Power electronic system comprising switching device and liquid cooling device

Abstract

The invention relates to a power electronics system comprising a switching device having a plate element and a liquid cooling device, on a side of the plate element facing away from the liquid cooling device, power semiconductor components are arranged on conductor tracks that are electrically insulated from one another, the power semiconductor components are connected in a circuit-compatible manner by means of a connecting device, and the liquid cooling device has a first part and a second part with an inlet volume region and an outlet volume region, a cooling volume region being formed between the two parts, the heat transfer bodies protrude from a second partial body into the cooling volume region, the second partial body being arranged in a recess in the first partial body, and the two partial bodies being connected to each other in a bonded and liquid pressure-tight manner and having a common flat surface forming a first main surface, the plurality of heat transfer bodies having a rhombic cross-section, the housing has a rounded first corner and a rounded second corner and a recessed side surface.

Description

Technical Field

[0001] The present invention describes a power electronic system comprising a liquid cooling device and a switching device, wherein the switching device is preferably in the form of a power semiconductor module. Background Art

[0002] A liquid-cooled switching device is known from the prior art, for example, as disclosed in US 6,594,149 B2. It includes a switching module, a switching housing, and a cooling liquid chamber. The switching module has circuit elements and a switching module substrate on which the circuit elements are mounted. The switching housing is for holding the switching module, and the cooling liquid chamber is for guiding the cooling liquid into contact with the rear side of the module substrate of the switching module.

[0003] DE 1 020201 32689 A1 discloses a power electronic system comprising a switching device and a liquid cooling device. The switching device has a plate element on the side facing away from the liquid cooling device, on which power semiconductor components are arranged on mutually electrically insulated conductor tracks and are connected to each other in a circuit-compatible manner by means of connecting means. The liquid cooling device has a first partial body with an inlet volume region and an outlet volume region and has a second partial body, wherein a cooling volume region is formed between the two partial bodies, and a plurality of heat transfer bodies project from the second partial body into the cooling volume region. The second partial body is preferably completely arranged in a recess in the first partial body, and the two partial bodies are connected to each other in a materially bonded and liquid-pressure-sealed manner and have a common flat surface forming a first main surface. The liquid cooling device is designed and arranged such that the cooling liquid flows from the inlet volume region via the cooling volume region to the outlet volume region, and wherein the plate element of the switching device is arranged on the first surface in a press-fit manner.

[0004] Such systems always have the disadvantage of insufficient cooling capacity, where the energy (usually thermal energy) typically caused by losses in the switching device has to be dissipated into the cooling medium in order to protect the switching device from overheating and thus from destruction. Summary of the Invention

[0005] In view of these mentioned circumstances, the present invention is based on the following object: to develop a liquid cooling device for a power electronic system such that the heat transfer from the switching device of the power electronic system to the cooling medium (more precisely to the cooling liquid) is improved.

[0006] According to the present invention, this object is achieved by a power electronics system, which includes a switching device and a liquid cooling device. The switching device has a board element, and power semiconductor components are arranged on a side of the board element facing away from the liquid cooling device, on mutually electrically insulated conductor tracks, and these power semiconductor components are connected in a circuit-compatible manner by means of connecting devices. The liquid cooling device has a first partial body and a second partial body. The first partial body has an inlet volume region and an outlet volume region. A cooling volume region is formed between the two partial bodies. A heat transfer body protrudes from the second partial body into the cooling volume region. The second partial body is arranged in a recess in the first partial body, and the two partial bodies are connected to each other in a materially bonded and liquid-tight manner and have a common flat surface, which forms a first main surface. And the plurality of heat transfer bodies have a rhombic cross-section, which has a circular first corner and a circular second corner and a recessed side surface.

[0007] Particularly preferably, the board element of the switching device is preferably arranged on the first surface in a press-fit manner.

[0008] It may be advantageous if individual or all of the heat transfer bodies are in mechanical contact with the base surface of the cooling volume region.

[0009] Preferably, the second partial body has a dome, and the dome extends in the direction of the first partial body and preferably has a blind hole with an internal thread. Here, preferably, the dome is in mechanical contact with the base surface of the cooling volume region or is connected to the base surface in a materially bonded manner. In addition, preferably, the dome extends into the base surface.

