Cooler base, cooler and semiconductor device

Abstract

A cooler (1A) comprises: a case (10A) that has therein a bottom surface portion of a flow path through which coolant flows, a supply groove which is provided at an upstream end of the bottom surface portion, which is recessed more than the upstream end, and which supplies coolant flowing thereinside to the flow path, and a discharge groove which is provided at a downstream end of the bottom surface portion, which is recessed more than the downstream end, inside which coolant having flowed in from the flow path flows, and which discharges the coolant; and a base that is provided with a heat-radiating body on one surface side thereof, that has another surface which faces the bottom surface portion of the flow path, that covers the bottom surface portion, the supply groove, and the discharge groove, and that has a plurality of fins (30) which are arranged on the other surface side.

Description

Cooler and semiconductor device

[0001] The present disclosure relates to a cooler and a semiconductor device.

[0002] Some coolers use a refrigerant to cool a heat generating element, such as a semiconductor element.

[0003] For example, Patent Document 1 discloses a cooler that includes a box-shaped case that is open on the top side, and a base plate that has a semiconductor element on one side and a plurality of fins on the other side and closes the opening of the case with the other side facing the internal space of the case. This cooler dissipates heat transferred from the semiconductor element to the plurality of fins into the coolant by flowing a coolant through the internal space of the case.

[0004] Japanese Patent Application Laid-Open No. 2022-137411

[0005] The inside of the case of the cooler described in Patent Document 1 is provided with a bottom surface portion facing the base plate and forming a flow path, a supply groove adjacent to the upstream end of the bottom surface portion for supplying the refrigerant to the flow path, and a discharge groove adjacent to the downstream end of the bottom surface portion for discharging the refrigerant from the flow path. As a result, in this cooler, the refrigerant flows in a spread manner throughout the entire flow path, increasing cooling efficiency.

[0006] Furthermore, in the cooler described in Patent Document 1, multiple fins are provided on the other surface of the base plate in an area facing the bottom portion of the flow path. To enhance cooling efficiency, the area where these fins are provided overlaps with the area where the semiconductor elements are provided on one surface of the base plate when viewed perpendicularly to the other surface of the base plate. As a result, the bottom portion of the flow path may be larger than the area where the semiconductor elements are provided on the other surface of the base plate. This may result in the cooler itself being too large relative to the semiconductor elements to be cooled.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a cooler and a semiconductor device that have high cooling efficiency and are miniaturized relative to the heat-generating body to be cooled.

[0008] To achieve the above object, the present disclosure provides a cooler comprising: a case having a rectangular shape with two opposing sides facing upstream and downstream, the case having a bottom surface of a flow path through which a refrigerant flows; a supply groove provided at an upstream end of the bottom surface, recessed from the upstream end to supply the refrigerant flowing inside to the flow path; and a discharge groove provided at a downstream end of the bottom surface, recessed from the downstream end to discharge the refrigerant flowing from the flow path; and a base having a heating element on one side and a second side facing the bottom surface of the flow path, covering the bottom surface, the supply groove, and the discharge groove, and further having a plurality of fins arranged on the second side. The plurality of fins are provided in a flow path region of the second side of the base that faces at least the bottom surface, and that overlaps with the region of the one side of the base where the heating element is provided when viewed from a direction perpendicular to the second side. The fins are arranged in the direction of extension of the flow path from the upstream end to the downstream end of the bottom surface, and are arranged in the width direction of the flow path, which is perpendicular to the direction of extension of the flow path, when viewed from a direction perpendicular to the other surface. The cooler is set on the bottom surface, and when the distance from a reference line extending in the width direction to the upstream end of the bottom surface is D1, the distance from the reference line to the upstream end of a first fin arranged most upstream among the fins is D2, and the distance from the end of the width direction of the flow path to a second fin arranged most downstream among the fins is D3, the relationship D1 - D2 < D3 is satisfied. Alternatively, when the distance from the reference line to the downstream end of the bottom surface is D4, and the distance from the reference line to the downstream end of a third fin arranged most downstream among the fins is D5, the relationship D4 - D5 < D3 is satisfied.

[0009] According to the configuration of the present disclosure, the cooler satisfies the above-mentioned relationship D1-D2<D3 or D4-D5<D3. Therefore, in the cooler, the flow path area where the fins are arranged can be made as small as possible at the bottom of the flow path. As a result, the cooler has high cooling efficiency and is small compared to the heat-generating body to be cooled.

[0010] a perspective view of a cooler according to a first embodiment of the present disclosure; a component configuration diagram of a cooler according to a first embodiment of the present disclosure; a cross-sectional view taken along the III-III cutting line shown in FIG. 1; a conceptual diagram showing the shape of a groove formed in a case included in a cooler according to a first embodiment of the present disclosure; a cross-sectional view taken along the V-V cutting line shown in FIG. 1; a perspective view of a base plate included in a cooler according to a first embodiment of the present disclosure; an enlarged view of region VII shown in FIG. 6; a left side view of a base plate included in a cooler according to a first embodiment of the present disclosure; a bottom view of region X shown in FIG. 9; a top view showing the positional relationship between flat surface portions, grooves, and fins provided in a case included in a cooler according to a second embodiment of the present disclosure; a cross-sectional view of a first modified example of a groove formed in a case included in the cooler according to the first embodiment of the present disclosure; a cross-sectional view of a second modified example of a groove formed in a case included in the cooler according to the first embodiment of the present disclosure; a cross-sectional view of a fourth modified example of a groove formed in a case included in the cooler according to the first embodiment of the present disclosure; a top view showing the positional relationship between an end of a flat surface portion of a case included in the cooler according to the first embodiment of the present disclosure and a modified example of a fin;

[0011] A cooler and a semiconductor device according to embodiments of the present disclosure will be described in detail below with reference to the drawings. In the drawings, identical or equivalent parts are designated by the same reference numerals. In the illustrated Cartesian coordinate system XYZ, when the longitudinal direction of the rectangular base plate of the cooler is oriented left-right and the lateral direction is oriented front-to-rear, the left-to-right direction is the X-axis, the front-to-rear direction is the Y-axis, and the direction perpendicular to the X-axis and Y-axis is the Z-axis. This coordinate system will be referenced as appropriate below.

[0012] (Embodiment 1) A cooler according to embodiment 1 is a device that cools a heat-generating body by using a refrigerant to cool a plurality of fins provided on a base plate on which the heat-generating body to be cooled is mounted. The fins are arranged in specific positions, thereby miniaturizing the cooler while improving cooling efficiency. This cooler will be described in detail below, taking as an example a case in which the heat-generating body is a power module, which is a type of semiconductor device. First, the overall configuration of the cooler will be described with reference to Figures 1 to 8.

[0013] FIG. 1 is a perspective view of a cooler 1A according to the first embodiment. FIG. 2 is a diagram showing the components of the cooler 1A. FIG. 3 is a cross-sectional view taken along the III-III cutting line shown in FIG. 1. FIG. 4 is a conceptual diagram showing the shapes of grooves 12 and 13 formed in a case included in the cooler 1A. FIG. 5 is a cross-sectional view taken along the V-V cutting line shown in FIG. 1. FIG. 6 is a perspective view of a base plate 20A included in the cooler 1A. FIG. 7 is an enlarged view of region VII shown in FIG. 6. FIG. 8 is a left side view of the base plate 20A.

[0014] For ease of understanding, Fig. 2 also illustrates the fins 30 on the underside of the base plate 20A, i.e., on the -Z plane side. Fig. 3 emphasizes the size of the fins 30. Figs. 6 to 8 show views in which the -Z plane of the base plate 20A faces upward.

[0015] As shown in FIG. 1, the cooler 1A includes a case 10A through which a refrigerant flows, and a base plate 20A attached to the case 10A, on which a plurality of power modules 2 to be cooled are mounted, and which cools the power modules 2.

[0016] As shown in Figure 2, the case 10A has the outer shape of a rectangular parallelepiped, more specifically, a thick rectangular plate. The case 10A is positioned with its plate surface facing up and down. A recess 11 is formed in the center of the top surface of the case 10A. The recess 11 has a rectangular shape with its longitudinal direction facing left and right in a top view. The recess 11 has parallel grooves 12 and 13 spaced apart in the front-to-rear direction, and a flat surface portion 14 between the grooves 12 and 13.

