Particle-resistant design of an electronics cooler with a central collecting channel

Abstract

The present invention relates to a cooler for cooling, preferably of a power electronics component, comprising: a deep-drawn part with a flow channel for a cooling fluid, in particular a cooling liquid, and a turbulator with a periodically alternating structure, wherein the turbulator is arranged in the flow channel, preferably constructed in the form of microchannels, and wherein a central collecting channel is arranged in the channel-forming deep-drawn part below the turbulator.

Description

State of the art

[0001] The present invention relates to a cooler for cooling an electronic component, preferably a power electronic component, and to an electronic assembly with a cooled electronic component, preferably a power electronic component.

[0002] 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 small area using a cooling system. The maximum permissible semiconductor temperature is critical for failure, making minimizing the thermal resistance between the semiconductor and the coolant of paramount importance. For efficient cooling, power substrates are applied to high-performance coolers. These coolers are made of aluminum-AlSiC or copper alloys. Inside the cooler, pins or fins are arranged to increase the heat-transferring surface area and enhance heat transfer. To minimize thermal resistance between the AMB / DBC power substrate and the cooler, the power substrate is bonded to the cooler using a soft soldering process, or optionally, a sintering process.These coolers may also have a surface coating made of materials suitable for a soft soldering process or a sintering process.

[0003] In automotive engineering, aluminum coolers, also known as AlSiC or copper coolers, which can consist of several components joined by a brazing process, are common.

[0004] Coolant coolers often utilize fins (turbulators) made from stamped sheet metal. Their thermal performance is primarily determined by the heat transfer between the fluid and the fin surface, the fin surface area, and the fin efficiency. Suitable fins, in particular, possess a high heat transfer coefficient, which can be achieved, among other things, by minimizing the clear spacing between the fins perpendicular to the flow direction. However, this often conflicts with the requirement for the coolant circuit to be robust against contamination in the form of particles up to a certain size. A standard requirement for a cooling channel is 600-100 µm particles. The smaller the clear spacing between the fins perpendicular to the flow direction, the more readily particles accumulate in front of the fins, and the geometry can gradually become clogged.This leads to a blockage of the cooling channel in the long term, significantly restricting or preventing the cooler's function. Therefore, in current cooler designs, the clear distance between the cooling fins is chosen so that even the largest expected particles in the cooling circuit can still pass through the fin structure. Nevertheless, the maximum achievable cooler performance is thus again largely dependent on the expected particle sizes in the cooling circuit. A desirable solution would therefore be a coolant cooler design that, despite high thermal performance, is robust against a preferably defined particle load and is therefore particularly suitable for use in power electronics applications where this robustness is required. Disclosure of the invention

[0005] The cooler according to the invention with the features of claim 1 and the electronic assembly according to the invention with the features of claim 10 have the advantage that, while maintaining high thermal performance, robustness against particles in the cooling circuit can still be achieved, so that the cooler according to the invention and the electronic assembly according to the invention are particularly well suited for use in power electronic applications.

[0006] A particular advantage of the invention can be seen in the fact that providing a preferably defined bypass on one side of the flow channel represents a simple solution to the aforementioned disadvantages of the prior art, which can also be manufactured cost-effectively.

[0007] According to the invention, this is achieved by the cooler comprising a deep-drawn part with a flow channel for a cooling fluid, in particular a coolant. Furthermore, the cooler includes a turbulator with a periodically alternating structure. The turbulator is arranged in the flow channel and preferably has a plurality of microchannels. Additionally, a central collection channel for particles and similar solids is arranged in the flow channel of the deep-drawn part below the turbulator. The collection channel is preferably arranged centrally in the flow channel and allows a bypass for particles that have a larger cross-section than the maximum cross-sectional width of the turbulator. This allows the particles to bypass the turbulator via the collection channel and prevents them from clogging the inlet areas of the turbulator.

[0008] Because the cross-section of the central collecting channel is larger than the largest expected particles in the cooling medium, the advantage is that the particles can pass through the cooling channel via this collecting channel or central bypass without clogging one side of the turbulator.

