Three-dimensional mesh and housing for thermal ground plane

Abstract

The invention discloses a three-dimensional mesh and a three-dimensional housing for a thermal ground plane. The three-dimensional mesh and the three-dimensional shell may establish a vapor core having a structural elastic positive or negative pressure differential between the vapor space and external conditions. The invention discloses a thermal grounding plane, which comprises a first shell and a second shell, wherein the first shell and the second shell are substantially planar. The outer periphery of the first housing and the outer periphery of the second housing are joined together to form a gas-tight closure. The second housing is deformable to form a vapor support structure within the thermal ground plane that includes a plurality of deformed portions (or rough cylinders). A working fluid may be disposed within the first housing and the second housing. A permeable capillary structure may also be disposed on an inner surface of the first housing and / or on the second housing for fluid delivery disposed between the first housing and the second housing.

Description

Background Technology

[0001] A thermal ground plane, also known as a vapor chamber, provides a passive thermal management solution through a closed microfluidic system. An advanced thermal ground plane may include a mesh wick permeated with a liquid. When heat is applied to the system, the liquid evaporates and generates a warm vapor within a vapor channel. This warm vapor has an increased pressure due to the saturation pressure effect, and this increased pressure induces internal convection currents in the gas phase. This convection currents heat the entire gas phase until the temperature becomes nearly uniform. The vapor condenses in cooler regions, and the condensed liquid is drawn back through the capillary force generated by the capillary structure to the heat source, thus allowing the thermal ground plane to dissipate heat. By using phase change and internal convection, thermal ground planes can achieve effective thermal conductivity far exceeding that of solid radiators such as copper or graphite. Summary of the Invention

[0002] This invention discloses a thermal grounding plane that can be used in a variety of applications, such as space applications, mobile electronic devices, and high-power electronic devices.

[0003] This invention discloses a thermal grounding plane comprising a substantially planar first housing and a second housing. The outer peripheries of the first housing and the second housing are joined together to form a hermetically sealed enclosure. The second housing is deformable to form a vapor support structure comprising a plurality of deformable portions (or roughened columns) within the thermal grounding plane. A working fluid may be disposed within the first housing and the second housing. A permeable capillary structure may also be disposed on an inner surface of the first housing for fluid transport between the first housing and the second housing.

[0004] In one embodiment of the aforementioned thermal grounding plane, the first housing and / or the second housing comprises at least one of copper, aluminum, and stainless steel. In another embodiment of the aforementioned thermal grounding plane, the first housing and / or the second housing comprises a flexible laminate having multiple layers, wherein at least one layer of the multiple layers comprises a polymer. For example, the second housing has a thickness of less than 0.036 mm.

[0005] In another embodiment of the aforementioned thermal grounding plane, the permeable capillary structure is coupled to multiple portions of both the first housing and the second housing.

[0006] In one embodiment of the aforementioned thermally grounded plane, the second capillary structure is disposed on an inner surface of the second housing. In another embodiment, multiple portions of the second capillary structure are engageable with the second housing, while other portions of the second capillary structure are engaged with the first capillary structure. In yet another embodiment, the permeable capillary structure is flattened and deformed to form multiple deformations for liquid transport.

[0007] In one embodiment of the thermal grounding plane described above, the thermal grounding plane may include a plurality of flexures configured to connect to a substrate and allow relative movement of a plurality of portions of the thermal grounding plane.

[0008] The present invention further discloses an embodiment of a thermal grounding plane. The thermal grounding plane includes a first housing and a first capillary structure engaged with the first housing. The first capillary structure can be used for liquid transport related to evaporation or boiling. The thermal grounding plane may include a second housing and a second capillary structure engaged with the second housing. The second capillary structure can be used for liquid transport related to condensation. The outer peripheries of the first housing and the second housing may be engaged with each other to form a hermetically sealed enclosure. A liquid supply structure may be included in contact with the first and second capillary structures. The liquid supply structure can be used for liquid transport. The liquid supply structure may have a structure configured to allow vertical liquid transport between the first and second capillary structures and horizontal liquid transport along the liquid supply structure. A working fluid may be disposed within the first and second housings. For example, the liquid supply structure may include a mesh selected from the group consisting of copper mesh, stainless steel mesh, and polymer mesh.

[0009] In one embodiment of the aforementioned thermal grounding plane, the liquid supply structure may include multiple mesh layers.

[0010] As another embodiment, the liquid supply structure may have a shape selected from a group consisting of a wave shape, a triangular shape, a trapezoidal shape, and an asymmetrical wave shape.

[0011] In one embodiment of the thermal grounding plane described above, a vapor support structure may be included, disposed between the first housing and the second housing. For example, the vapor support structure and the liquid supply structure may be disposed within the space of the thermal grounding plane.

[0012] In one embodiment of the aforementioned thermal grounding plane, the second capillary structure includes a plurality of mesh layers. For example, the plurality of mesh layers may include at least a first mesh layer and a second mesh layer, wherein the pore size of the first mesh layer is larger than the pore size of the second mesh layer, and the first mesh layer is disposed between the second housing and the second mesh layer.

[0013] In one embodiment of the aforementioned thermal grounding plane, the first capillary structure includes a plurality of mesh layers. For example, the plurality of mesh layers includes at least one first mesh layer and one second mesh layer, the pore size of the first mesh layer being larger than the pore size of the second mesh layer, and the second mesh layer being disposed between the first housing and the first mesh layer. For example, the peripheries of the plurality of mesh layers may be flattened to reduce the pore size, small enough to prevent vapor from seeping into the liquid transport channel. Attached Figure Description

[0014] Figure 1A This is a side view schematic diagram of an internal structure of a thermally grounded plane according to some embodiments.

[0015] Figure 2A This is a side view of a thermally grounded plane having a deformable top shell, a bottom shell, and a capillary structure.

[0016] Figure 2B This is a side view of a thermally grounded plane having a top capillary structure disposed on the inner surface of the top housing.

[0017] Figure 3A This is a side view of a thermally grounded plane having an internal joint located between the top and bottom housings.

[0018] Figure 3B This is a side view of the thermally grounded plane. In this embodiment, the capillary structure includes a wall formed at the wick perimeter of the capillary structure.

[0019] Figure 4A A side view of a thermally grounded plane having a tiled wick and a vapor support structure configured within a top shell and a bottom shell.

[0020] Figure 4B This is a side view of a tiled mesh, where each tile comprises multiple layers of mesh with very small openings on the outer layer to prevent vapor from seeping into the fluid channels along the tiled mesh.

[0021] Figure 4C This is a top view of a brick-like mesh structure.

[0022] Figure 5A This is a side view of a thermally grounded plane having an internal connection between a deformable mesh for steam transport and a capillary structure. In this embodiment, the top housing is substantially planar (e.g., undeformed).

