Method for connecting a cable to a printed circuit board

Abstract

The invention relates to a method for connecting a cable (12), in particular a multi-strand cable, to a printed circuit board (1), wherein a connection point (4a) for the cable (12) is formed on the printed circuit board (1), and wherein a plurality of components (6) are attached to a surface of the printed circuit board (1) in a SMT process, characterized in that an intermediate element (7) is also attached to the printed circuit board (1) as part of the SMT process, wherein an electrical contact is established between the intermediate element (7) and the connection point (4a), and that the cable (12) is attached to the intermediate element (7) by laser welding. The invention simplifies the connection of cables to printed circuit boards.

Description

The invention relates to a method for connecting a cable, in particular a multi-stranded cable, to a printed circuit board, wherein a connection point for the cable is formed on the printed circuit board, and wherein a plurality of components are fastened on a surface of the printed circuit board in an SMT process.Printed circuit boards (also referred to as PCBs) are used in various branches of the art to interconnect electrical components. The printed circuit boards have conductor structures with which current paths are provided, by means of which components arranged on the printed circuit board or their connections are electrically connected to one another. The components are usually fastened to the printed circuit board by means of a so-called SMT process (SMT=surface mounted technology).The printed circuit boards additionally provide connection points to which cables can be connected (connected) which electrically connect the printed circuit board to further electrical devices (for example further printed circuit boards, power sources, electric motors, antennas or other user devices).Usually, such cables, which are usually designed as multi-stranded cables, are soldered onto the connection points.For soldering on, a terminal end of the cable must be positioned on the terminal location, a soldering tin must be supplied, and the soldering tin must be melted, for example with a soldering tip of a soldering iron. This procedure is comparatively difficult and complicated, and in particular difficult to automate, and therefore usually takes place manually. This limits the throughput in production and also makes production expensive.Object of the InventionIt is the object of the invention to provide a method with which the connection of cables to printed circuit boards can be simplified.DESCRIPTION OF THE INVENTIONThis object is achieved according to the invention by a method of the type mentioned at the beginning, which is characterized in that, within the scope of the SMT process, an intermediate element is also fastened on the printed circuit board, wherein an electrical contact is established between the intermediate element and the connection point, and in that the cable is fastened on the intermediate element by laser welding.The method according to the invention provides for, within the scope of the SMT process which takes place anyway for a multiplicity of components which are intended to be arranged on the printed circuit board, also fastening intermediate elements on the printed circuit board, which intermediate elements can be used for connecting the cables. The intermediate elements are soldered onto the printed circuit board in a manner known per se within the scope of the SMT process. For this purpose, solder paste is initially applied locally to the printed circuit board in the region of the respective connection point of the intermediate element, typically printed; in the context of this printing process, solder paste is also locally printed for the further components in the region of their connection points. The respective intermediate element is then positioned on the printed circuit board, for example rolled off from a reel, and the further components are also positioned on the printed circuit board. Heating then takes place, typically in an oven, whereby the tin in the solder paste is melted, so that the intermediate element is soldered onto the printed circuit board. The same applies to the further components. The SMT process is typically fully automated within the scope of the invention, also with respect to the intermediate element or elements.The cable is then welded onto the intermediate element by laser welding. The intermediate element can be selected with regard to material and geometry such that it is suitable as a basis for the intended welding process, and in particular the printed circuit board lying beneath it is not damaged and any heating of a tin layer lying beneath the intermediate element is sufficiently small so that the intermediate element remains fastened on the printed circuit board during laser welding. For this purpose, the intermediate element can ensure in particular a sufficient heat dissipation from the welding zone, for example by a sufficient inherent size (heat capacity) and / or sufficient inherent thermal conductivity and / or a connection of good thermal conductivity to non-heat-sensitive