Cooling device

Abstract

The invention relates to a cooling device (1) for cooling components (2) comprising a base element (4) with a first surface (5) and a base element height (9), and a cooling structure with cooling elements (6) arranged on the base element (4) projecting beyond the first surface (5), wherein the cooling elements (6) have a cooling element height (8). The base element (4) has a varying base element height (9), and cooling elements (6) with varying cooling element heights (8) are arranged, wherein the sum of the base element height (9) and the cooling element height (8) is the same in all areas of the base element (4) in which cooling elements (6) are arranged.

Description

[0001] The invention relates to a cooling device for cooling components comprising a base element with a first surface and with a base element height, a cooling structure with cooling elements which is arranged on the base element projecting above the first surface, wherein the cooling elements have a cooling element height.

[0002] The invention further relates to a method for manufacturing a cooling device comprising the steps of manufacturing a base element with a first surface, manufacturing a cooling structure having cooling elements on the first surface of the base element, wherein the base element is manufactured with a base element height and the cooling elements are manufactured with a cooling element height.

[0003] So-called power electronics components, such as power semiconductors, are well known in the prior art. Such components are frequently used, for example, in motor vehicles. It is also known that these components generate significant amounts of heat during operation, which often needs to be dissipated using a cooling medium. Various coolers are known in the prior art for this purpose, including so-called pin-fin heat sinks, which are surrounded by a cooling medium and thus transfer the heat from the pins to the cooling medium. For example,DE 10 2019 108 106 A1 describes a cooler for a power semiconductor in an inverter, wherein the cooler is designed in two parts and comprises: a base plate as the first part, which can be thermally connected to the power semiconductor; a heat sink as the second part, which is arranged on the base plate, wherein the heat sink has at least one corrugated recess, which is continuous from a side of the heat sink facing away from the base plate to a side facing the heat sink; wherein the first and second parts are connected to each other and are coated by means of a layer that protects both parts from electrochemical reduction.

[0004] From DE 10 2018 216 859 A1, a device for cooling components is known, comprising: a first and a second base body; cylindrical and / or conical first cooling fins formed in the first base body, around which a coolant can flow, and cylindrical and / or conical second cooling fins formed in the second base body, around which the coolant can flow, wherein the second is joined to the first base body in such a way that the second cooling fins lie between the first cooling fins without touching the first base body.

[0005] AT 526 330 A4 describes a method for manufacturing a cooling device comprising the steps of providing a material and forming a cooling structure from the material, wherein a sintered powder is used as the material, from which a green body is produced by pressing, which is sintered to form a preform, and from the preform the cooling structure in the form of cooling elements is produced by forming, for which a part of the preform is pressed through a forming tool.

[0006] The present invention is based on the objective of providing a cooling device for components with improved cooling performance.

[0007] The object of the invention is achieved in the aforementioned cooling device by the fact that the base element has a varying base element height, and that further cooling elements with varying cooling element heights are arranged, wherein the sum of base element height and cooling element height is the same in all areas of the base element in which cooling elements are arranged.

[0008] Furthermore, the object of the invention is solved by the aforementioned method, in which the base element is manufactured with a varying base element height, and cooling elements with varying cooling element heights are manufactured, wherein the sum of base element height and cooling element height is the same in all areas of the base element in which cooling elements are arranged.

[0009] An advantage of this design is that by selectively reducing the base element height, the cooling effect of the cooling device can be improved by increasing the height of the cooling elements, without altering the overall height of the cooling device. The change in the ratio of cooling element height to base element height is implemented particularly in those areas designated for installation on a component to be cooled, thus increasing the heat flow in these areas. This area can be adapted accordingly, depending on the component to be cooled, i.e., in particular, the size of its contact surface. In addition to the improved cooling performance of the cooling device, the design according to the invention also reduces the resulting pressure loss in the cooling system. Furthermore, it also saves material in the manufacture of the cooling device.

[0010] Preferably, according to one embodiment of the invention, the base element may have at least one trough-shaped depression to reduce its height. This trough-shaped depression improves the directed flow of cooling fluid around the cooling elements arranged therein, extending to the connection area with the base element, thereby further improving the cooling efficiency of the cooling device.

