CN112188792A

CN112188792A - Heat radiator

Info

Publication number: CN112188792A
Application number: CN201910597803.2A
Authority: CN
Inventors: 李江莉; S·萨卢塔其; V·博卡德; 罗成; 徐泽林
Original assignee: Eaton Intelligent Power Ltd
Current assignee: Eaton Intelligent Power Ltd
Priority date: 2019-07-03
Filing date: 2019-07-03
Publication date: 2021-01-05

Abstract

The invention relates to a heat sink, comprising: a base adapted to form thermal contact with the heat generating member; and a plurality of fins arranged on the base at intervals; the base is configured to transfer heat emitted by the heat generating component to each fin, wherein the base comprises a heat conducting shell and an inner cavity defined in the heat conducting shell, and a first phase change cooling medium is filled in the inner cavity; an inner flow passage is formed in at least one of the plurality of fins, and a second phase change cooling medium is filled in the inner flow passage.

Description

Heat radiator

Technical Field

The invention relates to the technical field of heat dissipation of electrical elements, in particular to a heat radiator.

Background

The electrical components generate a large amount of heat during operation, thereby increasing the temperature. If the heat cannot be dissipated in time, the continuous high temperature will damage the electrical components, even make the electrical components unable to work continuously. To solve the problem of heat dissipation of electrical components, fin heat sinks have been developed, which generally include a plurality of fins arranged in a certain pattern. The heat generated by the electric element can be transferred to the fin tip from the fin root, so that the heat around the electric element is taken away, and the purpose of cooling is achieved. However, since a very small volume of the electrical component can generate a very large amount of heat, the arrangement range or fin area of the fins may be far beyond the volume range/cross-sectional range of the electrical component in order to achieve a desired heat dissipation effect. This presents the problem that only the "central" fins next to the electrical component can effectively participate in heat dissipation, whereas the "peripheral" fins, which are remote from the electrical component, cannot.

For this reason, various improved structures have been developed. For example, chinese patent No. CN207969240U, published at 12.10.2018, describes a heat sink in which the thickness of a plurality of fins is gradually reduced in a direction away from a central electrical component, and the gaps between the fins are gradually increased in a direction away from the central electrical component. This solution does not actually solve the problem of the uneven transfer of the heat dissipated by the electrical component to each fin, and it causes further problems, since fins of different specifications are designed and machined for the same heat sink, and the mounting positions of these fins of different specifications have corresponding requirements, which limits the applicability of the fins and complicates the structure and assembly of the heat sink.

Disclosure of Invention

The present invention is directed to a heat sink that solves at least some of the above problems.

According to an aspect of the present invention, there is provided a heat sink including: a base adapted to be in thermal contact with the heat generating member; and a plurality of hollow fins arranged at intervals on the base; wherein the base is configured to transfer heat dissipated by the heat generating member to each fin, wherein the base comprises a heat conductive housing and an inner chamber defined within the heat conductive housing, the inner chamber being at least partially filled with a first phase change cooling medium; at least one of the plurality of hollow fins has an inner flow passage formed therein, the inner flow passage being at least partially filled with a second phase change cooling medium.

The heat dissipated by the heating element enables the first phase change cooling medium to form vapor-liquid two-phase circulation in the inner chamber of the base. That is, by virtue of such a two-phase cycle and the heat conductive property of the heat conductive casing, it is possible to uniformly diffuse and transfer the heat emitted from the heat generating member to each fin even if the fin is located at the periphery of the fin region, for example, the fin closest to the outside. Thus all fins can effectively participate in heat dissipation. The heat radiator only needs to form an inner chamber in the heat conducting shell of the base to prevent the first phase change cooling medium from overflowing, and all the fins can be of uniform specification and have no sequence requirement on installation. The second phase change cooling medium in the inner flow channels of the fins also begins a vapor-liquid two-phase cycle upon receiving the transferred heat, transferring the heat from the roots of the fins near the base to the tips of the fins far from the base. The radiator is simple in structure and easy to realize, and the radiating efficiency can be greatly improved.

