Assembly with a connecting element, inverter with an assembly

Abstract

Assembly (30), comprising, - at least one printed circuit board (20) with power semiconductor components arranged on it; - at least one busbar (10) for electrical contacting the printed circuit board (20), wherein - which is electrically and mechanically connected to at least one circuit board (20) and at least one busbar (10) by means of at least one connecting element (1) and at least one screw (12), and - which has at least one connecting element (1): - a first contact area (2) formed for connection with the printed circuit board (20), - a second contact area (4) designed for connection to the busbar (10) and - a resilient section (3) between the first contact area (2) and the second contact area (4), wherein the resilient section (3) is suitable to compensate for a tolerance of a distance between the first contact area (2) and the second contact area (4).

Description

[0001] The present invention relates to an assembly comprising a printed circuit board, a busbar, and a connecting element for establishing an electrical and mechanical connection between the printed circuit board and the busbar. The invention further relates to an inverter or a power inverter comprising at least one such assembly.

[0002] To connect a busbar to a printed circuit board (PCB), the PCBs are typically fitted with separate components in the form of metal sockets with threaded inserts, sometimes reinforced with plastic. Due to component-related tolerances, these tolerances can accumulate during installation. This includes, in particular, tolerances of the housing, PCB, sockets, and busbars.

[0003] This can cause the busbar to deform elastically and potentially plastically under tensile or compressive loads during screwing to the socket. This results in stresses in the busbar and the circuit board. The resulting deflections can reduce the service life of the components, especially the circuit board and the electronic components mounted on it. Stresses on the connection between the socket and the circuit board can lead to the socket detaching and loss of contact.

[0004] Additionally, thermal expansion of the components during operation and due to environmental influences can amplify this effect. This is particularly critical for extended components such as busbars.

[0005] Flexible busbars with copper braiding solve this problem, but are very expensive and have a higher failure rate. Busbars with S-shaped deflection often do not achieve the necessary maximum deflections to reliably ensure tolerance compensation across all operating points.

[0006] Document DE 10 2016 217 728 A1 discloses a carrier assembly, in particular for power electronics, comprising a carrier substrate with at least one electrically conductive planar conductor track with a top surface, wherein the carrier assembly further comprises at least one integrally formed electrically conductive connecting element for electrically contacting the carrier assembly with a busbar, wherein a base surface is formed on the connecting element with which the connecting element indirectly and / or directly abuts the top surface of the conductor track and is connected to it, wherein a contact surface for contacting the connecting element with the busbar is further formed on the connecting element.wherein the contact surface is spaced from the top of the conductor track in a perpendicular direction and is arranged substantially parallel to the top of the conductor track.

[0007] Document DE 10 2021 204 432 A1 discloses a connecting element of a battery module with a first connection area, which is configured to form an electrically conductive connection with an electrical circuit board of the battery module, and a second connection area, which is configured to form an electrically conductive connection with a voltage tap of the battery module, wherein a connecting area connects the first connection area and the second connection area to each other, which is further configured in such a way that a first plane in which the first connection area is arranged and a second plane in which the second connection area is arranged are spaced apart from each other in a vertical direction, wherein the first connection area and the second connection area are further arranged offset from each other in a longitudinal direction perpendicular to the vertical direction.

[0008] Document WO 2009 / 100 998 A2 discloses a compression spring contact made of a ribbon-like material arranged in a housing, with a contacting area for contacting a conductive element, in particular a conductor track or busbar, and a spring arm extending between an abutment, preferably in the housing, and the contacting area, wherein the spring arm is subdivided into at least two or more spring sections arranged vertically above the contact area via several bending areas and / or folds.

[0009] Document DE 10 2010 014 940 A1 discloses a power semiconductor module comprising at least one substrate, conductor tracks arranged according to the circuit, a housing, and at least one first and one second terminal element. Each terminal element has a first contact section, a second contact section, and a resilient section. For a compact arrangement and to prevent electromagnetic induction, the resilient section of the second terminal element is designed as a helical spring and at least partially surrounds the first terminal element.

[0010] It is therefore an object of the present invention to provide an assembly comprising a printed circuit board, a busbar, and a connecting element for establishing an electrical and mechanical connection between the printed circuit board and the busbar, which enables tolerance compensation in a technically simple manner and can be used with existing busbars and printed circuit boards. The connection should be durable and robust and suitable for both stationary applications and, for example, in the automotive sector.

