WO2025082558A1 - Method for connecting metal circuit boards by means of high-energy radiation - Google Patents

Abstract

The invention relates to a method for connecting metal circuit boards by means of high-energy radiation, wherein band-like carrier strips or separate flat components, as individual plates, are aligned with one another and brought together, are moved in a production line, are pressed against one another using a roller pair and are connected to one another with the aid of high-energy radiation. The problem addressed by the invention is that of providing such a method for producing circuit boards for bipolar plates, heat exchangers and similar technical objects which in particular significantly reduces the space required by related systems and/or permits optimum adaptation to the existing environment of the production line. This problem is solved in that the connection process is carried out in at least two separate process steps, which are carried out one after the other and in at least two different main processing directions, wherein in each process step with at least one processing stage, a group of weld seams is created by means of at least one roller pair and high-energy radiation allocated to said roller pair.

Description

Method for joining metallic circuit boards using high-energy radiation

The invention relates to a method for joining metallic circuit boards by means of high-energy radiation, wherein band-shaped carrier strips or separate flat components are aligned and brought together as individual plates, moved in a production line, pressed together with a pair of rollers and joined together by means of high-energy radiation.

Various technical objects consist of at least two metal plates joined together to form a flat base body. They have contours that form cavities between the facing inner surfaces of the metal plates, which are functionally relevant to the respective technical object. Typical objects in this regard include heat exchangers and bipolar plates for fuel cells.

DE 43 33 904 A discloses a heat exchanger for two flowing media with parallel flow channels. This heat exchanger consists of metal plates stacked on top of each other in layers, each with a profile to form a flow channel. Each plate lying on top covers the flow channels of the plate below.

According to DE 10 2019 202 493 A1, bipolar plates are manufactured by progressively feeding two separate plate strands in strip form from two spaced-apart devices onto one another in a feed process, pressing them together by rollers and joining them together in the effective area of the rollers.

Regardless of the specific design, the metal plates for the heat exchangers or bipolar plates are preferably joined together by means of high-energy radiation, in particular by electron beam or laser welding.

DE 102 43 833 A1 relates to a solution for laser welding thin components. Rollers are used as transport and clamping elements, exerting contact pressure on the components. The components are guided between the rollers and conveyed away from them by rotating the rollers, enabling continuous production. One roller is transparent so that a laser beam can be guided through it. This laser beam is focused on the workpiece and creates a welded joint.

1

Confirmation copy EP 4 046 739 A1 describes a method for laser welding metallic blanks. Starting with a band-shaped carrier strip in which a positioning and feed geometry is configured on each of its longitudinal sides and in which the contours of separate assemblies are completely formed, two carrier strips configured in this way are aligned with each other using the positioning and feed geometry to ensure identical contours, brought together by a transport system that engages the positioning and feed geometry, displaced longitudinally in a production line by the transport system, pressed together with a pair of rollers, and welded together with a laser beam.

Despite existing solutions for manufacturing printed circuit boards for heat exchangers and bipolar plates, there is still a significant need for development. The existing solutions require relatively long cycle times and considerable space requirements.

The object of the invention is to provide a method for manufacturing metallic blanks for bipolar plates, heat exchangers and similar technical objects using high-energy radiation, which method in particular significantly reduces the space requirements of such systems and/or enables optimal adaptation to the existing environment of the production line.

This object is achieved by carrying out the joining process in at least two separate process steps which are carried out consecutively in time and in at least two different main processing directions, whereby in each process step a group of weld seams is produced with at least one processing stage with at least one pair of rollers and with a high-energy radiation assigned to this pair of rollers.

In principle, the electron beam welding method can be used for this purpose. A preferred embodiment alternatively provides for the metallic blanks to be welded together using a laser beam. The laser welding process is carried out in at least two separate process steps, which are carried out sequentially and in at least two different main processing directions. In each process step, a group of weld seams is created with at least one processing stage using at least one pair of rollers and lasers assigned to this pair of rollers. One embodiment provides that at least a first process step is carried out in a first main processing direction and at least a second process step is carried out in a second main processing direction.

One embodiment provides that the second main machining direction is arranged at an angle relative to the first main machining direction, wherein this angle preferably has a maximum size of 90°.

