KR20220075762A - The Vapor Chamber - Google Patents

Abstract

This application relates to a vapor chamber. The vapor chamber of the present application may have various performances within a given size, for example, improved heat load capacity and effective thermal conductivity.

Description

The Vapor Chamber

This application relates to a vapor chamber.

As the performance of electronic products improved, the calorific value of the products also increased. As the amount of heat generated by an electronic product increases, a means for effectively dissipating heat from the product, for example, a means such as a heat-radiating element, has been required.

A vapor chamber is known as a representative example of a heat dissipation element. As mentioned in Non-Patent Document 1, the vapor chamber is usually composed of a sealed case having a rectangular parallelepiped shape, a porous wick formed along the rim of the internal space of the case, and a working fluid filling the internal space of the case. When the vapor chamber is placed on an external heat source, the working fluid is evaporated by the heat of the external heat source. Since evaporation is an endothermic reaction, the temperature decreases as the working fluid evaporates. The evaporated working fluid moves along the interior space of the vapor chamber and is condensed in the process. Since condensation is an exothermic reaction, heat is released from the opposite side of the heat source during the condensation process. As a result, if the vapor chamber is used, the heat generated from the heat source can be discharged to the outside. In addition, the working liquid generated during the condensation of the working fluid moves along the wick to an area where evaporation occurs (see FIG. 1 ). At this time, the working fluid moves by the capillary force of the working fluid acting on the wick. In addition, since the heat transfer direction of the vapor chamber is in the planar direction, the vapor chamber has an advantage that can be applied to a heat source of a large area.

The performance of a vapor chamber is usually determined by the properties of the wick formed therein. As mentioned in Patent Document 1 and Non-Patent Document 2, the wick exists in the form of a pattern having a certain shape and shape in the vapor chamber. However, since the vapor chamber usually has a certain size, there is a limit to improving the heat dissipation characteristics within the predetermined size as described above.

Japanese Patent Publication No. 6587164

Entropy, 2020, 22(1), 35 Applied Thermal Engineering Vol. 167 (2020), 114726

It is an object of the present application to provide a vapor chamber. An object of the present application is to provide a vapor chamber capable of having various performances, for example, improved heat load capacity and effective thermal conductivity, etc. within a given vapor chamber size.

The purpose of the present application is not limited to the above purpose.

Among the physical properties mentioned in this specification, when the measured temperature affects the result, unless otherwise specified, the corresponding physical property is a physical property measured at room temperature. The term ambient temperature is the natural temperature, whether heated or not reduced, usually a temperature in the range of about 10°C to 30°C, or a temperature on the order of about 23°C or about 25°C. In addition, unless otherwise specified in this specification, the unit of temperature is °C.

Among the physical properties mentioned in this specification, when the measured pressure affects the result, unless otherwise specified, the corresponding physical property is a physical property measured at normal pressure. The term atmospheric pressure refers to a natural temperature that has not been pressurized or depressurized, and usually about 1 atmosphere is referred to as atmospheric pressure.

An exemplary vapor chamber of the present invention is described in detail below with reference to the drawings.

In the following description, the drawings may be exaggerated for easy understanding, but this may be understood by focusing on the interrelationship between the components.

The present application relates to a heat dissipation device capable of effectively controlling heat generated during the operation of a battery or various electronic devices. More specifically, the present application relates to a vapor chamber as a heat dissipation element. While conventionally known heat-pipes transfer heat in one direction (1-direction), the vapor chamber has the advantage of transferring heat in two directions (2-direction).

2 is an exemplary schematic diagram of a vapor chamber according to the present application. Referring to FIG. 2 , the vapor chamber according to the present application includes a first substrate 100 ; a second substrate 200 facing the first substrate; It is positioned between the first substrate and the second substrate and includes a closed space 300 in which the working fluid is sealed.

The above first and second expressions do not prescribe a front-to-back or up-and-down relationship of the substrate.

As an example, the first substrate or the second substrate may be a metal substrate. More preferably, each of the first substrate and the second substrate may be a metal substrate.

A thermally conductive substrate may be used as the metal substrate. In one example, the thermal conductivity of the first substrate and the second substrate is about 8 W/mK or more, about 10 W/mK or more, about 15 W/mK or more, about 20 W/mK or more, about 25 W/mK or more, respectively. or more, about 30 W/mK or more, about 35 W/mK or more, about 40 W/mK or more, about 45 W/mK or more, about 50 W/mK or more, about 55 W/mK or more, about 60 W/mK or more , about 65 W/mK or more, about 70 W/mK or more, about 75 W/mK or more, about 80 W/mK or more, about 85 W/mK or more, or about 90 W/mK or more. The metal substrate may obtain a vapor chamber having excellent heat dissipation efficiency as the thermal conductivity is higher, and thus the upper limit thereof is not particularly limited, and may be, for example, about 1,000 W/mK or less.