[0011] A connecting element for establishing an electrical and mechanical connection between a printed circuit board and a busbar is described, comprising a first contact area configured for connection to the printed circuit board and a second contact area configured for connection to the busbar. The connecting element further comprises a resilient section between the first contact area and the second contact area, wherein the resilient section is suitable for compensating for any tolerance in the distance between the first contact area and the second contact area.

[0012] The connecting element has the advantage that the two contact areas can be adapted to existing circuit boards or busbars, eliminating the need for modifications. Tolerance compensation is ensured by the spring-loaded section between them. This can reliably compensate for height tolerances of up to approximately 1000 µm, for example. Stresses in the circuit board and busbar are reduced or eliminated.

[0013] The fact that the resilient section is suitable for compensating for tolerances in the distance between the first and second contact areas is achieved by allowing the first and second contact areas to spring against each other via the resilient section, thus enabling their distance to be varied. The spring characteristics of the resilient section are selected accordingly. In particular, the spring must be elastic enough to prevent stress on the contact areas and the connection to the circuit board and the busbar.

[0014] The printed circuit board (PCB) can be designed as a circuit carrier with fiber-reinforced plastic such as prepreg as the insulating base material. Alternatively, the PCB can be designed as a circuit carrier with ceramic material as the insulating base material.

[0015] According to one embodiment of the invention, the first contact area has a number of press-fit pins. Such press-fit pins are already used for connecting printed circuit boards. According to one embodiment, the press-fit pins are integrally formed with the resilient section.

[0016] Alternatively, the first contact area can also have a number of SMD (surface mounted device) solder contacts, i.e., surface-mountable solder contacts, for example in the form of solder deposits.

[0017] Another alternative is THT (through hole technology), i.e., solder contacts that can be mounted through a hole. Alternatively, a screw connection or another type of connection can also be used.

[0018] This allows the first contact area of ​​the connecting element to be implemented using a known and proven technology that is already used for contacting printed circuit boards and is compatible with existing processes.

[0019] According to one embodiment, the second contact area has a thread. This thread serves to receive a screw, which is inserted through a through-hole in the busbar and then screwed into the thread to create an electrically and mechanically stable connection between the busbar and the connecting element. This embodiment has the advantage that the connection is particularly easy to manufacture and simultaneously stable. However, another type of connection between the busbar and the second contact area is also conceivable, for example, a welded connection.

[0020] The resilient section can, for example, comprise a coil spring. Alternatively, the resilient section can have at least one resilient, curved leg. The at least one resilient, curved leg can, in particular, be designed as a curved leaf spring, with the shape and number of bends being adapted to the required spring travel and the available installation space.

[0021] The connecting element can be designed, in particular, as a stamped and bent part. In this embodiment, the connecting element is essentially stamped from a sheet of metal and bent into the required shape. Such stamped and bent parts are easy and cost-effective to manufacture in the required shape.

[0022] According to one aspect of the invention, an assembly is specified comprising at least one printed circuit board with power semiconductor components arranged thereon and at least one busbar for electrically contacting the printed circuit board. The at least one printed circuit board is electrically and mechanically connected to the at least one busbar by means of at least one described connecting element and at least one screw.

[0023] This assembly has the advantage that the busbar is stably and permanently connected to the circuit board. The assembly is particularly suitable for high-power applications where high currents flow.

[0024] According to a further aspect of the invention, an inverter, in particular a power inverter for an electric drive device of a motor vehicle, is provided, comprising at least one previously described assembly. In this case, the power semiconductor components of the assembly are configured as controllable power semiconductor switches, each with a control terminal. The inverter further comprises a control circuit that is electrically connected to the control terminal of the respective power semiconductor switches via signal connections.

