WO2022025257A1

WO2022025257A1 - Heat conducting member

Info

Publication number: WO2022025257A1
Application number: PCT/JP2021/028352
Authority: WO
Inventors: 征志高尾; 仕▲ゆ▼ 楊; 敏彦小関; 雅昭花野; 淳一石田
Original assignee: 日本電産株式会社; 尼得科超▲しゅう▼科技股▲ふん▼有限公司
Priority date: 2020-07-31
Filing date: 2021-07-30
Publication date: 2022-02-03

Abstract

This heat conducting member comprises a housing having an inner space, a wick structure, and a working medium. The housing has a column part disposed in the inner space. The wick structure and the working medium are accommodated in the inner space. The heat conducting member satisfies the following:　V1>V2, where V1 is the volume of a steam space which is included in a space other than the wick structure in the inner space and in which steam of the working medium can exist, and V2 is the volume of the wick structure.

Description

Heat conduction member

The present invention relates to a heat conductive member.

The conventional heat conductive member has a flat plate-shaped closed container, a porous sheet, and a working fluid. The flat plate-shaped closed container has an inside. The porous sheet is arranged on the inner surface of the flat plate-shaped closed container. The working fluid is housed inside. It was

The flat plate-shaped closed container is arranged in contact with the heating element. The porous sheet may have a porous sheet on the heating element side and a porous sheet on the cooling side opposite to the heating element side. The working fluid is heated by the heating element and vaporized from the porous sheet on the heating element side. The working fluid vaporized into steam diffuses in the gap space between the two porous sheets and condenses in the cooling side porous sheet. As a result, heat is transferred from the heating element side to the cooling side (see, for example, Patent Document 1).

Japanese Publication: Japanese Patent Application Laid-Open No. 2002-62072

However, the heat conductive member as described above has a problem that the vapor of the working fluid is difficult to diffuse in the flat plate-shaped closed container, and the heat transport efficiency tends to decrease. It was

In view of the above situation, it is an object of the present invention to provide a heat conductive member capable of improving heat transport efficiency.

An exemplary thermal conductive member of the present invention comprises a housing with an internal space, a wick structure, and a working medium. The housing has a pillar portion arranged in the internal space. The wick structure and the working medium are housed in an internal space. The heat conductive member satisfies the following.

V1> V2

V1: Volume of the steam space contained in the space other than the wick structure in the internal space and in which the steam of the working medium can exist.

V2: Volume of wick structure

According to the exemplary heat conductive member of the present invention, heat transport efficiency can be improved.

FIG. 1 is a perspective view of a heat conductive member according to an embodiment of the present invention. FIG. 2 is a schematic side sectional view of the heat conductive member according to the embodiment of the present invention. FIG. 3 is a schematic side sectional view of the heat conductive member according to the modified example of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In the drawings, the XYZ coordinate system is shown as a three-dimensional Cartesian coordinate system as appropriate. In the XYZ coordinate system, the Z-axis direction indicates the vertical direction, the + Z direction is the upper side, and the −Z direction is the lower side. The Z-axis direction is also the opposite direction between the first metal plate 11 and the second metal plate 12, which will be described later. The X-axis direction refers to a direction orthogonal to the Z-axis direction, and one direction and the opposite direction thereof are the + X direction and the −X direction, respectively. The Y-axis direction refers to a direction orthogonal to both the Z-axis direction and the X-axis direction, and one direction and the opposite direction thereof are the + Y direction and the −Y direction, respectively. The vertical direction may be, for example, a vertical direction. In that case, the upper side is in the direction opposite to the direction of gravity, and the lower side is in the direction of gravity. However, the vertical direction is not limited to the vertical direction. It was

Further, in the present specification, "sintering" refers to a technique of heating a metal powder or a metal powder to a temperature lower than the melting point of the metal to bake and harden the metal particles. Further, the "sintered body" refers to an object obtained by sintering. It was

