VAPOR CHAMBER

Abstract

The application relates to a vapor chamber for cooling a heat source, the vapor chamber includes an evaporator proceeding in a first plane and the vapor chamber includes at least a first condenser and a second condenser, wherein the first and second condenser are internally coupled to the evaporator, wherein the first condenser proceeds in a second plane, and the second condenser proceeds in a third plane, wherein the second plane and the third plane are arranged in an angle to the first plane, wherein at least one air fin is provided, wherein the at least one air fin proceeds in a fourth plane, and wherein the first condenser and the second condenser are internally coupled to the air fin, and wherein the evaporator, the first condenser, the second condenser and the air fin form a common internal volume.

Claims

1. A vapor chamber for cooling a heat source, wherein the vapor chamber comprises an evaporator proceeding in a first plane and wherein the vapor chamber comprises at least a first condenser and a second condenser, wherein the first and second condenser are internally coupled to the evaporator, wherein the first condenser proceeds in a second plane, and the second condenser proceeds in a third plane, wherein the second plane and the third plane are arranged in an angle to the first plane, wherein at least one air fin is provided, wherein the at least one air fin proceeds in a fourth plane, and wherein the first condenser and the second condenser are internally coupled to the air fin, and wherein the evaporator, the first condenser, the second condenser and the air fin form a common internal volume.

2. The vapor chamber according to claim 1, wherein the at least one air fin at least in part has a cross section of an air foil.

3. The vapor chamber according to claim 1, wherein at least one of the first condenser, the second condenser and the air fin is provided with an internal capillary structure.

4. The vapor chamber according to claim 3, wherein the capillary structure of at least one of the first condenser, the second condenser and the at least one air fin is formed as a three-dimensional mesh.

5. The vapor chamber according to claim 4, wherein a plurality of air fins is provided being arranged in at least two rows, the at least two rows being arranged one behind the other in an air flowing direction of the vapor chamber, and wherein at least two rows are positioned relative to another in a staggered arrangement.

6. The vapor chamber according to claim 5, wherein at least one condenser is formed in a straight arrangement.

7. The vapor chamber according to claim 1, wherein at least one condenser is formed in at least one of a waved or dendritic arrangement.

8. The vapor chamber according to claim 7, wherein the first plane is arranged parallel to the fourth plane and in that the second plane is arranged parallel to the third plane, and in that the first plane proceeds in a right angle to the second plane.

9. (canceled)

10. (canceled)

11. An arrangement, comprising: a power semiconductor module; and a cooler, wherein the cooler comprises a vapour chamber, the vapor chamber comprises an evaporator proceeding in a first plane, at least a first condenser and a second condenser, wherein the first and second condenser are internally coupled to the evaporator, wherein the first condenser proceeds in a second plane, and the second condenser proceeds in a third plane, wherein the second plane and the third plane are arranged in an angle to the first plane, at least one air fin is provided, wherein the at least one air fin proceeds in a fourth plane, and wherein the first condenser and the second condenser are internally coupled to the air fin, and wherein the evaporator, the first condenser, the second condenser and the air fin form a common internal volume.

12. The vapor chamber according to claim 1, wherein at least one of the first condenser, the second condenser and the air fin is provided with an internal capillary structure.

13. The vapor chamber according to claim 12, wherein the capillary structure of at least one of the first condenser, the second condenser and the at least one air fin is formed as a three-dimensional mesh.

14. The vapor chamber according to claim 13, wherein a plurality of air fins is provided being arranged in at least two rows, the at least two rows being arranged one behind the other in an air flowing direction of the vapor chamber, and wherein at least two rows are positioned relative to another in a staggered arrangement.

15. The vapor chamber according to claim 14, wherein at least one condenser is formed in a straight arrangement.

16. The vapor chamber according to claim 1, wherein the first plane is arranged parallel to the fourth plane and in that the second plane is arranged parallel to the third plane, and in that the first plane proceeds in a right angle to the second plane.

17. The vapor chamber according to claim 5, wherein at least one condenser is formed in at least one of a waved or dendritic arrangement.

18. The vapor chamber according to claim 1, wherein a plurality of air fins is provided being arranged in at least two rows, the at least two rows being arranged one behind the other in an air flowing direction of the vapor chamber, and wherein at least two rows are positioned relative to another in a staggered arrangement.

19. The vapor chamber according to claim 1, wherein at least one condenser is formed in a straight arrangement.

20. The vapor chamber according to claim 2, wherein a plurality of air fins is provided being arranged in at least two rows, the at least two rows being arranged one behind the other in an air flowing direction of the vapor chamber, and wherein at least two rows are positioned relative to another in a staggered arrangement.

