Contacting a power semiconductor module

Abstract

The present invention relates to a device (12) for electrically contacting a power semiconductor module (10), comprising: a first contact line (20) and a second contact line (22), each having a first contact section (28) at their first ends and a second contact section (30) at their second ends; an insulating layer (24) surrounding the second contact line (22) in order to mechanically stabilize the second contact line (22); and an electromagnetic shield (26) surrounding the insulating layer (24) and the second contact line (22) at least in sections and being electrically conductively connected to the first contact line (20). The present invention further relates to a method for producing a device (12) for electrically contacting a power semiconductor module (10).

Description

[0001] The present invention relates to a device for contacting a power semiconductor module. The present invention further relates to a method for manufacturing the device.

[0002] The power electronics of electric and hybrid vehicles transfer the traction energy from the battery to the electric motor, converting direct current into alternating current. An AC converter, also known as an inverter, or traction converter, is used for this purpose. Typically, several transistors or other power semiconductors are used, combined to form a power semiconductor module that switches at short, regular intervals. MOSFETs (metal oxide semiconductor field-effect transistors) and IGBTs (insulated gate bipolar transistors) are used as switches in this context. When switched on, the battery current is transferred to the motor (conduction phase). These high-frequency switching processes create an alternating voltage profile, which can then be converted into traction energy in the electric motor.To increase the current carrying capacity, several power semiconductors are usually connected in parallel.

[0003] Such power semiconductor modules or power semiconductors in this or other applications switch comparatively high currents, and the switching power semiconductors generate high temperatures. Active cooling systems are often used to dissipate switching and power losses. In current inverter designs, modules are connected to a corresponding driver board via soldered or press-fitted pins. These pins can be very long, especially in designs with double-sided module cooling. The length of the pins or contact lines poses a challenge for module manufacturing as well as for assembly in an inverter system.

[0004] One challenge due to the long pin length is the high cost of producing the modules, as well as transporting them to prevent damage. Furthermore, the length of the individual pins complicates assembly in power electronics. Positioning precision is limited by the inherent stability of the pins. Furthermore, as pin length increases, interference is more easily coupled, which can complicate controlling the semiconductors.

[0005] Based on this, the present invention aims to provide an approach for contacting a power semiconductor module. In particular, an efficient and mechanically robust contact system is to be provided that also protects contact points and cables during transport of semi-finished products and can preferably counteract the coupling of interference currents.

[0006] To achieve this object, the present invention relates in a first aspect to a device for electrically contacting a power semiconductor module, comprising: a first contact line and a second contact line, each having a first contact section at its first ends and a second contact section at its second ends; an insulation layer which surrounds the second contact line at least in sections in order to mechanically stabilize the second contact line; and an electromagnetic shield which surrounds the insulation layer and the second contact line at least in sections and is electrically connected to the first contact line.

[0007] In a further aspect, the present invention relates to a method for producing a device for electrically contacting a power semiconductor module, preferably a device as defined above, comprising the steps: - Providing a sheet metal which serves as a shield for a second contact line of the device for contacting a power semiconductor module and is connected to a first contact line; - forming the sheet into a tube at least in sections around the second contact line; - joining two edges of the formed sheet to form a closed surface, in particular in the form of a cylindrical surface; and - Inserting insulation between the sheet and the second contact line to form an insulating layer.

[0008] Preferred embodiments of the invention are described in the dependent claims. It is understood that the features mentioned above and those to be explained below can be used not only in the respective combinations specified, but also in other combinations or alone, without departing from the scope of the present invention. In particular, the device and / or the method can be designed according to the embodiments described in the dependent claims.

[0009] According to the invention, the device for electrically contacting a power semiconductor module comprises at least two contact lines, of which a first contact line is electrically connected to an electromagnetic shield. The electromagnetic shield surrounds the second contact line at least in sections.

