Heat transfer body, heat exchange unit, and heat transfer body mounting method

Abstract

To provide a heat transfer body, a heat exchange unit, and a heat transfer body attaching method which can provide a base material with flexibility and followability to a body to be heated, and can have an appropriate heat transfer effect.SOLUTION: A heat transfer body 10 includes a base material 20 which contains at least metal fibers and should be attached to a body to be heated, and a heat transfer part 30 a part of which is fused to the metal fibers of the base material 20 and another part of which is exposed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heat transfer body for transferring heat to or from a heat transfer object, a heat exchange unit including such a heat transfer body, and a method for attaching such a heat transfer body to the heat transfer object. [Background technology]

[0002] Various types of heat sinks and heat dissipation materials have been used to dissipate heat from objects to be cooled, such as heat-generating electrical and electronic components. Known examples of such heat sinks include a flat base and multiple plate-like members extending from the top surface of the base and arranged substantially parallel to one another. Another type of heat sink may include a flat base and multiple rod-like members extending from the top surface of the base and arranged at the intersections of lattice lines. In such heat sinks, at least the flat base is made of a solid material (i.e., a material that barely expands or contracts with temperature changes). Therefore, after a heat sink is attached to an object to be cooled, if the object expands or contracts due to changes in the external environment, the base of the heat sink cannot expand or contract in the same way as the object to be cooled. This creates a gap between the object and the heat sink, resulting in reduced cooling efficiency.

[0003] Furthermore, conventional heat sinks and the like are disclosed in Patent Documents 1 to 4. Here, the heat sinks and the like disclosed in Patent Documents 1 to 3 are generally flat. More specifically, the heat sink disclosed in Patent Document 1 is composed of an aggregate of at least one thermally conductive material selected from metal fibers, thin metal wires, metal foils, and ceramic fibers. Furthermore, the heat sinks and the like disclosed in Patent Documents 2 and 3 are composed of a flexible substrate (for example, one formed from a gel-like material).

[0004] Furthermore, the heat dissipation fin disclosed in Patent Document 4 has a flat base and a plurality of thin plate-like fins that stand upright on the upper surface of the base and are arranged substantially parallel to one another, and the base and the plurality of fins are integrally formed. In such a heat dissipation fin, when the substrate and each fin are viewed from the thickness direction, the fibrous filler is oriented in the planar direction in each of the base and each fin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 5-299545 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-101005 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-88171 [Patent Document 4] International Patent Application Publication WO2017 / 061307A1 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the heat sink disclosed in Patent Document 1 is composed of an aggregate of at least one thermally conductive material selected from metal fibers, fine metal wires, metal foil, and ceramic fibers. Therefore, gaps are formed within the heat sink, and the air trapped in these gaps provides thermal insulation. Furthermore, the heat sink disclosed in Patent Document 1 is flat. For these reasons, the heat sink disclosed in Patent Document 1 may not be able to sufficiently dissipate heat from the object being cooled. Furthermore, the heat sinks disclosed in Patent Documents 2 and 3 are not in contact with the object being cooled, and therefore may not be able to sufficiently dissipate heat from the object being cooled. Furthermore, the heat sink fin disclosed in Patent Document 4 is a paper molded body, which contains a thermosetting resin, a fibrous filler, and a powdered filler. In this case, the paper molded body is solid, and therefore, when the object being cooled expands or contracts due to changes in the external environment, the base of the heat sink cannot expand or contract in the same way as the object being cooled. This creates a gap between the object being cooled and the heat sink, potentially reducing cooling efficiency.

[0007] The present invention has been made in consideration of these points, and aims to provide a heat transfer body, a heat exchange unit, and a heat transfer body mounting method that can give the base material flexibility and the ability to conform to the object to be heat transferred, and that can achieve a sufficient heat transfer effect. [Means for solving the problem]

[0008] The heat transfer body of the present invention is characterized by comprising a substrate to be attached to an object to be heat transferred, the substrate including at least metal fibers, and a heat transfer portion having a portion fused to the metal fibers of the substrate and another portion exposed.

