Cooling arrangement for cooling electronic components of a motor vehicle and method for its manufacture

Abstract

Cooling arrangement (10) for cooling electronic components (12) of a motor vehicle, comprising - a plate-like cooling channel cover (14), on the first side (141) of which an electronic component (12) to be cooled is fixed in thermal contact at a cooling position (143), and on the second side (142) opposite the first side (141) in the area of ​​the cooling position (143) a turbulence mat (18) is fixed in a materially bonded manner, - and a coolant guide housing (20) in which an inlet channel (201) and outlet channel (202) through which a coolant flows are arranged, and whose cover plate (16) which is fluid-tightly connected to the second side (142) of the cooling channel cover (14) has a turbulence mat receiving recess (24) forming a cooling channel (22), which is fluidly connected to the inlet channel (201) via a coolant inlet opening (241) and to the outlet channel (202) via a coolant outlet opening (242), and into which the turbulence mat (18) is inserted, characterized in that the turbulence mat (18) is laser-welded to the cooling channel cover (14) on one side, while it projects into the bottom of the turbulence mat receiving recess (24) without forming a material-bonded connection with it, wherein the cooling channel cover (14) is connected to the circumference of its second side (142) with the The cover plate (16) of the coolant guide housing (20) is laser welded.

Description

[0001] The invention relates to a cooling arrangement for cooling electronic components of a motor vehicle, comprising - a plate-like cooling channel cover, on the first side of which an electronic component to be cooled is fixed in thermal contact at a cooling position, and on the second side opposite the first side in the area of ​​the cooling position a turbulence mat is fixed in a material-bonded manner, - and a coolant guide housing in which an inlet channel and outlet channel through which a coolant can flow are arranged, and whose cover plate, which is fluid-tightly connected to the second side of the coolant channel cover, has a turbulence mat receiving recess forming a coolant channel, which is flow-connected to the inlet channel via a coolant inlet opening and to the outlet channel via a coolant outlet opening, and into which the turbulence mat is inserted.

[0002] The invention further relates to a method for manufacturing a cooling arrangement for cooling electronic components of a motor vehicle, comprising the following steps: - Providing a plate-like cooling channel cover, on the first side of which an electronic component to be cooled is fixed in thermal contact at a cooling position, - Providing a turbulence mat, - Providing a coolant guide housing open on the lid side, in which an inlet channel and outlet channel through which a coolant can flow are arranged, - Providing a cover plate for the coolant guide housing, which has a turbulence mat receiving recess forming a cooling channel with a coolant inlet opening for flow connection with the inlet channel and a coolant outlet opening for flow connection with the outlet channel, - Fabric-bonded fixing of the turbulence mat to the second side of the cooling channel cover opposite the first side in the area of ​​the cooling position.

[0003] A generic cooling arrangement and a generic manufacturing process are described in the German patent application DE 10 2020 207 966.8, which was unpublished on the filing date of the present application.

[0004] From DE 10 2012 107 684 A1, a heat sink for at least one electronic component to be cooled is known. The heat sink comprises a base plate and a top plate, between which turbulators are arranged to improve heat transfer. The special structuring of the turbulators enables particularly efficient heat dissipation.

[0005] DE 10 2019 202 903 A1 discloses a system for monitoring a high-voltage electrical system of a vehicle. In particular, an arrangement and a method for detecting fault conditions in a high-voltage system are described, wherein sensors and an evaluation unit are used to detect safety-relevant deviations and to initiate suitable protective measures.

[0006] German patent application DE 10 2015 226 023 A1 discloses a system for monitoring the high-voltage electrical system of a motor vehicle. In particular, it describes an arrangement in which sensors and an evaluation unit are used to detect fault conditions in the high-voltage system and to initiate appropriate protective measures. This enables reliable detection of insulation faults and other safety-relevant deviations.

[0007] WO 2014 / 095 171 A1 discloses a system for monitoring a vehicle's high-voltage electrical system. In particular, it describes an arrangement in which sensors and an evaluation unit are used to detect fault conditions in the high-voltage system and initiate appropriate protective measures. This enables reliable detection of safety-relevant deviations in the high-voltage network.

