Control unit with improved cooling

Abstract

The present invention relates to a control device, comprising: a carrier plate (9) on which electronic flat components (2b) and electronic 3D components (2a) which have larger dimensions than the flat components (2b) are arranged, a first, fluid-tight housing (3) in which the carrier plate (9) is arranged, an electrically non-conductive first cooling liquid (7) which is arranged in the first housing (3) and configured to dissipate heat from the 3D components (2a), and a cooling unit (5) arranged on a wall side of the first housing (3) through which a second cooling liquid (8) which is completely separate from the first cooling liquid (7) can flow, such that heat absorbed by the first cooling liquid (7) can be dissipated as a first heat flow (Q1) via a wall region (33) of the first housing (3) to the environment and as a second heat flow (Q2) via the cooling unit (5) to the second cooling liquid (8).

Description

State of the art

[0001] The present invention relates to a control unit, in particular an automotive control unit, with an improved possibility for dissipating heat from electronic and electrical components of the control unit, in particular by means of two separate cooling circuits.

[0002] In control units, particularly in the automotive sector, not only power amplifiers (flat components) but also voluminous 3D components, which are larger than flat components, particularly in terms of their volume, must be cooled. Examples of such 3D components include coils, transformers, or capacitors. In contrast to flat components, which are essentially two-dimensional and, in particular, offer a clearly defined heat dissipation area, cooling 3D components is complex. Furthermore, 3D components are often enclosed in potting material, which further complicates the cooling of such 3D components. Furthermore, the potting compound complicates repairs or recycling processes after the end of the control unit's service life. Disclosure of the invention

[0003] The control unit according to the invention with the features of claim 1 has the advantage that significantly improved cooling of 3D components, in particular coils, transformers, capacitors, or the like, is possible. In particular, the present invention can avoid the use of potting materials which, in the prior art, enclose and surround such 3D components. This eliminates problems with temperature changes, since the potting materials usually have a different thermal expansion coefficient than the encapsulated 3D components. Furthermore, by omitting the potting compound, weight can be reduced and costs, both material costs due to the omission of potting compound and manufacturing costs, can be reduced. Furthermore, the control unit according to the invention can also be repaired relatively easily, since a defective 3D component can be replaced without any problems.There are also advantages when it comes to recycling requirements.

[0004] This is achieved according to the invention in that the control unit has a carrier plate, in particular a printed circuit board or a busbar, with electronic flat components and 3D components. The 3D components have larger dimensions than the flat components, in particular with regard to their total volume and their height starting from the carrier plate. The flat components are preferably essentially two-dimensional components, which in particular have a clear, large-area heat dissipation surface. Furthermore, the control unit comprises a fluid-tight, sealed first housing in which the carrier plate is arranged. An electrically non-conductive first cooling liquid, in particular an oil, is arranged in the sealed housing. The first cooling liquid is designed to dissipate heat from the 3D components.The control unit further comprises a cooling unit arranged in one side of the first housing, through which a second cooling fluid, which is separate from the first cooling fluid, can flow. Heat generated by the 3D component and absorbed by the first cooling fluid can be dissipated as a first heat flow Q1 through a wall of the first housing to the environment and as a second heat flow Q2 through the cooling unit. Thus, the control unit can be cooled by two separate cooling fluids, with the cooling process being realized by means of two different heat flows Q1, Q2.

[0005] The wall of the first housing, via which heat is dissipated by means of the first heat flow Q1, is preferably made of a material with good heat conduction, in particular a metal.

[0006] The subclaims show preferred developments of the invention.

[0007] Preferably, a heat exchanger is provided between the first and second cooling liquids. The heat exchanger is preferably integrated into a wall of the first housing, in particular a bottom of the first housing. The heat exchanger further preferably has first and second fins, with the first fins projecting into the space in which the first cooling liquid is present, and the second fins projecting into the space in which the second cooling liquid is present.

[0008] Further preferably, the cooling unit through which the second cooling fluid flows is integrated into a wall of the first housing, in particular the bottom of the first housing. This allows for a simple and particularly compact design. Furthermore, by utilizing the wall of the first housing, a large heat transfer surface, which is preferably completely filled by the heat exchanger between the first and second cooling fluids, can be covered.

[0009] According to a further preferred embodiment of the invention, a filler material is arranged between the 3D component and the heat exchanger. The filler material is preferably made of a material that conducts heat very well, in particular a thermal paste or a highly thermally conductive adhesive. The filler material is thus arranged only locally and preferably in a limited manner on the 3D component, on the side facing the heat exchanger. The filler material additionally fixes the 3D component and nevertheless allows the first cooling fluid to flow around large areas of the 3D component in order to dissipate heat from the 3D component.