<1. Structure of heat conductive member>

FIG. 1 is a perspective view of a heat conductive member 1 according to an exemplary embodiment of the present invention, and FIG. 2 is a schematic side sectional view of the heat conductive member 1. Note that FIG. 2 is a cross-sectional view taken along the alternate long and short dash line AA of FIG. The heat conductive member 1 is also called a vapor chamber and transports the heat of the heating element H. Examples of the heating element H include a power transistor of an inverter provided in a traction motor for driving a wheel of a vehicle. The power transistor is, for example, an IGBT (Insulated Gate Bipolar Transistor). In this case, the heat conductive member 1 is mounted on the traction motor. The calorific value of the IGBT is generally 100 W or more.

A heating element H is arranged in contact with the lower surface of the heat conductive member 1. The heat generated by the heating element H is dissipated from the upper surface of the heat conductive member 1. In order to improve heat dissipation, heat dissipation fins such as stacked fins and pin fins may be provided on the upper surface of the heat conductive member 1. In that case, a cooling medium is passed between the heat radiation fins. The cooling medium may be, for example, water, oil, or air. It was

In the configuration shown in FIGS. 1 and 2, as an example, one heating element H is arranged at the center of the lower surface of the rectangular heat conductive member 1. However, the heating element H may be arranged on the lower surface edge portion of the heat conductive member 1. Further, a plurality of heating elements may be arranged on the lower surface of the heat conductive member 1. It was

The thickness of the heat conductive member 1 in the Z direction is, for example, 5 mm or more. The heat conductive member 1 includes a housing 10, a working medium 20, and a wick structure 30. It was

<2. Housing configuration>

The housing 10 has an internal space 10a. The working medium 20 and the wick structure 30 are housed in the internal space 10a. The housing 10 has a pillar portion 15 arranged in the internal space 10a. The housing 10 has a first metal plate 11 and a second metal plate 12 arranged so as to face each other.

The first metal plate 11 and the second metal plate 12 are formed of a metal having high thermal conductivity such as copper. Further, it may be formed by plating the surface of a metal other than copper with copper. As the metal other than copper, for example, stainless steel can be considered. It was

The first metal plate 11 and the second metal plate 12 have a rectangular plate shape that extends in the horizontal direction when viewed from above. The heating element H comes into contact with the lower surface of the second metal plate 12. That is, the second metal plate 12 is arranged on the heating element H side. The first metal plate 11 covers the upper surface of the second metal plate 12. The first metal plate 11 and the second metal plate 12 of the present embodiment are rectangular in top view, but the present invention is not limited to this. For example, it may be polygonal or circular in top view. It was

The first metal plate 11 has a first side wall portion 13a extending downward from the peripheral edge. The second metal plate 12 has a second side wall portion 13b extending upward from the peripheral edge. The lower surface of the first side wall portion 13a and the upper surface of the second side wall portion 13b are joined at the joint portion 14. The lower surface of the first side wall portion 13a and the upper surface of the second metal plate 12 may be joined by omitting the second side wall portion 13b. Alternatively, the upper surface of the second side wall portion 13b and the lower surface of the first metal plate 11 may be joined by omitting the first side wall portion 13a. It was

The internal space 10a is formed by being surrounded by the first metal plate 11 and the second metal plate 12. The internal space 10a is a closed space, and is maintained in a decompressed state where the atmospheric pressure is lower than the atmospheric pressure, for example. When the internal space 10a is in a decompressed state, the working medium 20 housed in the internal space 10a is likely to evaporate. The working medium 20 is, for example, water, but may be another liquid such as alcohol. It was

The joint 14 is located around the wick structure 30 in top view. The method of joining the first side wall portion 13a and the second side wall portion 13b is not particularly limited. For example, any joining method such as a method of joining by applying heat and pressure, a diffusion joining, or a joining using a brazing material may be used. It was