The specific type of the metal substrate is not particularly limited as long as it has the above-mentioned thermal conductivity, and for example, SUS (Stainless Steel), copper, gold, silver, aluminum, silver, nickel, iron, cobalt, magnesium, molybdenum. , may be any one selected from the group consisting of tungsten, platinum, magnesium and zinc, or a substrate of an alloy of two or more of the above, but is not limited thereto.

As an example, the type of the working fluid enclosed in the sealed space may be determined according to an operating temperature range in which the vapor chamber should operate. Various types of working fluids are known, from compounds having a very low boiling point (eg, a temperature in the range of 2K to 4K) to a very high temperature (eg, a temperature in the range of 2,000K to 3,000K) Various kinds of components can be applied up to compounds having a boiling point of An exemplary working fluid is water, and it is known that vapor chambers applying water as the working fluid are operable at temperatures usually within the range of 20°C to 150°C.

A plurality of vapor passage portions through which the vapor of the working fluid evaporated by an external heat source passes and a liquid passage portion through which a liquid working fluid passes are formed in the sealed space, and the closed space is an evaporation in which the working fluid is evaporated by an external heat source includes area.

In the above, the external heat source means heat transferred from the outside to the vapor chamber, and for example, may mean heat generated during the operation of a battery or various electronic devices.

In the above description, the evaporation region may mean a region in which a working fluid is evaporated to generate steam, which may mean a region in a vapor chamber adjacent to an external heat source. The external heat source may be located on the vapor chamber in consideration of the structure of the vapor chamber and heat dissipation efficiency of the vapor chamber, for example, the external heat source may be located on the central portion of the vapor chamber. The central portion of the vapor chamber refers to a direction perpendicular to the long axis direction at 1/2 of the long axis direction (eg, the x direction in FIG. 2 ) and the short axis direction of the vapor chamber (eg, FIG. 2 ). in the y-direction) may mean a portion located at a point where the direction perpendicular to the short-axis direction intersects at 1/2 of the position. Hereinafter, it is assumed that the evaporation region is positioned on the central portion of the vapor chamber, but the evaporation region is not limited to the central portion of the vapor chamber.

3 is a schematic diagram showing a closed space 300 of a conventional vapor chamber. In the closed space 300 of the conventional vapor chamber, a plurality of liquid passage units 310 are positioned in the long axis direction (x-direction) of the vapor chamber, and a vapor passage portion 320 is positioned between the plurality of liquid passage portions, and the vapor It has a structure in which the evaporation region 330 is located at the center of the chamber. In addition, the width of the plurality of liquid passage portions and the width of the vapor passage portion are constant. As described above, since the conventional vapor chamber has a certain standard, there is a limit to improving heat dissipation characteristics within a predetermined size. For example, when the temperature of the external heat source is high, a dry-out phenomenon easily occurs in the evaporation region of the vapor chamber in which the external heat source is located, thereby reducing the heat dissipation efficiency by the vapor chamber.

The present invention can effectively suppress the dry-out phenomenon in the evaporation region even when the temperature of the external heat source is high, so that an improved heat dissipation effect, for example, improved heat load capacity and effective thermal conductivity conductivity). Hereinafter, exemplary embodiments of the present application will be described in detail.

4 is a schematic diagram showing a closed space of the vapor chamber according to the first embodiment of the present application. In the sealed space 300 of the vapor chamber according to the first embodiment of the present application, a plurality of vapor passage portions 320 through which the vapor of the working fluid evaporated by an external heat source passes, and a liquid passage portion through which the liquid working fluid passes. 310 is formed, the sealed space includes an evaporation region 330 in which the working fluid is evaporated by an external heat source, and at least two vapor flow passages 320 are formed in the liquid passage portion ( 310).

In the above, the meaning that the at least two vapor flow passages are partitioned by the liquid passage in the evaporation region may mean that the at least two vapor flow passages exist in separate spaces in the evaporation region.

A vapor chamber including a closed area having a structure in which at least two vapor flow passage portions are partitioned by a liquid passage portion in the evaporation area can effectively suppress the dry-out phenomenon in the evaporation area, and thus a wider operating temperature It can have an effective heat dissipation effect even in the range.

As an example, the liquid passage part 310 may include a central wick 311 disposed along a direction crossing the evaporation region 330 ; and at least one or more peripheral wicks 312 extending from the central wick along a direction away from the evaporation region.

The term wick refers to a liquid passage portion having a capillary structure that acts as a passage through which a working fluid moves.

In the above, the direction transverse to the evaporation region means the short axis direction (eg, the y direction) of the vapor chamber.

As an example, at least one peripheral wick 312 extending from a central wick along a direction away from the evaporation region extends in a first direction, wherein the at least one peripheral wick is opposite to the first direction may extend in a second direction of the direction. The first direction refers to an x direction in FIG. 4 , and a direction opposite to the first direction refers to a direction opposite to the x direction (-x direction) in FIG. 4 .

