Base plate and single-phase module of an inverter, inverter and power electronics

Abstract

A base plate of a single-phase or multi-phase module of an inverter of an electric drive of an at least partially electrically driven vehicle is proposed, wherein the base plate is formed from at least two subassemblies, of which a first subassembly is formed as a basic structure in lightweight construction, and a second subassembly is formed as at least one heat-conducting element integrated into the basic structure, which has one or more receiving regions for fastening a respective semiconductor package on an upper side and a cooling structure on a lower side opposite the upper side, wherein the cooling structure is arranged at least in the region of the receiving region(s).

Description

[0001] The present invention relates to the field of electromobility, in particular to electronic modules for an electric drive.

[0002] The use of electronic modules, such as power electronics modules, in motor vehicles has increased significantly in recent decades. This is due on the one hand to the need to improve fuel economy and vehicle performance, and on the other hand to advances in semiconductor technology. The main components of such an electronic module, also known as power electronics, are an electronic control unit (ECU), which is connected to or forms part of the vehicle's control unit(s) and receives control signals and / or information based, for example, on driving behavior or signals from other control units, and a DC / AC inverter, which is used to supply electrical machines such as electric motors or generators with multi-phase alternating current (AC).In this process, a direct current generated by a DC energy source, such as a battery or accumulator, is converted into a multiphase alternating current. For this purpose, the inverters comprise a variety of electronic components that create bridge circuits (e.g., half-bridges), such as semiconductor power switches, also known as power semiconductors. A DC / DC converter may also be present in the power electronics.

[0003] Since one goal is to build electrically powered vehicles as light as possible, for example to enable the longest possible range, one goal of the invention is to provide a reduction in weight in the area of ​​the inverter and its components.

[0004] This problem is solved by the features of the independent claims. Advantageous embodiments are the subject of the dependent claims.

[0005] The invention relates to a base plate of a single-phase or multi-phase module of an inverter of an electric drive of an at least partially electrically powered vehicle for providing a liquid cooler in conjunction with a cooler housing, wherein the base plate is formed from at least two subassemblies, of which a first subassembly is formed as a basic structure, preferably in a lightweight construction, and a second subassembly is formed as at least one heat-conducting element received in the basic structure, which has one or more receiving areas for fastening a respective semiconductor package on an upper side and a cooling structure on a lower side opposite the upper side, wherein the cooling structure is arranged at least in the area of ​​the receiving area or areas, wherein the first subassembly and the second subassembly are firmly and liquid-tightly connected to one another.

[0006] In one embodiment, the heat-conducting element(s) are formed as a continuous structure or as several individual structures arranged next to one another.

[0007] The base plate particularly advantageously forms a closed structure. The heat-conducting elements are arranged or received on the base structure in such a way that the base structure has a closed structure, preferably being designed to be liquid-tight and / or gas-tight. A semiconductor package is advantageously arranged or fastened on the base plate, for example on a heat-conducting element. The semiconductor package is preferably fastened to the base plate, in particular to the heat-conducting element, via a soldered connection or a sintered connection. The base plate preferably serves as a cover and, together with a housing, provides a cooler. The base plate is advantageously sealed in a fluid-tight and / or gas-tight manner with respect to the housing. The housing is formed, for example, by a housing of the inverter or by a separate housing.The cooler is particularly advantageously an active liquid cooler, through which a cooling liquid, such as water or a water-antifreeze mixture, such as a water-glycol mixture, flows. The cooling liquid absorbs the heat generated in the semiconductor packages and dissipates it. Advantageously, the cooler has an inlet and an outlet that allow the cooling liquid to flow into and out of a cooling channel. The cooling channel is advantageously formed by the base plate and the housing.

[0008] The base plate is suitable for providing a liquid cooler. The multi-part base plate is designed to be liquid-tight. Preferably, the attachment between a heat-conducting element and the base structure is formed by a liquid-tight connection, preferably a material bond.

[0009] The base plate is advantageously flat or has a flat structure. A flat structure is characterized by a low thickness or material thickness, which contrasts with a comparatively large length and width. The multi-part base plate is advantageously formed from sheet metal. The material thickness of the heat-conducting element is preferably greater than, equal to, or less than the material thickness of the base structure. The material thickness of the heat-conducting element is advantageously determined exclusively by the thickness of the back plate, i.e., without cooling structures such as pin fins.

