Evaporator assemblies, vapor chambers, and methods for fabricating vapor chambers

Abstract

To provide evaporator assemblies, vapor chamber assemblies, and methods for fabricating a vapor chamber.SOLUTION: In one embodiment, an evaporator assembly for a vapor chamber includes an evaporator surface, an array of posts extending from the evaporator surface, and an array of vapor vents within the evaporator surface. Each vapor vent in the array of vapor vents is configured as a depression within the evaporator surface. The evaporator assembly further includes a porous layer disposed on the evaporator surface, the array of posts, and the array of vapor vents.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] This application relates, in general terms, to a vapor chamber, and more particularly to a vapor chamber having low thermal resistance and high heat dissipation. [Background technology]

[0002] Heat-generating devices such as motors, power electronics equipment, and microprocessors generate a significant amount of heat that must be removed to allow them to operate below their maximum operating temperature. Removing heat flux from heat-generating devices becomes a challenge as power demands increase and the size of heat-generating components decreases.

[0003] Therefore, alternative cooling devices are needed to remove the heat flux from the heat-generating equipment. [Overview of the project]

[0004] In one embodiment, the evaporator assembly for a vapor chamber includes an evaporator surface, an array of posts extending from the evaporator surface, and an array of vapor vents within the evaporator surface. Each vapor vent in the array of vapor vents is configured as a recess within the evaporator surface. The evaporator assembly further includes a porous layer disposed on the evaporator surface, the array of posts, and the array of vapor vents.

[0005] In another embodiment, the assembly includes an evaporator assembly and a condenser plate. The evaporator assembly includes an evaporator surface, an array of posts extending from the evaporator surface, and an array of vapor vents within the evaporator surface. Each vapor vent in the array of vapor vents is configured as a recess within the evaporator surface. The evaporator assembly further includes a porous layer disposed on the evaporator surface, the array of posts, and the array of vapor vents. The condenser plate includes a condensing surface, which is joined to the upper surface of the array of posts such that the evaporator assembly and the condenser plate define a vapor chamber.

[0006] In yet another embodiment, a method for manufacturing a vapor chamber includes forming an array of posts and an array of vents on the evaporator surface; coating the evaporator surface, the array of posts and the array of vents with a metal powder containing metal particles; sintering the metal powder to form a porous layer; and joining the condensing surface of a condenser plate to the upper surface of the array of posts.

[0007] These and additional features presented by the embodiments described herein can be better understood by reading the following detailed description together with the accompanying drawings. [Brief explanation of the drawing]

[0008] The embodiments shown in the drawings are by their nature illustrative and exemplary, and are not intended to limit the scope of the claims. The following detailed description of the exemplary embodiments will be best understood when read in conjunction with the accompanying drawings. In the drawings, similar structures are indicated by the same reference numerals.

[0009] [Figure 1A] This is a schematic top perspective view of an example of an evaporator assembly having an evaporator surface with an array of posts and an array of vents, according to one or more embodiments described and illustrated herein. [Figure 1B] Figure 1A is a schematic top perspective view of a post example of the evaporator assembly. [Figure 2] This is a schematic bottom perspective view of an example of a condenser plate having a condensing surface according to one or more embodiments described and illustrated herein. [Figure 3] This is a schematic cross-sectional view of a vapor chamber according to one or more embodiments described and illustrated herein. [Figure 4] This is a schematic diagram of an example of an evaporator surface having an array of posts and an array of steam vents, according to one or more embodiments described and illustrated herein, in which the distance between adjacent posts and the distance between adjacent steam vents varies across the evaporator surface. [Figure 5]This is a schematic diagram of an example of an evaporator surface having an array of posts and an array of vapor vents, according to one or more embodiments described and illustrated herein, in which the size of the individual posts and the size of the individual vapor vents vary across the evaporator surface. [Figure 6] This figure schematically shows plots of total thermal resistance with respect to power variation for four different vapor chamber designs according to one or more embodiments described and illustrated herein. [Figure 7] This figure schematically shows plots of heater temperature with power variation for four different vapor chamber designs in Figure 6, according to one or more embodiments described and illustrated herein. [Figure 8] This figure schematically shows plots of through-plane thermal resistance with respect to power variation for four different vapor chamber designs in Figure 6, according to one or more embodiments described and illustrated herein. [Figure 9] This figure is a flowchart illustrating an example of a method for manufacturing a vapor chamber according to one or more embodiments described and illustrated herein. [Modes for carrying out the invention]

