Solder / press-fit pin for electrically contacting a power module with a circuit board in an electric vehicle

Abstract

The present invention relates to a solder / press-fit pin for electrically contacting a power module in an electric vehicle, comprising a tip at a first end along a longitudinal axis of the solder / press-fit pin, a mounting area at a second end along the longitudinal axis and an elongated body between the tip and the mounting area, wherein the mounting area at the second end has a welding surface oriented perpendicular to the longitudinal axis, and wherein the mounting area has a contact surface configured to contact a sonotrode in order to form a metallurgical bond at the welding surface by ultrasonic welding.

Description

State of the art

[0001] The present invention relates to a solder / press-fit pin for electrically contacting a power module or a printed circuit board in an inverter module of an electric vehicle, and to a method for manufacturing the inverter module.

[0002] For electrical contacting a power module, solder / press-fit pins are typically applied to the module and then soldered or laser-welded to it. Positioning these pins is complex and requires precise component tolerances. Furthermore, securing the solder / press-fit pin by soldering or laser welding necessitates a defined position on the power module. A solder / press-fit pin that can be easily and cost-effectively attached to a power module using ultrasonic welding would be desirable. Disclosure of the invention

[0003] The soldering or press-fit pin according to the invention, comprising the features of claim 1, the inverter module according to the invention, comprising the features of claim 9, and the method according to the invention, comprising the features of claim 12, have the advantage that a soldering or press-fit pin with a simple and cost-effective geometry can quickly and reliably form a metallurgical bond with a power module by means of ultrasonic welding. The soldering / press-fit pin requires no complex arrangement or fixation and can easily compensate for tolerances. This is achieved according to the invention by the soldering / press-fit pin comprising a tip, a mounting area, and an elongated body. The tip is arranged at a first end along a longitudinal axis of the soldering / press-fit pin, and the mounting area is arranged at a second end along the longitudinal axis of the soldering / press-fit pin.The elongated body is positioned between the tip and the mounting area, specifically directly adjacent to both. At its other end, the mounting area features a welding surface oriented perpendicular to its longitudinal axis. Furthermore, the mounting area has a contact surface designed to engage a sonotrode, enabling ultrasonic welding to create a metallurgical bond at the welding surface. This allows the sonotrode to be easily positioned on the solder / press-fit pin, thus metallurgically bonding it to a power module. The solder / press-fit pin can then be pressed into a corresponding opening in a printed circuit board via its tip, establishing an electrical and mechanical connection between the two components. The power modules could, for example, be a power module for controlling an electric motor and an associated control unit for that power module.

[0004] The dependent claims describe preferred embodiments of the invention.

[0005] Preferably, the contact surface is aligned parallel to the welding surface. This allows a force from the sonotrode to be efficiently transferred to the welding surface.

[0006] The solder / press-fit pin is preferably a stamped component. This allows for fast and cost-effective mass production of the solder / press-fit pins. A fine-blanked component is particularly preferred. A fine-blanked component is characterized by a very high proportion of smooth cut and minimal burrs, resulting in a weld surface that is as flat as possible and reliably forms a metallurgical bond. Preferably, the weld surface is a stamped surface.

[0007] Preferably, the fastening area is formed by a 90° bend along a bending axis, the bending axis being perpendicular to the longitudinal axis. This allows the size of the contact area and the weld area to be easily increased, thus improving the mechanical properties of the bonded connection. In particular, this allows the width and depth of the contact area and the weld area to be increased.

[0008] Preferably, the elongated body has a constant cross-section perpendicular to its longitudinal axis. The cross-section is particularly rectangular. This constant, especially rectangular, cross-section allows the solder / press-fit pin to be reliably pressed into its corresponding opening.

[0009] The weld area is preferably larger than the maximum cross-section of the elongated body perpendicular to its longitudinal axis. In particular, the weld area is more than twice as large. This improves the mechanical properties of the soldered / press-fit pin in its joined state.