[0010] A surface of the heat-conducting element is preferably formed flat with a surface of the base structure or has, at least partially, a raised surface relative to the heat-conducting element.

[0011] The base structure advantageously has an increased material thickness in an area surrounding the heat-conducting element. Such an increased material thickness enables a force-fitting and particularly stable connection between the heat-conducting element and the base structure. The base structure and the heat-conducting element are advantageously connected to one another in such a connection area via soft soldering, brazing, or welding.

[0012] Advantageously, a heat-conducting element comprising a back plate and cooling structures is formed in one piece, wherein the cooling structures are provided by scraping or peeling from a blank.

[0013] Advantageously, a heat-conducting element comprising a backplate and cooling structures is provided in multiple parts, wherein the cooling structures are preferably pressed or soldered onto the backplate. The cooling structures are preferably arranged in grooves or recesses in the backplate. The heat-conducting structures are preferably plate-shaped, wherein this plate shape can be flat or wave-shaped, for example.

[0014] In one embodiment, the base structure is made of steel, aluminum or a plastic with a given specific density, and the heat conducting element(s) are made of copper or aluminum.

[0015] In one embodiment, the heat conducting element(s) and the base structure are connected to each other by means of a material-locking or frictional connection and are gas-tight.

[0016] In one embodiment, the heat conducting element(s) and the base structure are connected to each other by butt jointing or by means of a lap joint.

[0017] In one embodiment, the base structure in the region in which a heat-conducting element is provided has an undercut on at least two mutually opposite regions as a connecting region, wherein the heat-conducting element has supports corresponding to the undercuts as a connecting region such that, after assembly, it rests against the undercuts of the base structure from an underside of the base plate, and the supports and the undercuts are connected to one another.

[0018] In one embodiment, the base structure has, in the region in which a heat-conducting element is provided, a support on at least two mutually opposite regions as a connecting region, wherein the heat-conducting element has undercuts corresponding to the supports as a connecting region such that, after assembly, it rests from an upper side of the base plate on the supports of the base structure, and the undercuts and the supports are connected to one another.

[0019] In one embodiment, the base structure and the heat-conducting element are connected by means of a tongue and groove connection as connecting regions, wherein either the base structure has a groove and the heat-conducting element has a tongue, or wherein the base structure has a tongue and the heat-conducting element has a groove.

[0020] In one embodiment, the connecting regions of the heat-conducting element and the base structure are formed such that the region of the connecting regions of a heat-conducting element on the underside of the base plate extends from the cooling structure in a predetermined length in the direction of the base structure.

[0021] Particularly advantageously, the connection areas, undercuts, or supports of the aforementioned connection variants are formed over the entire circumference of the respective base structure receptacle and / or the respective heat-conducting element. This creates a self-contained connection area that provides optimal sealing, preferably gas- and / or liquid-tight, and optimal fastening between the heat-conducting element and the base structure.

[0022] In one embodiment, the heat conducting element(s) are formed such that they are flush with the base structure or protrude above the base structure by a predetermined height.

[0023] Furthermore, a cooler is proposed. The cooler serves to transfer heat to a cooling fluid flowing through the cooler and comprises at least one base plate according to one of claims 1 to 9 or one of the embodiments in this document and a cooler housing, wherein the at least one base plate and the cooler housing are firmly and fluid-tightly connected to one another.

[0024] Furthermore, a single-phase module or a multi-phase module is proposed, comprising the base plate, and at least one half-bridge arranged on the base plate and per phase, which half-bridge is formed from at least two semiconductor packages, which are preferably fastened to two heat-conducting elements arranged opposite one another, or which is formed as at least one semiconductor package, which is preferably fastened to a respective heat-conducting element, and DC and AC busbars arranged in a stacked manner on the half-bridge(s) and with the associated power connections.

[0025] Furthermore, power electronics for operating a three-phase electric motor of a vehicle are proposed, wherein the power electronics comprises an inverter formed from a multi-phase module or from a single-phase module for each phase, as well as at least one ECU connected to the electric motor for its control and regulation and to the inverter.

[0026] Furthermore, an electric drive of a vehicle is proposed, comprising a three-phase electric motor and a battery, as well as the power electronics connected to both.

[0027] Furthermore, a vehicle is proposed, comprising the electric drive, which is formed as an electric axle drive.

