COOLING STRUCTURE OF A POWER CONVERSION DEVICE

Abstract

A cooling structure of a power conversion device comprises a semiconductor module containing a semiconductor element and having a heat dissipation surface on at least one surface, a heat dissipation element thermally connected to the heat dissipation surface of the semiconductor module and having a heat dissipation fin, a frame supporting the heat dissipation element, and a cover covering the heat dissipation element and the frame to form a water passage through the heat dissipation fin, wherein the frame has an opening into which the heat dissipation element is fitted in the direction of the frame, and a space between the fitted heat dissipation element and the opening is sealed by a sealing element, and the heat dissipation element is connected to the cover at a tip of the heat dissipation fin and is configuredto be displaceable by a pressure force exerted on the cover in the direction of the heat dissipation surface of the semiconductor module.

Description

Technical field

[0001] The present invention relates to a cooling structure of a power conversion device. State of the art

[0002] Power conversion devices, which convert direct current (DC) and alternating current (AC) power from a semiconductor element through a switching process, are widely used in electric vehicles, hybrid vehicles, and similar applications. The semiconductor element in the power conversion device generates heat during the switching process, necessitating a cooling structure with high heat dissipation capacity. In a semiconductor module containing a semiconductor element, a heat dissipation element, designed to cool the heat generated by the semiconductor element, is arranged to be thermally connected to a heat dissipation surface of the semiconductor module. This heat dissipation element features a heat dissipation fin, and a water passage through the heat dissipation fin serves as the cooling structure.

[0003] PTL 1 discloses a cooling device for a semiconductor module in which a tip surface of a first cooling pin rib and a tip surface of a second cooling pin rib are brought into contact with each other and displaced relatively according to an input load, wherein a first base, which is in contact with a side surface of the semiconductor module, is deformed with this displacement in order to reduce a gap between the semiconductor module and the first base.

[0004] PTL 2 also discloses a cold plate comprising a base plate with a plurality of parallel ribs and a cover that covers the plurality of ribs and defines an interior space between the cover and the base plate, wherein an uneven section is provided in a section of the interior space facing the upper surfaces of the plurality of ribs. List of literature on patent literature PTL 1: JP 2015-126117 A PTL 2: JP 2019-160832 A Summary of the invention: Technical problem

[0005] However, the heat dissipation performance of the power conversion device could not be improved in the devices described in PTL 1 and 2. Solution to the problem

[0006] A cooling structure of a power conversion device according to the present invention comprises a semiconductor module containing a semiconductor element and having a heat dissipation surface on at least one surface, a heat dissipation element thermally connected to the heat dissipation surface of the semiconductor module and having a heat dissipation fin, a frame supporting the heat dissipation element, and a cover covering the heat dissipation element and the frame to form a water passage through the heat dissipation fin, wherein the frame has an opening into which the heat dissipation element is fitted in the direction of the frame, and a space between the fitted heat dissipation element and the opening is closed by a sealing element, and the heat dissipation element is connected to the cover at a tip of the heat dissipation fin and is configuredto be displaceable by a pressure force exerted on the cover in the direction of the heat dissipation surface of the semiconductor module. Advantageous effects of the invention

[0007] According to the present invention, the heat dissipation performance of the power conversion device can be improved. Brief description of the drawings [ Fig. 1] Fig. Figure 1 is a perspective exploded view of a power conversion device. [ Fig. 2] Fig. Figure 2 is a cross-sectional view of the power conversion device. [ Fig. 3] Fig. 3(a) to Fig. 3(d) are cross-sectional diagrams illustrating an assembly process of the power conversion device. [ Fig. 4] Fig. Figure 4 is an enlarged cross-sectional view of a power conversion device according to a first modification. [ Fig. 5] Fig. Figure 5 is an enlarged cross-sectional view of a power conversion device according to a second modification. [ Fig. 6] Fig. Figure 6 is an enlarged cross-sectional view of a power conversion device according to a third modification. [ Fig. 7] Fig. Figure 7 is an enlarged cross-sectional view of a power conversion device according to a fourth modification. Description of the embodiments

[0008] Embodiments of the present invention are described below with reference to the drawings. The following description and drawings are to be understood as examples for describing the present invention and have been omitted and simplified to the extent necessary for clarity. Furthermore, the present invention can be implemented in various other forms. Unless otherwise limited, each component can also exist as one or more components.

