Three-dimensional cooling structure for power semiconductors and methods for manufacturing them

Abstract

Three-dimensional cooling arrangement for power semiconductors, wherein a base heat sink (1) comprising a base plate (10) and at least one further heat sink (2) are provided, wherein each further heat sink (2) has a carrier plate (20) with a cooling structure (21) arranged on one or both sides thereof in a predetermined pattern, and wherein - in a first case, the base heat sink (1) has a cooling structure (11) arranged in a predetermined pattern on the base plate (10), and wherein the support plate (20) of a first heat sink (2) is arranged on the cooling structures (11) of the base heat sink (1) such that the cooling structure (11) of the base heat sink (1) and the cooling structure (20) of the first heat sink (2) point in the same direction and are arranged offset from each other such that the cooling structure (11) of the base heat sink (1) is arranged at the spaces between the cooling structure (20) of the first heat sink (2) and is connected there to the support plate (20), or - in a second case, the base heat sink (1) has a base plate (10) without a cooling structure with a predetermined length and width, wherein several further heat sinks (2) are provided, and wherein the length and / or width of the base heat sink (1) corresponds to a multiple of the length and / or width of one of the further heat sinks (2), and the further heat sinks (2) are arranged in series and / or matrix-like fashion on the base heat sink (1) such that they are arranged over its entire length and / or width, wherein top surfaces (211) of the cooling structures of the carrier plate (21) are connected to the base plate (11).

Description

[0001] The present invention relates to the field of electromobility, in particular electronic modules for an electric drive, specifically a cooling device for cooling heat-producing components.

[0002] The use of electronic modules, such as power electronic modules, in motor vehicles has increased significantly in recent decades. This is due, on the one hand, to the need to improve fuel efficiency and vehicle performance, and on the other hand, to advances in semiconductor technology. The main component of such an electronic module is a DC / AC inverter, which serves to supply electrical machines such as electric motors or generators with multiphase alternating current (AC). In this process, direct current generated by a DC energy source, such as a battery, is converted into multiphase alternating current. To this end, inverters comprise a variety of electronic components that implement bridge circuits (such as half-bridges), for example, semiconductor power switches, also known as power semiconductors.

[0003] Especially in the field of power electronics, it is necessary to dissipate heat from sensitive components. This is achieved using heat sinks. A problem with currently known heat sink manufacturing processes is that each method has its drawbacks. For example, additively manufactured heat sinks are too expensive and not fast enough for mass production. Sintered or forged heat sinks are also expensive, but also have limitations in their shape due to the tooling used. For instance, undercuts are not possible. Heat sinks manufactured by bending processes generally have low thermal conductivity and therefore low cooling capacity due to the limitations in material thickness. Cooling arrangements are disclosed, for example, in DE 10 2021 100 170 A1, JP 2013-165 122 A, and US 6 622 786 B1.

[0004] The invention thus aims to provide an improved three-dimensional cooling structure for power semiconductors and a method for manufacturing it. This objective is achieved by the features of the independent claims. Advantageous embodiments are the subject of the dependent claims.

[0005] A three-dimensional cooling arrangement for power semiconductors is proposed, comprising a base heat sink having a base plate, and at least one further heat sink, wherein each further heat sink has a carrier plate with a cooling structure arranged on one side thereof in a predetermined pattern, and wherein in a first case the base heat sink has a cooling structure arranged on the base plate in a predetermined pattern, and wherein the carrier plate of a first heat sink is arranged on the cooling structures of the base heat sink in such a way that the cooling structure of the base heat sink and the cooling structure of the first heat sink are arranged offset from each other in such a way that the cooling structure of the base heat sink is arranged at intervals of the cooling structure of the first heat sink and is connected there to the carrier plate.In a second case, the base heat sink has a predetermined length and width, and several other heat sinks are provided, wherein the length and / or width of the base heat sink corresponds to a multiple of the length and / or width of one of the other heat sinks, and the other heat sinks are arranged in series and / or matrix-like fashion on the base heat sink in such a way that they are arranged over its entire length and / or width, with the top surfaces of the cooling structures of the carrier plate being connected to the base plate.

[0006] In one embodiment, in the first case, the cooling structures of the first heat sink are shorter than the cooling structures of the base heat sink and point towards the base plate, and the cooling structures of the base heat sink are attached to the carrier plate of the first heat sink.

