heat sink

Abstract

To provide a heat sink capable of increasing a heat transfer area and improving heat dissipation performance without increasing the number of parts and the size of the parts or device.SOLUTION: A heat sink 2 includes a plurality of grooves 4 in a fin region 2b, which increases the heat transfer area and improves the heat dissipation performance. Furthermore, since the longitudinal direction Y of the grooves 4 is not parallel to the inflow direction A of a refrigerant, a part of the inflowing refrigerant collides with a longitudinal side surface 41 of the grooves 4 and is stirred and mixed, thereby further improving the cooling efficiency. The heat sink 2 may also have grooves 4c arranged such that the longitudinal direction Y3 is parallel to the inflow direction A of the refrigerant.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This application relates to a heat sink.

Background Art

[0002] In recent years, with the miniaturization and high performance of electronic devices, the heat generation density of heat generating elements such as CPUs, LSIs, and power semiconductor devices has been increasing and tending to become high temperature. In an in-vehicle inverter, in addition to the increasing heat generation density of the power module, it is exposed to heat damage from various other heat sources, so a liquid-cooled cooler with higher cooling performance than a conventional air-cooled cooler is often used.

[0003] A liquid-cooled cooler includes a heat sink having a fin region on one surface and an electronic component attachable on the other surface, and is configured such that the fin region is disposed in a refrigerant flow path. As a method for improving the heat dissipation performance in such a liquid-cooled cooler, there is a method of increasing the heat transfer area to the refrigerant by making the fin shape complex or increasing the number of parts. There is also a method known for improving the cooling efficiency by disturbing the flow of the refrigerant passing through the fin region to stir the refrigerant in the refrigerant flow path.

[0004] For example, in Patent Document 1, in a stacked cooler in which a plurality of inner fins stacked in the stacking direction are disposed in a refrigerant flow path, the heat transfer area is increased by making at least one inner fin a wavy fin. Further, according to such a structure, since a part of the refrigerant advances while meandering along the wavy fin, the refrigerant is likely to mix in the refrigerant flow path, and the cooling efficiency is further improved.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] One simple way to increase the heat transfer area of ​​a heatsink is to increase the height of the fins to increase their surface area. However, as the height of the fins increases, the heat dissipation at the fin tips decreases, leading to a decrease in fin efficiency. Furthermore, the increased cross-sectional area of ​​the flow path causes a decrease in the refrigerant flow velocity. Furthermore, methods that increase the heat transfer area by increasing the number of parts and making the fin configuration more complex, as described in Patent Document 1, have the problem of making the cooler larger.

[0007] This application discloses a technology for solving the above-mentioned problems, and aims to provide a heat sink that can increase the heat transfer area without increasing the number of parts or the size of the parts or device, thereby improving heat dissipation performance. [Means for solving the problem]

[0008] The heat sink disclosed herein has a fin region on one side having a plurality of pin fins, and an electronic component can be attached to the other side, and is a heat sink that transfers heat generated by the electronic component to a coolant flowing through the fin region, wherein the fin region has a plurality of grooves on one side Furthermore, the grooves have different depth dimensions in a cross-section parallel to the longitudinal direction of the groove. . [Effects of the Invention]