As an example, the plurality of vapor flow passages and one or more peripheral wicks may be alternately disposed. The alternate arrangement means, for example, a structure in which a vapor flow passage part and a peripheral wick are alternately disposed such as a vapor flow passage part, a peripheral wick, and a vapor flow passage part in the y direction of the vapor chamber, or a peripheral wick and a vapor flow passage part and a structure in which the peripheral wick and the vapor flow passage part are alternately arranged like the peripheral wick.

As an example, the at least two peripheral wicks may have a symmetrical structure or an asymmetrical structure with respect to the central wick. For example, referring to FIG. 4 , the peripheral wick in the first direction and the peripheral wick in the second direction with respect to the central wick 330 may have a symmetrical structure.

The vapor of the working fluid evaporated in the evaporation region by the external heat source moves in a direction away from the central wick in both directions (or in the direction of the condensation region) with respect to the central wick, is cooled and condensed to become a liquid working fluid. The liquid working fluid enters the surrounding wick and moves to the evaporation zone by capillary force. According to the first embodiment, the at least one peripheral wick extends from the central wick, so that the liquid working fluid that has passed through the one or more peripheral wicks to the vaporization region can travel to the central wick. On the other hand, even if there is a difference in evaporation rate according to temperature in the evaporation region, the central wick is connected to one or more peripheral wicks, so that the liquid working fluid can be quickly supplied to a place in the evaporation area with a high evaporation rate. Therefore, it is possible to effectively suppress the occurrence of dry-out in the evaporation region. Therefore, the vapor chamber can operate smoothly even in a higher temperature range.

5 to 7 are schematic views showing the closed space of the vapor chamber according to the second to fourth embodiments of the present application. 5 to 7 are the same as the closed space of the vapor chamber according to the first embodiment, except that the fluid connection structures of the central wick and the peripheral wick are different. Accordingly, in the following description, the connection structure between the central wick and the peripheral wick among the structures of FIGS. 5 to 7 will be mainly described.

Referring to FIG. 5 , the liquid flow passages 311 and 312 of the vapor chamber according to the second embodiment of the present application have a plurality of center wicks 311a and 311b disposed apart from each other in a direction crossing the evaporation region 330 . , 311c); and one or more peripheral wicks (312) extending from each central wick along a direction away from the evaporation region, wherein the at least two central wicks are fluidly movably connected therethrough.

In the above description, the meaning that the at least two central wicks are fluidly movably connected through the peripheral wick means that, for example, the liquid working fluid moving to any one central wick 311a moves to the peripheral wick connected to the central wick. This means that the working fluid moving to the peripheral wick may move to the other central wick 311b.

Also according to the second embodiment, since the plurality of central wicks are disposed apart from each other in a direction crossing the evaporation region, and the two central wicks are fluidly movably connected through the peripheral wick, the working fluid flows into the evaporation region. can move smoothly. Therefore, it is possible to quickly supply the liquid working fluid to a place where the evaporation rate is relatively fast in the evaporation region. Therefore, it is possible to effectively suppress the occurrence of dry-out in the evaporation region. Therefore, the vapor chamber can operate smoothly even in a higher temperature range.

Referring to FIG. 6 , the liquid flow passages 311 and 312 of the vapor chamber according to the third embodiment of the present application have bent portions 313a bent along the direction in which the central wick 311 crosses the evaporation region 330 , 313b), and the at least one main wall wick 312 may extend from the bent portions 313a and 313b of the central wick 311 . In the bent portion, the peripheral wick and the central wick may be fluidly connected at a predetermined angle. For example, the peripheral wick and the central wick may be fluidly connected at an angle range of greater than about 0 to less than 90 degrees. As another example, the peripheral wick and the central wick may be at least about 5 degrees, 10 degrees, 15 degrees, 20 degrees or more, or about 25 degrees or more, and about 85 degrees or less, 80 degrees or less, 75 degrees or less, or about 70 degrees. The following angular ranges may be fluidly connected.

Also according to the third embodiment, the liquid working fluid can smoothly move through the evaporation region through the central wick including the bent portion bent along the direction transverse to the evaporation region and the peripheral wick connected from the bent portion of the central wick. Therefore, it is possible to quickly supply a liquid working fluid to a place where the evaporation rate is fast. Therefore, it is possible to effectively suppress the occurrence of dry-out in the evaporation region, and the vapor chamber can operate smoothly even in a higher temperature range.

Referring to FIG. 7 , liquid flow passages 311 and 312 of the vapor chamber of the vapor chamber according to the fourth embodiment of the present application include a central wick 311 disposed in a direction crossing the evaporation region; and at least one or more peripheral wicks 320 extending from the central wick in a direction away from the evaporation region, wherein the at least one or more peripheral wicks extend in a first direction, and the at least one peripheral wick extends in the first direction. may extend in a second direction opposite to each other, and the peripheral wick extending in the first direction and the peripheral wick extending in the second direction may extend at different points 314a and 314b of the central wick, respectively.