[0028] Further features and advantages of the invention will become apparent from the following description of exemplary embodiments of the invention, with reference to the figures of the drawing, which illustrate details of the invention, and from the claims. The individual features can be implemented individually or in combination in a variant of the invention.

[0029] Preferred embodiments of the invention are explained in more detail below with reference to the attached figures. Fig. 1 shows a sectional view of a basic arrangement of semiconductor package and base plate according to the prior art. Fig. 2 shows a plan view of a single-phase module equipped with semiconductor packages according to the prior art. Fig. 3 shows an oblique plan view of a base plate according to an embodiment of the present invention. Fig. 4 shows a sectional view of the Fig. 3 shown base plate. Fig. 5 shows a plan view of a base plate according to another embodiment of the present invention. Fig. 6 shows a sectional view of the Fig. Base plate shown in Figure 5. Fig. 7 shows a plan view of a base plate according to another embodiment of the present invention. Fig. 8 shows a sectional view of the Fig. Base plate shown in Figure 7. Fig. 9 to 12 show sectional views of a base plate according to further embodiments of the present invention. Fig. 13 another variant of a base plate in cross section. Fig. 14 a design variant for a cooler with several base plates. Fig. 15 to 18 a base plate with several heat conducting elements intended for several power modules.

[0030] In the following descriptions of the figures, the same elements or functions are provided with the same reference symbols.

[0031] Current single phase modules 1, as in Fig. 1, a schematic structure is shown for a part, on which a semiconductor package 4 is arranged, are characterized by the fact that the switching semiconductors 40 must be actively cooled in order to dissipate the switching and conduction losses. To dissipate the losses, a heat conduction path is constructed from the semiconductor 40 into a cooling medium 3, which is characterized by the fact that the thermal resistance should be as low as possible. The thermal path (resistors are shown on the far right) is usually constructed from the Fig. 1 comprises the components copper 41, ceramic 42, copper 41, base plate 2, and cooling medium 3. The circuit board formed from the layers of copper 41, followed by ceramic 42, followed by copper 41, represents an electrically insulating layer. Such a circuit board can be, for example, a DBC or an AMB circuit board.

[0032] Currently, base plates 2, also called cooling plates, are designed with a large surface area, as in Fig. 2, so that they also have sealing and mounting elements, such as screw holes 24 for fastening in the inverter housing. For optimal cooling, the base plates 2 are often made of copper, so that the areas not directly to be cooled are also made of copper. This results in a relatively high weight of the component (the base plate 2), which contradicts the current lightweight construction requirements in vehicle construction and consumes costs and resources. In order to make inverters (DC / AC inverters) in vehicles lighter, it is proposed to modify the structure of base plate 2 as described below. The goal is to provide the most optimal cooling possible for the semiconductors 40 (power semiconductors) of semiconductor packages 1 placed on base plate 2, more precisely, the designated receiving areas 22 (arranged in housing 43), while still achieving a lower weight than previously possible.

[0033] This is achieved by dividing the base plate 2 into two interconnected subassemblies, as shown Fig. 3. A first subassembly is formed as a base structure 20 in lightweight construction, and a second subassembly is formed as at least one heat-conducting element 21 integrated into the base structure 20 with one or more receiving regions 22 for the semiconductor packages 4. Depending on the design of the semiconductor packages 4, only one heat-conducting element 21 is present or there are two or more heat-conducting elements 21. If multiple heat-conducting elements 21 are provided, they lie opposite one another at a distance on the same side (e.g., the top side O) of the base structure 20. In principle, a heat-conducting element 21 is provided below each semiconductor package 4.

[0034] In an inverter, for example, half bridges are installed, each having a high-side switch and a low-side switch, which are arranged on one or more corresponding heat-conducting elements 21, in particular opposite one another, as shown in Fig. 3 shown. In Fig. 2, individual switches (lowside and highside) formed as semiconductor packages 4 can be seen. In an embodiment not shown in the figures, however, half-bridge modules can also be provided as semiconductor packages 4, in which at least one high-side and one low-side switch are already provided in a single package, which is then referred to as semiconductor package 4. These half-bridge modules are then arranged on a single heat-conducting element 21, which represents the second subassembly. Essentially, the first subassembly, i.e. the base structure 20, is a lightweight structure made of a material with a low specific density, e.g., aluminum or a plastic. When selecting the material, it is of course important to ensure that the necessary stability for application in the automotive sector is present, and that connection to other components of the inverter is as simple as possible. This means that, for example,screw holes 24 can also be provided.