[0008] High power levels are handled in the power electronics of motor vehicles, particularly in all-electric or electro-hybrid vehicles. The electronic components used for this purpose, such as power modules (e.g., IGBTs), require cooling systems to dissipate the heat generated. These electronic components are often equipped with cooling structures, such as labyrinthine cooling fins, around which a coolant, typically liquid, flows. These cooling structures can be attached directly to the electronic component and extend into a coolant channel (or cooling channel). However, it is also known to connect the electronic components to a plate covering an opening of the cooling channel and to attach the cooling structures to the opposite side of this plate-shaped cooling channel cover, facing the cooling channel.

[0009] The aforementioned patent application discloses a cooling arrangement for cooling electronic components of a motor vehicle, comprising a plate-like cooling channel cover. In this arrangement, electronic components to be cooled are fixed in thermal contact, in particular soldered or sintered, at several locations, each referred to as a cooling position, on a first side of the cooling channel cover. On the second side of the cooling channel cover, opposite the first side, a turbulence mat is soldered in the area of ​​each cooling position. A turbulence mat is defined here as any flat structure through which coolant can flow parallel to the plane of expansion and which thereby induces turbulence in the coolant flow.In the generic application, the embodiment of such a turbulence mat, which is also preferred in the context of the present application, is described as an arrangement of corrugated sheet strips connected with phase offset with respect to the wave period.

[0010] The second side of the cooling channel cover is soldered fluid-tight to the cover plate of a coolant guide housing, inside which an inlet channel and an outlet channel, both through which coolant flows, are arranged. The cover plate of the coolant guide housing has recesses, referred to here as turbulence mat receiving recesses, at the positions where the turbulence mats are located. These recesses serve to form a cooling channel, limited to the cooling position, between the coolant guide housing and the cooling channel cover, and to receive the turbulence mat. The turbulence mats inserted into the receiving recesses are each soldered to the bottom of the recesses on their underside facing away from the cooling channel cover.

[0011] Coolant can enter the cooling channel from inside the coolant housing through a coolant inlet opening that is flow-connected to the inlet channel. Conversely, the coolant flows back from the cooling channel into the interior of the coolant housing through a coolant outlet opening that is flow-connected to the outlet channel.

[0012] To manufacture this known device, the electronic component is first soldered or sintered onto the cooling channel cover, before the latter is then soldered to the turbulence mat and the cover plate of the coolant guide housing – as described above. Only then are the remaining parts of the coolant guide housing fixed to its cover plate.

[0013] A disadvantage of this known device is that the solder joints between the turbulence mat and the cooling channel cover, the solder joints between the turbulence mat and the cover plate of the coolant guide housing, and the full-surface solder joint between the cooling channel cover and the cover plate of the coolant guide housing outside the cooling position—at least when soldering—require an additional layer of solder. This is not only cost- and manufacturing-wise inconvenient, but the additional layer also increases the thickness of the cooling channel cover in the area of ​​the cooling positions, thus hindering the cooling of the electronic components.Furthermore, a solder joint is generally not very robust against mechanical influences and higher temperatures, so comparatively large areas have to be joined together in a material-bonded manner to achieve sufficient mechanical stability of the cooling arrangement, which makes the production of the cooling arrangement particularly complex.

[0014] The object of the present invention is to provide a cost-effective, easy-to-manufacture cooling arrangement that enables particularly efficient cooling of the electronic components, as well as a method for its manufacture.

[0015] This problem is solved in conjunction with the features of the preamble of claim 1 by laser-welding the turbulence mat to the cooling channel cover on one side, while projecting into the bottom of the turbulence mat receiving recess without forming a material-bonded connection with it, wherein the cooling channel cover is laser-welded to the cover plate of the coolant guide housing on the circumference of its second side.

[0016] The problem is further solved in conjunction with the features of the preamble of claim 6 by fixing the turbulence mat to the cooling channel cover in a materially bonded manner by means of laser welding, and fixing the cover plate to the coolant guide housing in a manner that closes the cover side of the coolant guide housing, before the cooling channel cover is then placed onto the cover plate of the coolant guide housing in such a way that the turbulence mat fixed to the cooling channel cover projects into the bottom of the turbulence mat receiving recess without forming a materially bonded connection with it, whereupon the cooling channel cover is fluid-tightly connected to the cover plate of the coolant guide housing on the circumference of its second side by means of laser welding.

[0017] Preferred embodiments are the subject of the dependent claims.