[0010] The carrier plate preferably has at least one through-opening configured to allow the first cooling fluid to flow through. A plurality of through-openings are preferably formed in the carrier plate, in particular to allow a circumferentially closed flow of the first cooling fluid in the first housing.

[0011] The control unit further preferably comprises a conveying device, in particular a pump or a rotating vane element, which is provided for moving the first cooling liquid in the first housing. The control unit preferably has a temperature sensor in the first housing to detect the temperature of the first cooling liquid, with the conveying device being controlled based on the detected temperature value by the temperature sensor. The conveying device can thus only be activated when increased cooling capacity is necessary to dissipate heat from the 3D component.

[0012] Preferably, the carrier plate is arranged in the first housing at a distance from a bottom and a cover area of ​​the first housing in order to enable good airflow.

[0013] The control unit further preferably comprises a second housing in which the first cooling fluid and 3D components are arranged. This allows the 3D components to be separated from other components of the control unit and to be cooled in a targeted manner. Preferably, the second housing is arranged entirely within the first housing. This allows the first and second housings to be nested such that the first housing completely accommodates the second housing.

[0014] Preferably, the second housing has a separate second cover, with the remaining wall areas of the second housing being parts of the first housing. This allows for a particularly compact and cost-effective design.

[0015] Preferably, all flat components of the control unit are arranged outside the second housing and / or all 3D components are arranged inside the second housing.

[0016] According to a further preferred embodiment of the invention, the first housing has a closable filling opening configured for filling the first cooling liquid. If the control unit also has the second housing, the filling opening is preferably arranged on the first housing such that the first cooling liquid can be filled directly into the hollow area of ​​the second housing. In this case, a part of the second housing need only be provided as a wall area of ​​the first housing, i.e., a wall area of ​​the first housing is simultaneously also a wall area of ​​the second housing.

[0017] The first housing and / or the second housing are particularly preferably made of a metal material.

[0018] The control unit is preferably a control unit for automotive applications, which preferably has power electronic control units, e.g. a charger for battery charging with an integrated current converter (charger converter) or an inverter. Short description of the drawings

[0019] Embodiments of the invention are described in detail below with reference to the accompanying drawings. In the drawing: Fig. 1 a schematic sectional view of a control device according to a first embodiment of the invention, Fig. 2 a schematic sectional view of a control device according to a second embodiment of the invention, and Fig. 3 a schematic partial sectional view of a control device according to a third embodiment of the invention. Preferred embodiments of the invention

[0020] The following is based on reference to Fig. 1 a control unit 1 according to a first preferred embodiment of the invention is described in detail.

[0021] Fig. Figure 1 schematically shows a sectional view of a control unit for automotive applications. The control unit comprises two types of electronic components, namely 3D components 2a and flat components 2b. The 3D components 2a have larger dimensions than the flat components 2b. The flat components 2b are preferably mounted directly on a carrier plate 9 and have a flat side for heat dissipation.

[0022] Compared to the flat components 2b, the 3D components 2a are voluminous, large and taller components, e.g. coils or transformers or capacitors or the like.

[0023] The control unit 1 further comprises a first housing 3, in which the carrier plate 9 is completely arranged. The housing 3 comprises a housing base body 30 and a cover 31. The housing 3 is preferably made of a metallic material. The housing 3 is sealed in a fluid-tight manner and has a first cooling liquid 7 in an interior space. The first cooling liquid 7 preferably completely fills the interior of the housing 3.

[0024] The first cooling liquid 7 can be filled and, if necessary, emptied via a filling opening 13, which can be closed by means of a screw plug 40.

[0025] The control unit 1 further comprises a cooling unit 5. A second cooling liquid 8 flows through the cooling unit 5.

[0026] The cooling unit 5 is integrated into the housing 3. As can be seen from Fig. As can be seen in Figure 1, the housing 3 has a base 32 and side walls 33. The cooling unit 5 is integrated into the base 32. Preferably, the cooling unit 5 covers the entire bottom surface of the base 32.

[0027] How to continue Fig. 1, a heat exchanger 6 is arranged between the cooling unit 5 and the interior of the housing 3 filled with the first cooling liquid 7.

