Heat sink and cooler

Abstract

To provide a heat sink or other devices that can reduce pressure loss.SOLUTION: A heat sink 11 includes a flat plate-shaped portion 111 and a plurality of fins 112 protruding from the flat plate-shaped portion 111 in a direction intersecting the plate surface of the flat plate-shaped portion 111. The fin 112 has a groove 114 formed in the center of the tip, which is a portion away from the flat plate-shaped portion 111, which is recessed from the end face 113 toward the flat plate-shaped portion 111.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a heat sink and a cooler. [Background technology]

[0002] Conventionally, semiconductor devices capable of improving the cooling performance have been proposed. For example, the semiconductor device described in Patent Document 1 includes a semiconductor module having a flat heat spreader, and a heat sink joined to the heat spreader by metal bonding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2023-70910 Summary of the Invention [Problem to be solved by the invention]

[0004] 2. Description of the Related Art Cooling devices that cool objects to be cooled, such as semiconductor modules, and heat sinks used in cooling devices are required to reduce pressure loss while maintaining cooling performance. An object of the present invention is to provide a heat sink or the like capable of reducing pressure loss. [Means for solving the problem]

[0005] The present invention, which was completed with this objective in mind, is a heat sink comprising a flat plate-like portion and a plurality of fins protruding from the flat plate-like portion in a direction intersecting the plate surface of the flat plate-like portion, wherein a groove is formed in the center of the tip portion, which is away from the flat plate-like portion, and which is recessed from the end face toward the flat plate-like portion. Here, the cross-sectional shape of the fin may be rectangular, and one corner of the rectangle may face upstream in the flow direction of the cooling liquid, while another corner located on the same diagonal as the one corner may face downstream in the flow direction. Moreover, the groove may be formed in the same direction as the flow direction. Alternatively, the groove may be formed in a direction inclined with respect to the flow direction. Alternatively, one groove may be formed in a direction inclined with respect to the flow direction, and another groove may be formed so as to intersect with the inclined direction. The depth of the groove may be 10 to 60% of the size of the fin in the protruding direction. The fin may have a cross-sectional shape of a rectangle with two diagonals intersecting at right angles, and the width of the groove may be 10 to 60% of the width of two parallel faces of the fin. Moreover, the grooves formed in the plurality of fins may all have the same width. Furthermore, the width of the grooves formed in the plurality of fins may be the same as the gap between adjacent fins. Viewed from another perspective, the present invention is a cooler comprising the above-described heat sink and a housing that surrounds the multiple fins of the heat sink so that a cooling liquid flows between the multiple fins. Effect of the Invention

[0006] According to the present invention, it is possible to provide a heat sink or the like capable of reducing pressure loss. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing an example of an external appearance of a semiconductor device according to an embodiment; [Diagram 2] 1 is an example of an exploded view of components constituting a semiconductor device according to an embodiment; [Diagram 3] 1 is a diagram showing an example of a cross section of a semiconductor device according to an embodiment; [Figure 4] FIG. 2 is a diagram showing an example of a state before two heat sinks and a semiconductor module are joined together. [Diagram 5] 1A is an example of a view of a heat sink seen from above, and FIG. 1B is an example of a cross section taken along line Vb-Vb in FIG. [Figure 6] 6 is an example of a view of a fin according to a first modified example viewed from above. [Figure 7] 13 is an example of a view of a fin according to a second modified example viewed from above. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. <Embodiment Mode> FIG. 1 is a diagram showing an example of the appearance of a semiconductor device 1 according to an embodiment. FIG. 2 is an example of an exploded view of components constituting the semiconductor device 1 according to the embodiment. 3 is a diagram showing an example of a cross section of the semiconductor device 1 according to the embodiment, taken along line III-III of FIG. FIG. 4 is a diagram showing an example of a state before the heat sink 11 and the heat sink 21 are joined to the semiconductor module 100. As shown in FIG.