[0007] In one embodiment, in the first case, the top surfaces of the cooling structures are connected to the side of the carrier plate on which no cooling structures are present.

[0008] In one embodiment, in the first case, further heat sinks are stacked on top of each other above the first heat sink in such a way that all top surfaces of the cooling structures point in the same direction and the top surfaces of the cooling structures of a lower support plate are connected to the support plate above it.

[0009] In one embodiment, the additional heat sinks are formed in the same length and width as the first heat sink, and / or the cooling structures of the first and the additional heat sinks have the same height, and wherein the cooling structures of the first and the additional heat sinks are shorter or have the same height as the cooling structures of the base heat sink.

[0010] In one version, the upper surfaces of the cooling structures of the base plate and / or the carrier plate are joined by laser welding, soldering, sintering, or forging.

[0011] In one version, the cooling structures are formed as pins, pin fins, fins, or a combination thereof.

[0012] In one version, the thickness of the base plate is greater than the thickness of any support plate.

[0013] In one embodiment, the specified pattern of the base heat sink and the other heat sinks is such that the cooling structures arranged one above the other are offset from each other after assembly.

[0014] Furthermore, a method for manufacturing the three-dimensional cooling arrangement for the first case is provided, wherein in a preliminary process the base cooling body and at least one further cooling body are formed, and in a first step the first cooling body is connected to the base cooling body in such a way that the cooling structures of the base cooling body are arranged in an intermediate space between the cooling structures of the first cooling body and are connected to the carrier plate, and in an optional second step further cooling bodies are stacked on top of each other.

[0015] Furthermore, the use of the three-dimensional cooling arrangement for cooling power semiconductors of an inverter is proposed.

[0016] Furthermore, an electronic module for controlling the electric drive of a vehicle equipped with an electric drive is provided, comprising an inverter with power semiconductors, as well as the three-dimensional cooling arrangement for cooling the power semiconductors. Additionally, an electric drive of a vehicle, comprising an electronic module for controlling the electric drive, and a vehicle comprising the electric drive are provided.

[0017] 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 in the drawing, which shows details of the invention, and from the claims. The individual features can be implemented individually or in any combination in a variant of the invention.

[0018] Preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawing. Fig. Figure 1 shows a basic structure of a three-dimensional cooling structure produced by the proposed method according to an embodiment of the present invention. Fig. 2 shows the in Fig. 1 Three-dimensional cooling structure shown in exploded view, as well as the manufacturing sequence. Fig. Figure 3 shows a detailed view of a Fig. 2 shown connection surface 201. Fig. Figure 4 shows an exploded view of a basic structure of a three-dimensional cooling structure produced by the proposed method according to a further embodiment of the present invention. Fig. Figure 5 shows a basic structure of a three-dimensional cooling structure produced by the proposed method according to a further embodiment of the present invention. Fig. 6 and Fig. 7 show the assembly of the in Fig. 4 three-dimensional cooling structures shown.

[0019] In the following figure descriptions, identical elements or functions are marked with the same reference symbols.

[0020] As mentioned at the outset, currently available cooling structures have several disadvantages, depending on the manufacturing process. The aim of the invention is therefore to produce a three-dimensional cooling structure based on pin, pin-fin, or fin structures that can be manufactured using a mass-production-ready process and enables cost-effective and flexible production. Furthermore, the cooling structure should be so cost-optimized and flexible that small-batch production and prototype manufacturing are possible. This is achieved through a modular approach in which as many components as possible are formed identically, as described below. Another objective is to increase the density of cooling structures per cooling surface with fewer restrictions on the fine contours in the die.

[0021] These objectives are achieved by mechanically and thermally connecting at least two heat sinks 1, 2 to form a three-dimensional cooling arrangement. Basically, one of the heat sinks 1 is designed as the base heat sink 1. In one embodiment, this can consist solely of a base plate 10, as shown in Fig. 4 shown. In further embodiments, it consists of a base plate 10 with a cooling structure 11 arranged on one side of it.

[0022] Each additional heat sink 2 has a carrier plate 20 and a cooling structure 21 arranged on one side thereof. The cooling structure 21 can be located on both sides of the carrier plate 20.

