Power electronic system with a switching device and a liquid cooling device

Abstract

Power electronic system (1) with a switching device (2) and with a liquid cooling device (3), wherein the switching device (2) has a plate element (20) on the side of which facing away from the liquid cooling device (3) power semiconductor components (222) are arranged on electrically insulated conductor tracks (220) and are connected in a circuit-appropriate manner by means of a connecting device (224), wherein the liquid cooling device (3) has a first subbody (30) with an inlet volume region (34) and an outlet volume region (38) and a second subbody (32), wherein a cooling volume region (36) is formed between the two subbodies, wherein heat transfer elements (5) project from the second subbody (32) into the cooling volume region (36), wherein the second subbody (32) is arranged in a recess (306) of the first subbody (30) and the two subbodies (30, 32) are connected to each other in a materially bonded and liquid-pressure-tight manner and have a common planar first surface (300) which forms a first main surface and wherein the majority of the heat transfer bodies (5) have a rhomboid cross-section with rounded first and second corners (50, 52), wherein a long diagonal (502) extends between the two first rounded corners (50) and a short diagonal (522) extends between the two second rounded corners (52), and indented side surfaces (54), wherein the ratio of a corner radius (500) of the first corner (50) to a corner radius (520) of the second corner (52) is between 1 : 1 and 1 : 2.

Description

[0001] The invention describes a power electronic system with a liquid cooling device and with a switching device, the latter preferably being designed as a power semiconductor module.

[0002] A liquid-cooled switching device is known from the prior art, specifically disclosed in US 6,594,149 B2. This device comprises a switching module with a circuit element and a switching module base plate on which the circuit element is mounted, a switching housing for receiving the switching module, and a coolant chamber for directing a coolant into contact with the rear side of a module base plate of the switching module.

[0003] From DE 10 2020 132 689 A1, a power electronic system with a switching device and a liquid cooling device is known, wherein the switching device has a plate element on whose side facing away from the liquid cooling device power semiconductor components are arranged on electrically insulated conductor tracks and connected in a circuit-oriented manner by means of a connecting device, wherein the liquid cooling device has a first sub-body with an inlet volume region and an outlet volume region and a second sub-body, wherein a cooling volume region is formed between the two sub-bodies, wherein a plurality of heat transfer elements project from the second sub-body into the cooling volume region, wherein the second sub-body, preferably completely,is arranged in a recess of the first sub-body and the two sub-bodies are materially and liquid-pressure-tightly connected to each other and have a common flat surface which forms a first main surface and wherein the liquid cooling device is designed and provided to be supplied with a cooling liquid from the inlet volume area via the cooling volume area to the outlet volume area and wherein the plate element of the switching device is force-fitted onto the first surface.

[0004] DE 10 2017 126 716 A1 discloses an arrangement and a power semiconductor module for this purpose, which is configured with a switching device comprising a substrate, a connecting device and terminals, and with a pressure device movably arranged in the normal direction of the substrate, wherein the substrate has electrically insulated conductor tracks, wherein a power semiconductor component is arranged on a conductor track and electrically connected to it, wherein the switching device is internally connected in a circuit-oriented manner by means of the connecting device, and wherein the pressure device comprises a rigid base body, an elastic pressure body and a spring element or a plurality of spring elements.wherein the elastic pressure body projects out of the base body in the normal direction of the substrate towards the substrate and wherein the spring body is supported against an abutment that is immovable relative to the substrate and presses the pressure body in the normal direction of the substrate towards the substrate and thus indirectly or directly against the substrate and thus also against the switching device.

[0005] CN 2 13 716 889 U discloses a heat exchange structure comprising a heat-conducting plate and a plurality of fins, wherein the fins are arranged on a surface of the heat-conducting plate and connected to the heat-conducting plate, channels are formed between the fins through which coolant can flow, and the cross-sectional area of ​​the fins gradually decreases from the center of the fins to both ends. A rounded section is formed at the center of each fin, and the included angle of each end is an acute angle.

[0006] JP 2016-219 571 A discloses a liquid cooler comprising: a housing in which a coolant channel is arranged and an opening 14 is formed on an upper wall; a heat sink comprising a heat dissipation substrate arranged in the opening of the housing and soldered to the upper wall of the housing, with a first surface facing the coolant channel and a second surface serving as a clamping surface for the heating unit; and a plurality of pin fins integrally arranged on the first surface of the heat dissipation substrate and projecting into the coolant channel.