Meanwhile, different from the prior art that cooling is carried out only by means of sensible heat exchange, in the invention, heat exchange in the base and the fins comprises temperature reduction (sensible heat exchange) and condensation (latent heat exchange), and the thermosiphon effect accompanied with the phase change phenomenon can realize very high heat conduction efficiency (compared with the prior art that heat is transferred only by sensible heat, the heat efficiency is improved by multiple orders of magnitude).

Preferably, a plurality of slots are formed on the heat-conducting casing at intervals, and the plurality of fins are inserted into the plurality of slots. This provides a fin mounting structure of a simple structure.

Preferably, the at least one fin includes: a plate portion having two opposed planes; and a convex portion protruding from at least one of the two planes of the plate portion, the convex portion defining the inner flow passage. Thus, the plate portion forms a "concave portion" with respect to the convex portion. The concave-convex structure enlarges the heat exchange area of the fin, and the concave-convex structure increases the turbulent flow between the fin and the surrounding atmosphere, so that the heat exchange efficiency is greatly improved.

Preferably, the convex portion includes: a plurality of first raised sections arranged at intervals, wherein each first raised section extends in a first direction away from the base; and a second convex section extending in a second direction at an angle to the first direction to connect the plurality of first convex sections, the plurality of first convex sections communicating with each other via the second convex section. Thus, a structure of the convex portion is provided which is simple in structure and easy to implement.

Preferably, the internal chamber in the base and the internal flow passage in the at least one fin are in communication with each other. Therefore, the first phase change cooling medium and the second phase change cooling medium are allowed to circularly exchange heat in a larger range, so that the heat radiator can dissipate heat generated by the heat generating component uniformly, uniformly and quickly.

Preferably, the inner flow channel in at least one fin of the plurality of hollow fins far away from the heat generating member and the inner cavity in the base are not communicated with each other. This allows the heat sink to be manufactured in large numbers in a simpler, cost-effective manner without significantly affecting the overall performance of the heat sink.

Preferably, at least one of the plurality of hollow fins is formed by two plates extending generally parallel to each other, wherein the two plates have a first end connected to the base and a second end extending away from the base, wherein the two plates are joined to each other at the second end to form an inner flow passage within the fin, wherein the inner flow passage communicates with the inner chamber at the first ends of the two plates. Thereby, it is allowed to realize high-efficiency heat exchange with a simple process.

Preferably, each two adjacent fins of said plurality of hollow fins are in communication with each other at the second end of the plate. Thus, the hollow fins may be looped, which may provide more cooling area so that better cooling is possible. This helps to circulate the steam between the various fins to enhance heat exchange through greater mixing and diffusion.

Preferably, at least one of the plurality of hollow fins is formed by two plates inclined relative to each other, wherein the two plates have a first end connected to the base and a second end extending away from the base, wherein the two plates are joined to each other at the second end to form an inner flow passage in the shape of a triangle within the fin, wherein the inner flow passage communicates with the inner chamber at the first end of the plate. This allows the overall height of the fin to be reduced without changing the cross-sectional area of the inner flow path, thereby contributing to the miniaturization of the heat sink.

Preferably, adjacent plates of each two adjacent fins of the plurality of hollow fins enclose an angle, wherein the angle is in the range of 45 degrees to 135 degrees. Thereby, it is possible to make each fin have a larger heat exchange area available for condensing the phase change cooling medium and a better air flow across the entirety of the fins, while keeping the height of the fins constant.

Preferably, an angle θ enclosed by each two adjacent fins near the heat generating member is larger than an angle enclosed by each two adjacent fins away from the heat generating member to both sides. This may thereby reduce the total number of fins required in the heat sink, thereby reducing the manufacturing cost of the heat sink.

Preferably, a partition is provided in the base, wherein the partition is used to divide the inner chamber within the base into a plurality of subchambers, wherein each subchamber is assigned to one of the plurality of hollow fins. Thereby, it is allowed to increase the turbulence and diffusion of the phase change cooling medium in the limited space, which also helps to quickly diffuse heat, dissipate more heat and significantly reduce hot spots.

Additional features and advantages of the invention will be set forth in part in the description which follows, and in part will be apparent to those having ordinary skill in the art upon examination of the following, or may be learned from the practice of the invention.