[0010] As can be seen from the attached drawings, embodiments of the present disclosure relate to a cooling device configured as a vapor chamber for removing heat flux from heat-generating equipment such as electronic devices. Electronic devices such as microprocessors and power electronics switch equipment ("power electronics equipment") generate a large amount of heat, which must be removed in order to keep the electronic device below its maximum operating temperature. Electronic devices operating above their maximum operating temperature are at risk of failure. Cooling devices can be used to remove heat flux to keep electronic devices (or other heat-generating equipment such as motors) below their maximum operating temperature.

[0011] In electrified vehicles, wide-bandgap (WBG) equipment such as silicon carbide can replace conventional silicon-based power semiconductors because it has lower power loss and higher efficiency. Furthermore, WBG equipment offers higher heat flux (e.g., 1 kW / cm²). 2 They dissipate even higher temperatures and operate at temperatures above 473K. The high operating temperatures of WBG equipment provide a larger thermal budget for designing lower-cost and more compact cooling systems, such as air cooling. To obtain a compact, high-performance air cooling system, heat transfer from the heat source to the heatsink plays a crucial role.

[0012] A vapor chamber is a cooling device that removes heat flux by causing a cooling fluid to undergo a phase change from liquid to gas. Typically, a vapor chamber is a closed system in which a liquid coolant fluid exists on an evaporator surface that receives a heat flux from a heat-generating device. When this coolant is heated to its boiling point, it evaporates into a gas and moves toward the condenser surface. The condenser surface is cooler than the evaporator surface to lower the temperature of the gas, causing it to condense back into a liquid and return to the evaporator surface. In some cases, a wicking structure can be provided to move the coolant toward the evaporator surface by capillary action. Conventionally, vapor chamber heat diffusers are used to efficiently diffuse heat, but their performance is approximately 500 W / cm² over a 1cm x 1cm area. 2 The heat flux is limited to less than a certain amount.

[0013] A major problem associated with vapor chambers is the phenomenon of dry-out. Dry-out occurs when the power of the heat-generating equipment raises the temperature to a level where the coolant cannot return to the evaporator surface quickly enough to cool the equipment. In fact, the evaporator surface "dries out" because there is no coolant at all. This causes the temperature of the heat-generating equipment to rise above its maximum operating temperature.

[0014] Embodiments of the present disclosure provide a more efficient vapor chamber that significantly increases the draw-out temperature of the vapor chamber and thus significantly increases the maximum operating power of the heat generating device. In embodiments of the present disclosure, an array of porous posts connects the evaporator surface to the condenser surface to provide a wicking path for returning condensed coolant from the condenser surface to the evaporator surface. Further, an array of vapor vents is disposed within the evaporator surface to enable additional nucleation sites and more efficient evaporation of the cooling water. The combination of the array of posts and the array of vapor vents enables the heat generating device to operate at high temperatures with minimal risk of dry-out, such as operating at a power greater than 600 W (not limited thereto). Further, the vapor chamber of the embodiments described herein provides low thermal resistance. In particular, the vapor chamber being tested in the embodiments described herein dissipates a maximum heat flux of 589 W / cm 2 and provides a minimum total thermal resistance of 0.28 K / W.

[0015] Various embodiments of a method of manufacturing an evaporator assembly, a power electronics assembly, and a vapor chamber are described in detail below.

[0016] Referring to FIG. 1A, an example of an evaporator assembly 110 that can be used with a condenser plate to form a vapor chamber is schematically shown. The evaporator assembly 110 is configured as an evaporator plate having an evaporator surface 111 and a heat receiving surface 117. The evaporator assembly 110 is manufactured from a thermally conductive material such as copper (but not limited thereto). The heat receiving surface 117 receives a heat receiving device (not shown) such as a power electronics device. The power electronics device can be a power switching device such as a metal oxide semiconductor field effect power transistor (MOSFET), a power transistor, a power insulated gate bipolar transistor (IGBT), and the like. The power electronics device can be a wide bandgap (WBG) device including (but not limited to) silicon carbide. It should be understood that the embodiments are not limited to electronic devices or heat generating devices.