[0009] A semiconductor device 1 according to the embodiment includes a semiconductor module 100 having a power semiconductor element 101 and a cooling device 2 that cools the semiconductor module 100. 1, the semiconductor device 1 is mounted on, for example, an automobile, with the semiconductor module 100 sandwiched between a first cooler 10 and a second cooler 20 of the cooling device 2, which will be described later. Hereinafter, the direction in which the first cooler 10 and the second cooler 20 are stacked may be referred to as the "vertical direction". In addition, in the rectangular first cooler 10 and the second cooler 20, which are rectangular, the longitudinal direction perpendicular to the vertical direction may be referred to as the "longitudinal direction", and the lateral direction of the rectangular shape may be referred to as the "lateral direction".

[0010] The semiconductor module 100 is a card-type power module, and includes a power semiconductor element 101 mounted on a ceramic insulating substrate (not shown), and flat heat spreaders 102 provided on both sides (upper and lower) of the power semiconductor element 101. The heat spreader 102 is made of at least one of copper and an aluminum material such as aluminum or an aluminum alloy.

[0011] The cooling device 2 includes a first cooler 10 and a second cooler 20 that are coolers capable of circulating a cooling liquid therethrough, and an interposition member 30 that is interposed between the first cooler 10 and the second cooler 20. The cooling device 2 also includes a connecting member 40 that is connected to the first cooler 10 and the second cooler 20, and a support member 50 that supports the first cooler 10 and the second cooler 20 via the connecting member 40.

[0012] (1st cooler 10) The first cooler 10 includes a heat sink 11 having fins 112, a case 12 that houses the fins 112 of the heat sink 11 and forms a space through which a coolant flows, and a cover 13 that covers an opening of the case 12. The case 12 and the cover 13 form a housing 14 that surrounds the multiple fins 112 of the heat sink 11 so that the coolant flows between the multiple fins 112.

[0013] The heat sink 11 has a flat plate-shaped portion 111 and a plurality of fins 112 protruding from the flat plate-shaped portion 111 in a direction perpendicular to the plate surface. The flat plate portion 111 has a first surface 111a which is the surface on which the fins 112 are formed, and a flat second surface 111b which is the surface on the side on which the fins 112 are not formed. The fins 112 are formed in a partial area near the center of the first surface 111a, and the outside of the area on the first surface 111a where the fins 112 are formed is a flat surface. Hereinafter, this flat surface on the outside of the area where the fins 112 are formed may be referred to as an outer surface 111c. The fins 112 will be described in more detail below.

[0014] The heat sink 11 may be formed by cutting, for example. The heat sink 11 may be formed from at least one of copper and aluminum. The aluminum material may be A1000 series pure aluminum such as A1100.

[0015] The heat sink 11 is integrated with the semiconductor module 100 by metal fusion bonding of the second surface 111b of the flat plate portion 111 to the heat spreader 102 of the semiconductor module 100. The metal fusion bonding is performed by soldering or copper sintering.

[0016] Case 12 is concave and has a flat bottom 121, a side 122 extending from the outer periphery of bottom 121 in a direction perpendicular to bottom 121, and a flange 123 protruding outward from the tip of side 122 in a direction parallel to bottom 121. Bottom 121 and side 122 form a recess, and flange 123 is formed around this recess. The material of case 12 can be, for example, aluminum or copper.

[0017] Cover 13 is flat and has an outer shape that is the same as the outer periphery of flange 123 of case 12. Cover 13 and flange 123 of case 12 are joined together, whereby cover 13 closes the opening of the recess of case 12. Examples of a method for joining cover 13 and case 12 include brazing and laser welding.

[0018] A circular first through hole 131 is formed at one end in the longitudinal direction of the cover 13, and a circular second through hole 132 is formed at the other end in the longitudinal direction. In addition, the cover 13 is formed between the first through hole 131 and the second through hole 132 with the same number of rectangular third through holes 133 as the number of the heat sink 11 (three in this embodiment) for passing the fins 112 of the heat sink 11 therethrough.

[0019] The cover 13 is joined to the outer side surface 111c around the fin 112 of the flat portion 111 of the heat sink 11, with the fin 112 of the heat sink 11 passing through the third through hole 133. The method for joining the cover 13 and the heat sink 11 can be, for example, brazing or laser welding. The material of the cover 13 can be, for example, aluminum or copper.