Drawings

Embodiments of the invention are described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 is a schematic view of a heat sink assembled with a heat generating member according to an embodiment of the present invention;

FIG. 2 is a schematic view of the heat sink of FIG. 1 from a different perspective;

FIG. 3 is an exploded schematic view of a heat sink according to a first embodiment of the present invention;

FIG. 4 is an enlarged view at A of FIG. 3;

fig. 5 is a plan view of a heat sink assembled with a heat generating member according to a first embodiment of the present invention;

fig. 6 is a schematic perspective view of a heat sink according to a second embodiment of the present invention;

FIG. 7 is a cross-sectional view of a heat sink according to a second embodiment of the present invention;

fig. 8 is a schematic perspective view of a heat sink according to a third embodiment of the present invention;

FIG. 9 is a cross-sectional view of a heat sink according to a third embodiment of the present invention;

fig. 10 is a schematic perspective view of a heat sink according to a fourth embodiment of the present invention;

fig. 11 is a cross-sectional view of a heat sink according to a fourth embodiment of the present invention.

In the present invention, the same or similar reference numerals denote the same or similar features.

List of reference numerals:

1. 1A, 1B, 1c. a heat generating member; a heat sink; 3. 3A, 3B, 3c. a base;

4. 4A, 4B, 4c fins; 5. a housing; 51. a first bonding surface;

52. a second bonding surface; 53. a groove; 41. a plate portion; 42. a convex portion;

421. a first raised section; 422. a second raised section; 43A, 43B, 43C. first end

44A, 44B, 44c. a second end; 45A, 45B, 45c. first plate;

46A, 46B, 46c. a second plate; 61. a first phase change cooling medium;

62. a second phase change cooling medium; 7. a separator; 71. sub-chamber

Detailed Description

Referring now to the drawings, illustrative versions of the disclosed apparatus will be described in detail. Although the drawings are provided to present some embodiments of the invention, the drawings are not necessarily to scale of particular embodiments, and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present disclosure. The position of some components in the drawings can be adjusted according to actual requirements on the premise of not influencing the technical effect. The appearances of the phrase "in the drawings" or similar language in the specification are not necessarily referring to all drawings or examples.

Certain directional terms used hereinafter to describe the drawings, such as "inner", "outer", "above", "below", and other directional terms, will be understood to have their normal meaning and refer to those directions as they normally relate to when viewing the drawings. Unless otherwise indicated, the directional terms described herein are generally in accordance with conventional directions as understood by those skilled in the art.

The terms "first," "second," and the like, as used herein, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another.

A first exemplary embodiment of a heat sink according to the present invention is shown in its entirety in fig. 1 and 2, wherein the heat sink is indicated with reference numeral 2. As shown, the heat sink 2 is mounted with the heat generating member 1 to form a thermal contact therebetween, and the heat generating member 1 may be an electric component, for example. The electrical component may be, for example, an inverter, a power electronics device (e.g., a power transistor), a contactor, a circuit interrupter, an Uninterruptible Power Supply (UPS), a medium-high voltage inverter (MVD), or a computer data center, among others. As an example, the electrical component herein may be, for example, a power electronic device.