[0028] The heat exchanger 6 has first fins 61 and second fins 62. The first fins 61 protrude into the interior of the housing 3 and are in contact with the first cooling liquid 7. The second fins 62 protrude into a cooling channel 11 of the cooling unit 5 and are in contact with the second cooling liquid 8. As can be seen from Fig. 1, the first cooling liquid 7 and the second cooling liquid 8 are completely separated from each other.

[0029] The housing 3 has a kind of double bottom in which the cooling unit 5 and the heat exchanger 6 are integrated.

[0030] How to continue Fig. As can be seen in Figure 1, the carrier plate 9 has through-openings 90. The through-openings 90 allow circulation of the first cooling fluid 7 for better heat absorption.

[0031] The control unit 1 has several carrier plates 9, which are supplied with electrical power through the housing via a plug 14. This is shown in Fig. 1 shown only schematically.

[0032] Furthermore, in particular for improved heat transfer, the 3D components 2a can be directly connected to the heat exchanger 6 by means of filling material 12. As can be seen from Fig. As can be seen in Figure 1, a filler material 12 is arranged on a 3D component 2a to enable direct heat conduction to the first fins 61 of the heat exchanger 6. This can ensure improved heat transfer to the heat exchanger 6.

[0033] The filler material 12 is preferably a thermal paste or a highly thermally conductive adhesive. The filler material 12 can also be used to improve the fixation of relatively heavy and large 3D components 2a.

[0034] The 3D components 2a are, as in Fig. 1, free of any potting material or the like. This allows heat to be transferred directly from the 3D component 2a to the first cooling liquid 7.

[0035] How to continue Fig. As can be seen in Figure 1, the heat originating from the 3D components 2a can then be transferred from the first cooling fluid 7 to an outside by means of first heat flows Q1 and simultaneously transferred via the heat exchanger 6 as a second heat flow Q2 to the second cooling fluid 8. This ensures rapid and reliable cooling of the 3D components 2a, which can generate large amounts of heat during operation due to their size.

[0036] As from Fig. As can be seen in Figure 1, the housing 3 has an inner wall region 34 located inside the housing, which in particular separates 3D components 2a from the flat components 2b. An opening 35 is provided in the inner wall region 34 for improved circulation.

[0037] Thus, the control unit 1 has two main paths for dissipating heat, namely via the first heat flow Q1 to the housing walls to the environment and the second heat flow Q2 via the heat exchanger to the cooling unit 5.

[0038] The first cooling liquid 7 is an electrically non-conductive liquid which transfers heat from the 3D components 2a to the housing walls and the cooling unit 5 with the second cooling liquid 8.

[0039] The heat dissipation can be supported by additional measures, such as natural convection, which is preferably generated by density differences of the first cooling liquid 7.

[0040] This allows for a significantly higher power density of the electronic components due to higher insulation strength while maintaining the same size of the housing 3. In particular, the 3D components 2a can be arranged without encapsulation compound. This eliminates the need for encapsulation material, enabling improved heat transfer from the 3D components to the first cooling liquid 7. Furthermore, the elimination of encapsulation compound ensures repairability. For this purpose, the first cooling liquid 7 can be emptied via the filling opening 13, and then the cover can be removed from the remaining housing. Furthermore, the electronic power components, in particular the 3D components 2a, can be designed smaller, as better heat dissipation is ensured.

[0041] Filling of the housing 3 with the first cooling liquid 7 can be made possible via the filling opening 13 after complete assembly of the components of the control unit 1.

[0042] It should also be noted that the additional second cooling liquid 8 and thus the second cooling unit 5 may possibly be dispensed with if the cooling of the 3D components 2a is only possible via the first cooling liquid 7.

[0043] Fig. Figure 2 shows a control unit 1 according to a second embodiment of the invention, wherein identical or functionally identical parts are designated by the same reference numerals. In contrast to the first embodiment, the second embodiment includes a first housing 3 and a second housing 4. The second housing 4 has a housing base body 40 and a second cover 41. As shown in Fig. As can be seen in Figure 2, the housing base body 40 is formed exclusively by parts of the housing base body 30 of the first housing 3. In particular, outer walls of the first housing 3 and an inner wall region 34 form a housing base body for the second housing 4.