[0009] The dependent claims describe preferred embodiments of the invention.

[0010] In a further preferred embodiment, in order to selectively divert the particles past the microchannels into the collecting channel, the turbulator on the cooling fluid inlet side can be designed in a V-shape in the direction of the collecting channel.

[0011] In a particularly preferred embodiment, the angle 'a' of the V-cutout can optimally lie between 30° and 60°.

[0012] In further preferred embodiments, the collecting channel can be imprinted over the entire channel length or only overlapping over the length of the turbulator.

[0013] Preferably, the overlapping collecting channel is designed along the length of the turbulator such that an inlet-side end and an outlet-side end of the collecting channel are freely exposed in the flow channel. This allows particles to be easily introduced into the collecting channel undisturbed, guided past the turbulator, and exit into the flow channel at the outlet-side end of the collecting channel.

[0014] It is particularly advantageous to have the tip of the turbulator's V-shaped cutout at the inlet and the collecting channel arranged on a central axis of the cooler. This allows particles with an excessively large cross-section to be transported along the two legs of the V-cutout towards its tip, where they enter the collecting channel and are guided past the turbulator. Brief description of the drawings Fig. 1 a perspective view of an electronic assembly according to a first embodiment of the invention, Fig. 2 a schematic sectional view of the electronic assembly with a cooler according to the first embodiment, Fig. 3 a top view of the cooler with a turbulator according to the first embodiment, Fig. 4 one essentially the Fig. 2. A corresponding representation of a part of the electronic assembly to define a detail, and Fig. 5 an enlarged view of the detail of Fig. 4. Embodiments of the invention

[0015] Preferably, all identical components, elements, and / or units in all figures are designated with the same reference numerals. The following refers to the... Fig. 1 to 5 describe a cooler 12 and an electronics assembly 14.

[0016] Fig. Figure 1 shows the electronic assembly 14 with three electronic components or power modules arranged in parallel to each other, which are preferably designed as power electronic components 1. The power electronic components 1 of this embodiment are arranged on the cooler 12 via an intermediate layer or upper plate 2. On the side opposite the power electronic components 1, the cooler 12 has a fluid inlet 13 and a fluid outlet 5, so that a cooling fluid, preferably coolant, can flow from the cooling fluid inlet 13 to the cooling fluid outlet 5 through the cooler 12 to dissipate heat from the electronic components 1.

[0017] Accordingly, the basis for the invention is the one in Fig. 1 cooler 12 shown, which is made up of at least three parts, comprising the upper plate 2, a deep-drawn part 3, a turbulator 4 and in particular the cooling fluid inlet 13 and the cooling fluid outlet 5 or coolant nozzle.

[0018] These components are preferably joined by means of a brazing process to the one described in Fig. 1 The cooler 12, which is shown schematically simplified in its entirety, is connected to each other.

[0019] The brazing alloy layer is located between each of the aforementioned parts. As mentioned, cooler 12 can be used in Fig. The coolant nozzles shown in Figure 1 are arranged perpendicular to the flow direction through the cooler 12. These components can also be joined using a hard solder in the same manufacturing step, which offers the advantage of a simplified manufacturing process.

[0020] The one inside, made of Fig. The turbulator 4, as shown in Figure 2, serves as a surface-enlarging, flow-guiding, and heat-transfer-enhancing structure. This turbulator 4 can also be joined to the other previously described components via a brazing process. The turbulator 4 can be made of aluminum or another material with higher thermal conductivity and / or be coated. On the outside, above the turbulator, are the components, which together consist of... Fig. 1 visible power modules arranged, which contain the power semiconductors to be cooled.

[0021] The cooler 12 carries a coolant for heat dissipation and / or cooling of the power modules or power electronic components 1. These power electronic components 1 can be attached to the cooler 12 by a soft soldering process or a sintering process. The cooler 12 can be fitted with power modules on one or both sides.