[0009] The heat exchange unit of the present invention is characterized by comprising a substrate containing at least metal fibers, a heat transfer portion having a portion fused to the metal fibers of the substrate and another portion exposed, and a heat transfer object to which the substrate is attached.

[0010] The heat transfer body mounting method of the present invention is characterized by comprising the steps of: preparing a heat transfer body having a substrate containing at least metal fibers and a heat transfer portion having a portion fused to the metal fibers of the substrate and the other portion exposed; and mounting the substrate of the heat transfer body to an object to be heat transferred. [Effects of the Invention]

[0011] According to the heat transfer element, heat exchange unit, and heat transfer element mounting method of the present invention, the base material can be made flexible and able to conform to the object to which heat is transferred, and a sufficient heat transfer effect can be obtained. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a perspective view of a heat transfer element according to an embodiment of the present invention; [Figure 2] FIG. 2 is a top view of the heat transfer body shown in FIG. [Figure 3] FIG. 2 is a side view of the heat transfer body shown in FIG. [Figure 4] 1. FIG. 4 is a diagram showing an example of a state in which rod-shaped members of a heat transfer portion are attached to a base material in the heat transfer body shown in FIG. 1 etc. FIG. [Figure 5] 1. FIG. 4 is a configuration diagram showing another example of the state in which each rod-shaped member of the heat transfer portion is attached to the base material in the heat transfer body shown in FIG. 1 etc. [Figure 6] 2 is a cross-sectional view of a heat exchange unit in which a base material of the heat transfer body shown in FIG. 1 etc. is attached to an object to be heat transferred. [Figure 7] FIG. 10 is a perspective view of a heat transfer body according to another example of the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figures 1 to 7 show a heat transfer body according to this embodiment and a heat exchange unit in which a base material of such a heat transfer body is attached to an object to be heat transferred. The heat transfer body according to this embodiment is attached to an object to be heat transferred, such as a heat-generating electric or electronic component, thereby dissipating heat from the object to be heat transferred. Furthermore, the heat transfer body according to this embodiment may be attached to the outer surface of a pipe through which a medium such as cooling water or cooling gas passes, thereby being used as part of a heat exchange unit that removes heat from the surrounding environment to provide cooling.

[0014] As shown in FIGS. 1 to 3, the heat transfer element 10 of this embodiment includes a flat substrate 20 to be attached to an object to be heat transferred, and a heat transfer section 30 composed of a plurality of rod-shaped members attached to the substrate 20. The substrate 20 contains at least metal fibers. Metal-coated fibers may be used as the metal fibers contained in the substrate 20. The metal fibers of the substrate 20 are at least one of wet or dry nonwoven fabrics, woven fabrics, meshes, etc. Preferably, a metal fiber nonwoven fabric in which the metal fibers are bonded together is used as the substrate 20.

[0015] Specific examples of metals constituting the metal fibers contained in the substrate 20 are not particularly limited, but may be selected from the group consisting of stainless steel, iron, copper, aluminum, bronze, brass, nickel, chromium, etc., or may be precious metals selected from the group consisting of gold, platinum, silver, palladium, rhodium, iridium, ruthenium, osmium, etc. Among these, copper fibers and aluminum fibers are preferred because they have excellent thermal conductivity and a good balance between rigidity and plastic deformability.

[0016] The case where a metal fiber nonwoven fabric in which fibers are bonded together is used as the substrate 20 will be described in detail below. The metal fiber nonwoven fabric may be composed solely of metal fibers, or may contain metal fibers and other materials (e.g., thermally conductive particles such as alumina particles) in addition to the metal fibers. Bonding of metal fibers refers to a state in which the metal fibers are physically fixed, and the portion where the metal fibers are physically fixed is called a bonded portion. In the bonded portion, the metal fibers may be directly fixed together, or some of the metal fibers may be indirectly fixed together via a component other than the metal component. Examples of components other than the metal component include polyolefin resins such as polyethylene resin and polypropylene resin, polyethylene terephthalate (PET) resin, polyvinyl alcohol (PVA) resin, polyvinyl chloride resin, aramid resin, nylon, and acrylic resin, as well as fibrous materials made of these resins. Furthermore, organic materials with binding and supporting properties for metal fibers can also be used in the bonded portion.