[0009] The position, size, shape, area, and the like of each component shown in the drawings may not necessarily represent the actual position, size, shape, area, and the like, for the sake of clarity and to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, area, and the like disclosed in the drawings.

[0010] Fig. Figure 1 is a perspective exploded view of a power conversion device 1 according to an embodiment of the present invention.

[0011] The power conversion device 1 comprises a semiconductor module 2, a heat dissipation element 3, a frame 4, a cover 5, and the like. In the Fig. In the example shown, the power conversion device 1 also includes six (21 to 26) semiconductor modules 2 arranged in parallel.

[0012] The semiconductor module 2 is installed on a substrate 6. Other electronic components besides the semiconductor module 2, such as positioning holes, mounting points, and the like, are also installed on the substrate 6, but are located in Fig. 1 not shown.

[0013] The semiconductor module 2 further comprises a semiconductor element which is sealed with a sealing material and integrated within it. Both surfaces of the semiconductor module 2 are heat dissipation surfaces that dissipate heat generated by a switching process of the semiconductor element, and thermal conductivity elements 7 are located on both surfaces of the semiconductor module 2 (see Fig. 2), such as thermal grease and a thermally conductive film, installed.

[0014] The heat dissipation element 3 is thermally connected to the heat dissipation surface of the semiconductor module 2 and has a heat dissipation fin 8. Six heat dissipation elements 31 to 36, corresponding to the six semiconductor modules 21 to 26, are provided in the heat dissipation element 3. The frame 4 also has an opening 41 and supports the heat dissipation element 3 by fitting the heat dissipation element 3 into the opening 41. The opening 41 also contains six openings 41, which are to be fitted into the six heat dissipation elements 31 to 36. Furthermore, the cover 5 covers the heat dissipation element 3 and the frame 4 to form a water passage that runs through the heat dissipation fin 8. Details of the cover 5 will be described later with reference to Fig. 2 described.

[0015] However, it should be noted that the shape of the heat dissipation fin 8 is not limited to a particular shape, regardless of whether the heat dissipation fin 8 is a cylindrical pin fin or another shape.

[0016] Although in Fig. Although the underside of the substrate 6 is not shown in a perspective exploded view, the heat dissipation element 3, which has the heat dissipation fins 8, is thermally connected to the lower heat dissipation surface of the semiconductor module 2 in a similar manner to the top side. The heat dissipation element 3 is fitted into the opening 41 formed in the frame 4, and the cover 5, which covers the heat dissipation element 3 and the frame 4, is further designed to form a lower water passage that runs through the heat dissipation fin 8. The lower water passage and the upper water passage are also connected by a connecting section 10, with the cooling water circulated by a pump (not shown).

[0017] It should be noted, however, that the semiconductor module 2 can contain not only a single semiconductor element, but also a multitude of semiconductor elements. In this case as well, a heat dissipation surface is defined for the multitude of semiconductor elements, with a heat dissipation element 3 provided corresponding to the heat dissipation surface. Furthermore, the semiconductor module 2 can be divided into a multitude of parts. In this case too, a heat dissipation surface is defined for the multitude of semiconductor modules 2, with the heat dissipation element 3 provided corresponding to the heat dissipation surface.

