Power electronic system with switching device and liquid cooling device

Abstract

This invention relates to a power electronic system having a switching device and a liquid cooling device, wherein the switching device has a board element on which a power semiconductor component is arranged on the side of the board element opposite to the liquid cooling device, wherein the liquid cooling device has a first part and a second part, the first part having an inflow volume region and an outflow volume region, wherein a cooling volume region is constructed between the two parts, wherein a plurality of heat transfer elements extend from the second part into the cooling volume region, wherein the second part is preferably completely disposed in a recess of the first part, and the two parts are connected to each other by means of material locking and liquid pressure sealing and have a common flat surface constituting a first main surface, wherein the liquid cooling device is constructed and configured for coolant to flow from the inflow volume region through the cooling volume region to the outflow volume region, and wherein the board element of the switching device is force-lockedly disposed on the first surface.

Description

Technical Field

[0001] The present invention describes a power electronic system having a liquid cooling device and a switching device, wherein the power electronic system is preferably configured as a power semiconductor module. Background Technology

[0002] A liquid-cooled circuit device is known from the prior art, for example, as disclosed in US 6,594,149 B2. This circuit device includes: a switching module having switching circuit elements and a switching module substrate, the switching circuit elements being disposed on the switching module substrate; a switching housing for housing the switching module; and a coolant chamber for guiding coolant in contact with the rear side of the module substrate of the switching module.

[0003] A common drawback of such systems is insufficient cooling capacity, where typical heat generated by losses in the switching devices must be dissipated to the cooling medium in order to protect the switching devices from overheating and thus damage. Summary of the Invention

[0004] In light of these facts, the objective of this invention is to improve the liquid cooling device for power electronic systems, thereby improving heat transfer from the switching devices of the power electronic systems to the cooling medium, or more precisely, the coolant.

[0005] According to the present invention, this task is accomplished by a power electronic system having a switching device and a liquid cooling device, wherein the switching device has a board element on which power semiconductor structural elements are arranged on electrically insulated conductor traces on the side of the board element away from the liquid cooling device, and the power semiconductor components are connected in a manner conforming to circuit design by means of a connecting device, wherein the liquid cooling device has a first part and a second part, the first part having an inflow volume region and an outflow volume region, wherein a cooling volume region is constructed between the two parts, wherein a plurality of heat transfer elements extend into the cooling volume region from the second part, wherein the second part is preferably completely arranged in a recess of the first part, and the two parts are connected to each other by means of material locking and liquid pressure sealing and have a common flat surface constituting a first main surface, wherein the liquid cooling device is constructed and arranged for coolant to flow from the inflow volume region through the cooling volume region to the outflow volume region, and wherein the board element of the switching device is force-lockedly arranged on the first surface.

[0006] It may be advantageous for the board element to be configured as a substrate or a base for a power electronic device. The substrate and the base for the power electronic device, or only the base for the power electronic device, are advantageously part of a power semiconductor module.

[0007] Preferably, the plate element is arranged entirely on the partial surface of the first surface composed of the second segment, or wherein the plate element overlaps with the partial surface of the second segment on at least one side and also rests against the partial surface of the first segment.

[0008] Preferably, the heat transfer body has a circular, elliptical, polyhedral, or freely shaped base surface and is constructed in a pointed, tapered, or non-tapered manner. Preferably, at least one heat transfer body, more preferably multiple heat transfer bodies, and again preferably not all of the heat transfer bodies are in mechanical contact with the bottom surface of the cooling volume region.

[0009] It is particularly advantageous that the first component is made of a first material and the second component is made of a second material different from the first material. Both components may also be made of aluminum or an aluminum alloy. It is also preferred that the second thermal conductivity of the second material is at least 10%, preferably at least 25%, higher than the first thermal conductivity of the first material, and wherein the second thermal conductivity is preferably at least 230 W / (mK).

[0010] Preferably, the first part has an arch seat with a top surface that is flush with a common surface, and the arch seat extends through a recess in the second part and preferably has a blind hole with internal threads.

[0011] Furthermore, it is advantageous that the first segment has multiple recesses of the same type, within which second segments of the same type are arranged, thus constructing multiple cooling volume regions, wherein the inflow volume region and the outflow volume region each have multiple branches, thereby allowing the cooling volume regions to flow through in parallel. Here, the second segments are constructed in a cuboid shape and arranged in adjacent rows along the longitudinal side of the second segments. This allows the assigned cooling volume regions to be traversed by the cooling medium in the longitudinal direction.

