COOLING OF ELECTRONIC COMPONENTS WITH AN ELECTROHYDRODYNAMIC FLOW UNIT

Abstract

An arrangement for thermal management is disclosed, wherein a heat generating component is arranged within an enclosure, defined by an enclosure wall and in thermal contact with a thermal management fluid. The arrangement comprises an electrohydrodynamic flow unit, comprising a first and a second electrode, for controlling the flow of fluid within the enclosure.

Claims

1.-15. (canceled)

16. An arrangement for thermal management of a heat generating component, wherein the heat generating component is arranged within an enclosure and is in thermal contact with a dielectric liquid, the arrangement comprising: a first electrohydrodynamic (EHD) flow unit arranged within the enclosure, wherein the first EHD flow unit comprises a first electrode and a second electrode arranged offset from the first electrode, and wherein the first EHD flow unit controls a flow of the dielectric liquid between the first electrode and the second electrode; and an enclosure wall at least partly defining the enclosure, wherein the enclosure wall is attached to one of the heat generating component and an interposer carrying the heat generating component, thereby defining the enclosure.

17. The arrangement of claim 16, further comprising a second EHD flow unit arranged within the enclosure, the second EHD flow unit comprising a first electrode and a second electrode arranged offset from the first electrode, wherein: the first EDH flow unit directs the flow towards the heat generating component; and the second EDH flow unit directs the flow away from the heat generating component.

18. The arrangement of claim 16, wherein at least one of the first and second electrodes is arranged on the heat generating component.

19. The arrangement of claim 18, wherein the at least one of the first and second electrodes is formed by an electrically conductive layer provided on a surface of the heat generating component.

20. The arrangement of claim 19, wherein the at least one of the first and second electrodes is formed by a graphene layer provided on the heat generating component.

21. The arrangement of claim 16, wherein at least one of the first and second electrodes is arranged on an inside of the enclosure wall.

22. The arrangement of claim 18, wherein at least one of the first and second electrodes is arranged on an inside of the enclosure wall.

23. The arrangement of claim 17, wherein: the second electrodes of the first and second EDH flow units operate as collector electrodes and are arranged on the heat generating component and an inside of the enclosure wall; the first electrode of the first EDH flow unit forms an emitter electrode arranged closer to the collector electrode arranged on the heat generating component than to the collector electrode arranged on the inside of the enclosure wall; and the first electrode of the second EDH flow unit forms an emitter electrode arranged closer to the collector electrode arranged on the inside of the enclosure wall than to the collector electrode arranged on the heat generating component.

24. The arrangement of claim 16, further comprising a heat exchanger in thermal contact with the enclosure wall.

25. The arrangement of claim 24, further comprising a thermal interface material (TIM) arranged between the heat exchanger and an outside of the enclosure wall.

26. The arrangement of claim 24, wherein the TIM comprises graphene.

27. A device comprising: the arrangement of claim 16; and a plurality of heat generating components arranged within the enclosure.

28. A method of thermal management of a heat generating component, comprising: placing the heat generating component within an enclosure; providing a dielectric liquid in thermal contact with the heat generating component; placing a first electrohydrodynamic (EHD) flow unit within the enclosure, wherein the first EHD flow unit comprises a first electrode and a second electrode arranged offset from the first electrode, and wherein the first EHD flow unit controls a flow of the dielectric liquid between the first electrode and the second electrode; and providing an enclosure wall to at least partly define the enclosure, wherein the enclosure wall is attached to one of the heat generating component and an interposer carrying the heat generating component, thereby defining the enclosure.

29. The method of claim 28, further comprising directing the dielectric liquid flow towards the heat generating component with the first EDH flow unit and directing the dielectric liquid flow away from the heat generating component with a second EDH flow unit.

30. A device, comprising: an enclosure; a heat generating component disposed within the enclosure, directly, or indirectly via an interposer, attached to an enclosure wall, and in thermal contact with a dielectric liquid; and a first electrohydrodynamic (EHD) flow unit disposed within the enclosure for controlling a flow of the dielectric liquid between a first electrode and a second electrode first EDH flow unit.

31. The device of claim 30, wherein at least one of the first and second electrodes is arranged on the heat generating component.

32. The device of claim 32, wherein the at least one of the first and second electrodes is formed by an electrically conductive layer provided on a surface of the heat generating component.

33. The device of claim 32, wherein the at least one of the first and second electrodes is formed by a graphene layer provided on the heat generating component.

34. The device of claim 30, further comprising a second EHD flow unit arranged within the enclosure, the second EHD flow unit comprising a first electrode and a second electrode, wherein: the first EDH flow unit directs the dielectric liquid flow towards the heat generating component; and the second EDH flow unit directs the dielectric liquid flow away from the heat generating component.