The heat sink 2 includes a base 3 and a plurality of fins 4 mounted on the base 3. Referring to fig. 3, the heat conductive casing 5 of the base 3 is preferably substantially flat and includes two flat surfaces opposite to each other up and down, i.e., a first engaging surface 51 for engaging with the heat generating member 1 and a second engaging surface 52 for attaching the fins 4. The heat generating member 1 is preferably attached to the first bonding surface 51 at a central position of the first bonding surface 51, which facilitates uniform diffusion and transfer of heat emitted from the heat generating member 1 by the heat conductive housing 5. Formed within the heat conductive housing 5 is an inner chamber (not shown) which extends continuously and preferably covers the fin area formed by substantially all of the fins 4. The inner chamber may be vacuum. The interior chamber is preferably partially filled with a first phase change cooling medium, such as pure water. The inner chamber may prevent the first phase change cooling medium from overflowing. When heat enters the heat-conducting shell 5 through heat conduction from the heating element 1, the first phase-change cooling medium close to the periphery of the heating element 1 can rapidly receive the heat generated by the heating power electronic device and absorb the phase-change latent heat to be gasified into steam, and a large amount of heat energy is taken away. Since the density of the steam is lower than that of the liquid medium, the steam generated near the first joint surface 51 will rise and spread to the second joint surface 52 for mounting the fins 4 under the action of the thermo-siphon effect, i.e. when the steam in the inner chamber will spread from the central high-temperature region (or high-pressure region) to the peripheral low-temperature region (or low-pressure region), the steam will quickly condense into liquid and release heat energy when contacting the lower-temperature inner wall of the heat-conducting shell 5. The condensed liquid flows back to the position of the heat generating member 1 or a position near the heat generating member 1, thereby completing one cycle. The heat released by the condensation of the first phase change coolant medium is received by the fins 4. Thus, the first phase change cooling medium forms a two-phase circulation system of liquid and vapor together within the inner chamber of the heat conductive housing 5. By virtue of this circulation of the first phase-change cooling medium within the heat-conducting enclosure 5, and by virtue of the heat-conducting properties of the heat-conducting enclosure 5, the heat emitted by the heat-generating member 1 can be uniformly transferred to each of the fins 4 in the fin region, enabling them to effectively participate in heat dissipation. It is preferable that a micro structure capable of guiding the condensed liquid back to the position of the heat generating member 1 or a position close to the heat generating member 1 is formed on the inner wall surface of the heat conductive housing 5, and the condensate is refluxed by the capillary action of the micro structure.

A plurality of fins 4 are mounted on the second engagement surface 52 of the thermally conductive outer shell 5. The installation means comprises welding, bonding, tight fit, clamping and the like. As shown in fig. 3 and 4, in the illustrated embodiment, the second engagement surface 52 is substantially parallel to the first engagement surface 51, and the groove 53 extends from the second engagement surface 52 in a direction closer to the first engagement surface 51. A plurality of such grooves 53 are preferably arranged at even intervals on the second engagement surface 52. One fin 4 is inserted into each slot 53 such that all fins 4 are arranged at substantially uniform intervals on the base 3. An adhesive may be applied to one or both of the fins 4 and the slots 53 or other locating structure may be provided to ensure that the fins 4 do not move easily within the slots 53.

Referring to fig. 1-5, the fins 4 define internal flow channels (not shown) therein. In the illustrated embodiment, the plate portion 41 of the fin 4 has two opposed flat surfaces from which the convex portions 42 each project, and the two flat convex portions 42 correspond to define the inner flow passage therebetween. The inner flow passage may be partially filled with a second phase change cooling medium. The inner flow passage can prevent the second phase change cooling medium from overflowing. It will be appreciated that it is also possible that only one plane of the plate portion 41 forms the raised portion 42, and that an internal flow passage may also be defined between the raised portion 42 and the opposite plane.

The first phase change cooling medium and the second phase change cooling medium may be made of the same material or different materials.

According to the illustrated embodiment, the raised portion 42 includes a plurality of first raised sections 421 arranged at intervals, each first raised section 421 extending from a root of the fin 4 near the base 3 to a tip of the fin 4 away from the base 3. The extending direction of the first convex section 421 is herein set as the first direction. The first direction is preferably perpendicular to the first engagement surface 51 and/or the second engagement surface 52 of the thermally conductive housing 5. The second convex sections 422 extend in a second direction at an angle to the first direction and are connected to all the first convex sections 421 on the same side (above or below the first convex sections 421 in the drawing) of these first convex sections 421, while on the opposite side, these first convex sections 421 are connected to another second convex section 422.

These first and second

convex sections

421 and 422 are not only connected to each other, but also communicate with each other. Thus, the first and second raised

sections

421 and 422 together define the inner flow channels of the fin 4. The first and second raised

sections

421 and 422 may be only a few millimeters wide. The second phase change cooling medium completes vapor-liquid circulation in the inner flow passage.

In the inner flow passage, the second phase change cooling medium is initially in a liquid state at a position near the root (i.e., the second joint surface 52) of the fin 4. After the heat generated from the heat generating member 1 is uniformly transferred to each fin 4 through the base 3 in the above manner, the liquid second-phase cooling medium near the root of the fin 4 rapidly receives heat from the outside and absorbs latent heat of phase change and is vaporized into steam. Since the steam is light, it spreads upward along the first convex section 421 by the thermosiphon effect, and after contacting the lower temperature inner wall of the tip of the fin 4, the steam condenses to release heat. The liquid condensed at the tips of the fins 4 flows back to the roots of the fins 4 under the action of gravity, completing one cycle. By this vapor-liquid circulation of the second phase change cooling medium in the inner flow channels of the fins 4, heat is transferred from the roots to the tips of the fins 4.

