Power conversion device

Abstract

A power conversion device (1) comprises: at least one semiconductor module (40) having one or more semiconductor elements (42); and a cooler (11) having a flow path (14) through which refrigerant flows to cool the semiconductor module (40). The semiconductor module (40) and the cooler (11) are thermally connected via a bonding member (50). The cooler (11) has one or more protruding portions (16, 17) extending into the flow path (14) from the side surface portion of the flow path (14) on the semiconductor module (40) side. The protruding portions (16, 17) have recessed portions (16a, 17a) that open toward the semiconductor module (40) side, which is the side opposite to the flow path (14) side. The semiconductor module (40) has positioning pins (45) that are inserted into the recessed portions (16a, 17a) and project toward the cooler (11). The semiconductor module (40) is positioned relative to the cooler (11) by the positioning pins (45).

Description

Power Conversion Device

[0001] The present disclosure relates to a power conversion device.

[0002] Electrically powered vehicles that use a motor as a drive source, such as electric vehicles or hybrid vehicles, are equipped with multiple power conversion devices. Examples of power conversion devices include a charger that converts a commercial AC power source into DC power to charge a high-voltage battery, a DC / DC converter that converts the DC power of the high-voltage battery into a voltage (e.g., 12 V) for a battery for auxiliary equipment, and an inverter that converts DC power from the battery into AC power for the motor.

[0003] A known power conversion device includes a semiconductor module mounted with semiconductor elements that perform power conversion, and a cooler that cools the semiconductor module. To achieve a smaller semiconductor module and higher output, the cooling performance of the semiconductor module may be improved by thermally connecting the semiconductor module to the cooler via solder or a heat dissipation member. In this case, to achieve effective cooling performance, the semiconductor module must be positioned relative to the cooler and mounted at a specified position on the cooler.

[0004] A configuration has been proposed in which a semiconductor module is mounted at a specified position on a cooler (see, for example, Patent Document 1). In Patent Document 1, protrusions and recesses are alternately provided on both sides of the portion that thermally connects the semiconductor module and the cooler, thereby positioning the semiconductor module relative to the cooler.

[0005] International Publication No. 2018 / 079396

[0006] To achieve miniaturization and high output of semiconductor modules, it is effective to shorten the distance between the semiconductor module and the refrigerant as much as possible to reduce thermal resistance between the semiconductor module and the refrigerant and improve the cooling performance of the semiconductor module. In the above-mentioned Patent Document 1, heat dissipation fins are provided on the side of the cooler opposite the semiconductor module, so it is desirable to shorten the distance between the semiconductor module and the refrigerant as much as possible. In the above-mentioned Patent Document 1, the protrusions and recesses are provided alternately, so the semiconductor module can be positioned relative to the cooler. However, to improve the accuracy of positioning the semiconductor module and the cooler, the shapes of the protrusions and recesses need to be elongated to a certain extent in the direction in which the semiconductor module and the cooler overlap. If the shapes of the protrusions and recesses are elongated in the direction in which the semiconductor module and the cooler overlap, the distance between the refrigerant or the heat dissipation fins and the semiconductor module increases, which poses a problem of reduced heat dissipation performance of the semiconductor module.

[0007] Furthermore, the above-mentioned Patent Document 1 describes that by thermally connecting the semiconductor module and the cooler using a protrusion and recess formed continuously on each side of the semiconductor module and the cooler, misalignment of the connection and the mating surfaces are less likely to occur. However, due to variations in the dimensions of the protrusion and recess, some of the protrusion and recess may not make contact. In such cases, variations in the contact position also occur, resulting in insufficient positioning accuracy between the semiconductor module and the cooler. If the contact area between the protrusion and recess on the semiconductor module side and the cooler side becomes small, the heat transfer area from the semiconductor module to the cooler becomes small, resulting in a problem of the heat dissipation performance of the semiconductor module being lower than the predetermined design value.

[0008] Therefore, an object of the present disclosure is to provide a power conversion device in which a semiconductor module is positioned relative to a cooler without reducing the heat dissipation performance of the semiconductor module.

[0009] The power conversion device of the present disclosure comprises one or more semiconductor modules each having one or more semiconductor elements, and a cooler having a flow path inside which a refrigerant flows and cooling the semiconductor module, wherein the semiconductor module and the cooler are thermally connected via a joining member, the cooler has one or more protrusions protruding into the flow path from a side portion of the flow path on the semiconductor module side, the protrusions having a recess on the opposite side to the flow path that opens towards the semiconductor module, the semiconductor module has a positioning pin that protrudes towards the cooler and is inserted into the recess, and the semiconductor module is positioned relative to the cooler by the positioning pin.

[0010] According to the power conversion device disclosed herein, there is provided a power conversion device including one or more semiconductor modules each having one or more semiconductor elements, and a cooler having a flow path through which a refrigerant flows and configured to cool the semiconductor module, the semiconductor module and the cooler being thermally connected to each other via a bonding member, the cooler having one or more protrusions extending from a side portion of the flow path adjacent to the semiconductor module into the flow path, the protrusions having a recessed portion opposite the flow path and opening toward the semiconductor module, the semiconductor module having a positioning pin protruding toward the cooler and inserted into the recessed portion, the semiconductor module being positioned relative to the cooler by the positioning pin, and therefore, unlike Patent Document 1, there is no protrusion and recess formed between the semiconductor module and the cooler, and the distance between the semiconductor module and the refrigerant is reduced, thereby enabling the semiconductor module to be positioned relative to the cooler without degrading the heat dissipation performance of the semiconductor module. Furthermore, if the length of the positioning pin is extended toward the cooler to improve positioning accuracy, the protrusions can be lengthened without changing the distance between the semiconductor module and the refrigerant, thereby enabling the semiconductor module to be positioned accurately relative to the cooler without degrading the heat dissipation performance of the semiconductor module.