The joint portion 14 may include a sealing portion. The sealing portion is, for example, a portion where an injection port for injecting the working medium 20 into the housing 10 is sealed by welding in the manufacturing process of the heat conductive member 1. It was

The pillar portion 15 has at least one solid solid pillar portion 151. The solid pillar portion 151 is a separate member from the first metal plate 11 and the second metal plate 12. The solid pillar portion 151 connects the first metal plate 11 and the second metal plate 12. As a result, the solid pillar portion 151 supports the first metal plate 11 and the second metal plate 12. The "solid" member means that it is a so-called solid member, and the contents are tightly packed and not porous. For example, a "solid" member may be a member that does not have a cavity inside, or a member that has one or more macroscopic cavities inside. It was

The solid column portion 151 is formed of a metal having high thermal conductivity such as copper. The solid pillar portion 151 extends in the Z-axis direction, and the upper end portion and the lower end portion of the solid pillar portion 151 are joined to the lower surface of the first metal plate 11 and the upper surface of the second metal plate 12, respectively, using a brazing material. To. The solid column portion 151 may be joined to the first metal plate 11 and the second metal plate 12 by welding or the like, in addition to joining with a brazing material. Further, the solid pillar portion 151 may be integrated with one of the first metal plate 11 and the second metal plate 12. At this time, the solid pillar portion 151 can be formed when the first metal plate 11 or the second metal plate 12 is formed by etching or cutting. It was

The solid pillar portion 151 is composed of, for example, a circular cylinder in a top view. The solid pillar portions 151 are two-dimensionally and regularly arranged side by side in the XY plane. By supporting the first metal plate 11 and the second metal plate 12 by the pillar portion 15 in the Z-axis direction, the thickness of the housing 10 in the Z-axis direction is kept constant. As a result, it is possible to prevent the internal space 10a from becoming narrow due to the deformation of the housing 10 in the Z-axis direction. It was

The pillar portion 15 further includes at least one connecting pillar portion 152. The connecting pillar portion 152 is a pillar. The connecting pillar portion 152 extends in the Z-axis direction and is composed of, for example, a circular cylinder in a top view. Further, the connecting pillar portions 152 are two-dimensionally and regularly arranged side by side in the XY plane. The connecting column portion 152 is preferably arranged in the middle of the adjacent solid column portions 151. It was

<3. Structure of wick structure>

The wick structure 30 has a first wick structure portion 31, a second wick structure portion 32, and at least one connecting column portion 152.

The first wick structure portion 31, the second wick structure portion 32, and the connecting column portion 152 are porous and have a gap portion (not shown) forming a flow path of the working medium 20. The first wick structure portion 31 is a plate-shaped member arranged on the inner surface of the first metal plate 11, and is arranged on the cooling side opposite to the heating element H side. The second wick structure portion 32 is a plate-shaped member arranged on the inner surface of the second metal plate 12, and is arranged on the heating element H side. The first wick structure portion 31 and the second wick structure portion 32 are arranged so as to face each other. A vapor space S is formed between the first wick structure portion 31 and the second wick structure portion 32. The steam space S is a space for diffusing the steam of the working medium 20. It was

The connecting pillar portion 152 connects the first wick structure portion 31 described later and the second wick structure portion 32 described later. The connecting column portion 152 supports the first metal plate 11 and the second metal plate 12 via the first wick structure portion 31 and the second wick structure portion 32. As a result, the connecting pillar portion 152 can reinforce the solid pillar portion 151 and further suppress the deformation of the housing 10 in the Z-axis direction. It was

Further, the first wick structure portion 31, the second wick structure portion 32, and the connecting column portion 152 are porous sintered bodies, respectively, and are integrated with each other. By making the first wick structure portion 31, the second wick structure portion 32, and the connecting column portion 152 into a porous sintered body, it can be manufactured more easily than the mesh material, and the heat conductive member 1 can be manufactured. The cost can be reduced. Further, by providing the connecting pillar portion 152, the flow path of the operating medium 20 from the first wick structure portion 31 to the second wick structure portion 32 can be increased. It was

