Method for manufacturing immersion cooling apparatus, heat conductive sheet package, and method for circulating and storing heat conductive sheet

Abstract

The present disclosure addresses the problem of providing a method for manufacturing an immersion cooling apparatus, the method enabling the manufacture of an immersion cooling apparatus having improved cooling performance. A method for manufacturing an immersion cooling apparatus 30 comprises: a first step for preparing a heat conductive sheet 1; a second step for fabricating an electronic device 10 having a circuit board 11, a heat-generating body 12 mounted on the circuit board 11, a heat-dissipating body 13, and a heat conductive sheet 1 disposed between the heat-generating body 12 and the heat-dissipating body 13; and a third step for fabricating the immersion cooling apparatus 30 by immersing at least a part of the electronic device 10 in a cooling medium 20. The method for manufacturing the immersion cooling apparatus 30 includes a step for applying a liquid component 2 to the heat conductive sheet 1 in at least one of the first step and the second step.

Description

Immersion cooling device manufacturing method, thermal conductive sheet package, and thermal conductive sheet distribution and storage method

[0001] The present disclosure relates to a method for manufacturing an immersion cooling device, a thermally conductive sheet package, and a method for distributing and storing a thermally conductive sheet, and more particularly to a method for manufacturing an immersion cooling device using a thermally conductive sheet, a thermally conductive sheet package, and a method for distributing and storing a thermally conductive sheet.

[0002] Patent Document 1 discloses an immersion cooling device used to cool a heat sink, which includes a heat transfer fluid contained in a sealed volume, and in which a thermal interface material is disposed between the heat generating element and the heat sink.

[0003] However, the immersion cooling device of Patent Document 1 uses an indium sheet or the like as a thermal interface material, and there is still room for improvement in terms of cooling performance.

[0004] WO 2006 / 049768

[0005] An object of the present disclosure is to provide a method for manufacturing an immersion cooling device that can manufacture an immersion cooling device with improved cooling performance, a thermally conductive sheet package, and a method for distributing and storing a thermally conductive sheet.

[0006] A method for manufacturing an immersion cooling device according to one aspect of the present disclosure includes a first step of preparing a thermally conductive sheet, a second step of manufacturing an electronic device having a circuit board, a heat generating element mounted on the circuit board, a heat dissipation element, and the thermally conductive sheet disposed between the heat generating element and the heat dissipation element, and a third step of manufacturing an immersion cooling device by immersing at least a portion of the electronic device in a coolant. In the method for manufacturing an immersion cooling device, at least one of the first step and the second step includes a step of applying a liquid component to the thermally conductive sheet.

[0007] A thermally conductive sheet package according to one aspect of the present disclosure includes a thermally conductive sheet, a liquid component, and a container that contains the thermally conductive sheet and the liquid component.

[0008] A method for distributing and storing a thermally conductive sheet according to one aspect of the present disclosure is a method for distributing and storing a thermally conductive sheet, which uses the thermally conductive sheet package.

[0009] 1A, 1B, and 1C are schematic cross-sectional views illustrating steps in a method for manufacturing an immersion cooling device according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing a thermally conductive sheet package according to an embodiment of the present invention.

[0010] 1. Overview Embodiments of the present disclosure will be described with reference to the drawings. Note that the following embodiments are merely examples of various embodiments of the present disclosure. The following embodiments can be modified in various ways depending on the design, etc., as long as they do not deviate from the technical concept of the present disclosure. Furthermore, each figure described in the following embodiments is a schematic diagram, and the ratios of the sizes and thicknesses of the components in each figure do not necessarily reflect the actual dimensional ratios.