[0017] The average fiber diameter of the metal fibers can be set arbitrarily as long as it does not impair the uniformity of the nonwoven fabric, but is preferably in the range of 1 μm to 30 μm, and more preferably in the range of 2 μm to 20 μm. When the average fiber diameter of the metal fibers is 1 μm or more, the metal fibers have an appropriate rigidity, which tends to reduce the occurrence of clumps when the nonwoven fabric is made. When the average fiber diameter of the metal fibers is 30 μm or less, the metal fibers have an appropriate flexibility, which tends to facilitate the fibers' moderate crossing. It should be noted that a smaller average fiber diameter of the metal fibers, within a range that does not interfere with the formation of the nonwoven fabric, is preferable because it facilitates improving the uniformity of the metal fiber nonwoven fabric. Furthermore, the "average fiber diameter" in this specification refers to the average area diameter (e.g., the average value of 20 fibers) calculated by calculating the cross-sectional area of the metal fibers in any cross section perpendicular to the longitudinal direction of a metal fiber nonwoven fabric photographed with a microscope (e.g., calculated using known software) and then calculating the diameter of a circle having the same area as the cross-sectional area.

[0018] The cross-sectional shape perpendicular to the longitudinal direction of the metal fibers may be any of circular, elliptical, substantially rectangular, irregular, etc., but is preferably circular. Here, the circular cross section does not have to be a perfect circle, as long as it is a circular cross-sectional shape that is likely to produce a curved portion due to the stress applied in the production of the metal fiber nonwoven fabric.

[0019] The average fiber length of the metal fibers is preferably in the range of 1 mm to 10 mm, and more preferably in the range of 3 mm to 5 mm. It is preferable that the fiber length of the metal fibers is short within a range that does not interfere with the formation of a nonwoven fabric, as this facilitates improving the homogeneity of the metal fiber nonwoven fabric. If the average fiber length is in the range of 1 mm to 10 mm, for example, when producing a metal fiber nonwoven fabric by papermaking, the so-called metal fiber clumps are less likely to occur, making it easier to control the degree of dispersion of the metal fibers, and the metal fibers are appropriately entangled with each other, which also facilitates improving the handling strength of the metal fiber nonwoven fabric. In this specification, the "average fiber length" refers to the average value obtained by measuring 20 fibers under a microscope.

[0020] It should be noted that metal fiber woven fabric may be used instead of metal fiber nonwoven fabric as the substrate 20. Some metal fiber woven fabrics are stretchable, so when the substrate 20 made of such stretchable metal fiber woven fabric is used, the substrate 20 will expand and contract accordingly when the object to which the substrate 20 is attached expands and contracts. This makes it possible to prevent gaps from occurring between the substrate 20 and the object to which heat is transferred.

[0021] The thickness of the substrate 20 can be adjusted to any thickness, but is preferably within the range of 1 mm to 50 mm, and more preferably within the range of 2 mm to 10 mm. In this specification, the "thickness of the substrate 20" refers to the average value measured at any number of measurement points using an air-drop terminal type film thickness meter (for example, Mitutoyo's Digimatic Indicator ID-C112X).

[0022] The space factor of the metal fibers in the substrate 20 is preferably in the range of 5 to 50%, and more preferably in the range of 15 to 40%. When the space factor of the metal fibers is 5% or more, the amount of metal fibers is sufficient to obtain a suitable homogeneity. When the space factor of the metal fibers is 50% or less, not only is the suitable homogeneity obtained, but also the desired flexibility of the metal fiber nonwoven fabric is obtained. In this specification, the "space factor of the metal fibers in the substrate 20" refers to the ratio of the area where the metal fibers exist to the volume of the substrate 20.

