Cooler arrangement and method for producing same

Abstract

The present invention relates to a cooler arrangement of electronic power elements, comprising a cooler housing (10), in which at least one continuous recess (13) is formed, the cooler housing (10) defining a cooling channel (17), and the cooler housing (10) being made of plastic, and a metal heat sink (2) which is located in the recess (13) of the cooler housing (10), a fluid-tight connection being formed between the heat sink (2) and the cooler housing (10).

Description

[0001] R.411508

[0002] - 1 -

[0003] Description

[0004] title

[0005] Cooler arrangement and method for its manufacture

[0006] State of the art

[0007] The present invention relates to a cooler arrangement for power electronics and a method for manufacturing the cooler arrangement.

[0008] Power semiconductors in power electronics carry high electrical currents. Together with switching losses, the resulting conduction losses are responsible for high heat dissipation, which must be dissipated from a very small area. The maximum permissible semiconductor temperature is critical for failure, which is why minimizing the thermal resistance between the semiconductor and the coolant is of central importance. For efficient cooling, the power substrates are applied to fluid-flowable heat sinks. To achieve low thermal resistance between a power substrate, especially an AMB / DBC power substrate (AMB: active metal braze; DBC: direct copper bonding), and the heat sink, the power substrate is bonded to the heat sink using a soft soldering process, or optionally a sintering process.In automotive engineering, aluminum coolers, also known as AlSiC or copper coolers, which consist of several components joined by a hard soldering process, are commonly used.

[0009] The same material is typically used for the entire cooler assembly. Such a cooler assembly with a periodically repeating wave profile is known from DE 102021 211 544 A1.

[0010] Disclosure of the invention R.411508

[0011] -2 -

[0012] In contrast, the cooling arrangement according to the invention for power electronics with the features of claim 1 has the advantage that the cooling arrangement can be optimally designed for the heat dissipation of the power electronics. For this purpose, the cooling arrangement comprises two different materials. The cooling arrangement can nevertheless provide a simple and cost-effective design. The cooling arrangement includes a heat sink made of metal, in particular copper, which ensures optimal heat transfer and can dissipate heat to a fluid-flowing cooling channel. The cooling channel is formed in a cooling housing. The cooling housing is made of plastic. Thus, the cooling arrangement according to the invention comprises a cooling housing made of plastic and a heat sink made of metal. The cooling housing has a recess extending through one wall of the cooling housing, in which the metal heat sink is arranged.A fluid-tight connection, in particular a direct metal-plastic connection, is formed between the heat sink and the cooler housing. The heat sink thus covers the recess in the cooler housing in a fluid-tight manner and forms part of the cooling channel, with the heat sink coming into contact with the fluid flowing through the cooling channel.

[0013] The dependent claims describe preferred embodiments of the invention.

[0014] Preferably, a direct metal-plastic connection is formed between the heat sink and the plastic cooler housing, with structures on the surfaces of the metal and the plastic to be joined. These surfaces preferably have protrusions and recesses, which are joined in particular by pressing them together with and / or without heat input.

[0015] Preferably, undercuts are also provided on the surfaces, resulting in a particularly good, form-fitting direct metal-plastic connection. This direct metal-plastic connection is preferably created by locally melting the plastic and diffusing the melt into a pre-structured metallic surface. The pre-structuring is particularly preferably carried out using a laser beam.

[0016] The cooler housing preferably comprises a base body and a cover. The base body and the cover are both made of plastic and connected by a R.411508

[0017] - 3 -

[0018] The components are connected by a fluid-tight connection, in particular a welded joint. The welded joint can be produced by plastic welding, preferably using a laser. Alternatively, the cooler housing is formed in one piece.

[0019] The cooler housing preferably has an inlet and an outlet. The inlet and outlet are also made of plastic. Preferably, the inlet and outlet are located on the same side of the cooler housing. If the cooler housing is a two-part design with a base and a cover, the inlet and outlet are preferably located together on one of the two components, i.e., the base or the cover.