[0009] According to the heat sink disclosed herein, by having multiple grooves in the fin region, the heat transfer area can be increased without increasing the number of parts or the size of the parts or device, thereby improving heat dissipation performance. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing a heat sink according to Embodiment 1. [Figure 2] This is an exploded perspective view showing a power conversion device equipped with a heat sink according to Embodiment 1. [Figure 3] This is a perspective view showing the fin region of the heat sink according to Embodiment 1. [Figure 4] This is a plan view showing the fin region of a heat sink according to Embodiment 1. [Figure 5] This is a plan view showing a modified example of the fin region of the heat sink according to Embodiment 1. [Figure 6] This is a plan view showing another modified example of the fin region of the heat sink according to Embodiment 1. [Figure 7] This is a perspective view showing the fin region of the heat sink according to Embodiment 2. [Figure 8] This is a plan view showing the fin region of the heat sink according to Embodiment 2. [Figure 9] This is a perspective view showing the fin region of the heat sink according to Embodiment 3. [Figure 10] This is a plan view showing the fin region of the heat sink according to Embodiment 3. [Figure 11] This is a cross-sectional view showing an example of a fin structure according to Embodiment 4. [Figure 12] This is a cross-sectional view showing an example of a groove structure according to Embodiment 4. [Figure 13] This is a cross-sectional view showing a modified example of the groove structure according to Embodiment 4. [Figure 14] This is a cross-sectional view showing another modified example of the groove structure according to Embodiment 4. [Figure 15] This is a cross-sectional view showing yet another modified example of the groove structure according to Embodiment 4. [Modes for carrying out the invention]

[0011] Embodiment 1. Hereinafter, the heat sink according to Embodiment 1 will be described based on the drawings. FIG. 1 is a perspective view showing the heat sink according to Embodiment 1, FIG. 2 is an exploded perspective view showing a power conversion device including the heat sink according to Embodiment 1, and FIGS. 3 and 4 are a perspective view and a plan view showing the fin region of the heat sink according to Embodiment 1. In each figure, the same or corresponding parts are denoted by the same reference numerals.

[0012] The heat sink 2 has a fin region 2b provided with a plurality of pin fins (hereinafter, fins 3) on one surface (the lower surface in FIG. 1). The fin region 2b occupies the entire one surface and is rectangular. Further, the heat sink 2 can attach the electronic component 1 to the other surface (hereinafter, the base surface 2a), and transfers the heat generated by the electronic component 1 to the refrigerant flowing through the fin region 2b. Furthermore, the fin region 2b has a plurality of grooves 4 provided on one surface.

[0013] The heat sink 2 is made of a material with good thermal conductivity such as aluminum or copper, and is manufactured by methods such as forging, casting, die casting, and metal powder injection molding (MIM). In any manufacturing method, a mold is used, and the fins 3 and the grooves 4 are formed simultaneously.

[0014] The electronic component may not be particularly limited, and examples thereof include semiconductor elements such as power field effect transistors (FETs) and insulated gate bipolar transistors (IGBTs), or semiconductor modules incorporating semiconductor elements such as IGBTs and diodes. The electronic component is fixed to the base surface 2a by metal bonding, grease, or adhesion.

[0015] The power conversion device 20 shown in FIG. 2 is, for example, an in-vehicle inverter, and includes a liquid-cooled cooler 10 composed of a heat sink 2 and a water jacket 5. The water jacket 5 is formed using a material with good thermal conductivity such as aluminum or copper, similar to the heat sink 2. The heat sink 2 is joined to the water jacket 5 having a refrigerant inlet 6 and an outlet 7, and forms a cooling container of the liquid-cooled cooler 10.

[0016] The water jacket 5 has a coolant inlet 6 and outlet 7 on its short-side wall. However, the configuration of the cooling container is not particularly limited, and the shapes of the heat sink 2 and water jacket 5, the arrangement of the inlet 6 and outlet 7, etc., can be changed as appropriate.

[0017] As the refrigerant for the liquid-cooled cooler 10, for example, natural refrigerants such as water mixed with ethylene glycol-based antifreeze, water, ammonia, fluorocarbon refrigerants such as Fluorinert, fluorocarbon refrigerants such as HCFC-123 and HFC-134a, alcohol refrigerants such as methanol, and ketone refrigerants such as acetone can be used.