[0023] Figure 5B This is a side view of a thermally grounded plane having a bottom deformable mesh for capillary structures, the bottom deformable mesh including a flattened area as a wall to protect the liquid channels beneath the capillary structures from vapor infiltration.

[0024] Figure 6 A side view of a thermally grounded plane in which multiple openings are left in the mesh due to the removal or cutting away of multiple parts of the vapor support structure.

[0025] Figure 7A Shows a top view of a foldable thermally grounded plane in a static state.

[0026] Figure 7B This shows a foldable thermal grounding plane in a stretched state.

[0027] Figure 8A This is a side view of a thermally grounded plane having a top condensing capillary structure and a bottom evaporating / boiling capillary structure connected by a liquid supply structure.

[0028] Figure 8B This is a cut top view of a thermally grounded plane that integrates multiple liquid supply structures and multiple vapor support structures.

[0029] Figure 9A This illustrates an embodiment of a triangular liquid supply structure within a thermally grounded plane.

[0030] Figure 9B An embodiment of an asymmetric wave-shaped liquid supply structure in a thermally grounded plane is shown.

[0031] Figure 10A This illustrates an embodiment of a deformable mesh used in a condensation capillary structure.

[0032] Figure 10B This illustrates an embodiment of a multilayer mesh used for a condensation capillary structure.

[0033] Figure 11 This illustrates an embodiment of a multilayer network used for an evaporation / boiling capillary structure.

[0034] Figure 12 This is a side view of a thermally grounded plane that includes two types of steam support structures.

[0035] Figure 13 This is a side view schematic diagram of a thermally grounded plane including a deformable mesh that serves as a liquid supply and a vapor support structure. Detailed Implementation

[0036] This article discloses three-dimensional meshes and housings for advanced thermal grounding planes. A thermal grounding plane, also known as a vapor chamber, is a passive thermal management solution for closed microfluidic systems. A thermal grounding plane typically comprises a capillary structure permeated with a liquid. When heat is applied to the system, the liquid evaporates and generates a warm vapor within a vapor chamber. Due to the saturation pressure effect, the warm vapor has increased pressure, which induces internal convection currents in the gas phase. This convection heats the entire gas phase until the temperature becomes nearly uniform. The vapor condenses in cooler regions, and the condensed liquid is drawn back through the capillary structure to the heat source by capillary forces generated by the capillary structure. Thus, the thermal grounding plane dissipates heat. By utilizing phase change and internal convection, a thermal grounding plane can achieve an effective thermal conductivity far exceeding that of solid radiators such as copper or graphite.

[0037] The components of a thermal ground plane, as shown in Figure 1, include a housing, capillary structure, vapor space, and encapsulated fluid. In most thermal ground planes, a mesh is used as the capillary structure. To meet the challenging requirements of new applications for thermal ground planes, improvements to the mesh and housing are useful. One major improvement is the application of a three-dimensional configuration, which can provide characteristics far exceeding those achievable in two dimensions.

[0038] The embodiments of the thermal grounding plane described herein and shown in any figures are not drawn to scale, and some features may not be proportional to others. Some features shown in the figures may be exaggerated for illustrative purposes.

[0039] Figure 1A This is a schematic diagram of a thermal grounding plane 100 according to certain embodiments. In this embodiment, the thermal grounding plane 100 includes a top housing 110, a bottom housing 115, a capillary structure 120 (or a liquid structure), and / or a vapor structure 125. For example, the thermal grounding plane 100 can achieve heat transfer between the evaporation region 130 and the condensation region 135 through the evaporation, vapor transport, condensation, and liquid reflux of water or other cooling media. The structure and / or characteristics of the thermal grounding plane 100 can be applied to any embodiment or example described herein.

[0040] For example, the top housing 110 may include copper, stainless steel, aluminum, polymer, atomic layer deposition (ALD) coated polymer, flexible copper foil substrate (FCCL), polymer-coated copper, copper-clad polyimide film (Kapton), etc. For example, the top housing 110 and the bottom housing 115 may be sealed together using solder, laser welding, ultrasonic welding, electrostatic welding, or thermocompression bonding (e.g., diffusion bonding) or a sealant. For example, the top housing 110 and the bottom housing 115 may include the same or different materials.

[0041] For example, the top housing 110 and / or the bottom housing 115 may include a flexible copper foil substrate having at least three layers: a first copper layer (e.g., 12 micrometers thick), a second polyimide layer (e.g., 12 micrometers thick), and a third copper layer (e.g., 12 micrometers thick). Each of these three layers may have a thickness equal to or less than 50, 20, 15, 12, 10, or 8 micrometers. For example, polyimide may be sandwiched between two copper layers. For example, the copper layers on the top housing and / or the bottom housing may be replaced with ALD nanoscale layers, such as Al2O3, TiO2, SiO2, etc., to achieve an extremely thin housing (e.g., less than about 10 micrometers thick).

[0042] The evaporation zone 130 and the condensation zone 135 can both be disposed on the top housing 110 or the bottom housing 115. Alternatively, the evaporation zone 130 and the condensation zone 135 can be disposed on different layers of the top housing 110 and the bottom housing 115.

[0043] In some embodiments, the vapor structure 125 may be formed from a top shell 110 that has been deformed into various geometries. This may improve structural reliability, heat transfer, flow permeability, capillary radius, thermal conductivity, effective heat transfer coefficient for evaporation, and / or effective heat transfer coefficient for condensation under the pressure difference between the vapor pressure inside the thermal ground plane and the ambient pressure outside the thermal ground plane during folding and unfolding. In some embodiments, the initial structure may include a multilayer mesh.

[0044] In some embodiments, the outer periphery of the top housing 110 and the outer periphery of the bottom housing 115 may be sealed at the perimeter bond 140, for example, by using any number of techniques to achieve an hermetical seal.

[0045] The various embodiments described herein include a mesh. Figure 1B This is an embodiment of a woven mesh. The term "mesh" as used herein may, in some embodiments, include a mesh having a similar structure to... Figure 1B The mesh structure shown contains multiple threads woven together to create a material with multiple pores. Various other types of meshes can also be used.

[0046] For example, the mesh may include copper and / or stainless steel. For example, the mesh may include a material with pores having a size of about 10 to 200 µm. For example, a nonporous mesh may include a material with pores that may have a size of about 0.2 to 10 µm. The mesh may be characterized by a pore size and / or a mesh number. The pore size represents the average size of the pores within the mesh. For example, the average pore size in a mesh may be 0.05 millimeters (mm). The mesh number represents the average number of wires or openings per inch. For example, a mesh with a mesh number of #400 has 400 wires or openings per inch.