[0020] The heat sink is preferably made entirely of copper. Alternatively, the heat sink is made of aluminum or of a composite material comprising copper and aluminum.

[0021] The metallic heat sink preferably has cooling elements, in particular fins or pins or the like, which project into the cooling channel when assembled. The heat sink or a cooling element is or comprises preferably an extrusion, in particular a pin-fin component, or a stamped-bent part, in particular a strip-fin component, or a periodically repeating wave profile. The heat sink is preferably supplied as a single piece, but can also be manufactured from several parts, which are joined together, for example, by solder joints, in particular brazing joints.

[0022] The cooler assembly preferably comprises a metallic frame positioned between the heat sink and the cooler housing. The metallic frame preferably has a width sufficient to ensure a secure, fluid-tight connection to both the cooler housing and the heat sink. A direct metal-to-plastic connection is formed between the metallic frame and the cooler housing, and a fluid-tight connection, in particular a metal-to-metal weld, is established between the heat sink and the metallic frame. Thus, an indirect, fluid-tight connection is formed between the cooler housing and the heat sink via the metallic frame. R.411508

[0023] - 4 -

[0024] Preferably, the metallic frame is an insert that is connected to the plastic radiator housing during the manufacturing process. The radiator housing is preferably an injection-molded component. The frame is preferably made of the same material as the metallic heat sink.

[0025] Preferably, the inlet and outlet ports are arranged diagonally opposite each other on the radiator housing. This allows for the longest possible cooling path through the radiator housing.

[0026] To reinforce the plastic cooler housing, metallic inserts are preferably integrated into the cooler housing. These can, for example, be easily integrated into the cooler housing using injection molding.

[0027] Preferably, the cooler housing and / or the heat sink has a structured surface at the fluid-tight connection to the other component, such that recesses, particularly recesses in the metallic heat sink, are preferably formed. During the fixing process, e.g., using a laser, the plastic cooler housing melts at least partially at the area intended for connection to the heat sink, allowing the plastic to enter the recesses and create a positive-locking connection between the metallic heat sink and the plastic cooler housing. Preferably, the recesses are provided with undercuts, thus enabling a particularly secure and fluid-tight positive-locking connection between the heat sink and the cooler housing.

[0028] To enable secure and easy attachment of the power electronics to the cooling assembly, the heat sink preferably has a connection surface for the power electronics. This connection surface is preferably the side of the heat sink facing away from the cooling channel. Preferably, a substrate is applied to the connection surface.

[0029] Preferably, the heat sink has a nickel-containing layer on all areas facing the cooling channel and coming into contact with the cooling fluid. The nickel-containing layer is preferably R.411508.

[0030] -5 -

[0031] Coating or a mechanically applied layer, e.g. by roller cladding.

[0032] Preferably, the heat sink has a circumferential rim with which the heat sink rests on the outside of the cooler housing.

[0033] Furthermore, the present invention relates to a method for manufacturing a cooling arrangement for power electronics. The method comprises the following steps:

[0034] - Providing a plastic cooler housing, wherein at least one recess is formed through a wall area of ​​the cooler housing, and wherein the cooler housing defines a cooling channel,

[0035] - Arranging a metal heat sink in the recess of the cooler housing such that the heat sink closes the recess, wherein the heat sink preferably has a rim which rests on an outer surface of the cooler housing and cooling elements, in particular fins or pins, protrude through the recess into the cooling channel, and

[0036] - Establishing a fluid-tight connection between the heat sink and the cooler housing, in particular a direct metal-plastic connection.

[0037] Preferably, the cooler housing is designed in two parts, consisting of a base body and a cover. In a first step, the heat sink is connected to the cover, which has the recess, to create a direct metal-plastic connection. In a second step, the base body is then connected to the cover, which contains the heat sink, in particular by means of a plastic weld.

