A cooling device with a heat sink for at least one microchip

Abstract

A heat sink for at least one microchip, characterized in that it has a thermally conductive heat sink with a channel structure for a cooling fluid with a supply and a return, and on each of two opposing outer faces of the heat sink, a cooling plate thermally and mechanically coupled to the channel structure. Furthermore, a corresponding cooling device is described.

Description

[Technical field]

[0001] The invention is based on a heat sink, often also called a "cold plate", for at least one electronic component, which comprises a thermally conductive heat sink having a channel structure for a cooling fluid with a supply and a return. Such a heat sink is described in US 10,485,143 B2. A heat sink having the features of the preamble of claim 1 is disclosed in US 2009 / 0114373 A1. Similar devices are also described in JP 4027353 B2 and EP 2386194 B1. Furthermore, similar cooling elements are disclosed in US 2010 / 0084120 A1 and DE 21 2012 000 223 A1. [Background technology]

[0002] As the computing power of many electronic components, e.g. IT components such as microchips (CPU, GPU, etc.), AC converters, etc., increases, so do their power losses and the associated heat generation. Progressive further developments, for example in the field of microchip technology, allow in some cases to achieve powers of more than 400 watts per chip. Due to the increased power density, known air-cooled heat sinks and heat sinks are no longer suitable to sufficiently dissipate the resulting power losses, taking into account the limited space conditions, e.g. in a server housing. However, new cooling techniques, such as "direct chip cooling", allow microchips to be effectively cooled. On the other hand, these techniques are significantly more complex than known heat sinks and are relatively less resistant to failures. Heat pipes known from the prior art, based on copper tubes and aluminum laminates, also have a limited cooling capacity. As a rule, an effort is made to maximize the performance of electronic components and at the same time provide products at the lowest possible cost. One possibility to reduce the infrastructure and its costs is to make better use of the available space on the servers and increase their computing power without increasing the available volume. This also makes it possible to upgrade existing data centers with higher computing power in cases where there are certain space requirements. Summary of the Invention [Problem to be solved by the invention]

[0003] SUMMARY OF THE DISCLOSURE It is therefore an object of the present invention to further develop a heat sink of the type described in the introduction in such a way that it provides high cooling power with low space requirements. [Means for solving the problem]

[0004] This object is achieved by a heat sink having the features of claim 1. Independent claim 13 relates to a corresponding cooling device.

[0005] In the case of a heat sink, it therefore comprises, on both opposing outer faces, a respective cooling plate thermally coupled to the channel structure. Thus, unlike heat sinks known from the prior art, the invention is based on the idea of ​​configuring the heat sink in the form of a plate, i.e. a planar shape, the dimension perpendicular to the opposing outer faces of which is small, in order to provide as large an area as possible for conductive heat transfer from the electronic component requiring cooling to the heat sink.

[0006] As a result, not only one of the two opposing outer surfaces of the heat sink is used for cooling the electronic components requiring cooling, but rather both sides are preferably used for cooling at least one electronic component.The heat sink, in particular the thermally conductive heat sink, can be configured symmetrically with respect to the two outer surfaces carrying the cooling plates, so that the heat sink has identical cooling plates for thermal coupling of the electronic components requiring cooling in two positions rotated 180° relative to each other.

[0007] If the channel structure of the heat sink is thermally coupled to both cooling plates arranged on the opposite outer surfaces, the cooling power provided by the heat sink is equally provided by both cooling plates. Therefore, the heat sink can also be configured symmetrically with respect to the channel structure with respect to the two cooling plates. For example, the heat sink can be completely symmetric with respect to its central plane, which runs parallel to the two cooling plates. The forward and return flows can be arranged at the end sides of the heat sink, which are oriented perpendicular to the cooling plates so as not to constitute an obstruction structure with respect to the mounting of electronic components requiring cooling on the opposite cooling plate.

[0008] When cooling fluids are described in this application, they may be single-phase cooling fluids, but also multi-phase cooling fluids, in particular two-phase cooling fluids having a liquid phase and a gas phase, for example cooling fluids having a gas phase.

[0009] In order to provide a particularly good thermal conductivity of the heat sink and thereby distribute the cooling power as evenly as possible over the entire volume of the heat sink or over the area of ​​the at least one cooling plate, the heat sink, in particular at least the at least one cooling plate and the channel structure, can be constructed in one piece by additive manufacturing methods, for example build-up welding.