[0017] The groove 12 is also called a header, and when a refrigerant is supplied, it distributes the refrigerant to the entire flow path formed by the flat surface portion 14 and supplies the refrigerant to the flow path. Explaining the configuration in detail, the groove 12 extends in the left-right direction, i.e., in the X direction, along the rear end of the flat surface portion 14 to supply the refrigerant to the entire flat surface portion 14. The length of the groove 12 is the same as the length of the flat surface portion 14 in the X direction. A through-hole 121 (shown in FIG. 3) that penetrates the case 10A is formed in the inner wall of the -X end of the groove 12, and a pipe fitting 122 (shown in FIG. 2) is fitted into the through-hole 121.

[0018] The pipe fitting 122 is connected to a pipe extending from an external device (not shown). The pipe fitting 122 receives a refrigerant, such as water or ethylene glycol, from the external device and supplies the refrigerant to the groove 12. More specifically, the pipe fitting 122 has a through hole 121 (shown in FIG. 3 ) formed closer to the bottom than the opening of the groove 12, allowing the refrigerant to flow into the bottom side of the groove 12.

[0019] 3, the groove 12 is larger than the pipe joint 122 in a cross-sectional view. As a result, the groove 12 reduces the pressure loss when the refrigerant flows in from the pipe joint 122.

[0020] 3 and 4, the groove 12 has a shape that combines a rectangle and a circle in a cross-sectional view. Specifically, as shown in FIG. 3, the groove 12 has a shape in a YZ cross-sectional view in which a rectangle whose longitudinal direction is oriented in the Z direction and whose lateral direction is oriented in the Y direction overlaps with a circle having a diameter D6 that is smaller than the longitudinal length L1 of the rectangle and larger than the lateral length L2 of the rectangle. Furthermore, in a YZ cross-sectional view, the groove 12 has a shape in which the circle is tangent to the side extending in the longitudinal direction of the rectangle, i.e., the -Y side, and also to the side extending in the lateral direction of the rectangle, i.e., the -Z side. The groove 12 extends straight in the X direction while maintaining this cross-sectional shape.

[0021] By having such a shape, the circular portion of the groove 12 in the YZ cross section allows the refrigerant supplied from the pipe joint 122 to smoothly flow into the +X side of the groove 12, i.e., into the depths thereof.

[0022] Furthermore, the rectangular portion of the groove 12 in the YZ cross section directs the refrigerant that has flowed into the bottom of the groove 12 via the pipe fitting 122 toward the opening of the groove 12 in the longitudinal direction of the rectangle. Specifically, in the groove 12, the length L1 of the longitudinal direction of the rectangle in the YZ cross section is greater than the length L2 of the lateral direction. Furthermore, the -Y side and +Y side extending in the longitudinal direction of the rectangle in the YZ cross section extend straight in the Z direction. As a result, when the refrigerant flows along the -Y side and +Y side of the groove 12, it is easily equalized in the +X direction of the groove 12.

[0023] Furthermore, groove 12 has a circular portion near the bottom in a YZ cross section, so that the width of the opening in the YZ cross section is smaller in the Y direction than the width of the circular portion near the bottom. As a result, when the refrigerant flows from the bottom to the opening in groove 12, a large resistance is applied to the refrigerant. This makes it easier for the refrigerant to spread throughout the entire X direction within groove 12, and makes it less likely to be unevenly distributed in the X direction.

[0024] On the other hand, a flat surface portion 14 is provided on the +Y side of the opening of the groove 12, as shown in FIG.

[0025] The flat surface portion 14 functions as the bottom portion of a flow path through which a refrigerant flows to cool the multiple fins 30 (described later). The fins 30 shown in FIG. 2 are arranged in an elongated rectangular region A1 of the base plate 20A, which is the same shape and size as the multiple power modules 2, in order to cool the multiple power modules 2 arranged in an elongated rectangular shape. To cool the fins 30, the flat surface portion 14 is formed in an elongated rectangular shape of the same shape and size as the region A1. The longitudinal direction of the flat surface portion 14 is oriented in the X direction. Furthermore, the openings of the grooves 12 are adjacent to the Y direction, which is the short direction of the flat surface portion 14. As a result, the refrigerant flows from the grooves 12 into the -Y end of the flat surface portion 14 where the grooves 12 are located. This allows the flat surface portion 14 to function as a flow path with the -Y end as the upstream end.

[0026] The flat surface portion 14 may have any shape as long as it is rectangular in accordance with the shape of the arrangement to be cooled, for example, a square. Here, a rectangle means a quadrangle with all four corners being equal.

[0027] The flat surface portion 14 is formed flat to allow the refrigerant to flow smoothly. The flat surface portion 14 is made of a material with high thermal conductivity to come into contact with the fins 30 and exchange heat with them. When the refrigerant flows through the flat surface portion 14, the flat surface portion 14 releases heat transferred from the fins 30 to the refrigerant. This allows the flat surface portion 14 to cool the fins 30 with high efficiency.

[0028] Furthermore, as shown in FIG. 3 , the base plate 20A is provided on the case 10A, so that the flat surface portion 14 faces the base plate 20A. As a result, the flat surface portion 14 forms a flow path for the refrigerant between the flat surface portion 14 and the base plate 20A. The size of the gap between the flat surface portion 14 and the base plate 20A, i.e., the height H1 of the flow path, is smaller than the depth of the groove 12. That is, the height H1 of the flow path is smaller than the length L1 of the rectangular groove 12 in the longitudinal direction when viewed in the YZ cross section. The height H1 of the flow path is also smaller than the width of the groove 12. That is, the height H1 of the flow path is smaller than the length L2 of the rectangular groove 12 in the lateral direction when viewed in the YZ cross section. This increases the resistance of the refrigerant when it flows from the groove 12 into the flow path. As a result, the refrigerant is easily distributed throughout the flow path when it flows in. This results in a uniform flow rate of the refrigerant in the flow path. Furthermore, the small height H1 in the flow path increases the flow rate of the refrigerant. As a result, the cooling efficiency of the fins 30 is high in the flow path.

[0029] On the other hand, the groove 13 opens at the downstream end of the flow path, i.e., the +Y end of the flat surface portion 14. As a result, when the refrigerant flows through the flat surface portion 14, the refrigerant flows out into the groove 13.

[0030] Groove 13 is a component also called a header, and collects the refrigerant flowing in from flat surface portion 14 and discharges it to the outside of case 10A. To explain the configuration in detail, groove 13 opens on the +Y side of flat surface portion 14 to collect the refrigerant from the flow path formed by flat surface portion 14. As shown in FIG. 2 , the +Y end of flat surface portion 14 extends straight in the X direction, and thus groove 13 also extends in the X direction. Furthermore, the X-direction length of groove 13 is the same as the X-direction length of flat surface portion 14. As a result, groove 13 collects the refrigerant from the entire flow path formed by flat surface portion 14.

[0031] 3, groove 13 has a shape that is symmetrical in the front-to-back direction to groove 12 described above in a cross-sectional view. Specifically, the shape of groove 13 in a YZ cross-sectional view is symmetrical with the shape of groove 12 in a YZ cross-sectional view about a center line L3 of case 10A that is parallel to the Z axis and passes through the center between grooves 12 and 13. As a result, the action of groove 13 on the refrigerant is similar to that of groove 12. Therefore, a description of the shape and size of groove 13 and a description of the action of groove 13 on the refrigerant will be omitted.

[0032] A through-hole 131 that penetrates the case 10A is formed in the inner wall of the +X end of the groove 13 to discharge the refrigerant to the outside. A pipe fitting 132 shown in FIG. 2 is fitted into the through-hole 131. The pipe fitting 132 is connected to a pipe extending from an external device (not shown). As a result, the refrigerant collected in the groove 13 passes through the pipe fitting 132 and is returned to the external device.

[0033] Grooves 12 and 13 having the above-described configuration and flat surface portion 14 are formed in recess 11 of case 10A. A refrigerant flows through grooves 12 and 13 and flat surface portion 14. To confine the refrigerant within recess 11, recess 11 is covered with base plate 20A, as shown in Figures 2 and 3 .

[0034] A plurality of power modules 2 to be cooled are arranged in a row on one surface of the base plate 20A, i.e., the +Z surface. More specifically, six power modules 2 are arranged in a row in the X direction on the +Z surface of the base plate 20A.

[0035] The power module 2 is a component that combines power semiconductor elements that control and convert electric power. Although not shown, the power module 2 is mounted on the +Z surface of the base plate 20A and is connected by electric wires to components arranged in the Y direction, such as a capacitor.

[0036] The base plate 20A is made of a metal with high thermal conductivity to facilitate the transfer of heat generated when the power modules 2 are in operation. As a result, the base plate 20A transfers heat from the power modules 2 mounted on the +Z surface to the −Z surface.