[0011] In the conventional immersion cooling apparatus described above, an indium sheet or the like is used as a thermal interface material disposed between the heating element and the heat sink. Because the indium sheet is not compressible, it is unable to sufficiently fill the minute gap between the heating element and the heat sink, which is thought to prevent the cooling performance of the immersion cooling apparatus from being improved. The inventors conducted extensive research to solve the above-mentioned problem and discovered that by setting the thermally conductive sheet disposed between the heating element 12 and the heat sink 13 in the immersion cooling apparatus 30 in a specific state, the cooling performance of the manufactured immersion cooling apparatus 30 can be improved, thereby completing the present disclosure.

[0012] The manufacturing method (X) includes a first step, a second step, and a third step. In the first step, a thermally conductive sheet 1 is prepared. In the second step, an electronic device 10 is fabricated, which includes a circuit board 11, a heat generating element 12 and a heat sink 13 mounted on the circuit board 11, and a thermally conductive sheet 1 disposed between the heat generating element 12 and the heat sink 13. In the third step, at least a portion of the electronic device 10 is immersed in a coolant 20 to fabricate an immersion cooling device 30. In the manufacturing method (X), at least one of the first step and the second step includes a step of applying a liquid component 2 to the thermally conductive sheet 1 (hereinafter also referred to as a "liquid component application step"). "Applying a liquid component to the thermally conductive sheet" means that the liquid component 2 is present on at least a portion of the surface and interior of the thermally conductive sheet 1.

[0013] Manufacturing method (X) allows for the manufacture of an immersion cooling device 30 with improved cooling performance. The reason why manufacturing method (X) provides the above-described effect by incorporating the above configuration can be inferred, for example, as follows. Even if the thermally conductive sheet is porous or has grooves or holes, even if the thermally conductive sheet is impregnated with a liquid component after assembly of the electronic device, the liquid component cannot adhere to the surface of the thermally conductive sheet or penetrate into gaps or voids because the thermally conductive sheet is sandwiched between the heat-generating element and the heat-dissipating element. As a result, air remains in the gaps and voids in the thermally conductive sheet, increasing thermal resistance. By performing a liquid component application step in at least one of the first step of preparing the thermally conductive sheet 1 and the second step of fabricating the electronic device 10 using the thermally conductive sheet 1, the liquid component 2 can be present on at least a portion of the surface and interior of the thermally conductive sheet 1, as shown in FIG. 1A . This allows the liquid component 2 present on the surface of the thermally conductive sheet 1 to fill tiny gaps between the thermally conductive sheet 1 and the heating element 12, and between the thermally conductive sheet 1 and the heat sink 13, thereby reducing the thermal resistance between the heating element 12 and the heat sink 13. Furthermore, the liquid component 2 present inside the thermally conductive sheet 1 can fill voids and the like, thereby reducing the thermal resistance of the thermally conductive sheet 1. These factors are believed to improve the cooling performance of the immersion cooling device 30 produced. Furthermore, manufacturing method (X) also has the effect of temporarily fixing the thermally conductive sheet 1 by utilizing the viscosity of the liquid component 2.

[0014] The thermally conductive sheet package 100 of this embodiment includes a thermally conductive sheet 1, a liquid component 2, and a container 50 that accommodates the thermally conductive sheet 1 and the liquid component 2.

[0015] According to the thermal conductive sheet package 100, the thermal conductive sheet 1 is present in the liquid component 2, and the liquid component 2 is applied to the thermal conductive sheet 1, so that a thermal conductive sheet 1 that can be suitably used in the manufacturing method (X) can be easily and reliably provided.

[0016] The method for distributing and storing a thermally conductive sheet according to this embodiment is a method for distributing and storing a thermally conductive sheet 1, and uses a thermally conductive sheet package 100. According to this method for distributing and storing a thermally conductive sheet 1, by using a thermally conductive sheet package 100 in which the thermally conductive sheet 1 is present in a liquid component 2 and the liquid component 2 is applied to the thermally conductive sheet 1, the thermally conductive sheet 1 can be stably stored while being maintained in a state suitable for use in the manufacturing method (X).