[0047] For example, the mesh may comprise a material containing metals and / or polymers. For example, a deformable corrugated mesh may be highly stretchable, for example, stretchable without plastic deformation, which may, for example, reduce stress during folding and / or prevent wrinkle formation and obstruction of vapor flow. For example, the mesh may be conductive and / or may be coated with a dielectric material, for example, to prevent material plating into the pores away from the anchors. For example, the pores in the mesh may be made of polymers, ceramics, other electrically insulating materials, or conductive materials and / or may be covered by an electrically insulating layer. For example, the mesh may comprise woven wires, non-woven wires, or porous planar media. For example, the mesh may comprise an ALD-coated polymer that does not contain any metals. The ALD coating may be replaced by other thin-film coatings. For example, the mesh may comprise a copper-clad-polyimide laminate material. For example, the mesh may include a copper mesh or a non-copper mesh, such as a polymer mesh or a stainless steel mesh. For example, the mesh may be encapsulated with a hydrophilic and corrosion-resistant hermetic seal. For example, the mesh may include any woven or non-woven material.

[0048] For example, the mesh can have a thickness of about 10 µm to about 1,000 µm. For example, a woven mesh can have a thickness of about 1,000, 500, 125, 100, 75, 50, or 25 µm. A porous mesh (e.g., a nanoporous mesh and / or a nonwoven mesh) can have a thickness of about 5, 10, 15, 20, or 25 µm. For example, the mesh may include a metal foam.

[0049] The various thermal grounding planes described herein may include an array of pillars, which may include any or all of the following characteristics. For example, an array of pillars may include pillars in a uniform or non-uniform distribution pattern. For example, an array of pillars may include pillars composed of a polymer. For example, an array of pillars may include pillars composed of a metal (such as copper or stainless steel). For example, an array of pillars may include pillars coated with a coating, such as a ceramic (such as Al2O3, TiO2, SiO2, etc.) or a nanotextured coating. This coating may be applied by defect-free ALD, low-defect-density ALD, chemical vapor deposition (CVD), molecular layer deposition (MLD), or other nanoscale or microscale coating processes.

[0050] For example, an array of multiple columns can be a pseudo-rectangular array, a pseudo-hexagonal array, or a random array. For example, an array of multiple columns can have a center-to-center pitch that remains constant throughout the array. For example, an array of multiple columns can include multiple columns with variable diameters and / or heights. For example, an array of multiple columns can have a low density (e.g., larger spacing) at the condenser, a higher density at the evaporator, and / or a gradually changing density between the condenser and the evaporator.

[0051] The various embodiments described herein include an array of micropillars. For example, an array of micropillars may be configured on an array of multiple pillars, wherein the array of multiple pillars is larger than the array of micropillars. For example, an array of micropillars may include a deformable mesh or a porous material, wherein the pore size of the material is substantially smaller than the gap between the pillars. For example, an array of micropillars may include nano-wire bundles, sintered particles, template-grown pillars, inverse opal structures, etc. For example, an array of micropillars may include solid pillars, which can facilitate thermal conduction along the length direction, and the outer regions of the array of micropillars may be porous to facilitate capillary action.

[0052] The various embodiments described herein may include internal thermally grounded plane structures composed of polymers. For example, these thermally grounded plane structures may include top shells, bottom shells, meshes, arrays of multiple pillars, arteries, capillary structures, vapor structures, etc. For example, the polymer structure may be coated with metals, defect-free ALD, low-defect-density ALD, CVD, MLD, or other nanoscale coating processes.

[0053] The thermal grounding plane disclosed in this paper can be used in any number of applications, such as space systems. For example, for space systems, a thermal grounding plane can be designed to be ultra-lightweight and high-performance, where there is a positive or negative pressure difference between the vapor space and external conditions.

[0054] Figure 2A This is a side view of a thermally grounded plane 200 having a deformable top housing 210, a bottom housing 215, and a capillary structure 120. The top housing 210 and bottom housing 215 may surround the capillary structure 120 and may be sealed at a peripheral joint 140 at the outer periphery of the top housing 210 and bottom housing 215. The top housing 210 and bottom housing 215 may include any number of layers. In this embodiment, three layers are shown, and may include a laminate of copper, polyimide, and copper. Various other layers may be included in the top housing 210 and / or bottom housing 215.

[0055] For example, the top housing 210 and / or the bottom housing 215 may comprise one or more layers of copper, aluminum, stainless steel, or other metallic materials. For example, the top housing 210 and / or the bottom housing 215 may comprise one or more layers of copper, stainless steel, aluminum, polymer, ALD-coated polymer, flexible copper foil substrate (FCCL), polymer-coated copper, copper-clad polyimide film (Kapton), etc. For example, the thickness of the top housing 210 and / or the thickness of the bottom housing 215 may be less than approximately 0.01 mm, 0.024 mm, 0.036 mm, 0.050 mm, 0.075 mm, 0.1 mm, 0.2 mm, 1 mm, 2 mm, etc.

[0056] The top shell 210 is deformable to include a plurality of deformable portions 260 (or shell pillars or rough pillars) formed within the top shell 210. Because of the deformable portions 260 in the top shell 210, the top shell 210 can be considered a three-dimensional shell. The plurality of deformable portions 260 can provide structural integrity within the thermally grounded plane. For example, the plurality of deformable portions 260 can be multiple deformations formed in a planar shell. The plurality of deformable portions 260 can extend into the vapor structure 125 of the thermally grounded plane 200. For example, the plurality of deformable structures can be randomly formed on the top shell 210. For example, the plurality of deformable structures can be formed in an ordered array within the top shell 210. For example, the width 208 (or average width) between the deformable portions 260 can be less than 0.1 mm, 0.3 mm, 0.5 mm, 0.75 mm, 1 mm, 2 mm, 4 mm, etc. For example, the depth 209 (or average depth) of multiple deformed portions 260 may be less than approximately 500 micrometers, 200 micrometers, 100 micrometers, 50 micrometers, 25 micrometers, etc.

[0057] For example, the top housing 210 may be formed from a planar sheet to include a plurality of deformable portions 260. The plurality of deformable portions 260 may be a plurality of deformable portions extending outward relative to the plane of the planar sheet.

[0058] An inner surface of one of the plurality of deformable portions 260 may engage with a top surface 250 of the capillary structure 120. For example, the capillary structure 120 may engage with a bottom housing 215 to maintain structural integrity under the pressure difference between vapor pressure inside the thermal ground plane and ambient pressure outside the thermal ground plane. This may, for example, create an internal engagement and / or may provide support to allow for a high internal pressure. For example, one or more of the plurality of deformable portions 260 may engage with a plurality of corresponding portions of the capillary structure 120, which are also deformable in some way.