masses. The printed circuit board, on the other hand, generally does not need to be particularly viable for the welding process.Laser welding allows very rapid heating of the material to be welded of the cable (i.e. of its electrically conductive wire) and / or of the material of the intermediate element to the melting point or above, and generally does not require the supply of additional materials. The connection between the cable and the intermediate element can be produced correspondingly easily and quickly, in particular much easier and faster than in a soldering process. The laser beam can be aligned and guided by means of a scanner (for example with a mirror which can be pivoted via piezoelectric elements), so that zones of the cable and / or of the intermediate element to be melted can be sought and traversed in a targeted manner in a simple manner using the laser beam. The laser beam is typically directed substantially perpendicularly to the upper side of the intermediate element (e.g. at an angle of 90° + / - 20° to the upper side of the intermediate element).An automation of the laser welding provided according to the invention is possible in a comparatively simple manner, and accordingly the respective fastening of the cable on the intermediate element is typically fully automated within the scope of the invention. Accordingly, a high throughput in production can be achieved within the scope of the invention.The cable is generally welded on a welding surface (land) of the intermediate member, which is typically formed on an upper surface of the intermediate member that is opposite to the circuit board. The welding surface is then particularly easily accessible for laser welding. The welding surface can be planar in the simplest case; however, the welding surface can also be contoured, for example with a depression or groove, into which a connection end (conductor end) of the cable can be inserted or pressed.In addition, it is noted that a very high mechanical strength of the connection of the cable (or its core) to the printed circuit board can also be achieved by means of laser welding. The welded connection of the cable to the intermediate element may in particular also be loaded under tension, in contrast to a soldered connection of the cable.A typical intermediate element is substantially cuboidal, having a width of 0.5 mm to 1.5 mm, preferably 0.8 mm to 1.2 mm, furthermore a length of 1.75 cm to 4.25 cm, preferably 2.5 mm to 3.5 mm, and furthermore a height (also referred to as thickness) of 0.3 mm to 0.8 mm, preferably 0.4 mm to 0.6 mm, and made of elemental copper. In the case of larger cross sections of the cable, the intermediate element can also be formed to be wider, longer and / or higher, for example with a width of up to 2.5 mm and / or a length of up to 6 cm and / or a height of up to 1.5 mm, or even more.The cable (also called connecting cable) typically has a conductive core surrounded by an insulating jacket, usually made of plastic, wherein the conductive core is usually formed by one strand or a plurality of strands (in the latter case, the cable is also referred to as "multi-strand cable"). Multi-stranded cables in which the strand is formed by a plurality of strands twisted together or braided together are preferred for the invention. In the region of a connection end, in which region the welding to the intermediate element also takes place, the insulating jacket is removed. The (stripped) terminal end of a cable to be fastened (in other words the core) typically has a diameter of 0.3 mm to 0.8 mm, preferably 0.4 mm to 0.6 mm. However, larger diameters, for example up to 1.5 mm, or even larger, are also possible. The conductive lead of the cable is typically made of elemental copper.Preferred Variations of the InventionIn a preferred variant of the method according to the invention, during laser welding, the cable is pressed onto the intermediate element, in particular in the region of a connection end of the cable, by means of a holding-down device. By pressing with the hold-down device, an electrical wire to be welded, in particular comprising a plurality of strands to be welded, of the cable can be compacted. A rapid production of a mechanically stable welded connection between the cable (or the core) and the intermediate element is facilitated.A further development of this variant is preferred, in which the holding-down device is designed as a mask which shades the printed circuit board at least largely for spatter, wherein the mask has a recess through which a laser beam is directed onto a connection end of the cable and / or onto the intermediate element in a vicinity of the connection end during the laser welding. The holding-down device designed as a mask makes it possible to protect the remaining printed circuit board from spatter, while the cable is welded on the intermediate element with a laser beam running through the recess. In particular, damage to further electronic components due to hot metal or short circuits at their connections can be avoided. The recess makes the zone to be welded easily accessible to the laser beam. The recess can be funnel-shaped (narrowing towards the intermediate element) in