[0035] The second subassembly, i.e. the heat conducting element(s) 21, are essentially manufactured as insert elements (inlets) designed in different configurations for the semiconductor packages 4. These insert elements have an optimized cooling structure 23, e.g. via pinfins, as shown in Fig. 4, 6, 8, and 9-12. Other structures such as meanders, bionic-inspired designs, etc. are also possible. The material for the cooling structure 23 is intended for maximized heat conduction and is therefore preferably made of copper, alternatively aluminum or another heat-conducting material. The material can also be coated. After installation in the inverter housing, the cooling structure 23 is immersed in a cooling medium 3 for improved heat dissipation, as shown in Fig. 1. The cooling medium is preferably a liquid, for example water or a water-antifreeze mixture, for example a water-glycol mixture.

[0036] In Fig. 3-6 show two embodiments in which the semiconductor packages 4 can be formed as individual switches. A semiconductor package 4 is preferably arranged on a respective heat-conducting element 21. In this embodiment, the heat-conducting element(s) 21 are each formed as a continuous structure, on which a plurality of receiving regions 22 for a respective semiconductor package 4 are provided next to and adjacent to one another. The receiving regions 22 are formed on the upper side O of the base plate 2. On the underside U of the base plate, the cooling structure 23 is provided on the respective heat-conducting element 21, as can be clearly seen in the sectional view in Fig. 4 and Fig. 6. The connection between the first and second subassembly, i.e. heat conducting element 21 and base structure 20, of the embodiments according to the Fig. 3 / 4 and 5 / 6 can be done in different ways, as shown below using the example of Fig. 9 to 12 described.

[0037] In Fig. 7 and Fig. Figure 8 shows a further alternative embodiment suitable for semiconductor packages 4 in the form of individual switches. Preferably, a semiconductor package 4 is arranged on a respective heat-conducting element. The heat-conducting elements 21 are formed by several individual components arranged adjacent to one another and spaced apart. The base structure 20 is provided between adjacent heat-conducting elements 21, i.e., in the spaced area, which can save weight or increase stability. In this embodiment, each heat-conducting element 21 has its own cooling structure 23.This design provides a production-technical advantage since the heat-conducting elements 21 can be manufactured as individual components and thus only a single tool is required, whereas in the case of the heat-conducting elements 21 formed as a continuous structure, a new tool must also be used if the number of receiving areas 22 is changed.

[0038] In the proposed concept, connecting the materials of the two subassemblies presents a challenge. The connection between the base structure 20 and the heat-conducting element(s) 21 (only the plural is used below) must (depending on the specific application) withstand the respective temperature, pressure, and tightness requirements, as well as take into account the manufacturing process and the subsequent steps. The connection between the base plate 20 and the heat-conducting element is therefore preferably achieved by a material-to-material, liquid-tight, and / or gas-tight connection, e.g., by welding, soldering, gluing, or even a frictional connection.

[0039] As described in Fig. As shown in Figure 4 and designated by reference symbol V1, the subassemblies, i.e., the base structure 20 and the heat-conducting elements 21, can be connected to one another by butting against each other on all side areas of the heat-conducting elements 21. Care must be taken to ensure that a very strong connection is created that is resistant to forces acting from the underside U and the top side O.

[0040] As described in Fig. 6 and Fig. 8 and designated by reference symbol V2, the subassemblies, i.e. the base structure 20 and the heat-conducting elements 21, can be connected to one another by means of a lap joint on all side areas of the heat-conducting elements 21. This means that in this case, the heat-conducting elements 21 have a projection on the side areas, where no cooling structure is provided on the underside, and with which they rest on the base structure 20. The advantage here is that the heat-conducting elements 21 already protrude above the base structure 20 by a height H due to the lap joint, as is also the case in the Fig. 9 to 12, and thus any required air gaps can be directly maintained. The heat-conducting elements 21 according to this connection type V2 can be designed with a smooth surface, preferably without any raised areas. In this design, too, care must be taken to create a very strong connection that is resistant to forces acting from the underside U and the top side O.