[0012] Furthermore, it is advantageous that the inflow volume region has a cross-sectional variation, wherein each branch of the inflow volume region is traversed by the same amount of liquid per unit time. Particularly advantageous is that the outflow volume region thus has a cross-sectional variation associated with the inflow volume region.

[0013] Preferably, the first segment has an additional recess extending from the second main surface, and a second segment is arranged in the additional recess in a material-locked and liquid-pressure-sealed manner. The surface of the second segment and the second main surface form another common flat surface. The cooling volume region of the second segment is also constructed and configured such that water flows from the inflow volume region through the cooling volume region to the outflow volume region. Here, the first and second main surfaces are arranged parallel to each other and back-to-back.

[0014] It should be understood that various design schemes of the present invention can be implemented individually or in any combination to achieve improvements. In particular, the features mentioned above and explained herein or below can be used not only in the specified combinations, but also in other non-exclusive combinations or individually, without departing from the scope of the present invention. Attached Figure Description

[0015] Further explanation, advantageous details and features of the invention will be provided below. Figures 1 to 8 As can be seen from the description of the embodiments of the invention or parts thereof, which are schematically illustrated in the diagram.

[0016] Figure 1 A cross-section is shown through a first design of the power electronic system according to the invention;

[0017] Figure 2 A cross-section is shown through a second design scheme of the power electronic system according to the invention;

[0018] Figure 3 An observation of the liquid cooling device for this second design is shown;

[0019] Figure 4 A three-dimensional view of the power semiconductor module with switching device of the second design is shown;

[0020] Figure 5 A three-dimensional view of a first design of a liquid cooling device for a power electronic system according to the present invention is shown;

[0021] Figure 6 and Figure 7 A three-dimensional view of a second design of a liquid cooling device for a power electronic system according to the present invention is shown;

[0022] Figure 8 A three-dimensional view of a third design of a liquid cooling device for a power electronic system according to the present invention is shown. Detailed Implementation

[0023] Figure 1 A cross-section of a first design of the power electronic system 1 according to the present invention is shown, illustrating a liquid cooling device 3 having first and second sections 30, 32. The first section 30 has an inflow volume region 34 and an outflow volume region 38, which extend into the plane of the drawing and respectively form channels therein. A cooling volume region 36 is constructed between the inflow and outflow volume regions 34, 38.

[0024] To form the cooling volume region 36, the first segment 30 has a recess 306, in which the second segment 32 is disposed. The second segment 32 has a plate-like basic shape and a heat transfer element 322 extending from it and into the cooling volume region 36. The plate-like basic shape has a flat partial surface 320 on the side facing away from the cooling volume region 36. This flat partial surface 320 and the flat partial surface 320 surrounding the first segment 30 form a common flat first surface 300 of the liquid cooling device 3.

[0025] In this embodiment, the plate-like basic shape of the second component 32 rests around the resting surface of the first component 30. A connecting mechanism 4, in this case, is brazing solder 40 (see [link to relevant documentation]). Figure 2 Thus, the second component 32 is arranged in the recess 306 in a material-locked and liquid-pressure-sealed manner, and the cooling volume region 36 is configured such that coolant can flow through the cooling volume region 34 to the outflow volume region 38. The solder 40 protrudes beyond the first surface 300. However, the solder can also retract relative to the first surface, thus forming a groove. Particularly preferred is that the solder 40 protrudes after arrangement and is ground flush with the first surface 300 in a further manufacturing step.

[0026] As an alternative to brazing the joint 40, the material-locking joint between the first and second parts 30, 32 can also be constructed as a welded joint. In the case of the preferred laser welding joint, no specific connection mechanism is arranged.

[0027] The two aforementioned designs for material-locking connections are particularly preferred when the first component 30 is made of aluminum or an aluminum alloy with a first thermal conductivity and the second component 32 is made of aluminum or an aluminum alloy with a higher second thermal conductivity. The main advantage of this design is that the material of the first component 30 can be optimized in terms of its mechanical stability, while the material of the second component 32 can be optimized in terms of its heat transfer characteristics. Therefore, the resulting hybrid liquid cooling device has significant advantages in terms of its overall physical properties compared to conventional liquid cooling devices made of only one material.

[0028] A power semiconductor module having a switching device 2 is arranged on a portion 320 of the second component 32. The switching device has a substrate 200 constituting the board element 20. Although not shown, a substrate for a power electronic device having power semiconductor components, conventional in the art, is arranged on this substrate 200. For clarity, other necessary components of the power semiconductor module or the switching device, such as current connection elements, are also not shown here.

[0029] Especially in the particularly compact design of the power electronic system 1, the board element 20 extends laterally beyond the second split 32 or a portion of the second split surface 320 in at least one direction, preferably two opposite directions, or even all directions.