[0010] The elongated body is preferably ten to twenty times longer along its longitudinal axis than the mounting area. This allows for reliable contact between the power module and the circuit board even at a greater distance.

[0011] Preferably, the contact surface extends from two opposite sides of the elongated body. The solder / press-fit pin is T-shaped, particularly when viewed perpendicular to the longitudinal axis. This shape can be produced very easily and cost-effectively in a stamping process and can enable a reliable connection in the ultrasonic process.

[0012] The invention further relates to an inverter module for an electric vehicle, comprising a printed circuit board and a power module with a contact surface, wherein the contact surface is metallurgically bonded to a welded surface of a previously described solder / press-fit pin. The contact surface is larger than the welded surface, in particular at least twice as large, to allow for tolerance compensation of the solder / press-fit pin perpendicular to its longitudinal axis. Furthermore, the solder / press-fit pin is connected to the printed circuit board by means of a solder or press-fit connection. This ensures reliable contact of the first end of the solder / press-fit pin and reduces rejects.

[0013] The contact surface is preferably arranged with a recess in a sheath. The sheath can protect the circuit board from environmental influences, and the shape of the solder / press-fit pin according to the invention allows it to be reliably secured in a small recess.

[0014] Preferably, the inverter module comprises a heat sink with a reference element for geometric referencing. The power modules are arranged on the heat sink, with the solder / press-fit pin positioned on the contact surface in geometric relation to the reference element. This eliminates placement tolerances between the heat sink and the power module, as the solder / press-fit pins are only attached to the power module relative to the heat sink. The reference element can be, for example, a marking or a bore. Particularly preferably, the heat sink or the power module has multiple reference elements.

[0015] Furthermore, the invention relates to a method for manufacturing the inverter module described above. In the method, the solder / press-fit pin described above is manufactured in a first step. Subsequently, the solder / press-fit pin is bonded to a contact surface of a power module of the inverter module by means of ultrasonic welding. This allows a simple and reliable bond to be formed between the solder / press-fit pin and the power module in order to manufacture a power module.

[0016] The solder / press-fit pin is preferably manufactured using a stamping process, particularly a fine blanking process. This allows for simple and cost-effective production of the solder / press-fit pin for the inverter module.

[0017] Furthermore, the method preferably includes the step of arranging the power module on a heat sink with a reference element. The solder / press-fit pin is then bonded to the contact surface in a manner geometrically dependent on the reference element. This eliminates tolerance chains and allows the solder / press-fit pin to be attached to the contact surface of the power module with high accuracy relative to the heat sink. Brief description of the drawings

[0018] Preferred embodiments of the invention are described in detail below with reference to the accompanying drawings. The drawing shows: Fig. 1 a schematic, perspective view of the solder / press-fit pin according to a first embodiment of the invention, Fig. 2 a schematic, perspective view of a solder / press-fit pin according to a second embodiment of the invention on a printed circuit board and Fig. 3 a schematic view of a power module with a solder / press-fit pin according to the first embodiment of the invention. Embodiments of the invention

[0019] Preferably, all identical components, elements and / or units in all figures are provided with the same reference numerals.

[0020] Below, with reference to the Fig. 1 to 3 describe in detail an inverter module 100 with a soldering or press-fit pin and a method for manufacturing the inverter module 100.

[0021] Fig. Figure 1 shows a solder / press-fit pin 1 for electrically contacting the inverter module 100 in an electric vehicle. The solder / press-fit pin 1 has a T-shaped form extending along a longitudinal axis XX. At a first end 11 along the longitudinal axis XX, the solder / press-fit pin 1 has a tip 2. The tip 2 allows the solder / press-fit pin 1 to be pressed into a corresponding opening in a printed circuit board to make electrical and mechanical contact.

