Flexible Graphite Thermal Management Devices

a graphite thermal management and flexible technology, applied in the direction of indirect heat exchangers, heat exchange apparatus, light and heating apparatus, etc., can solve the problems of unusability in some situations, unsatisfactory conventional heat pipe structure, extreme critical factors of weight and space, etc., to achieve satisfactory thermal conductivity, excellent weight, and acceptable rigidity

US20090032227A1Inactive Publication Date: 2009-02-05GRAFTECH INT HLDG INC
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Patent Information

Authority / Receiving Office
US · United States
Current Assignee / Owner
Publication Date
2009-02-05
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention provides to thermal management devices constructed from flexible graphite. In one embodiment, the thermal management device includes a wick structure inside a shell. In certain preferred embodiments, the wick structure is composed of a mass of expanded graphite. In a another embodiment, the shell of the device includes flexible graphite and an optional wick structure. In certain preferred embodiments, the flexible graphite shell is fluid impermeable. The invention further includes methods of making the aforementioned thermal management devices.
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Description

FIELD OF THE INVENTION

[0001] The invention relates to thermal management devices, and more particularly, to such devices, which include flexible graphite and methods of making such devices.BACKGROUND OF THE INVENTION

[0002] Thermal management devices, such as heat pipes, are devices which are known in the art of heat transfer. A heat pipe is essentially a closed system of heat transfer in which a small amount of liquid within a sealed and evacuated enclosure is cycled through an evaporation and condensation cycle. Heat entering the enclosure at one location on the casing evaporates liquid at that location, producing vapor, which moves to a cooler location on the casing where it is condensed. The movement of the vapor is motivated by a small vapor pressure differential between the evaporator and the condenser locations. The heat transfer is accomplished when the heat of vaporization, which produces the vapor, is essentially moved with the vapor to the condenser location where it is give...

Examples

Embodiment Construction

[0018]Graphites may be characterized as laminated structures of carbon, that is, structures consisting of superposed layers or laminae of carbon atoms joined together by weak van der Waals forces. In considering the graphite structure, two axes or directions are usually noted, to with, the “c” axis or direction and the “a” axes or directions. For simplicity, the “c” axis or direction may be considered as the direction perpendicular to the carbon layers. The “a” axes or directions may be considered as the directions parallel to the carbon layers or the directions perpendicular to the “c” direction. The graphites suitable for manufacturing flexible graphite sheets possess a very high degree of orientation.

[0019]As noted above, the bonding forces holding the parallel layers of carbon atoms together are only weak van der Waals forces. Natural graphites can be treated so that the spacing between the superposed carbon layers or laminae can be appreciably opened up so as to provide a marke...