[0023] The elongation (tensile elongation at break) of the substrate 20 according to JIS P8113 is preferably within a range of 50 ppm to 50,000 ppm, more preferably within a range of 100 ppm to 20,000 ppm, and even more preferably within a range of 200 ppm to 5,000 ppm. Having a suitable elongation, the substrate 20 can easily conform to the heat transfer target without buckling when bent around an object such as an insulating layer, due to the extra space around the bent portion of the substrate 20. Specifically, if the elongation of the substrate 20 is less than 100 ppm, the substrate 20 cannot conform to the heat transfer target even if the heat transfer target expands or contracts, which may result in a gap between the substrate 20 and the heat transfer target. On the other hand, if the elongation of the substrate 20 is greater than 50,000 ppm, the strength of the substrate 20 may be weakened or the heat conductivity of the substrate 20 may be impaired. The elongation of the substrate 20 is determined by the average fiber length and average fiber diameter of the metal fibers, the space factor of the metal fibers in the substrate 20, the distance between the metal fibers, and the like. In this specification, the "elongation of the substrate 20" refers to a value measured in accordance with JIS P8113 (ISO 1924-2). Specifically, the elongation can be determined by adjusting a test piece to have an area of 15 mm x 180 mm and measuring it using a tensile tester (manufactured by A&D Co., Ltd., product name: RTG1210) at a tension speed of 30 mm / min.

[0024] According to this embodiment, the substrate 20 contains at least the metal fibers described above, and therefore, it is possible to provide the substrate 20 with flexibility and the ability to conform to the object to which heat is transferred. Specifically, even if the object to which the substrate 20 is attached expands or contracts, the substrate 20 expands or contracts in accordance with the expansion or contraction of the object to which heat is transferred, thereby preventing the formation of a gap between the object to which heat is transferred and the substrate 20.

[0025] Next, the configuration of the heat transfer unit 30 will be described. As shown in FIGS. 1 to 3 , the heat transfer unit 30 has a plurality of rod-shaped members extending outward from the substrate 20, with each rod-shaped member positioned at an intersection of the grid lines. Each of these rod-shaped members is made of, for example, a metal. More preferably, the type of metal constituting the metal fibers contained in the substrate 20 is the same as the type of metal constituting each rod-shaped member of the heat transfer unit 30. In this case, since the substrate 20 and the heat transfer unit 30 are made of the same type of metal, interfacial corrosion between the substrate 20 and the heat transfer unit 30 can be suppressed. In other words, if the type of metal constituting the metal fibers contained in the substrate 20 is different from the type of metal constituting each rod-shaped member of the heat transfer unit 30, a potential difference between the two metals could cause a current to flow, potentially resulting in the formation of holes in the metal.

[0026] As described above, it is preferable that the type of metal constituting the metal fibers contained in the substrate 20 is the same as the type of metal constituting each rod-shaped member of the heat transfer section 30, but this embodiment is not limited to this. In another embodiment, a heat transfer body 10 may be used in which the type of metal constituting the metal fibers contained in the substrate 20 is different from the type of metal constituting each rod-shaped member of the heat transfer section 30.

[0027] 3 and 4, each rod-shaped member constituting the heat transfer section 30 has a portion fused to the metal fibers of the substrate 20, and the other portion is exposed. As shown in FIG. 4, the end of each rod-shaped member constituting the heat transfer section 30 may extend to a position halfway through the substrate 20 in the thickness direction of the substrate 20. Alternatively, as shown in FIG. 5, each rod-shaped member constituting the heat transfer section 30 may penetrate the substrate 20. In this specification, "fused to the metal fibers of the substrate 20" includes sintering, bonding with a heat-conductive material, and the like.