[0018] Furthermore, an example is shown in the power conversion device 1 in which six (21 to 26) semiconductor modules 2 are arranged in parallel with respect to a cover 5, wherein the number of semiconductor modules 2 is arbitrary. In the present embodiment, an example is described in which the heat dissipation elements 3 are arranged on both surfaces of the semiconductor module 2, wherein the heat dissipation element 3 can also be arranged on only one surface of the semiconductor module 2. In this case, a housing and a fastening element are arranged on the other surface of the semiconductor module 2, wherein the other surface of the semiconductor module 2 is attached to the housing and the fastening element by a fastening element.

[0019] Fig. Figure 2 is a cross-sectional view of the power conversion device 1 in the present embodiment. This cross-sectional view is a cross-section along line AA' in Fig. 1 and illustrates a state in which the heat dissipation element 3, the frame 4, the cover 5 and the like are mounted on both surfaces of the semiconductor module 2.

[0020] As in Fig. As shown in Figure 2, the upper cover 5 and the upper frame 4 are connected at a connecting section 66 with an adhesive or the like, and the lower cover 5 and the lower frame 4 are also connected with an adhesive or the like in such a way as to maintain watertightness. This forms a water passage that covers the heat dissipation element 3 and the frame 4 with the cover. An inlet pipe 58, which serves as an inlet for cooling water, is also installed in a lower water passage W1, and an outlet pipe 59, which serves as an outlet for cooling water, is installed in an upper water passage W2. Furthermore, the connecting section 10 is connected in such a way that watertightness is maintained by a second sealing element 13 and connects the lower water passage W1 and the upper water passage W2.

[0021] The cooling water is supplied from the inlet pipe 58, flows through the heat dissipation fins 8 of the lower water passage W1, then through the connecting section 10, is supplied to the upper water passage W2, flows through the heat dissipation fins 8 in the upper water passage W2, and is then discharged from the outlet pipe 59. The flow of cooling water shown here is an example and is not limited to this.

[0022] The frame 4 is formed with the opening 41 into which the heat dissipation element 3 is fitted. A first sealing element 12 is provided between the inner circumference of the opening 41 and the outer circumference of the heat dissipation element 3. After the heat dissipation element 3 is fitted, the space between the heat dissipation element 3 and the opening 41 is sealed by the first sealing element 12 to maintain watertightness. The first sealing element 12 is an elastic element, such as rubber, for example an O-ring or the like.

[0023] The cover 5 also includes a fastening section 51 upon which a compressive force is exerted, a pressure section 52 connected to the tip of the heat dissipation fin 8, and an elastic section 53 provided between the fastening section 51 and the pressure section 52. The cover 5 is, for example, a plate-like element made of aluminum or the like, exhibiting high heat transfer performance, wherein the fastening section 51 is formed in a convex section, the pressure section 52 is formed in a concave section, and the elastic section 53 is formed in an inclined section connecting the fastening section 51 of the convex section and the pressure section 52 of the concave section.

[0024] Furthermore, a fastening element 11, shown in a simplified manner, is arranged in the fastening section 51. In the example of Fig. In this case, the mounting sections 51 are fixed between the semiconductor modules 2, arranged in parallel and furthermore fixed at both ends of the power conversion device 1, with the fastening elements 11 being arranged on the respective mounting sections 51. The fastening element 11 exerts a compressive force on the mounting section 51. In addition, the fastening element 11 secures the heat dissipation element 3, the frame 4, the cover 5, and the like, which are mounted on both surfaces of the semiconductor module 2, to both surfaces. The fastening element 11 is formed, for example, by attaching a bolt, which penetrates from the upper cover 5, to the lower cover 5 with a nut.In this case, the bolt penetrates the water passage, the frame 4, and the substrate 6, but is designed in such a way as to ensure the watertightness of the water passage and the insulation of the substrate 6. Likewise, the fastening element 11 is not limited to bolt fastening, so that a compressive force can also be exerted from the outside of the cover 5 by means of a leaf spring or the like. Furthermore, a spacer can be installed between the stacked frame 4, the substrate 6, and the like to adjust the compressive force of the fastening element 11.