[0011] To create better flow conditions for the cooling fluid, a further design variant may provide that the side surfaces of the trough-shaped depression are inclined to the horizontal.

[0012] Preferably, according to a further embodiment of the invention, cooling elements can also be arranged on the side surfaces that slope downwards from the horizontal. This makes it easier to form the slopes with a relatively shallow gradient, thus improving the design of the cooling device, particularly when it is preferably manufactured by material forming. The shallower gradient facilitates the demolding of the cooling device after forming in a mold. Furthermore, the arrangement of cooling elements on the sloped side surfaces does not reduce the cooling capacity of the cooling device.

[0013] According to another embodiment of the invention, the back side of the base element can be designed with a flat surface, which improves the contact of the base element with a die during forming and with a component to be cooled during operation of the cooling device. The improved contact with the die enables a more uniform forming process when viewed across the first surface of the cooling device where the cooling elements are formed. This, in turn, improves the process of forming cooling elements of varying heights through forming.

[0014] To further improve the aforementioned effects, in particular the cooling performance of the cooling device, according to one embodiment of the invention it may be provided that the base element height of the base element is reduced by at least 30% in areas with reduced base element height, relative to the maximum base element height of the base element.

[0015] Easier manufacturing of the cooling element can be achieved if the base element and the cooling elements are made of a sintered material.

[0016] As mentioned previously, the cooling elements can be manufactured by forming the same material as the base element. An advantage of this method is that forming the base element into the cooling elements generates no waste material, unlike machining processes. Furthermore, all cooling elements of the cooling device can be manufactured simultaneously, resulting in a significant increase in productivity.

[0017] According to one embodiment of the invention, at least one stiffening element can be arranged to increase the flexural strength of the base element. This stiffening element is preferably arranged on the first surface of the base element, where the cooling elements are also located. This achieves the additional effect of further improving the cooling performance of the cooling device with the stiffening element itself. Due to the increased flexural strength, the height of the base element can be further reduced, thereby allowing the height of the cooling elements to be further increased.

[0018] To better understand the invention, it is explained in more detail with reference to the following figures.

[0019] They each show, in simplified, schematic form: Fig. 1 a cooling device with component to be cooled in side view; Fig. 2 a cooling device in oblique view; Fig. 3 a variant of a preform; Fig. 4 a variant design of a tool for manufacturing the cooling device.

[0020] It should be noted at the outset that in the differently described embodiments, identical parts are provided with the same reference numerals or component designations, and the disclosures contained in the entire description can be applied analogously to identical parts with the same reference numerals or component designations. Furthermore, the positional designations chosen in the description, such as top, bottom, side, etc., refer to the figure directly described and illustrated, and these positional designations must be applied analogously to the new position if the position changes.

[0021] In Fig. Figure 1 shows a cooling device 1 in side view.

[0022] The cooling device 1 serves to cool one or more components 2 or an assembly. For this purpose, the cooling device 1 rests against at least one component 2 with a rear surface 3, preferably directly, thus being in direct contact with the component 2 for heat exchange. The component 2 can simply rest against the cooling device 1, i.e., without any further connection to it. However, the component 2 can also be connected to the cooling device 1, e.g., by gluing, screwing, soldering, sintering, etc.

[0023] Component 2 is preferably an electronic component, in particular a so-called power electronics component or high-performance electronics component, or a power semiconductor or high-performance semiconductor. In particular, such components 2 or assemblies made of / containing these components 2 can be designed for power outputs in the range of several kW up to MW. Such components 2 serve, for example, to convert electrical energy using switching electronic components. Typical applications include converters or frequency converters in the field of electrical drive technology, solar inverters and converters for wind turbines for feeding renewable energy into the grid, or switched-mode power supplies, generally the conversion of alternating current to direct current by rectifiers, the conversion of direct current to alternating current by inverters, and control systems, for example, in the drive technology of an electric drive in electric vehicles.Hybrid vehicles, battery management systems, etc. A power electronics component can be, for example, a semiconductor, in particular a so-called power semiconductor, e.g. an IGBT.