[0011] 1 is a side view showing an outline of a power converter according to embodiment 1. FIG. 2 is a cross-sectional view showing an outline of a power converter according to embodiment 1. FIG. 3 is a plan view showing an outline of flow paths of the power converter according to embodiment 1. FIG. 4 is a plan view showing an outline of another flow path of the power converter according to embodiment 1. FIG. 5 is a plan view showing an outline of another flow path of the power converter according to embodiment 1. FIG. 6 is a view explaining an arrangement of protrusions of the power converter according to embodiment 1. FIG. 7 is a plan view showing an outline of a power converter according to embodiment 2. FIG. 8 is a plan view showing an outline of flow paths of the power converter according to embodiment 2. FIG. 9 is a plan view showing an outline of flow paths of another power converter according to embodiment 2. FIG. 10 is a plan view explaining the flow of refrigerant in the flow paths of the power converter according to embodiment 2. FIG. 11 is a plan view explaining the flow of refrigerant in the flow paths of another power converter according to embodiment 2. FIG. 12 is a plan view explaining the flow of refrigerant around protrusions of the power converter according to embodiment 2. FIG. 13 is a plan view explaining the flow of refrigerant around another protrusion of the power converter according to embodiment 2. FIG. 14 is a cross-sectional view showing an outline of a power converter according to embodiment 3. FIG. 15 is a cross-sectional view showing an outline of another cooler of another power converter according to embodiment 3. Fig. 10 is a plan view illustrating an outline of a power converter according to a fourth embodiment;Fig. 11 is a plan view illustrating the flow of a coolant in a flow path of the power converter according to the fourth embodiment;

[0012] Hereinafter, a power conversion device according to an embodiment of the present disclosure will be described with reference to the drawings. Note that the same or equivalent members and parts in each drawing will be denoted by the same reference numerals.

[0013] 1 is a side view showing an outline of a power converter 1 according to a first embodiment, FIG. 2 is a cross-sectional view showing an outline of the power converter 1, taken along the line A-A in FIG. 3, FIG. 3 is a plan view showing an outline of a flow path 14 of the power converter 1, viewed from the inside of the flow path 14 toward the semiconductor module 40, FIG. 4 is a plan view showing an outline of another flow path 14 of the power converter 1 according to the first embodiment, viewed from the inside of the flow path 14 toward the semiconductor module 40, and FIG. 5 is a side view of a power converter according to the first embodiment. FIG. 1 is a plan view showing an outline of another flow path 14 of the power converter 1, as viewed from the inside of the flow path 14, and FIG. 6 is a diagram explaining the arrangement of the protrusions 16 and 17 of the power converter 1, with FIG. 6(a) being a cross-sectional view of the power converter 1 at a position equivalent to that of FIG. 2, and FIG. 6(b) being a plan view showing an outline of the flow path 14. FIG. 7 is a diagram explaining the arrangement of the protrusions 16 and 17 of the power converter 1, with FIG. 7(a) being a cross-sectional view of the power converter 1 at a position equivalent to that of FIG. 2, and FIG. 7(b) being a plan view showing an outline of the flow path 14. In FIGS. 3 to 5, the outline of the main body of the semiconductor module 40 is indicated by a dashed line. The power converter 1 is a device that converts input current from DC to AC, AC to DC, or converts input voltage to a different voltage. The power converter 1 is mounted on and used in an electric vehicle, such as a hybrid vehicle or an electric vehicle.

[0014] <Power Conversion Device 1> The power conversion device 1 includes one or more semiconductor modules 40 each having one or more semiconductor elements 42, and a cooler 11 having a flow path 14 through which a refrigerant flows and configured to cool the semiconductor module 40. As shown in FIG. 1 , the semiconductor module 40 and the cooler 11 are thermally connected via a bonding member 50. The bonding member 50 is, for example, a heat dissipation member such as solder or a heat dissipation sheet. In this embodiment, as shown in FIG. 2 , the power conversion device 1 includes one semiconductor module 40, and the semiconductor module 40 has two semiconductor elements 42. FIG. 2 shows the interior of the semiconductor module 40 through a mold resin 41. The number of semiconductor modules 40 and the number of semiconductor elements 42 are not limited thereto. The power conversion device 1 is, for example, an inverter that converts DC power supplied from an external power source into AC power and supplies the power to a load.

[0015] Two semiconductor elements 42 are bonded to a heat spreader 43. The semiconductor elements 42 and the heat spreader 43 are directly or indirectly connected to connection terminals 46. The connection terminals 46 are connected to an external power supply or a load (neither of which is shown). The heat spreader 43 is thermally connected to a heat spreader 51 via an insulating member 49. The heat spreader 43 and the connection terminals 46 are formed of sheet metal parts made of a metal material with excellent electrical conductivity. The heat spreader 51 is formed of a metal material with excellent thermal conductivity. These metal materials are, for example, copper. A portion of the connection terminals 46, the semiconductor elements 42, the heat spreader 43, the insulating member 49, and a portion of the heat spreader 51 are sealed in a molded resin 41. The portion of the connection terminals 46 connected to the external power supply or the load protrudes from the molded resin 41. The side of the heat spreader 51 facing the cooler 11 is exposed from the molded resin 41. Although the molded resin 41 is formed in a rectangular parallelepiped shape, the shape of the molded resin 41 is not limited to this.

[0016] In this embodiment, the cooler 11 is formed from a base 11a, which is a main body portion having an opening on the side opposite to the side where the semiconductor module 40 is provided, and a lid 13 covering the opening of the base 11a. The area surrounded by the base 11a and the lid 13 is a flow path 14. The lid 13 forms the bottom wall of the cooler 11. In this embodiment, the refrigerant flow direction 20 in the flow path 14 is from left to right in the figure, as indicated by the arrow. By forming the cooler 11 from the base 11a and the lid 13, the cooler 11 can be manufactured separately from the base 11a and the lid 13. This allows the base 11a, which has a complex configuration including the fins 12 and protrusions 16 and 17 described below, to be easily manufactured by die-casting or the like. The ease of manufacturing the cooler 11 from the base 11a and the lid 13 improves the productivity of the power conversion device 1. The lid 13 is fixed to the base 11a, for example, by screws, via a sealing member. The cooler 11 is made of, for example, aluminum, an aluminum alloy, copper, or a copper alloy. The coolant used may be, for example, water, ethylene glycol liquid, or LLC (long-life coolant). The portion of the lid 13 where the fins 12 and the protrusions 16 and 17 face each other is the facing surface 15.

[0017] In this embodiment, as shown in FIG. 1 , the cooler 11 has a cooling surface 11a1, and a bottom surface 40a, which is a flat surface on the cooler 11 side of the semiconductor module 40, is thermally connected to the cooling surface 11a1 via a bonding member 50. The portion where the bottom surface 40a and the cooling surface 11a1 are thermally connected is a bonding surface 44. With this configuration, there are no protrusions or recesses between the semiconductor module 40 and the cooler 11, as shown in Patent Document 1. This reduces the distance between the semiconductor module 40 and the refrigerant, thereby suppressing a decrease in the heat dissipation performance of the semiconductor module 40. Furthermore, providing the bonding member 50 can improve the heat dissipation performance of the semiconductor module 40.