[0037] Furthermore, as shown in FIGS. 3 and 5, a plurality of fins 30 are provided on the −Z surface of the base plate 20A in order to dissipate heat from the power module 2.

[0038] Each fin 30 is formed from the same material as the base plate 20A. This provides each fin 30 with high thermal conductivity, similar to the base plate 20A. As a result, heat from the power module 2 is easily transferred to each fin 30. As shown in FIGS. 6 and 7 , each fin 30 is formed in the shape of a regular hexagonal prism, with the prism axis extending in the −Z direction. The height of each fin 30 is the same as the height H1 of the flow path described above. It is not necessary for all fins 30 to have the same height H1 as the flow path; it is sufficient that the majority of the fins 30 have the same height H1. These fins 30 are provided in an area A1 of the base plate 20A shown in FIG. 6 , which faces the flat surface portion 14 that forms the flow path described above when the recess 11 is covered by the base plate 20A.

[0039] On the other hand, the base plate 20A is formed in a rectangular shape larger than the rectangular shape of the recess 11 in a top view, as shown in FIG. 2, in order to cover the recess 11. Specifically, the base plate 20A has the same short-side length as the rectangular shape of the case 10A in a top view, but is slightly shorter in the long-side length. As shown in FIG. 1, the base plate 20A is superimposed on the case 10A from the +Z side. Furthermore, the base plate 20A is joined to the +Z face of the case 10A. For example, the base plate 20A is joined to the case 10A by welding or mechanically joining to the case 10A with bolts, screws, or the like. This allows the base plate 20A to cover the recess 11 of the case 10A and prevent refrigerant leakage.

[0040] 8, the thickness T1 of the base plate 20A is greater than the length of the fins 30, i.e., the height H1 of the flow path described above. Heat may be applied to the base plate 20A, for example, by soldering, when the power module 2 is mounted. By having the thickness T1 as described above, the base plate 20A is prevented from warping during manufacturing.

[0041] The outer peripheral portion of the -Z surface of the base plate 20A, which is joined to the case 10A, is flattened, for example, by cutting, to improve joinder strength. As a result, a step 21 is formed between the area A1 where the fins 30 are arranged and the other areas. The step 21 surrounds the area A1 where the fins 30 are arranged. With this configuration, the area A1 where the fins 30 are arranged is thicker than the other areas of the base plate 20A, resulting in increased rigidity.

[0042] 3 and 5, the base plate 20A faces the flat surface portion 14 of the case 10A, and forms the above-mentioned flow path between the base plate 20A and the flat surface portion 14. Furthermore, the base plate 20A has the above-mentioned multiple fins 30 arranged in the flow path, and when a refrigerant flows through the flow path, the refrigerant exchanges heat with the fins 30. As a result, the base plate 20A releases heat transferred from the power module 2 from the fins 30 to the refrigerant, thereby cooling the power module 2.

[0043] In order to transfer heat from the power modules 2 with high efficiency, the above-mentioned multiple fins 30 are arranged in an area A1 on the +Z surface of the base plate 20A, which overlaps in the Z direction with an area A2 where the multiple power modules 2 are arranged, as shown in Fig. 2. Furthermore, the area A1 faces the flat surface portion 14 of the case 10A. This increases the cooling efficiency of the power modules 2 by the cooler 1A. The multiple fins 30 arranged in this manner are provided on the base plate 20A.

[0044] However, the base plate 20A faces the flat surface portion 14 and not only positions the fins 30 on the flat surface portion 14, but also covers the grooves 12 and 13. As a result, in a conventional cooler equipped with such a base plate 20A, even if the cooling efficiency is high, the device itself may end up being large relative to the power module 2.

[0045] Therefore, in the cooler 1A, in order to increase the cooling efficiency and make the device itself smaller than the power module 2, the fins 30 are arranged at specific positions.

[0046] Next, the arrangement of the fins 30 will be described in detail with reference to FIGS.

[0047] Fig. 9 is a bottom view of the base plate 20A. Fig. 10 is an enlarged view of the X region shown in Fig. 9. Fig. 11 is a top view showing the positional relationship between the flat surface portion 14, the grooves 12 and 13, and the fins 30 provided in the case 10A of the cooler 1A.

[0048] 9 and 10, for ease of understanding, the bottom surface of the base plate 20A, i.e., the -Z plane, is shown facing upward. Also, in Fig. 11, for ease of understanding the positional relationship, the size of the fins 30 is emphasized and the number of fins 30 is significantly reduced. The outline of the base plate 20A is also shown, with the short side direction emphasized.

[0049] As shown in Figures 9 and 10, the multiple fins 30 are arranged in a staggered configuration. That is, multiple rows of fins 30 are formed, with the fins 30 arranged at a constant pitch, and between two adjacent rows of fins 30, one row is offset by half a pitch from the other. As a result, as shown in Figure 10, the multiple fins 30 are arranged around one fin 30, with other fins 30 located at the vertices of a regular hexagon H centered around that fin 30. This increases the arrangement density of the fins 30 and improves the cooling efficiency of the fins 30.

[0050] Furthermore, in the arrangement of the fins 30, the regular hexagon H has six sides, of which two opposing sides S1 and S2 are oriented in the direction in which the refrigerant flows in the flat surface portion 14, i.e., in the Y direction, which is the extension direction of the flow path. This prevents the refrigerant from stagnating when it flows through the flow path. As a result, the fins 30 allow the refrigerant to sufficiently hit all of the fins 30.

[0051] Furthermore, each fin 30 is formed in the shape of a regular hexagonal prism, and two of the six sides of the regular hexagonal prism in a cross section, sides S3 and S4, are oriented in a direction perpendicular to the refrigerant flow direction, i.e., in the X direction, which is the width direction of the flow channel. This makes it even more difficult for the refrigerant to stagnate. Furthermore, the fins 30 agitate the refrigerant at the corners of the regular hexagon in a cross section, thereby preventing the temperature boundary layer from becoming thick.

[0052] The corners of the regular hexagonal prism that is the shape of the fin 30 may be rounded. Also, it is sufficient that each side of the regular hexagonal prism is somewhat parallel to the axis of the prism.

[0053] Such an arrangement of the multiple fins 30 improves the cooling efficiency of the power module 2. Meanwhile, the multiple fins 30 are arranged in an area A1 that overlaps with an area A2 in which the power module 2 is arranged, as shown in Fig. 11. In the cooler 1A, the proportion of the size of the cooler 1A itself that is occupied by these areas A1 and A2 is increased to reduce the size of the cooler 1A itself relative to the power module 2, so that a distance D7 from the area A2 through the groove 12 or 13 to the short-side end face of the base plate 20A, i.e., the -Y end face or the +Y end face, is short.

[0054] In detail, in the cooler 1A, if the distance from the -Y end of the first fin 31 arranged upstream of the flattest surface portion 14 of the multiple fins 30, i.e., on the -Y side, to the -Y end of the flattest surface portion 14 of the case 10A is defined as D8, and the distance from the second fin 32 or 33 arranged toward the longitudinal end of the flattest surface portion 14 of the multiple fins 30, i.e., closest to the +X end or -X end, to the +X end or -X end of the flattest surface portion 14 is defined as D3, then distance D8 is shorter than distance D3.

[0055] Here, the distance D3 is smaller than the size of the gap between two adjacent fins 30. In other words, the distance D3 is smaller than the distance D9 from one fin 30 to the fin 30 adjacent to that fin 30. This prevents the refrigerant from passing through the flow path formed by the flat surface portion 14 between the second fin 32 arranged closest to the +X end of the flat surface portion 14 and the +X end of the flat surface portion 14, rather than through the gaps between the fins 30. Alternatively, the refrigerant is prevented from passing between the second fin 33 arranged closest to the -X end of the flat surface portion 14 and the -X end of the flat surface portion 14, rather than through the gaps between the fins 30. As a result, in the cooler 1A, heat exchange between the refrigerant and the fins 30 is prevented from slowing down, preventing a decrease in cooling efficiency.

[0056] In the cooler 1A, the distance D8 is shorter than the distance D3, thereby achieving a small distance D7 from the area A1 where the fins 30 are arranged to the -Y end face of the base plate 20A while maintaining high cooling efficiency. In other words, in the cooler 1A, the distance D7 from the area A2 where the power module 2 is arranged to the -Y end face of the base plate 20A is small. This allows the cooler 1A to achieve high cooling efficiency and a compact device itself. Furthermore, in the cooler 1A, the compact device itself shortens the wiring distance when the power module 2 is connected to an external electronic component, such as a capacitor, thereby reducing inductance. This increases the power conversion efficiency of the power module 2.