[0025] An inner side (the side of the water passages W1 and W2) of the pressure section 52 is further connected to the tip of the heat dissipation fin 8 by a soldering material 81 or the like. The elastic section 53 also exhibits a higher elastic performance or deformation performance than the mounting section 51 and the pressure section 52 and pre-tensions the pressure section 52, in other words, the heat dissipation element 3 connected to the pressure section 52, by means of the compressive force exerted on the mounting section 51 in the direction of the heat dissipation surface of the semiconductor module 2.

[0026] The heat dissipation element 3 is further fitted into the opening 41 of the frame 4 via the first sealing element 12. The first sealing element 12 is, for example, an elastic element such as rubber, whereby the heat dissipation element 3 can be displaced towards the heat dissipation surface of the semiconductor module 2 by the pressure force exerted on the mounting section 51.

[0027] Fig. 3(a) to Fig. Figure 3(d) shows cross-sectional views illustrating an assembly process of the power conversion device 1 according to the embodiment. For ease of understanding, this drawing is described based on an enlarged view corresponding to area B, which is indicated by a dashed line in Fig. 2 is displayed, which is part of the power conversion device 1.

[0028] As in Fig. As illustrated in Figure 3(a), in step 1 the inner surface of the printed section 52 of the cover 5 and the tip of the heat dissipation fin 8 are joined by the solder material 81 or the like. The bonding is expediently carried out using an element with high thermal conductivity, preferably by soldering, ultrasonic waves, or the like, although the bonding method is not limited to these. By joining the heat dissipation element 3 to the cover 5, the heat transfer from the tip of the heat dissipation fin 8 to the cover is promoted, and the heat dissipation performance of the power conversion device 1 is improved.

[0029] Next, in step 2, as in Fig. Figure 3(b) illustrates that after the cover 5, to which the heat dissipation element 3 is connected, and the frame 4 with the formed opening 41 have been brought close together, the heat dissipation element 3 is fitted into the opening 41. Prior to this fitting, the first sealing element 12, such as an O-ring, is installed on the side surface of the base of the heat dissipation element 3, which is connected to the cover 5, and the second sealing element 13, such as an O-ring, is installed on the connecting section 10 between the lower water passage and the upper water passage. An adhesive or the like is applied beforehand to the connecting section 66 between the frame 4 and the cover 5. The frame 4 also has an opening 41 into which the heat dissipation element 3 is fitted in the direction of the frame 4.In other words, the opening 41 of the frame 4 is designed such that the heat dissipation element 3 is removable in the direction of the cover 5.

[0030] Then the frame 4 is brought close to the cover 5, and the heat dissipation element 3 is fitted into the inner circumferential surface of the opening 41 over the first sealing element 12. This fitting closes the opening 41, and the frame 4 and the cover 5 are connected by the connecting section 66, thus maintaining watertightness. Although not illustrated, similarly, on the underside of the power conversion device 1, the cover 5, to which the heat dissipation element 3 is connected, and the frame 4, in which the opening 41 is formed, are brought close together, the heat dissipation element 3 is fitted into the opening 41, and the frame 4 and the cover 5 are connected by the connecting section 66.

[0031] Next, in step 3, as in Fig. Figure 3(c) illustrates that the heat dissipation element 3 is brought into contact with the heat dissipation surfaces on both surfaces of the plurality of semiconductor modules 2 installed on the substrate 6 via the heat conduction element 7, and the connecting section 10 is connected via the second sealing element 13. Specifically, the substrate 6, on which the semiconductor module 2 is installed, is arranged on the lower frame 4, into which the heat dissipation element 3 is fitted, and subsequently the upper frame 4, into which the heat dissipation element 3 is fitted, is arranged on the substrate 6. In the drawings, the semiconductor modules 2 are also shown with varying thicknesses, assuming variations in the thickness of the semiconductor modules 2.