[0028] For example, the length of each rod-shaped member constituting the heat transfer section 30 is preferably within a range of 0.5 to 50 mm, and more preferably within a range of 1 to 30 mm. Even more preferably, the length of each rod-shaped member constituting the heat transfer section 30 is within a range of 5 to 20 mm. Furthermore, the diameter of each rod-shaped member constituting the heat transfer section 30 is preferably within a range of 0.1 to 5 mm, and more preferably within a range of 0.5 to 3 mm. A sufficient heat transfer effect can be obtained within this range.

[0029] A method for manufacturing the heat transfer element 10 including the substrate 20 and heat transfer portion 30 will now be described. First, metal fibers and the like are dispersed in water to obtain a papermaking slurry. Next, the obtained papermaking slurry is poured into a batch-type papermaking machine. Then, rod-shaped members that will become the heat transfer portion 30 are placed in the tank of the batch-type papermaking machine into which the papermaking slurry has been poured, with their lower parts in contact with the papermaking screen and their upper parts fixed. The water is then filtered to obtain the heat transfer element 10, in which the rod-shaped members of the heat transfer portion 30 stand in the normal direction to the substrate 20, which contains at least metal fibers. Alternatively, after filtering the water, the rod-shaped members that will become the heat transfer portion 30 may be placed upright on the substrate 20. Then, while maintaining the rod-shaped members of the heat transfer portion 30 standing in the normal direction to the substrate 20, the heat transfer element 10 is obtained, in which portions of the rod-shaped members that make up the heat transfer portion 30 are fused to the metal fibers of the substrate 20.

[0030] Next, a method for attaching the heat transfer body 10 to the heat transfer object will be described. First, a case where heat is dissipated from a heat transfer object such as a heat-generating electrical or electronic component will be described. To dissipate heat from the heat transfer object, the base material 20 of the heat transfer body 10 is attached to the heat transfer object. If the portion of the heat transfer object to which the base material 20 is to be attached is flat, the base material 20 of the heat transfer body 10 is attached to the heat transfer object by fusion, bolting, screwing, adhesive, or the like. Alternatively, instead of attaching the base material 20 of the heat transfer body 10 to the heat transfer object, the base material 20 of the heat transfer body 10 may simply be placed on the heat transfer object. Even if the portion of the heat transfer object to which the base material 20 is to be attached is not flat but is curved, uneven, or rough, the base material 20 can be deformed to fit the shape of the portion of the heat transfer object to which the base material 20 is to be attached because the base material 20 contains at least metal fibers. This prevents gaps from being formed between the base material 20 and the heat transfer object.

[0031] When attaching the substrate 20 of the heat transfer element 10 to the object to be heated, a heat transfer aid such as thermally conductive grease may be injected into the substrate 20 or between the substrate 20 and the object to be heated. A liquid resin, preferably a liquid thermosetting resin, is used as the heat transfer aid. Alternatively, a liquid rubber containing a thermally conductive filler may be used as the heat transfer aid. Injecting such a heat transfer aid into the substrate 20 or between the substrate 20 and the object to be heated allows for more efficient heat dissipation from the object to be heated. In particular, when the substrate 20 includes a metal fiber nonwoven fabric, the metal fiber nonwoven fabric also serves as a support for the heat transfer aid, allowing the heat transfer aid to be retained in the substrate 20. This prevents the heat transfer aid from leaking out of the substrate 20 or between the substrate 20 and the object to be heated, even if the object to be heated expands or contracts.

[0032] When the base material 20 of the heat transfer body 10 is attached to an object to be heated, even if the object expands or contracts, the base material 20 contains at least metal fibers, which gives the base material 20 flexibility and the ability to conform to the object, thereby preventing gaps from forming between the base material 20 and the object to be heated. This allows sufficient heat transfer to be maintained. Furthermore, because the heat transfer section 30 is partially fused to the metal fibers of the base material 20 but the remaining portion is exposed, the heat transfer body 10 can achieve a sufficient heat transfer effect.