order to improve the accessibility of the welding zone for an obliquely incident laser beam and at the same time also to ensure good covering of the printed circuit board. In the simplest case, the mask can easily cover the printed circuit board, typically with mask sections which run parallel to the printed circuit board above the printed circuit board. However, it is also possible to provide the mask with collar portions which project away from the printed circuit board in a direction with which obliquely flying spatters can be blocked. It should be noted that the mask must cause shading of only a vicinity of the recess in which spatter still occurs.A variant is advantageous in which the intermediate element is selected from copper as intermediate element. Copper is easy to weld, has good electrical conductivity, and is comparatively cost-effective. An intermediate element is considered in the context of the invention to be an intermediate element made of copper if it consists of at least 75% by weight, preferably at least 90% by weight, particularly preferably at least 99% by weight, of copper. Typically, the intermediate element is made of elemental copper. Alternatively, an intermediate element can also be manufactured, for example, as an intermediate element from aluminum (with 75 wt % aluminum or more) or as an intermediate element from silver (with 75 wt % silver or more) or as an intermediate element from steel.A variant is likewise advantageous in which the cable is selected as a cable with a core of copper. Copper is easy to weld, has good electrical conductivity, and is comparatively cost-effective. A conductor is considered in the context of the invention to be a conductor made of copper if it consists of at least 75% by weight, preferably at least 90% by weight, particularly preferably at least 99% by weight, of copper. Typically, the core is made of elemental copper (typically wherein a core comprises multiple strands). Alternatively, the wires can also be selected, for example, as wires made of steel (typically wherein one wire comprises a plurality of strands).Particularly preferred is a variant in which a wavelength of a laser beam used in laser welding is selected such that an absorption of the laser beam in the material of the intermediate element and / or in the material of the core of the cable is higher by a factor FKT than in a tin layer with which the intermediate element is fastened to the printed circuit board in the course of the SMT process, with FKT≥5, preferably FKT≥10. If the tin layer lying under the intermediate element is reached (exposed) during laser welding, the introduction of laser energy into the tin layer is only slight, and direct heating of the tin layer by the laser beam is reduced. Accordingly, softening of the tin layer and thus loosening of the fastening of the intermediate element on the printed circuit board can be minimized.A preferred development of the above variant provides that the intermediate element is made of copper, that the cable with a core is made of copper, and that the laser beam with a wavelength in a range from 400 nm to 650 nm is selected, in particular wherein the laser beam is generated with a blue or green diode laser. By selecting copper for the intermediate element and the core of the cable and selecting the laser wavelength from 400 nm to 650 nm, a high absorption of laser energy in the material of the intermediate element and in the material of the core on the one hand, and a low absorption of laser energy in a tin layer situated below the intermediate element, corresponding to a factor FKT of 10 or more, can be easily set. In addition, both copper and laser sources in the wavelength range 400 nm to 650 nm are available at low cost. Diode lasers allow very particularly cost-effective operation.A variant is preferred in which a laser beam is guided with a scanner optics during laser welding. As a result, it is possible in a simple and cost-effective manner to direct the laser beam onto the cable (or its core) and the intermediate element and to guide it according to a desired welding path, for example along the edges (in a plan view from above) of the cable (or the core). The scanner optics can in particular comprise a mirror pivotable by means of piezoelectric elements.In an advantageous variant, the intermediate element is selected to have a thickness of at least 300 μm, preferably at least 400 μm. With a thickness of at least 300 μm, the cable can generally be welded onto the intermediate element without significantly softening the tin layer lying under the intermediate element or even exposing the tin layer during welding. Thicker intermediate elements can achieve a greater degree of safety and further reduce the heat input into the tin layer. Particularly preferred are thicknesses of the intermediate element in the range 400 μm to 600 μm; in the case of larger cable cross sections, larger thicknesses of the intermediate element, for example up to 1.5 mm, or even more, are also used.A variant is also preferred in which the intermediate element is selected to be substantially cuboidal. The cuboid shape is simple to produce and easy to handle, in particular when positioning