[0057] Furthermore, in the cooler 1A, the fins 30 are similarly arranged on the downstream side of the flat surface portion 14. That is, if the distance from the -Y end of the third fin 34, which is arranged on the most downstream side of the flat surface portion 14, i.e., the +Y side, among the multiple fins 30, to the -Y end of the flat surface portion 14 of the case 10A is defined as D10, then distance D10 is shorter than the above-mentioned distance D3. As a result, in the cooler 1A, high cooling efficiency and a compact device itself are achieved, similar to when the above-mentioned distance D8 is shorter than distance D3. Furthermore, the power conversion efficiency of the power module 2 is improved.

[0058] Such a relationship between distances D8 and D3 and a relationship between distances D10 and D3 are realized by the configuration of cooler 1A satisfying the following relational expressions (1) and (2). As is clear from this, it is desirable that the configuration of cooler 1A satisfy the following relational expressions (1) and (2).

[0059] If the distance from the center of the direction in which the refrigerant flows on the flat surface portion 14, i.e., the center line L3 in the Y direction, to the upstream end of the flat surface portion 14, i.e., the -Y end, is D1, and the distance from the center line L3 to the -Y end of the first fin 31 is D2, the distances D1 and D2 are expressed as follows: D1-D2<D3...relationship (1).

[0060] Alternatively, if the distance from the center line L3 to the downstream end of the flat surface portion 14, i.e., the +Y end, is D4, and the distance from the center line L3 to the +Y end of the third fin 34 is D5, the distances D4 and D5 are expressed as follows: D4-D5<D3...relationship (2).

[0061] By satisfying such relational expression (1) or (2), the cooler 1A can increase the cooling efficiency and reduce the size of the device itself. It can also increase the power conversion efficiency of the power module 2. Note that relational expression (1) or (2) includes relational expressions (1) and (2).

[0062] The grooves 12 and 13 described in the first embodiment are examples of a supply groove and a discharge groove as defined in the present disclosure. The flat surface portion 14 of the case 10A is an example of a bottom surface portion of a flow path as defined in the present disclosure. Furthermore, the base plate 20A is an example of a base as defined in the present disclosure. The regular hexagonal prism shape of the fin 30 is an example of a prism shape with a regular hexagonal cross section as defined in the present disclosure. The center line L3 is an example of a reference line as defined in the present disclosure. The through holes 121 and 131 are examples of a refrigerant supply port and a refrigerant discharge port as defined in the present disclosure. Furthermore, the inner wall of the −X end of the groove 12 in which the through hole 121 is formed is an example of a first inner wall as defined in the present disclosure. The −X end and +X end of the groove 12 are examples of a first end and a second end as defined in the present disclosure. Furthermore, the inner wall of the +X end of the groove 13 in which the through hole 121 is formed is an example of a second inner wall as defined in the present disclosure. The +X end of the groove 13 is an example of a third end in the present disclosure.

[0063] In the present disclosure, the region A1 on the plate surface of the base plate 20A where the fins 30 are arranged is also referred to as the flow path region. In the present disclosure, the region on the plate surface of the base plate 20A other than the region A1 on which the fins 30 are arranged and which faces the groove 13 when the base plate 20A is joined to the case 10A is referred to as the first groove region. In the present disclosure, the region on the plate surface of the base plate 20A other than the region A1 on which the fins 30 are arranged and which faces the groove 12 when the base plate 20A is joined to the case 10A is referred to as the second groove region.

[0064] As described above, in the cooler 1A according to the first embodiment, the flat surface portion 14 of the case 10A and the fins 30 of the base plate 20A satisfy the above-mentioned relational expressions (1) and (2). Therefore, the cooling efficiency is high and the device itself is small. As a result, the cooler 1A can not only sufficiently cool the power module 2 to be cooled, but also shorten the wiring of the power module 2, thereby improving the power conversion efficiency.

[0065] Furthermore, in the cooler 1A, the distance D3 from the second fin 32 or 33, among the multiple fins 30, that is disposed furthest in the longitudinal direction of the flat surface portion 14 to the longitudinal end of the flat surface portion 14 is shorter than the distance D9 that represents the size of the gap between two adjacent fins 30. This prevents the refrigerant from flowing into the gap between the second fin 32 or 33, disposed furthest in the longitudinal direction of the flat surface portion 14, and the longitudinal end of the flat surface portion 14, rather than into the spaces between the fins 30. As a result, the cooler 1A has high heat exchange efficiency between the fins 30 and the refrigerant. This results in high cooling efficiency for the power module 2.

[0066] In the cooler 1A, the multiple fins 30 are arranged around one fin 30, with other fins 30 located at the vertices of a regular hexagon H centered around that fin 30. The regular hexagon H has six sides, two opposing sides S1 and S2, that are oriented in the shorter direction of the flat surface portion 14, i.e., in the extension direction of the flow path, which is the direction in which the refrigerant flows. Therefore, in the cooler 1A, the refrigerant is less likely to stagnate when it flows through the flow path.

[0067] Furthermore, each of the fins 30 is formed in the shape of a regular hexagonal prism. Therefore, in the cooler 1A, the refrigerant is easily stirred when it flows through the flow path. As a result, the temperature boundary layer is prevented from becoming thick, and the heat exchange efficiency between the refrigerant and the fins 30 is high.

[0068] Furthermore, each of the fins 30 protrudes from the base plate 20A and abuts against the flat surface portion 14 of the case 10A. Therefore, each of the fins 30 not only radiates heat to the refrigerant, but also to the case 10A. The case 10A, like the base plate 20A, is made of a metal with high thermal conductivity, and therefore has high heat dissipation properties. As a result, the cooler 1A has high cooling efficiency for the power module 2.

[0069] In the cooler 1A, the longitudinal length L1 of the rectangular cross section of the grooves 12 and 13, i.e., the depth of the grooves 12 and 13, is greater than the lateral length L2 of the rectangular cross section of the grooves 12 and 13, i.e., the width of the groove 12. The depth of the grooves 12 and 13 is also greater than the size of the gap between the flat surface portion 14 and the base plate 20A, i.e., the height H1 of the flow path. Furthermore, the refrigerant is supplied from the bottom side of the groove 12, resulting in the refrigerant flowing from the bottom of the groove 12 toward the opening of the groove 12. Alternatively, the refrigerant is discharged from the opening side of the groove 13, resulting in the refrigerant flowing from the opening of the groove 13 toward the bottom of the groove 12. Therefore, the refrigerant is likely to spread throughout the entire extension direction of the groove 12 before flowing from the bottom of the groove 12 to the flow path, and is therefore less likely to be unevenly distributed. As a result, the refrigerant is likely to be distributed in the groove 12. Similarly, the refrigerant is likely to be collected in the groove 13.

[0070] Pipe fittings 122, 132, through which the refrigerant flows, are connected to the inner walls of the grooves 12, 13. The cross-sectional area of ​​the pipe fittings 122, 132 is smaller than the cross-sectional area of ​​the grooves 12, 13, as the inner diameter of the pipe fittings 122, 132 is smaller than the depth of the grooves 12, 13. Therefore, pressure loss in the grooves 12, 13 due to the flow of the refrigerant between the pipe fittings 122, 132 is small.

[0071] (Modification) In the first embodiment, the thickness T1 of the base plate 20A is greater than the height of the fins, i.e., the height H1 of the flow passages. However, the thickness T1 of the base plate 20A is not limited to this. For example, the thickness T1 of the base plate 20A may be equal to or less than the height H1 of the flow passages. In the first embodiment, six power modules 2 are provided on the base plate 20A. However, if there are fewer power modules 2, the base plate 20A is less likely to warp even if the thickness T1 of the base plate 20A is thinner. As a result, the base plate 20A may not warp even if the thickness T1 of the base plate 20A is equal to or less than the height H1 of the flow passages.

[0072] (Embodiment 2) In Embodiment 1, the region A1 in which the fins 30 are arranged overlaps with the flat surface portion 14 of the case 10A in a top view. That is, the multiple fins 30 are arranged within the flow path formed by the flat surface portion 14. However, the arrangement of the fins 30 is not limited to this. The arrangement of the fins 30 may be any arrangement that satisfies the above-described relational expressions (1) and (2). For example, the multiple fins 30 may be arranged in at least one of the internal spaces of the grooves 12 and 13, in addition to the flow path formed by the flat surface portion 14.