According to the fourth embodiment, the peripheral wick in the first direction and the peripheral wick in the second direction have an asymmetric structure with respect to the central wick. The peripheral wick extending in the first direction and the peripheral wick extending in the second direction are each connected at different points of the central wick, and therefore, a liquid working fluid moving to the central wick through the peripheral wick extending in the first direction. and the liquid working fluid moving to the central wick through the peripheral wick extending in the second direction is respectively moved to different points of the central wick. Therefore, the moving efficiency can be increased compared to the case where the liquid working fluid is moved to the same central wick. Specifically, when the working fluid displaced from the first direction and the working fluid displaced from the second direction move to the same point of the central wick, the working fluid may be oversupplied at that point, and thus a further inflow into the point The moving speed of the working fluid may be reduced. However, when the working fluid moved from the first direction and the working fluid moved from the second direction move to different points of the central wick, it is possible to prevent oversupply of the working fluid. Therefore, the working fluid can move smoothly along the central wick, so that dry-out in the evaporation region can be more effectively suppressed, and the vapor chamber can be operated smoothly even in a higher temperature range.

As an example, the liquid passage portion may occupy a range of 5% to 90% of the volume of 100% of the closed space. In another example, the liquid passage portion occupies about 10% or more, 15% or more, 20% or more, or about 25% or more of the volume of 100% of the volume of the sealed space, or about 85% or less, 80% or less, 75% or less, or about 70% or less can occupy a volume range of When the volume occupied by the liquid passage portion in the enclosed space is less than 5% or exceeds 90%, the liquid working fluid and the vapor phase working fluid may be disadvantageous in forming a smooth flow in the enclosed space. Specifically, when the volume occupied by the liquid flow passage part is less than 5%, it is not sufficient to move the liquid working fluid to the evaporation region through the liquid flow passage part. When the volume occupied by the liquid flow passage part exceeds 90%, the vapor phase working fluid It may not be enough to move in a direction away from the evaporation region (condensation region direction) through the vapor flow passage.

As an example, the liquid passage part may be a porous metal layer including thermally conductive metal particles. When the liquid passage part is a porous metal layer including thermally conductive metal particles, heat dissipation efficiency may be improved.

Meanwhile, the term porous metal layer refers to a porous structure including a metal as a main component. In the above, having a metal as a main component means that the proportion of metal is 55 wt% or more, 60 wt% or more, 65 wt% or more, 70 wt% or more, 75 wt% or more, 80 wt% or more, 85 wt% based on the total weight of the metal layer. It means a case of weight % or more, 90 weight % or more, or 95 weight % or more. The upper limit of the ratio of the metal included as the main component is not particularly limited, and may be, for example, 100% by weight.

In addition, the term porosity may mean a case in which the porosity is at least 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 75% or more, or 80% or more. The upper limit of the porosity is not particularly limited, and for example, may be less than about 100%, less than about 99%, less than about 98%, less than about 95%, or less than about 90%. In the above, the porosity may be calculated in a known manner by calculating the density of the metal layer.

The thermally conductive metal particles have, in one example, a thermal conductivity of about 8 W/mK or more, about 10 W/mK or more, about 15 W/mK or more, about 20 W/mK or more, about 25 W/mK or more, about 30 W/mK or more, about 35 W/mK or more, about 40 W/mK or more, about 45 W/mK or more, about 50 W/mK or more, about 55 W/mK or more, about 60 W/mK or more, about 65 W/mK or greater, about 70 W/mK or greater, about 75 W/mK or greater, about 80 W/mK or greater, about 85 W/mK or greater, or about 90 W/mK or greater. The metal particles may obtain a liquid channel portion having excellent heat dissipation efficiency as the thermal conductivity is higher, and thus the upper limit thereof is not particularly limited, and may be, for example, about 1,000 W/mK or less.

Specific types of the metal particles are not particularly limited as long as they have the above-mentioned thermal conductivity, and for example, copper, gold, silver, aluminum, silver, nickel, iron, cobalt, magnesium, molybdenum, tungsten, platinum, magnesium. And it may be any one selected from the group consisting of zinc or an alloy of two or more of the above, but is not limited thereto.

The shape of the metal particles may be appropriately selected in consideration of the desired pore size, porosity, or pore shape of the liquid passage part. For example, the metal particles may have various shapes such as a substantially spherical shape, a needle shape, a plate shape, a dendrite shape, or a star shape.

In one example, the average particle diameter of the metal particles may be in the range of about 100 nm to 200 μm. Within the above range, the average particle diameter may be appropriately selected in consideration of the porosity, pore size, or pore shape of the desired porous metal layer.

The thermally conductive metal particles included in the liquid passage part may have an average particle diameter in the range of 100 nm to 200 μm. Within the above range, the average particle diameter may be appropriately selected in consideration of the pore size or porosity of the liquid channel portion.

As an example, the liquid passage part may include at least a metal having an appropriate relative permeability and conductivity. The application of such a metal may allow sintering according to the method to be smoothly performed when the induction heating method is applied when forming the liquid flow passage in a method of manufacturing a vapor chamber to be described later.