As is apparent from the above, according to the first embodiment of the present invention, by providing cavities partially filled with phase-change cooling media in the base 3 and the fins 4 of the heat sink 2, these phase-change cooling media are first heated by sensible heat exchange (heat conduction) and then vaporized by latent heat exchange. The vapour from the evaporation of the liquid rises to contact the upper side of the base 3 of the radiator and thus the inner surface of the hollow fins 4. Where it is cooled down (sensible heat exchange) and subsequently condensed (latent heat exchange) by the cooling effect of the external forced cooling air. The liquid condensed at the inner surfaces of the hollow fins then flows back to the base of the heat sink under the influence of gravity and is circulated back and forth. The thermosiphon effect, which is accompanied by the phase change phenomenon, will achieve very high heat transfer efficiency (thermal efficiency is improved by several orders of magnitude compared to the conventional method of transferring heat only by sensible heat).

When comparing the power electronic device provided with the heat sink 2 according to the first embodiment of the invention with a power electronic device with a conventional forced air cooled heat sink, it can be observed that the hot spot temperature is significantly reduced, for example by 50%. This is due at least to the fact that heat sink designs with thermosiphons with phase change cooling can provide much higher thermal conductivity, which in turn enables much higher thermal conductivity flux compared to conventional fin systems. Thus, a wide range of energy density enhancement can be achieved while maintaining the same temperature differential between the power electronics and the heat sink as with prior fin systems. This will ensure that a significantly increased energy density is achieved at the same hot spot temperature, which is clearly very advantageous for improving the performance or functionality of the electrical device.

Further, a second exemplary embodiment of a heat sink according to the present invention is shown in its entirety in fig. 6 and 7. As shown in the figure, a plurality of heat generating members 1A can also be attached to the base 3A, which facilitates the heat emitted from the heat generating members 1 to be uniformly diffused and transferred. Unlike the first embodiment, in the second embodiment, the inner chamber in the base 3A and the inner flow passage in at least one of the plurality of fins 4A are communicated with each other. Preferably, as shown in fig. 7, the inner chamber in the base 3A and the inner flow passages in all of the plurality of fins 4A are communicated with each other.

As shown in fig. 7, in which each of the plurality of hollow fins 4A is formed by a first plate 45A and a second plate 46A extending substantially parallel to each other, the two

plates

45A and 46A may be made of a material having a good heat conductivity, such as copper, a copper alloy, aluminum, or an aluminum alloy. Wherein the pair of

plates

45A and 46A can be fixedly connected at their first ends 43A (below as shown in fig. 7) to the base 3A, for example via a glue-bonding process or a brazing welding process, respectively, while at their second ends 44A extending away from the base 3A, the pair of

plates

45A and 46A can here be joined together, for example, in a slightly bent manner with respect to each other, so as to join each other to form an inner flow channel within the fin 4A, in which the second phase-change cooling medium 62 is preferably partially filled. Since the pair of

plates

45A and 46A are communicated with the inner chamber of the base 3A at the first end 43A, the first phase-change cooling medium 61 in the inner chamber of the base 3A can rise and extend into the inner flow channel of the fin 4A when being heated and vaporized, and the condensed fluid of the second phase-change cooling medium 62 in the fin 4A can also flow into the inner chamber of the base 3A, so that the first phase-change cooling medium 61 and the second phase-change cooling medium 62 can perform circulating heat exchange in a larger range, and the heat generated by the heat generating component 1A can be dissipated uniformly and quickly by the heat sink 2.