[0020] (2nd cooler 20) The second cooler 20 has a heat sink 21 that is the same as the heat sink 11 of the first cooler 10, and a housing 24 that corresponds to the housing 14. The housing 24 has a case 22 that corresponds to the case 12 of the first cooler 10, and a cover 23 that is the same as the cover 13 of the first cooler 10. In other words, the second cooler 20 has approximately the same shape as the first cooler 10, except that a first through hole 241 and a second through hole 242, which will be described later, are formed. The second cooler 20 is disposed symmetrically to the first cooler 10 with respect to the semiconductor module 100.

[0021] More specifically, the heat sink 21 has a flat plate portion 211 that is the same as the flat plate portion 111 of the heat sink 11, and fins 212 that are the same as the fins 112 of the heat sink 11. The flat plate portion 211 has a first surface 211a, a second surface 211b, and an outer surface 211c that are the same as the first surface 111a, the second surface 111b, and the outer surface 111c of the flat plate portion 111, respectively.

[0022] Case 22 has a bottom 221, sides 222 and a flange 223 which are identical to bottom 121, sides 122 and flange 123 of case 12, respectively. Case 22 differs from case 12 in that a first circular through hole 241 is formed at one end in the longitudinal direction of bottom 221, and a second circular through hole 242 is formed at the other end in the longitudinal direction.

[0023] The cover 23 has a first through hole 231, a second through hole 232, and a third through hole 233 that are identical to the first through hole 131, the second through hole 132, and the third through hole 133 formed in the cover 13, respectively.

[0024] (Interposed member 30) The intervening member 30 is a cylindrical member. The inner diameter of the intervening member 30 is approximately the same as the diameters of the first through hole 131 and the second through hole 132 formed in the cover 13. The intervening member 30 has an upper portion joined to the cover 13 and a lower portion joined to the cover 23. The joining method can be, for example, laser welding or brazing. The material of the interposition member 30 can be, for example, aluminum or copper.

[0025] (Connecting member 40) The connecting member 40 is an elliptical cylindrical member whose minor axis direction is the longitudinal direction of the case 12 and whose major axis direction is the lateral direction of the case 12. A circular first through hole 41 is formed in the center of the connecting member 40. The first through hole 41 has the same shape as the first through hole 241 and the second through hole 242 of the case 22 of the second cooler 20. In addition, the connecting member 40 has second through holes 42 formed on both outer sides of the first through hole 41 in the major axis direction. The material of the connecting member 40 can be, for example, aluminum or copper.

[0026] (Support member 50) The support member 50 has a first space 51 recessed from the top surface at one end in the longitudinal direction, and a second space 52 recessed from the top surface at the other end in the longitudinal direction. An opening 51a on the top surface side of the first space 51 has the same shape as the first through hole 41 of the connecting member 40. An opening 52a on the top surface side of the second space 52 has the same shape as the first through hole 41 of the connecting member 40. A groove 51b into which an O-ring 55 is fitted is formed around the opening 51a of the support member 50. A groove 52b into which an O-ring 56 is fitted is formed around the opening 52a of the support member 50. In addition, the support member 50 has female threads 51c formed on both outer sides of the groove 51b in the long axis direction. In addition, the support member 50 has female threads 52c formed on both outer sides of the groove 52b in the long axis direction.

[0027] A communication hole is formed in the support member 50, connecting the first space 51 with the outside in a direction perpendicular to the up-down direction (the short side direction in Figs. 1 and 2), and a first joint 53 is fitted into the communication hole. Also, a communication hole is formed in the support member 50, connecting the second space 52 with the outside in a direction perpendicular to the up-down direction, and a second joint 54 is fitted into the communication hole. The material of the support member 50 can be, for example, aluminum or copper.

[0028] (Function of Semiconductor Device 1) In the semiconductor device 1 configured as described above, the cooling liquid that has flowed into the first space 51 from the first joint 53 of the support member 50 passes through the opening 51a and the first through hole 241 formed at one end in the longitudinal direction of the case 22 of the second cooler 20, and then flows into the inside of the second cooler 20. The cooling liquid that has flowed into the inside of the second cooler 20 then advances in the longitudinal direction through between the multiple fins 212 of the heat sink 21 and between the fins 212 and the side part 222 of the case 22, and flows out of the second cooler 20 through the second through hole 242 formed at the other end in the longitudinal direction of the case 22.

