Liquid-vapor phase change thermal interface material

Patent metadata

Field	Value
Publication number	US-10399190-B2
Application number	US-201414455580-A
Country	US
Kind code	B2
Filing date	Aug 8, 2014
Priority date	Aug 8, 2014
Publication date	Sep 3, 2019
Grant date	Sep 3, 2019

Abstract

An assembly for cooling a heat dissipating device reducing the thermal contact/interface resistance between a heatsink and a heat dissipating device includes: a heat dissipating device having a heat releasing surface; a heatsink having a heat absorbing surface; a gasket extending between the heat releasing surface and the heat absorbing surface to provide a sealed interstitial cavity; and a working fluid provided within the cavity. The working fluid has specific thermal properties that cause the fluid to (i) absorb latent heat and evaporate from a liquid to a vapor at the liquid surface in contact with the heat releasing surface during operation of the heat dissipating device and (ii) condense from the vapor back to the liquid when the vapor contacts the heat absorbing surface of the heatsink, thus releasing the latent heat from the vapor to the heatsink.

First claim

What is claimed is:

1. An assembly comprising:
a heat dissipating device having a casing with a heat releasing surface at which heat produced within or adjacent to the heat dissipating device accumulates and is removed from the heat dissipating device, the heat dissipating device having a plurality of screw bolt holes;
a heatsink having a base panel with an exterior-facing heat absorbing surface that absorbs the heat impacting the surface, the heat absorbing surface fixed in place across from the heat releasing surface by a separation distance, the heatsink having offsetting screw holes for insertion of screw bolts extending from the screw bolt holes of the heat dissipating device when the heat dissipating device and heatsink are assembled together with nuts screwed onto the screw bolts, the heat sink installed on top of the heat releasing surface of the heat dissipating device, wherein the heatsink is a cold plate having a second surface with a plurality of fins opposed to the heat absorbing surface, the second surface and plurality of fins cooled via an active air supply providing convection cooling using air movement generated by a fan;
a gasket having a closed perimeter and which extends upwards across the separation distance to form a volumetric space between the heat releasing surface and the heat absorbing surface, the gasket being sealably attached to both the heat releasing surface and the heat absorbing surface to provide a sealed interstitial cavity, wherein the gasket comprises a self-resealable material that enables use of a syringe to add and replenish a supply of a working fluid via physical injection of the working fluid; and
a groove created within at least one of the heat releasing surface or the heat absorbing surface, the groove having a perimeter shape that substantially mirrors a shape of the gasket, wherein one of a top and a bottom surface of the gasket proximate to the groove is inserted within the groove to provide a mechanical seal;
wherein the working fluid disposed within the sealed interstitial cavity and which has specific thermal properties that cause the working fluid to (i) absorb latent heat and evaporate from a liquid to a vapor when the liquid contacts the heat releasing surface during operation of the heat dissipating device, wherein the liquid evaporates to create bubbles of vapor particles that rises up through a liquid surface and become a part of the vapor within the sealed interstitial cavity, and (ii) condense from the vapor back to the liquid when the vapor contacts the heat absorbing surface of the heatsink, thus releasing the latent heat from the vapor to the heatsink, wherein the vapor condenses at the heat absorbing surface into liquid droplets that fall back into the liquid at a lower layer of the sealed interstitial cavity, and wherein the working fluid is replenished via use of the syringe having a needle that is inserted through the self-resealable material of the gasket into the sealed interstitial cavity, wherein the working fluid serves as a thermal interface material that is a working transport medium between the heat releasing surface and the heat absorbing surface, and wherein the sealed interstitial cavity is sealed and provides a partial vacuum such that the working fluid exhibits specific thermal properties of the working fluid when disposed in the partial vacuum.

2. The assembly of claim 1 , wherein the gasket is sealably affixed to at least one of the heat releasing surface and the heat absorbing surface and extends away from the at least one of the heat releasing surface or the heat absorbing surface to support direct insertion of the gasket into the groove when the the heat releasing surface and the heat absorbing surface are brought together.