The thickness W2 of the second wick structure portion 32 is preferably larger in the Z direction than the thickness W1 of the first wick structure portion 31. The second wick structure portion 32 arranged on the heating element H side promotes the vaporization of the liquid working medium 20 as compared with the first wick structure portion 31. Therefore, by making the thickness W2 of the second wick structure portion 32 larger in the Z direction than the thickness W1 of the first wick structure portion 31, the holding property of the operating medium 20 of the second wick structure portion 32 is improved. It can be made higher than the holding property of the working medium 20 of the first wick structure portion 31. As a result, a dryout occurs in which all the working medium 20 contained in the second wick structure 32 is vaporized before the vaporized working medium 20 is condensed by heat dissipation and returned to the second wick structure 32. Can be suppressed. It was

Further, in the Z direction, the length of the gap between the thickness W1 of the first wick structure portion 31, the thickness W2 of the second wick structure portion 32, and the first wick structure portion 31 and the second wick structure portion 32. It is preferable that W3 satisfies the formula (1). It was

W3> W2 + W1 ... (1)

In the internal space 10a, the working medium 20 vaporized from the second wick structure portion 32 is provided in the internal space 10a by providing a large gap in the Z direction between the first wick structure portion 31 and the second wick structure portion 32. It becomes easy to diffuse in the XY plane inside. This promotes the condensation of the working medium 20 in the first wick structure portion 31. It was

Further, in the Z direction, the length of the gap between the thickness W1 of the first wick structure portion 31, the thickness W2 of the second wick structure portion 32, and the first wick structure portion 31 and the second wick structure portion 32. It is more preferable that W3 satisfies the equations (2) to (4). It was

4W1 ≧ W2 ≧ 2 W1 ・・・ (2)

7W1 ≧ W3 ≧ 5 W1 ・・・ (3)

W3 + W2 = 9W1 ... (4)

That is, the sum of the length W3 of the gap between the first wick structure portion 31 and the second wick structure portion 32 and the thickness W2 of the second wick structure portion 32 is the thickness W1 of the first wick structure portion 31. The thickness W2 of the second wick structure portion 32 is set to be twice or more and four times or less the thickness W1 of the first wick structure portion 31, and the thickness W2 of the first wick structure portion 31 and the second wick structure is equal to or less than 9 times. It is preferable that the length W3 of the gap with the body portion 32 is 5 times or more and 7 times or less the thickness W1 of the first wick structure portion 31. This makes it possible to further promote the condensation of the working medium 20 in the first wick structure 31 while ensuring the holding property of the working medium 20 in the second wick structure 32. The

Further, the first wick structure portion 31 arranged on the cooling side opposite to the heating element H promotes the condensation of the vaporized working medium 20 as compared with the second wick structure portion 32. Therefore, it is preferable that the first wick structure portion 31 has a higher cooling efficiency of the working medium 20 than the second wick structure portion 32. It was

Further, the second wick structure portion 32 has a higher porosity than the first wick structure portion 31. As a result, the capillary force of the second wick structure portion 32 becomes larger than the capillary force of the first wick structure portion 31. It was

Here, the ratio of the volume of the space to the total product of the first wick structure portion 31 and the second wick structure portion 32 is referred to as a porosity. The unit of porosity is%. The porosity is determined by the following method. For example, the porosity can be obtained by measuring the area of the space from the cross-sectional photograph of the wick structure portion and calculating the ratio of the area of the space to the whole. When observing the cross sections of the first wick structure portion 31 and the second wick structure portion 32, it is preferable to use a scanning electron microscope having a deep depth of field. The method of observing the cross section is not particularly limited as long as it can easily distinguish between the metal portion and the space. It was

