method includes:

2. The workpiece (3) comprises several conductive areas (19), The conductor (1) is part of a multi-core conductor (1), The insulation (5) is removed from all the cores (17) of the multi-core conductor (1), beads are formed on all the cores (17) of the multi-core conductor (1), all the cores (17) are pressed together, and the cores (17) are welded to their respective conductive regions (19). The method of claim 1.

3. After the laser welding, the conductor (1) is welded to the workpiece (3) by laser welding in a further weld area (18). The method according to claim 1 or 2.

4. the step of forming the bead is performed such that the conductor (1) is initially positioned in contact with the weld area (15) and not in contact with the further weld area (18); 4. The method according to claim 3, wherein thermal expansion during the laser welding in the weld area (15) has the effect that the conductor (1) deforms so that it then lies in contact with the further weld area (18).

5. The depth of the bead approximately corresponds to the thickness (13) of the insulator (5).

5. The method according to any one of claims 1 to 4.

6. The conductor (1) is a flat conductor having a rectangular cross section.

6. The method according to any one of claims 1 to 5.

7. The pressing step is performed in the stripped area (7) of the conductor (1), 7. The method according to any one of claims 1 to 6.

8. the pressing step is performed outside the stripped area (7) of the conductor (1); 7. The method according to any one of claims 1 to 6.

9. The step of laser welding in the welding area (15) is carried out by several welding points.

9. The method according to any one of claims 1 to 8.

10. The step of forming the bead is performed by drop forging.

10. The method according to any one of claims 1 to 9.

11. The pressing step is performed both in the stripped region (7) of the conductor (1) and outside the stripped region (7) of the conductor (1).

6. The method according to any one of claims 1 to 5.

12. The molding tool (8) includes at least two dies (9, 10). The method according to claim 1 or 10.

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