[0010] An insulating layer is arranged between the electromagnetic shield and the second contact line. This insulating layer ensures that the second contact line is electrically insulated from the first contact line. Furthermore, contact lines of great length can be manufactured because the insulation provides mechanical stability. In particular, it prevents the contact lines from being bent during manufacturing, installation, and / or transport or storage. Precise alignment of the two contact lines relative to each other can be achieved. The two contact lines are mechanically connected to each other by means of the insulating layer and the electromagnetic shield.

[0011] It is understood that the contact lines, including specially designed contact sections such as press-fit pins or solder pins, can be manufactured in one piece, for example, in a stamping and bending process. In particular, the electromagnetic shielding can also be formed in one piece with the first contact line. Particularly preferably, the insulation layer comprises a plastic that can be introduced in liquid form into a cylinder formed by the electromagnetic shielding and subsequently cured.

[0012] By providing a sheet metal connected to a first contact line, an efficient process can be created. In particular, it is conceivable to produce the contact sections, the shielding, and preferably two contact lines as a single piece in a stamping and bending process. It is understood that manufacturing aids can be provided for this purpose to connect and secure the individual components together. The manufacturing aids can be easily removed after the manufacturing process.

[0013] In a preferred embodiment, the first contact line and the electromagnetic shield are formed as a single piece and are particularly preferably manufactured using a stamping and bending process. This allows for the creation of a cost-effective device that can be quickly produced in large quantities.

[0014] Advantageously, a base body of the electromagnetic shield is a rectangular sheet metal that is bent around the insulation layer to form a lateral surface around the insulation layer, at least in sections. This can increase the mechanical stability of the device. In particular, the electromagnetic shield can serve both to provide mechanical stability and to prevent interference currents. A single component can improve both the electrical and mechanical properties of the device.

[0015] Particularly preferably, the rectangular sheet metal is welded and / or soldered to form a lateral surface. This can further increase mechanical robustness. Furthermore, improved electromagnetic shielding can be achieved through welding or soldering, since these connections are typically electrically conductive.

[0016] Preferably, the electromagnetic shielding can be formed as a wire mesh. This allows the electromagnetic shielding to be molded onto the insulation layer with minimal effort. In particular, a wire mesh can have improved shielding properties. Furthermore, this allows for material savings, thus creating a lightweight and cost-effective device.

[0017] In a particularly preferred embodiment, the first contact section and / or second contact section are each formed as a press-fit pin and / or a solder pin. Particularly preferably, the formation of the contact section, press-fit pin and / or solder pin, can be carried out in a stamping and / or stamping-bending process, so that the device can be manufactured with few work steps. By using press-fit pins and / or solder pins, a method established in the prior art for making electrical contact can be applied by means of the device. A device for a broad range of applications can be created.

[0018] In a particularly preferred embodiment, the device comprises an additional contact line, wherein the additional contact line is arranged in the insulation layer and surrounded by the electromagnetic shield. Preferably, the additional contact line is shielded by an additional shield. This allows the contacting device to be easily expanded to three and / or more contact lines. Nevertheless, both shielding and mechanical stability are maintained.

[0019] In a preferred embodiment of the method, the step of introducing insulation between the sheet metal and the second contact line comprises wrapping the second contact line with an insulator. This step is preferably performed before the steps of forming the sheet metal into a tube, at least in sections, around a second contact line and connecting the edges of the formed sheet metal to form a lateral surface.

[0020] The present invention presents a concept for contacting a power semiconductor module and a control board, which: - allows flexible installation distance; - has fewer tolerance problems; and - enables lower electromagnetic coupling.

[0021] The inventive concept enables contacting which minimizes electromagnetic coupling by a shielding system comprising a central conductor, i.e. the second contact line, with a surrounding secondary conductor, i.e. the second contact line and electromagnetic shielding.

[0022] For mechanical stabilization and insulation, an intermediate space is filled with an insulating material, e.g. a plastic, and if necessary, elements are also formed in the exterior and for fastening purposes.

[0023] The contact is preferably designed as a press-fit pin to allow for press-fitting into both a module and a circuit board. This also simplifies the modules.