[0073] In the cooler 1B according to the second embodiment, the multiple fins 30 are arranged not only in the flow path formed by the flat surface portion 14 but also in the internal spaces of both the grooves 12 and 13 .

[0074] A cooler 1B according to the second embodiment will be described below with reference to Fig. 12 and Fig. 13. In the second embodiment, the configuration different from the first embodiment will be mainly described.

[0075] Fig. 12 is a cross-sectional view of a cooler 1B according to embodiment 2. Fig. 13 is a top view showing the positional relationship between the flat surface portion 14, grooves 12 and 13 provided on a case 10B included in the cooler 1B, and the fins 30. Note that Fig. 12 shows the cooler 1B when cut at the same location as the III-III cutting line shown in Fig. 1.

[0076] As shown in Fig. 12, the extension length of the flow path provided in the case 10B included in the cooler 1B, i.e., the length L4 of the flat surface portion 14, is shorter than the length L5 of the flat surface portion 14 of the first embodiment shown in Fig. 3. As a result, the region A1 in which the fins 30 provided on the underside of the base plate 20B are arranged does not overlap only with the flat surface portion 14 in a top view, as shown in Fig. 13. The region A1 overlaps not only with the flat surface portion 14 but also with the grooves 12 and 13 adjacent to the flat surface portion 14 in a top view. As a result, the multiple fins 30 protrude not only into the flow path formed by the flat surface portion 14 but also into the internal spaces of the grooves 12 and 13.

[0077] The cooler 1B having such an arrangement of fins 30 also satisfies the above-described relational expressions (1) and (2), as in the first embodiment. As a result, the distance D7 from the area A1 where the fins 30 are arranged to the -Y end face of the base plate 20B is short. That is, the distance D7 from the area A2 where the power module 2 is arranged to the -Y end face of the base plate 20B is short. This allows the cooler 1B to achieve a compact device itself. Furthermore, the cooler 1B shortens the wiring distance when the power module 2 is connected to external electronic components, thereby reducing inductance. As a result, the cooler 1B improves the power conversion efficiency of the power module 2.

[0078] Also in the cooler 1B, as in the first embodiment, the distance D3 from the second fin 32 or 33, among the multiple fins 30, that is arranged furthest in the longitudinal direction of the flat surface portion 14 to the longitudinal end of the flat surface portion 14 is smaller than the distance D9 from a fin 30 to the fin 30 adjacent to that fin 30, i.e., the size of the gap between two adjacent fins 30. As a result, in the cooler 1B, when the refrigerant flows, the refrigerant is prevented from flowing into the gap between the second fin 32 or 33 that is arranged furthest in the longitudinal direction of the flat surface portion 14 and the longitudinal end of the flat surface portion 14, rather than into the spaces between the fins 30. As a result, in the cooler 1B, the heat exchange efficiency between the fins 30 and the refrigerant is high, and the cooling efficiency of the power module 2 is high.

[0079] The base plate 20B is an example of the base referred to in the present disclosure.

[0080] As described above, in the cooler 1B according to the second embodiment, the flat surface portion 14 of the case 10B and the fins 30 of the base plate 20B satisfy the above-mentioned relational expressions (1) and (2), similarly to the first embodiment, and therefore the device itself is small. As a result, the wiring of the power module 2 can be shortened, and the power conversion efficiency can be improved.

[0081] Specifically, in the cooler 1B, the multiple fins 30 protrude not only into the flow path formed by the flat surface portion 14 but also into the internal spaces of the grooves 12 and 13. The fins 30 are arranged in an area A1 that overlaps with the power module 2 to be cooled. This allows the power module 2 to be positioned close to the end of the base plate 20B. This allows the cooler 1B to shorten the wiring distance when connecting the power module 2 to external electronic components, thereby improving power conversion efficiency.

[0082] Also, in the cooler 1B, as in the first embodiment, the distance D3 from the second fin 32 or 33, among the multiple fins 30, that is arranged furthest in the longitudinal direction of the flat surface portion 14, to the longitudinal end of the flat surface portion 14 is shorter than the distance D9 that represents the size of the gap between two adjacent fins 30. This prevents the refrigerant from flowing into the gap between the second fin 32 or 33 that is arranged furthest in the longitudinal direction of the flat surface portion 14 and the longitudinal end of the flat surface portion 14, rather than into the gap between the fins 30. As a result, the cooler 1B has high heat exchange efficiency between the fins 30 and the refrigerant. This results in high cooling efficiency for the power module 2.

[0083] (Modification) In the second embodiment, the multiple fins 30 are arranged not only in the flow path formed by the flat surface portion 14 but also in the internal spaces of both the grooves 12 and 13. However, the multiple fins 30 may be arranged in the flow path formed by the flat surface portion 14 as well as in the internal space of at least one of the grooves 12 and 13.

[0084] FIG. 14 is a cross-sectional view of a modified example of the cooler 1B according to the second embodiment.

[0085] 14 , the multiple fins 30 may be arranged in the internal space of the grooves 13 in addition to the flow paths formed by the flat surface portions 14. In this configuration, when the refrigerant flows through the flow paths formed by the flat surface portions 14, the refrigerant exchanges heat with the fins 30 and flows downstream, making it less likely that the cooling performance of the cooler 1B will be reduced. Even with this configuration, the refrigerant that flows in from the flow paths formed by the flat surface portions 14 flows through the grooves 13 due to inertia, so there is little impact on the cooling performance of the cooler 1B. Therefore, when the multiple fins 30 are arranged in the internal space of at least one of the grooves 12 and 13 in addition to the flow paths formed by the flat surface portions 14, it is desirable that they be arranged in the internal space of the groove 13.

[0086] (Embodiment 3) In Embodiments 1 and 2, through-holes 121 and 131 are formed in the inner walls in the extension direction of grooves 12 and 13, penetrating from the inner walls to the external space. Pipe fittings 122 and 132 are fitted into these through-holes 121 and 131. As a result, refrigerant flows through grooves 12 and 13 in the extension direction of grooves 12 and 13, i.e., the X direction. However, the direction of refrigerant flow through grooves 12 and 13 is not limited to this. Groove 12 may be a supply groove that supplies refrigerant to the flow path. In this case, since the flow path and the supply groove are adjacent to each other, it is desirable that the refrigerant flow in the supply groove be from the bottom toward the opening. Groove 13 may be a discharge groove that discharges refrigerant from the flow path. In this case, since the flow path and the discharge groove are adjacent to each other, it is desirable that the refrigerant flow in the discharge groove be from the opening toward the bottom.

[0087] In the cooler 1C according to the third embodiment, a through hole for supplying the refrigerant is provided in the side wall of the groove 12. Also, a through hole for discharging the refrigerant is provided in the side wall of the groove 13.

[0088] A cooler 1C according to the third embodiment will be described below with reference to Fig. 15 and Fig. 16. In the third embodiment, the configuration different from the first and second embodiments will be mainly described.

[0089] Fig. 15 is a perspective view of a cooler 1C according to embodiment 3. Fig. 16 is a cross-sectional view taken along the line XVI-XVI shown in Fig. 15.

[0090] As shown in FIGS. 15 and 16, pipe joints 123 and 133 for supplying a refrigerant are connected to the end faces of the case 10C in the shorter direction.

[0091] As shown in FIG. 16 , the pipe fitting 123 is connected to the groove 12. Specifically, the groove 12 is formed in a rectangular shape in a YZ cross section. The groove 12 extends in the X direction while maintaining its cross-sectional shape. As a result, the groove 12 has two flat side walls facing each other in the Y direction. A through-hole 124 is formed in the side wall that is closer to the outside of the case 10C. The through-hole 124 is formed on the −Z plane of the groove 12, i.e., in a position that contacts the bottom. Furthermore, the pipe fitting 123 is fitted into the through-hole 124. As a result, when a refrigerant flows through the pipe fitting 123, the refrigerant is supplied to the bottom of the groove 12. As a result, the refrigerant flows in the groove 12 from the bottom toward the opening.

[0092] As described in the first embodiment, the groove 12 has a rectangular shape in a YZ cross section, with the longitudinal direction oriented in the Z direction and the lateral direction oriented in the Y direction. The longitudinal length L1 of the rectangle in the YZ cross section is greater than the lateral length L2. That is, the depth of the groove 12 is greater than the width. As a result, when the refrigerant flows in the direction from the bottom toward the opening of the groove 12, resistance to the refrigerant increases on the opening side of the groove 12. This makes it easier for the refrigerant to spread in the extension direction of the groove 12, i.e., in the X direction, and is less likely to be unevenly distributed. As a result, the refrigerant is easily distributed in the groove 12.