[0024] Since such components 2 are known in themselves from the relevant prior art, reference is made to this prior art with regard to details.

[0025] The cooling device 1 comprises a base element 4, which also forms the rear side 3 of the cooling device 1, and which has a cooling structure on a first surface 5, or consists of the base element 4 and the cooling structure. The cooling structure is formed by (or comprises) cooling elements 6, which are arranged projecting beyond the first surface 5 on the base element 4 and are thus preferably integrally connected, as is also shown in the figure. Fig. As can be seen in Figure 2. In other words, in the preferred embodiment, the cooling device 1 is formed by only a single part. Notwithstanding this single-part construction, the invention allows for the possibility that several cooling devices 1 can be combined with one another to form a cooling device group for each component 2 or assembly consisting of / containing at least one such component 2. In particular, the cooling devices 1 can also be assembled modularly to form a cooling device group.

[0026] The base element 4 and the cooling elements 6 are preferably made of or consist of a sintered material. Furthermore, the cooling elements 6 are preferably produced by forming from the base element 4, i.e., from the material of the base element 4, or from a preform for the production of the base element 4.

[0027] In the preferred embodiment, the base element 4 and the cooling elements 6 have a density of at least 98%, in particular at least 98.5%, preferably at least 99%, of the full density of the material used.

[0028] Solid density refers to the density of a cooling device manufactured using melt metallurgy from the same material, i.e., a component made from a solid material. A solid material in this context is a metallic material that—with the exception of defects—does not exhibit pores, such as those typically found in sintered components.

[0029] The base element 4 and the cooling elements 6 can also be manufactured using a different method or methods, for example by means of a so-called additive manufacturing process.

[0030] The cooling elements 6 are designed to be surrounded by a cooling fluid, for example water, so that the heat absorbed by the cooling device 1 is dissipated via this cooling fluid. Preferably, the cooling device 1 is a so-called pin-fin cooling device.

[0031] The cooling elements 6 of the illustrated embodiment are cylindrical. However, they can also have a different shape, for example a frustoconical, mushroom-shaped, or generally a cross-section that widens or narrows towards a cooling element head 7, for example a frustopyran shape.

[0032] The cross-section of the cooling elements 6 can be circular, oval, diamond-shaped, square, etc.

[0033] Furthermore, all cooling elements 6 can be identical. However, it is also possible to arrange or combine 4 cooling elements 6 with different shapes on a base element.

[0034] The cooling elements 6 have a cooling element height 8, measured from the first surface 5 of the base element 4. The cooling element height 8 can be, for example, between 2 mm and 30 mm, in particular between 3 mm and 15 mm.

[0035] The base element 4 has a base element height 9. The base element height 9 can, for example, be between 1 mm and 5 mm. The base element height 9 of the (plate-shaped) base element 4 is measured between the back side 3 and the first surface 5.

[0036] It may be stipulated that per dm 2 The first surface 5 is located between 300 and 1300, in particular between 300 and 1000, for example between 300 and 750, and cooling elements 6 are arranged or formed.

[0037] As from Fig. As can be seen in Figure 1, according to one embodiment of the cooling device 1, it can be provided that the rear side 3 of the base element 4 is formed with a flat surface.

[0038] It is intended that the base element 4 has a varying base element height 9 and that the cooling elements 6 have varying cooling element heights 8.

[0039] In this description, "Varying base element height 9" means that the base element height 9 is lower in at least one area or section of the base element 4 than in the remaining areas or sections of the base element 4. There may also be several areas or sections in the base element 4 that meet this condition.

[0040] In this description, "Varying cooling element heights 8" means that at least some of the cooling elements 6 have a cooling element height 8 that differs from the cooling element height 8 of the remaining cooling elements 6. The cooling elements 8 of a cooling device 1 can also have several different cooling element heights 8. Furthermore, it is possible that the cooling element height 8 already varies within the respective cooling element 6 itself.