[0017] Evaporator assembly 110 includes a peripheral surface 116 that surrounds the evaporator surface 116. As will be described in more detail below, the peripheral surface 116 can be coupled to the peripheral surface of the condenser plate to form a vapor chamber. The evaporator assembly 110 further includes an inlet port 118 for providing a cooling fluid to the vapor chamber. The inlet port 118 can include a valve to close the vapor chamber during operation, thereby providing a closed system.

[0018] The evaporator surface 111 is offset from the peripheral surface 116 in the negative coordinate system vertical direction (i.e., the negative z-axis direction) so that the evaporator assembly 110 can form a vapor chamber when coupled to the condenser plate. In this embodiment, the evaporator assembly 110 further includes a porous peripheral ledge 115 configured to receive the porous condenser surface of the condenser plate. In other embodiments, it should be understood that no peripheral ledge is provided. Instead, the entire peripheral wall is porous without a ledge.

[0019] Evaporator assembly 110 includes an array of posts 112 extending from the evaporator surface 111. As will be described in more detail below, the array of posts 112 provides a wicking path for condensed coolant to return to the evaporator surface 111. The array of posts 112 is defined by a plurality of columns and a plurality of rows. The individual posts 112 of adjacent columns are offset from each other by an offset distance d1 in the x-axis direction. The individual posts 112 of adjacent rows are offset from each other by an offset distance d2 in the y-axis direction. The distances d1 and d2 are determined according to the overall dimensions of the cooling device without being limited by the present disclosure.

[0020] Post 112 is shown as cylindrical; however, the embodiments are not limited thereto. For example, post 112 can be configured as a prism or other cross-sectional shape. The embodiments are not further limited by the size of the post. As a non-limiting example, in the cylindrical embodiment, the diameter of post 112 can be 0.5 mm to 3 mm, 1 mm to 1.5 mm, or 1 mm. It should be seen that the diameter can be other values ​​depending on the overall size of the cooling device. Furthermore, the height of the array of posts 112 is not limited by this disclosure. Non-limiting heights include 0.5 mm to 5 mm, 1 mm to 4 mm, 1.5 mm to 3 mm, or 2.5 mm. It should be seen that other heights are available.

[0021] The evaporator surface 111 further includes an array of vapor vents 114, which are recesses in the negative z-axis direction within the evaporator surface 111. As will be described in more detail below, the array of vapor vents 114 increases the efficiency of the vapor chamber and allows for high heat flux dissipation without dryout. The dimensions and shape of the vapor vents 114 are not limited by this disclosure. In the embodiments illustrated, the individual vapor vents 114 are circular. However, embodiments are not limited to vapor vents 114 having a circular shape, and other shapes such as rectangular, oval, triangular, or any shape are possible. As a non-limiting example, the diameter of an individual vapor vent 114 may be 0.25 mm to 2 mm, 0.5 mm to 1.5 mm, or 1 mm. Other diameters may be available depending on the overall size of the cooling system. Non-limiting depths of an individual vapor vent 114 include 0.1 mm to 1 mm, 0.25 mm to 0.75 mm, or 0.5 mm. It should be seen that other depths may be available.

[0022] Individual steam vents 114 in adjacent columns are offset from each other by an offset distance d3 in the x-axis direction. Individual steam vents 114 in adjacent rows are offset from each other by an offset distance d4 in the y-axis direction. The values ​​of distances d3 and d4 are not limited by this disclosure and are determined according to the overall dimensions of the cooling system. The array of posts 112 and the array of steam vents 114 intersect with each other. Thus, the array of posts 112 and the array of steam vents 114 define a structural array, where each column of the structural array comprises alternating individual posts and individual steam vents, and each row of the structural array comprises alternating individual posts and individual steam vents. Each individual steam vent 114 is surrounded by four individual posts 112.

[0023] The distillation assembly 110 further includes a porous layer 119 positioned on the evaporator surface 111, the array of posts 112, and the array of vapor vents 114. The porous layer 119 has multiple pores that act as a wicking structure to return the liquid cooling fluid to the evaporator layer 111. The thickness of the porous layer 119 defines the dimensions of the array of posts 112 and the array of vapor vents 114 described above.