[0024] The component can be manufactured from sheet metal. In a first step, the sheet metal is cut and / or punched. In a second step, the sheet metal is rolled and / or bent into a tube. The butt edges of the sheet metal can be welded or soldered. In a third step, the stabilizing or insulation is applied. In a final manufacturing step, the manufacturing aids can be removed.

[0025] As an alternative manufacturing option, the assembly proceeds from the inside out. First, the second conductor, i.e., the second contact line, which can be copper wire, for example, is wrapped with a plastic, such as PTFE. This is followed by wrapping with the shielding material. Finally, the contact points, such as the press-fit pins, are manufactured.

[0026] It goes without saying that further embodiments are conceivable.

[0027] In addition to press-fit pins, soldering variants can also be implemented.

[0028] Instead of a solid screen, this can also be made as a wire mesh.

[0029] Several twisted cables can be routed in the center, surrounded with or without a shielded sheath.

[0030] Herein, a power semiconductor module is understood to be, in particular, an assembly for use in an inverter structure. A power semiconductor module typically comprises several individual power semiconductors or chips. A power semiconductor is, in particular, an electronic chip that has one or more integrated circuit components. For example, insulated-gate bipolar transistors or other semiconductors can be used.

[0031] The power semiconductor module can in particular be designed to be flat and comprise a plurality of power semiconductors which are also designed to be flat.

[0032] Press-fit pins, contact pins, or contact pins are used in press-fit technology for solderless connections on printed circuit boards. The contact pin is pressed into a metallized hole in a circuit board. This process is known as through-hole plating. This process can ideally eliminate the need for additional mechanical fastening. The counterpart of the electrical connection of the press-fit contact can be, for example, a wire-wound connection, a blade receptacle, a threaded stud, or a connector. The diagonal of the pin cross-section is larger than the diameter of the hole in the circuit board. By pressing or cutting the pin edges into the metallization of the through-hole plating on the circuit board, an electrical connection is created that, when properly executed, is characterized by high reliability and durability.The over-compression that occurs during pressing can be absorbed either by the deformation in the hole or the deformation of the pin.

[0033] A solder pin is a contact section designed and intended to be soldered to a corresponding receptacle. For this purpose, the solder pin can have an optimized geometry.

[0034] The invention is described and explained in more detail below using selected embodiments in conjunction with the accompanying drawings. They show: Fig. 1 A schematic representation of a power semiconductor module which is electrically contacted by means of a device; Fig. 2a - 2d schematically show individual processing steps for producing a device for electrical contacting; Fig. 3a - 3d schematic processing steps of an alternative production of a device for electrical contacting; and Fig. 4 schematically shows the steps of a method for producing a device for electrically contacting a power semiconductor module;

[0035] In Fig. 1 schematically shows a power semiconductor module 10 and a device 12 for electrically contacting the power semiconductor module 10.

[0036] The power semiconductor module 10 comprises a line section 14 and a contact area 16. In the example shown, receiving devices 18 for press-fit pins are arranged in the contact area 16. It is understood that the power semiconductor module 10 is shown only schematically and in a simplified manner.

[0037] The device 12 comprises a first contact line 20 and a second contact line 22. The second contact line 22 is surrounded by an insulating layer 24.

[0038] The insulation layer 24 can be a cured plastic, for example. It is surrounded by an electromagnetic shield 26, which is conductively connected to the first contact line 20. Particularly preferably, the electromagnetic shield 26 is formed integrally with the first contact line 20.

[0039] The insulation layer 24 electrically insulates the second contact line 22 from the first contact line 20. In addition, the insulation layer 24 mechanically stabilizes the first and second contact lines 20, 22.

[0040] A relative position of the first contact line 20 to the second contact line 22 can be precisely adjusted by the described design of the device 12 and reliably maintained during transport, storage, manufacture and assembly.

[0041] The first contact line 20 and the second contact line 22 each have first contact sections 28 and second contact sections 30 at their ends, on which press-fit pins 32 are arranged in the example shown.

[0042] Particularly preferably, the press-fit pins 32 can be formed integrally with the respective contact lines 20, 22. They can then be manufactured, formed, or molded, for example, in a stamping and bending process.