[0017] As described above, according to the manufacturing method (X) for the immersion cooling apparatus 30 of the present disclosure, it is possible to manufacture an immersion cooling apparatus 30 with improved cooling performance. According to the thermal conduction sheet package 100 of the present disclosure, it is possible to easily and reliably provide a thermal conduction sheet 1 that can be suitably used in the manufacturing method (X) for the immersion cooling apparatus 30. According to the method for distributing and storing the thermal conduction sheet 1 of the present disclosure, it is possible to stably store the thermal conduction sheet 1 while maintaining it in a state that allows it to be suitably used in the manufacturing method (X) for the immersion cooling apparatus 30.

[0018] 2. Details <Method for Manufacturing Immersion Cooling Apparatus> Hereinafter, the method (X) for manufacturing the immersion cooling apparatus 30 of this embodiment will be described in detail.

[0019] Manufacturing method (X) includes a first step of preparing thermally conductive sheet 1, a second step of fabricating electronic device 10, and a third step of fabricating immersion cooling apparatus 30. In manufacturing method (X), at least one of the first step and the second step includes a liquid component application step. Each step will be described below.

[0020] [First Step] In the first step, a thermally conductive sheet 1 is prepared. (Thermal Conduction Sheet) The thermally conductive sheet 1 is a member for transferring heat from the heat generating element 12 to the heat dissipating element 13 in the immersion cooling apparatus 30. The thermally conductive sheet 1 is not particularly limited, and various materials can be used.

[0021] The average thickness of the thermal conductive sheet 1 is, for example, 30 μm to 500 μm, and preferably 50 μm to 200 μm. The "average thickness" refers to the arithmetic mean value of thicknesses measured at multiple points (e.g., any 10 points) on the thermal conductive sheet 1.

[0022] The shape of the thermally conductive sheet 1 is preferably at least one selected from irregularities, slits, grooves, and holes, or at least one selected from spongy, fibrous, and laminated shapes. "Having irregularities" includes not only cases where both concave and convex portions are present, but also cases where only concave portions or only convex portions are present. A slit refers to a narrow cut or notch that penetrates the thermally conductive sheet. A groove refers to a linear or curved opening that does not penetrate the thermally conductive sheet. A hole includes both a gap that does not penetrate the thermally conductive sheet and a through-hole that penetrates the sheet. A spongy shape refers to a shape with numerous internal holes, which may be interconnected or closed. A honeycomb shape refers to a shape consisting of multiple linear holes separated by thin partitions, and the cross section of the linear holes may be hexagonal or other shapes. "Fibrous" means that each material constituting the thermally conductive sheet has a fibrous shape (e.g., a length-to-diameter ratio of 3 or more). A laminated shape refers to a shape in which layered structures are stacked. Because the thermal conduction sheet 1 has this shape, it can be easily crushed by compression, filling the gap between the heat generating element 12 and the heat dissipating element 13, further reducing the thermal resistance, and thereby further improving the cooling performance of the immersion cooling device 30.

[0023] Furthermore, it is preferable that at least a portion of the thermally conductive sheet 1 be made of a porous material. In this case, the liquid component 2 can easily penetrate into the thermally conductive sheet 1, thereby further improving the cooling performance of the immersion cooling apparatus 30. The term "porous material" refers to a solid having pores (voids) therein. The term "voids" refers to portions where the material constituting the thermally conductive sheet 1 is absent. The pores in the porous material may be interconnected or isolated, and may or may not be connected to the surface of the thermally conductive sheet 1. However, interconnected pores connected to the surface are preferred. In this case, the liquid component 2 can easily penetrate and penetrate into the voids in the thermally conductive sheet 1. When the thermally conductive sheet 1 is made of a porous material, the porosity of the thermally conductive sheet 1 is preferably 30% by volume or more and 95% by volume or less, and more preferably 50% by volume or more and 90% by volume or less. The "porosity" (volume %) is a value calculated by [1 - (apparent specific gravity of thermally conductive sheet / true specific gravity of material constituting the thermally conductive sheet)] x 100. The apparent specific gravity of the thermally conductive sheet can be calculated from the volume and mass determined from the external dimensions of the thermally conductive sheet. In this case, the thermally conductive sheet 1 is preferably composed of a porous material in an amount of 50 mass % or more, more preferably 90 mass % or more, and may be composed of a porous material in an amount of 100 mass %.