[0059] For example, one or more of the plurality of deformable portions 260 may be joined to the top of the capillary structure 120, or pressed into or formed in the capillary structure 120, for example, at a bond interface 250, to maintain structural integrity under the pressure difference between the vapor pressure inside the thermal grounding plane and the ambient pressure outside the thermal grounding plane. As another example, the capillary structure 120 may include a plurality of pillars, and one or more of the plurality of deformable portions 260 may be joined to the top of or into the capillary structure 120. For example, the capillary structure 120 may include a copper mesh.

[0060] As another example, the joining interface 250 may not be included. In this example, internal joining may not be required. For example, one or more of the plurality of deformable portions 260 may contact the capillary structure 120 without having a joining interface 250. As another example, one or more of the plurality of deformable portions 260 may not contact the capillary structure 120.

[0061] For example, capillary structure 120 may include a woven mesh, a non-woven mesh, a deformable mesh, mesh-on-pillars, multiple pillars, multiple micropillars, etc. For example, capillary structure 120 may include copper, aluminum, stainless steel, flexible copper foil substrate, polymer, combination of polymer and metal, organic materials, inorganic materials, etc.

[0062] For example, capillary structure 120 may engage with bottom housing 215 to maintain structural integrity under the pressure difference between vapor pressure inside the thermal grounding plane and ambient pressure outside the thermal grounding plane. For example, capillary structure 120 may engage with multiple portions of multiple deformable portions 260 at engagement interface 250 to maintain structural integrity under the pressure difference between vapor pressure inside the thermal grounding plane and ambient pressure outside the thermal grounding plane.

[0063] For example, Figure 2B This is a side view of a thermal grounding plane 200, which has a top capillary structure 265 disposed on the inner surface of the top housing 210. The top capillary structure 265 and the capillary structure 120 may be joined together at a joining interface 251. The joining interface 251 may be located on a portion of the top capillary structure 265, which corresponds to one or more of a plurality of deformable portions 260.

[0064] The top capillary structure 265 can engage with the inner surface of the top housing 210 before the formation of the multiple deformable portions 260.

[0065] For example, the top capillary structure 265 and / or capillary structure 120 can be formed into a multi-layer capillary structure by joining multiple layers of mesh.

[0066] In the case of meshes on deformable or cylindrical structures, the mesh can be flattened along its periphery to form a wall with a low capillary radius. Alternatively, the mesh can be bonded within a bondline that hermetically seals the thermally grounded plane. A mesh bonded within the bondline forms a solid wall. This wall prevents vapor from permeating into the porous capillary structure or the liquid channels beneath it. Vapor bubbles can block fluid flow in the liquid channels and reduce the maximum power allowed by a thermally grounded plane.

[0067] For example, capillary structure 120 may include multiple layers of mesh joined together. Some of the layers may have different mesh numbers, such that a finer mesh may be configured at the vapor / liquid interface to provide capillary forces, while a coarser mesh may be configured further away from the vapor / liquid interface to allow for highly permeable flow.

[0068] For example, the capillary structure 120 can be a deformable mesh with multiple meshpillars formed during a deformation process.

[0069] As another example, the top housing 210 may be coupled to a vapor support structure comprising a polymer on the top housing 210, which fills a deformable cavity outside the thermally grounded plane. This polymer may be fluorinated ethylene propylene (FEP) and provide high infrared emissivity.

[0070] For example, capillary structure 120 may engage with bottom housing 215 to maintain structural integrity under the pressure difference between vapor pressure inside the thermal grounding plane and ambient pressure outside the thermal grounding plane. For example, top capillary structure 265 may engage with top housing 210 to maintain structural integrity under the pressure difference between vapor pressure inside the thermal grounding plane and ambient pressure outside the thermal grounding plane. For example, capillary structure 120 may engage with multiple portions of top capillary structure 265 at engagement interface 251 to maintain structural integrity under the pressure difference between vapor pressure inside the thermal grounding plane and ambient pressure outside the thermal grounding plane.

[0071] Figure 3A This is a side view of a thermally grounded plane 300 having an internal joint 305 between a top housing 210 and a bottom housing 215. The thermally grounded plane 300 is similar to the thermally grounded plane 200. The internal joint 305 may be formed by an extended deformable portion 310. At the internal joint 305, the thickness of the thermally grounded plane at the internal joint is substantially the same as the thickness at the peripheral joint 140. For example, a diffusion bonding process using a flat tool can be used to further deform the top housing 210 to form the internal joint 305. For example, the capillary structure 120 may have an aperture to allow the extended deformable portion 310 to pass through the capillary structure 120 and engage with the bottom housing 215. For example, the top capillary structure 265 may have an aperture that allows the extended deformable portion 310 to pass through the top capillary structure 265 and engage with the bottom housing 215.

[0072] It may include multiple extended deformable portions 310.

[0073] The top housing 210 and the bottom housing 215 may be engaged with a capillary structure, and these capillary structures may have holes to allow the top housing 210 and the bottom housing 215 to contact and engage with each other. For example, the engagement of the top housing 210 and the bottom housing 215 may be made to maintain structural integrity under the pressure difference between the vapor pressure inside the thermal grounding plane and the ambient pressure outside the thermal grounding plane.

[0074] Figure 3B This is a side view of the thermally grounded plane 300. In this embodiment, the capillary structure 120 includes a capillary perimeter 370. The capillary perimeter 370 may surround the capillary structure 120 and / or any pores in the capillary structure 120. The capillary perimeter 370 may comprise the same material as the capillary structure 120, which is compressed to form smaller pores in the capillary perimeter 370. The smaller pores protect the liquid channels beneath the capillary structure from vapor permeation.

[0075] Figure 4A This is a side view of a thermally grounded plane 400 having a tiledwick 405 and a vapor support structure 410 disposed within a top housing 210 and a bottom housing 215. For example, the tiledwick 405 may comprise multiple layers of capillary tiles. The tiledwick 405 and the vapor support structure 410 may or may not be joined together.

[0076] Individual pavings in the paved capillary structure 405 may comprise two deformed mesh layers: one deformed into a substantially flat side, and the other deformed into a substantially columnar side. These two mesh layers may be bonded together along the column and along the periphery. This can create a highly permeable flow channel between the mesh layers while forcing a low capillary radius at any vapor-liquid interface. Another method to achieve both high permeability and a low capillary radius may include a fine mesh encapsulating a coarse mesh at the top and bottom.

[0077] For example, multiple paving stones in a capillary structure can be stacked in an overlapping pattern, such as... Figure 4B and Figure 4CAs shown. For example, the interface between two tiles may have low permeability and / or a low capillary radius. Liquids may flow over a wide area through the low-permeability region, which may allow the liquid to flow with low flow resistance. For example, a large single capillary structure, such as a mesh layer, can be placed under all the tiles, where the single mesh has a capillary radius similar to or smaller than that of the tiles. In this way, liquids can flow through the tiles or mesh while maintaining the surface tension associated with a small capillary radius.