[0010] The channel structure can be guided in a serpentine manner in the heat sink, parallel to at least one or both cooling plates. In order to maximize the length of the channel structure, the channel structure can have at least two channel sections which pass substantially parallel to one another in the heat sink and are preferably packed as closely as possible, and at the opposite ends of the heat sink, at least one fluid transition can be provided between the at least two channel sections, in which at least two consecutive parallel channel sections are connected to one another via a deflection of 180° to form the serpentine channel structure.

[0011] The channel structure preferably consists of a plurality of channel sections connected to one another via a fluid transition, at least one of the channel sections at least partially consisting of a plurality of sub-channels fluidically separated from one another along the channel section. The sub-channels can in particular run parallel to one another. The sub-channels can be fluidically separated from one another via a partition wall. The partition walls can be thermally coupled, respectively, on opposing sides to at least one or both of two opposing cooling plates, and are preferably formed integrally with one or more cooling plates in order to achieve optimal heat transfer between the at least one cooling plate and the fluid flowing in the sub-channel. The partition wall itself therefore preferably consists of a thermally conductive material. If a thermal transition is provided between the partition wall and the at least one cooling plate, the partition wall can contribute to the heat exchange to the fluid flowing in the sub-channel.

[0012] The separated sub-channels can each be thermally coupled to both cooling plates, and thus can extend directly to the opposing cooling plate such that fluid flowing through the sub-channel is in thermal contact with the cooling plate.

[0013] The sub-channel may extend at least partially, preferably at least entirely, over the entire distance between the two cooling plates.

[0014] A channel section with a plurality of sub-channels fluidically separated from one another along the channel section can open directly into the fluidic transition section with all the sub-channels. Thus, there is no particular need for the sub-channels to be joined to one another before they open into the fluidic transition section. The fluid flows separated from one another by the sub-channels can only be joined at the fluidic transition section. Thus, all the sub-channels of the channel section feeding the fluidic transition section and also all the sub-channels of the channel section feeding from the fluidic transition section can open into the fluidic transition section in the flow direction. The fluidic transition section can be configured as a recess close to the end side of the heat sink, into which all the sub-channels of the aforementioned feeding and feeding channel sections open.

[0015] The channel structure may have a plurality of channel sections, at least in part consisting of a plurality of subchannels fluidly separated from one another along the respective channel sections. The channel sections preferably have a different number of subchannels. Particularly preferably, a second channel section following a first one of the channel sections in the flow direction from the supply to the return has a greater number of subchannels than the first one. The increase in the number of channels in the respective channel sections is set to compensate for the increase in the volume of the cooling medium due to evaporation of the liquid. The more liquid that passes into the gaseous state, the more volume is required to keep the pressure loss in the channels substantially constant. When using a liquid medium such as water, the increase in the number of channels in the respective channel sections can be omitted.

[0016] In particular, the sum of the channel cross-sectional areas of the sub-channels of the first channel section can be smaller than the sum of the channel cross-sectional areas of the sub-channels of the second channel section. In this case, it is possible to aim to keep the velocity of the cooling fluid, and therefore the pressure loss, constant. In the case of a cooling fluid consisting essentially of a liquid phase, the flow velocity of the second channel section is reduced relative to the first channel section, which, in combination with the resulting increased channel wall surface area due to the increasing number of sub-channels, still provides a sufficient or constant cooling power even when the temperature of the cooling fluid increases relative to the first channel section due to the increased residence time of the cooling fluid in the second channel section. The increasing number of sub-channels and the increasing flow cross-sectional area of ​​the channel section relative to the preceding channel section in the flow direction can also serve to compensate for the increase in the volume of the refrigerant used, when it is a two-phase refrigerant, which occupies a correspondingly larger volume with an increased rate of transition from liquid to gas phase when passing through a heat sink and increasing heat transfer to the refrigerant.

[0017] The channel sections may have an increasing number of subchannels per channel section in the direction of flow from the supply to the return.

[0018] The sub-channels of all channel sections can run parallel to one another, the sub-channels having a channel cross-section which is preferably constant, particularly preferably substantially identical or identical, for all sub-channels.

[0019] The channel section which opens into the return port and thus terminates in the flow direction can have a channel width which corresponds to at least twice, preferably at least three times, particularly preferably at least four times the width of the channel section which opens into the feed port.

[0020] The return inlet can have a cross-sectional area that is at least twice as large as the supply inlet, preferably at least three times as large, particularly preferably at least four times as large, so that optimal drainage of the heated fluid from the heat sink is ensured even at low fluid pressures and low flow rates.