[0018] In the cooling arrangement and manufacturing process according to the invention, both the turbulence mat and the cover plate of the coolant guide housing are laser-welded to the cooling channel cover. The use of laser welding technology enables the use of delicate cooling structures, such as the turbulence mat in the preferred embodiment, as well as the use of thin-walled sheets for the cooling channel cover and / or the cover plate of the coolant guide housing. The use of such thin-walled sheets as a layer between the heat-generating electronic component and the cooling channel carrying the coolant leads to more efficient cooling of the electronic component because more heat is transferred from the electronic component to the coolant via the thinner layers.

[0019] Furthermore, according to the invention, the turbulence mat, which is enclosed by a cooling channel wall formed by the cooling channel cover as well as the side walls and the bottom of the turbulence mat receiving recess, is connected to this wall only on one side. More precisely, the turbulence mat is laser-welded exclusively to the cooling channel cover, while there is no material bond between it and the bottom of the turbulence mat receiving recess. It has been found that attaching the turbulence mat to one side, on the side supporting the electronic power components, is sufficient to ensure adequate mechanical stability of the cooling arrangement.

[0020] The fact that, according to the invention, the turbulence mat is first fixed to the cooling channel cover carrying the electronic component, and the coolant guide housing is connected to its cover plate before the two parts are joined together, allows the cooling channel cover to be easily placed onto the cover plate and subsequently laser-welded around its circumference for the final connection of the components. The manufacturing process for the cooling arrangement according to the invention is therefore particularly simple. Furthermore, costs are saved because the laser welding technique, as described, is used multiple times, namely for attaching both the turbulence mat and the cover plate of the coolant guide housing to the cooling channel cover. This eliminates the need for a machine change.

[0021] Furthermore, it is advantageous that the thermally sensitive electronic component, which is already fixed to the cooling channel cover during the laser welding steps, is not damaged by the use of a highly localized thermal joining method such as laser welding.

[0022] Ideally, a turbulence mat is used that is dimensioned so that, after the cooling channel cover is placed on the cover plate, it rests against the bottom of the turbulence mat's receiving recess. In the completed cooling assembly, the turbulence mat thus ideally rests against the bottom of the receiving recess. This means there is no gap between the underside of the turbulence mat and the bottom of the receiving recess. This ensures that all coolant passing through the cooling channel flows through the structure of the turbulence mat. In this way, the time the coolant takes to travel from entering the cooling channel through the coolant inlet to exiting through the coolant outlet is maximized, resulting in greater heat absorption per unit volume of coolant.The heat absorption by the coolant is therefore more efficient than if the turbulence mat were spaced away from the bottom of the recess and some of the coolant flowed along the bottom of the recess without passing through the turbulence mat, being set into turbulence by it, and absorbing waste heat from the electronic component. However, a small gap between the turbulence mat and the bottom of the recess is harmless in most cases.

[0023] In a further development of the invention, the cooling channel cover is additionally bonded to the cover plate of the coolant guide housing at point connections located on the second side of the cooling channel cover, spaced apart from its outer edge and outside the cooling position. Thus, the cooling channel cover is bonded to the cover plate of the coolant guide housing not only around the circumference of its second side but also via these point connections. The point connections are located on the second side of the cooling channel cover, but not at its outer edge and not at the cooling position where the turbulence mat is fixed. This additional bond connection between the cooling channel cover and the cover plate of the coolant guide housing provides the entire cooling assembly with greater mechanical stability.In particular, larger quantities of coolant can be routed through the cooling channel in a shorter time without the resulting higher pressure in the cooling channel forcing the cooling channel cover and the cover plate of the coolant guide housing apart and allowing coolant to penetrate the resulting gap between the cooling channel cover and the cover plate. It has been found that to achieve the described advantages, it is sufficient if the additional bonded connection exists only at a few individual points. This embodiment is therefore particularly economical, as a full-surface bonded connection between the cooling channel cover and the cover plate of the coolant guide housing is not required.