[0041] The connection of the two subassemblies can also be achieved, for example, by inserting the heat-conducting elements 21 into a tool and then overmolding or casting the base structure 20 if the material is an injection-moldable or castable material. This is, for example, the case in Fig. 7 and Fig. 8 or the Fig. The version shown in 9 to 12 is a possible option for production.

[0042] As in the Fig. 9-12, the subassemblies, i.e. the base structure 20 and the heat conducting elements 21, can be connected by means of corresponding interlocking structures.

[0043] In the Fig. In the embodiment shown in Figure 9, the base structure 20 has an undercut 200, and the heat-conducting elements 21 have a support 211 as a counterstructure. The undercut 200 is formed on an upper side of the base structure 20. In order to bring the two subassemblies together, i.e. to connect them to one another, the heat-conducting elements 21 are brought from the underside U of the base plate 2 into the recess provided therein until the support 211 rests against the undercut 200 and can be connected thereto. The semiconductor packages 4 can then be applied to the recesses 22 and fastened thereto. The connection between the base structure 20 and the heat-conducting elements 21 is created, for example, by a temperature-resistant process, e.g., brazing with high-temperature solder.By selecting such a robust fastening method, a subsequent fastening process for fastening the semiconductor packages 4 to the receiving areas 22, for example a soldering or sintering process, also allows the existing connections of the base plate 2 to survive undamaged. The advantage of this design is that it is self-locking against pressure from the underside U, which can be exerted, for example, by the cooling medium 23. The length of the support 211 must be selected at least such that the support 211 does not tear off the undercut 200 under a (maximum specified) pressure from the underside U. In a further design, the length (in the X direction) of the support 211 is selected to be longer than the minimum necessary in order to provide an enlarged cooling surface. The length depends on the required additional cooling.

[0044] In the Fig. In the embodiment shown in Figure 10, the base structure 20 has a support 201, and the heat-conducting elements 21 have an undercut 210 as a counterstructure. The support 201 is formed on an underside of the base structure 20. In order to bring the two subassemblies together, i.e., to connect them to one another, the heat-conducting elements 21 are brought from the top side O of the base plate 2 into the recess provided therein until the support 201 rests against the undercut 210 and can be connected thereto. In this embodiment, the semiconductor packages 4 can be applied to the recesses 22 in advance and fastened thereto. This reduces the thermal requirements for the connection point, since it only has to withstand the operating parameters. An advantage of this embodiment is that it is self-locking against pressure from the top side O.The length of the support 201 must be selected at least such that the support 201 does not tear off the undercut 210 under a (maximum predetermined) pressure from the upper side O. In a further embodiment, the region B of the heat-conducting element 21 between the end (in the X direction) of the undercut 210 and the beginning of the cooling structure 23 can be extended in the direction of the base structure 20 in order to provide an enlarged cooling surface, as in . Fig. 11. This means that the base structure 20 has a larger recess to accommodate the heat-conducting element 21. The length depends on the required additional cooling.

[0045] In the Fig. In the embodiment shown in Figure 12, the base structure 20 and the heat-conducting element 21 are connected by means of a tongue and groove connection as connecting areas. This can be done either as shown in Fig. 12, the base structure 20 has a groove 202 and the heat-conducting element 21 has a tongue 212. Alternatively, the base structure 20 has a tongue and the heat-conducting element 21 has a groove (not shown). Expediently, in this embodiment too, the base structure 2 is injection-molded or cast around the heat-conducting elements 21. It can also be provided that the base structure 20 is formed in two parts and is pushed onto the heat-conducting elements 21. The advantage of this embodiment is that it is self-locking against pressure from the underside U and also from the top side O, as well as against shear forces. In this embodiment too, the region B can be extended (in the direction of the base structure 20, i.e. X-direction) in order to provide an enlarged cooling surface. The length depends on the additional cooling required.

[0046] The joining processes described can be supported by coatings or surface structuring (ordered or disordered) of the joining surfaces.

[0047] As already described in connection with the individual figures, the edge areas of the heat-conducting elements 21 can be varied in size depending on the requirements. For example, by increasing the support area, more solder can be applied for the connection. By widening the cooling medium side (bottom side U) (extension in the X direction), the heat transfer can be increased.

[0048] In order to maintain specified air gaps between the busbars arranged above the base structure 20 (HV level) and the base structure 20 (GND level), the spacing, materials, and shape of the heat-conducting elements 21 must be selected accordingly. In one embodiment, the heat-conducting elements 21 are formed such that they are flush with the base structure 20. In an alternative embodiment, the heat-conducting elements 21 are formed such that they protrude above the base structure 20 by a specified height H.