[0032] Next, in step 4, as in Fig. Figure 3(d) illustrates that the fastening element 11 is arranged on the mounting section 51 of the cover 5, and the heat dissipation element 3, the frame 4, the cover 5, and the like, which are mounted on both surfaces of the semiconductor module 2, are fixed by both surfaces. This fixation transfers the compressive force exerted on the mounting section 51 of the cover 5, via the elastic section 53, to the pressure section 52, and the heat dissipation element 3, which is connected to the inside of the pressure section 52, is pressed towards the semiconductor module 2. The heat dissipation element 3 is further supported by the frame 4 via the first sealing element 12, so that it is displaceable towards the heat dissipation surface of the semiconductor module 2.This means that the heat dissipation element 3, which is connected to the cover 5, can be pressed downwards towards the heat dissipation surface of the semiconductor module 2 by the elasticity of the elastic section 53 of the cover 5, and the heat dissipation element 3 itself can be moved towards the heat dissipation surface of the semiconductor module 2, since it is supported by the frame 4 over the first sealing element 12.

[0033] The amount of displacement of the heat dissipation element 3 is determined by the equilibrium between the compressive force of the fastening element 11, the reaction force of the elastic section 53, and the reaction force of the semiconductor module 2 and the heat-conducting element 7, i.e., the surface pressure. By setting the compressive force above a predetermined value, even in the semiconductor module 2 where the module thickness is relatively thin, the elastic section 53 is deformed until the surface pressure of the semiconductor module 2 reaches a predetermined value, and the heat dissipation element 3 is displaced. Consequently, the influence of variations in the thickness of the semiconductor module 2 and the like can be reduced, and the heat dissipation performance of the power conversion device 1 can be significantly improved. The effects of the present embodiment are further described below.

[0034] According to the present embodiment, the tip of the heat dissipation fin 8 and the cover 5 are joined by soldering, ultrasonic waves, or the like, thus promoting heat transfer from the tip of the heat dissipation fin 8 to the cover 5. As a result, the effective heat dissipation area, which contributes to heat dissipation to the cooling water, is increased at the cover 5, and the heat dissipation performance is improved.

[0035] Additionally, if the tip of the heat dissipation fin 8 and the cover 5 are connected, and the heat dissipation element 3 and the semiconductor module 2 are integrally assembled before connection, a high temperature can be introduced at the time of connection, potentially exceeding the thermal resistance temperature of the semiconductor module 2. Since the tip of the heat dissipation fin 8 and the cover 5 are connected before the semiconductor module 2 is mounted, there is no need to consider the thermal resistance temperature of the semiconductor module 2 at the time of connection in the present embodiment. Following connection, the first sealing element 12 is installed on the side surface of the base of the heat dissipation element 3 and fitted into the inner circumferential surface of the opening 41, thus ensuring watertightness while also improving ease of assembly.

[0036] Additionally, by using an elastic element, such as rubber, as the first sealing element 12, it is possible to absorb any misalignment between the heat dissipation element 3 and the opening 41 during assembly. Since the first sealing element 12 is deformable following the relative displacement between the outer circumference of the heat dissipation element 3 and the inner circumference of the opening 41, the positional deviation can be absorbed as long as it remains within the permissible range of the minimum compression required to ensure the watertightness of the opening 41.

[0037] Furthermore, in the present embodiment, the heat dissipation element 3, which is connected to the cover 5, is pressed towards the heat dissipation surface of the semiconductor module 2 by the elasticity of the elastic section 53 of the cover 5 and the displacement of the first sealing element 12. In contrast, in a case where the present embodiment is not used, for example, where the heat dissipation element 3 is integrally attached to the frame 4, excessive force is exerted on the semiconductor module 2 if the semiconductor module 2 is thick due to variations in its manufacturing, which causes damage to the semiconductor module 2.On the other hand, if the semiconductor module 2 is thin, the thermal resistance between the heat dissipation surface of the semiconductor module 2 and the heat dissipation element 3 increases, and the heat dissipation performance of the power conversion device 1 deteriorates. Furthermore, a similar problem exists in the power conversion device 1, in which a plurality of semiconductor modules 2 are provided in parallel, due to variations in the thickness of the semiconductor modules 2. According to the present embodiment, even if the thickness of the semiconductor module 2 varies, the surface pressure on the semiconductor module 2 is maintained uniformly, and the heat dissipation surface of the semiconductor module 2 and the thermal contact resistance of the heat conduction element 7 can be kept low.Furthermore, even if the heat dissipation element 3 is moved, since the tip of the heat dissipation fin 8 and the cover 5 are connected, the thickness of the water passage does not change and the flow of cooling water is not obstructed.