[0024] It is preferable that thermally conductive sheet 1 does not react with liquid component 2 and does not dissolve in liquid component 2. By using such a thermally conductive sheet 1, the cooling performance of immersion cooling apparatus 30 can be maintained.

[0025] The compression ratio of the thermally conductive sheet 1 when compressed in the thickness direction at 200 kPa is preferably 5% or more and 95% or less. In this case, the gap between the thermally conductive sheet 1 and the heating element 12 and the heat sink 13 can be more effectively filled, thereby further reducing thermal resistance. The compression ratio of the thermally conductive sheet 1 is more preferably 20% or more and 95% or less, and even more preferably 30% or more and 95% or less. The "compression ratio" of the thermally conductive sheet 1 is the value of 1-T1 / T0 expressed as a percentage, where T0 is the initial thickness of the thermally conductive sheet 1 and T1 is the thickness after applying a pressure of 200 kPa.

[0026] The thermal conductive sheet 1 is preferably made of graphite. "Graphite" refers to graphite, a type of carbon allotrope, and is also called graphite. Graphite is a material in which carbon atoms are sp ２ The graphite has a structure in which multiple layers (graphene layers) arranged in a hexagonal honeycomb lattice pattern are bonded together in the thickness direction by van der Waals forces and stacked together. Examples of graphite include a stack of multiple graphite layers.

[0027] 1B , an electronic device 10 is fabricated that includes a circuit board 11, a heat generating element 12 mounted on the circuit board, a heat sink 13, and a thermally conductive sheet 1 disposed between the heat generating element 12 and the heat sink 13. Specifically, the second step is typically performed by arranging the heat generating element 12, the thermally conductive sheet 1, and the heat sink 13 in this order in addition to the circuit board 11, that is, by sandwiching the thermally conductive sheet between the heat generating element 12 and the heat sink 13, and then compressing them.

[0028] (Circuit Board) The circuit board 11 is a board including circuits such as an inverter circuit and a motor drive circuit for operating the electronic device 10. The electronic device 10 may have one or more circuit boards. The circuit board 11 may be a single-layer board or a multi-layer board.

[0029] (Heater) The heater 12 is a heat-generating component mounted on the circuit board 11. The heater 12 is, for example, a semiconductor component. Examples of semiconductor components include, but are not limited to, transistors, CPUs (central processing units), MPUs (microprocessing units), driver ICs, and memories. The heater 12 may be, for example, composed of a heat spreader and a chip portion fixed on the heat spreader. The heat spreader is a plate-shaped component made of metal or the like, and the chip portion is, for example, a semiconductor package. In this case, the chip portion is disposed on a portion of the heat spreader excluding the outer edge portion, and a plurality of screw holes or the like may be formed in the outer edge portion at positions corresponding to a plurality of screw holes or the like penetrating the heat spreader.

[0030] (Heat Dissipator) The heat dissipator 13 is a member to which heat generated by the heat generating element 12 is transferred. Heat can be dissipated from the heat dissipator 13. The heat dissipator 13 is, for example, a heat sink. When the heat dissipator 13 is a plate-shaped heat sink, the heat dissipator 13 may further include heat dissipation fins. The heat dissipator 13 may have a plurality of screw holes or the like formed at positions corresponding to the plurality of screw holes or the like in the heat generating element 12 described above.

[0031] [Electronic Device] Electronic device 10 is fabricated by arranging circuit board 11, heat generating element 12, thermally conductive sheet 1, and heat dissipation element 13 in this order. Immersion cooling apparatus 30 may include one or more electronic devices 10.