[0078] For example, the vapor support structure 410 may include a foil bent to form a plurality of columns. The vapor support structure 410 may be separate from and distinctly different from the top housing 210 and / or the bottom housing 215. The vapor support structure 410 may include a flexible copper foil substrate, metal, copper mesh, and / or may be porous or solid. In some embodiments, the vapor support structure 410 may include a plurality of foils not bonded together. The foil may be corrugated in areas where there are no plurality of deformed vapor columns formed by a deformable mesh to increase the rigidity of the top housing 210 and / or the bottom housing 215. For example, the top housing 210 may be deformable to provide a plurality of deformed vapor columns with a corrugated structure.

[0079] For example, the capillary structure of each paving brick may include a deformable mesh having a substantially flat side facing the vapor-liquid interface and a substantially columnar side facing the liquid region. The periphery of the deformable mesh may be substantially flattened to create a wall region with a low capillary radius. Selected areas of the capillary structure are compressed to extend the height of the vapor chamber.

[0080] For example, selected areas of the capillary structure of a paved surface may be removed to create extended vaporflow cavities, which may be referred to as a deformed-open mesh (DO-Mesh). Multiple strings of vapor flow cut-outs in the mesh can be arranged in an alternating layout to allow parallel vapor flow paths. In some embodiments, the selected areas removed from the capillary structure may have partially filled peripheries to form a wall region with a low capillary radius. The wall region can be formed by flattening a mesh to include a flattened area around the mesh, or the wall region can be formed by a process of cutting open areas, such as by laser cutting to form the wall with a molten area.

[0081] Figure 5A This is a side view schematic diagram of a thermally grounded plane 500 with internal engagement. In this embodiment, the top housing 510 is substantially planar (e.g., undeformed). The top housing 510 and the bottom housing 215 may be sealed around the peripheries of the top housing 510 and the bottom housing 215, respectively. A vapor support structure 515 and a capillary structure 120 may be configured within the thermally grounded plane 500. In one embodiment, the vapor support structure 515 may engage with the top housing 510. In another embodiment, the vapor support structure 515 may engage with the capillary structure 120 engaged to the bottom housing 215. In yet another embodiment, the vapor support structure 515 may engage with both the top housing 510 and the capillary structure 120 simultaneously. The capillary structure 120 may engage with the bottom housing 215.

[0082] For example, vapor support structure 515 may include any features and / or properties of vapor support structure 410. For example, vapor support structure 515 may include the same or substantially the same material as capillary structure 120. For example, capillary structure 120 may include one or more layers of mesh having a first mesh number, and vapor support structure 515 may include multiple layers of mesh having a second mesh number lower than the first mesh number. In one specific embodiment, capillary structure 120 may have a mesh number of about #250, and vapor support structure 515 may have a mesh number of about #80. As another embodiment, capillary structure 120 may include multiple layers of mesh with different mesh numbers, and vapor support structure 515 may have a mesh number lower than the average mesh number of the multiple layers of mesh.

[0083] For example, a vapor support structure 515 may be engaged with the top housing 510 to maintain structural integrity under the pressure difference between the vapor pressure inside the thermal grounding plane and the ambient pressure outside the thermal grounding plane. For example, a capillary structure 120 may be engaged with the vapor support structure 515 to maintain structural integrity under the pressure difference between the vapor pressure inside the thermal grounding plane and the ambient pressure outside the thermal grounding plane. For example, a capillary structure 120 may be engaged with the bottom housing 215 to maintain structural integrity under the pressure difference between the vapor pressure inside the thermal grounding plane and the ambient pressure outside the thermal grounding plane.

[0084] Figure 5BThis is a side view of a thermally grounded plane 500 where capillary structure 120 is replaced by deformed capillary structure 520. The deformed capillary structure 520 can be one or more layers deformed to include multiple deformed meshes. For example, one or more of the deformations may extend in the vertical direction beyond substantially half the distance of the capillary structure (first deformation 522) and / or one or more of the deformations may extend in the vertical direction substantially through the entire capillary structure (second deformation 523). These deformations can be produced by flattening multiple portions of the deformed capillary structure 520.

[0085] For example, the deformed capillary structure 520 may be flattened at its periphery 535. The flattened periphery 535 may create multiple regions with smaller pore sizes, which establish multiple regions that restrict vapor inflow into the deformed capillary structure 520. The vapor support structure 515 may include a mesh with a low mesh count, lower than the mesh count of the deformed capillary structure 520.

[0086] As another embodiment, the deformable capillary 520 may be flattened and deformed around its entire or substantially entire volume. This may result in a smaller pore size for the entire deformable capillary 520. For example, a mesh may first be flattened around its entire body. This may result in a smaller pore size across the entire body of the mesh. The flattened mesh may then be deformed to produce various deformations (e.g., a first deformation 522 and / or a second deformation 523) in multiple portions of the mesh (e.g., at the periphery or other regions of the deformable capillary 520). For example, a mesh having a pore size of #200 may be flattened, which changes the pore size of the mesh to approximately #600.

[0087] Figure 6 This is a side view of a thermally grounded plane 500 with multiple sections of a vapor support structure 515 cut off or removed, leaving multiple openings 605 in a deformable open mesh (DO-mesh). The remaining area of ​​the vapor support structure 515 can provide mechanical support for the top housing 510. The openings 605 in the vapor support structure 515 can be aligned with the capillary structure 120, which can also be as follows: Figure 5B The diagram shows a deformable capillary structure 520. In some embodiments, the vapor support structure 515 may include cross-connectors of a mesh within the opening 605, which can provide mechanical flexibility to the opening 605. For example, the cross-connectors may be misaligned between the vapor support structure 515 and the capillary structure 120 or the deformable capillary structure 520 to prevent any bottlenecks in the vapor flow region.

[0088] Figure 7AThe diagram shows a top view of a foldable thermally grounded plane 700 in a static state. Figure 7B A foldable thermal grounding plane 700 in a stretched state is shown. The foldable thermal grounding plane 700 can be used, for example, in foldable mobile devices. When the mobile device is folded, the foldable thermal grounding plane 700 may stretch and extend. The foldable thermal grounding plane 700 allows for stretching and extending without damage.

[0089] The foldable thermal grounding plane 700 has a first rigid region 705, a second rigid region 706, and a foldable region 710. The foldable region 710 may be disposed between the first rigid region 705 and the second rigid region 706. The first rigid region 705 may have one or more attachment points 715, allowing the first rigid region 705 to be directly fixed to an electronic device. The second rigid region 706 may include one or more flexures 725 extending from the second rigid region 706 to an attachment point 720. The attachment point 720 and / or one or more attachment points 715 may be configured to be fixed to a heated area during use.