[0022] At a second end 12 along the longitudinal axis XX, the solder / press-fit pin 1 has a mounting area 3. The mounting area 3 has a welding surface 5 at its second end 12, which is oriented perpendicular to the longitudinal axis XX. Furthermore, the mounting area has a contact surface 6. The contact surface 6 is aligned parallel to the welding surface 5 and is designed to contact a sonotrode in order to form a metallurgical bond at the welding surface 5 by means of ultrasonic welding. For this purpose, the sonotrode is pressed onto the contact surface 6 to transmit its vibrations in the ultrasonic range to the welding surface 5 of the solder / press-fit pin 1. The frictional heat generated by the vibrations melts the welding surface 5 to form a metallurgical bond with a printed circuit board.

[0023] An elongated body 4 is arranged directly adjacent to the tip 2 and the mounting area 3. The elongated body 4 has a uniform rectangular cross-section perpendicular to its longitudinal axis. The elongated body 4 is approximately thirteen times longer along its longitudinal axis XX than the mounting area 3.

[0024] The contact surface 6 extends equally from two opposite sides of the elongated body 4. Thus, the solder / press-fit pin 1 has a flat T-shaped form. The solder / press-fit pin 1 can be mass-produced cost-effectively as a stamped component. The tip 2 can, for example, be manufactured using a forming process.

[0025] The welding surface 5 is more than twice the size of the maximum cross-section of the elongated body 4 perpendicular to the longitudinal axis XX. The contact surfaces 6, which each extend away from the elongated body 4, are approximately the same size as the maximum cross-section of the elongated body 4.

[0026] Fig. Figure 2 shows the solder / press-fit pin 1 according to a second embodiment. The second embodiment differs from the first embodiment in that Fig. 1 essentially by the fastening area 3. The fastening area 3 has a 90° bend 7 along a bending axis YY. The bending axis YY is oriented perpendicular to the longitudinal axis XX. This allows the welding surface 5 and the contact surface 6 of the fastening area 3 to be enlarged compared to the first embodiment. The solder / press-fit pin 1 can still be manufactured cost-effectively in a stamping process, with the fastening area 3 formed by the 90° bend 7 being produced in a subsequent process step.

[0027] The solder / press-fit pin 1 is arranged on a contact surface 9 of a power module 8. The power module 8 has a casing, the contact surface 9 being arranged in a recess 10 of the casing. The contact surface 9 is preferably made of a metal or metallized.

[0028] The contact surface 9 is at least twice as large as the welding surface 5, so that a tolerance compensation of the soldering / press-in pin 1 perpendicular to the longitudinal axis XX can be enabled.

[0029] The mounting area 3 is U-shaped when viewed in the direction of the longitudinal axis XX, with the elongated body 4 arranged centrally to the mounting area 3 and connected to the lower leg of the U-shaped mounting area 3. The elongated body 7 was arranged in the open area of ​​the U-shaped mounting area 3 upstream of the 90° bend 7.

[0030] Fig. Figure 3 schematically shows an inverter module 100 with a cooler 13, on which three power modules 8 are arranged. The power modules 8 preferably comprise power semiconductors. Solder / press-fit pins 1 are arranged on contact surfaces 9 of the power modules 8. The power modules 8 can electrically contact a printed circuit board by means of the solder / press-fit pins 1.

[0031] The cooler 13 has a reference element 14 for geometric referencing in both a left and a right edge region. The reference element 14 is designed as a bore. The solder / press-fit pins 1 can be arranged on the contact surfaces 9 in geometric dependence on the reference elements 14. When electrically contacting a printed circuit board (PCB) using the solder / press-fit pins 1, the power module can preferably be aligned on the cooler 13 using the reference elements 14 and then electrically and mechanically connected to the PCB by soldering or pressing the solder / press-fit pins 1 into corresponding openings. Thus, the positional tolerance of the power modules 8 on the cooler 13 can be neglected when contacting another PCB.