[0032] Examples of electronic devices 10 include HDDs, DVD players, mobile phones, smartphones, tablet terminals, automotive electronic control units (ECUs), power control units (PCUs), display devices such as liquid crystal displays, organic EL lighting, solar cells, touch panels, camera modules, inverters, converters, etc., as well as blade servers that incorporate these devices, memory, CPUs (central processing units), and other components in a small housing.

[0033] [Third Step] In the third step, as shown in FIG. 1C, at least a portion of the electronic device 10 produced in the second step is immersed in a coolant 20 to produce an immersion cooling device 30.

[0034] (Coolant) The coolant 20 is a medium used to cool the electronic device 10, particularly the heat sink 13. The coolant 20 is usually placed in a container or the like.

[0035] Any insulating liquid with high electrical insulation properties can be used as the coolant 20. Examples of insulating liquids include hydrocarbon oils such as hydrocarbons and polyalphaolefins (PAOs); fluorine-containing oils such as perfluorocarbons, hydrofluorocarbons, hydrofluoroethers, and perfluoroketones; silicone oils; hydrocarbon compounds such as alkylbenzenes, alkylnaphthalenes, and alkyldiphenylalkanes; and mineral oils such as mineral oil.

[0036] Immersion cooling apparatus 30 is fabricated by immersing at least a portion of electronic device 10 in coolant 20. The immersion cooling apparatus 30 is preferably configured such that the entire electronic device 10 is immersed in coolant 20. Immersion cooling apparatus 30 may further include a heat exchanger that exchanges heat between coolant 20 supplied by a pump (not shown) and cooling water supplied from a cooling unit (not shown), thereby controlling the temperature of coolant 20.

[0037] [Liquid Component Application Step] In production method (X), at least one of step 1 and step 2 includes a liquid component application step. That is, in production method (X), as shown in Fig. 1A , liquid component 2 is applied to thermally conductive sheet 1 in step 1 and / or step 2. This allows liquid component 2 to be present on the surface and / or inside thermally conductive sheet 1, and as a result, the cooling performance of immersion cooling apparatus 30 can be improved.

[0038] (Liquid Component) The liquid component 2 is a liquid that is applied to the thermally conductive sheet 1 to impregnate it in the production method (X).

[0039] Any insulating liquid having high electrical insulation properties can be used as the liquid component 2. Examples of insulating liquids include the same substances as those exemplified as the coolant 20 described above.

[0040] It is preferable that liquid component 2 and the components constituting coolant 20 are of the same type. In this case, the cooling performance of immersion cooling device 30 can be maintained even if liquid component 2 impregnated in thermally conductive sheet 1 is replaced with coolant 20. "Of the same type" means that both liquid component 2 and coolant 20 are included in the same type of insulating liquid (hydrocarbon oil, fluorine-containing oil, silicone oil, hydrocarbon compound, mineral oil).

[0041] As a result of the liquid component application step, it is preferable that the liquid component 2 is present on at least a portion of the surface and inside of the thermal conductive sheet 1, and it is more preferable that the liquid component 2 is present throughout the surface and inside of the thermal conductive sheet 1. In other words, it is preferable that the liquid component 2 is contained in at least a portion of the thermal conductive sheet 1 as a result of the liquid component application step, and it is more preferable that the liquid component 2 is contained throughout the entire thermal conductive sheet 1.