For example, as the metal, a metal having a relative magnetic permeability of 90 or more may be used. In the above, the relative permeability (μr) is the ratio (μ/μ0) of the magnetic permeability (μ) of the material to the magnetic permeability (μ0) in a vacuum. The metal used in the present application has a relative permeability of 95 or more, 100 or more, 110 or more, 120 or more, 130 or more, 140 or more, 150 or more, 160 or more, 170 or more, 180 or more, 190 or more, 200 or more, 210 or more, 220 or more, 230 or more, 240 or more, 250 or more, 260 or more, 270 or more, 280 or more, 290 or more, 300 or more, 310 or more, 320 or more, 330 or more, 340 or more, 350 or more, 360 or more, 370 or more, 380 or more , 390 or more, 400 or more, 410 or more, 420 or more, 430 or more, 440 or more, 450 or more, 460 or more, 470 or more, 480 or more, 490 or more, 500 or more, 510 or more, 520 or more, 530 or more, 540 or more, 550 or more or more, 560 or more, 570 or more, 580 or more, or 590 or more. The upper limit of the relative permeability is not particularly limited because the higher the value, the higher the heat is generated when an electromagnetic field for induction heating is applied in a method of manufacturing a vapor chamber to be described later. In one example, the upper limit of the relative permeability may be, for example, about 300,000 or less.

The metal has a conductivity at 20°C of about 8 MS/m or more, 9 MS/m or more, 10 MS/m or more, 11 MS/m or more, 12 MS/m or more, 13 MS/m or more, or 14.5 MS/m or more. It may be a metal or an alloy thereof. The upper limit of the conductivity is not particularly limited, and may be, for example, about 30 MS/m or less, 25 MS/m or less, or 20 MS/m or less.

In the present application, the metal having the above relative permeability and conductivity may be simply referred to as a conductive magnetic metal.

By applying the conductive magnetic metal, sintering can be performed more effectively when an induction heating process is performed in a method of manufacturing a vapor chamber to be described later. Such a metal may be exemplified by nickel, iron or cobalt, but is not limited thereto.

As an example, the liquid channel portion may have an average pore size of 100 μm or less. The pore size may be confirmed by, for example, scanning electron microscope (SEM) image analysis. The lower limit of the pore size is not particularly limited, and may be, for example, about 1 nm to 1 μm.

As an example, the liquid channel portion may have a porosity of 30% or more. In the above, the porosity may be calculated in a known manner by calculating the density of the liquid channel portion. In another example, the porosity is about 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, or about 65% or more, or about 99% or less, 95% or less, 90% or less , 85% or less, 80% or less, or about 75% or less.

As an example, the filling rate (R) of the working fluid enclosed in the sealed space may satisfy the following general formula (1).

[General formula 1]

30 ≤ R (%) = (Lv / Wv) * 100 ≤ 200

In Formula 1, R is the filling rate of the working fluid enclosed in the sealed space, Lv is the volume of the working fluid enclosed in the sealed space, and Wv is the volume of pores in the liquid passage part existing in the sealed space.

In Formula 1, the filling rate (R) of the working fluid may be, for example, about 35% or more, 40% or more, 45% or more, 50% or more, or about 40% or more, and about 190% or less, 180% or less, 170% or less or about 160% or less.

If the filling rate (R ) of the working fluid enclosed in the enclosed space does not reach 30%, the dry-out phenomenon in the evaporation area may intensify, and if it exceeds 200%, the working fluid may leak from the vapor chamber. have.

When the liquid flow passage part has the above characteristics, the liquid working fluid can be more easily moved to the evaporation area, and thus the dry-out phenomenon in the evaporation area can be more effectively suppressed. In addition, the liquid channel portion has excellent thermal conductivity, so that heat dissipation efficiency can be improved.

The excellent heat dissipation characteristics of the vapor chamber of the present application are more significant when an external heat source is disposed together. For example, when an external heat source is positioned in the vaporization region of the vapor chamber with respect to the vapor chamber of the present application and the conventional vapor chamber, the vapor chamber of the present application has relatively excellent heat dissipation characteristics (this point is more detailed).

The present application also relates to a method for manufacturing a vapor chamber. The components used in the method of manufacturing the vapor chamber may be the same as those described above.

The method of manufacturing a vapor chamber according to the present application may include pattern-coating a slurry including thermally conductive metal particles on a support, and sintering the pattern-coated slurry to form a liquid passage on the support.

As shown in FIGS. 4, 5, 6 or 7, the pattern coating on the support may be pattern-coated on the support using a slurry so as to have the same pattern as the pattern of the liquid flow passage formed in the closed space.

If necessary, drying the pattern-coated slurry under suitable conditions may be performed between the pattern coating on the support and the sintering process. When the drying process proceeds, the conditions are not particularly limited, and, for example, may be performed at a temperature within the range of about 20° C. to about 150° C. for about 20 minutes to 5 hours, but is not limited thereto.