[0023] The cooling structures 11, 21 are attached to the base plate 10 or carrier plate 21 with an end region thereof, in particular formed directly from it, and have a top surface 111, 211 on the opposite side (i.e. the side which is turned away from the base plate 10 or carrier plate 21).

[0024] The cooling structures 11, 21 are furthermore arranged in a predetermined pattern on the base plate 10 or carrier plate 21, as described below with regard to the individual embodiments.

[0025] Each of the cooling structures 11, 21 can be formed as a pin, pin-fin, or fin structure. Advantageously, all components of a cooling arrangement have the same type of cooling structures 11, 21.

[0026] The following explanations are described with reference to the figures.

[0027] In Fig. 1 and Fig. Figure 2 describes an embodiment in which a base plate 10 is provided with a cooling structure 11 arranged on one side thereof. Two heat sinks 2 are arranged on this base plate, each consisting of a carrier plate 20 and a cooling structure 21 arranged on one side thereof, in order to create a three-dimensional cooling arrangement. The upper surfaces 111, 211 of the cooling structures 11, 211 point in the same direction.

[0028] The cooling structures 10, 20 are arranged in a predefined pattern on the base plate 10 and the support plates 2 and are implemented here as a pin-fin cooling structure. All patterns are identical. Advantageously, the pattern of the cooling structure 21 of the first support plate 20, which is arranged on the cooling structure 11 of the base plate 11, is offset from the patterns of the other cooling structures 11, 21 to enable the connection, as described below.

[0029] The connection between base heat sink 1 and heat sink 2, and between further heat sinks 2 themselves, is achieved by arranging them one above the other so that their patterns are offset from each other. This means that the top surface 111, 211 of a cooling structure 11, 21 is connected to a bottom surface of the associated carrier plate 20 (via a connection surface 201) in such a way that there is no cooling structure 11, 21 on the opposite side of the carrier plate 20. Thus, the cooling structures 11 of the base heat sink 1 are arranged in the spaces between the cooling structure 21, i.e., between pins, pin fins, or fins of the first heat sink 2. The connection surface 201 is described in detail in Fig. 3 shown.

[0030] The upper surface 111, 211 of the cooling structures 11, 21 is attached to the connecting surface 201 of the carrier plate 20 (on the side that does not have cooling structures 11, 21) by a suitable method. Laser welding is particularly suitable for this purpose. However, soldering, sintering, other welding processes, or forging are also conceivable. Depending on the shape of the cooling structures 11, 21, their entire upper surface 111, 211 can be attached to the carrier plate 20, or only parts of it.

[0031] The assembly of a three-dimensional cooling arrangement with multiple heat sinks 2 is advantageously carried out by arranging them one above the other in succession. First (step S1 in Fig. 2) A carrier plate 20 of a first heat sink 2 is attached to the top surface 111 of the cooling structure 11 of the base heat sink 1 as already described. In a further step (step S2 in Fig. 2) The next heat sink 2 is positioned and attached to the top surface 211 of the cooling structure 21 of the first heat sink 2 located below it. Further heat sinks 2 are successively applied to and attached to the heat sink 2 below them.

[0032] The in Fig. The design shown in 1-3 allows for better cooling on a smaller surface area due to the stacking of the heat sinks 2 (this corresponds at most to the area of ​​the base plate 10).

[0033] In the Fig. In the embodiment shown in Figure 4, the base heat sink 1 has only a base plate 10 of a predetermined length and width without any further cooling structures. Furthermore, several heat sinks 2 are provided, each with a carrier plate 20 and a cooling structure 21 arranged on one side thereof. In contrast to the embodiment shown in Figure 4, the base heat sink 1 has a base plate 10 of a predetermined length and width without any further cooling structures. Fig. In the embodiments shown in 1 to 3, the heat sinks 2 are arranged side by side (instead of one above the other) because the base plate 10 is a multiple of the length and / or width of the base plate 10. Fig. 1, Fig. 2 to Fig. 3 corresponds. In addition, in this version, the base plate 10 is applied to and attached to the top surface 211 of the cooling structures 21 of the heat sink 2. The attachment is also carried out, for example, by laser welding, forging, brazing, or sintering.