It is to be noted that although the inner chamber of the base 3A is shown in fig. 7 as being in communication with the inner flow channels in each of the fins 4A, it is also permissible for those skilled in the art to have the inner chamber of the base 3A be in communication with the inner flow channels in one or a part of the plurality of fins 4A as needed, which may be achieved, for example, by forming the fins 4A as closed sides on the first side 43A through which fluid cannot flow. Specifically, it is preferable that the fins 4A near the heat generating member 1A are kept in fluid communication with the inner chamber of the base 3A, and the joining of the first and second phase-change cooling media is prevented by making the first side 43A closed at the fins 4A far from the heat generating member 1A. The number of fins 4A that need to be in fluid communication depends primarily on the power of the heat generating member 1A and the operating environment of the heat sink, among other factors. Experiments show that the overall performance of the radiator is not obviously affected by adopting the design. This is beneficial to reduce the production cost and the processing difficulty of the heat sink, for example, in the area far away from the heat generating component 1A, the closed fin 4A may be directly mounted to the base 3A by using a simpler bonding or welding method.

Further, a third exemplary embodiment of a heat sink according to the present invention is shown in its entirety in fig. 8 and 9. As shown in the figure, a plurality of heat generating members 1B may also be attached to the base 3B, which facilitates uniform diffusion and transfer of heat emitted from the heat generating members 1B. As shown in fig. 9, in the third embodiment, too, the plurality of hollow fins 4B are formed by a first plate 45B and a second plate 46B extending substantially in parallel with each other. Further, wherein the pair of

plates

45B and 46B are also fixedly connected at the first ends 43B thereof (downward in fig. 9) to the base 3B, unlike fig. 7, each two adjacent fins 4B of the plurality of hollow fins 4B are in communication with each other at the second ends 44B of the plates. For example, such communication may be achieved by joining two by two the first plates 45B and two by two the second plates 46B in each two adjacent fins 4B. More preferably, as shown in fig. 7, the inner chamber in the base 3B and the inner flow passages in all of the plurality of fins 4B are communicated with each other.

Although the inner chamber of the base 3B is shown in fig. 9 as communicating with the inner flow channels in each of the fins 4B, it is also permissible for one skilled in the art to communicate the inner chamber of the base 3B with the inner flow channels in one of the plurality of fins 4B or a part of the fins 4B as needed, which can be achieved, for example, by forming the fins 4B on the first side 43B as closed sides through which fluid cannot flow. Specifically, it is preferable that the fins 4B near the heat generating member 1B are in fluid communication with the inner chamber of the base 3B, and that the first side 43B is closed at the fins 4B far from the heat generating member 1B to prevent the first and second phase-change cooling media from merging. The number of fins 4B that need to be in fluid communication depends mainly on the power of the heat generating member 1B and the operating environment of the heat sink, among other factors. Experiments show that the overall performance of the radiator is not obviously affected by adopting the design. This is beneficial to reduce the production cost and the processing difficulty of the heat sink, for example, in the area far away from the heat generating component 1B, the closed fins 4B may be directly mounted to the base 3B by using a simpler bonding or welding method.

Likewise, a second phase change cooling medium 62 is preferably partially filled within the inner flow passage. Since the pair of

plates

45B and 46B are communicated with the inner chamber of the base 3B at the first end 43B, the first phase-change cooling medium 61 in the inner chamber of the base 3B can be lifted and extended into the inner flow channel of the fin 4B when being heated and vaporized, and the condensed fluid of the second phase-change cooling medium 62 in the fin 4B can also flow into the inner chamber of the base 3B, so that the first phase-change cooling medium 61 and the second phase-change cooling medium 62 can perform circulating heat exchange in a larger range, and the heat sink 2 can dissipate the heat generated by the heat generating component 1B uniformly and quickly.

Thereby, in this embodiment it is possible to allow the phase change cooling medium to be looped flowing within the plurality of fins 4B, which facilitates circulation of steam between the plurality of different fins 4B to enhance heat exchange by stronger mixing and diffusion. Also, this configuration in the third embodiment may provide more cooling area, thereby allowing better heat spreading across multiple different areas of the heat sink to avoid hot spots.