[0024] Preferably, the cooling channel cover is welded to the cover plate of the coolant guide housing at the material-bonded joints, particularly by laser welding. A welded connection offers the advantage over other material-bonded connections such as adhesive bonds and soldered joints that it is particularly robust against mechanical stress and higher temperatures. The welded connections can therefore withstand even higher pressures in the cooling channel, as described above. Welded connections are also suitable for cooling arrangements with electronic components that generate a comparatively high amount of heat. This is because the welded connections can withstand even higher levels of heat loss that can be transferred to the material-bonded joints via conduction through the cooling channel cover.

[0025] Preferably, the material bond joints are designed as openings in the cooling channel cover, at the inner circumference of which the cooling channel cover is welded, in particular by laser welding, to the cover plate of the coolant guide housing. The openings are continuous openings in the cooling channel cover, so that after the cooling channel cover is placed on the cover plate, the surface of the cover plate is visible at the material bond joints and accessible to a laser welding beam. The openings thus enable straightforward, highly localized laser welding of the cooling channel cover to the cover plate at the material bond joints, with a weld seam forming exclusively on the inner circumference of the openings.Laser welding is particularly advantageous because, unlike other welding methods, very thin-walled sheets can be used for the cooling channel cover and / or the cover plate of the coolant guide housing. As described above, this improves the cooling of the electronic component. Furthermore, laser welding results in highly localized heat input, making this type of connection particularly gentle on the thermally sensitive electronic component attached to the cooling channel cover. Finally, the effort and costs of the manufacturing process are reduced because the laser welding technology is already available, having been used for the material-bonded attachment of the turbulence mat to the cooling channel cover and for attaching the cover plate of the coolant guide housing to the cooling channel cover around its circumference.

[0026] Further details and advantages of the invention will become apparent from the following specific description and the drawings.

[0027] They show: Fig. 1: A perspective view of a cooling duct cover with electronic components attached to it, Fig. 2: a perspective view of a turbulence mat, Fig. 3a: a perspective view of a coolant guide housing with a cover plate attached to it, Fig. 3b: a sectional view of the coolant guide housing made of Fig. 3a, Fig. 4: laser welding of the turbulence mat made of Fig. 2 on the second side of the cooling duct cover Fig. 1, Fig. 5: attaching the cooling duct cover Fig. 4 onto the cover plate of the coolant guide housing Fig. 3a, Fig. 6: laser welding of the cooling channel cover to the cover plate of the coolant guide housing made of Fig. 5 in their size and Fig. 7: laser welding of the cooling channel cover to the cover plate of the coolant guide housing made of Fig. 6 at the material-bonding connection points formed as perforations.

[0028] Identical reference symbols in the figures indicate identical or analogous elements. Fig. Figure 1 shows a perspective view of a plate-like cooling channel cover 14 suitable for manufacturing a cooling arrangement according to the invention. On the first side 141 of this cover, three electronic components 12 are already fixed in thermal contact at intervals from one another. The cooling channel cover 14 is a copper-coated aluminum sheet on which the electronic components 12 have been fixed by sintering, in particular silver sintering with a silver sintering paste at 250 °C and 20 MPa. The positions at which the electronic components 12 are fixed define the cooling positions 143 of the cooling arrangement. To manufacture a cooling arrangement according to the invention, such a cooling channel cover 14 is provided in a first step. The specific joining technique used for attaching the electronic component(s) 12 to the cooling channel cover 14 is not relevant within the scope of the present invention.In any case, it should establish good thermal contact between the electronic component(s) 12 and the cooling channel cover 14.

[0029] In Fig. Figure 2 shows a turbulence mat 18, which is also to be provided for the manufacture of a cooling arrangement according to the invention. The turbulence mat 18 is designed as an arrangement of corrugated metal strips which are connected to each other with a phase shift with respect to the wave period.

[0030] The Fig. Figures 3a and 3b show a coolant guide housing 20 suitable for manufacturing a cooling arrangement according to the invention, on which a cover plate 16 has already been fixed in a manner that closes the coolant guide housing 20. Three turbulence mat receiving recesses 24 are visible in the cover plate 16, which can receive turbulence mats (not shown) and form cooling channels 22. In the central area of ​​the bottom of each turbulence mat receiving recess 24, a coolant inlet opening 241 is provided, through which coolant from an inlet channel 201 arranged in the coolant guide housing 20 can flow into the turbulence mat receiving recess 24 and thus into the cooling channel 22.During operation, the coolant flows through the turbulence mat and exits the turbulence mat receiving recess 24 via coolant outlet openings 242, which are designed here as open sides of the turbulence mat receiving recesses 24, thus entering a drain channel 202 arranged in the coolant guide housing 20. Preferably, the cover plate 16 consists of a thin-walled aluminum sheet, which is joined to the coolant guide housing 20, preferably also made of aluminum, by brazing at 600 °C. The assembled coolant guide housing 20 with cover plate 16 can therefore be manufactured from a few, cost-effective individual components.