[0049] Furthermore, suitable shapes may be arranged on or formed in the base structure 20 to stiffen the base structure 20, such as a rib structure.

[0050] The proposed base plate 2 is preferably used in single-phase modules 1 used in an inverter as a support and cooling plate, in order to be connected to a housing of the inverter on its underside U, provided with the cooling structure 23, and to support further components of the inverter, such as AC and DC busbars, as well as circuit boards and other components, on its upper side O (more precisely, the semiconductor packages 4 arranged thereon). Single-phase modules 1 are modules that each represent one phase of an inverter and can be connected to one another to form a multi-phase module. The base plate 2 can of course also be used for multi-phase modules, in which several phases of the inverter are realized on one base plate 2.

[0051] As already described, the base plate 2 serves as a carrier plate. Areas where no semiconductor packages 4 to be cooled are arranged are formed in a lightweight construction from a material sufficiently stable for the respective application, such as aluminum or plastic. Furthermore, the areas where the semiconductor packages 4 are arranged must have good thermal conductivity in order to be able to cool the semiconductors 40 provided therein. For this purpose, this part of the base plate 2 is designed as a heat-conducting element 21 and is made of a material such as copper. This provides sufficient heat dissipation for the semiconductor packages 4. The base plate 2 advantageously provides ground potential GND.

[0052] The semiconductor packages 4 are generally arranged opposite one another so that two of them form a half-bridge, with one semiconductor package 4 serving as a high-side switch and the other as a low-side switch, each of which can have power semiconductors connected in parallel, e.g. MOSFETs, IGBTs, etc. One or more half-bridges can be provided per phase. DC and AC power rails are preferably arranged above the half-bridges and electrically contacted with the associated power connections of the half-bridges. The term semiconductor package 4 refers to one or more encased (in a housing) power semiconductors (chips), which serve as high-side or low-side switches, including (unencased) connection legs for electrical or signal contact.The term semiconductor package 4 also refers to a half-bridge module in which high-side and low-side switches are already installed together in one housing.

[0053] Furthermore, a single-phase module 1 with a base plate 2 and at least two opposing semiconductor packages 4 forming a half-bridge is proposed. One of the semiconductor packages 4 is designed as a high-side switch and the other as a low-side switch. Furthermore, a multi-phase module is proposed, which differs from the single-phase module 1 only in that the base plate 2 is not used for just one phase of the inverter, but several, in particular three, phases are provided on a single base plate 2. For example, a three-phase module can be manufactured with only one base plate 2 instead of arranging three single-phase modules 1 together (next to one another).

[0054] The number of half-bridges depends on the required power of the inverter and the semiconductor packages used 4.

[0055] The base plate is advantageously used in power electronics, which is preferably used in an electric drive of a vehicle having a three-phase electric motor and a storage battery. The power electronics has an inverter with multiple phases and is connected to the electric motor and storage battery in order to generate direct current received from the storage battery into alternating current usable by the electric motor by means of the inverter in order to drive the electric motor. In an alternative operating mode, energy generated by the electric motor is stored in the storage battery. An ECU, i.e. an electronic control unit, is provided to control the inverter. The ECU is connected to the electric motor for its control and regulation and to the inverter. The electric motor is in particular an electric axle drive.

[0056] A vehicle, e.g. a passenger car or a commercial vehicle, advantageously has at least one such drive. The vehicle is in particular a commercial vehicle such as a truck or a bus, or a passenger car. The power electronics module (i.e. the power electronics) comprises a DC / AC inverter with the described structure. It can also comprise or be a part of an AC / DC rectifier, a DC / DC converter, a transformer and / or another electrical converter or a part of such a converter. In particular, the power electronics module is used to supply current to an electric machine, e.g. an electric motor and / or a generator. A DC / AC inverter is preferably used to generate a multi-phase alternating current from a direct current generated by means of a DC voltage from an energy source, e.g. a battery.

[0057] Further embodiments are described in the following figures.

[0058] In Fig. 13 shows another base plate 2 with a base structure 20 and a heat-conducting element 21. Only a single heat-conducting element is shown as an example, but additional heat-conducting elements 21 may also be formed.