[0034] In this design, a large area can be covered without the need for the complex production of long heat sinks 2 with corresponding cooling structures 21. The heat sinks 2 can thus be optimized in size for production purposes and therefore mass-produced in a uniform manner. By arranging them side by side, a large (extra-large) area, especially one >300 mm in length, can still be covered. Furthermore, by a matrix-like arrangement, i.e., side by side in two directions, a wider area than previously possible can also be easily provided with cooling structures 21.

[0035] In the Fig. 5, Fig. 6 to Fig. The 7 shown versions are, as in the in Fig. In the embodiment shown in Figures 1-3, a base heat sink 1 with a base plate 10 and a cooling structure 11 arranged on one side thereof, and a heat sink 2 with a support plate 20 and a cooling structure 21 arranged on one side thereof are provided. These are not connected to each other in such a way that the upper surfaces 111, 211 of the cooling structures 11, 21 point in the same direction. Rather, they are connected such that their upper surfaces 111, 211 each point towards the base plate 10 and support plate 20, respectively, and thus each engage in the spaces between the cooling structures 11, 21. In this embodiment, it is also important that the patterns of the cooling structures 11, 21 are offset from each other so that the cooling structures 11, 21 can engage in the spaces between the cooling structures 11, 21. This is shown in Figure 1-3. Fig. 6 and Fig. 7 illustrated by the representation of a step-by-step assembly.

[0036] In this embodiment, the cooling structure 11 of the base heat sink 1 advantageously has a greater length than the cooling structure 21 of the heat sink 2. The upper surfaces 111 of the cooling structure 11 of the base heat sink 1 are attached to the carrier plate 20 by a suitable method, e.g., laser welding, forging, brazing, sintering, etc.

[0037] The minimum distance between the pins of the cooling structures 11, 21 is predetermined by production processes and can be reduced by nesting cooling structures 11, 21 of two heat sinks 1, 2. This allows for a higher pin density than previously possible.

[0038] The thickness of the base plate 10, 20 is greater than the thickness of the carrier plates 20 in all versions, but can also be the same thickness depending on the application.

[0039] The pattern of the cooling structures 11, 21 is advantageously the same. To obtain an offset pattern, the manufactured cooling elements 2 can, for example, be cut accordingly. Or they can be manufactured directly with two different arrangements (swapping the space around cooling structure 21) of the pattern.

[0040] The proposed three-dimensional cooling arrangement provides a modular cooling system, enabling a mass-production-ready manufacturing process and cost-effective production of the three-dimensional cooling arrangement based on pin, pin-fin, or fin structures. This allows for an increase in the fluid contact surface area per unit area while maintaining the existing mass-production-ready main manufacturing process (e.g., forging, extrusion, or sintering). Furthermore, a very good cooling-to-pressure-loss ratio can be achieved.

[0041] Furthermore, a more cost-optimized and flexible manufacturing process for 2D and 3D pin, pinfin, or fin cooling structures can be provided for smaller series production or prototype manufacturing by pursuing a common-part approach for the pinfin cooling structure (modularization), as described. This results in reduced tooling costs and greater flexibility in component size.

[0042] Furthermore, an increase in the pin, pin fin or fin density per cooler surface is possible with fewer restrictions on the fine contours in the tool die.

[0043] This means that larger PinFin components can be manufactured, as there is no restriction on the pressing force or the size of the presses or sintering furnaces.

[0044] The proposed three-dimensional cooling arrangement is advantageously used for cooling power semiconductors in electronic modules.

[0045] An electronic module within the scope of this invention serves to operate the electric drive of a vehicle, in particular an electric vehicle and / or a hybrid vehicle, and / or electrified axles. The electronic module comprises a DC / AC inverter. It may also include an AC / DC rectifier, a DC / DC converter, a transformer, and / or another electrical converter, or a part thereof. In particular, the electronic module serves to power an electric machine, for example, an electric motor and / or a generator. A DC / AC inverter preferably serves to generate a multiphase alternating current from a direct current generated by means of a DC voltage from an energy source, such as a battery.