[0018] <Protrusions 16, 17> The positioning of the semiconductor module 40 relative to the cooler 11 using the protrusions 16, 17, which are a key part of the present disclosure, will now be described. The cooler 11 has one or more protrusions protruding into the flow path 14 from a side portion of the flow path 14 on the semiconductor module 40 side. The protrusions have a recess that opens to the semiconductor module 40 side on the opposite side from the flow path 14, and the semiconductor module 40 has a positioning pin 45 that protrudes toward the cooler 11 and is inserted into the recess. The semiconductor module 40 is positioned relative to the cooler 11 by the positioning pin 45.

[0019] In the configurations shown in Figures 3, 4, and 5, the cooler 11 has two protrusions 16, 17. The protrusion 16 has a recess 16a, and the protrusion 17 has a recess 17a. The number of protrusions is not limited to this and may be one or three or more. In this embodiment, the shape of the recesses 16a, 17a when viewed in the direction of inserting the positioning pin 45 is circular or elongated. The cross section perpendicular to the insertion direction of the positioning pin 45 is circular. When a single protrusion is provided, it is desirable that the shape of the recesses 16a, 17a when viewed in the direction of inserting the positioning pin 45 and the cross section of the positioning pin 45 be, for example, rectangular, cross-shaped, or diamond-shaped. With this configuration, the semiconductor module 40 does not rotate around the positioning pin 45 as a fulcrum, so even with a single protrusion, the semiconductor module 40 can be positioned relative to the cooler 11.

[0020] By positioning the semiconductor module 40 relative to the cooler 11 using the protrusions 16 and 17 protruding toward the flow path 14 and the positioning pin 45 provided on the semiconductor module 40, there are no protrusions and recesses between the semiconductor module 40 and the cooler 11 as shown in Patent Document 1, and therefore the distance between the semiconductor module 40 and the refrigerant is reduced, allowing the semiconductor module 40 to be positioned relative to the cooler 11 without reducing the heat dissipation performance of the semiconductor module 40. Furthermore, when the length of the positioning pin 45 is extended toward the cooler 11 to improve positioning accuracy, it is sufficient to lengthen the protrusions 16 and 17 without changing the distance between the semiconductor module 40 and the refrigerant, and therefore the semiconductor module 40 can be positioned relative to the cooler 11 with high accuracy without reducing the heat dissipation performance of the semiconductor module 40.

[0021] In Fig. 4, the shapes of the recesses 16a, 17a are both circular when viewed in the direction of inserting the positioning pin 45. In Figs. 3 and 5, when viewed in the direction of inserting the positioning pin 45, one of the recesses 16a, 17a is circular and the other is elongated. In consideration of the dimensional tolerance of the arrangement of the positioning pin 45, it is desirable to provide protrusions of different shapes like this. The protrusions of different shapes will be described in detail later.

[0022] In this embodiment, the coolant flows through the flow path 14 from one side, which is the upstream side, to the other side, which is the downstream side, relative to the semiconductor module 40. In the figure, the left side is the upstream side, and the right side is the downstream side. In this embodiment, one or more protrusions are provided on one or both of the portion of the cooler 11 upstream of the semiconductor module 40 and the portion of the cooler 11 downstream of the semiconductor module 40. In the configurations shown in FIGS. 3 and 4, a single protrusion is provided on each of the portion of the cooler 11 upstream of the semiconductor module 40 and the portion of the cooler 11 downstream of the semiconductor module 40. A protrusion 16 is provided on the upstream side, and a protrusion 17 is provided on the downstream side. In the configuration shown in FIG. 5, a plurality of protrusions, 16 and 17, are provided on the portion of the cooler 11 upstream of the semiconductor module 40.

[0023] At the locations where the protrusions are provided, the distance between the semiconductor module 40 and the refrigerant increases due to the protrusions being sandwiched between them, which reduces the heat dissipation performance of the semiconductor module 40. With this configuration, the protrusions are provided at positions away from the center of the semiconductor module 40, so the semiconductor module 40 can be accurately positioned relative to the cooler 11 without interfering with the heat dissipation performance of the semiconductor module 40.

[0024] In this embodiment, the cooler 11 has a plurality of fins 12 that protrude into the flow path 14 from a portion where the semiconductor module 40 is thermally connected, and the protrusions 16, 17 are provided at a distance from the plurality of fins 12. By providing the plurality of fins 12, the heat of the semiconductor module 40 can be efficiently dissipated to the refrigerant. Furthermore, by providing the protrusions 16, 17 at a distance from the plurality of fins 12, the flow of the refrigerant passing around the plurality of fins 12 is not obstructed by the protrusions 16, 17, and heat dissipation by the plurality of fins 12 is not inhibited, so the heat of the semiconductor module 40 can be efficiently dissipated to the refrigerant.

[0025] In this embodiment, the distance between a protrusion and a fin adjacent to the protrusion is greater than the distance between two adjacent fins. In FIG. 3 , the distance between a protrusion 16 and a fin 12 adjacent to the protrusion 16 is the protrusion-fin distance 19, and the distance between two adjacent fins is the fin-to-fin distance 18. The protrusion-to-fin distance 19 is greater than the fin-to-fin distance 18. With this configuration, the multiple fins 12 are densely arranged in a concentrated manner, efficiently dissipating heat from the semiconductor module 40 to the coolant. Furthermore, since the protrusions are reliably spaced apart from the multiple fins 12, the flow of the coolant in the area where the multiple fins 12 are arranged is not impeded and heat dissipation by the multiple fins 12 is not suppressed, allowing the heat from the semiconductor module 40 to be more efficiently dissipated to the coolant.

[0026] In this embodiment, as shown in FIG. 6( a), the semiconductor element 42 is disposed facing the flow path 14, and the protrusions are not provided in the element projection area 27, which is the area of ​​the flow path 14 where the semiconductor element 42 is projected onto the flow path 14. The element projection area 27 is the area surrounded by a dashed line in FIG. 6( b). The protrusions 16, 17 are not provided in the element projection area 27. Of the components provided in the semiconductor module 40, the semiconductor element 42 is the component that is most likely to generate heat. Therefore, by efficiently dissipating the heat from the semiconductor element 42, the power conversion efficiency of the power conversion device 1 can be improved. In the configuration shown in FIG. 6( b), the protrusions 16, 17 are not provided in the element projection area 27, and therefore the heat dissipation from the semiconductor element 42 is not hindered by the protrusions 16, 17. Therefore, the heat dissipation from the semiconductor element 42 by the multiple fins 12 is not inhibited, and therefore the heat from the semiconductor element 42 can be efficiently dissipated to the refrigerant.