[0018] The operation of the liquid-cooled cooler 10 will be briefly explained using Figure 2. Coolant such as cooling water supplied from the outside flows in through the inlet 6 as indicated by arrow A, passes through the coolant flow path 8 extending in the longitudinal direction of the cooling container, and is discharged from the outlet 7. Heat generated by the electronic component 1 mounted on the base surface 2a is transferred from the base surface 2a to the fins 3 of the fin region 2b, and further transferred to the coolant in contact with the fins 3, thereby cooling the electronic component 1.

[0019] The grooves 4 provided in the heat sink 2 will be explained in detail using Figures 3 and 4. In Figures 3 and 4, arrow A indicates the direction of refrigerant inflow just before it enters the fin region 2b. However, the direction of refrigerant flow is not constant after it enters the fin region 2b. Also, in Figure 4, arrow X indicates the width direction (short side) of the groove 4, and arrow Y indicates the longitudinal direction of the groove 4.

[0020] The fins 3 are prisms and are arranged in a staggered pattern within a rectangular fin region 2b having four end faces. That is, when viewed from any end face of the fin region 2b, the first row of fins 3 and the second row of fins 3 do not overlap, while the first row of fins 3 and the third row of fins 3 overlap.

[0021] The groove 4 is positioned such that its longitudinal direction Y is not parallel to the refrigerant inflow direction A. The refrigerant inflow direction A is parallel to the longitudinal wall surface 2c of the heat sink 2, and the longitudinal direction Y of the groove 4 is at a predetermined angle (approximately 45 degrees) with respect to the longitudinal wall surface 2c of the heat sink 2. Furthermore, the groove 4 is provided to penetrate from one end face to the other end face of the rectangular fin region 2b.

[0022] With this configuration, the longitudinal dimension Y of the groove 4 can be sufficiently secured, which greatly contributes to increasing the heat transfer area of ​​the heat sink 2. The degree of increase in heat transfer area due to the groove 4 varies depending on the width X dimension, longitudinal Y dimension, depth dimension, and shape of the groove 4, but an increase of several percent to 10 percent or more can be expected compared to a configuration without groove 4. Furthermore, some of the refrigerant flowing into the fin region 2b collides with the longitudinal side surface 41 of the groove 4, disrupting the flow. As a result, the refrigerant with a temperature difference in the refrigerant flow path 8 is stirred and mixed, improving the cooling efficiency.

[0023] As mentioned above, since the heat sink 2 is manufactured using a mold, it is desirable that the shape of the groove 4 be simple. In manufacturing methods using molds, mold life is an important indicator, and the more complex and intricate the mold shape, the more stress concentrates in that shape, shortening the mold life. Since the shape of the groove 4 shown in Figures 3 and 4 is simple, adding the groove 4 will hardly shorten the mold life.

[0024] In Embodiment 1, it is sufficient that the longitudinal direction of the grooves is at an angle to the direction of refrigerant inflow, and the shape and arrangement of the grooves 4 shown in Figures 3 and 4 are merely examples. Furthermore, the shape of the fins 3 is not limited to rectangular prisms, but may be cylindrical, hexagonal prisms, etc. Moreover, the number and arrangement of the fins 3 are not limited.

[0025] A modified example of the fin region of the heat sink according to Embodiment 1 will be explained with reference to Figures 5 and 6. In the modified example shown in Figure 5, grooves 4a and 4b, each having longitudinal directions Y1 and Y2 respectively, are arranged in a grid pattern. With this arrangement, the heat transfer area can be increased by approximately 9% compared to the case without grooves, and with the added effect of refrigerant stirring, the heat dissipation performance was improved by approximately 10%.

[0026] Furthermore, in another modified example shown in Figure 6, a cylindrical fin 3a is provided in the fin region 2b. In this case, when the side surface of the fin 3a is curved, the groove 4 is provided with a gap S between it and the base of the fin 3a. This makes it possible to avoid the mold having a complex micro-shape.