[0043] The press-fit pins 32 are pressed into the receiving devices 18 for contacting the power semiconductor module 10. For reasons of clarity, only a single device 12 is shown in the figure.

[0044] In the Fig. 2a - 2d show individual processing steps for producing a device 12.

[0045] In Fig. Figure 2a shows an initial state. In the example shown, the first contact line 20 is formed integrally with a rectangular sheet metal element 34. The contact sections 28, 30 each have press-fit pins, on each of which a manufacturing aid 36 is arranged to fix the second contact line 22 in its position relative to the first contact line 20.

[0046] In a further processing step, the result of which is Fig. As shown in Figure 2b, the sheet metal 34 is bent around the second contact line 22. In the example shown, the sheet metal 34 forms a peripheral surface of the cylinder, which at least partially surrounds the second contact line 22. The bent sheet metal 34 can be welded and / or soldered at the abutting edges to form a closed peripheral surface. It is understood that other geometries are also conceivable instead of a cylinder.

[0047] In a further processing step, which Fig. As shown in Figure 2c, the cylinder formed by the bent sheet metal 34 is filled with an insulation layer 24. Particularly preferred is a plastic or resin, which can be introduced into the cylinder in a liquid state and subsequently cured. It is understood that ceramic insulation is also conceivable.

[0048] In a further processing step, which Fig. 2d, the manufacturing aids 36 can be removed.

[0049] In a particularly preferred embodiment, the first contact line 20 and the second contact line 22 as well as the sheet metal 34, the press-fit pins and the manufacturing aids 36 can be formed in one piece, wherein the manufacturing aids 36 comprise predetermined breaking points in order to be removed in the last processing step.

[0050] It is understood that manufacturing aids 36 made of an electrically insulating material may also be provided. These manufacturing aids 36 do not necessarily have to be removed.

[0051] In the Fig. 3a - 3d an alternative manufacturing method for a further embodiment of a device 12 is shown schematically.

[0052] In Fig. 3a shows the second contact line 22 and an insulation layer 24 that is not yet fully formed. The insulation layer can, for example, comprise a plastic tape, in particular PTFE.

[0053] In Fig. 3b shows a processing step in which the insulation layer 24 is wound around the second contact line 22.

[0054] In Fig. 3c shows, in addition to the wrapped second contact line 22, the first contact line 20 and a sheet metal element 34 connected to the first contact line 20.

[0055] The sheet 34 can be in a further step, the result of which is Fig. 3d, the sheet metal 34 can be bent around the insulation layer 24. This creates an electromagnetic shield 26 that surrounds the insulation layer 24 and the second contact line 22 at least in sections. It is understood that in this embodiment, too, the sheet metal 34 can be soldered and / or welded, for example, at the abutting edges.

[0056] In contrast to the Fig. The process shown in Figures 2a - 2d is carried out in the Fig. 3a - 3d a structure from the inside, with respect to the second contact line 22.

[0057] In Fig. Figure 4 schematically shows the steps of a method according to the invention.

[0058] In a first step S10, a sheet metal is provided which serves as a shield for a second contact line of a device for contacting a power semiconductor module and is connected to a first contact line.

[0059] Preferably, the sheet metal is formed integrally with the first contact line and is produced, for example, by means of a stamping process.

[0060] In a subsequent second step S20, the sheet metal is formed into a tube which surrounds the second contact line at least in sections.

[0061] In a third step S30, two edges of the formed sheet are joined to form a closed shell surface.

[0062] The lateral surface is preferably cylindrical. Of course, other geometries are also conceivable.

[0063] In a fourth step S40, insulation is introduced between the sheet metal and the second contact line. Preferably, a liquid material is poured into the tube formed by the sheet metal and cured to form an insulation layer.

[0064] This is followed by a separation of production aids in an optional fifth step S50.

[0065] In a further optional sixth step S60, press-fit pins and / or solder pins are molded or attached to contact sections of the first and / or second contact line.