[0042] The manufacturing method (X) preferably includes a liquid component application step in the first step. When the liquid component application step is performed in the first step, when the thermally conductive sheet 1 to which the liquid component 2 has been applied is incorporated into the electronic device 10 in the second step, the thermally conductive sheet 1 is sandwiched and compressed between the heat generating element 12 and the heat dissipating element 13, making it difficult for air to enter between the thermally conductive sheet 1 and the heat generating element 12 and the heat dissipating element 13. Furthermore, when the thermally conductive sheet 1 is sandwiched and compressed, any remaining air is expelled along with the excess liquid component. Examples of methods for performing the liquid component application step in the first step include immersing the thermally conductive sheet 1 in the liquid component 2 contained in a container, applying the liquid component 2 to the thermally conductive sheet 1, and impregnating the thermally conductive sheet 1 with the liquid component 2. These methods may also be performed by vacuum impregnation. If the thermally conductive sheet 1 is porous or has voids such as pores, the liquid component 2 preferably penetrates into the voids in the thermally conductive sheet 1.

[0043] It is also preferable that the manufacturing method (X) includes a liquid component application step in the second step. Examples of methods for performing the liquid component application step in the second step include immersing the electronic device 10 produced or being produced in the second step in the liquid component 2 contained in a container, or impregnating the thermally conductive sheet 1 of the electronic device 10 with the liquid component 2. These methods may also be performed by vacuum impregnation. It is necessary that the liquid component application step in the second step be performed before the thermally conductive sheet 1 is sandwiched between the heating element 12 and the heat sink 13 and compressed.

[0044] The production method (X) may include a liquid component application step in both the first step and the second step.

[0045] <Thermal Conductive Sheet Package> Fig. 2 is a cross-sectional view showing the thermal conductive sheet package 100. The thermal conductive sheet package 100 includes a thermal conductive sheet 1, a liquid component 2, and a container 50 that contains the thermal conductive sheet 1 and the liquid component 2.

[0046] The thermally conductive sheet package 100 may include one or more thermally conductive sheets 1. When the thermally conductive sheet package 100 includes multiple thermally conductive sheets 1, a separator film may be disposed between each of the multiple thermally conductive sheets 1. In this case, the multiple thermally conductive sheets 1 can be prevented from contacting each other, making it easier to remove the multiple thermally conductive sheets 1.

[0047] The shape of the container 50 of the thermally conductive sheet package 100 is preferably a shallow body with the top surface sealed, as shown in Fig. 2. By adopting such a shape, the thermally conductive sheet 1 can be more easily removed from the thermally conductive sheet package 100 in the manufacturing method (X).

[0048] In the thermally conductive sheet package 100, at least a portion of the thermally conductive sheet 1 is preferably impregnated with the liquid component 2. It is more preferable that the entire thermally conductive sheet 1 is impregnated with the liquid component 2. In this case, the cooling performance of the immersion cooling apparatus 30 to be manufactured can be further improved.

[0049] In the thermally conductive sheet package 100, the volume of the liquid component 2 is preferably larger than the volume of the thermally conductive sheet 1. In this case, the cooling performance of the immersion cooling apparatus 30 to be manufactured can be further improved.

[0050] In thermally conductive sheet package 100, thermally conductive sheet 1 is preferably made of graphite. In this case, the cooling performance of the immersion cooling apparatus 30 to be manufactured can be further improved.

[0051] <Method for Distributing and Preserving Thermally Conductive Sheet> The method for distributing and preserving a thermally conductive sheet according to this embodiment is a method for distributing and preserving a thermally conductive sheet 1, and is a method using the thermally conductive sheet package 100 described above.

[0052] By distributing the thermally conductive sheet 1 together with the liquid component 2 in a container 50 as a thermally conductive sheet package 100, the thermally conductive sheet 1 is present in the liquid component 2, and the state in which the liquid component 2 is applied to the thermally conductive sheet 1 or the liquid component 2 is impregnated into the thermally conductive sheet 1 is maintained, allowing for stable storage. The thermally conductive sheet 1 removed from this thermally conductive sheet package 100 is in a state in which the liquid component 2 is impregnated into the thermally conductive sheet 1, and therefore can be suitably used as is in the above-mentioned manufacturing method (X).

[0053] (Summary) As is clear from the above embodiment, the present disclosure includes the following aspects. In the following, reference numerals are given in parentheses only to clarify the correspondence with the embodiment.