[0022] The Turbulator 4, as can be seen in particular from Fig. As can be seen in section 2, this represents an internal structure of the overall arrangement. The information from Fig. 2 and in particular from the enlarged representation of the Fig. The five visible fins, or cooling fins, can be made of aluminum or another material with good thermal conductivity and formability. The structure is created using a stamping or roll forming process to achieve ideal surface utilization and maximum fin efficiency. The fin structure depends on the required heat dissipation. To achieve the largest possible fin surface area for high cooling performance, the spacing x perpendicular to the flow direction between the individual fins 9 is kept as small as possible to create as many narrow microchannels as possible.

[0023] In detail, for ideal geometry in power electronics applications, the spacing (width) x of the microchannels should be less than 1 mm or less than 4 times the turbulator wall thickness. To prevent the microchannels from becoming clogged with particles larger than x from the cooling circuit during operation, a central collecting channel 8 is formed below the turbulator 4. The width and cross-section of this collecting channel 8 are adapted to the largest expected particles.

[0024] The collecting channel 8 can be embossed along the entire length of the flow channel or only overlapping the length of the turbulator 4. To guide the particles past the microchannels in the coolant flow towards the collecting channel 8, the turbulator 4 can additionally be V-shaped on the coolant inlet side, extending towards the collecting channel 8. The angle α of the V-shaped cutout 10 can be between 30° and 60°.

[0025] As especially from Fig. As can be seen in Figure 3, the collecting channel 8 and a tip 20 of the V-cutout 10 lie together on a central axis XX.

[0026] An inlet-side end of the collecting channel 8 is exposed to the flow channel 11 and is not covered by the turbulator. Likewise, an outlet-side end of the collecting channel 8 is exposed to the flow channel 11 and is not covered by the turbulator 4. Preferably, the overhang of the collecting channel 8 at the inlet-side and outlet-side ends is the same and is approximately half the diameter of the fluid inlet 13 and the fluid outlet 5.

[0027] If particles with a cross-section larger than the maximum spacing x of the microchannels of the turbulator 4 flow through the fluid inlet 13 towards the turbulator, they are transported by the flow pressure over the two legs of the V-shaped cutout 10 towards the apex 20 of the V-shaped cutout. This is in Fig. 3 schematically indicated by arrows A. The oversized particles can then flow into the collecting channel 8 at the inlet end and be guided past the turbulator 4 below it. At the outlet end of the collecting channel 8, the oversized particles then exit the collecting channel 8 and enter the flow channel 11, where they are carried away via the fluid outlet 5.

[0028] Thus, the cooler according to the invention is very robust against impurities, and clogging of the turbulator at the inlet end can be prevented. As a result, the cooler can provide very good cooling performance throughout its service life.

Claims

[1] Cooler for cooling an electronic component, preferably a power electronic component (1) comprising: - a deep-drawn part (3) with a flow channel (11) for a cooling fluid, in particular a cooling liquid, and - a turbulator (4) with a periodically alternating structure, - wherein the turbulator (4) is arranged in the flow channel (11), preferably constructed in the form of microchannels, and - wherein a central collecting channel (8) is arranged in the channel-shaped deep-drawn part (3) below the turbulator (4). [2] Cooler according to claim 1, wherein the turbulator (4) is V-shaped on the cooling fluid inlet side with a V-cutout (10) in the direction of the collecting channel (8). [3] Cooler according to claim 2, wherein an angle a of the V-cutout (10) is between 30° and 60°. [4] Cooler according to one of claims 1 to 3, wherein the collecting channel (8) extends over the entire channel length of the flow channel (11). [5] Cooler according to one of claims 1 to 3, wherein the collecting channel (8) extends only overlapping over the length (6) of the turbulator (5). [6] Cooler according to one of claims 2 to 5, wherein a tip (20) of the V-cut (10) and the collecting channel (8) are arranged on a central axis (XX) of the cooler. [7] Electronic assembly comprising an electronic component (1), in particular a power electronic component, and a cooler (12) according to any of the preceding claims.

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