[0029] A part of the cooling liquid that has flowed into the second cooler 20 through the first through hole 241 flows out of the second cooler 20 through the first through hole 231 of the cover 23, and flows into the first cooler 10 through the inside of the intervening member 30 and the first through hole 131 of the cover 13 of the first cooler 10. The cooling liquid that has flowed into the first cooler 10 advances in the longitudinal direction through the spaces between the fins 112 of the heat sink 11 and between the fins 112 and the side portion 122 of the case 12, and flows out of the first cooler 10 through the second through hole 132 formed at the other end of the cover 13 in the longitudinal direction.

[0030] The cooling liquid that flows out of the first cooler 10 flows into the inside of the second cooler 20 through the inside of the intervening member 30 and the second through hole 232 of the cover 23 of the second cooler 20, and then flows out of the second cooler 20 through the second through hole 242 formed at the other longitudinal end of the case 22. The cooling liquid that has flowed out of the second cooler 20 enters the second space 52 through the opening 52a formed in the support member 50, and flows out from the second joint .

[0031] In this manner, while the cooling liquid circulates through the inside of the first cooler 10 and the inside of the second cooler 20, the semiconductor module 100 arranged between the first cooler 10 and the second cooler 20 is cooled. In the first cooler 10 of the semiconductor device 1, the coolant flows from the first through hole 131 to the second through hole 132 of the cover 13. Hereinafter, the longitudinal direction from the first through hole 131 to the second through hole 132 may be referred to as the "flow direction" of the coolant.

[0032] (Fins 112 of heat sink 11) Fig. 5(a) is an example of a view of the heat sink 11 as seen from above. Fig. 5(b) is an example of a cross section taken along line Vb-Vb in Fig. 5(a). As shown in FIG. 5(a), the shape of fin 112 when cut along a plane perpendicular to the protruding direction (hereinafter sometimes referred to as the "cross-sectional shape") is a square, with a first corner 116 as an example of one corner of the square facing upstream in the flow direction of the coolant, and a second corner 117 (another corner) located on the same diagonal as first corner 116 facing downstream in the flow direction.

[0033] The fin 112 has a groove 114 recessed from the end surface 113 toward the flat plate portion 111 at the tip portion, which is a portion away from the flat plate portion 111. The groove 114 is formed in an "X" shape. That is, the groove 114 passes through an intersection point where a diagonal line connecting the first corner portion 116 and the second corner portion 117 intersects with a diagonal line perpendicular to the diagonal line, and two grooves 114 are formed in directions that form 45 degrees in each of the clockwise and counterclockwise directions in FIG. 5(a) with respect to the flow direction. In other words, one groove 114 is formed in a direction inclined with respect to the flow direction, and another groove 114 is formed so as to intersect with the inclined direction. The groove 114 is formed so as to penetrate the tip portion of the fin 112 in a direction parallel to the flat plate portion 111. The width W1 of the grooves 114 formed in each of the multiple fins 112 is the same. Moreover, the width W1 of the groove 114 is the same as the size of the gap G between adjacent fins 112. Moreover, as shown in Fig. 5(b), the depth h of the groove 114 is 10% or more of the size L of the fin 112 in the protruding direction.

[0034] As described above, the heat sink 11 includes the flat plate-shaped portion 111 and the multiple fins 112 protruding from the flat plate-shaped portion 111 in a direction intersecting the plate surface of the flat plate-shaped portion 111. The fins 112 have grooves 114 recessed from the end surface 113 toward the flat plate-shaped portion 111 in the center of the tip portion, which is a portion away from the flat plate-shaped portion 111.