[0044] As in Fig. 2, all 3D components 2a are arranged within the second housing 4. The flat components 2b are all arranged outside the second housing 4 but within the first housing 3. In this case, the flat components 2b are not in contact with the first cooling liquid 7, which is only present in the second housing 4. The second housing 4 is thus completely contained in the first housing 3. This results in a nesting of the first housing 3 and the second housing 4. Since only the 3D components 2a come into contact with the first cooling liquid 7, the flat components 2b can be selected arbitrarily and in particular independently of the type of first cooling liquid 7, without this resulting in any restrictions with regard to compatibility with the first cooling liquid 7.Thus, on the one hand, a first heat flow Q1 can be realized via the two covers 41, 31 and via the side wall 33 to the environment, and a second heat flow Q2 can be transferred via the heat exchanger 6 to the second cooling fluid 8. This ensures very good heat dissipation of the 3D components 2a. Otherwise, this embodiment corresponds to the first embodiment, so reference can be made to the description given there.

[0045] Fig. Figure 3 shows an enlarged partial sectional view of a third embodiment of the invention. In contrast to the previous embodiments, in the third embodiment, forced circulation can be enabled by means of a conveying device 17. In this embodiment, the conveying device 17 is fixed to the carrier plate 9 and enables forced conveyance of the first cooling liquid 7. This is shown schematically in Fig. 3 by the arrows A. Thus, a forced circulation flow can be realized. The conveyor device 17 is preferably arranged in an opening 91 in the carrier plate 9. It should be noted that such a conveyor device is used both in the first embodiment of Figure 1 and in the second embodiment of Figure 1. Fig. 2 can be provided. Furthermore, a temperature sensor 21 is arranged in the area of ​​the first cooling liquid 7. The temperature sensor 21 is connected to a control unit for the conveying device 17 and can continuously measure the temperature of the first cooling liquid 7.

[0046] Once predetermined threshold values ​​are reached, the control unit of the conveyor device 17 can operate or deactivate the conveyor device 17, enabling efficient and, in particular, energy-saving cooling of the 3D components 2a. Otherwise, this embodiment corresponds to the previous embodiments, so reference can be made to the description given there.

Claims

[1] Control unit comprising: - a carrier plate (9) on which electronic flat components (2b) and electronic 3D components (2a) which have larger dimensions than the flat components (2b) are arranged, - a first, fluid-tight housing (3) in which the carrier plate (9) is arranged, - an electrically non-conductive first cooling liquid (7) which is arranged in the first housing (3) and is designed to dissipate heat from the 3D components (2a), and - a cooling unit (5) arranged on a wall side of the first housing (3), through which a second cooling liquid (8) which is completely separate from the first cooling liquid (7) can flow, so that heat absorbed by the first cooling liquid (7) can be dissipated as a first heat flow (Q1) via a wall region (33) of the first housing (3) to the environment and as a second heat flow (Q2) via the cooling unit (5) to the second cooling liquid (8). [2] Control device according to claim 1, wherein the cooling unit (5) has a heat exchanger (6) which is arranged between the first cooling liquid (7) and the second cooling liquid (8). [3] Control device according to claim 2, wherein the heat exchanger (6) has first fins (61) and second fins (62), wherein the first fins (61) are immersed in the first cooling liquid (7) and the second fins (62) are immersed in the second cooling liquid (8). [4] Control device according to one of the preceding claims, wherein the first housing (3) has an integrated cooling channel (11) for the second cooling liquid (8) on a wall region, in particular a bottom. [5] Control device according to one of claims 2 to 4, wherein a filling material (12), in particular thermal paste or adhesive, is arranged between the 3D component (2a) and the heat exchanger (6) in order to transfer heat from the 3D component (2a) to the heat exchanger and to fix the 3D component (2a). [6] Control device according to one of the preceding claims, wherein the carrier plate (9) has through-openings (90) which are arranged for the flow through of the first cooling liquid (7). [7] Control device according to one of the preceding claims, further comprising a conveying device (17) arranged to move the first cooling liquid (7) in the first housing (3). [8] Control device according to one of the preceding claims, wherein the carrier plate (9) is arranged at a distance from a base (32) and a cover (31) of the first housing (3). [9] Control device according to one of the preceding claims, further comprising a second housing (4) in which the 3D components (2a) are arranged. [10] Control device according to claim 9, wherein the second housing (4) is arranged entirely within the first housing (3). [11] Control device according to one of claims 9 or 10, wherein the second housing (4) is formed by a separate second cover (41) and wall regions of the first housing (3). [12] Control device according to one of claims 9 to 11, wherein all flat components (2b) are arranged outside the second housing (4) and / or wherein all 3D components (2a) are arranged inside the second housing (4). [13] Control device according to one of claims 9 to 12, wherein an inner wall region (34) of the first housing (3) forms a housing wall of the second housing (4).

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