In the present embodiment, the first wick structure portion 31 and the second wick structure portion 32 are made of a porous sintered body, but the first wick structure portion 31 or the second wick structure portion is formed. 32 may be a mesh member in which a plurality of metal linear members are woven. By forming the second wick structure portion 32 with a mesh material and the first wick structure portion 31 with a porous sintered body, the capillary force of the second wick structure portion 32 can be reduced to the first wick structure. It can be easily increased more than the capillary force of the body 31. It was

Further, the first wick structure portion 31 may have a configuration having a plurality of groove portions. As a result, the holding property of the working medium 20 of the first wick structure portion 31 arranged on the cooling side can be lowered, and the condensed working medium 20 can be promoted to return to the heating element H side. It was

The first wick structure portion 31, the second wick structure portion 32, and the connecting column portion 152 are formed, for example, as follows. First, a mixed powder containing micro copper particles, a copper body and a resin is sprayed and applied to the lower surface of the first metal plate 11 and the upper surface of the second metal plate 12 before joining. Next, the first metal plate 11 and the second metal plate 12 are joined by sandwiching the mixed powder formed in a columnar shape. After that, the housing 10 is heated to bake the mixed powder. As a result, the first wick structure portion 31, the second wick structure portion 32, and the connecting pillar portion 152 can be easily integrally formed in the internal space 10a of the housing 10. As a result, the manufacturing cost of the heat conductive member 1 can be suppressed. The first metal plate 11 and the second metal plate 12 may be joined after the first wick structure portion 31, the second wick structure portion 32, and the connecting column portion 152 are fired separately. It was

In addition, in this specification, "coating" means adhering metal powder to the lower surface of the first metal plate 11 and the upper surface of the second metal plate 12. In addition to the spray application method, a paste containing metal powder may be applied. It was

Micro copper particles are particles in which a plurality of copper atoms are aggregated or bonded. The particle size of the micro copper particles is 1 μm or more and less than 1 mm. The micro copper particles are, for example, porous. It was

The copper body is a copper melt obtained by melting and solidifying sub-micro copper particles smaller than the micro copper particles by sintering. Submicro copper particles are particles in which a plurality of copper atoms are aggregated or bonded. The particle size of the sub-micro copper particles before melting is 0.1 μm or more and less than 1 μm. It was

The resin is a volatile resin that volatilizes at a temperature below the melting point of the copper constituting the micro copper particles and the copper body. As such a volatile resin, for example, a cellulose resin such as methyl cellulose or ethyl cellulose, an acrylic resin, a butyral resin, an alkyd resin, an epoxy resin, a phenol resin or the like can be used. Among these, it is preferable to use an acrylic resin having high thermal decomposability. It was

<4. Operation of heat conductive member>

In FIG. 2, the flow of steam generated by vaporizing the working medium 20 is indicated by a black arrow in the heat conductive member 1, and the flow of the liquid working medium 20 is indicated by a white arrow in the heat conductive member 1.

In the heat conductive member 1 having the above configuration, when the temperature of the second metal plate 12 rises due to the heat generated by the heating element H, the liquid working medium 20 contained in the second wick structure portion 32 is vaporized. .. It was

The working medium 20 that has been vaporized into steam diffuses in the steam space S. The steam space S is a space excluding the space occupied by the solid pillar portion 151 and the connecting pillar portion 152 from the gap space between the first wick structure portion 31 and the second wick structure portion 32. be. It was

At this time, a part of the vaporized working medium 20 comes into contact with the first wick structure portion 31 to be cooled and condensed. The surface area of the first wick structure portion 31 is larger than that of the lower surface of the first metal plate 11, and the cooling efficiency is high. Therefore, by providing the first wick structure portion 31, the cooling efficiency of the vaporized working medium 20 is improved and condensation is promoted. It was

A part of the working medium 20 condensed in the first wick structure portion 31 is dropped and absorbed by the second wick structure portion 32. Further, a part of the working medium 20 condensed in the first wick structure portion 31 moves in the first wick structure portion 31 and in the connecting column portion 152 and is absorbed by the second wick structure portion 32. Further, a part of the working medium 20 condensed in the first wick structure portion 31 moves along the outer surface of the pillar portion 15 and is absorbed by the second wick structure portion 32. It was