A method of performing sintering of the pattern-coated slurry on the support is not particularly limited, and a known sintering method that applies appropriate heat in consideration of the material composition or shape of the pattern-coated slurry may be applied. The sintering temperature and sintering time applied at this time are not particularly limited, and may be set in consideration of the material composition or shape of the slurry.

As an example, the sintering may be performed by an induction heating method. That is, as described above, when the slurry includes a conductive magnetic metal, an induction heating method may be applied. While including pores uniformly formed by this method, the mechanical properties are excellent, and the porosity of the metal layer is adjusted to a desired level can be more smoothly manufactured.

The induction heating is a phenomenon in which heat is generated in a specific metal when an electromagnetic field is applied. For example, when an electromagnetic field is applied to a conductive magnetic metal having appropriate conductivity and permeability, eddy currents are generated in the metal, and Joule heating is generated due to the resistance of the metal. Through this phenomenon, the sintering process of the pattern-coated slurry on the support may be performed. When this method is applied, sintering of the liquid channel portion coated with the pattern on the support can be carried out in a short time to ensure fairness, and at the same time, it is a thin film form with high porosity, has a small pore size, and has excellent adhesion to the support. A metal layer can be prepared.

Accordingly, the sintering process may include applying heat or an electromagnetic field to the pattern-coated slurry. In the above, the application of heat may be performed by treating the pattern-coated slurry at a temperature within the range of about 300° C. to 2,000° C. for a time within the range of 30 minutes to 10 hours using an appropriate means such as an oven.

In addition, Joule heating may be generated in the conductive magnetic metal due to an induction heating phenomenon even by application of an electromagnetic field, and thereby the structure may be sintered. In this case, the conditions for applying the electromagnetic field are not particularly limited as they are determined according to the type and ratio of the conductive magnetic metal in the slurry. For example, the induction heating may be performed using an induction heater formed in the form of a coil or the like. In addition, induction heating, for example, may be performed by applying a current of about 100A to 1,000A. In another example, the magnitude of the applied current may be 900 A or less, 800 A or less, 700 A or less, 600 A or less, 500 A or less, or 400 A or less. The magnitude of the current may be about 150 A or more, about 200 A or more, or about 250 A or more in another example.

Induction heating, for example, may be performed at a frequency of about 100 kHz to 1,000 kHz. In another example, the frequency may be 900 kHz or less, 800 kHz or less, 700 kHz or less, 600 kHz or less, 500 kHz or less, or 450 kHz or less. The frequency may be about 150 kHz or more, about 200 kHz or more, or about 250 kHz or more in another example.

The application of the electromagnetic field for the induction heating may be performed within a range of, for example, about 1 minute to 10 hours. In another example, the application time may be about 10 minutes or more, about 20 minutes or more, or about 30 minutes or more. The application time is, in another example, about 9 hours or less, about 8 hours or less, about 7 hours or less, about 6 hours or less, about 5 hours or less, about 4 hours or less, about 3 hours or less, about 2 hours or less, about 2 hours or less, about It may be 1 hour or less or about 30 minutes or less.

The above-mentioned induction heating conditions, for example, an applied current, a frequency, and an application time may be changed in consideration of the type and ratio of the conductive magnetic metal as described above.

The sintering of the liquid channel portion pattern-coated on the support is performed by either means of the application of the heat or the electromagnetic field, or both are applied simultaneously, that is, by applying appropriate heat together with the application of the electromagnetic field. can also be done

As an example, the support may be a metal substrate, a glass substrate, or a polymer substrate.

In one embodiment, when the support is a metal substrate, the method for manufacturing the vapor chamber includes sintering a pattern-coated slurry on a metal substrate (hereinafter, may be referred to as a 'first metal substrate') on the first metal substrate. The method may further include forming a liquid passage portion and bonding the edges of the first metal substrate and the second metal substrate in a state in which the second metal substrate is disposed to face the liquid passage portion of the first metal substrate. Meanwhile, in the above, the second metal substrate may be a planar metal substrate or a metal substrate having the same pattern formed when facing the liquid passage portion of the first metal substrate.

In another embodiment, when the support is a glass substrate or a polymer substrate, the vapor chamber manufacturing method is to sinter the pattern-coated slip on the glass substrate or the polymer substrate to form a liquid passage portion on the glass substrate or the polymer substrate, and the glass substrate or the polymer substrate. Separating the pattern-formed liquid channel portion from the substrate or the polymer substrate, and then bonding the edges of the first and second metal substrates with the separated liquid channel portion positioned between the first and second metal substrates. may further include.

In the above, a method of bonding the first metal substrate and the second metal substrate is not particularly limited, and a known metal attachment method may be applied. An enclosed space is formed between the first metal substrate and the second metal substrate by bonding the first metal substrate and the second metal substrate.

Meanwhile, a method of encapsulating the working fluid in the sealed space is not particularly limited, and a known encapsulation method may be used. For example, at least one of the first and second substrates is provided with an injection hole through which a working fluid is injected, so that after bonding the edges of the first and second metal substrates, at least one of the first and second substrates After injecting the working fluid through the inlet provided in the , the working fluid can be sealed in the sealed space by vacuum sealing the inlet using a well-known sealing agent such as an epoxy resin.