[0027] According to the heat sink 2 of Embodiment 1, by having a plurality of grooves 4 in the fin region 2b, the heat transfer area can be increased without increasing the number of parts or the size of the parts or device, thereby improving heat dissipation performance. Furthermore, it is possible to prevent a decrease in fin efficiency, a decrease in refrigerant flow velocity, etc., which can occur when the number of parts is increased or the size of the parts or device is increased.

[0028] Furthermore, because the longitudinal direction Y of the groove 4 is not parallel to the refrigerant inflow direction A, some of the incoming refrigerant collides with the longitudinal side surface 41 of the groove 4, causing it to be agitated and mixed, thereby further improving cooling efficiency. In addition, because the groove 4 has a simple shape, it does not affect the lifespan of the mold used in manufacturing the heat sink 2, and does not lead to an increase in manufacturing costs. Based on these findings, Embodiment 1 makes it possible to realize a heat sink 2 that is low-cost, compact, and has high heat dissipation performance.

[0029] Embodiment 2. Figures 7 and 8 are a perspective view and a plan view showing the fin region of the heat sink according to Embodiment 2. Note that the configuration of the heat sink 2 according to Embodiment 2 is the same as that of the heat sink 2 according to Embodiment 1, except for the grooves 4c provided in the fin region 2b; therefore, a detailed explanation is omitted here.

[0030] The groove 4c of the heat sink 2 according to Embodiment 2 will be explained with reference to Figures 7 and 8. In Figures 7 and 8, arrow A indicates the direction of refrigerant inflow just before it enters the fin region 2b. However, the direction of refrigerant flow is not constant after it enters the fin region 2b. Also, in Figure 8, arrow Y3 indicates the longitudinal direction of the groove 4c.

[0031] The grooves 4c are positioned such that their longitudinal direction Y3 is parallel to the refrigerant inflow direction A. The refrigerant inflow direction A is parallel to the longitudinal wall surface 2c of the heat sink 2, and the longitudinal direction Y3 of the grooves 4c is parallel to the longitudinal wall surface 2c of the heat sink 2. The fins 3 are arranged in a staggered pattern within the rectangular fin region 2b, and the grooves 4c are arranged alternately with the fins 3 in a staggered pattern.

[0032] With this configuration, a portion of the refrigerant flowing into the fin region 2b flows along the longitudinal direction Y3 of the groove 4c, so the flow of refrigerant is not significantly disturbed. In Embodiment 2, it is sufficient that the longitudinal direction of the groove is parallel to the direction of refrigerant inflow, and the shape and arrangement of the groove 4c shown in Figures 7 and 8 are merely examples.

[0033] According to the heat sink 2 of Embodiment 2, by having a plurality of grooves 4c in the fin region 2b, the heat transfer area can be increased without increasing the number of parts or the size of the parts or device, thereby improving heat dissipation performance. Furthermore, it is possible to prevent a decrease in fin efficiency, a decrease in refrigerant flow velocity, etc., which can occur when the number of parts is increased or the size of the parts or device is increased.

[0034] Furthermore, since the longitudinal direction Y3 of the groove 4c coincides with the refrigerant inflow direction A, a portion of the refrigerant flowing into the fin region 2b flows along the longitudinal direction Y3 of the groove 4c, preventing uneven flow of the refrigerant. In addition, because the groove 4c has a simple shape, it does not affect the lifespan of the mold used in manufacturing the heat sink 2 and does not lead to an increase in manufacturing costs. Based on these findings, Embodiment 2 makes it possible to realize a heat sink 2 that is low-cost, compact, and has high heat dissipation performance.

[0035] Embodiment 3. Figures 9 and 10 are a perspective view and a plan view showing the fin region of the heat sink according to Embodiment 3. Note that the configuration of the heat sink 2 according to Embodiment 3 is the same as that of the heat sink 2 according to Embodiment 1, except for the grooves 4c provided in the fin region 2b; therefore, a detailed explanation is omitted here.