[0038] Preferably, the cooler housing is an injection-molded component, in particular with metallic inserts to reinforce the cooler housing.

[0039] Preferably, all surfaces of the cooling element which are arranged in the cooling channel in the assembled state and come into contact with a cooling fluid flowing through the cooling channel have a nickel-containing layer.

[0040] Brief description of the drawings R.411508

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[0042] Preferred embodiments of the invention are described in detail below with reference to the accompanying drawing. The drawing shows:

[0043] Figure 1 shows a schematic, perspective sectional view of a cooler arrangement according to a first preferred embodiment of the invention in exploded view.

[0044] Figure 2 shows a schematic, perspective view of the cooler arrangement from Figure 1.

[0045] Figure 3 shows a schematic, perspective view of a cooler arrangement according to a second embodiment in exploded view.

[0046] Figure 4 shows a schematic, perspective view of a cooler arrangement according to a third embodiment in exploded view.

[0047] Figure 5 shows a schematic, perspective view of a cooler arrangement according to a fourth embodiment of the invention and

[0048] Figure 6 shows a schematic, perspective view of a fluid flow through the cooler arrangement of Figure 5.

[0049] Preferred embodiments of the invention

[0050] A cooler arrangement 1 according to a first preferred embodiment of the invention is described in detail below with reference to Figures 1 and 2.

[0051] As can be seen from Figures 1 and 2, the cooler arrangement 1 comprises a cooler housing 10 and three heat sinks 2.R.411508

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[0053] The cooler housing 10 is made of plastic. As can be seen in particular from Figures 1 and 2, the cooler housing 10 is made in two parts with a base body 11 and a cover 12.

[0054] The base body 11 and the lid 12 are injection-molded plastic components which are joined together in a fluid-tight manner, in particular by means of a plastic welding connection 16.

[0055] As can be seen from Figures 1 and 2, three recesses 13 are provided on the lid 12, which are designed as through openings in the lid 12.

[0056] The cooler housing 10 further comprises an inlet port 14 and an outlet port 15. The inlet port 14 and the outlet port 15 are both arranged on the base body 11 and are integrally formed with the base body 11, which is made of plastic. As can be seen from Figure 1, the three heat sinks are made entirely of metal, in particular copper. Each heat sink 2 is arranged in one of the recesses 13 in the cover 12.

[0057] The cooler assembly 1 further comprises three frames 22. The frames 22 are arranged between the cover 12 and the heat sink 2. The frames 22 are optional. They enable precise and localized heat input for the direct metal-plastic connection. The heat sinks 2 are then fluid-tightly fixed to the frames 22 by means of a laser welding connection.

[0058] The heat sinks 2 each have a base plate 20 and a plurality of projecting cooling elements 21. In this embodiment, the projecting cooling elements 21 are pins that protrude into a cooling channel 17 in the cooler housing 10. The direction of flow through the cooling channel 17 is indicated in Figure 1 by the arrows 5.

[0059] Each heat sink 2 has a circumferential rim 23 with which the heat sink 2 rests on the frame 22. This ensures a secure welded connection between the heat sink 2 and the frame 22.

[0060] secured.R.411508

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[0062] The base plate 20 has a connection surface 24 on its outer side. This surface 24 is designed to attach power electronics (not shown) to the heat sink 2. A single power electronics unit can be attached to each heat sink 2, or a power electronics unit spanning all three heat sinks 2 can be attached to them. A substrate can be applied to the connection surface 24, for example, to ensure secure attachment of the power electronics unit.

[0063] Figure 1 schematically illustrates the flow through the cooler assembly 1. Arrow 6 indicates the inflow of a cooling fluid into the cooler assembly. The cooling fluid enters the cooler assembly via the inlet nozzle 14, is deflected by 90°, and then flows through the cooling channel 17 (arrows 5). At the outlet nozzle 15, the cooling fluid is deflected again by 90° and then flows out of the cooler assembly 1 (arrow 7).