[0010] Furthermore, it may be preferable if the heat transfer body has a bottom section and a main section, and the main section preferably has a constant cross-section over its entire length. Insofar as there is a bottom section, the following dimensional relationships relate to the main section of the heat transfer body.

[0011] It may be advantageous if the ratio of the short diagonal to the long diagonal of one of the heat transfer bodies is between 1:1.1 and 1:1.6, preferably between 1:1.2 and 1:1.4.

[0012] It may also be advantageous if the ratio of the corner radius of the first corner to the corner radius of the second corner is between 1:1 and 1:2, preferably between 1:1.2 and 1:1.6.

[0013] Furthermore, it may be advantageous that the ratio of the corner radius of the second corner to the recess radius of the recessed portion of one of the side surfaces is between 1:1 and 1:2, preferably between 1:1.2 and 1:1.6.

[0014] It may be preferred that the ratio of the first shortest distance of the heat transfer body portion to the nearest adjacent heat transfer body portion to the second shortest distance of the heat transfer body portion to the next adjacent heat transfer body portion is between 1:1.2 and 1:2, preferably between 1:1.4 and 1:1.6.

[0015] It goes without saying that the different improvements of the present invention can be implemented individually or in any desired combination to achieve improvement. In particular, without departing from the scope of the present invention, the features mentioned above and explained herein or hereinafter can be used not only in the specified combinations, but also in other combinations that are not mutually exclusive, or they can be used alone. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Further explanations, advantageous details and features of the present invention can be inferred from the following description of the exemplary embodiments of the present invention or their corresponding parts schematically shown in Figures 1 to 7 Inferable from the following description of the exemplary embodiments of the present invention or their corresponding parts schematically shown in

[0017] Figure 1 Showing a cross-section through a first improvement of a power electronics system according to the present invention.

[0018] Figure 2 Showing a cross-section through a second improvement of a power electronics system according to the present invention.

[0019] Figure 3 Showing a view of the heat transfer body portion of the second partial body of the liquid cooling device of this second improvement.

[0020] Figure 4 Showing details of these heat transfer body portions.

[0021] Figure 5 Showing further details of these heat transfer body portions.

[0022] Figure 6 Showing a three-dimensional view of the second partial body of the liquid cooling device of a third improvement of a power electronics system according to the present invention.

[0023] Figure 7 Showing a three-dimensional view of a cross-section through this third improvement of the liquid cooling device. DETAILED DESCRIPTION OF THE INVENTION

[0024] Figure 1Shows a cross-section of a first improvement of the power electronic system 1 according to the present invention. The figure shows a liquid cooling device 3 having a first partial body 30 and a second partial body 32. The first partial body 30 has an inlet volume region 34 and an outlet volume region 38, each of these volume regions extending into the plane of the drawing and each forming a channel therein. A cooling volume region 36 is formed between the inlet volume region 34 and the outlet volume region 38.

[0025] To form this cooling volume region 36, the first partial body 30 has a recess 306, and the second partial body 32 is arranged in the recess 306. The second partial body 32 has a plate-like basic shape or body, and a heat transfer body portion 5 extending from the plate-like basic shape or body and protruding into the cooling volume region 36. The plate-like basic shape forms a flat local surface 320 on the side thereof remote from the cooling volume region 36. This flat local surface 320 and the surrounding flat partial surface 302 of the first partial body 30 together form a common flat first surface 300 of the liquid cooling device 3.

[0026] In this embodiment, the plate-like basic shape of the second partial body 32 rests circumferentially on the support surface of the first partial body 30. A connecting device 4, here a hard solder 40 (see Figure 2 ) is arranged between the edge region of the second partial body 32 and the corresponding inner edge of the first partial body 30. Thus, the second partial body 32 is arranged in the recess 306 in a materially bonded and liquid-pressure-sealed manner, and the cooling volume region 36 is formed in such a way that cooling liquid can flow through it from the inlet volume region 34 to the outlet volume region 38. Here, the hard solder 40 protrudes beyond the first surface 300. However, it can also be recessed relative to this surface and thus form a groove. Particularly preferably, the hard solder 40 protrudes after being arranged and is ground flush with the first surface 300 in a further production step.