At this time, since the capillary force of the second wick structure portion 32 is higher than the capillary force of the first wick structure portion 31, the condensed working medium 20 is passed through the second wick structure portion 32 by the heating element H. It can be moved to the position where it is placed faster. Therefore, the heat transport efficiency by the working medium 20 is improved. It was

As described above, the working medium 20 moves while changing its state, so that heat is continuously transferred from the heating element H side to the cooling side. It was

<5. About steam space ＞

As described above, the steam space S excludes the space occupied by the solid pillar portion 151 and the connecting pillar portion 152 from the gap space between the first wick structure portion 31 and the second wick structure portion 32. It is a space. That is, the steam space S is included in the space other than the wick structure 30 in the internal space 10a, and is a space in which the steam of the working medium 20 can exist.

Then, in this embodiment, the following equation (5) is satisfied.

V1> V2 ... (5)

However, V1: the volume of the vapor space S, V2: the volume of the wick structure 30.

By doing so, it is possible to secure the volume of the steam space S and promote the diffusion of the steam of the working medium 20. Therefore, the heat transport efficiency of the heat conductive member 1 can be improved. It was

Further, the steam space S is a space other than the wick structure 30 and at least one solid pillar portion 151 in the internal space 10a. Although the solid pillar portion 151 can secure the strength of the housing 10, arranging the solid pillar portion 151 causes the steam space S to become narrower, and even when such a solid pillar portion 151 is provided, the above equation (5) can be used. By filling, the diffusion of steam can be promoted. It was

Further, from the above equation (5), the volume of the steam space S is larger than the sum of the volumes of the first wick structure portion 31, the second wick structure portion 32, and the connecting pillar portion 152, so that the steam is vaporized. Can promote the spread of. It was

<6. Pillar part and 3rd wick structure part>

In the present embodiment, it is preferable that the solid pillar portion 151 and the connecting pillar portion 152 of the pillar portion 15 have the following configurations.

The total joint area where the upper surface of the solid column portion 151 and the lower surface of the first metal plate 11 are joined is the joint area where the upper surface of the connecting column portion 152 and the lower surface of the first wick structure portion 31 are joined. Greater than the sum. The total joint area where the lower surface of the solid column portion 151 and the upper surface of the second metal plate 12 are joined is the joint where the lower surface of the connecting column portion 152 and the upper surface of the second wick structure portion 32 are joined. It is larger than the total area. The total joint area is the total number of joint areas of one solid column portion 151 or the connecting column portion 152. It was

However, as shown in the modified example in FIG. 3, the connecting column portion 152 penetrates the first wick structure portion 31 and is joined to the first metal plate 11 and also penetrates the second wick structure portion 32. It may be joined to the second metal plate 12. In such a case, the total joint area where the upper surface of the solid pillar portion 151 and the lower surface of the first metal plate 11 are joined is such that the upper surface of the connecting pillar portion 152 and the lower surface of the first metal plate 11 are joined. It is larger than the total joint area to be formed. Moreover, the total joint area where the lower surface of the solid pillar portion 151 and the upper surface of the second metal plate 12 are joined is the joint area where the lower surface of the connecting pillar portion 152 and the upper surface of the second metal plate 12 are joined. Greater than the sum. It was

That is, the total contact area of the solid pillar portion 151 where one side end is in contact with the first metal plate 11 is such that the one side end of the connecting pillar portion 152 is the first wick structure portion 31 or the first metal plate 11. The total contact area is wider than the total contact area and the other side end of the solid pillar portion 151 is in contact with the second metal plate 12, and the other side end of the connecting pillar portion 152 is the second wick structure. It is wider than the total contact area in contact with the portion 32 or the second metal plate 12. It was

The strength of the solid column portion 151 is higher than the strength of the connecting column portion 152. Therefore, due to the magnitude relationship of the contact area as described above, the strength of the housing 10 can be sufficiently secured by the solid pillar portion 151 even in the configuration using the connecting pillar portion 152. It was

<7. Others>

The embodiment of the present invention has been described above. The scope of the present invention is not limited to the above-described embodiment. The present invention can be implemented by making various modifications to the above-described embodiments without departing from the gist of the invention. In addition, the items described in the above-described embodiments can be arbitrarily combined as long as they do not cause a contradiction.