[0024] Figure 1B is an enlarged view of a post. Each post 112 in an array of posts 112 can be configured as a pin 113 (e.g., a pin fin) coated with a porous layer 119. Thus, a post 112 is formed by a core which is a solid pin 113 and an outer porous layer. The pins can be formed by any known or future-developed process, including (but not limited to) machining or chemical etching. For example, an array of posts 112 may include an array of smaller diameter pin fins, with the porous layer 119 surrounding the array of pins 113 defining the overall diameter of the array of posts 112. In a non-limiting example, each pin 113 may have a diameter of 0.5 mm, the porous layer 119 may have a thickness of 0.5 mm, and each post 112 may have a diameter of 1 mm. The thickness of the porous layer 119 is not limited by this disclosure. As a non-limiting example, the thickness of the porous layer 119 can be 0.2 mm to 1 mm, 0.25 mm to 1 mm, or 0.5 mm. It should be clear that other thicknesses can be used.

[0025] In some embodiments, the porous layer 119 can be manufactured by coating it with a powder containing metal particles, such as copper particles. The size of the metal particles determines the size of the pores inside the porous layer 119. As a non-limiting example, the metal particles can have a diameter of 60 to 120 μm. After application of the metal particle powder, the metal particles are sintered to form the porous layer 119 by raising the temperature of the evaporator assembly 110 above the sintering temperature of the metal particles (for example, 750°C to 1000°C for copper particles).

[0026] Figure 2 shows a condenser plate 120 having a condenser surface 122 and a cooling surface 125. The condenser surface 122 can be surrounded by a condenser peripheral surface 124 configured to be coupled to or in contact with the peripheral surface 116 of the evaporator 110. The condenser surface 122 can be formed by a porous layer extending from the condenser peripheral surface 124. The condenser surface 122 can also be formed by sintering metal particles (e.g., copper particles) as described above. The condenser surface 122 has a width, height, and depth that fit within the peripheral surface 116 of the evaporator assembly 110.

[0027] When forming the vapor chamber, the condenser surface 122 is positioned above the array of posts 112 and the porous surrounding ledge 115 (if installed). After placing the condenser plate 120 on the evaporator assembly 110, the two components are joined by means of diffusion bonding or the like. The joining of these two components defines a vapor chamber that can then be filled with cooling fluid.

[0028] Figure 3 is a cross-sectional view of an example assembly 100, which includes a cooling device 101 with a vapor chamber 128, a heat generating device 130, and a heat sink 140. Figure 3 is a simplified diagram for illustrative purposes. In particular, the row shown includes only two posts 112 and three vapor vents 114. It should be noted that the row of the cooling device 101 disclosed herein may include many additional posts 112 and vapor vents 114.

[0029] As shown in Figure 3, the post 112 comprises pin fins 113 surrounded by a porous layer 119. As described above, the pin fins 113 can be formed by machining or chemical etching the evaporator surface 111. Having a post 112 with a solid pin fin core 113 reduces the thermal resistance between the condenser plate 120 and the evaporator assembly 110 compared to a post made solely from a porous layer, further improving the performance of the vapor chamber.

[0030] After the vapor chamber 128 is sealed by joining the condenser plate 120 to the evaporator assembly 110, the cooling fluid is introduced into the vapor chamber 128 through the inlet port (Figure 1A) 118. During operation, heat-generating equipment 130, such as power electronics equipment, emits a heat flux. The coolant on the evaporator surface 111 and within the porous layer 119 receives the heat flux and its temperature rises above its boiling point. The coolant begins to boil and changes phase from liquid to vapor. The pores within the porous layer 119 provide nucleation sites for efficient boiling. The cooling vapor rises toward the condenser surface 122, as indicated by arrow A.

[0031] The heat sink 140 is attached to the cooling surface 125 of the condenser plate 120. The heat sink 140 can be any cooling device, such as a finned heat sink, a heat diffuser, a liquid cooler, or something similar. The heat sink 140 condenses the heat flux from the condenser plate 120 to cool the cooling vapor so that the cooling fluid condenses back into a liquid. The porous condenser surface 122 and porous post 112 draw back the condensed cooling liquid toward the evaporator surface 111, as indicated by arrow B, where it is heated again and turns into vapor.