A further embodiment provides that the first and second main processing directions are each related to the arrangement of a production line.

A further embodiment provides that the first and second main processing directions are each related to the arrangement of a board.

The features described above create a technical solution that enables the production of large quantities of metallic blanks for bipolar plates in fuel cells, for heat exchanger blanks, and similar technical objects using high-energy radiation. This significantly reduces the space requirements of such systems and enables largely optimal adaptation to the existing environment of the production line.

In the following, embodiments of the invention are explained with reference to the drawing.

The technical solution according to the invention is – as explained above – suitable for the production of various technical objects. An application for the production of bipolar plates for fuel cells is described below, using laser welding as an example of high-energy radiation. Such fuel cells are suitable for road and rail vehicles in which conventional combustion engines are replaced by other drive concepts. The figures show:

Fig. 1 shows a first embodiment of a device for carrying out the method

Fig. 2 a second embodiment of a device for carrying out the method

Fig. 3 a third embodiment of a device for carrying out the method

Fig. 4 a fourth embodiment of a device for carrying out the method The production lines shown stylized in the drawing are designed to carry out a method according to the invention for laser welding metallic blanks.

According to Fig. 1, the starting point for production is at least two initially separate and superimposed band-shaped carrier strips 1, in which a positioning and feed geometry 2 is preferably configured on both longitudinal sides. In the carrier strip 1, the contours of each separate component are completely formed by stamping, roll stamping, or similar processes, for example the mutually congruent contours of an anode or cathode of a bipolar plate.

At least one first processing stage 1-1 with at least one first pair of rollers W1 and W2 is arranged along the production line. Several lasers are assigned to the roller pair W1 and W2, for example, six lasers each. The specific number of lasers is determined taking into account the arrangement, length, and number of weld seams to be formed. A first group of weld seams is created at processing stage 1-1.

In the embodiment shown in Fig. 1, a second processing stage 1-2 with at least a second roller pair W3 and W4 is optionally provided. Several lasers are assigned to the roller pair W3 and W4, for example, also six lasers each. A second group of weld seams is created at this processing stage 1-2.

After passing through processing stages 1-1 and 1-2 in a first main processing direction, the band-shaped carrier strip 1 is separated into separate assemblies with a separating cut. These assemblies are subsequently transported and further processed in a second main processing direction.

In the embodiment shown in Fig. 1, the now separated assemblies are further processed in a second main processing direction that is spatially similar but arranged at a right angle to the first main processing direction, rotated by 90°. The basic orientation of the two main processing directions is stylized with an arrow each.

It is expressly pointed out that the selected change of direction by an angle of 90° is only given as an example. Other angles are also possible, whereby the specific value depends in particular on spatial conditions (e.g., dimensions of a production hall, etc.). The angle for the change of direction has a maximum size of 90° and can be determined in relation to the first main machining direction. can be aligned either to the left or to the right. Thus, the second main machining direction can be positioned within a total range of 180° relative to the first main machining direction.

At least one additional processing stage, specifically a third one in this case, 2-1, is now arranged along the production line, with at least one additional roller pair W5 and W6. Several lasers are assigned to the roller pair W5 and W6, for example, six lasers each. The specific number of lasers is also determined here, taking into account the arrangement, length, and number of weld seams to be formed. A third group of weld seams is created at processing stage 2-1.

In the embodiment shown in Fig. 1, a fourth processing stage 2-2 with at least one additional roller pair W7 and W8 is optionally provided. Several lasers are assigned to the roller pair W7 and W8, for example, also six lasers each. A fourth and final group of weld seams is created at this processing stage 2-2, so that the bipolar plate is completed after passing through this processing stage 2-2.

In the embodiment shown in Fig. 2, a largely identical process sequence is initially implemented up to the separation cut into separate assemblies.

After passing through processing stage 1-2, the band-shaped carrier strip 1 is cut into separate assemblies, which are then transported and further processed in a second main processing direction.

In contrast to Fig. 1, however, the now separated assemblies are not further processed in a spatially identical orientation. Instead, they are rotated by 90°. Thus, although the second main processing direction follows the same contour as the first main processing direction, the main processing directions are offset by 90° from each other in this variant, based on the relative position of the production line and the assembly.