[0090] In use, when the foldable region 710 is bent, the second rigid region 706 may move relative to the electronic device without damaging the attachment point 720, because one or more flexures 725 stretch and recover during the folding action. The foldable region 710 and / or the second rigid region 706 may slide relative to the electronic device. The use of one or more flexures 725 allows all or more portions of the foldable thermally grounded plane 700 to move relative to each other in the horizontal direction, while movement in the vertical direction is very limited.

[0091] It may include a thermal connection for thermally connecting the foldable thermal ground plane 700 to an electronic device. The thermal connection may include an air gap, a low-friction thermal interface (e.g., polytetrafluoroethane or graphite) that allows the thermal ground plane to slide on a surface, or a stretchable elastomer material.

[0092] The foldable thermal grounding plane 700 may include waves in the top and bottom housings, which may not be bonded to capillary structures. The capillary structures may include cut-out areas to allow vapor to flow side-by-side with the liquid within the capillary structure. The capillary structure may be substantially flat between the waves of the housing. For example, the capillary structure may be substantially wavy, having the same wavelength as the waves in the housing. The top and bottom housing materials may be asymmetrical. The waves in the top and bottom housings may extend to and include the bonding area between the upper and lower housings. A wavy bond-line requires the top and bottom housings to be able to nest with each other. These waves may include sinusoidal, circular, elliptical, and rounded triangular waves. For example, the waves may not be nestable due to waveform asymmetry. This asymmetrical wave reduces strain associated with both wave formation and the bending of the wavy area. The foldable thermal grounding plane 700 may have waves transitioning from a wave design above the capillary structure to different wave designs in the bonding area. The thermal grounding plane 700 may also include a wave design above the capillary structure, which transitions to a flat area above the junction area. The shape of the transition may follow a smooth curve with two or more inflection points.

[0093] The capillary structure and vapor space of the foldable thermally grounded plane 700 can be formed in different ways. The capillary structure in the first rigid region 705 and the second rigid region 706 can be defined by a high capillary pressure capillary structure, while the capillary structure in the foldable region 710 can be defined by a multi-layered mesh, wherein the mesh layers are bonded to each other. For example, the high capillary pressure capillary structure can be formed by a mesh-on-pillars architecture. For example, the pillar can form a solid wall around the periphery of the high capillary pressure capillary structure, which can prevent vapor from entering the capillary structure below the mesh. For example, the wall can be porous, with pore sizes substantially smaller than the pore sizes of the capillary structure. For example, the mesh / pillar structure can be formed by a single deformable mesh, such as... Figure 5B As shown. The transition from a wavy mesh area to a flat mesh area may include a multi-layered mesh that substantially extends into the flat area. In this area, for example, the multi-layered mesh may be deformed to create vapor-support pillars. For example, in addition to the vapor chambers formed by the support structures, the multi-layered mesh may be cut to form multiple vapor flow channels.

[0094] For example, the foldable thermally grounded plane 700 may include a micro / nanoporous membrane in the foldable region 710. A layer of micro / nanoporous membrane may be bonded to a column array in the first rigid region 705, the second rigid region 706, and / or the foldable region 710. Such a layer of micro / nanoporous membrane can maintain high capillary pressure even when using fluids with low surface tension, including alcohols such as methanol, ethanol, and isopropanol; organic solvents such as acetone, pentane, and isohexane; and engineered fluids such as hydrofluoroethers, hydrofluoroketones, and other dielectric fluids. In these folded regions, vapor flow channels are formed by gaps in the capillary structure. A micro / nanoporous membrane layer with a solid wall may be formed between the column region and the vapor flow to prevent vapor from entering below the membrane. The bottom of the column array may be solid or porous, and if porous, it may be bonded to a second micro / nanoporous material. Materials used for micro / nanoporous membranes can be polymers, such as polyimide, polyester, polycarbonate, and polyetheretherketone (PEEK); metals, such as steel, stainless steel, aluminum, copper, and brass; or flexible ceramics, such as glass and alumina. Micro / nanoporous pores can be formed through methods such as mesh flattening, track-etching, dealloying, copolymer formation, photolithography and etching, electroforming, and anodizing.

[0095] Figures 8A to 13 The displayed thermal ground plane can be used in any application, such as high-power and high-heat-flux applications. High-power applications may include cooling processors (e.g., AI processors, graphics processors, etc.), high-power switches (e.g., metal-oxide-semiconductor field-effect transistors (MOSFETs), gallium nitride (GaN), etc.), etc.

[0096] Figure 8A This is a schematic diagram of one side view. Figure 8B This is a cut top view of a thermally grounded plane 800, which may be used, for example, in high-power and high-heat-flux applications. In this embodiment, the bottom housing 830 is substantially planar (e.g., undeformed) and flat. The top housing 825 and the bottom housing 830 may be sealed around the periphery of the top housing 825 and the periphery of the bottom housing 830.

[0097] For example, the top housing 825 may comprise a single-layer material with high thermal conductivity. For example, the top housing 825 may comprise copper, aluminum, stainless steel, silicon, ceramic, aluminum nitride (AlN), beryllium oxide (BeO), etc. For example, the top housing 825 may comprise a material with a thermal conductivity greater than about 200 W / m / k. As another embodiment, the top housing 825 may comprise a laminate composed of copper, a polymer, and copper. For such a laminated housing, thermal vias through the polymer layer can be used to reduce thermal resistance. For example, a cooling unit (e.g., a liquid cooling plate) can be connected to the inner copper layer through an opening in the polymer layer.

[0098] For example, the bottom housing 830 may comprise a single-layer material with high thermal conductivity. For example, the bottom housing 830 may comprise copper, aluminum, stainless steel, silicon, ceramic, aluminum nitride, beryllium oxide, etc. For example, the bottom housing 830 may comprise a material with a thermal conductivity greater than about 200 W / m / k. As another embodiment, the bottom housing 830 may comprise a laminate composed of copper, a polymer, and copper. For such a laminated housing, thermally conductive holes through the polymer layer can be used to reduce thermal resistance. For example, electronic devices can be connected to the inner copper layer through an opening in the polymer layer.

[0099] An evaporating / boiling capillary structure 805 and a condensing capillary structure 810 may be disposed within a thermally grounded plane 500. The evaporating / boiling capillary structure 805 may be coupled or engaged with an inner surface of the bottom housing 830, and / or the condensing capillary structure 810 may be coupled or engaged with an inner surface of the top housing 825. A plurality of support structures 815 may be disposed between the evaporating / boiling capillary structure 805 and the condensing capillary structure 810. For example, the plurality of support structures 815 may engage or contact the evaporating / boiling capillary structure 805 and the condensing capillary structure 810. The condensing capillary structure 810 and / or the plurality of support structures 815 may include any or all of the features or characteristics described herein with respect to capillary structure 120.