[0032] The vapor vent 114 reduces the resistance to vapor leakage from the evaporator surface 111. The vapor vent 114 provides a more favorable location for nucleated bubbles to leak from the porous layer 119 of the evaporator surface 111. Thus, the vapor vent 114 allows vapor to pass toward the condenser surface 122.

[0033] The size, shape, and / or density of the posts 112 and / or vapor vents 114 may vary across the evaporator surface 111 to address localized hotspots. For example, the size, shape, and / or density of the posts 112 and / or vapor vents 114 directly above the heat-generating equipment 130 may differ from that of the posts 112 and / or vapor vents 114 further away from the heat-generating equipment 130. The size, shape, and / or density of the posts 112 and / or vapor vents 114 can vary arbitrarily across the evaporator surface 111.

[0034] Figure 4 is a partial view of an example of an evaporator surface 211, where adjacent posts 212 located in the center have a spacing dp1, and adjacent vapor vents 214 located in the center have a spacing dv1. However, adjacent posts 212 closer to the periphery of the evaporator surface 211 have a spacing dp2, and adjacent vapor vents 214 closer to the periphery of the evaporator surface 211 have a spacing dv2. In the illustrated example, dp1 is greater than dp2, and dv1 is greater than dv2. For example, the density of posts 212 and vapor vents 214 can be in the area outside the heat-generating equipment or just above the heat-generating equipment.

[0035] Figure 5 is a partial view of an example of an evaporator surface 311 where the sizes of the posts 312 and the steam vents 314 vary. The adjacent posts 312 in the center have a diameter of dia p1 and the adjacent steam vents 314 in the center have a diameter of dia v1 . However, the adjacent posts 312 closer to the periphery of the evaporator surface 311 further have a diameter of dia p2 and the adjacent steam vents 314 closer to the periphery of the evaporator surface further have a diameter of dia v2 . In the illustrated example, dia p1 is larger than dia p2 , and dia v1 is larger than dia v2 . In other embodiments, dia p1 is smaller than dia p2 and dia v1 is smaller than dia v2 .

[0036] To evaluate the performance of the vapor chamber, two sets of experiments were conducted. One experiment measured the total thermal resistance of the vapor chamber in an air-cooling test, and the second experiment extracted the surface direct thermal resistance of the vapor chamber itself. As shown in Figure 1A, a vapor chamber was manufactured with machined posts having a diameter of about 1.5 mm and a height of 2.4 mm with a porous layer and steam vents having a diameter of 1 mm and a depth of 0.5 mm. Three comparative vapor chamber examples were also manufactured. The first comparative vapor chamber includes the above single-layer evaporator surface without posts or steam vents. The second comparative vapor chamber includes posts (non-solid pin fins) having a diameter of 1.5 mm and a height of 2.4 mm made only of the porous layer material and does not include steam vents. The third comparative vapor chamber includes posts made of pin fins having a diameter of 0.5 mm and a height of 2.4 mm that are surrounded by a porous layer to form posts having a diameter of 1 mm and a height of 2.4 mm. The third comparative vapor chamber does not include steam vents.

[0037] Figures 6 and 7 show the changes in thermal resistance and heater temperature with respect to input power, respectively. Trace 401 is the first comparative example, trace 402 is the second comparative example, trace 403 is the third comparative example, and trace 404 is a vapor chamber with a post and vapor vent. As shown in Figure 6, the trends in thermal resistance of each vapor chamber are very similar. That is, the thermal resistance is high at low power (<100W), decreases when the onset of nucleation boiling (ONB) is reached, and remains almost constant in the nucleation boiling region. When the input power is below 100W, the first comparative example (i.e., single-layer vapor chamber) has lower thermal resistance than the second comparative example (i.e., vapor chamber with sintered post) and the third comparative example (i.e., vapor chamber with machined post). However, in the boiling region with an input power >300W, the thermal resistance of the first comparative example is higher than that of the post-equipped design.

[0038] The thermal resistance of a vapor chamber with machined posts (trace 403) is slightly lower than that of a vapor chamber with sintered posts (trace 402) throughout the entire power range. For example, at an input power of 110W, the thermal resistance of a vapor chamber with machined posts (trace 403) is approximately 6% lower than that of a vapor chamber with sintered posts (trace 402), and at a high input power of 450W, it is 11% lower.