[0036] The grooves 4 and 4c of the heat sink 2 according to Embodiment 3 will be explained with reference to Figures 9 and 10. In Figures 9 and 10, arrow A indicates the direction of refrigerant inflow just before it enters the fin region 2b. However, the direction of refrigerant flow is not constant after it enters the fin region 2b. Also, in Figure 10, arrow Y indicates the longitudinal direction of groove 4, and arrow Y3 indicates the longitudinal direction of groove 4c.

[0037] The heat sink 2 according to Embodiment 3 has both the groove 4 (see Figure 4) described in Embodiment 1 and the groove 4c (see Figure 8) described in Embodiment 2. That is, some of the grooves 4 are arranged so that the longitudinal direction Y of the groove 4 is not parallel to the refrigerant inflow direction A, and some of the other grooves 4c are arranged so that the longitudinal direction Y3 of the groove 4c is parallel to the refrigerant inflow direction A. Some of the grooves 4 are provided penetrating from one end face to the other end face of the rectangular fin region 2b.

[0038] With this configuration, the longitudinal dimension Y of some of the grooves 4 can be sufficiently secured, thereby increasing the heat transfer area of ​​the heat sink 2. In addition, some of the refrigerant flowing into the fin region 2b collides with the longitudinal side surface 41 of some of the grooves 4, disturbing the flow, so that the refrigerant with a temperature difference in the refrigerant flow path 8 is stirred and mixed, improving the cooling efficiency. On the other hand, some of the refrigerant flowing into the fin region 2b flows along the longitudinal direction Y3 of some of the other grooves 4c, so the flow is not disturbed significantly.

[0039] In Embodiment 3, it is sufficient that the longitudinal direction of some grooves is at an angle to the refrigerant inflow direction, and the longitudinal direction of other grooves is parallel to the refrigerant inflow direction; the shapes and arrangements of grooves 4 and 4c shown in Figures 9 and 10 are merely examples.

[0040] According to the heat sink 2 of Embodiment 3, by having multiple grooves 4, 4c in the fin region 2b, the heat transfer area can be increased, and the heat dissipation performance can be improved. Furthermore, by providing both grooves 4c that are parallel in the longitudinal direction to the refrigerant inflow direction A and grooves 4 that are not parallel, it is possible to prevent unevenness in the flow of the refrigerant while stirring and mixing the refrigerant to improve the cooling efficiency. In addition, since the grooves 4, 4c have a simple shape, they do not affect the lifespan of the mold when manufacturing the heat sink 2 and do not lead to an increase in manufacturing costs. Based on these findings, Embodiment 3 makes it possible to realize a heat sink 2 that is low-cost, compact, and has high heat dissipation performance.

[0041] Embodiment 4. In Embodiment 4, examples of fin structures and groove structures applicable to the heat sinks according to Embodiments 1 to 3 will be described with reference to Figures 11 to 15. In the example shown in Figure 11, the fin 3 provided in the fin region 2b has a curved surface 31 at the base corner. When manufacturing a heat sink with a mold, stress tends to concentrate at the base corner of the fin 3, making the mold prone to damage. Therefore, by adding a radius (R) to the base corner of the fin 3, the stress can be distributed, extending the lifespan of the mold.

[0042] Furthermore, in the example of the groove structure shown in Figure 12, the groove 4c (see Figures 8 and 10), which is arranged so that the longitudinal direction Y3 is parallel to the refrigerant inflow direction A, has a constant depth dimension D in the cross section parallel to the longitudinal direction Y3. Although not shown, the groove 4c may also have a constant depth dimension in the cross section perpendicular to the longitudinal direction Y3.

[0043] Furthermore, although not shown in the diagram, the grooves 4 (see Figures 4 and 10), which are positioned so that the longitudinal direction Y is not parallel to the refrigerant inflow direction A, have a constant depth dimension in a cross-section parallel or perpendicular to the longitudinal direction Y. By making the depth dimension of grooves 4 and 4c constant in this way, the shape of the mold is simplified, localized stress concentration can be alleviated, and the lifespan of the mold can be extended.