[0093] On the other hand, the pipe fitting 133 is connected to the groove 13. Specifically, the groove 13 is formed in a shape symmetrical to the groove 12 in the front-to-back direction. As a result, the groove 13 also has two flat side walls facing each other in the Y direction. A through hole 134 is formed in the side wall of the two side walls that is located closer to the outside of the case 10C. Like the through hole 124, the through hole 134 is formed in a position that contacts the bottom of the groove 13. The pipe fitting 133 is fitted into the through hole 134. As a result, when a refrigerant flows through the cooler 1C, the pipe fitting 133 discharges the refrigerant from the bottom of the groove 13.

[0094] Like groove 12, groove 13 has a depth greater than a width. As a result, when the refrigerant flows toward the bottom of groove 13, the resistance to the refrigerant is greater on the bottom side of groove 13 than on the opening side. As a result, the refrigerant tends to spread in the X direction, which is the extension direction of groove 13, and is less likely to be unevenly distributed. This makes it easier for the refrigerant to collect in groove 12.

[0095] The base plate 20C is an example of the base referred to in the present disclosure.

[0096] As described above, in the cooler 1C according to the third embodiment, the pipe joint 123 is connected to the side wall of the groove 12 and supplies the refrigerant to the bottom side of the groove 12. In the cooler 1C, similarly to the coolers 1A and 1B, the depth of the groove 12 is greater than the width of the groove 12. Therefore, when the refrigerant flows from the bottom of the groove 12 to the opening side of the groove 12, the refrigerant is likely to be distributed in the extending direction of the groove 12.

[0097] Furthermore, in the cooler 1C, the pipe fittings 133 are connected to the side walls of the grooves 13, and the refrigerant is discharged from the bottom side of the grooves 13. The depth of the grooves 13 is also greater than the width of the grooves 13. Therefore, when the refrigerant flows from the openings of the grooves 13 to the bottom side of the grooves 13, the refrigerant tends to collect in the extending direction of the grooves 13.

[0098] (Embodiment 4) In embodiments 1-3, the cases 10A-10C are formed from a metal with high thermal conductivity from the flat surface portion 14 to the bottom. This improves the heat dissipation properties of the cases 10A-10C. However, the cases 10A-10C are not limited to this. The cases 10A-10C may have therein a flat surface portion 14 through which the refrigerant flows, i.e., the bottom surface of the flow path, a groove 12 adjacent to the upstream end of the bottom surface portion for supplying the refrigerant to the flow path, and a groove 13 adjacent to the downstream end of the bottom surface portion for discharging the refrigerant from the flow path. Therefore, the lower structure of the flat surface portion 14 of the cases 10A-10C may be any structure as long as it satisfies this condition.

[0099] In the fourth embodiment, the flat surface portion 14 is formed of a metal plate.

[0100] A cooler 1D according to the fourth embodiment will be described below with reference to Fig. 17. In the fourth embodiment, the configuration different from the first to third embodiments will be mainly described.

[0101] Fig. 17 is a cross-sectional view of a cooler 1D according to embodiment 4. Fig. 17 shows the cooler 1D when cut along the same line as the III-III cut line shown in Fig. 1.

[0102] 17, in a cooler 1D, a case 10D has a box shape with an open top. The case 10D has a partition wall 16 that divides an internal space 15 of the box into two.

[0103] Specifically, case 10D has an elongated rectangular parallelepiped internal space 15 with its longitudinal direction oriented left-right, i.e., in the X direction. Partition wall 16 is disposed in this elongated rectangular parallelepiped internal space 15, dividing the internal space 15 into two. More specifically, partition wall 16 has a flat plate shape with its plate surface facing the Y direction. Partition wall 16 is also disposed in the center of internal space 15 of case 10D in the Y direction. As a result, partition wall 16 divides internal space 15 of case 10D into two.

[0104] One of the two spaces of the internal space 15 divided by the partition wall 16 of the case 10D, i.e., the first space 151 on the -Y side, is connected to a pipe fitting 122 (not shown in FIG. 17 ). As described in the first embodiment, the pipe fitting 122 is connected to a pipe extending from an external device (not shown), and a refrigerant is supplied from the external device. In this way, the refrigerant is supplied to the first space 151.

[0105] On the other hand, the other space of the divided internal space 15, i.e., the second space 152 on the +Y side, is connected to a pipe joint 132 (not shown in FIG. 17 ). As described in the first embodiment, the pipe joint 132 is connected to a pipe extending from an external device (not shown) and is capable of discharging the refrigerant to the external device. As a result, the refrigerant can be discharged from the second space 152.

[0106] On the other hand, the cooler 1D includes a metal plate 17 that covers most of the internal space 15 of the case 10D and abuts against the fins 30 of the base plate 20D to form a flow path.

[0107] Specifically, the metal plate 17 is made of a metal material with high thermal conductivity and has a rectangular plate shape with a width W2 smaller than the width W1 of the internal space 15 of the case 10D. Although not shown, the length of the metal plate 17 is the same as the length of the internal space 15 of the case 10D in the longitudinal direction, i.e., the X-direction. The metal plate 17 is fitted into the internal space 15 of the case 10D. The height H2 of the partition wall 16 described above is smaller than the height H3 of the internal space 15 by the sum of the height H1 of the flow path described in the first embodiment and the thickness T2 of the metal plate 17. As a result, when the metal plate 17 is fitted into the internal space 15 and abuts against the +Z end of the partition wall 16, it is positioned on the -Z side of the +Z end face of the case 10D by the height H1 of the flow path. The metal plate 17 is fixed to the partition wall 16 while abutting against the +Z end of the partition wall 16. For example, the metal plate 17 may be brazed to the partition wall 16 or fixed to the partition wall 16 via an elastic body such as rubber or a spring.

[0108] The base plate 20D abuts against the +Z end face of the case 10D and covers the internal space 15 of the case 10D. As a result, the metal plate 17 faces the base plate 20D at a distance of the height H1 of the flow path, and the fins 30 of the base plate 20D abut against it. As a result, the metal plate 17 forms a flow path together with the base plate 20D. With this configuration, the metal plate 17 forms the flat surface portion 14 of the flow path.

[0109] As described above, width W2 of metal plate 17 is smaller than width W1 of internal space 15. As a result, metal plate 17 forms a gap with the inner wall on the -Y side of internal space 15 of case 10D. As a result, metal plate 17 forms adjacent grooves 12 on the -Y side of metal plate 17. Grooves 12 are connected to first space 151, and therefore are deeper than thickness T2 of metal plate 17. Then, as refrigerant is supplied to first space 151 from pipe joint 122, grooves 12 are filled with refrigerant, and the refrigerant is supplied to the flow path of metal plate 17.

[0110] Furthermore, metal plate 17 forms a gap not only with the inner wall on the -Y side of internal space 15 of case 10D, but also with the inner wall on the +Y side. As a result, metal plate 17 forms grooves 13 adjacent to the +Y side of metal plate 17. Grooves 13 are connected to second space 152, and therefore are deeper than thickness T2 of metal plate 17. Second space 152 is capable of discharging the refrigerant from pipe joint 132, so that when the refrigerant flows in from the flow path of metal plate 17, the refrigerant is discharged from pipe joint 132.

[0111] In case 10D, metal plate 17 has such a configuration, and as in embodiments 1-3, the width of the +Z side of grooves 12 and 13, i.e., the width of the opening side, is narrower than the width of the bottom side of grooves 12 and 13, i.e., the width of first space 151 and second space 152. Therefore, when the refrigerant flows from first space 151 to the opening side of groove 12, the refrigerant tends to be distributed in the extension direction of groove 12, i.e., in the X direction of groove 12. Furthermore, when the refrigerant flows from the opening of groove 13 to second space 152, the refrigerant tends to be collected in the extension direction of groove 13, i.e., in the X direction.

[0112] The base plate 20D is an example of a base as referred to in the present disclosure, and the metal plate 17 is an example of a plate-like body as referred to in the present disclosure.

[0113] As described above, the case 10D according to the fourth embodiment has the metal plate 17 therein, which faces the base plate 20D and forms the flat surface portion 14 for forming the flow path. The grooves 12 and 13 are provided at one end and the other end of the metal plate 17, and are formed deeper than the thickness T2 of the metal plate 17. In the cooler 1D, the flat surface portion 14 can be formed by the metal plate 17, which makes it easy to manufacture.