[0039] Of all vapor chamber designs, the vapor chamber with a machined post and vent according to this disclosure (trace 404) has the lowest thermal resistance across the entire range of input power. Unlike the tendencies of other vapor chambers, the thermal resistance of the machined post and vent vapor chamber (trace 404) does not form a stable level in the boiling region, but continues to decrease until the maximum power supply capacity is reached.

[0040] Furthermore, the single-layer vapor chamber (trace 401) reached dryout (DO) at an input power of 467W. Dryout was observed as a linear rise in transient heater temperature without reaching a steady state. The remaining vapor chamber designs did not exhibit this dryout phenomenon. The maximum power dissipated by the sintered post (trace 402) and machined post designs (trace 403) was 450W and 447W, respectively. The test was stopped because the heater temperature exceeded the maximum allowable temperature of 478°C. In the case of the machined post + vent vapor chamber (404), the test was stopped because the input power supply reached its maximum capacity.

[0041] Figure 7 shows the change in heater temperature with respect to input power. The vapor chambers of the sintered post (trace 502) and machined post (trace 503) show a linear increase in temperature with power until the ONB power reaches approximately 100W. Unlike the vapor chambers of the sintered and machined posts, the ONB points of the single-layer (trace 501) and machined post + vent (trace 504) vapor chambers are not clearly observed in Figure 7. Furthermore, the rate of increase in heater temperature of the machined post + vent vapor chamber begins to decrease at 300W-400W (as can be seen in trace 504), and thereafter the heater temperature increases linearly. The machined post + vent vapor chamber can dissipate considerably more power than other designs at the same heater temperature. For example, at a heater temperature of 473°C, the machined post + vent vapor chamber dissipates 30% more power than the single-layer vapor chamber (trace 501).

[0042] Figure 8 shows the change in the perpendicular thermal resistance of the vapor chamber as a function of input power. The single-layer vapor chamber (trace 601) generally has higher thermal resistance compared to the post-type design. The vapor chambers with sintered posts (trace 602) and machined posts (trace 603) have slightly higher thermal resistance than the single-layer design in the low power range of <50W. ONB is observed in the vapor chambers with sintered posts (trace 602) and machined posts (trace 603), respectively, at input powers of approximately 98W and 93W. At ONB power, the perpendicular thermal resistance of both vapor chambers drops dramatically, almost halving.

[0043] The machined post-vent vapor chamber (Trace 604) has the lowest surface thermal resistance across the entire power range. For example, at input powers of 110W and 559W, the surface thermal resistance of the machined post-vent vapor chamber is 0.18K / W and 0.27KW, respectively. At powers higher than ONB power, the thermal resistance of all vapor chambers increases linearly with input power. Of all the vapor chambers tested, only the single-layer vapor chamber (Trace 601) reached dry-out (DO) at an input power of 457W. The maximum power dissipated by the remaining vapor chamber designs was limited by the power supply's maximum current capacity (~10A), so the test was terminated. The maximum power dissipated by the machined post-vent vapor chamber (Trace 604) was 589W.

[0044] Figure 9 is a flowchart 700 illustrating an example of a method for manufacturing a vapor chamber. In block 702, the array of posts and the array of vents are formed on the evaporator surface of the evaporator plate. The array of posts and the array of vents can be manufactured, for example, by machining. Alternatively, the array of posts and the array of vents can be manufactured by chemical etching. For example, if the evaporator surface is made of copper, a mask can be placed over the evaporator surface and a chemical etching agent such as ferric chloride can be applied to form the desired array of posts and the array of vents.

[0045] In block 704, a metal powder containing metal particles is applied to the evaporator surface, the post array, and the vent array. The metal particles may include, for example, copper particles. In block 706, the metal powder is sintered to form a porous layer around the evaporator surface, the post array, and the vent array. The porous layer provides both enhanced nucleation sites and a wicking structure for returning the coolant to the evaporator surface and the vent array.

[0046] In block 708, the porous condenser surface of the condenser plate is positioned on the upper surface of the post array. This defines a vapor chamber between the condenser surface and the evaporator surface. Finally, in block 710, the condenser surface is joined to the upper surface of the post array. As a non-limiting example, the condenser surface is joined to the upper surface of the post array by diffusion bonding.