[0031] In Fig. Figure 4 shows the inventive step for producing a cooling arrangement according to the invention, in which the turbulence mat 18 is made of Fig. 2 on the second side 142 of the cooling channel cover 14 from Fig. 1 is fixed by means of laser welding. For this purpose, the turbulence mat 18 is placed on the second side 142 of the cooling channel cover 14 at a cooling position 143. The undersides of the wave troughs of the turbulence mat 18 contact the second side 142 of the cooling channel cover 14. The turbulence mat 18 is fixed to the cooling channel cover 14 by melting the described contact points highly locally using a laser beam, so that after cooling a metallurgical bond is formed between the two components.

[0032] Fig. Figure 5 shows the installation of the cooling channel cover 14. Fig. 4 onto the cover plate 16 of the coolant guide housing 20 Fig. 3a. The cooling channel cover 14 is placed with its second side 142 onto the cover plate 16 of the coolant guide housing 20 such that the turbulence mats 18 fixed to the cooling channel cover 14 project into the corresponding turbulence mat receiving recesses 24. For optimal cooling effect, the turbulence mats 18 are ideally dimensioned so that, when the cooling channel cover 14 is placed on the cover plate 16, they rest against the bottom of their respective assigned turbulence mat receiving recesses 24. No material-bonded connections are formed between the turbulence mats 18 and the bottoms 243 of the turbulence mat receiving recesses 24, because even with the turbulence mats 18 fixed on only the warmer side, sufficient mechanical stability of the cooling arrangement is achieved.

[0033] In Fig. 6 is the laser welding of the cooling channel cover 14 with the cover plate 16 of the coolant guide housing 20 made of Fig. 5 is shown around its circumference. This creates a fluid-tight connection between the cooling channel cover 14 and the cover plate 16.

[0034] Fig.Figure 7 shows the optional, but preferred, manufacturing step in which the cooling channel cover 14 is welded, in particular by laser welding, to the cover plate 16 of the coolant guide housing 20 at material-bonded connection points 26 around its circumference. This gives the entire cooling assembly 10 greater mechanical stability. The material-bonded connection points 26, designed here as openings, are spaced from the outer edge of the cooling channel cover 14 and are located outside the cooling positions 143 where the electronic components 12 are mounted. The openings 26 are laser-welded to the cover plate 16 on their inner circumference 261, forming fine weld seams.Joining the components by means of laser welding allows the use of thin-walled sheets for the cooling channel cover 14 and the cover plate 16 of the coolant guide housing 20, so that a cooling arrangement 20 with an improved cooling effect is obtained.

[0035] Overall, the inventive method for manufacturing a cooling arrangement 10 represents a particularly simple and cost-effective method in which the thermally sensitive electronic components 12 fixed to the cooling channel cover 14 do not suffer any heat-related damage due to the highly localized effect of the laser welding. At the same time, the laser-welded joints are particularly robust against high temperatures and mechanical stresses.

[0036] Naturally, the embodiments discussed in the detailed description and shown in the figures represent only illustrative examples of the present invention. In light of this disclosure, a wide range of possible variations is available to the person skilled in the art. Reference symbol list 10 Cooling arrangement 12 electronic components 14 Cooling channel cover 141 first page of 14 142 second page of 14 143 Cooling position 16 Cover plate 18 Turbulence mat 20 Coolant guide housings 201 Inlet channel 202 Drainage channel 22 Cooling channel 24 Turbulence mat intake recesses 241 Coolant inlet opening 242 Coolant outlet opening 243 floor of 24 26 material bonding points 261 Inner circumference of 26