For example, one of the first wick structure portion 31 and the second wick structure portion 32 may not be provided. Alternatively, at least one of the solid pillar portion 15 and the connecting pillar portion 152 may not be provided. It was

The present invention can be used for cooling various heating elements.

1 heat conductive member 10 housing 10a internal space 11 1st metal plate 12 2nd metal plate 13a 1st side wall 13b 2nd side wall 14 joint 15 pillar part 151 solid pillar part 152 Structure 31 1st wick structure part 32 2nd wick structure part H heat generating body S steam space

Claims

A housing with an internal space and

With the wick structure,

With a working medium,

The housing has a pillar portion arranged in the internal space, and the housing has a pillar portion.

The wick structure and the working medium are housed in the internal space.

A heat conductive member that satisfies the following.

V1> V2

V1: Volume of the steam space contained in the space other than the wick structure in the internal space and in which the steam of the working medium can exist.

V2: Volume of the wick structure
The housing is

It has a first metal plate and a second metal plate arranged to face each other, and has.

The pillar portion has at least one solid solid pillar portion and has at least one solid solid pillar portion.

The solid pillar portion connects the first metal plate and the second metal plate, and forms the solid pillar portion.

The heat conductive member according to claim 1, wherein the steam space is a space other than the wick structure and at least one pillar portion in the internal space.
The wick structure is

It has a first wick structure portion and a second wick structure portion arranged so as to face each other.

The heat conductive member according to claim 1, wherein the pillar portion further has at least one connecting pillar portion that connects the first wick structure portion and the second wick structure portion.
The wick structure is

It has a first wick structure portion and a second wick structure portion arranged so as to face each other.

The heat conductive member according to claim 2, wherein the pillar portion further has at least one connecting pillar portion that connects the first wick structure portion and the second wick structure portion.
The total contact area of one end of the solid pillar portion in contact with the first metal plate is the contact in which one end of the connecting pillar portion is in contact with the first wick structure portion or the first metal plate. The total area is wider than the total area, and the total contact area where the other end of the solid pillar is in contact with the second metal plate is such that the other end of the connecting column is the second wick structure. The heat conductive member according to claim 4, which is wider than the total contact area in contact with the second metal plate.
The second wick structure portion is arranged on the heating element side.

The heat conductive member according to any one of claims 3 to 5, wherein the first wick structure portion has a plurality of groove portions.
The heat conductive member according to any one of claims 3 to 6, wherein the connecting column portion is a porous sintered body.
The second wick structure portion is arranged on the heating element side.

The heat conductive member according to any one of claims 3 to 7, wherein the thickness of the second wick structure portion is larger than the thickness of the first wick structure portion.
The heat conductive member according to any one of claims 3 to 8, wherein the first wick structure portion is a porous sintered body.
The heat conductive member according to any one of claims 3 to 9, wherein the second wick structure portion is a mesh member in which a plurality of metal linear members are woven.
The heat conductive member according to any one of claims 3 to 9, wherein the second wick structure portion is a porous sintered body.
The heat conductive member according to any one of claims 3 to 10, wherein the first wick structure portion, the second wick structure portion, and the connecting pillar portion are integrated.
The heat conductive member according to any one of claims 3 to 12, wherein the second wick structure portion has a higher porosity than the first wick structure portion.
The heat conductive member according to any one of claims 3 to 13, wherein the capillary force of the second wick structure portion is higher than the capillary force of the first wick structure portion.