[0100] The condensing capillary structure 810 may include a mesh with pores small enough to prevent vapor from permeating into the condensing capillary structure 810.

[0101] Multiple liquid supply structures 820 may be configured in certain portions of the thermally grounded plane 800 (e.g., heating areas), located between the bottom housing 830 and the top housing 825. The multiple liquid supply structures 820 may be interwoven, mixed, or combined with multiple support structures 815. The multiple liquid supply structures 820 may include strips of a multilayer mesh. For example, the multiple liquid supply structures 820 may engage or contact with an evaporating / boiling capillary structure 805 and a condensing capillary structure 810. The multiple liquid supply structures 820 may provide vertical and horizontal liquid flow paths, allowing liquid to flow from the condensing capillary structure 810 to the evaporating / boiling capillary structure 805.

[0102] For example, the plurality of liquid supply structures 820 may comprise materials substantially similar to the evaporation / boiling capillary structure 805 and / or the condensation capillary structure 810. For example, compared to the evaporation / boiling capillary structure 805, the plurality of liquid supply structures 820 may be bent into an out-of-plane shape.

[0103] As another embodiment, the plurality of liquid supply structures 820 may include multilayer meshes joined together. The multilayer meshes may be substantially similar to each other. For example, three layers of mesh may be included, each having the same mesh count (e.g., #145). As another embodiment, the multilayer meshes may have different mesh counts: a first mesh with a mesh count of #400 may be joined to a mesh with a mesh count of #200, wherein the latter may be joined to another mesh with a mesh count of #400. For example, small pores in the mesh (e.g., mesh counts of #250, #300, or #400) may prevent vapor from permeating into the flow channels formed by the #200 mesh in the liquid supply structure 820.

[0104] For example, multiple portions of the vapor support structure 815 and multiple portions of the liquid supply structure 820 may be located in the same space or volume within the thermal ground plane.

[0105] For example, a condensing capillary structure 810 may engage with a top housing 825 to maintain structural integrity under the pressure difference between the vapor pressure inside the thermally grounded plane and the ambient pressure outside the thermally grounded plane. Similarly, an evaporating / boiling capillary structure 805 may engage with a bottom housing 830 to maintain structural integrity under the pressure difference between the vapor pressure inside the thermally grounded plane and the ambient pressure outside the thermally grounded plane. Furthermore, multiple support structures 815 may engage with the condensing capillary structure 810 and / or the evaporating / boiling capillary structure 805 to maintain structural integrity under the pressure difference between the vapor pressure inside the thermally grounded plane and the ambient pressure outside the thermally grounded plane.

[0106] Figure 9A and Figure 9BDifferent embodiments of multiple liquid supply structures 820 within a thermally grounded plane are shown. Figure 9A This illustrates a plurality of liquid supply structures 820 extending through the condensing capillary structure 810 to the top housing 825 and through the evaporating / boiling capillary structure 805 to the bottom housing 830. In this embodiment, the plurality of liquid supply structures 820 include non-planar bends in a triangular wave shape as shown. The triangular wave may be a trapezoidal wave in contact with the condensing capillary structure 810 and the evaporating / boiling capillary structure 805. Figure 9B The display may show multiple liquid supply structures 820 with an asymmetrical waveform, which, for example, allows for a larger contact area with the condensing capillary structure while limiting the contact area with the evaporating / boiling capillary structure.

[0107] Multiple liquid supply structures 820 may be a porous capillary structure or a multilayer mesh, allowing liquid from the condensing capillary structure 810 to flow in the heater region to the evaporating / boiling capillary structure 805. The capillary forces associated with the liquid supply structure 820 may be sufficient to prevent a capillary limit associated with the liquid in the boiling region. The liquid supply structure 820 may have fluid contact with both the condensing capillary structure 810 and the evaporating / boiling capillary structure 805 to allow liquid transport between them. The cross-sectional area of ​​the liquid supply structure 820 in contact with the evaporating / boiling capillary structure 805 is limited to prevent heating to the boiling point within the liquid supply structure 820. The liquid supply structure 820 effectively transports liquid vertically and horizontally. Horizontal transport helps cover a large heating area with high heat flux.

[0108] Multiple liquid supply structures 820 may be formed or cut to allow vapor to flow between the liquid supply structures. The multiple liquid supply structures 820 may be formed in a helical form, which may include cut-outs for vapor flow between the helical segments.

[0109] Figure 10A and Figure 10B Two embodiments of the condensation capillary structure 810 are shown. Figure 10A The condensation capillary structure 810 shown includes a mesh capillary structure on a column, comprising a mesh layer 806 on a plurality of columns 811. This capillary structure can be a deformed mesh having multiple mesh columns. The pore size of the mesh in the condensation capillary structure 810 can be less than 0.050 mm, for example, less than 0.010 mm, 0.025 mm, etc.

[0110] Figure 10BThe condensation capillary structure 810 shown illustrates a multilayer mesh with layers having different pore sizes. For example, the condensation capillary structure 810 may include a first mesh 812 and a second mesh 813 engaged with the top housing 825. The first mesh 812 may be engaged with the second mesh 813. The first mesh 812 may have a larger pore size than the second mesh 813. For example, the first mesh 812 may be a mesh with a pore size corresponding to #100, and the second mesh 813 may be a mesh with a pore size corresponding to #200. The finer mesh (smaller pore size) ensures effective condensation, while the second mesh 813 may have a coarser mesh (larger pore size), coupled to the top housing 825 to provide an effective fluid channel for condensate flow. For example, such a multilayer mesh can provide effective condensation and liquid flow.

[0111] Figure 11 This illustrates one embodiment of an evaporation / boiling capillary structure 805 (or a capillary structure 120 or a modified capillary structure 520). The evaporation / boiling capillary structure 805 may be joined to a bottom housing 830. The evaporation / boiling capillary structure 805 may include multiple mesh layers. In this embodiment, the evaporation / boiling capillary structure 805 includes a first mesh 221, a second mesh 222, and a third mesh 223. In one embodiment, the multiple mesh layers may have different pore sizes. For example, the first mesh 221 may have a pore size of #400, the second mesh 222 may have a pore size of #200, and the third mesh 223 may have a pore size of #100. For example, the mesh with the largest pore size may be joined to the bottom housing 830. For example, such a multilayered mesh can provide efficient evaporation and fluid flow. As another embodiment, each of the multiple mesh layers may have substantially similar pore sizes.