[0038] It should be noted that the thickness of the elastic section 53 of the cover 5 can be thinner than other sections of the cover 5. Reducing the thickness of the elastic section 53 increases the amount of elastic deformation, and the area in which variations in the thickness of the semiconductor module 2 can be tracked can also be increased. Consequently, in a case where the multiple semiconductor modules 2 are arranged in parallel, even if the variation in the thickness of the multiple semiconductor modules 2 is large, each heat dissipation element 3 is deformed up and down according to the variation in the thickness of the semiconductor modules 2, the surface pressure on the semiconductor modules 2 is kept uniform, and the heat dissipation surface area of ​​the semiconductor modules 2 and the thermal contact resistance of the heat-conducting element 7 can be kept low. (First modification)

[0039] Fig. Figure 4 is an enlarged cross-sectional view of a power conversion device 1 according to a first modification. This enlarged cross-sectional view corresponds to a cross-section along the line AA' in Fig. 1 and is a section corresponding to area B, which is marked by a dashed line in Fig. 2 is displayed, similar to Fig. 3(d). The same sections as those in Fig. 3(d) are designated with the same reference symbols, and their description is briefly given again.

[0040] As in Fig. As shown in Figure 4, the elastic section 53 of the cover 5 in the first modification has a bellows structure. The elastic section 53 with the bellows structure increases the amount of elastic deformation of the elastic section 53.

[0041] According to the first modification, it is possible to increase the area in which the variation in the thickness of the semiconductor module 2 can be tracked, to maintain the surface pressure with respect to the heat dissipation surface of the semiconductor module 2, and to keep the thermal contact resistance with the heat dissipation surface and the thermal conducting element 7 low. (Second modification)

[0042] Fig. Figure 5 is an enlarged cross-sectional view of a power conversion device 1 according to a second modification. This enlarged cross-sectional view corresponds to a cross-section along line AA' in Fig. 1 and is a section corresponding to area B, which is marked by a dashed line in Fig. 2 is displayed, similar to Fig. 3(d). The same sections as those in Fig. 3(d) are here designated with the same reference symbols, and their description is briefly given again.

[0043] As in Fig. As shown in Figure 5, in the second modification grooves 54 are provided for positioning the heat dissipation fins 8 within the pressure section 52 of the cover 5. The tip of the heat dissipation fin 8 is fitted into the groove 54 and connected to it.

[0044] According to the second modification, the tip of the heat dissipation rib 8 is also fitted into and connected to the groove 54, thus reducing the variation in its relative position with respect to the opening 41 of the frame 4 during assembly, thereby improving ease of assembly. Furthermore, heat transfer from the tip of the heat dissipation rib 8 to the cover 5 is further enhanced, increasing the effective heat dissipation area that contributes to heat transfer to the cooling water and improving heat dissipation performance. Additionally, by limiting the section to be connected to the groove 54, the amount of solder required for soldering can be reduced, and an increase in flow resistance due to the inflow of solder 81 between the heat dissipation ribs 8 can be suppressed. (Third modification)

[0045] Fig. Figure 6 is an enlarged cross-sectional view of a power conversion device 1 according to a third modification. This enlarged cross-sectional view corresponds to a cross-section along line AA' in Fig. 1 and is a section corresponding to area B, which is marked by a dashed line in Fig. 2 is displayed, similar to Fig. 3(d). The same sections as those in Fig. 3(d) are designated with the same reference symbols, and their description is briefly given again.