[0059] The base plate 2 has a wall section 203 in its end region, which extends perpendicular to the main body 204. The wall section 203 provides a lateral boundary for the cooling channel 5. In this exemplary embodiment, the wall section also serves to arrange and fasten a cover 6, which closes off the cooling channel. The cover is firmly and fluid-tightly connected to the base plate 20, for example, via laser welding. A cooling fluid, for example water, a water-glycol mixture, or a water-antifreeze mixture, flows into the cooling channel via an inlet (not shown), flows through it, and flows out again via an outlet (not shown). The cover 6 can be regarded, for example, as a radiator housing.

[0060] The heat-conducting element 21, in particular its back plate, has a greater material thickness than the base structure 20. In a surrounding area around the receiving area 22 or around the heat-conducting element 21, the material thickness of the base structure is increased, this area being referred to below as the receiving section 205. A step 213 is formed on the heat-conducting element 21. A step 206 is formed on the base structure 20. The steps can fulfill different or multiple functions. Advantageously, the steps 213 and 206 are each formed circumferentially on the heat-conducting element 21 or the receiving area 22 and / or correspond to one another. For example, the steps serve to enable simple and precisely positioned insertion of the heat-conducting element 21 into the base structure 20 during a manufacturing process. Alternatively or additionally, the steps serve to provide a separate seal between the base structure 20 and the heat-conducting element.The seal is formed, for example, by a molded seal or a liquid seal. The seal is advantageously liquid-tight. Particularly advantageously, the heat-conducting element 21 is pressed, embossed, punched, or glued within the receiving section 205 or sections 205. Alternatively, the heat-conducting element 21 is soft-soldered, hard-soldered, or welded, in particular laser-welded, to the base plate, in particular to the receiving section(s) 205. With a liquid-tight joining process, the separate seal can optionally be omitted.

[0061] For example, manufacturing can be carried out by first performing a sealing process followed by a joining process. Alternatively, the joining process alone is sufficient, provided it creates a fluid-tight connection.

[0062] The heat-conducting element is preferably made of copper. The base structure is preferably made of aluminum or steel. The cover is preferably made of aluminum or steel. Steel is advantageously coated with a corrosion-protective coating, nickel-plated, or made of a corrosion-resistant steel, such as chromium-nickel steel.

[0063] In Fig. 14 shows a further embodiment variant. This comprises a cooler housing 7, which accommodates a base plate 2, in this case even three base plates 2. The base plates 2 are designed, for example, according to the previous embodiments. In particular, the base plates 2 have several, in this case two, heat-conducting elements 21. The base plates 2 are designed, for example, identical to one another. In particular, the base plates 2 are connected to the cooler housing 7 via welding, in particular laser welding, and are simultaneously sealed. In principle, the connection between the base body 7 and the base plate 2 can be designed in a manner comparable to one of the explained variants for providing a connection between the base structure 20 and the heat-conducting element 21. Fig. The cooler shown in Figure 14 provides a compact and lightweight design, while at the same time providing high rigidity and ensuring a space-saving and close arrangement of power modules.

[0064] Another version is in the Fig. 15 to 18. The base plate 2 comprises a base structure 20 for accommodating three heat-conducting elements 21, each of which is designed to accommodate multiple power modules. The heat-conducting elements 21 are made of copper, and the base structure is made of aluminum. Fig. 15 shows a top view of the base plate 2, Fig. 16 a heat conducting element 21, Fig. 17 a cross-section of the base plate and Fig. 18 the connection area between base structure 20 and heat conducting element 21. List of reference symbols 1 single-phase module 2 base plate 20 Basic structure 200 undercut 201 edition 202 groove 203 wall section 204 basic bodies 205 Recording section 206 Level 21 Heat conducting element 210 undercut of 21 211 edition of 21 212 spring 213 Level 22 Recording area for 4 23 Cooling structure (pinfins etc.) 24 screw holes 3 Cooling medium 4 Semiconductor package 40 semiconductors 41 copper 42 Ceramics 43 housings 5 cooling channel 6 lids 7 Radiator housing U Bottom of base plate O Top of base plate B Area between the end of 201 and the beginning of 23 H Height V1 blunt collision of 20 and 21 V2 lap joint between 20 and 21