the intermediate element during the SMT process. Usually, the intermediate element is elongated in a direction along which a terminal end of the cable is also positioned on the intermediate element.In a preferred variant, it is provided that the intermediate element has a depression, into which a connection end of the cable is inserted for laser welding. The depression facilitates the positioning of the cable or its connection end on the intermediate element. The depression can also achieve a greater contact surface of the cable or of the exposed core on the intermediate element, which can improve the mechanical connection by means of laser welding.Circuit Board Subassembly (Intermediate Product) According to the InventionThe scope of the present invention also includes a printed circuit board subassembly comprisinga printed circuit board, anda plurality of components which are fastened on the printed circuit board by an SMT process, The device is characterized in that the components comprise at least one intermediate element which is fastened to the printed circuit board by the SMT process, such that an electrical contact is established between the intermediate element and a connection point of the printed circuit board, and in that the intermediate element has a welding surface which is suitable for fastening a cable by laser welding, in particular wherein the welding surface is formed on an upper side of the intermediate element facing away from the printed circuit board. Starting from this printed circuit board sub-arrangement to be produced in a simple manner (in particular automatically), a cable can be fastened and electrically connected to the intermediate element or its welding surface in a simple manner (in particular automatically) by laser welding. Within the scope of the SMT process for fastening components, which is to be provided in any case, the additional fastening of the intermediate element or elements does not cause any appreciable additional outlay.Circuit Board Arrangement According to the InventionAlso within the scope of the present invention is a printed circuit board arrangement comprisinga printed circuit board,a plurality of components which are fastened on the printed circuit board by an SMT process, andat least one cable which is connected to the printed circuit board, A device according to the invention, characterized in that the components comprise at least one intermediate element which is fastened to the printed circuit board by the SMT process, such that an electrical contact is established between the intermediate element and a connection point of the printed circuit board, and in that the at least one cable is fastened to the at least one intermediate element by laser welding. This printed circuit board arrangement can be produced in a simple manner (in particular in an automated manner). In particular, the production of the printed circuit board arrangement can be effected cost-effectively and with a high throughput. The cable (or its conductive wire) can be fastened in particular to a welding surface of the intermediate element, which is formed on an upper side of the intermediate element facing away from the printed circuit board. Printed circuit board arrangements according to the invention can be used, for example, for the control of electric motors or for the control of the charging and discharging of batteries of electric vehicles.An embodiment of the circuit board arrangement according to the invention which is produced by a method according to the invention described above is preferred.Production Station According to the InventionFinally, the scope of the invention also includes a manufacturing station configured for the automatic manufacture of circuit board arrangements according to the invention described above in a method according to the invention described above. The manufacturing station typically comprises an automated SMT process station and an automated laser welding station, preferably wherein these are linked to one another by an automated transport system. With the manufacturing station, the printed circuit board arrangements can be produced cost-effectively and with high throughput.Further advantages of the invention will become apparent from the description and the drawing. Likewise, the features mentioned above and those set out further below can be used according to the invention individually or together in any desired combinations. The embodiments shown and described are not to be understood as a final enumeration, but rather have exemplary character for describing the invention.DETAILED DESCRIPTION OF THE INVENTION AND DRAWINGFIG. 