[0027] A configuration that can more efficiently dissipate heat from the semiconductor element 42 to the refrigerant will be described with reference to FIGS. 7A and 7B. As shown in FIG. 7A, the semiconductor element 42 is disposed facing the flow path 14, and the protrusions are not provided in an element projection area 27, which is the area of ​​the flow path 14 when the semiconductor element 42 is projected onto the flow path 14, or in an area obtained by adding the distance from the semiconductor element 42 to the semiconductor element 42 side of the flow path 14 to the periphery of the element projection area 27. It is assumed that heat generated in the semiconductor element 42 diffuses from the semiconductor element 42 to the refrigerant at a 45-degree angle relative to the projection line 21 when the semiconductor element 42 is projected onto the flow path 14. The area where heat diffuses at a 45-degree angle in the flow path 14 is the area obtained by adding the distance from the semiconductor element 42 to the semiconductor element 42 side of the flow path 14 to the periphery of the element projection area 27. This region is called a diffusion region 27a, and is indicated by a dashed line around the element projection region 27 in FIG. 7(b).

[0028] 7B, the protrusions 16, 17 are not provided in the element projection area 27 and the diffusion area 27a. With this configuration, since the protrusions 16, 17 are not provided in the element projection area 27 and the diffusion area 27a, heat dissipation from the semiconductor element 42 is not hindered by the protrusions 16, 17, including the diffusion area 27a, and therefore heat dissipation from the semiconductor element 42 by the multiple fins 12 is not further suppressed, so that the heat from the semiconductor element 42 can be dissipated to the refrigerant more efficiently.

[0029] As described above, in the power conversion device 1 according to embodiment 1, the cooler 11 has one or more protrusions protruding into the flow path 14 from the side portion of the flow path 14 on the semiconductor module 40 side, and the protrusions have a recess on the opposite side of the flow path 14 that opens toward the semiconductor module 40, the semiconductor module 40 has a positioning pin 45 that protrudes toward the cooler 11 and is inserted into the recess, and the semiconductor module 40 is positioned relative to the cooler 11 by the positioning pin 45. Therefore, no protrusions or recesses as shown in Patent Document 1 are formed between the semiconductor module 40 and the cooler 11, and the distance between the semiconductor module 40 and the refrigerant is reduced, so that the semiconductor module 40 can be positioned relative to the cooler 11 without reducing the heat dissipation performance of the semiconductor module 40. Furthermore, when the length of the positioning pin 45 is extended toward the cooler 11 to improve the positioning accuracy, the protrusions 16 and 17 can be lengthened without changing the distance between the semiconductor module 40 and the refrigerant, so that the semiconductor module 40 can be positioned accurately relative to the cooler 11 without reducing the heat dissipation performance of the semiconductor module 40.

[0030] When the refrigerant flows through the flow path 14 from one side, which is the upstream side, to the other side, which is the downstream side, relative to the semiconductor module 40, and when one or more protrusions are provided on one or both of the part of the cooler 11 upstream of the semiconductor module 40 and the part of the cooler 11 downstream of the semiconductor module 40, the distance between the semiconductor module 40 and the refrigerant increases at the location where the protrusions are provided, thereby reducing the heat dissipation performance of the semiconductor module 40. However, since the protrusions are provided at a position away from the center of the semiconductor module 40, the semiconductor module 40 can be accurately positioned relative to the cooler 11 without interfering with the heat dissipation performance of the semiconductor module 40.

[0031] When the cooler 11 has a plurality of fins 12 protruding into the flow path 14 from the portion to which the semiconductor module 40 is thermally connected, and the protrusions 16, 17 are spaced apart from the plurality of fins 12, the flow of the refrigerant passing around the plurality of fins 12 is not obstructed by the protrusions 16, 17, so heat dissipation by the plurality of fins 12 is not suppressed, and the heat of the semiconductor module 40 can be efficiently dissipated into the refrigerant.

[0032] When the distance between a protrusion and a fin adjacent to the protrusion is greater than the distance between two adjacent fins, the multiple fins 12 are arranged densely together, allowing the heat of the semiconductor module 40 to be efficiently dissipated into the refrigerant, and the protrusions are reliably arranged at a distance from the multiple fins 12, so the flow of refrigerant in the area where the multiple fins 12 are arranged is not obstructed and heat dissipation by the multiple fins 12 is not suppressed, allowing the heat of the semiconductor module 40 to be dissipated into the refrigerant even more efficiently.

[0033] When the semiconductor element 42 is arranged opposite the flow path 14 and the protrusions are not arranged in the element projection area 27, which is the area of ​​the flow path 14 where the semiconductor element 42 is projected onto the flow path 14, the heat dissipation of the semiconductor element 42, which is a heat-generating component, is not hindered by the protrusions 16, 17, so the heat dissipation of the semiconductor element 42 by the multiple fins 12 is not suppressed and the heat of the semiconductor element 42 can be efficiently dissipated into the refrigerant.

[0034] When the semiconductor element 42 is arranged opposite the flow path 14 and the protrusions are not provided in the element projection area 27, which is the area of ​​the flow path 14 where the semiconductor element 42 is projected onto the flow path 14, and in the area obtained by adding the distance from the semiconductor element 42 to the side of the flow path 14 on which the semiconductor element 42 is located to the periphery of the element projection area 27, the heat dissipation of the semiconductor element 42, which is a heat-generating component, is not hindered by the protrusions 16, 17, including the diffusion area 27a, so that the heat dissipation of the semiconductor element 42 by the multiple fins 12 is not further suppressed and the heat of the semiconductor element 42 can be dissipated to the refrigerant more efficiently.