[0030] Figure 2 A cross-section through a second design of the power electronics system 1 according to the invention is shown. The first segment 30 here further has inflow and outflow volume regions 34 and 38, and a partial surface 302. Furthermore, the first segment 30 has an arch 31 centrally arranged in a recess 306, the arch having a top surface 310. This top surface 310 is constructed and arranged to be flush with the partial surface 302 of the first segment 30 and with a common surface. The arch 31 is cylindrically constructed and has a blind hole 316 with internal threads.

[0031] The second part 32 differs from the second part according to the first design in that it has a recess 324 corresponding to the arch 31 (see...). Figure 3 The arch 31 passes through the recess. Of course, a material-locking and liquid-pressure-sealed connection 4 is also constructed between the arch 31 and the second part 32, which is again exemplarily constructed by means of brazing 42.

[0032] Unlike the first design, some of the heat transfer elements 322 not only extend into the cooling volume region 36, but also extend to its bottom surface 360, where they respectively form supports to resist the deflection of the second component 32.

[0033] The switching device 2 is constructed in the same manner as is customary in the art; however, the board element 20 is formed by the substrate 202 of the power electronics of the switching device 2. The switching device also has a central recess 216 for the fastening device (here, a screw-in device 24 corresponding to the recess of the arch). Furthermore, the conductor traces 220, power semiconductor components 222, and internal connection devices 224 of the switching device 2 are also shown.

[0034] Figure 3 An observation of the liquid cooling device 3 of this second design is shown. A portion of the surface 302 of the first component 30 and its recess 306 for accommodating the second component 32 are shown. A portion of the surface 320 of the second component 32 and its recess 324 for the arch 31 of the first component 30 are also shown. The material-locking connection between the two components is constructed as described above. Furthermore, the positions of the heat transfer elements 322, each constructed in a cylindrical shape, are also shown. These heat transfer elements are, of course, arranged within the cooling volume region.

[0035] Figure 4A three-dimensional view of the power semiconductor module with switching device 2 of the second design is shown. The power semiconductor module has the aforementioned switching device 2 on a substrate 202 with power electronics, the substrate having a central recess 216 for arranging screw connections. Electrical loads and auxiliary contact devices 280, 282, and 284, conventional in the art, are also shown.

[0036] Figure 5 A three-dimensional view of a first design of a liquid cooling device 3 for a power electronic system according to the present invention is shown. A first sub-body 30 is shown, having four identical recesses 306 for arranging second sub-body 32. The first sub-body 30 further has inflow and outflow volume regions 34, 38, which are configured as two parallel channels and enclosed by covers 342, 382 on the surface opposite to the first main surface. Branches 340, 380 extend from these channels (see also...). Figure 2 Branches 340 of the inflow volume region 34 are configured to guide the coolant into their respective cooling volume regions 36.

[0037] Advantageously, the cross-sections of the branches 340 are designed such that the same amount of liquid flows through each cooling volume region 36 per unit time. The branches 380 of the outflow volume region 38 are constructed similarly. Alternatively or additionally, the cross-sectional variations can be configured according to the inflow and outflow volume regions 34, 38.

[0038] The second part 32 is basically in accordance with Figure 1 The configuration is as described, wherein the second components, more precisely, their plate-like basic shape, are constructed in a cuboid form. The recesses 306 of the first component 30, and subsequently the second components 32, are arranged adjacent to each other along their longitudinal sides. The first component 30 is constructed in a matching manner, such that the cooling volume regions 36 respectively belonging to the second components 32 are permeated in the longitudinal direction.

[0039] In terms of materials technology, the first and second components 30 and 32, as described above, are made of materials with different coefficients of thermal expansion. This also applies to the following embodiments.

[0040] Figure 6 and Figure 7 A three-dimensional view of a second design of the liquid cooling device 3 for a power electronic system according to the present invention is shown. Figure 6 The liquid cooling device 3 shows a continuous flat surface through which the first and (here, six) second subdivisions 30, 32 are formed by partial surfaces 302, 320. Figure 7 An additional liquid coupling element for connection to a liquid cooling system is shown.

[0041] Figure 8A three-dimensional view of a third design of the liquid cooling device 3 for a power electronic system according to the invention is shown. The first component 30, constructed in multiple parts, has additional recesses 306 extending from a second main surface parallel to the first main surface. Further second components 32 are arranged in these additional recesses in a material-locked and liquid pressure-sealed manner. The liquid cooling device 3 is thus configured to allow switching devices to be arranged on both main sides. The power electronic system constructed in this way thus has a particularly high power density while having a smaller external size.