[0035] In the heat sink 11 configured as described above, the grooves 114 are formed in the fins 112, and therefore the flow path area at the tip of the fins 112 is larger than that of a configuration in which the grooves 114 are not formed in the fins 112, and the pressure loss is smaller. In addition, the flow path area is larger on the tip side of the fins 112, not on the flat plate portion 111 side. In other words, the flow path area is larger on the tip side away from the semiconductor module 100 than on the flat plate portion 111 side to which the semiconductor module 100 is joined. Therefore, even if the grooves 114 are formed in the tip of the fins 112, the performance of cooling the semiconductor module 100 is prevented from decreasing compared to a configuration in which the grooves 114 are not formed in the fins 112.

[0036] As a result of intensive research, the present inventors have found that the groove depth h is preferably 10% or more and 60% or less of the size L of the fin 112 in the protruding direction. If the groove depth h is less than 10% of the size L of the fin 112 in the protruding direction, it is insufficient to reduce pressure loss. On the other hand, if the groove depth h exceeds 60% of the size L of the fin 112 in the protruding direction, the performance of cooling the semiconductor module 100 decreases.

[0037] In the heat sink 11, the cross-sectional shape of the fins 112 is a rectangle, and a first corner 116 (one example of one corner) of the rectangle faces the upstream side in the flow direction of the coolant, while a second corner 117 (another example of a corner) located on the same diagonal line as the first corner 116 faces the downstream side in the flow direction. Therefore, the flow direction of the coolant can be changed at the first corner 116, and the coolant can be divided evenly. As a result, the coolant can be distributed to both ends of the heat sink 11 in a direction perpendicular to the flow direction (the up-down direction in FIG. 5(a)). Although FIG. 5(a) shows a square as an example of the quadrangle, the cross-sectional shape of the fin 112 may be a rhombus or a rectangle.

[0038] In addition, in the heat sink 11, the grooves 114 are formed in a direction inclined with respect to the flow direction and two grooves 114 are formed to intersect. Therefore, the flow direction of the coolant can be changed at the intersection of the two grooves 114, and the coolant can be divided more uniformly. In addition, the surface area of ​​the fins 112 can be increased, thereby improving the cooling performance.

[0039] As a result of intensive research, the present inventors have found that the width W1 of groove 114 is preferably 10 to 60% of the two parallel plane width W0 of fin 112. If the width W1 of groove 114 is less than 10% of the two parallel plane width W0, the coolant does not easily flow into groove 114, which is insufficient for reducing pressure loss. On the other hand, if the width W1 of groove 114 exceeds 60% of the two parallel plane width W0, the surface area of ​​fin 112 becomes small, and the performance of cooling semiconductor module 100 decreases.

[0040] Furthermore, in the heat sink 11, the grooves 114 formed in the fins 112 all have the same width W1. Therefore, only one type of tool is required for cutting and forming the grooves 114, so that the cost for manufacturing the tool and the time for manufacturing the heat sink 11 can be reduced.

[0041] Furthermore, in heat sink 11, width W1 of grooves 114 formed in multiple fins 112 is the same as the size of gap G between adjacent fins 112. Therefore, the same tool can be used to cut out fins 112 having a square cross section from a rectangular block and to cut and form grooves 114, thereby reducing the cost of manufacturing the tools and the time required to manufacture heat sink 11.

[0042] <Modifications of fins> Modifications of the fins 112 will be described below. FIG. 6 is an example of a view of the fin 300 according to the first modified example seen from above. Fin 300 according to the first modification example differs from fin 112 in that only one groove 114 is formed in fin 112. Fins 300 and 112 that have the same functions are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

[0043] More specifically, in the fin 300, one groove 114 is formed that passes through the intersection of a diagonal line connecting the first corner 116 and the second corner 117 and a diagonal line perpendicular to the diagonal line, and that forms an angle of 45 degrees counterclockwise in Fig. 6 with respect to the flow direction. The groove 114 is formed so as to penetrate the tip of the fin 300 in a direction parallel to the flat plate portion 111. The width W1 of the groove 114 formed in each of the multiple fins 300 is all the same, and the width W1 of the groove 114 is the same as the size of the gap G between adjacent fins 300.