[0112] Figure 12 This is a side view of a thermally grounded plane 1200 with two types of vapor support structures, wherein hollow beads 1210 and / or solid cylinders 1205 are disposed between an evaporating / boiling capillary structure 805 and a condensing capillary structure 810. One or both can be used. For example, the solid cylinders 1205 and / or hollow beads 1210 can be engaged with the evaporating / boiling capillary structure 805 and / or the condensing capillary structure 810 to maintain structural integrity under the pressure difference between the vapor pressure inside the thermally grounded plane and the ambient pressure outside the thermally grounded plane.

[0113] Figure 13This is a side view of a thermal grounding plane 1200, which includes a deformable mesh 1310 as a vapor support / liquid supply structure disposed between a condensing capillary structure 810 and an evaporating / boiling capillary structure 805. In this embodiment, the vapor support structure and the liquid supply structure are the same structure using the deformable mesh 1310. For example, the deformable mesh 1310 may include a cut-out region near the heater. As another embodiment, the deformable mesh 1310 may extend across the heater region, and / or the liquid supply structure may be woven between the wires of the coarse mesh. For example, the deformable mesh 1310 may be coupled to the boiling capillary structures 805 and / or 810 to maintain structural integrity under the pressure difference between the vapor pressure inside the thermal grounding plane and the ambient pressure outside the thermal grounding plane. The deformable mesh 1310 may be a multilayer mesh.

[0114] For example, the vapor support structure and the liquid supply structure can be as follows: Figure 8A The design is integrated with the housing and / or deformable to accommodate different electronic device heights. For high heat flux applications, the electronic device must form effective thermal contact with a thermal interface material between the electronic device and the thermal ground plane. The required contact pressure level is very high. Corresponding to this high pressure level for each electronic device, one embodiment features a partially deformable housing / mesh. This partial deformation can accommodate different electronic device heights.

[0115] In some embodiments, the internal structure of the high heat flux ground plane includes micron or nanoscale textures. Such textures can be formed by methods such as metal oxidation, dealloying brass into porous copper, or ceramic deposition via atomic layer deposition.

[0116] Unless otherwise stated, the term "substantially" means within 5% or 10% of the value mentioned or within manufacturing tolerances. Unless otherwise stated, the term "about" means within 5% or 10% of the value mentioned or within manufacturing tolerances.

[0117] The conjunction "or" is inclusive.

[0118] The terms “first,” “second,” “third,” etc., are used to distinguish individual elements and are not used to indicate a specific order of these elements unless otherwise stated, explicitly described, or required.

[0119] To provide a thorough understanding of the claimed subject matter, numerous specific details have been listed. However, those skilled in the art will understand that the claimed subject matter can be implemented without these specific details. In other instances, a method, apparatus, or system known to those skilled in the art has not been described in detail so as not to obscure the claimed subject matter.

[0120] Although the subject matter of this case has been described in detail with specific embodiments, those skilled in the art can easily modify and change these examples to equivalents after understanding the foregoing. Therefore, the content disclosed herein is presented for illustrative purposes and not for limitation, and such modifications, changes, and / or additions to the subject matter are not excluded, as these are obvious to those skilled in the art.

Claims

1. A thermal ground plane, comprising: a first housing that is substantially planar; a second housing, wherein an outer periphery of the first housing and an outer periphery of the second housing are joined to one another to form a hermetic seal, wherein the second housing is deformed to form a vapor support structure comprising a plurality of deformations; a working fluid configured within the first housing and the second housing; a permeable wick configured on an inner surface of the first housing for liquid transport between the first housing and the second housing.

2. The thermal ground plane of claim 1, wherein the second housing comprises at least one of copper, aluminum, and stainless steel.

3. The thermal ground plane of claim 1, wherein the second housing comprises a flexible laminate having a plurality of layers, wherein at least one of the plurality of layers comprises a polymer.

4. The thermal ground plane of claim 1, wherein the second housing has a thickness less than 0.036 mm.

5. The thermal ground plane of claim 1, wherein the permeable wick is joined to portions of the first housing and the second housing.

6. The thermal ground plane of claim 1, further comprising a second wick configured on an inner surface of the second housing.

7. The thermal ground plane of claim 6, wherein portions of the second wick are joined to the second housing and portions of the second wick are joined to the permeable wick, and wherein the permeable wick is joined to the first housing.

8. The thermal ground plane of claim 1, wherein the permeable wick is flattened and deformed to form deformations for liquid transport.

9. The thermal ground plane of claim 1, wherein the thermal ground plane comprises flexures configured to connect to a substrate and allow relative movement of portions of the thermal ground plane.

10. A thermal ground plane, comprising: a first housing; a first wick joined to the first housing, the first wick for liquid transport associated with evaporation or boiling; a second housing, wherein an outer periphery of the first housing and an outer periphery of the second housing are joined to one another to form a hermetic seal; a second wick joined to the second housing, the second wick for liquid transport associated with condensation; a liquid supply structure in contact with the first wick and the second wick for liquid transport, the liquid supply structure having a structure configured to allow vertical liquid transport between the first wick and the second wick and horizontal liquid transport along the liquid supply structure; and a working fluid configured within the first housing and the second housing.

11. The thermal ground plane of claim 10, wherein the liquid supply structure comprises a mesh selected from the group consisting of copper mesh, stainless steel mesh, and polymer mesh.

12. The thermal ground plane of claim 10, wherein the liquid supply structure comprises a plurality of mesh layers.

13. The thermal ground plane of claim 12, wherein at least one of the plurality of mesh layers comprises a mesh number of #300 or greater.

14. The thermal ground plane of claim 10, wherein the liquid supply structure has a shape selected from the group consisting of a wave shape, a triangular shape, a trapezoidal shape, and an asymmetric wave shape.

15. The thermal ground plane of claim 10, further comprising a vapor support structure disposed between the first housing and the second housing.

16. The thermal ground plane of claim 15, wherein the vapor support structure and the liquid supply structure are disposed in the same space within the thermal ground plane.

17. The thermal ground plane of claim 10, wherein the second capillary structure comprises a plurality of mesh layers.

18. The thermal ground plane of claim 17, wherein the plurality of mesh layers comprises at least a first mesh layer and a second mesh layer, the first mesh layer having a pore size greater than a pore size of the second mesh layer, and the first mesh layer is disposed between the second housing and the second mesh layer.

19. The thermal ground plane of claim 10, wherein the first capillary structure comprises a plurality of mesh layers.

20. The thermal ground plane of claim 19, wherein the plurality of mesh layers comprises at least a first mesh layer and a second mesh layer, the first mesh layer having a pore size greater than a pore size of the second mesh layer, and the second mesh layer is disposed between the first housing and the first mesh layer.

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