[0007] A persistent deficiency in such systems lies in the insufficient cooling capacity, whereby the energy, typically thermal, which usually results from losses in the switching device, must be dissipated to a cooling medium in order to protect the switching device from overheating and thus destruction.

[0008] In light of these circumstances, the invention aims to further develop the liquid cooling device of a power electronic system in such a way that the heat transfer from the switching device of the power electronic system to a cooling medium, more precisely to a cooling liquid, is improved.

[0009] This problem is solved according to the invention by a power electronic system with a switching device and a liquid cooling device, wherein the switching device has a plate element on whose side facing away from the liquid cooling device power semiconductor components are arranged on electrically insulated conductor tracks and are connected in a circuit-oriented manner by means of a connecting device, wherein the liquid cooling device has a first sub-body with an inlet volume region and an outlet volume region and a second sub-body, wherein a cooling volume region is formed between the two sub-bodies, wherein heat transfer elements project from the second sub-body into the cooling volume region, wherein the second sub-body is arranged in a recess of the first sub-body and the two sub-bodies are connected to each other in a materially bonded and liquid-pressure-tight manner and have a common flat first surface.which forms a first main surface, and wherein the majority of the heat transfer bodies have a rhomboid cross-section with rounded first and second corners, wherein a long diagonal extends between the two first rounded corners and a short diagonal extends between the two second rounded corners, and have indented side surfaces, wherein the ratio of a corner radius of the first corner to a corner radius of the second corner is between 1 : 1 and 1 : 2.

[0010] It is particularly preferred if the plate element of the switching device is arranged on the first surface, preferably in a force-fit manner.

[0011] It can be advantageous if individual or all heat transfer elements are in mechanical contact with a floor surface of the cooling volume area.

[0012] It may be preferred if the second sub-body has a dome extending towards the first sub-body and preferably having a blind hole with an internal thread. It may be preferred if the dome is in mechanical contact with the bottom surface of the cooling volume area or is metallurgically bonded to it. Furthermore, it may be preferred if the dome extends into the bottom surface.

[0013] It may also be preferred if the heat transfer body has a base section and a main section, and this main section preferably has a constant cross-section over its entire length. If a base section is present, the following dimensioning relationships refer to the main section of the heat transfer body.

[0014] It can be advantageous if the ratio of the short diagonal of one of the heat transfer bodies to the long diagonal of this heat transfer body is between 1 : 1.1 and 1 : 1.6, preferably between 1 : 1.2 and 1 : 1.4.

[0015] It can also be advantageous if the ratio of the corner radius of the first corner to the corner radius of the second corners is between 1 : 1.2 and 1 : 1.6.

[0016] Furthermore, it can be advantageous if the ratio of the corner radius of the second corner to a radius of indentation of one of the side faces is between 1 : 1 and 1 : 2, preferably between 1 : 1.2 and 1 : 1.6.

[0017] It may be preferred if the ratio of the shortest first distance of the heat transfer body to a nearest neighbor to the shortest second distance of the heat transfer body to a neighbor beyond the next is between 1 : 1.2 and 1 : 2, preferably between 1 : 1.4 and 1 : 1.6.

[0018] It is understood that the various embodiments of the invention can be implemented individually or in any combination to achieve improvements.

[0019] Further explanations of the invention, advantageous details and features will become apparent from the following description of the invention contained in the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6 to Fig. 7 schematically illustrated embodiments of the invention or of respective parts thereof. Fig. Figure 1 shows a section through a first embodiment of a power electronic system according to the invention. Fig. Figure 2 shows a section through a second embodiment of a power electronic system according to the invention. Fig. Figure 3 shows a view of the heat transfer elements of the second subbody of the liquid cooling device of this second embodiment. Fig. Figure 4 shows details of this heat transfer body. Fig. Figure 5 shows further details of these heat transfer bodies. Fig. Figure 6 shows a three-dimensional view of the second part of a liquid cooling device of a third embodiment of a power electronic system according to the invention. Fig. Figure 7 shows a three-dimensional view of a section through this third embodiment of this liquid cooling device.

[0020] None of the figures exhibits all the features of claim 1.

[0021] Fig. Figure 1 shows a section through a first embodiment of a power electronic system 1 according to the invention. A liquid cooling device 3 is shown, comprising a first and a second sub-body 30, 32. The first sub-body 30 has an inlet volume region 34 and an outlet volume region 38, each extending into the plane of the drawing and forming a channel therein. A cooling volume region 36 is formed between the inlet and outlet volume regions 34, 38.