[0041] It is further stipulated that the sum of the base element height 9 and the cooling element height 8 is the same in all areas of the base element 4 where cooling elements 6 are arranged. To illustrate this condition, refer to the Fig. 1 referred.

[0042] As from Fig. As can be seen in Figure 1, the base element 4 of this embodiment has a trough-shaped recess 10 on its first surface 5, i.e., on the front side where the cooling elements 6 are arranged. In this recess, the base element height 9 is reduced compared to the edge regions or sections of the base element 4. The cooling elements 6 arranged in this recess 10 are taller than those arranged in the edge regions or sections of the base element 4, and thus have a greater cooling element height 8. However, because the sum of the base element height 9 and the cooling element height 8 is the same for all areas where cooling elements are arranged, as described in the preceding figures, all cooling element heads 7 are at the same height, as shown in Figure 1. Fig. 1 is shown.

[0043] The trough-shaped recess 10 is preferably arranged or formed on the front side of the base element 4 in that section of the cooling device 1 which is intended for contact with the component 2, i.e., the section whose rear side 3 is intended for contact with the component 2. If the cooling device 1 is intended for contact with several components 2 via its rear side 3, several such recesses 10 may be provided on the front side, or a recess 10 may extend over several components 2 that abut the rear side 3.

[0044] The trough-shaped depression 10 can have a width in the direction of a device width 11 (see Fig. 2) have a width 11 that is smaller than or equal to the width 11 of the cooling device 1. Several recesses 10 may also be arranged side by side in the direction of the width 11.

[0045] Generally, if there are multiple recesses 10 in the base element 4, the base element height 9 between the recesses 10 can increase again to the maximum value of the base element height 9 of the base element 4, or to a value that lies in the range between this maximum height and the minimum height in at least one of the recesses 10. The maximum height is normally formed in the edge sections of the base element 4.

[0046] It is also possible that the recess 10 has a length corresponding to the device length 12 of the cooling device 1 (see Fig. 2) is equal to or smaller than. The preceding statements regarding the width of the recess 10 can be adapted accordingly to apply to the length of the recess.

[0047] Furthermore, it is possible that the recess 10 has a length equal to the device length 12 and a width equal to the device width 11, as long as the minimum base element height 9 is only formed in a partial area of ​​the base element 4. Fig. 1 This variant is indicated by dashed lines, in which the recess 10 extends to the edges of the side walls of the base element 4.

[0048] The shape of the recess 10 can be adapted to the shape of the component 2 (as viewed from above). However, the recess 10 can also have a larger surface area, as already described above. Alternatively, the recess can also have a smaller surface area on the front of the base element 4, so that, as viewed from above, the component 2 projects laterally beyond the recess 10, at least partially.

[0049] For example, the recess 10 can have a circular, oval, square, or generally polygonal shape in the top view.

[0050] According to one embodiment of the cooling device 1, the side walls 13 of the trough-shaped recess 10 are designed to run obliquely to the horizontal, as can be seen from Fig. As can be seen in Figure 1. An angle 14 of the side walls 13 to the horizontal can be selected between 5° and 50°.

[0051] After another and also in Fig. In the illustrated embodiment variant 1, cooling elements 6 can also be arranged on these inclined side walls 13, whereby the aforementioned embodiment variant with varying cooling element height 8 in the cooling element 6 itself can be obtained.

[0052] It is also possible that the recess 10 is formed with vertically running side walls 13, so that the aforementioned angle 14 to the horizontal is 90°.

[0053] The side walls 13 can be flat or curved or rounded.

[0054] The base element height 9 of the base element 4 can be reduced by at least 15%, and in particular by at least 25%, in areas with a reduced base element height 9, relative to the maximum base element height 9 of the base element 4. However, a minimum base element height 9 of 1 mm should not be undercut.

[0055] As from Fig. As can be seen from section 2, the cooling device 1 can have at least one stiffening element 15 on the first surface 5 of the base element 4. In the illustrated embodiment, the stiffening element 15 is rib-shaped, but it can also have a different shape. Since this stiffening element 15 or these stiffening elements can participate in the heat exchange, the preceding statements regarding their height apply to the cooling element height 8, so that stiffening element end surfaces 16 are arranged at the same height as cooling element end surfaces 17.