[0114] Furthermore, case 10D has an internal space 15 adjacent to metal plate 17 on the side opposite to the side where metal plate 17 faces base plate 20D, and internal space 15 is divided into a first space 151 and a second space 152 by a partition wall 16 abutting metal plate 17. Metal plate 17 forms a gap between internal space 15 and grooves 12 and 13 connecting first space 151 and second space 152. Cooler 1D is easy to manufacture because grooves 12 and 13 can be formed simply by dividing internal space 15 with partition wall 16 and covering internal space 15 with metal plate 17 while leaving a gap.

[0115] In the cooler 1D as well, the width of the opening side of the grooves 12 and 13 is narrower than the width of the bottom side of the grooves 12 and 13. Therefore, the refrigerant is easily distributed in the groove 12. In addition, the refrigerant is easily collected in the groove 13.

[0116] In the fourth embodiment, the metal plate 17 may be replaced with another plate-like body. That is, as described above as an example of the plate-like body referred to in the present disclosure, the metal plate 17 may be a plate formed of a material other than a metal material, for example, a resin material.

[0117] Although the coolers 1A-1D and semiconductor devices according to the embodiments of the present disclosure have been described above, the coolers 1A-1D and semiconductor devices are not limited to this.

[0118] For example, in embodiments 1 and 2, grooves 12 and 13 have a cross-sectional shape that is a combination of a rectangle and a circle. Furthermore, in embodiments 3 and 4, grooves 12 and 13 have a cross-sectional shape that is a rectangle with its longitudinal direction oriented in the depth direction or a rectangle with its longitudinal direction oriented in the width direction. However, the shapes of grooves 12 and 13 are not limited to these. As described above, groove 12 may be a supply groove that supplies refrigerant to the flow path. In this case, since the flow path and the supply groove are adjacent to each other, it is desirable that the refrigerant flow in the supply groove be from the bottom toward the opening. Furthermore, as described above, groove 13 may be a discharge groove that discharges refrigerant from the flow path. In this case, since the flow path and the discharge groove are adjacent to each other, it is desirable that the refrigerant flow in the discharge groove be from the opening toward the bottom.

[0119] 18 to 20 are cross-sectional views of first to third modified examples of the grooves 12 and 13 formed in the case 10A of the cooler 1A.

[0120] 18 , grooves 12 and 13 may be rectangular in cross section with the longitudinal direction oriented in the depth direction, and pipe fittings 122 and 132 may be connected from a direction perpendicular to the cross section, i.e., from the X direction perpendicular to the YZ cross section. This is because, in such a configuration, when the refrigerant flows in the depth direction, resistance to the refrigerant is high, and the refrigerant is easily distributed in the extension direction of grooves 12 and 13. In this case, it is preferable that the width in the Y direction and the depth in the Z direction of grooves 12 and 13 of the rectangular in YZ cross section be larger than the inner diameter of pipe fittings 122 and 132.

[0121] 19 and 20, the grooves 12 and 13 may have a cross-sectional shape in which a small rectangle is connected to a large rectangle. Specifically, the grooves 12 and 13 may have a cross-sectional shape in which a second rectangle having a smaller Y-direction width is adjacent to the +Z side of a first rectangle having a larger Y-direction width. In this case, as shown in FIG. 19, pipe fittings 122 and 132 having an inner diameter smaller than the Y-direction width and Z-direction height of either the first rectangle or the second rectangle may be connected. Alternatively, as shown in FIG. 20, pipe fittings 122 and 132 having a rectangular opening in cross-sectional view may be connected.

[0122] Furthermore, in embodiments 1-4, grooves 12 and 13 extend with the same cross-sectional shape. However, the shapes of grooves 12 and 13 are not limited to this. As described above, groove 12 may be a supply groove that supplies refrigerant to the flow path. Furthermore, groove 13 may be a discharge groove that discharges refrigerant from the flow path. Therefore, the cross-sectional shapes of grooves 12 and 13 may change in the extension direction.

[0123] FIG. 21 is a cross-sectional view of a fourth modified example of the groove 12 formed in the case 10A of the cooler 1A.

[0124] 21 , the groove 12 may be configured such that a first groove having a rectangular shape with its longitudinal direction oriented in the Z direction in cross section and a semicircle protruding from a side extending in the longitudinal direction of the rectangle is connected to the +X side of a through hole 121 that is circular in cross section and to which a pipe fitting 122 is connected. Furthermore, a second groove having only a rectangular shape with its longitudinal direction oriented in the Z direction in cross section may be connected to the +X side of the first groove. In this configuration, the first groove having a shape that combines the circular cross section of the through hole 121 and the rectangular cross section of the second groove is located between the through hole 121 that is circular in cross section and the second groove that is rectangular in cross section, making manufacturing easier.

[0125] In embodiments 1-4, all of the fins 30 are regular hexagonal prisms, and as a result, all of the fins 30 have the same shape. However, the fins 30 are not limited to this. It is sufficient that a plurality of fins 30 are arranged on the surface of the base plates 20A-20D opposite the surface on which the object to be cooled is provided. For this reason, the fins 30 do not all have to have the same shape, and a plurality of types of fins 30 with different shapes may be mixed.

[0126] FIG. 22 is a top view showing the positional relationship between the end of the flat surface portion 14 of the case 10A included in the cooler 1A and the fins 30 in a modified example.

[0127] As shown in FIG. 22 , the flat surface portion 14 may include a mixture of multiple fins 30 in the shape of regular hexagonal prisms and fins 40 shaped like regular hexagonal prisms cut along their axis. As described in the first embodiment, the multiple fins 30 are arranged in a staggered pattern. As a result, a group of fins 30 arranged in a row in the X direction are arranged in the Y direction. Furthermore, rows of fins 30 arranged at a constant pitch in the X direction are offset in the X direction by half a pitch from adjacent rows in the Y direction. This may result in regions A3 at the end of the flat surface portion 14 where every other row lacks fins 30. Furthermore, these regions A3 may not be large enough to accommodate complete fins 30. Therefore, as shown in FIG. 22 , incomplete fins 40 are arranged in each region A3. Each fin 40 has a trapezoidal cross-sectional columnar shape, resulting from cutting a regular hexagonal prism along its axis. This makes the distance from the end of the flat surface portion 14 to the nearest fin 30 the same as the distance from the end of the flat surface portion 14 to the fin 40, preventing the refrigerant from passing through each of the regions A3.

[0128] In this way, a plurality of types of fins 30, 40 with different shapes may be mixed.

[0129] In addition, in embodiments 1-4, the fin 30 is a regular hexagonal prism, but the fin 30 may also be a prism whose axial cross section is a regular hexagon. In this case, as long as the axial cross section is a regular hexagon, the fin 30 may become thinner toward the tip.

[0130] Furthermore, in the embodiments 1-4, the cooling target of the cooler 1A-1D is the power module 2, but the cooler 1A-1D is not limited to this. The cooling target may be anything that is cooled by heat exchange with a refrigerant. Therefore, the cooling target of the cooler 1A-1D may be a semiconductor device other than the power module 2, such as a light-emitting diode.

[0131] In the embodiment 1-4, the configuration of the coolers 1A-1D is described when the longitudinal direction of the rectangular base plates 20A-20D is oriented in the left-right direction and the lateral direction is oriented in the front-rear direction. However, this orientation is for convenience in describing the configuration of the coolers 1A-1D. As long as the relative positional relationship between the components of the coolers 1A-1D is maintained, the orientation of the coolers 1A-1D is arbitrary.

[0132] The present disclosure allows various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Furthermore, the above-described embodiments are intended to explain the present disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of the disclosure equivalent thereto are considered to be within the scope of the present disclosure.

[0133] 1A-1D Cooler, 2 Power module, 10A-10D Case, 11 Recess, 12, 13 Groove, 14 Flat surface portion, 15 Internal space, 16 Partition wall, 17 Metal plate, 20A-20D Base plate, 21 Step, 30 Fin, 31 First fin, 32, 33 Second fin, 34 Third fin, 40 Fin, 121 Through hole, 122 Pipe joint, 123 Pipe joint, 124 Through hole, 131 Through hole, 132 Pipe joint, 133 Pipe joint, 134 Through hole, 151 First space, 152 Second space, A1-A3 Area, L1, L2 Length, L3 Center line, D1-D5 Distance, D6 Diameter, D7-D10 Distance, H Regular hexagon, H1-H3 Height, S1-S4 sides, T1, T2 thickness, W1, W2 width.