[0046] As in Fig. As shown in Figure 6, in the third modification a projection 82 is provided at the tip of the heat dissipation rib 8, and the groove 54 is provided within the pressure section 52 of the cover 5 on a surface to which the projection 82 of the heat dissipation rib 8 is connected. Projections 84 of the heat dissipation ribs 8 are also fitted into and connected to the grooves 54 of the cover.

[0047] According to the third modification, the projection 82 is further fitted into the groove 54 at the tip of the heat dissipation rib 8 and connected to it, thus reducing the variation in its relative position with respect to the opening 41 of the frame during assembly with the frame 4, thereby further improving ease of assembly. In addition, heat transfer from the tip of the heat dissipation rib 8 to the cover 5 is promoted, the effective heat dissipation area contributing to heat transfer to the cooling water is increased, and the heat dissipation performance is improved. Furthermore, by limiting the section to be connected to the groove 54, the amount of solder required for soldering can be reduced, and an increase in flow resistance due to the inflow of solder between the heat dissipation ribs 8 can be suppressed.

[0048] In contrast to the configuration of the third modification, the same effect can also be achieved by providing the groove at the tip of the heat dissipation rib 8 and the projection within the pressure section 52 of the cover 5, and fitting the projection into the groove and connecting it to the groove. (Fourth modification)

[0049] Fig. Figure 7 is an enlarged cross-sectional view of a power conversion device 1 according to a fourth modification. This enlarged cross-sectional view corresponds to a cross-section along line AA' in Fig. 1 and is a section corresponding to area B, which is marked by a dashed line in Fig. 2 is displayed, similar to Fig. 3(d). The same sections as those in Fig. 3(d) are designated with the same reference symbols, and their description is briefly given again.

[0050] As in Fig.As shown in Figure 7, in the fourth modification a groove 55 is formed for holding the solder material 81 within the pressure section 52 of the cover 5. The groove 55 has a width capable of holding the solder material 81 by capillary action, although its shape is not limited to this.

[0051] According to the fourth modification, in a case where the tip of the heat dissipation fin 8 and the inside of the pressure section 52 are joined by soldering, the solder material 81 can be retained in a suitable quantity by capillary action, and excess solder material 81 is prevented from flowing out between the heat dissipation fin 8 and the heat dissipation fin 8. As a result, it is possible to prevent a deterioration in the heat dissipation performance of the power conversion device 1 without impeding the circulation of the cooling water.

[0052] According to the above embodiment, the following effects are achieved. (1) A cooling structure of a power conversion device 1 comprises a semiconductor module 2, which includes a semiconductor element and has a heat dissipation surface on at least one surface; a heat dissipation element 3, which is thermally connected to the heat dissipation surface of the semiconductor module 2 and has a heat dissipation fin 8; a frame 4, which supports the heat dissipation element 3;and a cover 5 that covers the heat dissipation element 3 and the frame 4 to form water passages W1 and W2 through the heat dissipation fin 8, the frame 4 having an opening 41 into which the heat dissipation element 3 is fitted in the direction of the frame 4, and a space between the fitted heat dissipation element 3 and the opening 41 being closed by a sealing element 12, and the heat dissipation element 3 being connected to the cover 5 at a tip of the heat dissipation fin 8 and being configured to be displaceable by a pressure force exerted on the cover 5 in the direction of the heat dissipation surface of the semiconductor module 2. Accordingly, the heat dissipation performance of the power conversion device can be improved.