1 aschematically illustrates the manufacture of an exemplary embodiment of a printed circuit board arrangement according to the invention within the scope of an exemplary variant of the method according to the invention, at the beginning of the manufacture; FIG. 1 b illustrates the production of FIG. 1 a, after application of solder paste; FIG. 1 c illustrates the production of FIG. 1 a, after positioning of the components; FIG. 1 dillustrates the production of FIG. 1 a, during heating; FIG. 1 eillustrates the fabrication of FIG. 1 aafter positioning the cable on the interposer; FIG. 1 fillustrates the production of FIG. 1 aafter the hold-down device has been placed on; FIG. 1 gillustrates the manufacture of FIG. 1 a, during laser welding; FIG. 1 hillustrates the fabrication of FIG. 1 a, at the end of fabrication; FIG. 2 shows a schematic perspective view of an exemplary intermediate element with a depression for inserting a terminal end of a cable, for the invention; FIG. 3 shows a schematic top view of a holding-down device, which is designed as a mask, for the invention; FIG. 4 illustrates a modification of the variant of FIGS. 1 a- 1 h, wherein a hold-down device in the form of a mask with a collar section is used.FIGS. 1 ato 1 hschematically illustrate the sequence of a method according to the invention for connecting a cable to a printed circuit board in an exemplary variant. The method produces a printed circuit board arrangement according to the invention, which is shown schematically in FIG. 1 hin an exemplary embodiment. FIGS. 1a to 1h each show cross sections through the printed circuit board arrangement (partly or completely manufactured).At the beginning of the method, cf. FIG. 1 a, a printed circuit board 1 is provided, which forms a multiplicity of conductor structures 2 which run on and in the printed circuit board 1 in order to electrically connect electrical components to be mounted on the printed circuit board 1 to one another. The conductor structures 2 are typically made of copper, and the remaining printed circuit board 1 is typically made of an electrically insulating plastic with fiber reinforcement, for example of so-called hard paper. On the upper side 3 of the printed circuit board 1, the conductor structures 2 form connection points 4 a, 4 b, 4 cto which electrical components are to be soldered in the course of an SMT process in order to establish an electrical contact. An intermediate element is to be fastened at the connection point 4 ain this case, and an electrolytic capacitor is to be fastened at the connection points 4 band 4 cin this case.As a first step of an SMT process, solder paste 5 is now applied locally on the surface 3 of the printed circuit board 1, namely on the connection points 4 a, 4 b, 4 c, corresponding to three solder paste fields 5 a, 5 b, 5 c, cf. FIG. 1 b. It should be noted that mostly the solder paste fields 5a-5c (in plan view) are slightly smaller than the connection pads 4a-4c or are as large as the latter. The solder paste 5 is applied (not shown in more detail), for example, by a printing method (preferably stencil printing).Subsequently, in a next step, the components 6 to be fastened, illustrated here, an intermediate element 7 and an electrolytic capacitor 8, are placed on the printed circuit board 1, cf. FIG. 1 c. As a rule, the solder paste 5 is sufficiently tacky so that the components 6, 7, 8 then adhere sufficiently to the printed circuit board 1 for the further method. When the components 6 are placed on, they can be rolled off a roll (not shown in detail), for example, or can be placed on with a robot gripping arm (likewise not shown in detail). The intermediate element 7 is formed here as a cuboid made of elemental copper, which here has a thickness D of 400 μm. The intermediate element 7 is placed essentially centrally on the solder paste field 5 aor centrally on the connection point 4 a. The electrolytic capacitor 8 here has two contact regions 9 a, 9 bwhich are placed on the solder paste fields 5 b, 5 c.In a next step, shown in FIG. 1 d, the solder paste fields 5 a- 5 care heated. In the example shown, this heating is set up in that the printed circuit board 1 runs through an oven in which the printed circuit board 1 is irradiated from above with infrared emitters 10. However, other methods of heating are also possible, for example using heating plates (not shown in detail). The heating causes the tin powder in the solder paste 5 to be melted and activates the flux likewise contained in the solder paste 5. An electrical contact is thereby established between the connection points 4 a, 4 b, 4 cand the intermediate element 7 or the contact regions 9 a, 9 bof the electrolytic capacitor 8 by soldering. The solder paste fields 5a-5c become tin layers 23, after this soldering, the SMT process is completed. The fastening of the intermediate element 7 can be integrated without problems into the SMT process, which is integrated for the remaining components 6 of the printed circuit board 1 (represented here by the electrolytic capacitor 8).The printed circuit board 1 with the components 6 fastened thereon, including fastened intermediate element 7, as obtained after the SMT process, is also referred to as a printed circuit board subassembly 20.Subsequently, a stripped connecting end 11 of a cable 12 to be welded on is arranged on a welding surface 13 of the intermediate element 7, cf. FIG. 1 e. The welding surface 13 is formed on an upper side of the intermediate element 7 which faces away from the printed circuit board 1. For positioning the cable 12, a robot arm (not shown in detail) can be used, for example. A core 16 of the cable 12 runs in an insulating jacket 16 a, which is removed in the region of the connection end 11. The core 