[0025] Embodiments of the invention are described below by way of example with reference to schematic drawings. Fig. Figure 1 shows a first view of a connecting element, Fig. Figure 2 shows a second view of the connecting element according to Fig. 1, Fig. Figure 3 shows a third view of the connecting element according to the Fig. 2 and Fig. 3, Fig. Figure 4 shows a first view of another connecting element, Fig. Figure 5 shows a second view of the connecting element according to Fig. 4, Fig. Figure 6 shows a third view of the connecting element according to the Fig. 4 and Fig. 5, Fig. Figure 7 shows a first view of another connecting element, Fig. Figure 8 shows a second view of the connecting element according to Fig. 7, Fig. Figure 9 shows a third view of the connecting element according to the Fig. 7 and Fig. 8, Fig. Figure 10 shows a connecting element connected to a busbar, Fig. Figure 11 shows an embodiment of an assembly according to the invention comprising a busbar and a printed circuit board which are mechanically and electrically connected to each other by a connecting element, and Fig. Figure 12 shows the connection of two circuit boards to each other by means of a busbar and several connecting elements.

[0026] Fig. Figure 1 shows a side view of a connecting element 1 for connecting a busbar to a printed circuit board according to a first embodiment, particularly for power applications. In the embodiment shown, the connecting element 1 is designed as a stamped and bent part made of a metal sheet and serves for an electrically conductive and mechanical connection between a busbar and a printed circuit board, which are not shown in the figure.

[0027] The connecting element 1 has a first contact area 2 for connection to a printed circuit board and a second contact area 4 for connection to a busbar. A resilient section 3 is arranged between the first contact area 2 and the second contact area 4 to compensate for positional or height tolerances.

[0028] The first contact area 1 is formed by a plurality of press-fit pins 5, which can be pressed into provided through holes in the circuit board to simultaneously establish an electrical and mechanical connection to the circuit board.

[0029] The second contact area 4 has a plate 6 with a through-hole 7 designed to receive a screw and featuring an internal thread (not shown in the figures). Alternatively, the through-hole 7 can also be a blind hole. The second contact area 4 is designed to receive a busbar that is placed on the plate 6. A screw can then be inserted through a through-hole in the busbar into the through-hole 7 to connect the busbar to the connecting element 1.

[0030] In the embodiment shown, the resilient section 3 arranged between the contact areas 2, 4 consists of a section of the metal sheet which has various cutouts 8 to form several legs 9 which can be compressed in the vertical direction, i.e. Z-direction, to compensate for height tolerances between the circuit board and the busbar and thus between the first contact area 2 and the second contact area 4.

[0031] Fig. 2 shows the connecting element 1 in a position opposite the one in Fig. Figure 1 shows a side view rotated by 90°. In this view, it can be seen that the connecting element 1 has a U-shaped cross-section and that the first contact area has two opposing rows of press-fit pins 5. This gives the connecting element 1 particularly good stability.

[0032] Fig. Figure 3 shows a perspective view of the connecting element 1 according to the Fig. 1 and Fig. 2.

[0033] Fig. Figure 4 shows a side view of a connecting element 1 according to a second embodiment. This is also designed as a stamped and bent part and differs from the one shown in the Fig. 1 to 3 shown by the design of the springy section 3.

[0034] According to the second embodiment, this has two curved legs 9 on each side, each consisting of a largely horizontal upper section 13, a similarly largely horizontal lower section 14, and an arc 15 connecting sections 13 and 14. The lower section 14 is connected to the first contact area 2, while the upper section 13 is connected to the second contact area 4. The lower section 14 and the upper section 13 are resiliently designed relative to each other, so that the distance between the contact areas 2 and 4 is variable within the limits of the spring travel.

[0035] In this embodiment, the legs 9 project significantly laterally beyond the first contact area 2 and the second contact area 4 and provide a spring travel in the Z direction in the manner of a leaf spring.

[0036] In this embodiment as well, the connecting element has a U-shaped cross-section with two rows of press-fit pins 5, which are opposite each other and between which the second contact area 4 is arranged, as particularly in the Fig. 5 and Fig. 6 is recognizable.

[0037] The Fig. Figures 7 to 9 show a third embodiment of the connecting element 1. This differs from those shown in the Fig. Figures 1 to 6 show the embodiment of the resilient section 3. According to the third embodiment, the resilient section has two legs 9 separated from each other by a cutout 8, which have a spring travel similar to that shown in the Fig. 4 to 6 show the second embodiment, but asymmetrically only on one side.

[0038] In this embodiment as well, the lower section 14 is connected to the first contact area 2, while the upper section 13 is connected to the second contact area 4.