[0035] Embodiment 2. A power conversion device 1 according to embodiment 2 will be described. Fig. 8 is a plan view showing an outline of the power conversion device 1 according to embodiment 2, showing only a portion corresponding to a flow path 14 that cools one semiconductor module 40, Fig. 9 is a plan view showing an outline of the flow path 14 of the power conversion device 1, viewed from inside the flow path 14 toward the semiconductor module 40, Fig. 10 is a plan view showing an outline of another flow path 14 of the power conversion device 1, viewed from inside the flow path 14 toward the semiconductor module 40, Fig. 11 is a plan view illustrating the flow of refrigerant in the flow path 14 of the power conversion device 1, viewed from inside the flow path 14 toward the semiconductor module 40, Fig. 12 is a plan view illustrating the flow of refrigerant in the flow path 14 of another power conversion device 1, viewed from inside the flow path 14 toward the semiconductor module 40, Fig. 13 is a plan view illustrating the flow of refrigerant around a protrusion 16 of the power conversion device 1, and Fig. 14 is a plan view illustrating the flow of refrigerant around a protrusion 17 of the power conversion device 1. The power conversion device 1 according to the second embodiment has a configuration in which the shape and arrangement of the protrusions are specified.

[0036] The protrusions extend in a direction perpendicular to the direction of coolant flow. When a single protrusion is provided on one or both of the upstream and downstream sides of a single semiconductor module 40, the outer diameter of the protrusion in a flow path perpendicular direction, which is perpendicular to the direction of coolant flow and perpendicular to the direction in which the protrusion protrudes, is 30% or less of the width of the flow path perpendicular direction of the flow path 14 that cools the single semiconductor module 40 at the location where the protrusion is provided. When a plurality of protrusions are provided on one or both of the upstream and downstream sides of a single semiconductor module 40, the sum of the outer diameters of the protrusions provided on the same side in the flow path perpendicular direction is 30% or less of the width of the flow path perpendicular direction of the flow path 14 that cools the single semiconductor module 40 at the location where the protrusion is provided.

[0037] In Figures 8 to 10, the width of the flow path 14 that cools a single semiconductor module 40 in the direction perpendicular to the flow path at the location where the protrusion is provided is indicated as flow path width 22. Figure 9 is a view of the semiconductor module 40 side from inside the flow path 14 in the configuration of Figure 8. In the configuration shown in Figure 9, a single protrusion is provided on both the upstream and downstream sides. Protrusion 16 is provided on the upstream side, and protrusion 17 is provided on the downstream side. The outer diameter of protrusion 16 in the direction perpendicular to the flow path is designated as protrusion outer diameter 23, and the outer diameter of protrusion 17 in the direction perpendicular to the flow path is designated as protrusion outer diameter 24. Protrusion 16 has a recess 16a, and protrusion 17 has a recess 17a. In Figure 8, when the center line of the semiconductor module 40 in the direction perpendicular to the flow path is designated as symmetry line 36, in Figure 9, protrusions 16 and 17 are provided at the end of flow path width 22 on one side of line symmetry 36. When a single semiconductor module 40 is provided, the end of the flow path width 22 becomes a wall surface of the base 11a. When a plurality of semiconductor modules 40 are provided, the end of the flow path width 22 on the side of another adjacent semiconductor module becomes a boundary surface with the flow path that cools the other semiconductor module.

[0038] In the configuration shown in Figure 10, multiple protrusions are provided on the upstream side and a single protrusion is provided on the downstream side. Protrusions 16 and 25 are provided on the upstream side, and protrusion 17 is provided on the downstream side. The outer diameter of protrusion 16 in the direction perpendicular to the flow path is protrusion outer diameter 23, the outer diameter of protrusion 25 in the direction perpendicular to the flow path is protrusion outer diameter 26, and the outer diameter of protrusion 17 in the direction perpendicular to the flow path is protrusion outer diameter 24. Protrusion 16 has a recess 16a, protrusion 25 has a recess 25a, and protrusion 17 has a recess 17a. When the center line of semiconductor module 40 in the direction perpendicular to the flow path is defined as a line of symmetry 36, protrusions 16 and 17 are provided on one side of line of symmetry 36 at one end of flow path width 22, and protrusion 25 is provided on the other side of line of symmetry 36 at the other end of flow path width 22.

[0039] The protrusions also contribute to cooling the semiconductor module. On the other hand, as the outer diameter of the protrusions increases, the flow of refrigerant to the fins 12 is restricted, thereby reducing the cooling performance of the fins 12. In the configuration shown in FIG. 9 , the protrusion outer diameter 23 is equal to or less than 30% of the flow path width 22, and the protrusion outer diameter 24 is equal to or less than 30% of the flow path width 22. In the configuration shown in FIG. 10 , the sum of the protrusion outer diameter 23 and the protrusion outer diameter 26 is equal to or less than 30% of the flow path width 22, and the protrusion outer diameter 24 is equal to or less than 30% of the flow path width 22. This configuration allows the protrusions to function as fins to cool the semiconductor module 40, thereby outweighing the effect of the protrusions impeding the cooling effect of the fins 12. Therefore, the protrusions and the fins 12 can efficiently dissipate heat from the semiconductor module 40 to the refrigerant. The value of 30% was derived through simulation.

[0040] The flow of the refrigerant in the flow path 14 will be described using Figures 11 and 12. In the figures, the flow of the refrigerant is indicated by arrows as refrigerant flow lines 33. At least one protrusion is provided both upstream of the region where the fins 12 are provided and downstream of the region where the fins 12 are provided. In the configuration shown in Figures 11 and 12, one protrusion is provided both upstream of the region where the fins 12 are provided and downstream of the region where the fins 12 are provided. In Figure 11, the protrusions 16 and 17 are provided in positions similar to the positions of the protrusions 16 and 17 shown in Figure 9. In Figure 12, the upstream protrusion 16 and the downstream protrusion 17 are arranged point-symmetrically with respect to the center 33a of the region of the cooler 11 where the fins 12 are provided.

[0041] As shown in FIG. 13 , a region 35a where vortices and stagnation occur is formed downstream of the protrusion 16. As shown in FIG. 14 , a region 35b where vortices and stagnation occur is formed downstream of the protrusion 17. The regions 35a and 35b where vortices and stagnation occur are regions where the refrigerant does not flow smoothly. In the arrangement of the protrusions 16 and 17 shown in FIG. 11 , the protrusions 16 and 17, which act as refrigerant barriers in the direction of refrigerant flow, are aligned along the wall surface of the base 11a. This reduces the flow rate of the refrigerant in the portion of the flow path 14 sandwiched between the protrusions 16 and 17, creating a region 34 where the refrigerant stagnates. The region 34 where the refrigerant stagnates is the region surrounded by a dashed line. Because the refrigerant does not flow smoothly in the region 34 where the refrigerant stagnates, heat dissipation from the semiconductor module 40 in the region 34 where the refrigerant stagnates is suppressed.