16 of the cable 12 is here formed with a plurality of strands (not shown in detail), which are here produced from elemental copper.A holding-down device 14, which is designed here as a mask 15, is then lowered onto the printed circuit board 1, for example again using a robot arm (not shown in more detail). As a result, the connection end 11 of the cable 12 is pressed onto the intermediate element 7 or onto the welding surface 13, cf. FIG. 1 f. In the embodiment shown, the mask 15 covers the remaining printed circuit board 1 on the upper side 3 parallel thereto in order to protect the latter from spatter during the subsequent laser welding. It is also possible to provide the mask 15 at least partially with upwardly projecting collar sections as splash guard walls, and thus to protect the printed circuit board 1 from spatter (not shown in FIG. 1 f, but cf. FIG. 4 for this). A recess 15a is formed in the mask 15, through which a portion of the terminal end 11 of the cable 12 and a portion of the upper side of the intermediate element 7 are accessible. The recess 15 ais funnel-shaped here and narrows downward toward the printed circuit board 1. In the exemplary embodiment shown, the mask 15 presses onto the connection end 11 in front of and behind the recess 15 a; it is alternatively also possible to press down the connection end 11 only in front of or only behind the recess 15 a(not illustrated in more detail).Laser welding is now carried out. For this purpose, a laser beam 17 from a laser source 18 is directed by means of a scanner optics 19 through the recess 15a onto the connection end 11 of the cable 12 and the surface of the intermediate element 7 and guided in the desired manner, cf. FIG. 1g. The scanner optics 19 typically comprise at least one pivotable scanner mirror 19 aand a focusing lens 19 b. The material of the core 16 and the material of the intermediate element 7 are melted during laser welding, and a welded connection is produced between the intermediate element 7 and the terminal end 11 of the cable 12. The laser source 18 is selected here as a blue diode laser with a wavelength of the laser light in the laser beam 17 of approximately 450 nm. This wavelength has the advantage that the laser power is well absorbed in the copper of the strands 16 and in the copper of the intermediate element 7, but not in the tin of the tin layer 23 under the intermediate element 7 obtained after heating (FIG. 1 d).After the end of the laser welding, the hold-down 14 is removed from the printed circuit board 1 and a printed circuit board arrangement 21 is finished, as is illustrated in isolation in FIG. 1 h.FIG. 2 shows a schematic, perspective illustration of an exemplary intermediate element 7 for the invention, which is of substantially cuboidal design, and in the configuration shown has a depression 22 in its upper-side welding-on surface 13. This depression 22 is here substantially semi-cylindrical and extends along the long side of the intermediate element 7. a connection end 11 of a cable 12 to be fastened can be inserted into the depression 22 and pressed in, for example with a holding-down device (not shown in more detail, cf. FIG. 1 ffor placing a holding-down device).FIG. 3 schematically shows a top view of a holding-down device 14, which is designed as a mask 15, for the invention. Where the mask 15 in the state in which it is placed on the printed circuit board lies over the connection end of the cable and over the intermediate element, the recess 15 ais provided. The recess 15a is formed as a funnel-shaped hole; it can alternatively also be formed as a slot running inwards from the edge of the mask 15 (the latter not shown in more detail).FIG. 4 illustrates a modification of the variant shown in FIGS. 1 a- 1 h, cf. in particular the stage there of FIG. 1 f; only the essential differences are explained below. The one holding-down device 14 used in FIG. 4 is likewise designed as a mask 15, which here has, on its right-hand side in FIG. 4, a collar section 24, which projects obliquely upwards (away from the printed circuit board 1). On the left side, the mask 15 has a collar portion 25 that protrudes vertically upward. As a result, when the core 16 is welded to the intermediate element 7, spatters ejected upward are captured in the region of the recess 15 a, and the upper side 3 of the printed circuit board 1 is thus largely protected from spatters. In particular, the component 6 is also protected in the form of an electrolytic capacitor 8. When using inclined collar sections, the mask 15 can usually be made much more compact than in the case where the printed circuit board 1 is protected by overlapping parallel to the top side 3.List of reference characters1 Printed circuit board 2 Conductor structure 3 Upper side of the printed circuit board 4 a Anschluss point for intermediate element 4 b, 4 c Anschluss points for further component 5 Solder paste 5 a- 5 c Lötpaste paste fields 6 Component 7 Intermediate element 8 Electrolytic capacitor 9 a, 9 bContact regions 10 Infrared emitter 11 Terminal end 12 Cable 13 Welding surface 14 Hold-down device 15 Mask 15 a Ausnehmung 16 Lead 16 a Isolierender jacket 17 Laser beam 18 Laser source 19 Scanner optics 19 a Scanner mirror 19 bFocus lens 20 Printed circuit board subassembly 21 Printed circuit board assembly 22 Depression 23 Tin layers 24, 25 Collar portions of the mask D Thickness of the intermediate element