[0044] Furthermore, as shown in Figures 13 to 15, the groove 4c may have different depth dimensions in a cross-section parallel to the longitudinal direction Y3. In the modified example shown in Figure 13, the groove 4c has a greater depth dimension D1 (D1>D) than the groove 4c shown in Figure 12, and has a stepped portion 43 inside, resulting in different depth dimensions D1 and D2 at the bottom surface 42 and the stepped portion 43, respectively. By increasing the depth dimension of the groove 4c or by providing a stepped portion 43 inside, the surface area of ​​the groove 4c is increased, and the heat transfer area of ​​the heat sink is increased.

[0045] Furthermore, the groove 4c may have a sloping bottom surface 42a, as shown in another modified example in Figure 14, or the corners of the bottom surface 42 and the side surface may be curved, as shown in yet another modified example in Figure 15. In this way, the effect on the flow of the refrigerant can be adjusted by sloping the bottom surface 42a of the groove 4c or by adding a radius to the corners. In addition, by adding a radius to the corners of the groove 4c, even if fine dust and other debris flow in along with the refrigerant, it is less likely for the debris to clog the corners, thus preventing a decrease in heat dissipation performance due to clogging.

[0046] Furthermore, although not shown in the figures, the groove 4c may have different depth dimensions in a cross section perpendicular to the longitudinal direction Y3. That is, the groove 4c may have stepped sections, inclined bottom surfaces, or curved corners in a cross section perpendicular to the longitudinal direction Y3. Moreover, the groove 4 may have different depth dimensions in a cross section parallel or perpendicular to the longitudinal direction Y. That is, the groove 4 may have stepped sections, inclined bottom surfaces, or curved corners in a cross section parallel or perpendicular to the longitudinal direction Y.

[0047] In the above embodiments 1 to 4, a heat sink used in a liquid-cooled cooler was described, but the heat sink according to the present invention can also be used in coolers other than liquid-cooled coolers, and the refrigerant may be a gas.

[0048] While this disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but can be applied individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are conceivable within the scope of the technology disclosed herein. These include, for example, modifications, additions, or omissions of at least one component, as well as the extraction of at least one component and its combination with components of other embodiments.

[0049] The various aspects of this disclosure are summarized below as an appendix.

[0050] (Note 1) A heat sink having a fin region on one side with a plurality of pin fins, on the other side to which an electronic component can be attached, and which transfers the heat generated by the electronic component to a coolant flowing through the fin region, The heat sink is characterized in that the fin region has a plurality of grooves provided on one of the surfaces. (Note 2) The heat sink according to Appendix 1, characterized in that the grooves are arranged such that their longitudinal direction is not parallel to the inflow direction of the refrigerant immediately before it enters the fin region. (Note 3) The heat sink according to Appendix 1 or Appendix 2, characterized in that the pin fins are arranged in a staggered pattern within the rectangular fin region, and the grooves are provided penetrating from one end face to the other end face of the fin region. (Note 4) The heat sink according to any one of the appendices 1 to 3, characterized in that the grooves are arranged in a grid pattern. (Note 5) The heat sink according to Appendix 1, characterized in that the groove is arranged such that its longitudinal direction is parallel to the inflow direction of the refrigerant immediately before it enters the fin region. (Note 6) The heat sink according to Appendix 5, characterized in that the pin fins are arranged in a staggered pattern in the fin region, and the grooves are arranged alternately with the pin fins in a staggered pattern. (Note 7) The heat sink according to Appendix 1, characterized in that some of the grooves are arranged such that their longitudinal direction is not parallel to the inflow direction of the refrigerant immediately before it enters the fin region, and other grooves are arranged such that their longitudinal direction is parallel to the inflow direction of the refrigerant immediately before it enters the fin region. (Note 8) The heat sink according to any one of the appendices 1 to 7, characterized in that the pin fins are cylindrical and the grooves are provided at a distance from the base of the pin fins. (Note 9) The heat sink according to any one of the appendices 1 to 8, characterized in that the pin fins have curved corners at their bases. (Note 10) The heat sink according to any one of the appendices 1 to 9, characterized in that the groove has a certain depth dimension. (Note 11) The heat sink according to any one of the appendices 1 to 9, characterized in that the groove has different depth dimensions in a cross section parallel to the longitudinal direction of the groove. (Note 12) The heat sink according to any one of the appendices 1 to 9, characterized in that the groove has different depth dimensions in a cross section perpendicular to the longitudinal direction of the groove. (Note 13) The heat sink according to Appendix 11 or Appendix 12, characterized in that the groove has a step inside. (Note 14) The heat sink according to Appendix 11 or Appendix 12, characterized in that the groove has a sloping bottom surface. (Note 15) The heat sink according to Appendix 11 or Appendix 12, characterized in that the groove has curved corners on the bottom and side surfaces. (Note 16) A heat sink according to any one of the appendices 1 to 15, characterized in that it is joined to a water jacket having an inlet and outlet for the refrigerant, forming a cooling container for a liquid-cooled cooler. [Industrial applicability]