[0021] According to another aspect, a cooling device is described that comprises at least one heat sink of the above-mentioned type and at least two electronic components, the heat sink having a cooling plate on each of its two opposing outer surfaces, the electronic components being in thermal contact with the opposing outer surfaces of the cooling plates with their heat-emitting sides facing each other.

[0022] The opposing exterior surfaces of the electronic component and cooling plate may have complementary fastening means, preferably through holes and threaded receptacles.

[0023] The heat sink may be mounted on an opposing cooling plate with an electronic component to form a pre-assembled assembly, for example a pre-assembled assembly of a relatively large IT unit, for example a pre-assembled assembly of a server housing, into which, for example, two electronic components are inserted via plug connectors into slots in the main circuit board. In this case, the heat sink forms the load-bearing structure of the electronic components. The heat sink is therefore particularly suitable for retrofitting existing IT infrastructure, since by inserting an already pre-assembled electronic component into the heat sink, the electronic component is retrofitted and liquid cooling is provided in a single assembly step.

[0024] The electronic components can be designed as plug-in cards having plug connectors along their outer edges for vertically mounting and electrically connecting the electronic components to respective ones of a number of slots on the main circuit board, and the distance between the outer surfaces of the heat sinks can be precisely dimensioned so that two electronic components have a distance from each other between their plug connectors that corresponds to the grid spacing of the number of slots. [Brief description of the drawings]

[0025] Further details of the invention are explained with reference to the accompanying drawings. [Figure 1] 1 illustrates an exemplary embodiment of a heat sink according to the present invention in a perspective view; [Diagram 2] 2 shows a cross-sectional view of the heat sink according to FIG. [Diagram 3] FIG. 3 is a detailed view of the heat sink according to FIG. 2. [Figure 4] 3 shows the heat sink according to FIG. 2 in a perspective view. [Diagram 5] FIG. 5 is a detailed view of the heat sink according to FIG. [Figure 6] 1 shows a further exemplary embodiment of a heat sink according to the invention in a perspective view; [Figure 7]FIG. 7 is a cross-sectional view of the heat sink according to FIG. [Figure 8] 1 shows a schematic diagram of a cooling device according to the invention; [Figure 9] FIG. 9 is a detailed view of the cooling device according to FIG. 8. [Figure 10] FIG. 9 is a side view of the cooling device according to FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] 1 shows an exemplary embodiment of a heat sink 1 according to the invention. The heat sink 1 essentially consists of a thermally conductive heat sink 2 with a channel structure for a cooling fluid inside, which channel structure is fluidly accessible via a forward flow 4 and a return flow 5 at the end side of the heat sink 2. In contrast to heat sinks known from the prior art, the heat sink 2 has on both of its opposite outer faces a respective cooling plate 6 which is thermally coupled via the channel structure inside the heat sink 2 and thus respectively supplied with cooling power. Thus, both cooling plates 6 can be brought into thermal contact for mounting IT components requiring cooling, for example with a CPU or GPU, by mounting, for example, the heat-emitting side of said electronic components directly on the cooling plates 6.

[0027] 2 to 5 in particular show a channel structure 3 formed inside the heat sink 2 and thermally and mechanically coupled to two opposing cooling plates 6 of the heat sink 2. As shown in FIG.

[0028] The channel structure 3 is composed of channel sections 7 running parallel to each other, meandering through the heat sink 2 and parallel to the cooling plate 6. The channel sections 7 are each divided into a number of subchannels 8. The subchannels 8 of the same channel section 7 are fluidically separated from each other by partition walls 9 separating the subchannels, so that no exchange of liquid occurs between the subchannels along the contour of the subchannel 8. All subchannels 8 of the same channel section 7 open at the end side of the heat sink 2 into a fluid transition 10, where the flows of the subvolumes of the subchannels 8 are then combined. Furthermore, the flows of the combined subvolumes are deflected by 180° in the fluid transition 10 in the direction of the fluid flow and transferred to the next channel section 7, where the flows of the volumes are then divided into several subchannels 8.

[0029] As can be seen, the channel structure 3 has four channel sections 7, each divided into a different number of subchannels 8. In the direction of fluid flow from the supply inlet 4 to the return inlet 5, each subsequent channel section 7 has more subchannels 8 than the preceding channel section 7 in the direction of flow, and all subchannels 8 of the heat sink 2 have the same opening cross-sectional area. Thus, an increase in the number of subchannels results in a decrease in the flow velocity at the transition to each subsequent channel section 7 in the direction of flow. Furthermore, the number of partition walls 9 and the area of ​​the cooling plate 6 with which the channel section or the fluid passing through the channel section is in thermal contact are increased, as a result of which an almost constant cooling power can be provided to the cooling plate 6, even when the temperature of the cooling fluid increases.