[0056] It is further possible that at least one stiffening element 15 or a stiffening element 15 is arranged on the rear side 3 of the base element 4 (in Fig. (2, indicated by dashed lines), particularly if the cooling device 1 has a larger surface area than the component 2, so that in this case too the component 2 can come into contact with the cooling device 1 over a large (flat) area. For example, in this embodiment, the component 2 can be arranged between stiffening elements 15.

[0057] Furthermore, it is possible that at least one stiffening element 15 is flush with the back side 3 or the first surface 5 and is made of a different, stiffer material than the rest of the base element 4.

[0058] When several stiffening elements 15 are arranged, they can all be provided with the same or different shape and / or length and / or size or design (on the first surface 5).

[0059] The stiffening element 15 can, for example, have a triangular, rectangular or trapezoidal cross-sectional shape, although other cross-sectional shapes are also possible.

[0060] In one embodiment, a stiffening element 15 can be provided between the end faces and the cooling elements 6 along the broad sides of the base element 4. Alternatively, the stiffening element 15 can be arranged continuously around the circumference of the base element 4.

[0061] The stiffening element 15 can be arranged between the edge of the base element and the cooling elements 6 and / or between the cooling elements 6.

[0062] The stiffening element 15 can have a straight path or, according to one embodiment, a non-straight path, in particular a wave-like path. According to another embodiment, it can also be provided that the stiffening element(s) 15 is / are arranged with a longitudinal extent at least approximately in one direction of flow of a cooling fluid through the cooling device 1.

[0063] In principle, the stiffening element 15 can be subsequently attached to the base element 4, for example, after the cooling elements 6 have been formed. However, according to one embodiment, the stiffening element 15 can be pressed along with the preform for the cooling device 1 from a sintered material or produced using powder metallurgy. According to another embodiment, the stiffening element 15 can be produced from the sintered material by forming it from the material of the base element 4, preferably simultaneously with the production of the cooling elements 6 from the preform. The stiffening element 11 or stiffening elements 11 are therefore preferably formed integrally with the base element 4 and the cooling elements 6.

[0064] What's next? Fig. As can be seen in Figure 2, the base element 4 can have a circumferential, rib-shaped edge. As indicated by the dashed lines, the area of ​​the cooling elements 6 can also be recessed relative to this edge, i.e., the recess 10 can be completely enclosed by side walls 13. In the Fig. In the illustrated embodiment of the cooling device 1, this edge is not present, so that the recess 10 is only provided with side walls 13 on two opposing sections. In other words, the recess 10 can extend over the entire width 11 of the device or only a section thereof.

[0065] In the preferred embodiment, a sintered powder or a powder used in powder metallurgy, particularly a metallic powder, is used to manufacture the cooling device 1. Preferably, a sintered powder with correspondingly good thermal conductivity is used. In particular, a sintered powder based on aluminum or an aluminum alloy, or based on copper or a copper alloy, or an MMC (metal matrix composite) powder is used.

[0066] The cooling device 1 is preferably manufactured using a powder metallurgy process; thus, the cooling device 1 is preferably a sintered component. For this purpose, a green compact is produced in a suitable mold (die) from a sintering powder, which can be produced from individual (metallic) powders by mixing, the powders optionally being pre-alloyed. Preferably, the green compact has a density of at least 80%, and in particular between 80% and 96%, of the material's full density.

[0067] The green compact can then be dewaxed at normal temperatures and sintered in one, two, or multiple stages, and subsequently preferably cooled to room temperature. Sintering can, for example, take place at a temperature between 500°C and 1300°C.

[0068] Since these procedures and the process parameters used are known from the prior art, reference is made to the relevant prior art in order to avoid repetition.

[0069] Sintering transforms the green compact into a preform 18, as exemplified in Fig. Figure 3 is shown. The preform 18 can be designed as a flat plate, so that the back side 3 and the first surface 5 can run parallel to each other.