Claims

[1] Base plate (2) of a single-phase or multi-phase module (1) of an inverter of an electric drive of an at least partially electrically driven vehicle for providing a liquid cooler in conjunction with a cooler housing, wherein the base plate (2) is formed from at least two subassemblies (20, 21), of which - a first subassembly is formed as a basic structure (20), preferably in lightweight construction, and - a second subassembly is formed as at least one heat-conducting element (21) received in the base structure (20), which has one or more receiving regions (22) for fastening a respective semiconductor package (4) on an upper side (O) and a cooling structure (23) on an underside (U) opposite the upper side (O), wherein the cooling structure (23) is arranged at least in the region of the receiving region(s) (22), wherein the first subassembly and the second subassembly are firmly and liquid-tightly connected to one another. [2] Base plate (2) according to claim 1, wherein the heat conducting element(s) (21) - are formed as a continuous structure, or - as several individual structures arranged next to each other are formed. [3] Base plate (2) according to one of the preceding claims, wherein the base structure (20) is formed from steel, aluminum or a plastic with a predetermined specific density, and wherein the heat conducting element(s) (21) is formed from copper or aluminum. [4] Base plate (2) according to one of the preceding claims, wherein the heat conducting element(s) (21) and the base structure (20) are connected to one another by means of a materially bonded or frictionally bonded connection and in a gas-tight manner. [5] Base plate (2) according to one of the preceding claims, wherein the heat conducting element(s) (21) and the base structure (20) - are connected by blunt abutment (V1), or - are connected to each other by means of a lap joint (V2). [6] Base plate (2) according to one of claims 1 to 4, wherein the base structure (20) in the region in which a heat conducting element (21) is provided, - has an undercut (200) on at least two mutually opposite regions as a connecting region, wherein the heat-conducting element (21) has supports (211) corresponding to the undercuts (200) as a connecting region such that, after assembly, it rests on the undercuts (200) of the base structure (20) from a lower side (U) of the base plate (2), and the supports (211) and the undercuts (200) are connected to one another, or - a support (201) on at least two mutually opposite regions as a connecting region, wherein the heat-conducting element (21) has undercuts (210) corresponding to the supports (201) as a connecting region such that, after assembly from an upper side (O) of the base plate (2), it rests on the supports (201) of the base structure (20), and the undercuts (210) and the supports (201) are connected to one another. [7] Base plate (2) according to one of the preceding claims, wherein the base structure (20) and the heat-conducting element (21) are connected by means of a tongue and groove connection as connecting regions, wherein either the base structure (20) has a groove (202) and the heat-conducting element (21) has a tongue (212), or wherein the base structure (20) has a tongue and the heat-conducting element (21) has a groove. [8] Base plate (2) according to claim 6 or 7, wherein the connecting regions of the heat-conducting element (21) and the base structure (20) are formed such that the region of the connecting regions of a heat-conducting element (21) on the underside (U) of the base plate (2) extends from the cooling structure (23) in a predetermined length in the direction of the base structure (20). [9] Base plate (2) according to one of the preceding claims, wherein the heat conducting element(s) (21) are formed such that they are flush with the base structure (20) or project beyond the base structure (20) by a predetermined height (H). [10] Cooler (7) for dissipating heat to a cooling liquid flowing through the cooler (7), comprising at least one base plate (2) according to one of the preceding claims and a cooler housing (6; 7), wherein the at least one base plate (2) and the cooler housing (6; 7) are firmly and liquid-tightly connected to one another. [11] Single-phase module (1) or multi-phase module, comprising a base plate (2) according to one of the preceding claims, and - at least one half-bridge arranged on the base plate (2) and per phase, which is formed from at least two semiconductor packages (4), which are preferably fastened to two heat-conducting elements (21) arranged opposite one another, or which is formed as at least one semiconductor package (4), which is preferably fastened to a respective heat-conducting element (21), and - DC and AC busbars electrically contacted and stacked on the half-bridge(s) and with the associated power connections. [12] Power electronics for operating a three-phase electric motor of a vehicle, the power electronics comprising: - an inverter formed from a multi-phase module according to claim 11 or, per phase, from a single-phase module (1) according to claim 11, and - at least one ECU connected to the electric motor for its control and regulation and to the inverter. [13] Electric drive of a vehicle, comprising a three-phase electric motor and an accumulator, as well as power electronics connected to both according to claim 12. [14] Vehicle comprising an electric drive according to claim 13, which is formed as an electric axle drive.

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