Claims

Method for connecting a cable (12), in particular a multi-stranded cable, to a printed circuit board (1), wherein a connection point (4a) for the cable (12) is formed on the printed circuit board (1), and wherein a plurality of components (6) are fastened on a surface of the printed circuit board (1) in an SMT process on the printed circuit board (1), characterized in that, within the scope of the SMT process, an intermediate element (7) is also fastened on the printed circuit board (1), wherein an electrical contact is established between the intermediate element (7) and the connection point (4a), and in that the cable (12) is fastened on the intermediate element (7) by laser welding.Method according to Claim 1, characterized in that during the laser welding the cable (12), in particular in the region of a connection end (11) of the cable (12), is pressed onto the intermediate element (7) by means of a holding-down device (14).Method according to Claim 2, characterized in that the holding-down device (14) is designed as a mask (15) which shades the printed circuit board (1) at least largely for spatter, wherein the mask (15) has a recess (15a), through which a laser beam (17) is directed onto a connection end (11) of the cable (12) and / or onto the intermediate element (7) in a vicinity of the connection end (11) during the laser welding.Method according to one of the preceding claims, characterized in that the intermediate element (7) is selected as an intermediate element (7) from copper.Method according to one of the preceding claims, characterized in that the cable (12) is selected as a cable (12) with a core (16) made of copper.Method according to one of the preceding claims, characterized in that a wavelength of a laser beam (17) used in laser welding is selected such that an absorption of the laser beam (17) in the material of the intermediate element (7) and / or in the material of a core (16) of the cable (12) is higher by a factor FKT than in a tin layer (23), with which the intermediate element (7) is fastened to the printed circuit board (1) within the scope of the SMT process, with FKT≥5, preferably FKT≥10.Method according to Claim 6, characterized in that the intermediate element (7) is produced from copper, in that the cable (12) with a core (16) is produced from copper, and in that the laser beam (17) is selected with a wavelength in a range from 400 nm to 650 nm, in particular wherein the laser beam (17) is generated with a blue or green diode laser.Method according to one of the preceding claims, characterized in that during the laser welding a laser beam (17) is guided by means of a scanner optical unit (19).Method according to one of the preceding claims, characterized in that the intermediate element (7) is selected with a thickness (D) of at least 300 μm, preferably at least 400 μm.Method according to one of the preceding claims, characterized in that the intermediate element (7) is selected to be substantially cuboidal.Method according to one of the preceding claims, characterized in that the intermediate element (7) has a depression (23), into which a connection end (11) of the cable (12) is inserted for laser welding.Printed circuit board sub-arrangement (20), comprising - a printed circuit board (1), and - a plurality of components (6) which are fastened on the printed circuit board (1) by an SMT process, characterized in that the components (6) comprise at least one intermediate element (7) which is fastened on the printed circuit board (7) by the SMT process, such that an electrical contact is established between the intermediate element (7) and a connection point (4a) of the printed circuit board (7), and in that the intermediate element (7) has a welding surface (13) which is suitable for fastening a cable (12) by laser welding, in particular wherein the welding surface (13) is formed on an upper side of the intermediate element (7) which is remote from the printed circuit board (1).Printed circuit board arrangement (21), comprising - a printed circuit board (1), - a plurality of components (6) which are fastened on the printed circuit board (1) by an SMT process, and - at least one cable (12) which is connected to the printed circuit board (1), characterized in that the components (6) comprise at least one intermediate element (7) which is fastened on the printed circuit board (1) by the SMT process, such that an electrical contact is established between the intermediate element (7) and a connection point (4a) of the printed circuit board (1), and in that the at least one cable (12) is fastened on the at least one intermediate element (7) by laser welding.Printed circuit board arrangement (21) according to Claim 13, produced by a method according to one of Claims 1 to 11.Manufacturing station, configured for the automatic manufacturing of printed circuit board arrangements (21) according to claim 13 in a method according to one of claims 1 to 11.

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