[0042] 12, the upstream protrusions 16 and the downstream protrusions 17 are arranged point-symmetrically with respect to the center 33a of the area of ​​the cooler 11 provided with the fins 12, so that the protrusions that act as a barrier to the refrigerant in the direction of flow are not lined up along the wall surface of the base 11a, and areas where the refrigerant stagnates 34 are suppressed, thereby enabling efficient dissipation of heat from the semiconductor module 40 to the refrigerant. When the protrusions are arranged point-symmetrically, the greater the distance between the protrusions, the greater the effect of improving the cooling performance of the semiconductor module 40.

[0043] When the fluid resistance in the area where the fins 12 are arranged is high, such as when the pin fins are densely arranged, the flow rate of the refrigerant in the area where the fins 12 are arranged slows down and the refrigerant flows uniformly. Therefore, the refrigerant spreads evenly in the area where the fins 12 are arranged. When the protrusions 16, 17 are arranged as shown in Figure 12, there is almost no stagnation area 34 of the refrigerant downstream of the protrusions 16, so the flow of the refrigerant in the area where the fins 12 are arranged can be made more uniform.

[0044] In this embodiment, the cooler 11 has a plurality of protrusions, and at least one of the protrusions has a circular cross-sectional shape and at least one has an elongated hole cross-sectional shape in a direction perpendicular to the direction in which the protrusions protrude. In the configuration shown in Figures 11 and 12, the cooler 11 has two protrusions 16 and 17, and the cross-sectional shape of the protrusion 16 is circular and the cross-sectional shape of the protrusion 17 is elongated hole cross-sectional shape. By making at least one of the protrusions elongated hole cross-sectional shape, even if there is variation in the spacing between the positioning pins 45 of the semiconductor module 40, the semiconductor module 40 does not lift up from the base 11a, and the dimensional tolerance of the arrangement of the positioning pins 45 can be absorbed, thereby ensuring reliable engagement between the positioning pins 45 and the recesses 16a and 17a of the protrusions 16 and 17.

[0045] In this embodiment, the protrusions 16 having a circular cross section are arranged upstream, and the protrusions 17 having an elongated cross section are arranged downstream. Comparing the region 35a where vortices and stagnation occur due to the protrusions 16 shown in FIG. 13 with the region 35b where vortices and stagnation occur due to the protrusions 17 shown in FIG. 14 , the region 35b where vortices and stagnation occur has a longer section in the refrigerant flow direction 20 where vortices and stagnation exist, resulting in a larger stagnation region where the refrigerant flow velocity is slow. As shown in FIGS. 11 and 12 , the protrusions 16 having a circular cross section are arranged upstream, and the protrusions 17 having an elongated cross section are arranged downstream, thereby reducing the region where the refrigerant flow velocity is slow in the region where the fins 12 are arranged, thereby improving the cooling performance of the semiconductor module 40.

[0046] As described above, in the power conversion device 1 according to embodiment 2, the protrusions extend in a direction perpendicular to the direction of refrigerant flow, and when a single protrusion is provided on either or both the upstream and downstream sides of a single semiconductor module 40, the outer diameter of the protrusion in the direction perpendicular to the flow path is 30% or less of the width of the flow path 14 in the direction perpendicular to the flow path, and when a plurality of protrusions are provided on either or both the upstream and downstream sides of a single semiconductor module 40, the sum of the outer diameters of the protrusions in the direction perpendicular to the flow path is 30% or less of the width of the flow path 14 in the direction perpendicular to the flow path. Therefore, the effect of the protrusions functioning as fins to cool the semiconductor module 40 is greater than the effect of the protrusions interfering with the cooling effect of the fins 12, and therefore the protrusions and fins 12 can efficiently dissipate heat from the semiconductor module 40 to the refrigerant.

[0047] When at least one protrusion is provided both upstream of the area where the fins 12 are provided and downstream of the area where the fins 12 are provided, and the upstream protrusion 16 and the downstream protrusion 17 are arranged point-symmetrically with respect to the center 33a of the area of ​​the cooler 11 where the fins 12 are provided, the protrusions that act as barriers to the refrigerant in the direction in which the refrigerant flows are not lined up along the wall surface of the base 11a, and areas where stagnation of the refrigerant occurs are suppressed, so that heat from the semiconductor module 40 can be efficiently dissipated into the refrigerant.

[0048] If the cooler 11 has multiple protrusions, and the cross-sectional shape of the protrusions in a direction perpendicular to the direction in which the protrusions protrude is such that at least one is circular and at least one is oblong hole shaped, even if there is variation in the spacing of the positioning pins 45 of the semiconductor module 40, the dimensional tolerance of the arrangement of the positioning pins 45 can be absorbed by the oblong hole shape, so that the positioning pins 45 can be reliably engaged with the recesses 16a, 17a of the protrusions 16, 17.

[0049] When the protrusion 16 having a circular cross-sectional shape is arranged on the upstream side and the protrusion 17 having an elongated hole cross-sectional shape is arranged on the downstream side, the area where the fin 12 is arranged and the refrigerant flow rate is slow becomes smaller, thereby improving the cooling performance of the semiconductor module 40.

[0050] Third Embodiment A power conversion device 1 according to a third embodiment will now be described. Fig. 15 is a cross-sectional view showing an outline of the power conversion device 1 according to the third embodiment, taken at a position equivalent to that of Fig. 2, Fig. 16 is a cross-sectional view showing an outline of another power conversion device 1 according to the third embodiment, taken at a position equivalent to that of Fig. 15, and Fig. 17 is a cross-sectional view showing an outline of another cooler 11 of the other power conversion device 1, taken at a position equivalent to that of Fig. 15. The power conversion device 1 according to the third embodiment has a configuration in which the length of the protrusions is specified.

[0051] In this embodiment, the distance between the end of the protrusion and the bottom wall of the cooler 11 facing the end of the protrusion is equal to or greater than the distance between the end of the fin 12 and the bottom wall of the cooler 11 facing the end of the fin 12. In the configuration shown in Fig. 15, the distance between the end of the protrusion 16 and the facing surface 15 of the lid 13, which is the bottom wall of the cooler 11 facing the end of the protrusion 16, is the protrusion interval 30, the distance between the end of the protrusion 17 and the facing surface 15 of the lid 13, which is the bottom wall of the cooler 11 facing the end of the protrusion 17, is the protrusion interval 31, and the distance between the end of the fin 12 and the facing surface 15 of the lid 13, which is the bottom wall of the cooler 11 facing the end of the fin 12, is the fin interval 32. The protrusion intervals 30 and 31 are equal to or greater than the fin interval 32.