35. The device of claim 34, wherein: the second electrodes of the first and second EDH flow units operate as collector electrodes and are arranged on the heat generating component and an inside of the enclosure wall; the first electrode of the first EDH flow unit forms an emitter electrode arranged closer to the collector electrode arranged on the heat generating component than to the collector electrode arranged on the inside of the enclosure wall; and the first electrode of the second EDH flow unit forms an emitter electrode arranged closer to the collector electrode arranged on the inside of the enclosure wall than to the collector electrode arranged on the heat generating component.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0027] The above, as well as additional objects, features and advantages of the present invention, will be better understood through the following illustrative and non-limiting detailed description of embodiments of the present invention. Reference will be made to the appended drawings, on which:

[0028] FIG. 1 is a schematic cross sectional view of a thermal management system comprising an enclosure, a heat generating component and a plurality of flow units arranged within the enclosure, according to some embodiments of the present invention;

[0029] FIGS. 2a, 2b and 2c are schematic cross sectional views of different electrode configurations in flow units;

[0030] FIGS. 3a and 3b display exemplary configurations of flow units in relation to the heat generating component;

[0031] FIG. 4 is a schematic view of a thermal management system, with increased electrode surface according to one embodiment;

[0032] FIG. 5 is a top view of an embodiment of a heat generating component provided with electrodes.

[0033] All the figures are schematic, generally not to scale, and generally only show parts which are necessary in order to elucidate the invention, whereas other parts may be omitted or merely suggested.

DETAILED DESCRIPTION

[0034] FIG. 1 shows a thermal management system 100 comprising a heat generating component 110 attached to an interposer 150, and an enclosure wall defining an enclosure 120. The heat generating component 110 may comprise, for example, flip chip as shown in the present figure, a wire bonded component, or a tape automated bonded device being e.g. a processor. In some examples, the heat generating component may be a capacitor or a battery. Within the enclosure 120, a thermal management fluid may be provided. The thermal management fluid may be a cooling substance, for example comprising dielectric gas, boiling liquid, or a dielectric liquid 130. In case the thermal management fluid is a utilised as a boiling liquid, the enclosure wall may have a portion, such as a ceiling, forming a porous or capillary structure for allowing gas to escape the enclosure.

[0035] The embodiment displayed suggests a closed system where the dielectric fluid 130 is circulated within the enclosure 120, whilst other embodiments may comprise inlets and outlets allowing fluid to circulate out of, and in to, the enclosure 130.

[0036] Within the enclosure 130, the fluid may be caused to flow using flow units 140,141,142,143. A flow unit 140 may comprise a first and a second electrode, and a flow F may be generated by applying a voltage over the electrodes. Decreasing or terminating the electric field between the electrodes may cause the flow F to decrease or stop, and the cooling effect may through this be decreased to achieve an optimal temperature for the heat generating component 110. In this embodiment, the flow units 140-143 are located in between the heat generating component 110 and the enclosure wall 121. It will however be appreciated that other embodiments may comprise flow units located around and/or under the heat generating component 110. In some examples, one or several flow units 110 may be arranged between the solder bumps of the heat generating component 110 so as to further improve the flow of fluid under the component 110.

[0037] In the present embodiment, the flow units are positioned such that every other flow unit 140, 142 create a flow F1 towards the heat generating unit 110 and the remaining flow units 141,143 create a fluid flow in a direction F2 away from the component 110. Further, a heat exchanger 160 may be arranged in thermal contact with the enclosure wall 121. The heat exchanger 160 may form a heat pipe, heat sink or similar structures for transferring heat energy away from the fluid. Other embodiments may provide the heat exchanger 160 on the inside of the wall and connected to external pump arrangements.

[0038] FIGS. 2a, 2b and 2c show embodiments of a thermal management system 100 which may be similarly configured as the arrangement discussed in connection with FIG. 1. In these examples, the flow units 140 comprise a first electrode 140a, which may be referred to as an emitter electrode, and a second electrode 140b, which may be referred to as the collector electrode. In the shown arrangements, all flow units may be submerged in dielectric liquid 130. As illustrated, the enclosure 120 may be defined by the enclosure wall 121 and the heat generating component 110, onto which the enclosure wall 121 may be sealingly attached.

[0039] FIG. 2a shows a first flow unit 140 comprising the first electrode 140a and second electrode 140b placed together in one unit. A voltage applied to the electrodes 140a and 140b may cause the dielectric fluid flowing in the F direction, towards a heat generating component 110.