[0070] According to one embodiment, the first surface 5 of the preform 18, on which the cooling structure and optionally at least one stiffening element 15 are formed, can be manufactured with a convex shape, at least in sections. Other shapes for the first surface 5 of the preform 18 are possible with regard to improved formability of the preform 18. For example, initial pin fin protrusions or cooling element protrusions (circular, oval, elliptical, etc.) with a height between 0.1 mm and 2.0 mm can be preformed. Likewise, protrusions of at least one stiffening element 15 can optionally be provided.

[0071] The preform 18 can subsequently be compacted. This compaction can take place simultaneously with the forming of the preform 18 into the cooling elements 6 and, if applicable, the stiffening element(s) 15.

[0072] The preform 18 is formed in a forming tool 19. For this purpose, the preform 18 is placed in or against the forming tool 19. In the simplest case, the forming tool 19 for the production of the cooling elements 6 is formed by a perforated plate 20. The perforated plate 20 has recesses 21, in particular openings, into or through which a portion of the material of the preform 18 is pressed, thereby forming the cooling elements 6. Depending on their shape, corresponding elongated or wave-shaped recesses or openings can be provided in the perforated plate 20 for the formation of the stiffening element(s) 15.

[0073] The remainder of the material of the preform 18, which is not pressed into or through the forming tool 19, forms the base element 4.

[0074] The recesses 21, i.e. their cross-section, are adapted to the cross-section of the cooling elements 6 to be manufactured.

[0075] The forming tool 19 can also look different; it does not necessarily have to be a perforated plate 19. In particular, the forming tool 19 can be designed in a "cup-shaped" form as a die.

[0076] For the forming process, a punch 22 is applied to the rear side 3 of the preform 18, which also forms the rear side 3 of the base element 4, and pressed onto the preform 18 with a predetermined pressure. The forming process can, for example, be carried out at a pressure between 700 MPa and 1600 MPa. Furthermore, the forming process can be carried out for a period of up to 10 seconds, in particular between 0.1 seconds and 10 seconds. The forming process is preferably carried out at room temperature (20 °C), i.e., cold, or the forming process can also be carried out after preheating the preform 18 to a temperature between 50 °C and 300 °C, for example between 50 °C and 150 °C, and / or in / with a forming tool 18 heated to a temperature between 50 °C and 300 °C, for example between 50 °C and 150 °C.

[0077] After forming, i.e., after the preform 18 has been shaped, the cooling device 1 can be finished. However, post-processing of the cooling device 1 is also possible. For example, the cooling elements 6 and / or the stiffening element(s) 15 can be re-compacted, at least in certain areas, for example at the free ends.

[0078] The forming of the preform 18 can be carried out in one or more stages, so that the cooling elements 6 and / or the stiffening element(s) 15 can be formed in one or more steps.

[0079] To form at least one recess 10 in the base element, the forming tool 19 can be designed with a corresponding projection 23 on the surface that comes into contact with the first surface 5 of the base element 4. This eliminates the need for subsequent machining to form the recess 10.

[0080] Furthermore, it is possible that the cooling elements 6 and / or the stiffening element(s) 15 are provided with a coating, in particular a corrosion-resistant one.

[0081] As explained above, the cooling device 1 can also be manufactured using a different method, for example an additive manufacturing process.

[0082] The examples shown illustrate possible design variants, although it should be noted that combinations of the individual design variants are also possible.

[0083] Finally, for the sake of clarity, it should be noted that, for a better understanding of the construction of the cooling device 1 or the forming tool 19, these are not necessarily shown to scale. Reference symbol list 1 cooling device 2 components 3 Back 4 Basic element 5 Surface 6 cooling elements 7 Cooling element head 8 Cooling element height 9 Base element height 10 In-depth study 11 Device width 12 Device length 13 Side wall 14 angles 15 stiffening element 16 stiffening element end surface 17 Cooling element end surface 18 preforms 19 Forming tool 20 perforated plate 21 Exclusion 22 stamps 23 lead QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2019 108 106 A1

[0003] DE 10 2018 216 859 A1

[0004] AT 526 330 A4

[0005]

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