The vapor chamber of the present application may have various performances within a given size, for example, improved heat load capacity and effective thermal conductivity.

1 is a simplified view of a driving principle of a vapor chamber.
2 is an exemplary schematic diagram of a vapor chamber according to the present application.
3 is a plan view of a closed space in a conventional vapor chamber.
4 to 7 are plan views of an exemplary closed space in the vapor chamber according to the present application.
8 is a simplified view of the manufacturing process of the vapor chamber of the present application.

Hereinafter, the present application will be described in detail through examples. However, the protection scope of the present application is not limited by the examples described below.

Qmax measurement

Qmax means maximum heat transport power (unit: W), and is measured in the following manner. That is, the higher this value, the better the heat dissipation performance.

(1) In the vapor chambers manufactured in Examples and Comparative Examples, a heat source (direct current power supply) is connected to the evaporation region, and a cooling bath (Cooling bath) is connected to the condensation region.

(2) Connect the thermocouple to 7 points which are arranged at intervals of 12mm along the long axis direction (x direction) of the steam chamber.

(3) Apply heat at 0.5 W from the heat source, and when thermal equilibrium occurs and the temperature change at each point is less than 0.1°C, the temperature of each of the seven points is measured.

(4) At this time, when the temperature difference between the point closest to the heat source and the point farthest from the heat source at the seven points becomes 6°C, Qmax is obtained by subtracting 0.4W, which is an error depending on the measurement environment, from the power applied from the heat source.

On the other hand, Qmax evaluation was described as a ratio of the Qmax values of the remaining preparation examples based on the Qmax value when the position of the external heat source in Comparative Example 1 was in the evaporation region.

Measurement of Max temperature

The maximum temperature means a temperature at which the vapor chambers manufactured in the following Examples and Comparative Examples can operate smoothly, and is measured in the following manner. On the other hand, the higher the maximum temperature, the better the performance of suppressing the dry-out phenomenon in the evaporation region.

(1) As in the Qmax measurement method, connect a heat source (DC power supply) to the vapor chamber evaporation area, and connect a cooling bath to the condensation area.

(2) Connect the thermocouple to 7 points which are arranged at intervals of 12mm along the long axis direction (x direction) of the steam chamber.

(3) Apply heat at 0.2 W from the heat source, and set the temperature of the cooling equipment to be 6℃ different from the temperature of the heat source.

(4) Within 10 minutes from applying heat at 0.2 W to the heat source, an equilibrium state (temperature change within 0.05° C.) is achieved at each of the seven constantly arranged points, and the equilibrium state is maintained for 2 minutes or more If so, it was judged that the fluid and gas inside the vapor chamber circulate well and heat transfer was performed well. Whether an equilibrium state was achieved by increasing the temperature of the heat source by 0.1 °C from 20 °C was evaluated, and the highest temperature among the equilibrium states was set as the maximum temperature.

The measurement of the maximum temperature was described by adding or subtracting the maximum temperature of the remaining Preparation Examples based on the maximum temperature measured in the vapor chamber of Comparative Example 1.

Example 1. Fabrication of the vapor chamber

A vapor chamber was manufactured through the following process. The process is simplified and illustrated in FIG. 8 .

(1) A slurry is prepared using copper (Cu) powder having an average particle diameter (D50 particle diameter) of about 10 μm to 20 μm as a metal component. As a dispersant, ethylene glycol (EG) and ethyl cellulose (EC) as a binder are mixed in a 4:5 weight ratio (EG:EC) of the copper powder, and the binder and copper powder are mixed in a weight ratio of about 10:1 (Cu:EC) is mixed to prepare a slurry.

(2) A frame (printing area is After positioning (width 18mm, length 72mm), the slurry prepared in (1) is applied and the slurry is printed on copper foil to have a specific pattern.

(3) Dry the printed slurry at 120°C for 30 minutes using a dryer.

(4) The dried slurry is sintered at 1,000° C. for 1 hour using a sintering furnace to prepare a metal foam.

(5) Lay the copper foil of the same size as prepared in (2) on the copper foil prepared with metal foam so that the metal foam exists in the inner space between both copper foils, and then combine the remaining edges except the injection hole .

(6) Create a vacuum atmosphere in the inner space by supplying 50 μL of water (working fluid) through the inlet, injecting an inert gas through the inlet, and sealing the inlet using an epoxy resin.

Example 2. Fabrication of the vapor chamber

A vapor chamber was manufactured in the same manner as in Example 1, except that in the process (2) of Example 1, a frame prepared to print the shape of the closed space 300 shown in FIG. 5 was applied.

Example 3. Fabrication of the vapor chamber

A vapor chamber was manufactured in the same manner as in Example 1, except that in the process (2) of Example 1, a frame prepared to print the shape of the closed space 300 shown in FIG. 6 was applied.