Along the production line there is now at least one processing stage 2-1 and optionally another processing stage 2-2 with additional roller pairs W5 and W6 or W7 and W8 as well as several associated lasers.

The design shown in Fig. 3 basically corresponds to the process sequence according to

Fig. 1. However, no band-shaped carrier strips are used as the starting point of the Production is not used, but rather individual segments 3 as individual plates. These segments 3 also preferably have a positioning and feed geometry 2 on their long sides.

At least one first processing stage 1-1 with at least one first pair of rollers W1 and W2 is arranged along the production line. Several lasers are assigned to the roller pair W1 and W2, for example, six lasers each. The specific number of lasers is determined taking into account the arrangement, length, and number of weld seams to be formed. A first group of weld seams is created at processing stage 1-1.

In the embodiment shown in Fig. 3, the second processing stage 1-2 with at least a second roller pair W3 and W4 is also optionally provided. Several lasers are assigned to the roller pair W3 and W4, for example, again six lasers each. A second group of weld seams is created at this processing stage 1-2.

In the design according to Fig. 3, the otherwise necessary separating cut is omitted after passing through processing stage 1-1 and processing stage 1-2.

The already separate assemblies are now further processed in a second main machining direction that is spatially similar but arranged at a right angle to the first main machining direction, rotated by 90°. The basic orientation of the two main machining directions is stylized with an arrow. Here, too, the selected 90° change in direction is only an example. Other angles are also possible.

At least one additional processing stage, specifically a third one in this case, 2-1, is now arranged along the production line, with at least one additional roller pair W5 and W6. Several lasers are assigned to the roller pair W5 and W6, for example, six lasers each. The specific number of lasers is also determined here, taking into account the arrangement, length, and number of weld seams to be formed. A third group of weld seams is created at processing stage 2-1.

In the embodiment shown in Fig. 3, a fourth processing stage 2-2 with at least one additional roller pair W7 and W8 is optionally provided. Several lasers are assigned to the roller pair W7 and W8, for example, also six lasers each. A fourth and final group of weld seams is created at this processing stage 2-2, so that the bipolar plate is completed after passing through this processing stage 2-2. In the embodiment according to Fig. 4, an identical process sequence is initially implemented as in the variant according to Fig. 3.

In contrast, after completing processing stages 1-2, the assemblies are not further processed in a spatially consistent orientation. Instead, they are rotated by 90°. Thus, although the second main processing direction follows the same contour as the first main processing direction, the main processing directions are offset by 90° from each other in this variant, based on the relative position of the production line and the assembly.

At least one processing stage 2-1 and optionally another processing stage 2-2 with additional roller pairs W5 and W6 or W7 and W8 as well as several associated lasers are now arranged along the production line.

Claims

Patent claims 1 . A method for joining metallic blanks by means of high-energy radiation, wherein band-shaped carrier strips or separate flat components are aligned with one another and brought together as individual plates, moved in a production line, pressed against one another with a pair of rollers and joined together with the aid of high-energy radiation, characterized in that the joining process is carried out in at least two separate process steps which are carried out successively in time and in at least two different main processing directions, wherein in each process step with at least one processing stage with at least one pair of rollers and with high-energy radiation assigned to this pair of rollers a group of weld seams is produced. 2. Method according to claim 1, characterized in that the metallic blanks are welded together with a laser beam, wherein the laser welding process is carried out in at least two separate process steps which are carried out successively in time and in at least two different main processing directions, wherein in each process step with at least one processing stage with at least one pair of rollers and with lasers assigned to this pair of rollers a group of weld seams is produced. 3. Method according to claim 1, characterized in that at least a first process step is carried out in a first main processing direction and at least a second process step is carried out in a second main processing direction. 4. Method according to claim 1, characterized in that the second main machining direction is arranged at an angle to the first main machining direction. 5. The method according to claim 4, characterized in that the angle between the first main machining direction and the second main machining direction has a maximum size of 90°. 6. Method according to claim 1, characterized in that that the first and second main machining directions are each related to the arrangement of a production line. 7. The method according to claim 1, characterized in that the first and second main processing directions are each related to the arrangement of a circuit board.