[0032] To manufacture the inverter 100, the solder / press-fit pin 1 is produced in a first step, particularly using a fine blanking process. In a further step, the printed circuit board 8 is positioned on a heat sink 13 with a reference element 14 and preferably directly attached. The solder / press-fit pin 1 is then bonded to the contact surface 9 by ultrasonic welding, its geometry relative to the reference element 14 creating a material bond. This allows for the simple and cost-effective production of a power module 100 configured to electrically contact a printed circuit board via the solder / press-fit pins 1.

Claims

[1] Solder / press-fit pin for electrically connecting a power module (1) to a printed circuit board in an electric vehicle, comprising: - a tip (2) at a first end (11) along a longitudinal axis (XX) of the solder / press-fit pin (1), - a fastening area (3) at a second end (12) along the longitudinal axis (XX) and - an elongated body (4) between the tip (2) and the attachment area (3), - wherein the fastening area (3) at the second end (12) has a weld surface (5) which is oriented perpendicular to the longitudinal axis (XX), and - wherein the fastening area (3) has a contact surface (6) which is designed to contact a sonotrode in order to form a materially bonded connection at the welding surface (5) by means of ultrasonic welding. [2] Soldering / press-in pin according to claim 1, wherein the contact surface (6) is aligned parallel to the welding surface (5). [3] Solder / press-fit pin according to one of the preceding claims, wherein the solder / press-fit pin (1) is a stamped component. [4] Solder / press-fit pin according to one of the preceding claims, wherein the fastening area (3) is formed by a 90° bend (7) along a bending axis (YY) which is oriented perpendicular to the longitudinal axis (XX). [5] Soldering / press-in pin according to one of the preceding claims, wherein the elongated body (4) has a constant cross-section perpendicular to the longitudinal axis (XX), in particular a rectangular cross-section. [6] Soldering / press-in pin according to one of the preceding claims, wherein the welding area (5) is larger than a maximum cross-section of the elongated body (4) perpendicular to the longitudinal axis (XX), in particular more than twice as large. [7] Solder / press-fit pin according to one of the preceding claims, wherein the elongated body (4) is 10 to 20 times longer along the longitudinal axis (XX) than the fastening area (3). [8] Solder / press-fit pin according to one of the preceding claims, wherein the bearing surface (6) extends away from two opposite sides of the elongated body (4). [9] Inverter module for an electric vehicle, comprising a printed circuit board and a power module (8) with a contact surface (9), wherein the contact surface (9) is metallurgically bonded to a weld surface (5) of a solder / press-fit pin (1) according to one of the preceding claims, wherein the contact surface (9) is larger than the weld surface (5), in particular at least twice as large, to allow for tolerance compensation of the solder / press-fit pin (1) perpendicular to the longitudinal axis (XX), and wherein the solder / press-fit pin (1) is connected to the printed circuit board by means of a solder or press-fit connection. [10] Inverter module according to claim 9, wherein the contact surface (9) is arranged in a recess (10) of a casing. [11] Inverter module according to one of claims 9 or 10, comprising a cooler (13) with a reference element (14) for geometric referencing, wherein the cooler (13) is arranged on the power module (8) and wherein the solder / press-fit pin (1) is arranged on the contact surface (9) in geometric dependence on the reference element (14). [12] Method for manufacturing the inverter module (100) according to any one of claims 9 to 11, comprising the steps: - Manufacturing a solder / press-fit pin (1) according to any one of claims 1 to 8, - material-bonded joining of the solder / press-fit pin (1) to a contact surface (9) of a power module (8) by means of ultrasonic welding and - Pressing or soldering the solder / press-fit pin to a printed circuit board. [13] Method according to claim 12, wherein the solder / press-in pin (1) is produced in a stamping process. [14] Method according to one of claims 12 or 13, comprising the step: - Arranging the power module (8) on a cooler (13) with a reference element (14), - wherein the solder / press-fit pin (1) is connected to the contact surface (9) in a materially bonded manner in geometric dependence on the reference element (14).

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