[0051] This invention can be used as a heat sink that constitutes a cooler. [Explanation of Symbols]

[0052] 1 Electronic component, 2 Heat sink, 2a Base surface, 2b Fin area, 2c Longitudinal wall surface, 3, 3a Fins, 31, 44 Curved surface, 4, 4a, 4b, 4c Groove, 5 Water jacket, 6 Inlet, 7 Outlet, 8 Coolant flow path, 10 Liquid-cooled cooler, 20 Power converter, 41 Longitudinal side surface, 42, 42a Bottom surface, 43 Stepped section

Claims

1. A heat sink having a fin region on one side with a plurality of pin fins, on the other side to which an electronic component can be attached, and which transfers the heat generated by the electronic component to a coolant flowing through the fin region, The fin region has a plurality of grooves provided on one of its surfaces, The heat sink is characterized in that the groove has different depth dimensions in a cross-section parallel to the longitudinal direction of the groove.

2. The heat sink according to claim 1, characterized in that the grooves are arranged such that the longitudinal direction of the grooves is not parallel to the inflow direction of the refrigerant immediately before it enters the fin region.

3. The heat sink according to claim 2, characterized in that the pin fins are arranged in a staggered pattern within the rectangular fin region, and the grooves are provided penetrating from one end face to the other end face of the fin region.

4. The heat sink according to any one of claims 1 to 3, characterized in that the grooves are arranged in a grid pattern.

5. The heat sink according to claim 1, characterized in that the groove is arranged such that its longitudinal direction is parallel to the inflow direction of the refrigerant immediately before it enters the fin region.

6. The heat sink according to claim 5, characterized in that the pin fins are arranged in a staggered pattern in the fin region, and the grooves are arranged alternately with the pin fins in a staggered pattern.

7. The heat sink according to claim 1, characterized in that some of the grooves are arranged such that their longitudinal direction is not parallel to the inflow direction of the refrigerant immediately before it enters the fin region, and other grooves are arranged such that their longitudinal direction is parallel to the inflow direction of the refrigerant immediately before it enters the fin region.

8. The heat sink according to claim 1, characterized in that the pin fins are cylindrical and the grooves are provided at a distance from the base of the pin fins.

9. The heat sink according to claim 1, characterized in that the pin fins have curved corners at their bases.

10. The heat sink according to claim 1, characterized in that the groove has a constant depth dimension in a cross-section perpendicular to the longitudinal direction of the groove.

11. The heat sink according to claim 1, characterized in that it is joined to a water jacket having a refrigerant inlet and outlet, forming a cooling container for a liquid-cooled cooler.

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