Claims

1. A power electronic system (1), the power electronic system having a switching device (2) and a liquid cooling device (3). in, The switching device (2) has a plate element (20) on the side of the plate element facing away from the liquid cooling device (3), on electrically insulated conductor traces, and the power semiconductor structural elements are connected in a manner consistent with circuit design by means of a connecting device. The liquid cooling device (3) has a first section (30) and a second section (32). The first section has an inflow volume region (34) and an outflow volume region (38). A cooling volume region (36) is constructed between the two sections. Multiple heat transfer elements (322) extend from the second section (32) into the cooling volume region (36). The second component (32) is disposed in the recess (306) of the first component (30), and the two components (30, 32) are connected to each other by means of material locking and liquid pressure sealing and have a common flat surface constituting the first surface (300). The liquid cooling device (3) is constructed and configured to allow coolant to flow from the inflow volume region (34) through the cooling volume region (36) to the outflow volume region (38). The plate element (20) of the switching device (2) is force-lockedly arranged on the first surface (300). Furthermore, the first segment (30) has multiple recesses (306) of the same type, in which second segments (32) of the same type are arranged, thus constructing multiple cooling volume regions (36), wherein the inflow volume region (34) and the outflow volume region (38) each have multiple branches (340, 380), thereby enabling the cooling volume regions (36) to be flowed through in parallel.

2. The power electronic system according to claim 1, wherein, The board element (20) is configured as a substrate (200) or a base (202) for a power electronic device.

3. The power electronic system according to claim 1 or 2, wherein, The plate element (20) is arranged entirely on the portion (320) of the first surface (300) formed by the second component (32), or The plate element (20) overlaps with a portion of the second split (32) on at least one side and also rests on a portion of the first split (30) on a portion of the first split (30).

4. The power electronic system according to claim 1 or 2, wherein, The heat transfer element (322) has a circular, elliptical, polyhedral or free-form base surface and is constructed to be pointed, tapered or non-tapered.

5. The power electronic system according to claim 4, wherein, At least one of the heat transfer elements (322) is in mechanical contact with the bottom surface (360) of the cooling volume region (36).

6. The power electronic system according to claim 4, wherein, Multiple heat transfer elements are in mechanical contact with the bottom surface (360) of the cooling volume region (36).

7. The power electronic system according to claim 6, wherein, Not all of the heat transfer element is in mechanical contact with the bottom surface (360) of the cooling volume region (36).

8. The power electronic system according to claim 1 or 2, wherein, The first component (30) is made of a first material and the second component (32) is made of a second material different from the first material.

9. The power electronic system according to claim 5, wherein, The two parts (30, 32) are made of aluminum or aluminum alloy.

10. The power electronic system according to claim 8, wherein, The second thermal conductivity of the second material is at least 10% higher than the first thermal conductivity of the first material.

11. The power electronic system according to claim 8, wherein, The second thermal conductivity of the second material is at least 25% higher than the first thermal conductivity of the first material.

12. The power electronic system according to claim 10, wherein, The second thermal conductivity is at least 230 W / (mK).

13. The power electronic system according to claim 1 or 2, wherein, The first segment (30) has an arch (31) with an arch top surface (310) that is flush with a common surface and the arch (31) extends through a recess (324) of the second segment (32).

14. The power electronic system according to claim 13, wherein, The arch (31) has a blind hole (316) with internal threads.

15. The power electronic system according to claim 1 or 2, wherein, The second segment (32) is constructed in a cuboid shape and is arranged in adjacent rows along the longitudinal side of the second segment, thereby allowing the associated cooling volume area (36) to be traversed in the longitudinal direction.

16. The power electronic system according to claim 1 or 2, wherein, The inflow volume region (34) has a cross-sectional variation, wherein each branch (340) of the inflow volume region (34) is flowed by the same amount of liquid per unit time.

17. The power electronic system according to claim 16, wherein, The outflow volume region (38) has a cross-sectional variation associated with the inflow volume region (34).

18. The power electronic system according to claim 1 or 2, wherein, The first part (30) has an additional recess extending from the second main surface, in which another second part (32) is arranged in a material-locked and liquid pressure-sealed manner, and wherein the surface of the other second part forms another common flat surface with the second main side, and wherein the cooling volume region of the other second part is also constructed and arranged such that it flows from the inflow volume region (34) through the cooling volume region (36) to the outflow volume region (38).

19. The power electronic system according to claim 18, wherein, The first and second main faces are arranged parallel to each other and facing away from each other.

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