21. The arrangement of claim 11, wherein the vapor chamber comprises a plurality of air fins arranged in at least two rows, the at least two rows being arranged one behind the other in an air flowing direction of the vapor chamber, and wherein at least two rows are positioned relative to another in a staggered arrangement.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0058] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. Individual features disclosed in the embodiments can constitute alone or in combination an aspect of the present invention. Features of the different embodiments can be carried over from one embodiment to another embodiment.

[0059] In the drawings:

[0060] FIG. 1 shows a vapor chamber according to an embodiment of the present invention;

[0061] FIG. 2 shows a corner section cut out of the vapor chamber according to FIG. 1;

[0062] FIG. 3 shows a front section cut of a vapor chamber according to FIG. 1;

[0063] FIG. 4 shows a cross section through air fins looking on a condenser of a vapor chamber according to FIG. 1;

[0064] FIG. 5 shows an embodiment of a condenser;

[0065] FIG. 6 shows a further embodiment of a condenser;

[0066] FIG. 7 shows a further embodiment of a condenser;

[0067] FIG. 8 shows a further embodiment of a condenser; and

[0068] FIG. 9 sows a diagram relating to the thermal resistance at different heat loads.

DESCRIPTION OF EMBODIMENTS

[0069] FIG. 1 shows an embodiment of a vapor chamber 10 for cooling a heat source such as for cooling a power semiconductor module, wherein the heat source is not shown as such. The vapor chamber 10 may thus be arranged in thermal contact with the heat source such as with a part of a power semiconductor module, such as with a baseplate, in order to cool the latter.

[0070] The vapor chamber 10 comprises an evaporator 12 proceeding in a first plane 14. The first plane 14 thus defines the orientation of the evaporator 12 which generally may have a plate-like form. The vapor chamber 10 according to FIG. 1 further comprises three condensers 16, i.e. condensers 16.sub.a, 16.sub.b and 16.sub.c which each are internally coupled to the evaporator 12. The condensers 16.sub.a, 16.sub.b and 16.sub.c proceed in respective planes 18.sub.a, 18.sub.b and 18.sub.c, wherein the planes 18.sub.a, 18.sub.b and 18.sub.c are arranged perpendicular to the first plane 14 and are thus arranged parallel to each other. The planes 18.sub.a, 18.sub.b and 18.sub.c are identical and comprise the second plane and the third plane. FIG. 1 further sows that a plurality of air fins 20 is provided, wherein the air fins 20 are arranged parallel to each other and in particular in a fourth plane 22.

[0071] With regard to the evaporator 12, the condensers 16.sub.a, 1 6.sub.b and 16.sub.c and the air fins 20, it is provided that these parts form a common internal volume. In other words, these parts are internally coupled to each other.

[0072] FIG. 1 thus shows an external view of a 3-dimensional vapor chamber 10 in which the evaporator 12 with its baseplate is shown at the bottom, three condensers 16.sub.a, 16.sub.b and 16.sub.c are shown vertically and the numerous condenser-airfoils as air fins 20 are shown horizontally in between. The number of airfoils, or air fins 20, respectively, is determined to achieve the prescribed fluid temperature inside the vapor chamber 10 and may generally be chosen according to the desired needs.

[0073] FIG. 2 shows a corner section cut of a vapor chamber 10. In FIG. 2, again, the evaporator 12, the condensers 16.sub.a, 16.sub.b and 16.sub.c and the air fins 20 are shown.

[0074] In more detail, according to FIG. 2, the internal structure is visible, showing evaporator wicks 24 which may be formed as a porous coating. Next to the evaporator wicks 24, condenser wicks 26 are shown. Both of the evaporator wicks 24 and the condenser wicks 26 may comprise capillary structures. The condenser wick 26 is found only on the vertical areas and potentially in the air fins 20 and is made of a very fine diameter, such as 50 micrometer, metallic mesh. It may be preferred to create the said wicks 24, 26 inside the inner volume using metal additive manufacturing technology (AM technology). By doing so, the potentially difficult and unreliable process of joining the vertical and horizontal parts of the above described capillary structure will be avoided. In this embodiment, the air fins 20 act at the same time as air turbulators and condensing sections.

[0075] FIG. 3 shows a front section cut of a vapor chamber 10 with the internal vapor and liquid circulation. In detail, the evaporator 12 as well as the condensers 16.sub.a, 16.sub.b, 16.sub.c are shown with their internal capillary structure.