[0052] By configuring in this manner, the reduction in the flow rate of the coolant caused by the protrusions 16, 17 and the reduction in vortices and stagnation of the coolant are reduced, thereby suppressing the reduction in the cooling performance of the semiconductor module 40 in the area where the fins 12 are provided.

[0053] The configuration shown in FIG. 16 differs from the configuration shown in FIG. 15 in the locations where the refrigerant flows into and out of the flow paths 14 of the cooler 11. The locations where the refrigerant flows in and out are provided in the lid 13. In FIG. 16, a water jacket 29 is provided at the locations where the refrigerant flows in and out in FIG. 15. Furthermore, the positions of the opposing surfaces 15 on the lid 13 are different between the locations where the protrusions 16 and 17 face each other and the locations where the fins 12 face each other. Because the positions of the opposing surfaces 15 are different between the locations where the protrusions 16 and 17 face each other and the locations where the fins 12 face each other, even if the protrusion spacing 30, 31 is much larger than the fin spacing 32, the protrusion spacing 30, 31 is equal to or larger than the fin spacing 32, and therefore does not affect the flow of refrigerant in the area where the fins 12 are provided. Therefore, a configuration in which the protrusion spacing 30, 31 is much larger than the fin spacing 32 is acceptable.

[0054] In this embodiment, the length of the protrusions in the direction in which they protrude is 50% or more of the length of the fins 12 in the direction in which they protrude. In the configuration shown in Fig. 15, the length of the protrusions 16, 17 in the direction in which they protrude is 50% or more of the length of the fins 12 in the direction in which they protrude, and the length of the protrusions 16, 17 is about 80% of the length of the fins 12.

[0055] With this configuration, the contact area of ​​the protrusions 16, 17 with the refrigerant is sufficiently large, allowing the protrusions 16, 17 to contribute as cooling fins to cooling the semiconductor module 40. Furthermore, since increasing the length of the protrusions 16, 17 has little effect on reducing the flow rate of the refrigerant flowing toward the region where the fins 12 are provided, the cooling performance of the semiconductor module 40 can be improved even if the length of the protrusions 16, 17 is increased. The value of 50% was derived through simulation.

[0056] In this embodiment, at least a portion of the end of the protrusion is chamfered or has an R-shape. In the configuration shown in Fig. 17, the ends of protrusions 16, 17 have an R-shape. The R-shaped portions of the ends of protrusions 16, 17 are rounded corners 28. This configuration makes it difficult for eddies and stagnation of the coolant to occur around the tips of protrusions 16, 17, thereby reducing the effect of a decrease in the flow rate of the coolant flowing toward the region where fins 12 are provided, thereby improving the cooling performance of semiconductor module 40.

[0057] As described above, in the power conversion device 1 according to embodiment 3, the distance between the end of the protrusion and the bottom wall of the cooler 11 facing the end of the protrusion is greater than the distance between the end of the fin 12 and the bottom wall of the cooler 11 facing the end of the fin 12, so the reduction in the flow rate of the refrigerant caused by the protrusions 16 and 17, and the vortices and stagnation of the refrigerant are reduced, thereby suppressing the reduction in the cooling performance of the semiconductor module 40 in the area where the fin 12 is provided.

[0058] When the length of the protrusions in the protruding direction is 50% or more of the length of the fins 12 in the protruding direction, the contact area of ​​the protrusions 16, 17 with the refrigerant becomes large enough so that the protrusions 16, 17 can function as cooling fins to contribute to cooling the semiconductor module 40. Furthermore, extending the length of the protrusions 16, 17 has little effect on reducing the flow rate of the refrigerant flowing into the region where the fins 12 are provided, so the cooling performance of the semiconductor module 40 can be improved even if the length of the protrusions 16, 17 is extended.

[0059] When at least a portion of the end of the protrusion is chamfered or has an R-shape, vortices and stagnation of the refrigerant are less likely to occur around the tips of the protrusions 16 and 17, which reduces the effect of reducing the flow rate of the refrigerant flowing into the area where the fins 12 are provided, thereby improving the cooling performance of the semiconductor module 40.

[0060] Fourth Embodiment A power conversion device 1 according to a fourth embodiment will now be described. Fig. 18 is a plan view showing an outline of the power conversion device 1 according to the fourth embodiment, showing only the portion corresponding to the flow path 14 that cools the two semiconductor modules 40, 47, and Fig. 19 is a plan view explaining the flow of refrigerant in the flow path 14 of the power conversion device 1, looking at the semiconductor modules 40, 47 from the inside of the flow path 14. The power conversion device 1 according to the fourth embodiment is configured to include a plurality of semiconductor modules.

[0061] In this embodiment, the power conversion device 1 includes a plurality of semiconductor modules, which are arranged side by side in a direction perpendicular to the direction of coolant flow. In the configuration shown in Fig. 18, the power conversion device 1 includes two semiconductor modules 40, 47. The two semiconductor modules 40, 47 are arranged side by side in a direction perpendicular to the direction 20 of coolant flow. With this configuration, all of the semiconductor modules are cooled by a coolant that has not yet cooled the semiconductor module, thereby improving the cooling performance of each of the semiconductor modules.

[0062] Furthermore, similar to the configuration shown in the second embodiment, the protrusions 16, 17 are provided on both the portion of the cooler 11 upstream of each of the semiconductor modules 40, 47 and the portion of the cooler 11 downstream of each of the semiconductor modules 40, 47. With this configuration, even when a plurality of semiconductor modules are provided, the protrusions are provided at positions away from the center of each of the semiconductor modules 40, 47, so that the semiconductor modules 40, 47 can be accurately positioned with respect to the cooler 11 without impeding the heat dissipation performance of the semiconductor modules 40, 47.

[0063] Furthermore, as shown in Fig. 19, the upstream protrusions 16 and the downstream protrusions 17 are arranged point-symmetrically with respect to the center 33a of the area of ​​the cooler 11 provided with the fins 12. With this configuration, the protrusions that act as a barrier to the refrigerant are not lined up along the wall surface of the base 11a in the direction in which the refrigerant flows, and the refrigerant flows regularly along the refrigerant flow lines 33. This reduces the influence of stagnation that occurs downstream of the protrusions and a decrease in flow rate on the side of the protrusions, thereby reducing the impact of a decrease in cooling performance, and thus allows each of the multiple semiconductor modules to be cooled effectively.