[0064] As the cooling fluid flows through the cooling channel 17, it comes into contact with the protruding cooling elements 21 and carries away heat that has been transferred from the power electronics to the heat sinks 2. This ensures that the power electronics are reliably cooled.

[0065] Since the cooler housing 10, including the inlet nozzle 14 and the outlet nozzle 15, is made entirely of plastic, the cooler assembly 1 can be manufactured very cost-effectively. Only the heat sinks 2, which are preferably made of copper, and the frames 22, which enable an improved connection to the cooler housing 10, are metallic components with somewhat higher material costs.

[0066] To manufacture the cooler assembly 1, the two parts of the cooler housing 10, i.e., the base body 11 and the cover 12, can be produced separately as injection-molded plastic components. The metal frames 22 serve as insert components, which together with the cover 12 form a subassembly. A direct metal-plastic connection is formed between the metal frames and the cooler housing 10. The heat sinks 2 can then be attached using an R.411508

[0067] - 9 -

[0068] The welded connection is securely and fluid-tightly connected to the frame 22. This further sub-assembly can then be connected to the base body 11 at the cover 12 by means of a plastic welding process. The base body 11 and the cover 12 are preferably made of the same plastic material.

[0069] Thus, a cost-effective cooler assembly 1 can be provided, with the use of metallic heat sinks 2 enabling very good thermal heat dissipation to a cooling fluid. The metallic heat sink 2 is integrated into a plastic cooler housing 10, which can be manufactured very cost-effectively as an injection-molded component. Furthermore, the weight of the cooler assembly can be significantly reduced by using plastic.

[0070] The plastic material used is preferably PA66, polypropylene, or polyphenylene sulfide (PPS). PA66 and PPS, in particular, can withstand short-term operating temperatures up to 240°C, making this high temperature resistance of the plastic suitable for heat-intensive processes such as soldering between individual components of the heat sink 2.

[0071] Copper or aluminum is preferably used as the material for the heat sink 2.

[0072] The cost-effective design of the cooler housing 10 as an injection-molded plastic component allows for short-term design changes, for example, to meet different customer requirements. The plastic cooler housing 10 offers a high degree of design freedom for its three-dimensional shapes.

[0073] The relatively low mass of the metallic heat sinks 2 allows for precise process control to create a bond between the metal and plastic materials. This ensures a particularly high level of sealing of the cooler assembly. R.411508

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[0075] Further preferred embodiments of the invention are described below, wherein identical or functionally equivalent parts are designated with the same reference numerals as in the first embodiment.

[0076] Figure 3 shows a cooler arrangement 1 of a second embodiment. Here, the cooler housing 10' is designed as a single-piece component. This can be achieved, for example, by injection molding. An inlet nozzle 14 and an outlet nozzle 15 are also formed integrally with the plastic cooler housing 10. As in the first embodiment, recesses 13 are provided in the cooler housing 10, into which metallic heat sinks 2 are inserted. The heat sinks 2 are then joined to the single-piece cooler housing 10' by means of a direct metal-plastic connection, thus enabling a secure and fluid-tight direct metal-plastic connection between the heat sinks 2 and the cooler housing 10'.

[0077] Figure 4 shows a third embodiment, which also has a one-piece cooler housing 10'. This cooler housing 10' is also manufactured by plastic core injection molding, including inlet nozzles 14 and outlet nozzles 15. In the embodiment shown in Figure 4, a single recess 13 is formed in the cooler housing 10', into which a single heat sink 2 is inserted and connected to the cooler housing 10'. As in the first embodiment, a frame 22 is used. The heat sink 2 is made of aluminum and has a copper coating 2' or roll-clad copper for connecting the power electronics.