Example 4. Preparation of vapor chamber

A vapor chamber was manufactured in the same manner as in Example 1, except that in the process (2) of Example 1, a frame prepared to print the shape of the closed space 300 shown in FIG. 7 was applied.

Comparative Example 1. Preparation of steam chamber

A vapor chamber was manufactured in the same manner as in Example 1, except that in the process (2) of Example 1, a frame prepared to print the shape of the closed space 300 shown in FIG. 3 was applied.

Comparative Example 2. Preparation of steam chamber

A vapor chamber was manufactured in the same manner as in Example 1, except that in the process (2) of Example 1, a frame prepared to print the shape of the closed space 300 shown in FIG. 9 was applied.

The heat dissipation characteristics of the vapor chambers of Examples and Comparative Examples were evaluated through Relative Qmax and maximum temperature, and the results are summarized in Table 1 below.

Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 Relative Qmax (unit: W) 1.00 1.05 1.18 1.20 1.22 1.31 Max Temperature Refresh +1 +4 +4.3 +5.2 +6

Referring to Table 1, an embodiment of a vapor chamber having a structure in which a vapor flow passage is partitioned by a liquid passage in the evaporation region, and a comparative example in which the vapor passage is not partitioned by a liquid passage in the evaporation region It can be seen that the better heat dissipation performance is exhibited. In addition, it was confirmed that the vapor chamber of the example has a higher operating temperature range compared to the vapor chamber of the comparative example. Accordingly, it can be seen that the vapor chamber of the embodiment can more effectively suppress the dry-out phenomenon than the vapor chamber of the comparative example.

10: vapor chamber
100: first substrate
200: second substrate
300: enclosed space
310: liquid flow path part
311, 311a, 311b, 311c: center wick
312: wick around
313a, 313b: bent part
314a, 314b: points at which the peripheral wick extends from the central wick
320: steam flow passage
330: evaporation area

Claims (17)

a first substrate; a second substrate facing the first substrate; and a closed space positioned between the first substrate and the second substrate and encapsulated in a working fluid,
A plurality of vapor passage portions through which the vapor of the working fluid evaporated by an external heat source passes and a liquid passage portion through which the liquid working fluid passes are formed in the sealed space,
The enclosed space includes an evaporation area in which the working fluid is evaporated by an external heat source,
A vapor chamber in which at least two vapor passage portions are partitioned by a liquid passage portion in an evaporation region. The vapor chamber of claim 1 , wherein the first substrate and the second substrate are each a metal substrate. The method of claim 1,
The liquid flow passage includes a central wick disposed along a direction transverse to the evaporation region; and
A vapor chamber comprising at least one peripheral wick extending from the central wick along a direction away from the vaporization region. 4. The method of claim 3,
at least one peripheral wick extends along a first direction;
The at least one peripheral wick extends in a second direction opposite the first direction to the vapor chamber. 4. The vapor chamber of claim 3, wherein the plurality of vapor passage portions and the at least one peripheral wick are alternately arranged. 5. The method of claim 4,
wherein at least two peripheral wicks are symmetrical with respect to the central wick. The method of claim 1,
The liquid flow passage includes: a plurality of central wicks disposed apart from each other in a direction transverse to the evaporation region; and
one or more peripheral wicks extending from each central wick along a direction away from the evaporation region;
a vapor chamber in which at least two central wicks are fluidly connected through peripheral wicks. 4. The method of claim 3,
The central wick is a vapor chamber containing a bend bent along a direction transverse to the evaporation region. 9. The method of claim 8,
At least one peripheral wick extends from a bend in the central wick vapor chamber. 5. The method of claim 4,
The peripheral wick extending in the first direction and the peripheral wick extending in the second direction each extend at different points of the central wick. The vapor chamber of claim 1 , wherein the liquid passage portion occupies a range of 5% to 90% of the volume of 100% of the sealed space. The vapor chamber of claim 1 , wherein the liquid passage part is a porous metal layer including thermally conductive metal particles. 13. The method of claim 12, wherein the thermally conductive metal particles are any one or 2 selected from the group consisting of iron particles, cobalt particles, copper particles, gold particles, aluminum particles, silver particles, nickel particles, molybdenum particles, platinum particles and magnesium particles. A vapor chamber that is a mixture of more than one. The vapor chamber of claim 12 , wherein the thermally conductive metal particles have an average particle diameter in a range of 100 nm to 200 μm. The vapor chamber of claim 1 , wherein the liquid passage portion has an average pore size of 100 μm or less. The vapor chamber of claim 1 , wherein the liquid passage part is a porous metal layer having a porosity of 30% or more. The vapor chamber according to claim 15, wherein the filling rate (R) of the working fluid enclosed in the sealed space satisfies the following general formula (1):
[General formula 1]
30 ≤ R (%) = (Lv / Wv) * 100 ≤ 200
In Formula 1, R is the filling rate of the working fluid enclosed in the sealed space, Lv is the volume of the working fluid enclosed in the sealed space, and Wv is the volume of pores in the liquid passage part existing in the sealed space.

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