[0064] Furthermore, although various exemplary embodiments and examples are described in this disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless modifications not illustrated are contemplated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0065] 1 Power conversion device, 11 Cooler, 11a Base, 11a1 Cooling surface, 12 Fin, 13 Lid, 14 Flow path, 15 Opposing surface, 16, 17, 25 Protrusion, 16a, 17a, 25a Recess, 18 Fin-fin distance, 19 Protrusion-fin distance, 20 Coolant flow direction, 21 Projection line, 22 Flow path width, 23, 24, 26 Protrusion outer diameter, 27 Element projection area, 27a Diffusion area, 28 Corner R portion, 29 Water jacket, 30, 31 Protrusion spacing, 32 Fin spacing, 33 Coolant flow line, 33a Center, 34 Coolant stagnation area, 35a, 35b Area where vortex and stagnation occur, 36 Symmetry line, 37 45 degree diffusion line, 40 Semiconductor module, 40a Bottom surface, 41 Molded resin, 42 Semiconductor element, 43 heat spreader, 44 bonding surface, 45 positioning pin, 46 connection terminal, 47 semiconductor module, 49 insulating member, 50 bonding member, 51 heat spreader

Claims

1. A power conversion device comprising: one or more semiconductor modules each having one or more semiconductor elements; and a cooler having a flow path inside which a refrigerant flows and which cools the semiconductor module; wherein the semiconductor module and the cooler are thermally connected via a bonding member; the cooler has one or more protrusions protruding into the flow path from a side portion of the flow path on the semiconductor module side; the protrusions have a recess on the opposite side to the flow path that opens towards the semiconductor module; the semiconductor module has a positioning pin that protrudes towards the cooler and is inserted into the recess; and the semiconductor module is positioned relative to the cooler by the positioning pin.

2. A power conversion device as claimed in claim 1, wherein the coolant flows through the flow path from one side, that is, the upstream side, to the other side, that is, the downstream side, relative to the semiconductor module, and wherein one or more of the protrusions are provided on one or both of the part of the cooler on the upstream side of the semiconductor module and the part of the cooler on the downstream side of the semiconductor module.

3. A power conversion device according to claim 1 or 2, wherein the cooler has a plurality of fins that protrude into the flow path from a portion to which the semiconductor module is thermally connected, and the protrusion is provided at a distance from the plurality of fins.

4. The power conversion device according to claim 3, wherein the distance between the protrusion and the fin adjacent to the protrusion is greater than the distance between two adjacent fins.

5. A power conversion device according to claim 3 or 4, wherein the semiconductor element is provided facing the flow path, and the protrusion is not provided in an element projection area, which is the area of ​​the flow path where the semiconductor element is projected onto the flow path.

6. A power conversion device according to claim 3 or 4, wherein the semiconductor element is disposed opposite the flow path, and the protrusion is not provided in an element projection area, which is the area of ​​the flow path where the semiconductor element is projected onto the flow path, and in an area obtained by adding the distance from the semiconductor element to the side of the flow path on which the semiconductor element is located to the periphery of the element projection area.

7. The power conversion device according to claim 2, wherein the protrusion extends in a direction perpendicular to the direction of flow of the refrigerant, and when a single protrusion is provided on either or both of the upstream side and the downstream side for a single semiconductor module, the outer diameter of the protrusion in a flow path perpendicular direction, which is perpendicular to the direction of flow of the refrigerant and perpendicular to the direction in which the protrusion protrudes, is 30% or less of the width of the flow path perpendicular direction of the flow path that cools the single semiconductor module at the location where the protrusion is provided, and when a plurality of the protrusions are provided on either or both of the upstream side and the downstream side for a single semiconductor module, the sum of the outer diameters of the protrusions provided on the same side in the flow path perpendicular direction is 30% or less of the width of the flow path perpendicular direction of the flow path that cools the single semiconductor module at the location where the protrusion is provided.

8. The power conversion device according to claim 2, wherein the cooler has a plurality of fins protruding into the flow path from the portion to which the semiconductor module is thermally connected, and at least one protrusion is provided both upstream of the area where the fins are provided and downstream of the area where the fins are provided, and the upstream protrusion and the downstream protrusion are arranged point-symmetrically with respect to the center of the area of ​​the cooler where the fins are provided.

9. A power conversion device according to any one of claims 1 to 8, wherein the cooler has a plurality of the protrusions, and at least one of the cross-sectional shapes of the protrusions in a direction perpendicular to the direction in which the protrusions protrude is circular and at least one of the cross-sectional shapes is an oblong hole.

10. A power conversion device described in any one of claims 3 to 6, wherein the distance between the end of the protrusion and the bottom wall of the cooler facing the end of the protrusion is equal to or greater than the distance between the end of the fin and the bottom wall of the cooler facing the end of the fin.

11. A power conversion device according to any one of claims 3 to 6, wherein the length of the protrusion in the direction in which the protrusion protrudes is 50% or more of the length of the fin in the direction in which the fin protrudes.

12. The power conversion device according to any one of claims 1 to 11, wherein at least a portion of the end of the protrusion is chamfered or has an R-shape.

13. A power conversion device according to any one of claims 1 to 12, comprising a plurality of the semiconductor modules, the plurality of semiconductor modules being arranged side by side in a direction perpendicular to the direction of flow of the refrigerant.

14. A power conversion device according to any one of claims 1 to 13, wherein the cooler has a cooling surface, and the flat surface of the semiconductor module facing the cooler is thermally connected to the cooling surface via the joining member.

15. A power conversion device as claimed in any one of claims 1 to 14, wherein the cooler is formed from a main body portion having an opening on the side opposite to the side on which the semiconductor module is provided, and a lid covering the opening of the main body portion.

16. The power conversion device according to claim 2, wherein the cooler has a plurality of the protrusions, at least one of the cross-sectional shapes of the protrusions in a direction perpendicular to the direction in which the protrusions protrude is circular and at least one of the cross-sectional shapes is elongated hole-shaped, and the protrusion having a circular cross-sectional shape is arranged on the upstream side, and the protrusion having an elongated hole-shaped cross-sectional shape is arranged on the downstream side.

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