[0044] As described above, in the fin 300 according to the first modification, one groove 114 is formed in a direction inclined with respect to the flow direction. Even if there is one groove 114, the flow path area at the tip of the fin 300 is larger than in a configuration in which the fin 300 does not have the groove 114 formed therein, and therefore the pressure loss is smaller. In addition, since the flow path area is larger on the tip side of the fin 300, not on the flat plate portion 111 side, even if the groove 114 is formed at the tip of the fin 300, the performance of cooling the semiconductor module 100 is prevented from decreasing compared to a configuration in which the fin 300 does not have the groove 114 formed therein. The direction of the groove 114 may be at an angle of 45 degrees clockwise in FIG. 6 with respect to the flow direction.

[0045] FIG. 7 is an example of a view of a fin 400 according to the second modified example seen from above. Fin 400 according to the second modification has grooves 414 that correspond to grooves 114 and that face in a different direction from fin 300 according to the first modification. Fins 400 and 300 that have the same functions are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

[0046] More specifically, one groove 414 is formed in the fin 400 in the flow direction, in other words, in the direction of a diagonal line connecting the first corner 116 and the second corner 117. Moreover, groove 414 is formed so as to penetrate the tip end of fin 400 in a direction parallel to flat plate portion 111. All of grooves 414 formed in each of the multiple fins 400 have the same width W1, and width W1 of groove 414 is the same as the size of gap G between adjacent fins 400.

[0047] As described above, in the fin 400 according to the second modification, one groove 414 is formed in the same direction as the flow direction. Since the groove 414 is in the same direction as the flow direction, the flow in the flow direction is promoted and pressure loss is reduced. In addition, since the flow path area is larger on the tip end side of the fin 400 and not on the flat plate portion 111 side, even if the groove 414 is formed on the tip end of the fin 400, the performance of cooling the semiconductor module 100 is prevented from decreasing compared to a configuration in which the groove 414 is not formed in the fin 400.

[0048] It should be noted that the width W1 of the groove 414 does not have to be the same as the size of the gap G between adjacent fins 400. By adjusting the width W1 of the groove 414, it becomes possible to adjust the pressure loss. [Explanation of symbols]

[0049] REFERENCE SIGNS LIST 1...semiconductor device, 2...cooling device, 10...first cooler, 11, 21...heat sink, 12, 22...case, 13, 23...cover, 14, 24...housing, 20...second cooler, 30...intervening member, 40...connecting member, 50...support member, 100...semiconductor module, 101...power semiconductor element, 111, 211...flat plate portion, 112, 212, 300, 400...fins, 113...end surface, 114, 414...groove, 116...first corner portion, 117...second corner portion

Claims

1. A flat plate-shaped portion, A plurality of fins protruding from the flat plate portion in a direction intersecting a plate surface of the flat plate portion; Equipped with The fin has a groove formed in a central portion of the tip portion, the groove being recessed from the end surface toward the flat portion, the central portion being away from the flat portion. heat sink.

2. The cross-sectional shape of the fin is a rectangle, and one corner of the rectangle faces the upstream side in the flow direction of the cooling liquid, and another corner located on the same diagonal line as the one corner faces the downstream side in the flow direction. The heat sink of claim 1 .

3. The groove is formed in the same direction as the flow direction. The heat sink of claim 2 .

4. The groove is formed in a direction inclined with respect to the flow direction. The heat sink of claim 2 .

5. The groove is formed in a direction inclined with respect to the flow direction, and another groove is formed so as to intersect with the inclined direction. The heat sink of claim 2 .

6. The depth of the groove is 10 to 60% of the size of the fin in the protruding direction. The heat sink of claim 1 .

7. The fin has a cross-sectional shape of a rectangle with two diagonals intersecting at right angles, The width of the groove is 10 to 60% of the parallel two-face width of the fin. The heat sink of claim 2 .

8. The widths of the grooves formed in the plurality of fins are all the same. The heat sink of claim 1 .

9. The width of the grooves formed in the plurality of fins is equal to the gap between adjacent fins. The heat sink of claim 1 .

10. A heat sink according to any one of claims 1 to 9; a housing that encloses the fins of the heat sink so that a cooling liquid flows between the fins; and A cooling device comprising:

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