Further, a fourth exemplary embodiment of a heat sink according to the present invention is shown in its entirety in fig. 10 and 11. As shown in the figure, a plurality of heat generating members 1C may also be attached to the base 3C, which facilitates the heat generated by the heat generating members 1C to be uniformly diffused and transferred. As shown in fig. 11, in the third embodiment, a plurality of hollow fins 4C are formed by

first plates

45C and 46C inclined relative to each other, wherein the pair of

plates

45C and 46C are also fixedly connected at first ends 43C thereof (downward in fig. 11) to the base 3C so as to allow the internal flow passages within the fins and the chambers within the base 3C to communicate with each other. And, the pair of

plates

45C and 46C are joined to each other at the second end 44C to form an inner flow passage in the shape of a triangle inside the fin 4C. This allows the overall height of the fin 4C to be reduced without changing the cross-sectional area of the inner flow path, thereby contributing to downsizing of the heat sink.

plates

45C and 46C are communicated with the inner chamber of the base 3C at the first end 43C, the first phase-change cooling medium 61 in the inner chamber of the base 3C can be lifted and extended into the inner flow channel of the fin 4C when being heated and vaporized, and the condensed fluid of the second phase-change cooling medium 62 in the fin 4C can also flow into the inner chamber of the base 3C, so that the first phase-change cooling medium 61 and the second phase-change cooling medium 62 can perform circulating heat exchange in a larger range, and the heat sink 2 can dissipate the heat generated by the heat generating component 1C uniformly and quickly.

Preferably, a partition 7 is provided in the base 3C, which partition can be, for example, a part embedded in the base 3C and having the same height as the base 3C and having a plurality of parallel flaps. The inner chamber in the base 3C can thus be divided by the partition 7 into a plurality of subchambers 71, which, as shown in fig. 11, are each assigned to one of the plurality of hollow fins 4C in such a way that they are located directly below the hollow fins 4C and communicate with one another. In this way, increased turbulence and diffusion of the phase change cooling medium in the confined space is allowed, which also helps to quickly diffuse heat, dissipate more heat and significantly reduce hot spots.

Although each of the inner chambers of the base 3C is shown in fig. 11 as being in communication with the inner flow passages in each of the fins 4C, it is understood by those skilled in the art that it is also permissible to have a part of the inner chambers of the base 3C be in communication with one of the plurality of fins 4C or a part of the inner flow passages in the fins 4C, as necessary. Specifically, it is preferable that the fins 4C near the heat generating member 1C are kept in fluid communication with the inner chamber of the base 3C, and the joining of the first and second phase-change cooling media is prevented by making the first side 43C closed at the fins 4C far from the heat generating member 1B. The number of fins 4C that need to be in fluid communication depends mainly on the power of the heat generating member 1C and the operating environment of the heat sink, among other factors. Experiments show that the overall performance of the radiator is not obviously affected by adopting the design. This is beneficial to reduce the production cost and the processing difficulty of the heat sink, for example, in the area far away from the heat generating component 1C, the closed fins 4C may be directly mounted to the base 3C by using a simpler bonding or welding method.

Preferably, as shown in fig. 11, an angle θ is enclosed between the adjacent first and

second plates

45C and 46C of each two adjacent fins 4C of the plurality of hollow fins 4C, which is particularly advantageous. In particular, if the angle "θ" is increased while keeping the height of the fins 4C constant, this will result in a larger heat exchange area per fin 4C available for condensing the phase change cooling medium and a better air flow across the entirety of the fins. In the present embodiment, the angle θ is in the range of 45 degrees to 135 degrees.

In order to more quickly conduct away the heat generated by the heat generating member 1C, it is preferable that the angle θ enclosed between the adjacent first plate 45C and second plate 46C in the vicinity of the heat generating member 1C is the largest, and may be 135 degrees, for example, so that sufficient heat conduction at the position of the heat generating member 1C can be achieved. As the distance from the heat generating member 1C gradually increases to reduce the amount of heat to be dissipated per unit time, it is possible to allow the angle θ enclosed between the adjacent first and

second plates

45C and 46C to be reduced without affecting the overall heat dissipation performance of the heat sink, while keeping the height of the fin 4C constant, i.e., to make the angle θ enclosed by every two adjacent fins near the heat generating member 1C larger than the angle enclosed by every two adjacent fins away to both sides from the heat generating member 1C.