[0053] The present invention is not limited to the embodiments described above and includes other forms that fall within the scope of the technical ideas of the present invention, provided that the features of the present invention are not impaired by them. Furthermore, the embodiments described above and the multitude of modifications can be combined. Reference symbol list 1 Power conversion device 2, 21 to 26 Semiconductor module 3, 31 to 36 Heat dissipation element 4 frames 5 Cover 6 Substrat 8 heat dissipation fins 10 Connecting section 11 Fastening element 12 first sealing element 13 second sealing element 41 Opening 51 Fastening section 52 Print section 52 elastic section 54, 55 Nut 58 Inlet pipe 59 Outlet pipe 66 Connecting section 81 Soldering material 82 lead W1, W2 Water passage QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2019-160832 A

[0004]

Claims

[1] A cooling structure for a power conversion device comprising: a semiconductor module incorporating a semiconductor element and having a heat dissipation surface on at least one surface; a heat dissipation element thermally connected to the heat dissipation surface of the semiconductor module and having a heat dissipation fin; a frame supporting the heat dissipation element; and a cover covering the heat dissipation element and the frame to form a water passage through the heat dissipation fin, wherein the frame has an opening into which the heat dissipation element is fitted in the direction of the frame, and a space between the fitted heat dissipation element and the opening is closed by a sealing element, and The heat dissipation element is connected to the cover at one tip of the heat dissipation rib and is configured to be displaceable towards the heat dissipation surface of the semiconductor module by a pressure force applied to the cover. [2] The cooling structure of the power conversion device according to claim 1, wherein the cover includes an elastic section which prestresses the cover in the direction of the heat dissipation surface by the pressure force applied to the cover. [3] The cooling structure of the power conversion device according to claim 2, wherein the cover is formed from a plate-shaped element, and The thickness of the elastic section is thinner than the thickness of the cover. [4] The cooling structure of the power conversion device according to claim 2, wherein the elastic section has a bellows structure. [5] The cooling structure of the power conversion device according to claim 1, wherein the cover includes a fastening section on which the compressive force is applied, a pressure section connected to a tip of the heat dissipation fin, and an elastic section provided between the fastening section and the pressure section, and The elastic section prestresses the pressure section in the direction of the heat dissipation surface through the compressive force exerted on the fastening section. [6] The cooling structure of the power conversion device according to claim 1, wherein the sealing element is provided between an inner circumference of the opening and an outer circumference of the heat dissipation element and is configured by an elastic element with which the heat dissipation element is displaced by the pressure force in the direction of the heat dissipation surface of the semiconductor module. [7] The cooling structure of the power conversion device according to claim 1, wherein a groove in the cover, into which the tip of the heat dissipation fin is fitted, is formed on a surface to which the tip of the heat dissipation fin is connected. [8] The cooling structure of the power conversion device according to claim 1, wherein a groove is formed in the cover for holding a solder material on a surface to which the tip of the heat dissipation fin is connected. [9] The cooling structure of the power conversion device according to claim 1, wherein a projection is provided at the top of the heat dissipation fin, and The cover has a groove on a surface to which the tip of the heat dissipation rib is connected, and the projection of the heat dissipation rib is fitted into the groove of the cover. [10] The cooling structure of the power conversion device according to any one of claims 1 to 9, wherein a large number of semiconductor modules are provided in parallel, the coverage covers the multitude of semiconductor modules, the frame is designed with respective openings into which respective heat dissipation elements, which are provided according to the respective heat dissipation surfaces of the multitude of semiconductor modules, are fitted, and Each of the heat dissipation elements is configured to be displaceable by a pressure force applied to the cover in the direction of the heat dissipation surface of each of the semiconductor modules. [11] The cooling structure of the power conversion device according to any one of claims 1 to 9, wherein In the semiconductor module, the heat dissipation surface is formed on both surfaces of the semiconductor element. the heat dissipation element is arranged on both surfaces of the semiconductor module, so that it faces the heat dissipation surface, the frame is arranged on both surfaces to support a heat dissipation element, and The cover covers the heat dissipation element and the frame to form a water passage that runs through the heat dissipation rib on both surfaces.

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