[0022] To form this cooling volume region 36, the first sub-body 30 has a recess 306 in which a second sub-body 32 is arranged. This second sub-body 32 has a plate-like base shape and heat transfer elements 5 extending from it into the cooling volume region 36. The plate-like base shape forms a flat surface 320 on its side facing away from the cooling volume region 36. This flat surface 320, together with the surrounding flat surface 302 of the first sub-body 30, forms a common flat first surface 300 of the liquid cooling device 3.

[0023] In this embodiment, the plate-like base form of the second sub-body 32 rests on a contact surface of the first sub-body 30 around its entire circumference. A connecting element 4, here a hard solder 40, is located between an edge region of the second sub-body 32 and a corresponding inner edge of the first sub-body 30 – cf. Fig. 2. This arrangement ensures that the second sub-body 32 is materially bonded and liquid-pressure-tight within the recess 306, and the cooling volume area 36 is designed such that it can be permeated with cooling fluid from the inlet volume area 34 to the outlet volume area 38. The brazing alloy 40 protrudes above the first surface 300. However, it can also be recessed relative to this surface, thus forming a groove. It is particularly preferred if the brazing alloy 40 protrudes after this arrangement and is subsequently ground flush with the first surface 300 in a further manufacturing step.

[0024] As an alternative to the brazing connection 40, the metallurgical connection between the first and second sub-body 30, 32 can also be formed as a welded connection. In the case of a preferred laser welded connection, no explicit connecting element is provided.

[0025] On the partial surface 320 of the second partial body 32, a power semiconductor module with a switching device 2 is arranged, the switching device having a base plate 200 forming the plate element 20. On this base plate 200, a conventional power electronic substrate with power semiconductor components is arranged (not shown). Other necessary components of the power semiconductor module or the switching device, such as power connection elements, are also not shown here for the sake of clarity.

[0026] Particularly in especially compact designs of the power electronic system 1, the plate element 20 projects laterally beyond the second subbody 32 or its subsurface 320 in at least one, preferably two opposite or even all directions.

[0027] Fig. Figure 2 shows a section through a second embodiment of a power electronic system 1 according to the invention. The first partial body 30 again has an inlet and outlet volume region 34, 38 and a partial surface 302. In addition, the second partial body 32 has a centrally arranged dome 31. The dome 31 is cylindrical and has a blind hole 316 with an internal thread, which is accessible from the partial surface 320 of the second partial body.

[0028] Also unlike the first embodiment, some of the heat transfer bodies 5 not only extend into the cooling volume area 36, ​​but up to its bottom surface 360 ​​and there form a support against the deflection of the second sub-body 32.

[0029] The switching device 2 is also designed in a conventional manner; however, the plate element 20 is formed by the power electronic substrate 202 of the switching device 2. This substrate also has a central recess 216 for a fastening device, in this case a screw connection device 24 corresponding to the recess 316 of the dome 31. Also shown are conductor tracks 220, power semiconductor components 222, and an internal connection device 224 of the switching device 2.

[0030] Fig. Figure 3 shows a view of the heat transfer elements 5 of the second sub-body 30 of the liquid cooling device 3 of this second embodiment. The individual heat transfer elements are arranged in rows, these rows being offset from each other by half the distance between two heat transfer elements, resulting in a matrix-like arrangement with a homogeneous, i.e., equidistant, distribution of the individual heat transfer elements. The majority of these heat transfer elements 5, more precisely all those not arranged on a longitudinal side, have a rhomboid cross-section with rounded first and second corners 50, 52 and indented side surfaces 54; see also Figure 3. Fig. 4, up.

[0031] Fig. Figure 4 shows details of the heat transfer bodies 5 with diamond-shaped, dashed lines, cross-sections. These have a long diagonal 502 extending between the two first rounded corners 50 and a short diagonal 522 extending between the two second rounded corners 52.

[0032] Furthermore, the corner radii of the first corners 50 and the corner radii of the second corners 52, as well as the indentation radius 540 of the lateral indentations, are shown.

[0033] Fig. Figure 5 shows further details of these heat transfer bodies 5. A heat transfer body 5 is shown, as well as its nearest and next-but-one neighbor, assuming a homogeneous distribution of the relevant heat conducting bodies. In particular, the shortest first distance 560 to a nearest neighbor and the shortest second distance 562 to a next-but-one neighbor are shown.