[0033] Next, using FIG. 6 , we will explain the use of the heat transfer device 10 as part of a heat exchanger that removes heat from the surrounding environment by attaching it to the outer periphery of a pipe through which a medium such as cooling water or cooling gas flows. As shown in FIG. 6 , the substrate 20 of the heat transfer device 10 is attached to the outer periphery of the pipe 40, which serves as the heat transfer target, by fusion bonding, bolting, screwing, adhesive, or the like. Since the substrate 20 contains at least metal fibers, it can be bent to fit the curved outer periphery of the pipe, thereby preventing gaps from forming between the substrate 20 and the pipe 40. This allows for sufficient heat transfer. Furthermore, when attaching the substrate 20 of the heat transfer device 10 to the outer periphery of the pipe 40, a heat transfer aid such as the aforementioned thermally conductive grease is injected into the substrate 20 or between the substrate 20 and the pipe 40. This allows for more efficient removal of heat from the surrounding environment for cooling.

[0034] When the base material 20 of the heat transfer body 10 is attached to a pipe 40 to remove heat from the surrounding environment for cooling, even if the pipe 40 expands or contracts, the base material 20 contains at least metal fibers, which gives the base material 20 flexibility and the ability to conform to the object to which heat is being transferred, thereby preventing gaps from forming between the base material 20 and the pipe 40. As a result, sufficient heat transfer performance can be maintained. Even in this case, the heat transfer body 10 can obtain a sufficient heat transfer effect because the heat transfer section 30, which is partially fused to the metal fibers of the base material 20, has the remaining portion exposed.

[0035] 6, the heat exchange unit is configured by combining a substrate 20 containing at least metal fibers, a heat transfer section 30 having a portion fused to the metal fibers of the substrate 20 and the other portion exposed, and an object to which heat is transferred (specifically, a pipe 40) to which the substrate 20 is attached. In such a heat exchange unit, a heat transfer aid is contained between the substrate 20 and the object to which heat is transferred, or in the substrate 20.

[0036] The heat transfer body and the heat exchange unit according to this embodiment are not limited to the above-described embodiments, and various modifications can be made.

[0037] For example, the rod-shaped members of the heat transfer portion are not limited to being arranged at the intersections of the grid lines, and a heat transfer body according to another embodiment may be used in which the rod-shaped members of the heat transfer portion are randomly arranged on the substrate.

[0038] A heat transfer element according to this embodiment may have a configuration as shown in FIG. 7. The heat transfer element 10a shown in FIG. 7 includes a flat substrate 20 to be attached to an object to be heat-transferred and a heat transfer portion 32 composed of multiple plate-like members attached to the substrate 20. The substrate 20 in the heat transfer element 10a shown in FIG. 7 has substantially the same configuration as the substrate 20 in the heat transfer element 10 shown in FIGS. 1 to 6, and therefore its description is omitted. The heat transfer portion 32 has multiple plate-like members extending outward from the substrate 20, and the plate-like members are arranged to extend substantially parallel to each other. Each of these plate-like members is made of, for example, metal. More preferably, the type of metal constituting the metal fibers contained in the substrate 20 is the same as the type of metal constituting each plate-like member of the heat transfer portion 32. In this case, since the substrate 20 and the heat transfer portion 32 are made of the same type of metal, interfacial corrosion between the substrate 20 and the heat transfer portion 32 can be suppressed. However, this embodiment is not limited to this configuration. In another embodiment, the type of metal constituting the metal fibers contained in the substrate 20 and the type of metal constituting each plate-like member of the heat transfer section 32 may be different from each other.

[0039] Furthermore, each plate-like member constituting the heat transfer section 32 has a portion fused to the metal fibers of the substrate 20, and the other portion is exposed. The end of each plate-like member constituting the heat transfer section 32 may extend to a location halfway through the substrate 20 in the thickness direction of the substrate 20. Alternatively, each plate-like member constituting the heat transfer section 32 may penetrate the substrate 20. The length of each plate-like member constituting the heat transfer section 32 is preferably within a range of 1 to 50 mm, and more preferably within a range of 10 to 30 mm. The thickness of each plate-like member constituting the heat transfer section 32 is preferably within a range of 0.1 to 5 mm, and more preferably within a range of 0.5 to 3 mm.