[0078] Figures 5 and 6 show a fourth embodiment of the invention, wherein the cooler housing 10 of the fourth embodiment is again designed in two parts. The fourth embodiment demonstrates a design freedom of the cooler arrangement 1. As can be seen from Figure 6, the inlet nozzle 14 and the outlet nozzle 15 are arranged diagonally opposite each other on the cooler housing 10. Flow through the cooling channel 17 enables parallel flow to the three heat sinks 2. This allows three power electronics to be supplied with the same cooling capacity simultaneously. A distribution channel 30 and a collecting channel 31 are thus formed in the plastic cooler housing 10, which run along a longitudinal direction of the cooler arrangement 1. Between the metallic heat sink 2 and the R.411508

[0079] - 11 -

[0080] The cooler housing 10, made of plastic, is in turn a direct metal-plastic connection.

Claims

R.411508 - 12 - Claims 1. Cooling arrangement of a power electronics unit, comprising a cooler housing (10) in which at least one continuous recess (13) is formed, wherein the cooler housing (10) defines a cooling channel (17), wherein the cooler housing (10) is made of plastic, and a metal heat sink (2) which is arranged in the recess (13) of the cooler housing (10), wherein a fluid-tight connection is formed between the heat sink (2) and the cooler housing (10).

2. Cooler arrangement according to claim 1, wherein a direct metal-plastic connection is formed between the heat sink (2) and the cooler housing (10).

3. Cooler arrangement according to one of the preceding claims, wherein the cooler housing (10) has a base body (11) and a cover (12) which are connected to each other by means of a fluid-tight connection or wherein the cooler housing (10') is formed in one piece.

4. Cooler arrangement according to one of the preceding claims, wherein the cooler housing (10) has an inlet nozzle (14) and an outlet nozzle (15) which are formed integrally with the cooler housing (10).

5. Cooler arrangement according to one of the preceding claims, wherein the heat sink (2) is made of copper or of aluminum or of a composite material of copper and aluminum.

6. Cooler arrangement according to one of the preceding claims, wherein the metal heat sink (2) is an extrusion component, in particular a pin-fin component, or wherein the metal heat sink (2) is an R.411508 - 13 - A stamped and bent component, in particular a strip-fin component or a periodically repeating wave profile.

7. Cooler arrangement according to one of claims 1 or 3 to 6, further comprising a metallic frame (22) which is arranged between the heat sink (2) and the cooler housing (10), wherein a direct metal-plastic connection is formed between the metallic frame (22) and the cooler housing (10) and a fluid-tight connection is formed between the heat sink (2) and the metallic frame.

8. Cooler arrangement according to claim 7, wherein the metallic frame (22) is made of the same metallic material as the heat sink (2).

9. Cooler arrangement according to one of claims 4 to 8, wherein the inlet nozzle (14) and the outlet nozzle (15) are arranged diagonally opposite each other on the cooler housing (10).

10. Cooler arrangement according to one of the preceding claims, wherein the cooler housing (10) has metallic inserts for stabilizing the cooler housing (10).

11. Method for manufacturing a cooling assembly (1) for power electronics, comprising the steps: Providing a cooler housing (10) made of plastic, defining a cooling channel (17) and in which at least one recess (13) is formed; arranging a heat sink (2) made of metal in the recess (13) such that the heat sink (2) seals the recess (13) in a fluid-tight manner, in particular with an edge (23) of the heat sink (2) on an outer surface of the cooler housing (10), wherein cooling elements (21) of the heat sink (2) project into the cooling channel (17); and Establishing a fluid-tight connection between the heat sink (2) and the cooler housing (10), in particular a direct metal-plastic connection.

12. Method according to claim 11, wherein the cooler housing (10) is in two parts with a base body (11) and a recess (13) R.411508 - 14 - The lid (12) is manufactured and in a first step the heat sink (2) is connected to the lid (12) and in a second step the base body (11) is connected to the lid (12) having the heat sink (2).

13. Method according to claim 11 or 12, wherein all surfaces of the cooling element (2) which are arranged in the cooling channel (17) in the assembled state and come into contact with the cooling fluid flowing through the cooling channel (17) have a nickel-containing layer.

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