[0030] Furthermore, FIG. 3 shows that the partition walls 9 are constructed integrally with the cooling plate 6, for example by means of additive manufacturing methods. Furthermore, the partition walls 9 have a surface structure 12 on their inside facing the subchannels 8, as a result of which the effective cross-sectional area between the cooling fluid and the partition walls is increased and, if appropriate, turbulence can be generated. To improve the heat exchange between the cooling fluid and the partition walls 9, turbulence can be generated. The partition walls 9 can also be directly transferred to the cooling plate 6 or constructed integrally with the cooling plate 6, so that optimal heat transfer from the cooling plate 6 to the cooling fluid flowing in the subchannels 8 via the partition walls 9 and the surface structure 12 is achieved.

[0031] Figures 4 and 5 show that the fluid transition portion 10 can be configured as a recess designed to be particularly advantageous for construction using additive manufacturing methods, with all sub-channels 8 of two channel sections 7 fluidly connected to each other via the fluid transition portion 10 opening into the fluid transition portion 10.

[0032] 6 and 7 show a further embodiment of a heat sink 1 according to the invention, which, in contrast to the above-mentioned embodiment, has a cooling plate 6 only on one of its two opposite sides and has a supply inlet 4 and a return inlet 5 on the side opposite the cooling plate 6. The cross section according to FIG. 7 further shows a preferred one-piece embodiment of the heat sink 1, so that, on the one hand, an optimal heat transfer between the heat sink 1 and the cooling fluid flowing through it is achieved, and, on the other hand, an optimal heat distribution within the heat sink 1 is achieved, so that the entire thermal capacity of the heat sink 1 is available for heat transfer from the electrical components requiring cooling to the heat sink 1. The heat sink 1 according to FIGS. 6 and 7 is preferably manufactured by additive manufacturing methods, so that the aforementioned one-piece nature is guaranteed.

[0033] 8 to 10 show an embodiment of the cooling device according to the invention, in which one electronic component 100, here a GPU, is mounted, for example by screwing, on the opposing outer surfaces forming the cooling plate 6 (see FIG. 1), such that the electronic component 100 is in heat-transfer contact with one of the two opposing cooling plates 6, respectively. The IT components 100 can be configured as plug-in cards and mounted in corresponding slots 201 on the main circuit board 200, as known from the prior art, for installation in the server housing 300. In contrast to the prior art, the heat sink 1 according to the invention allows two IT components 100 together with the heat sink 1 arranged between them to form a pre-assembled assembly which can be mounted in a single assembly step, i.e. by inserting the plug-in connectors 102 of the two IT components 100, respectively, into one of the slots 201 in the server housing 300 or on the main circuit board 200, without requiring further assembly steps to provide cooling for the IT components. It is only necessary to connect the supply line 301 and the return line 302 to the supply or return inlet of the heat sink 1, as appropriate.

[0034] Therefore, particularly advantageously, the heat sink 1 has a dimension perpendicular to the two cooling plates 6 that defines a distance for the two plug connectors 102 of the IT component 100 when the IT component 100 is mounted on the cooling plates 6, which corresponds to the distance between two slots 201 or the grid spacing of a number of slots 201.

[0035] The heat sink 1 and the IT component 100 may have complementary fastening means that allow the IT component to be connected in a press-fit manner to the heat sink 1 to form an integral structural unit. For example, the IT component 100 may have a through hole 101 and the heat sink 1 may have a threaded hole 11, by which the IT component 100 may be attached to the heat sink 1 with a screw.

[0036] 10 shows that with the heat sink 1 according to the invention, maximum packing density of IT components 100 in a server housing 300 can be achieved. In particular, the heat sink 1 can have a dimension perpendicular to the cooling plate 6 that is precisely dimensioned such that for a given grid dimension of slots 201 according to industry standards and for IT components 100 mounted in these slots 201 with their heat dissipation surfaces facing each other, the heat sink 1 precisely fills the remaining intermediate space between the heat dissipation surfaces of the IT components 100 facing each other, ensuring optimal heat transfer between the IT components 100 and the heat sink 1 in addition to optimal space utilization. [Explanation of symbols]