[0040] When the heat transfer body 10a shown in FIG. 7 is used, as in the case of using the heat transfer body 10 shown in FIGS. 1 to 6, the base material 20 to be attached to the object to be heat transferred contains at least metal fibers, which gives the base material 20 flexibility and the ability to conform to the object to be heat transferred. Furthermore, since the heat transfer portion 32, which is partially fused to the metal fibers of the base material 20, has the other portion exposed, a sufficient heat transfer effect can be obtained.

[0041] As yet another example, the heat transfer portion of the heat transfer body may be formed from a member having a shape other than a rod-shaped member or a plate-shaped member. The material of the heat transfer portion is not limited to metal.

[0042] Furthermore, the substrate of the heat transfer body may be made of a material other than a metal fiber nonwoven fabric, as long as it contains at least metal fibers. The shape of the substrate is not limited to a flat plate. [Explanation of symbols]

[0043] 10 Heat Transfer Material 10a Heat transfer body 20 Base material 30 Heat transfer section 32 Heat transfer section 40 Pipe

Claims

1. a substrate made only of metal fibers and to be attached to the object to be heat transferred; a heat transfer portion having a portion fused to the metal fiber of the base material and another portion exposed; Equipped with A heat transfer body, wherein the elongation of the substrate in accordance with JIS P8113 is within a range of 100 ppm to 50,000 ppm.

2. The heat transfer element according to claim 1 , wherein the substrate is flat.

3. The heat transfer body according to claim 1 or 2, wherein the heat transfer portion includes a rod-shaped member extending outward from the base material.

4. The heat transfer body according to claim 3 , wherein a plurality of the rod-shaped members are provided in the heat transfer portion, and each of the rod-shaped members is disposed on an intersection of a grid line.

5. The heat transfer body according to claim 1 or 2, wherein the heat transfer portion includes a plate-like member extending outward from the base material.

6. The heat transfer body according to claim 5 , wherein the heat transfer body includes a plurality of plate-like members, the plate-like members being arranged to extend substantially parallel to one another.

7. The heat transfer body according to claim 1, wherein the elongation of the substrate in accordance with JIS P8113 is in the range of 100 ppm to 20,000 ppm.

8. The heat transfer body according to claim 7, wherein the elongation of the substrate in accordance with JIS P8113 is in the range of 200 ppm to 5,000 ppm.

9. The heat transfer element according to claim 1 , wherein the metal fibers of the substrate are copper fibers or aluminum fibers.

10. The heat transfer element according to claim 1 , wherein the metal fibers of the substrate are nonwoven fabric.

11. The heat transfer element according to claim 1 , wherein the substrate and the heat transfer portion are formed from the same material.

12. A substrate consisting only of metal fibers; a heat transfer portion having a portion fused to the metal fiber of the base material and another portion exposed; a heat transfer object to which the base material is attached; and Equipped with A heat exchange unit, wherein the elongation of the substrate in accordance with JIS P8113 is within a range of 100 ppm to 50,000 ppm.

13. The heat exchange unit according to claim 12 , further comprising a heat transfer aid between the substrate and the object to be heat transferred.

14. A step of preparing a heat transfer body having a substrate made only of metal fibers and having an elongation in the range of 100 ppm to 50,000 ppm according to JIS P8113, and a heat transfer part having a part fused to the metal fibers of the substrate and the other part exposed; a step of attaching the base material of the heat transfer body to an object to be heat transferred; A heat transfer body mounting method comprising:

15. The method for attaching a heat transfer body according to claim 14 , further comprising the step of supplying a heat transfer aid between the base material and the object to be heated in the step of attaching the base material of the heat transfer body to the object to be heated.

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