[0034] Fig. Figure 6 shows a three-dimensional view of the second sub-body 32 with the dome 31 of a liquid cooling device 3 of a third embodiment of a power electronic system 1 according to the invention, and additionally an enlarged view of a heat conductor 5. This heat conductor 5 has a base section 510 and a main section 512. The base section 510 serves here for the connection to the plate-shaped base body, cf. Fig. 1. The main section 512 has a constant cross-section over its entire length, with this main section 512 forming the basis of all the above size ratios.

[0035] The arrangement of the heat conductors, their basic design and the advantageous dimensioning of the size ratios result in excellent heat transfer from the second sub-body to a cooling fluid flowing through the spaces between the heat conductors.

[0036] Fig. Figure 7 shows a three-dimensional view of a section through this third embodiment of this liquid cooling device 3. This liquid cooling device 3 in turn has a first subbody 30, which in this embodiment has a plurality of similar recesses, cf. Fig. 1, in each of which a second subbody 32 is arranged. Thus, a plurality of cooling volume regions 36 are formed, wherein an inlet volume region 34 and the outlet volume region 38 each have a plurality of branches so that the cooling volume regions 36 can be supplied with a liquid cooling medium in parallel.

[0037] The dome 31 extending from the respective second sub-body 32 is not only in mechanical contact with the first sub-body 30, but extends section by section into it and is also materially connected to it there.

Claims

[1] Power electronic system (1) with a switching device (2) and with a liquid cooling device (3), wherein the switching device (2) has a plate element (20) on the side of which facing away from the liquid cooling device (3) power semiconductor components (222) are arranged on electrically insulated conductor tracks (220) and are connected in a circuit-appropriate manner by means of a connecting device (224), wherein the liquid cooling device (3) has a first subbody (30) with an inlet volume region (34) and an outlet volume region (38) and a second subbody (32), wherein a cooling volume region (36) is formed between the two subbodies, wherein heat transfer elements (5) project from the second subbody (32) into the cooling volume region (36), wherein the second subbody (32) is arranged in a recess (306) of the first subbody (30) and the two subbodies (30, 32) are connected to each other in a materially bonded and liquid-pressure-tight manner and have a common planar first surface (300) which forms a first main surface and wherein the majority of the heat transfer bodies (5) have a rhomboid cross-section with rounded first and second corners (50, 52), wherein a long diagonal (502) extends between the two first rounded corners (50) and a short diagonal (522) extends between the two second rounded corners (52), and indented side surfaces (54), wherein the ratio of a corner radius (500) of the first corner (50) to a corner radius (520) of the second corner (52) is between 1 : 1 and 1 :

2. [2] Power electronic system according to claim 1, wherein the plate element (20) of the switching device (2) is arranged, preferably force-fit, on the first surface (300). [3] Power electronic system according to one of the preceding claims, wherein one or all heat transfer bodies (5) are in mechanical contact with a floor area (360) of the cooling volume area (36). [4] Power electronic system according to one of the preceding claims, wherein the heat transfer body (5) has a foot section (510) and a main section (512) and this main section (512) preferably has a constant cross-section over its entire length. [5] Power electronic system according to one of the preceding claims, wherein the ratio of the short diagonal (522) of one of the heat transfer bodies (5) to the long diagonal (502) of this heat transfer body (5) is between 1 : 1.1 and 1 : 1.6, preferably between 1 : 1.2 and 1 : 1.

4. [6] Power electronic system according to one of the preceding claims, wherein the ratio of the corner radius (500) of the first corner (50) to the corner radius (520) of the second corner (52) is between 1 : 1.2 and 1 : 1.

6. [7] Power electronic system according to one of the preceding claims, wherein the ratio of the corner radius (520) of the second corner (52) to a retraction radius (540) of the retraction of one of the side surfaces (54) is between 1 : 1 and 1 : 2, preferably between 1 : 1.2 and 1 : 1.

6. [8] Power electronic system according to one of the preceding claims, wherein the ratio of a shortest first distance (560) of the heat transfer body (5) to a nearest neighbor to a shortest second distance (562) of the heat transfer body (5) to a neighbor beyond next is between 1 : 1.2 and 1 : 2, preferably between 1 : 1.4 and 1 : 1.6.

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