[0046] Inverters for electric drives of vehicles, especially cars and trucks, as well as buses, are designed for the high-voltage range and are specifically designed in a blocking voltage class of approximately 650 volts and above. Reference symbol list 1 Base heat sink 10 Base plate 11 Cooling structure (PinFin) 111 Top side cooling structure 2 heat sinks 20 carrier plate(s) 201 Connecting surface 21 cooling structure(s) (PinFin) 211 Top side cooling structure S1, S2 assembly steps

Claims

[1] Three-dimensional cooling arrangement for power semiconductors, wherein a base heat sink (1) comprising a base plate (10) and at least one further heat sink (2) are provided, wherein each further heat sink (2) has a carrier plate (20) with a cooling structure (21) arranged on one or both sides thereof in a predetermined pattern, and wherein - in a first case, the base heat sink (1) has a cooling structure (11) arranged in a predetermined pattern on the base plate (10), and wherein the support plate (20) of a first heat sink (2) is arranged on the cooling structures (11) of the base heat sink (1) such that the cooling structure (11) of the base heat sink (1) and the cooling structure (20) of the first heat sink (2) point in the same direction and are arranged offset from each other such that the cooling structure (11) of the base heat sink (1) is arranged at intervals of the cooling structure (20) of the first heat sink (2) and is connected there to the support plate (20), or - in a second case, the base heat sink (1) has a base plate (10) without a cooling structure with a predetermined length and width, wherein several further heat sinks (2) are provided, and wherein the length and / or width of the base heat sink (1) corresponds to a multiple of the length and / or width of one of the further heat sinks (2), and the further heat sinks (2) are arranged in series and / or matrix-like fashion on the base heat sink (1) such that they are arranged over its entire length and / or width, wherein top surfaces (211) of the cooling structures of the carrier plate (21) are connected to the base plate (11). [2] Three-dimensional cooling arrangement according to claim 1, wherein in the first case top surfaces (111, 211) of the cooling structures (11, 21) are connected to the side of the support plate (20) on which no cooling structures (21) are present. [3] Three-dimensional cooling arrangement according to claim 1 or 2, wherein in the first case further cooling bodies (2) are stacked above the first cooling body (2) such that all top surfaces (111, 211) of the cooling structures (11, 21) point in the same direction and the top surfaces (111, 211) of the cooling structures (11, 21) of a lower support plate (20) are connected to the support plate (20) above it. [4] Three-dimensional cooling arrangement according to one of the preceding claims, wherein - the additional heat sinks (2) are formed in the same length and width as the first heat sink (2), and / or - the cooling structures (21) of the first and the further heat sinks (2) have the same height and wherein the cooling structures (21) of the first and the further heat sinks (2) are shorter or have the same height as the cooling structures (11) of the base heat sink (1). [5] Three-dimensional cooling arrangement according to one of the preceding claims, wherein the connection of the top surfaces (111, 211) of the cooling structures (11, 21) of the base plate (10) and / or the carrier plate (20) is carried out by laser welding or brazing or sintering or forging. [6] Three-dimensional cooling arrangement according to one of the preceding claims, wherein the cooling structures (11, 21) are formed as pins, pin fins, fins or a combination thereof. [7] Three-dimensional cooling arrangement according to one of the preceding claims, wherein the thickness of the base plate (10) is greater than or equal to the thickness of each support plate (20). [8] Three-dimensional cooling arrangement according to one of the preceding claims, wherein the predetermined pattern of the base heat sink (1) and the further heat sinks (2) is such that the cooling structures (11, 21) arranged one above the other are offset from each other after assembly. [9] Method for producing a three-dimensional cooling arrangement according to one of the preceding claims for the first case, wherein in a preliminary process the base cooling body (1) and at least one further cooling body (2) are formed, and in a first step (S1) the first cooling body (2) is connected to the base cooling body (1) such that the cooling structures (11) of the base cooling body (1) are arranged in an intermediate space between the cooling structures (21) of the first cooling body (2) and are connected to the carrier plate (20), and in an optional second step (S2) further cooling bodies (2) are stacked on top of each other. [10] Use of the three-dimensional cooling arrangement according to any one of claims 1 to 8 for cooling power semiconductors of an inverter. [11] Electronic module for controlling the electric drive of a vehicle equipped with an electric drive, comprising an inverter with power semiconductors, and the three-dimensional cooling arrangement according to one of claims 1 to 8 for cooling the power semiconductors. [12] Electric drive of a vehicle, comprising an electronic module according to claim 11 for controlling the electric drive. [13] Vehicle comprising an electric drive according to claim 12.

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