[0066] It is understood that the optional sixth step S60 is not necessarily performed at the end of the method. In particular, the optional sixth step S60 can be performed at the beginning of the method or during the method.

[0067] The step of inserting insulation between the sheet metal and the contact lead can, on the one hand, involve pouring liquid plastic. On the other hand, wrapping the second contact lead with an insulator is also conceivable. It is understood that the aforementioned steps do not necessarily have to be performed in the order mentioned here.

[0068] The invention has been comprehensively described and explained with reference to the drawings and the description. The description and explanation are to be understood as exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other embodiments or variations will become apparent to those skilled in the art upon use of the present invention and upon careful analysis of the drawings, the disclosure, and the following claims.

[0069] In the claims, the words "comprising" and "having" do not exclude the presence of further elements or steps. The undefined article "a" or "an" does not exclude the presence of a plurality. A single element or unit can perform the functions of several of the units recited in the claims. The mere reciting of some measures in several different dependent claims should not be understood to mean that a combination of these measures cannot also be used advantageously. Reference signs in the claims are not to be understood as limiting. Reference symbol 10 power semiconductor modules 12 Device 14 line sections 16 Contact area 18 Mounting device 20 first contact line 22 second contact line 24 Insulation layer 26 electromagnetic shielding 28 first contact section 30 second contact section 32 press-fit pin 34 sheet metal 36 Manufacturing aid S10-S60 process steps

Claims

[1] Device (12) for electrically contacting a power semiconductor module (10), comprising: a first contact line (20) and a second contact line (22), each having a first contact section (28) at its first ends and a second contact section (30) at its second ends; an insulation layer (24) surrounding the second contact line (22) to mechanically stabilize the second contact line (22); and an electromagnetic shield (26) which surrounds the insulation layer (24) and the second contact line (22) at least in sections and is electrically conductively connected to the first contact line (20). [2] Device (12) according to claim 1, wherein the first contact line (20) and the electromagnetic shield (26) are formed in one piece and are preferably manufactured by means of a stamping and bending process. [3] Device (12) according to one of the preceding claims, wherein a base body of the electromagnetic shield (26) comprises a rectangular sheet (34) which is bent around the insulation layer (24) in order to form, at least in sections, a lateral surface around the insulation layer (24). [4] Device (12) according to claim 3, wherein the rectangular sheet (34) is welded and / or soldered to form a lateral surface. [5] Device (12) according to claim 1, wherein the electromagnetic shield (26) is designed as a wire mesh. [6] Device (12) according to one of the preceding claims, wherein the first contact section (28) and / or the second contact section (30) are each designed as a press-fit pin (32) and / or as a soldering pin. [7] Device (12) according to one of the preceding claims, with a further contact line, wherein the further contact line is arranged in the insulation layer (24) and is surrounded by the electromagnetic shield (26) and is preferably shielded by means of a further shield. [8] Method for producing a device (12) for electrically contacting a power semiconductor module (10), preferably a device (12) according to one of the preceding claims, comprising the steps: - Providing (S10) a sheet (34) which serves as a shield for a second contact line (22) of the device (12) for contacting a power semiconductor module (10) and is connected to a first contact line (20); - forming (S20) the sheet metal (34) into a tube at least in sections around the second contact line (22); - joining (S30) two edges of the formed sheet (34) to form a closed shell surface; and - introducing (S40) an insulation between the sheet (34) and the second contact line (22) in order to form an insulation layer (24). [9] Method according to the preceding claim, wherein the step of “introducing (S40) an insulation between the sheet metal (34) and the second contact line (22)” comprises wrapping the second contact line (22) with an insulator and is preferably carried out before the steps of “forming (S20) the sheet metal into a tube at least in sections around a second contact line” and “connecting (S30) the edges of the formed sheet metal (34) to form a jacket surface”. [10] Method according to one of claims 8 or 9, comprising the step of forming (S60) press-fit pins (32) and / or solder pins on contact sections (28, 30) of the first contact line (20) and / or the second contact line (22).

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