[0037] 1 Heatsink 2 Heat sink 3 Channel Structure 4 Supply inlet 5 Return Exit 6 Cooling Plate 7 Channel Section 8 Subchannels 9 Partition Wall 10 Fluid transition section 11 Threaded socket 12 Surface structure 100 Electronic Components 101 Through hole 102 Plug Connector 200 Main circuit board 201 Slots 300 Server Housing 301 Supply Line 302 Return Line

Claims

1. A heat sink (1) for at least one microchip (100), preferably for a GPU or a CPU, comprising a thermally conductive heat sink (2) having a channel structure (3) for a cooling fluid with a supply inlet (4) and a return inlet (5), characterized in that the heat sink (1) has one cooling plate (6) on each of two opposing outer faces of the heat sink (2) thermally and mechanically coupled to the channel structure (3).

2. 2. The heat sink (1) according to claim 1, wherein the channel structure (3) is guided in a serpentine manner through the heat sink (2) parallel to at least one cooling plate (6) or both cooling plates (6).

3. 3. The heat sink (1) according to claim 1 or 2, wherein the channel structure (3) consists of a plurality of channel sections (7) connected to each other via fluid transitions (10), at least one of the channel sections (7) consisting of a plurality of sub-channels (8) that are at least partially fluidically separated from each other along the channel section (7).

4. 4. The heat sink (1) according to claim 3, wherein the mutually separated sub-channels (8) are thermally coupled to the at least one or both cooling plates (6), preferably the sub-channels (8) are fluidically separated from each other via a partition wall (9) which is thermally and mechanically coupled to the at least one or both cooling plates (6) and particularly preferably formed integrally with the at least one or both cooling plates (6).

5. 5. The heat sink (1) according to claim 3 or 4, wherein in the case of the heat sink (2) having one cooling plate (6) on each of its opposing outer faces, the sub-channel (8) extends at least partially, preferably entirely, over the entire distance between the two cooling plates (6).

6. 6. The heat sink (1) according to claim 3, wherein the channel section (7) comprises a plurality of sub-channels (8) fluidically separated from one another along the channel section (7), and the channel section (7) opens directly into the fluid transition portion (10) together with all the sub-channels (8).

7. 7. The heat sink (1) according to any one of claims 3 to 6, wherein the channel structure (3) has a plurality of channel sections (7) consisting of a plurality of sub-channels (8) fluidically separated from one another along respective channel sections (7), the channel sections (7) having a different number of sub-channels (8).

8. 8. The heat sink (1) according to claim 7, wherein a second channel section (7) following a first channel section (7) in a flow direction from the supply (4) to the return (5) has a greater number of sub-channels (8) than the first channel section (7).

9. 9. The heat sink (1) according to claim 7 or 8, wherein the channel section (7) has a number of sub-channels (8) that increases steadily from channel section (7) to channel section (7) in the direction of flow from the supply (4) to the return (5).

10. 9. The heat sink (1) according to any one of claims 2 to 8, wherein the sub-channels (8) of all channel sections (7) run parallel to one another and the sub-channels (8) have a channel cross-section which is preferably constant, particularly preferably substantially identical or identical, for all sub-channels (8).

11. 10. The heat sink according to claim 2, wherein the channel section (7) opening into the return inlet (5) has a channel width which corresponds to at least twice, preferably at least three times, particularly preferably at least four times the width of the channel section (7) opening into the supply inlet (4).

12. 10. The heat sink (1) according to any one of claims 2 to 9, wherein the return inlet (5) has a cross-sectional area that is at least twice, preferably at least three times, particularly preferably at least four times, larger than the supply inlet (4).

13. 13. A cooling device having at least one heat sink (1) according to any one of claims 1 to 12, comprising one cooling plate (6) on each of two opposing outer surfaces of the heat sink (2) and at least two microchips (100) in thermal contact with the opposing outer surfaces of the cooling plates (6) with their heat releasing sides facing each other.

14. 14. The cooling device according to claim 13, wherein the opposing outer surfaces of the electronic component (100) and the cooling plate (6) have complementary fastening means (11, 101), preferably a through hole (101) and a threaded socket (11).

15. the electronic components (100) are designed as plug-in cards and have plug connectors (102) along the outer edge of the plug-in card for vertically mounting and electrically connecting the electronic components (100) to respective individual slots (201) of a multiplicity of slots (201) on a main circuit board (200), the distance between the outer surfaces of the heat sink (2) being dimensioned such that the distance between the plug connectors (102) of the two electronic components (100) corresponds to the grid spacing of the multiplicity of slots (201); 14. A cooling device according to claim 12 or 13.

Images