3. The assembly of claim 1 , wherein the working fluid is water and water vapor.

4. The assembly of claim 1 , wherein the heat dissipating device comprises a central processing unit (CPU).

5. The assembly of claim 1 , wherein the needle of the syringe is inserted into the gasket, whereby the gasket is pierced by the needle, and the working fluid is then injected into the sealed interstitial cavity from the syringe until sufficient amounts of the liquid is inserted, as determined via empirical analysis using a volume of the sealed interstitial cavity as one variable and a rate of heat exchange as another variable.

6. The assembly of claim 1 , wherein during the replenishment of the working fluid, the needle creates a small bore in the gasket and the self-resealable material of the gasket at which the needle is inserted is pliable and seals back into place once the needle is removed.

7. The assembly of claim 1 , wherein the sealed interstitial cavity comprises a partial vacuum, which causes the working fluid to be at a saturation point and allows for easier boiling of the working fluid whenever the heat is produced at the heat releasing surface of the heat dissipating device, the heat being applied to the working fluid at the saturation point that causes the working fluid to undergo a liquid-to-gas phase change.

8. An information handling system having at least one component requiring active heat dissipation, the information handling system comprising:
a heat dissipating device having a casing with a heat releasing surface at which heat produced within or adjacent to the heat dissipating device accumulates and is removed from the heat dissipating device, the heat dissipating device having a plurality of screw bolt holes;
a heatsink having a base panel with an exterior-facing heat absorbing surface that absorbs heat impacting the surface, the heat absorbing surface fixed in place across from the heat releasing surface by a separation distance, the heatsink having offsetting screw holes for insertion of screw bolts extending from the screw bolt holes of the heat dissipating device when the components are assembled together with nuts screwed onto the screw bolts, the heatsink installed on top of the heat releasing surface of the heat dissipating device, wherein the heatsink is a cold plate having a second surface with a plurality of fins opposed to the heat absorbing surface, the second surface and plurality of fins cooled via an active air supply providing convection cooling using air movement generated by at least one air moving device;
a gasket having a closed perimeter and which extends upwards across the separation distance to form a volumetric space between the heat releasing surface and the heat absorbing surface, the gasket being sealably attached to both the heat releasing surface and the heat absorbing surface to provide a sealed interstitial cavity, wherein the gasket comprises a self-resealable material that enables use of a syringe to add and replenish a supply of working fluid via physical injection of the working fluid;
a groove created within at least one of the heat releasing surface or the heat absorbing surface, the groove having a perimeter shape that substantially mirrors a shape of the gasket, wherein one of a top and a bottom surface of the gasket proximate to the groove is inserted within the groove to provide a mechanical seal; and
a working fluid disposed within the sealed interstitial cavity and which has specific thermal properties that cause the fluid to (i) absorb latent heat and evaporate from a liquid to a vapor when the liquid contacts the heat releasing surface during operation of the heat dissipating device, wherein the liquid evaporates to create bubbles of vapor particles that rises up through a liquid surface and become a part of gas within the sealed interstitial cavity, and (ii) condense from the vapor back to the liquid when the vapor contacts the heat absorbing surface of the heatsink, thus releasing the latent heat from the vapor

Assignees

• Dell Products Lp

Inventors

• North Travis C
• Shelnutt Austin Michael
• Helberg Chris
• Salas Rene Jason

Classifications

• H10W40/73

  for cooling by change of state · CPC title

• G06F2200/201

  Cooling arrangements using cooling fluid · CPC title

• G06F1/20 Primary

  Cooling means · CPC title

• B23P15/26 Primary

  heat exchangers {or the like (making heat exchangers by methods covered by other subclasses B21D53/02)} · CPC title

• H01L23/427

  Electricity · mapped topic