[0047] Embodiments of this disclosure should be seen as relating to a vapor chamber having an evaporator surface with an array of posts and an array of vapor vents. Each post comprises a solid core surrounded by a porous layer. The solid core may be provided by pin fins to reduce the thermal resistance between the condenser surface and the evaporator surface. The array of vents provides pathways to facilitate vapor leakage and additional nucleation sites for vapor. The vapor chambers described herein have low thermal resistance and high dry-out temperatures. Vapor chambers can be used to cool power electronics equipment such as broadband gap power electronics equipment that generates a large amount of heat flux used in inverter circuits of electric or hybrid electric vehicles.

[0048] While specific embodiments have been illustrated and described herein, it should be evident that a variety of other changes and modifications can be made without departing from the spirit and scope of the claims. Furthermore, while various forms of the claims have been described herein, these forms are not necessarily used in combination. Therefore, the claims are intended to encompass all changes and modifications that fall within the scope of the claims.

Claims

1. 1. An evaporator assembly for a vapor chamber, comprising: an evaporator surface opposite the heat receiving surface; an array of posts extending from the evaporator surface; an array of steam vents in the evaporator face, each steam vent in the array of steam vents configured as a recess in the evaporator face; a porous layer disposed on the evaporator surface, the array of posts, and the array of vapor vents; An evaporator assembly comprising:

2. The evaporator assembly of claim 1 , wherein the array of posts is interwoven with the array of vapor vents.

3. a spacing between adjacent posts of the array of posts varies across the evaporator surface; the spacing between adjacent vapor vents in the array of vapor vents varies across the evaporator face; The evaporator assembly of claim 1 .

4. 2. The evaporator assembly of claim 1, wherein at least one of a size and a shape of individual vapor vents in the array of vapor vents varies across the evaporator face.

5. The evaporator assembly of claim 1, wherein the porous layer has a thickness of 0.20 mm to 1 mm, including the end points.

6. 10. The evaporator assembly of claim 1, wherein the depth of individual vapor vents varies across the evaporator face.

7. 2. The evaporator assembly of claim 1, wherein the array of posts and the array of vapor vents define a structural array, each row of the structural array comprising alternating individual posts and individual vents.

8. 1. An assembly comprising an evaporator assembly and a condenser plate, The evaporator assembly includes: an evaporator surface opposite the heat receiving surface; an array of posts extending from the evaporator surface; an array of steam vents in the evaporator face, each steam vent in the array of steam vents configured as a recess in the evaporator face; a porous layer disposed on the evaporator surface, the array of posts, and the array of vapor vents; Equipped with the condenser plate includes a condenser surface, the condenser surface being bonded to an upper surface of the array of posts such that the evaporator assembly and the condenser plate define a vapor chamber.

9. The assembly further comprising an electronic device coupled to the heat receiving surface.

9. The assembly of claim 8.

10. the condenser surface is provided on a condenser plate further comprising a cooling surface; The assembly further comprises a heat sink coupled to the cooling surface.

10. The assembly of claim 9.

11. The assembly of claim 8 , wherein the array of posts is interwoven within the array of vapor vents.

12. a spacing between adjacent posts of the array of posts varies across the evaporator surface; the spacing between adjacent vapor vents in the array of vapor vents varies across the evaporator surface; 9. The assembly of claim 8.

13. The assembly of claim 8 , wherein at least one of a size and a shape of individual vapor vents in the array of vapor vents varies across the evaporator face.

14. The assembly of claim 8, wherein the porous layer has a thickness of 0.20 mm to 1 mm including the endpoints.

15. The assembly of claim 8 , wherein a depth of individual steam vents varies across said evaporator face.

16. 9. The assembly of claim 8, wherein said array of posts and said array of vapor vents define a structural array, each row of said structural array comprising alternating individual posts and individual vents.

17. The array of posts extends from the evaporator face along a positive z-axis; the array of vapor vents extends in a negative z-axis direction into the evaporator face; The evaporator assembly of claim 1 .

18. The array of posts extends from the evaporator face in a positive z-axis direction; the array of vapor vents extends in a negative z-axis direction into the evaporator face; 9. The assembly of claim 8.

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