Claims

[1] Cooling arrangement (10) for cooling electronic components (12) of a motor vehicle, comprising - a plate-like cooling channel cover (14), on the first side (141) of which an electronic component (12) to be cooled is fixed in thermal contact at a cooling position (143), and on the second side (142) opposite the first side (141) in the area of ​​the cooling position (143) a turbulence mat (18) is fixed in a materially bonded manner, - and a coolant guide housing (20) in which an inlet channel (201) and outlet channel (202) through which a coolant can flow are arranged, and whose cover plate (16) which is fluid-tightly connected to the second side (142) of the cooling channel cover (14) has a turbulence mat receiving recess (24) forming a cooling channel (22), which is flow-connected to the inlet channel (201) via a coolant inlet opening (241) and to the outlet channel (202) via a coolant outlet opening (242), and into which the turbulence mat (18) is inserted, characterized by , that the turbulence mat (18) is laser-welded on one side to the cooling channel cover (14), while it projects into the bottom of the turbulence mat receiving recess (24) without forming a material-bonded connection with it, wherein the cooling channel cover (14) is laser-welded on the circumference of its second side (142) to the cover plate (16) of the coolant guide housing (20). [2] Cooling arrangement (10) according to claim 1, characterized by , that the turbulence mat (18) lies against the bottom (243) of the turbulence mat receiving recess (24). [3] Cooling arrangement (10) according to one of the preceding claims, characterized by , the cooling channel cover (14) has material-bonded connection points (26) on its second side (142) spaced apart from its outer edge and outside the cooling position (143), where it is additionally connected to the cover plate (16) of the coolant guide housing (20) in a material-bonded manner. [4] Cooling arrangement (10) according to claim 3, characterized by , that the cooling channel cover (14) is welded, in particular laser welded, to the cover plate (16) of the coolant guide housing (20) at the material connection points (26). [5] Cooling arrangement (10) according to claim 4, characterized by, that the material bonding points (26) are designed as openings in the cooling channel cover (14), on the inner circumference (261) of which the cooling channel cover (14) is welded to the cover plate (16) of the coolant guide housing (20), in particular by laser welding. [6] Method for manufacturing a cooling arrangement (10) for cooling electronic components (12) of a motor vehicle, comprising the following steps: - Providing a plate-like cooling channel cover (14) on the first side (141) of which an electronic component (12) to be cooled is fixed in thermal contact at a cooling position (143), - Providing a turbulence mat (18), - Providing a coolant guide housing (20) open on the lid side, in which an inlet channel (201) and outlet channel (202) through which a coolant can flow are arranged, - Providing a cover plate (16) for the coolant guide housing (20) which has a turbulence mat receiving recess (24) forming a cooling channel (22) with a coolant inlet opening (241) for flow connection with the inlet channel (201) and a coolant outlet opening (242) for flow connection with the outlet channel (202), - Fabric-bonded fixing of the turbulence mat (18) to the second side (142) of the cooling channel cover (14) opposite the first side (141) in the area of ​​the cooling position (143), characterized by, that the turbulence mat (18) is fixed to the cooling channel cover (14) by means of laser welding, and the cover plate (16) is fixed to the coolant guide housing (20) in a manner that closes the cover side, before the cooling channel cover (14) is then placed on the cover plate (16) of the coolant guide housing (20) in such a way that the turbulence mat (18) fixed to the cooling channel cover (14) projects into the bottom of the turbulence mat receiving recess (24) without forming a material connection with it, whereupon the cooling channel cover (14) is fluid-tightly connected to the cover plate (16) of the coolant guide housing (20) by means of laser welding on the circumference of its second side (142). [7] Method according to claim 6, characterized by, that a turbulence mat (18) is used which is dimensioned so that, after the cooling channel cover (14) is placed on the cover plate (16), it rests on the bottom (243) of the turbulence mat receiving recess (24). [8] Method according to claim 6 or 7, characterized by , that the cooling channel cover (14) is additionally bonded to the cover plate (16) of the coolant guide housing (20) at point connections (26) which are arranged on its second side (142) spaced apart from its outer edge and outside the cooling position (143). [9] Method according to claim 8, characterized by , that the cooling channel cover (14) is welded, in particular laser welded, to the cover plate (16) of the coolant guide housing (20) at the material connection points (26). [10] Method according to claim 9, characterized by, that the cooling channel cover (14) has material-bonded connection points (26) formed as openings, on the inner circumference (261) of which the cooling channel cover (14) is welded to the cover plate (16) of the coolant guide housing (20), in particular by laser welding.

Images