[0076] The lines 28 show the positions of the condenser wicks 26. The purpose of the condenser wick 26 wick is to provide at the same time capillary pressure to ensure the fluid circulation and to enhance the heat transfer. For this reason, it might be preferred that the shown structure comprises a 3-dimensional capillary structure made, for example, of 100 microns large elements maximum. It may be formed by sintering of copper powder. Preferably, however, it may be formed by metallic additive manufacturing, which will allow to have it inside the hollow air fins 20 as well.

[0077] The arrows shown in the internal structure additionally indicate that the working fluid is evaporated, condensed in the air fins 20 and condensers 16.sub.a, 16.sub.b, 16.sub.c and guided back to the evaporator 12 in liquid form.

[0078] In FIG. 4, a condenser 16 is shown and in a cross section the air fins 20, wherein the arrows indicate the air flow through the air fins 20 and thus through the vapor chamber 10. In detail, the side section cut of the vapor chamber 10 shows the distinctive shape of the hollow air fins 20, which have a cross section of airfoils. It was found that these structures can improve the external heat transfer coefficient with air and at the same time reduce the pressure drop. Actually the ratio of heat transfer over the pressure drop can be increased by up to 50%. The hollow airfoil structure that houses a condenser wick 26 structure for condensation, allows the air fins 20 to have a uniform temperature, thus yielding a fin efficiency of 100%, compared to 50% in traditional heat sinks with metallic full bodied straight fin.

[0079] It can further be seen, that a plurality of air fins 20 is provided being arranged in a plurality of rows 30, the rows 30 being arranged one behind the other in the air flowing direction of the vapor chamber 10, and that the rows 30 are positioned relative to another in a staggered arrangement.

[0080] FIGS. 5 to 8 show different embodiments of the condensers 16, which may be realized in an especially defined and reliable manner by using additive manufacturing in order to further optimize the heat exchanger design.

[0081] With this regard, FIG. 5 shows an arrangement in which the condenser 16, such as the second condenser 16b or all condensers 16 present, is formed in a straight arrangement.

[0082] Further, FIGS. 6 to 8 show arrangements in which the condenser 16, such as the second condenser 16b or all condensers 16 present, is formed in at least one of a waved or dendritic arrangement. Under these figures, FIG. 6 shows a wave form of the condenser 16 and FIGS. 7 and 8 show different embodiments of tree-shaped forms.

[0083] FIGS. 5 to 8 show a side view onto a condenser and thus for example from one condenser 16 to a further condenser 16.

[0084] For instance, forming such as printing the condensers 16 in wave shape or further forms like described will intensify the heat dissipation on the air side by increasing the flow turbulence. Additive manufacturing also enables other solutions to be tested, such as tree-shaped heat pipes, like discussed. In addition, additive manufacturing allows for customization of the design for a specific application: the position of the condensers 16 can be adjusted for each particular design of power semiconductor devices, such as of IGBTs to enhance the heat transfer in areas with local hot spots 32.

[0085] In more detail, the structures as shown allow that an especially efficient cooling may be realized in regions in which thermal hot spots 32 arise. This may be due to the fact that the density of condensers 16 and air fins 20 may be increased in these regions.

[0086] This may be seen at a comparison of FIGS. 7 and 8, respectively. With this regard, FIG. 7 already shows an improved arrangement of the condenser 16 in which a tree-like structure is provided showing the advantages as described above. However, regarding FIG. 8, a further optimization is provided in that the condenser 16 with its air fins 20 is especially present in areas of thermal hot spots 32 like indicated by the arrows. Thus, the cooling effectivity is further enhanced.

[0087] FIG. 9 shows a diagram showing that the dominating thermal resistances (Rth, shown at the y-axis) are due to the air heat transfer and to the heat conduction through the air fins 20. At high heat loads (e.g. >1 kW, shown at the x-axis) their values can be two to three times higher than the vapor chamber condenser and evaporator thermal resistances.

[0088] Therefore the present invention gives a solution to reduce the air side thermal resistance of advanced vapor chambers 10 for heat sinks, for example.

[0089] Generally, the invention should not be limited to the embodiments as described. There can be two condensers 16, or even three or more than three, and the shape and arrangement of the air fins 20 as well as of the condensers 16 may be adapted to the desired needs. This invention is expected to work in any orientation (against gravity), thanks to the capillary pumping provided by the wick.

[0090] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to be disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting scope.

REFERENCE SIGNS LIST

[0091] 10 vapor chamber

[0092] 12 evaporator

[0093] 14 plane

[0094] 16 condenser

[0095] 18 plane

[0096] 20 air fin

[0097] 22 plane

[0098] 24 evaporator wick

[0099] 26 condenser wick

[0100] 28 line

[0101] 30 row

[0102] 32 thermal hot spot