[0027] As an alternative to the hard solder connection 40, the materially bonded connection between the first partial body 30 and the second partial body 32 can also be in the form of a welding connection. In the case of a preferred laser welding connection, no explicit connecting device is arranged.

[0028] A power semiconductor module including a switching device 2 is arranged on the local surface 320 of the second partial body 32. The switching device 2 has a substrate 200 forming a plate element 20. A conventional power electronic substrate with power semiconductor components is arranged on this substrate 200, but not shown. For the sake of clarity, other necessary elements of the power semiconductor module or the switching device, such as power connection elements, are likewise not shown here.

[0029] In particular, in the case of a particularly compact improvement of the power electronic system 1, the plate element 20 projects laterally beyond the second partial body 32 or its partial surface 320 in at least one direction, preferably in two opposite directions or even in all directions.

[0030] Figure 2 Fig. shows a cross-section of a second improvement of the power electronic system 1 according to the invention. Here, the first partial body 30 again has an inlet volume region 34, an outlet volume region 38 and a partial surface 302 respectively. 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.

[0031] Similarly, compared with the first improvement, some of the heat transfer bodies 5 not only extend into the cooling volume region 36, but also extend as far as the base surface 360 of the cooling volume region, and there respectively form supports for preventing the second partial body 32 from sagging.

[0032] The switching device 2 also has a conventional design here, but the plate element 20 is formed by the power electronic substrate 202 of the switching device 2. The switching device also has a central recess 216 for the fastening device, here the fastening device is a screw connection device 24, corresponding to the recess 316 in the dome 31. Also shown are the conductor tracks 220, the power semiconductor components 222 and the internal connection devices 224 of the switching device 2.

[0033] Figure 3 Fig. shows a view of the heat transfer bodies 5 of the second partial body 30 of the liquid cooling device 3 of this second improvement. The individual heat transfer bodies are arranged in rows, and these rows are arranged offset from each other by half the distance between two heat transfer bodies, such that a matrix-like arrangement with a uniform (i.e., equidistant) distribution of the individual heat transfer bodies relative to each other is produced. A plurality of said heat transfer bodies 5 (more precisely, all heat transfer bodies not arranged on the longitudinal sides) have a rhombic cross-section, which has a circular first corner 50, a circular second corner 52 and a recessed side surface 54. In this regard, also see Figure 4 .

[0034] Figure 4 Fig. shows a detail of the heat transfer body 5 with a rhombic cross-section, shown in dashed lines. These heat transfer bodies have a long diagonal 502 extending between two circular first corners 50 and a short diagonal 522 extending between two circular second corners 52.

[0035] In addition, the corner radius of the first corner 50, the corner radius of the second corner 52, and the recess radius 540 of the laterally recessed portion are shown.

[0036] Figure 5 Shows further details of these heat transfer body parts 5. The figure shows a heat transfer body part 5, and its corresponding next and next adjacent heat transfer body parts, where it is assumed here that the relevant heat transfer body parts are evenly distributed. The figure particularly shows the first shortest distance 560 to the next adjacent heat transfer body part and the second shortest distance 562 to the next adjacent heat transfer body part.

[0037] Figure 6 An enlarged view showing a three-dimensional view of a second partial body part 32 having a dome 31 and additional heat transfer body parts 5 of the third improved liquid cooling device 3 of the power electronic system 1 according to the present invention. The heat transfer body part 5 has a bottom section 510 and a main section 512. Here, the bottom section 510 is used for connection to the plate-like body, see Figure 1 . The main section 512 has a constant cross-section over its entire length. Wherein the main section 512 forms the basis for any of the above ratios.

[0038] The arrangement of the heat transfer body parts, their basic structure and the advantageous ratio sizes result in excellent heat transfer of the cooling liquid from the second partial body part to the intermediate space through which the cooling liquid flows between the heat transfer body parts.

[0039] Figure 7 Shows a three-dimensional view of a cross-section of the third improvement of the liquid cooling device 3. The liquid cooling device 3 also has a first partial body part 30, which has a plurality of identical recesses in this improvement, see Figure 1 , and a second partial body part 32 is arranged in each of these recesses. Thus, a plurality of cooling volume regions 36 are formed, where the inlet volume region 34 and the outlet volume region 38 each have a plurality of branches, such that the liquid cooling medium can flow through the cooling volume regions 36 in parallel.