Claims

1. A base for a cooler that covers the bottom portion of a case having a bottom portion including a flow path through which a coolant flows from an upstream end to a downstream end, and having a heating element provided on one side and a plurality of fins provided on the other side, wherein the other side faces the bottom portion of the case, The plurality of fins are provided in a flow path region of the other surface of the base, at least facing the bottom surface portion, and are arranged in the flow path region that overlaps with the region of the base on one surface where the heating element is provided, when viewed from a direction perpendicular to the other surface, and are arranged in the direction of extension of the flow path from the upstream end to the downstream end of the bottom surface portion, and are arranged in the width direction of the flow path perpendicular to the direction of extension of the flow path, when viewed from a direction perpendicular to the other surface. When D1 is the distance from a reference line set on the bottom surface portion and extending in the width direction to the upstream end of the bottom surface portion, D2 is the distance from the reference line to the upstream end of the first fin, which is arranged furthest upstream among the plurality of fins, and D3 is the distance from the end of the flow path in the width direction to the second fin, which is closest to that end among the plurality of fins, the relationship D1 - D2 < D3 is satisfied. Alternatively, if D4 is the distance from the reference line to the downstream end of the bottom portion, and D5 is the distance from the reference line to the downstream end of the third fin, which is arranged furthest downstream among the plurality of fins, then the relationship D4 - D5 < D3 is satisfied. Cooler base.

2. The distance from the second fin to the end of the bottom portion of the flow path closest to the second fin in the width direction is smaller than the gap between two adjacent fins among the plurality of fins. The base of the cooler according to claim 1.

3. The case has a discharge groove provided at the downstream end of the bottom portion, which is recessed from the downstream end and allows the refrigerant flowing in from the flow path to flow into the interior and be discharged, The other surface of the base faces the bottom portion of the case, The plurality of fins are arranged in the flow channel region on the other surface of the base and in the first groove region on the other surface facing the discharge groove. A base for a cooler according to claim 1 or 2.

4. The case has a discharge groove provided at the downstream end of the bottom portion, which is recessed from the downstream end and allows the refrigerant flowing in from the flow path to flow into the interior and be discharged, The other surface of the base faces the bottom portion of the case, The plurality of fins are arranged in the flow channel region on the other surface of the base and in the second groove region on the other surface facing the discharge groove. A base for a cooler according to claim 1 or 2.

5. The case has a supply groove provided at the upstream end of the bottom portion, which is recessed from the upstream end and supplies the refrigerant flowing inside to the flow path, and a discharge groove provided at the downstream end of the bottom portion, which is recessed from the downstream end and discharges the refrigerant flowing in from the flow path into the interior, The plurality of fins are arranged in the flow channel region of the other surface of the base, the first groove region facing the discharge groove on the other surface, and the second groove region facing the supply groove on the other surface. A base for a cooler according to claim 1 or 2.

6. The plurality of fins are arranged around one fin such that the other fins are positioned at the vertices of a regular hexagon centered on that fin. The regular hexagon has a shape in which two of its six sides are oriented in the direction of extension of the flow path. A base for a cooler according to claim 1 or 2.

7. Each of the aforementioned fins has the shape of a column with a regular hexagonal cross-section. Of the six sides of the regular hexagon, two sides are oriented in the width direction of the flow path. The base of the cooler according to claim 6.

8. The case has a supply groove provided at the upstream end of the bottom portion, which is recessed from the upstream end and supplies the refrigerant flowing inside to the flow path, The depth of the supply groove is greater than the width of the supply groove and greater than the height from the bottom portion of the flow path to the other surface of the base. In the supply groove, the refrigerant flows from the bottom of the supply groove toward the opening of the supply groove, which is covered by the base of the supply groove. A base for a cooler according to claim 1 or 2.

9. The supply groove is provided on the bottom side of the supply groove's opening and has a first inner wall in which a refrigerant supply port smaller than the width and depth of the supply groove is formed. The base of the cooler according to claim 8.

10. The supply groove extends in the width direction of the flow path, The first inner wall is formed at the first end of the supply groove in the extending direction, The base of the cooler according to claim 9.

11. The supply groove extends in the width direction of the flow path, The width direction of the supply groove is oriented toward the extension direction of the flow path, The first inner wall is a side wall of the supply groove oriented in the direction of extension of the flow path. The base of the cooler according to claim 9.

12. The supply groove has a shape at its first end in the extending direction where, in cross-sectional view, a rectangle with its longitudinal direction oriented toward the depth direction of the supply groove and a circle having a diameter smaller than the longitudinal length of the rectangle and larger than the short length of the rectangle overlap, and further, at its second end opposite to the first end in the extending direction, the supply groove has a rectangular shape in cross-sectional view that is the same as the shape of the first end in cross-sectional view. The circle is in contact with the first side of the rectangle that extends in the longitudinal direction and is located on the side opposite to the bottom portion of the flow path, and is also in contact with the second side located on the bottom side of the rectangle. The first inner wall is formed at the first end of the supply groove, The refrigerant supply port has a diameter smaller than the diameter of the circle. The base of the cooler according to claim 9.

13. The aforementioned case is, A supply groove is provided at the upstream end of the bottom portion, which is recessed from the upstream end and supplies the refrigerant flowing inside to the flow path, A discharge groove is provided at the downstream end of the bottom portion, which is recessed from the downstream end and allows the refrigerant flowing in from the flow path to flow inward and be discharged, Opposite the base is a plate-like body that forms the bottom portion of the flow path, It has, The supply groove is provided at one end of the plate-like body and is formed to be deeper than the thickness of the plate-like body. The discharge groove is provided at the other end of the plate-like body opposite to one end, and is formed to be deeper than the thickness of the plate-like body. A base for a cooler according to claim 1 or 2.

14. The case has an internal space adjacent to the plate-like body on the side opposite to the side of the plate-like body that faces the base, The aforementioned internal space is divided into a first space and a second space by a partition wall that abuts against the plate-like body. The supply groove is connected to the first space, and refrigerant is supplied to the first space from an external device through the supply groove. The discharge channel is connected to the second space, and a pipe extending to the outside is connected to the second space, thereby allowing refrigerant to be discharged from the discharge channel to the outside. The base of the cooler according to claim 13.

15. The case has a discharge groove provided at the downstream end of the bottom portion, which is recessed from the downstream end and allows the refrigerant flowing in from the flow path to flow into the interior and be discharged, The depth of the discharge groove is greater than the width of the discharge groove, and greater than the height of the flow path from the bottom surface portion of the flow path to the other surface of the base. In the discharge channel, the refrigerant flows from the opening of the discharge channel, which is covered by the base of the discharge channel, toward the bottom of the discharge channel. A base for a cooler according to claim 1 or 2.

16. The discharge groove is provided on the bottom side of the opening of the discharge groove and has a second inner wall in which a refrigerant outlet smaller than the width and depth of the discharge groove is formed. The base of the cooler according to claim 15.

17. The discharge groove extends in the width direction of the flow path, The second inner wall is formed at the third end of the discharge groove in the extending direction, The base of the cooler according to claim 16.

18. The discharge groove extends in the width direction of the flow path, The width direction of the discharge groove is oriented toward the extension direction of the flow path, The second inner wall is a side wall of the discharge groove oriented in the direction of extension of the flow path. The base of the cooler according to claim 16.

19. The plurality of fins are in contact with the bottom portion of the flow path of the case. A base for a cooler according to claim 1 or 2.

20. The base has the shape of a plate that is thicker than the height of the flow channel from the bottom surface portion of the flow channel to the other surface of the base. A base for a cooler according to claim 1 or 2.

21. The case has a supply groove provided at the upstream end of the bottom portion, which is recessed from the upstream end and supplies the refrigerant flowing inside to the flow path, In the supply groove, the refrigerant flows from the bottom of the supply groove toward the opening of the supply groove which is covered by the base of the supply groove. The width of the supply groove is smaller than the depth of the supply groove. The height of the flow path from the bottom portion of the flow path to the other surface of the base is smaller than the width of the supply groove. The fin has a columnar shape with a diameter smaller than the height of the flow path. A base for a cooler according to claim 1 or 2.

22. A base of the cooler according to claim 1 or 2, The case has a rectangular shape with two opposing sides facing upstream and downstream, Equipped with, cooler.

23. The cooler according to claim 22, The aforementioned heating element, Equipped with, The aforementioned heating element is a semiconductor element. Semiconductor equipment.