[0040] FIG. 2b displays two flow units 140, 141 (indicated by dashed lines), wherein the first electrodes 140a, 141a of the respective flow units 140, 141 are separated from the second electrodes 140/141b, and the resulting flow F directed towards the component. In this embodiment, the first, emitter, electrodes are arranged between the component 110 and the enclosure wall 121, whilst the second, collector, electrode 140/141b is located on the surface of the heat generating component 110. With a voltage applied, the first electrodes 140a, 141a may create a flow F of dielectric fluid toward the heat generating component 110. Furthermore, in FIG. 2b, the flow units 140 and 141 are shown to have one shared second electrode 140/141b, this meaning the second electrode 140/141b may function as a collector for multiple first electrodes 140a,141a.

[0041] In FIG. 2c, the second electrodes 140b, 141b are provided on both the top and the bottom of the figure, i.e., both on the inside or ceiling of the enclosure wall 121 and on the top surface of the heat generating component 110. The first electrodes 140a, 141a may be located in between the ceiling of the enclosure wall 121 and the top surface of the component 110. Flow unit 140 is directing a flow F1 downwards, i.e., towards the component 110, whilst 141 is directing a flow F2 upwards, towards the ceiling of the enclosure.

[0042] The different directions of the flow F1, F2 may be achieved due to at least two different, independent mechanisms. The first mechanism is the electron emitting structures, illustrated by the first electrode 140a which is shown to have surface structures that facilitates electron emission. In this embodiment they are depicted as tips or needles pointing in a downward direction and determining the emitting direction of the electrode 140a.

[0043] The second mechanism is the relative distance between the electrodes. The first electrode 141a has flow direction determined by the distance to the second electrode 140b, 141b. The shortest distance between first electrode 140a, 141a and second electrode 140b, 141b defines the direction of the flow F. In FIG. 2c, electrode 141a is located closer to the collector electrode 141b arranged on the enclosure ceiling than to the collector electrode 140b arranged on the component, and therefore form flow unit 141 directing the flow away from the component.

[0044] FIGS. 3a and 3b show embodiments of a thermal management system 100, which may be similarly configured as the embodiments shown in the previous figures. In the present examples, the flow unit placements represent different alternatives for directing the flow F of thermal management fluid 130 towards and away from the heat generating component 110.

[0045] FIG. 3a shows an embodiment in which electrodes 140a-142b are attached on the inner surface of the enclosure wall 121, and on the heat generating component 110. In this embodiment both the wall section 121 and the component 110 are provided with both first electrodes 140a-142a and second electrodes 140b-142b. The electrodes on the heat generating component 110 may comprise a second electrode 141b in the middle and two first electrodes 140a, 142a on the sides of the first electrode 141b. The opposite configuration is utilized on the enclosure wall 121, wherein second electrodes 140b,142b are arranged on the sides and the first electrode 141a in the middle. As a result, three separate flow units are formed. This may result in flow a F2 towards the heat generating component as well as flows F1 away from it.

[0046] FIG. 3b shows an embodiment in which the flow F is directed parallel to the heat generating component 110. This embodiment displays a variation which may be suitable if the upstream side of the component 110 is in greater need of cooling than the downstream side. This figure depicts the electrodes 140a,140b located on the sides of the component and may be attached to the inner wall of the enclosure. The first electrode 140a may direct the flow towards the component 110 and the second electrode 140b may direct the flow away from it. Similarly, the parallel flow direction F could as well be obtained with electrodes placed on the heat generating component.

[0047] FIG. 4 is a schematic representation of a thermal management system 100, which may be configured in a similar way as any of the previously described embodiments. In the FIG. 4, the enclosure wall 121 may be configured to increase the efficiency of the flow units. This may for example be achieved by providing a rough shape of the part of the enclosure wall 121 comprising the first electrode 140a so as to increase the surface area of said electrode 140a. This increase could potentially facilitate flow F1. Furthermore, specific shapes, such as peaks, could further facilitate flow. In this specific embodiment, the heat generating component 110 comprises an entire wall section of the enclosure, and this heat generating device 110 may function as both a first electrode 141a and a second electrode 140b. Further, a heat exchanger 160 may be arranged in thermal contact with the enclosure wall 121. The heat exchanger 160 may for example be a heat pipe or heat sink for dissipating thermal energy from the enclosure, and thus indirectly from the heat generating device. Between the enclosure wall 121 and the heat exchanger 160 may, in this embodiment, a thermal interface material 170, for example graphene, be arranged for increased heat transfer.

[0048] FIG. 5 shows a top view of a heat generating component 110 to be cooled. The present component 110 may form part of an embodiment similar to the ones shown in the previous figures. In this instance the component 110 may be utilized as part of multiple flow units. On the component is an exemplary layout of first electrodes 141a-144a and a second electrode 140b illustrated. In this embodiment, the second, collector, electrode 140b is placed in the middle of the component whilst the emitting first electrodes 141a-144a are placed along the sides of the component. This could for example benefit cooling of the central area of the heat generating component and could create a tubular flow of thermal management fluid.