[0040] The dome 31 starting from the corresponding second partial body part 32 not only makes mechanical contact with the first partial body part 30, but also extends into the first partial body part in a partitioned manner and is also connected to the partial body part in a material-bonded manner there.

Claims

1. A power electronics system (1) comprising a switching device (2) and a liquid cooling device (3), wherein the switching device (2) has a plate element (20), on the side of the plate element facing away from the liquid cooling device (3), power semiconductor components (222) are arranged on mutually electrically insulated conductor tracks (220), and the power semiconductor components are connected in a circuit-compatible manner by means of a connecting device (224), The liquid cooling device (3) comprises a first partial body (30) and a second partial body (32), the first partial body (30) having an inlet volume region (34) and an outlet volume region (38), wherein a cooling volume region (36) is formed between the two partial bodies, wherein the heat transfer body (5) protrudes from the second partial body (32) into the cooling volume region (36), The second partial body (32) is arranged in a recess (306) in the first partial body (30), and the two partial bodies (30, 32) are connected to each other in a materially bonded and liquid pressure-tight manner and have a common flat surface forming a first surface (300), and The plurality of heat transfer bodies (5) have a rhombus-shaped cross section with a rounded first corner (50) and a rounded second corner (52) and a concave side surface (54).

2. The power electronic system according to claim 1, characterized in that: The plate element (20) of the switch device (2) is arranged on a first surface (300).

3. The power electronic system according to claim 1 or 2, characterized in that: Some or all of the heat transfer bodies (5) are in mechanical contact with a base surface (360) of the cooling volume (36).

4. The power electronic system according to claim 1 or 2, characterized in that: The second body part (32) has a dome (31), and the dome (31) extends in the direction of the first body part.

5. The power electronic system according to claim 4, characterized in that: The dome (31) is in mechanical contact with a base surface (360) of the cooling volume (36) or is connected to the base surface in a materially bonded manner.

6. The power electronic system according to claim 5, characterized in that: The dome (31) extends into the base surface (360).

7. The power electronic system according to claim 1 or 2, characterized in that: The heat transfer body (5) has a bottom section (510) and a main section (512).

8. The power electronic system according to claim 1 or 2, characterized in that: The ratio of the short diagonal (522) of one of the heat transfer bodies (5) to the long diagonal (502) of the heat transfer body (5) is between 1:1.1 and 1:1.

6.

9. The power electronic system according to claim 1 or 2, characterized in that: A 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.

10. The power electronic system according to claim 1 or 2, characterized in that: A ratio of a corner radius (520) of the second corner (52) to a concave radius (540) of the concave portion of one of the side surfaces (54) is between 1:1 and 1:

2.

11. The power electronic system according to claim 1 or 2, characterized in that: The ratio of a first shortest distance (560) between the heat transfer body (5) and the nearest adjacent heat transfer body to a second shortest distance (562) between the heat transfer body (5) and the next adjacent heat transfer body is between 1:1.2 and 1:

2.

12. The power electronic system according to claim 2, characterized in that: The plate element (20) of the switch device (2) is arranged on the first surface (300) in a press-fit manner.

13. The power electronic system according to claim 4, characterized in that: The dome (31) has a blind hole (316) with an internal thread.

14. The power electronic system according to claim 7, characterized in that: The main section (512) has a constant cross-section throughout its length.

15. The power electronic system according to claim 8, characterized in that: The ratio of the short diagonal (522) of one of the heat transfer bodies (5) to the long diagonal (502) of the heat transfer body (5) is between 1:1.2 and 1:1.

4.

16. The power electronic system according to claim 9, characterized in that: A ratio of a corner radius (500) of the first corner (50) to a corner radius (520) of the second corner (52) is between 1:1.2 and 1:1.

6.

17. The power electronic system according to claim 10, characterized in that: A ratio of a corner radius (520) of the second corner (52) to a concave radius (540) of a concave portion of one of the side surfaces (54) is between 1:1.2 and 1:1.

6.

18. The power electronic system according to claim 11, characterized in that: The ratio of a first shortest distance (560) between the heat transfer body (5) and the nearest adjacent heat transfer body to a second shortest distance (562) between the heat transfer body (5) and the next adjacent heat transfer body is between 1:1.4 and 1:1.6.

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