Specifically, when the heat sink having such a design is viewed from a plan view, a pattern is formed in which the inclination angle of the fins 4C gradually changes toward both sides with the heat generating material 1C as a center. Specifically, the pattern may be such that the closer to the heat generating member 1C, the larger the angle θ enclosed between the first plate 45C and the second plate 46C adjacent to each other, and conversely, the farther from the heat generating member 1C to both sides with the heat generating member 1C as the center, the smaller the angle θ enclosed between the first plate 45C and the second plate 46C adjacent to each other, so that the pattern becomes dense from near to far with the heat generating member 1C as the center. In a top view, it exhibits the visual effect of flowers blooming from the central portion to both sides. By this design, it is allowed to arrange a plurality of fins 4C more optimally without affecting the overall heat radiation performance of the heat sink, so that the total number of fins 4C required in the heat sink can be reduced, which is certainly very advantageous for the manufacturer of the heat sink.

It should be understood that although the description is in terms of various embodiments, not every embodiment includes only a single embodiment, and such description is for clarity purposes only, and those skilled in the art will recognize that the embodiments described herein may be combined as suitable to form other embodiments, as will be appreciated by those skilled in the art.

The above description is only an exemplary embodiment of the present invention, and is not intended to limit the scope of the present invention. Any equivalent alterations, modifications and combinations can be made by those skilled in the art without departing from the spirit and principles of the invention.

Claims

1. A heat sink, comprising:

a base adapted to form thermal contact with the heat generating member; and

a plurality of hollow fins arranged at intervals on the base;

the base is configured to transfer heat emitted by the heat generating component to each fin, wherein the base comprises a heat-conducting shell and an inner chamber defined in the heat-conducting shell, and the inner chamber is at least partially filled with a first phase-change cooling medium;

an inner flow passage is formed in at least one of the plurality of hollow fins, and a second phase change cooling medium is at least partially filled in the inner flow passage.

2. The heat sink of claim 1, wherein the heat conductive housing has a plurality of slots formed therein in a spaced arrangement, the plurality of hollow fins being inserted into the plurality of slots.

3. The heat sink of claim 1, wherein the at least one fin comprises:

a plate portion having two opposed planes; and

a convex portion protruding from at least one of the two planes of the plate portion, the convex portion defining the inner flow passage.

4. The heat sink of claim 3, wherein the raised portion comprises:

a plurality of first raised sections arranged at intervals, wherein each first raised section extends in a first direction away from the base; and

a second raised section extending in a second direction at an angle to the first direction to connect the plurality of first raised sections, the plurality of first raised sections communicating with each other via the second raised section.

5. The heat sink as recited in claim 1 wherein the internal chamber in the base and the internal flow passage in the at least one fin are in communication with each other.

6. The heat sink as claimed in claim 5, wherein the inner flow channel of at least one of the plurality of hollow fins remote from the heat generating member and the inner chamber of the base are not in communication with each other.

7. The heat sink of claim 5, wherein at least one of the plurality of hollow fins is formed from two plates extending generally parallel to each other, wherein two plates have first ends connected to the base and second ends extending away from the base, wherein the two plates are joined to each other at the second ends to form internal flow channels within the fins, wherein the internal flow channels communicate with the internal chamber at the first ends of the two plates.

8. The heat sink as recited in claim 7 wherein each two adjacent fins of the plurality of hollow fins are in communication with each other at the second end of the plate.

9. The heat sink as recited in claim 5 wherein at least one of the plurality of hollow fins is formed by two plates inclined relative to each other, wherein the two plates have a first end connected to the base and a second end extending away from the base, wherein the two plates are joined to each other at the second end to form an inner flow passage in the shape of a triangle within the fin, wherein the inner flow passage communicates with the inner chamber at the first end of the plate.

10. The heat sink of claim 9, wherein adjacent plates of each two adjacent fins of the plurality of hollow fins enclose an angle θ, wherein the angle θ is in a range of 45 degrees to 135 degrees.

11. The heat sink according to claim 10, wherein an angle θ enclosed by each two adjacent fins near the heat generating member is larger than an angle enclosed by each two adjacent fins away from the heat generating member to both sides.

12. The heat sink as recited in claim 9 wherein a divider is provided in the base, wherein the divider is configured to divide the internal chamber within the base into a plurality of subchambers, wherein each subchamber is assigned to one of the plurality of hollow fins.