[0039] Fig. Figure 10 shows an assembly 30 with a busbar 10 connected to a connecting element 1 according to a further embodiment. According to this embodiment, the connecting area 3 of the connecting element 1 is designed as a helical spring 11, which is compressible in the Z-direction and is arranged between the first contact area 2 and the second contact area 4. The second contact area 2 is only indicated in this embodiment and could also have press-fit pins, surface-mount contacts, or through-hole contacts.

[0040] To connect the busbar 10 to the connecting element 1, a screw 12 is inserted through the through hole 7 of the connecting element 1 and through a through hole in the busbar 10 and screwed into the through hole 7.

[0041] Fig. Figure 11 shows an embodiment of an assembly 30 according to the invention, comprising a printed circuit board 20 and a busbar 10, which are electrically and mechanically connected to each other via a connecting element 1. The connecting element 1 is as shown in the Fig. Figures 7 to 9 show the component's design. Its press-fit pins 5 are inserted into correspondingly designed through-holes in the circuit board 20.

[0042] A screw 12 is passed through a through-hole 16 in the busbar 10 and through the threaded through-hole 7 of the connecting element 1, and screwed into the through-hole 7. The distance in the Z-direction between the circuit board 20 and the busbar 10 can be compensated for by the spring travel of the spring section 3.

[0043] Fig. Figure 12 shows an assembly 30 consisting of two printed circuit boards 20, which are connected to each other via a busbar 10, the busbar 10 being connected to each of the printed circuit boards 20 via the in Fig. 11. Connecting element 1 is connected. As shown in Fig.As can be seen from Figure 12, the connecting elements 1 can also be used to connect printed circuit boards 20 at different levels, which are connected to each other via curved busbars 10, in a tolerance-compensating manner. In such arrangements, the additive height and positional tolerances can become considerable, making the use of the connecting element 1 particularly advantageous.

[0044] The assembly 30, for example, is part of a power inverter for an electric drive system of a motor vehicle, which, in addition to the assembly 30, also includes a control circuit. In this case, the power semiconductor components are configured as controllable power semiconductor switches, each with a control terminal. The control circuit is electrically connected to the control terminal of the respective power semiconductor switches via signal connections. Reference symbol list 1 connecting element 2 first contact area 3 spring section 4 second contact area 5 press-in pins 6 plates 7 through hole 8 Excerpt 9 thighs 10 busbar 11 coil spring 12 screws 13 upper section 14 lower section 15 sheets 16 through hole 20 circuit boards 30 assembly

Claims

[1] Assembly (30) comprising, - at least one printed circuit board (20) with power semiconductor components arranged on it; - at least one busbar (10) for electrical contacting the printed circuit board (20), wherein - which is electrically and mechanically connected to at least one circuit board (20) and at least one busbar (10) by means of at least one connecting element (1) and at least one screw (12), and - which has at least one connecting element (1): - a first contact area (2) formed for connection with the printed circuit board (20), - a second contact area (4) designed for connection to the busbar (10) and - a resilient section (3) between the first contact area (2) and the second contact area (4), wherein the resilient section (3) is suitable to compensate for a tolerance of a distance between the first contact area (2) and the second contact area (4). [2] Assembly (30) according to claim 1, wherein the first contact area (2) has a number of press-fit pins (5). [3] Assembly (30) according to claim 1, wherein the first contact area (2) has a number of SMD solder contacts. [4] Assembly (30) according to claim 1, wherein the first contact area (2) has a number of THT solder contacts. [5] Assembly (30) according to one of claims 1 to 4, wherein the second contact area (4) has a thread. [6] Assembly (30) according to any one of claims 1 to 5, wherein the resilient section (3) comprises a helical spring (11). [7] Assembly (30) according to any one of claims 1 to 6, wherein the resilient section (3) has at least one resilient, curved leg (9). [8] Assembly (30) according to claim 7, wherein the connecting element (1) is designed as a stamped and bent part. [9] Inverter, comprising, - an assembly (30) according to one of claims 1 to 8, wherein the power semiconductor components are formed as controllable power semiconductor switches, each with a control terminal, - a control circuit, wherein the control circuit is electrically connected to the control terminal of the respective power semiconductor switches via signal connections.

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