[0054] The method for manufacturing an immersion cooling device (30) of the first aspect includes a first step of preparing a thermally conductive sheet (1), a second step of manufacturing an electronic device (10) having a circuit board (11), a heat generating element (12) mounted on the circuit board (11), a heat dissipating element (13), and a thermally conductive sheet (1) disposed between the heat generating element (12) and the heat dissipating element (13), and a third step of immersing at least a portion of the electronic device (10) in a cooling medium (20) to manufacture the immersion cooling device (30). The method for manufacturing the immersion cooling device (30) includes a step of applying a liquid component (2) to the thermally conductive sheet (1) in at least one of the first step and the second step.

[0055] According to the first aspect, it is possible to reduce the thermal resistance between the heat generating element (12) and the heat dissipating element (13) and / or the thermal conduction sheet (1), and to manufacture an immersion cooling device (30) with improved cooling performance.

[0056] In the method for producing the immersion cooling apparatus (30) of the second embodiment, the liquid component (2) and the component constituting the cooling medium (20) in the first embodiment are the same type.

[0057] According to the second aspect, even if the liquid component (2) impregnated in the thermally conductive sheet (1) is replaced with the cooling medium (20), the cooling performance of the immersion cooling device (30) can be maintained.

[0058] In the method for manufacturing an immersion cooling device (30) of the third aspect, in the first or second aspect, the heat conductive sheet (1) is made of graphite.

[0059] According to the third aspect, the cooling performance of the immersion cooling apparatus (30) can be further improved.

[0060] The thermally conductive sheet package (100) of the fourth embodiment comprises a thermally conductive sheet (1), a liquid component (2), and a container (50) for containing the thermally conductive sheet (1) and the liquid component (2).

[0061] According to the fourth aspect, it is possible to easily and reliably provide a heat conductive sheet (1) that can be suitably used in a manufacturing method for an immersion cooling device (30).

[0062] In the thermally conductive sheet package (100) of the fifth embodiment, the volume of the liquid component (2) is larger than the volume of the thermally conductive sheet (1) in the fourth embodiment.

[0063] According to the fifth aspect, the cooling performance of the immersion cooling device (30) manufactured using the thermally conductive sheet package (100) can be further improved.

[0064] In the heat conductive sheet package (100) of the sixth aspect, in the fourth or fifth aspect, at least a part of the heat conductive sheet (1) is impregnated with the liquid component (2).

[0065] According to the sixth aspect, the cooling performance of the immersion cooling device (30) manufactured using the thermally conductive sheet package (100) can be further improved.

[0066] In the seventh aspect of the thermally conductive sheet package (100), in any one of the fourth to sixth aspects, the thermally conductive sheet (1) is made of graphite.

[0067] According to the seventh aspect, the cooling performance of the immersion cooling device (30) manufactured using the thermally conductive sheet package (100) can be further improved.

[0068] The method for distributing and storing a thermally conductive sheet (1) according to an eighth aspect is a method for distributing and storing a thermally conductive sheet (1). The method for distributing and storing a thermally conductive sheet (1) uses a thermally conductive sheet package (100) according to any one of the fourth to seventh aspects.

[0069] According to the eighth aspect, the thermally conductive sheet (1) can be stably stored while maintaining a state suitable for use in the manufacturing method of the immersion cooling device (30).

[0070] REFERENCE SIGNS LIST 1 Thermally conductive sheet 2 Liquid component 10 Electronic device 11 Circuit board 12 Heat generating element 13 Heat dissipation element 20 Cooling medium 30 Immersion cooling device 50 Container 100 Thermally conductive sheet package

Claims

1. A method for manufacturing an immersion cooling device comprising: a first step of preparing a thermally conductive sheet; a second step of fabricating an electronic device having a circuit board, a heat generating element mounted on the circuit board, a heat sink, and the thermally conductive sheet disposed between the heat generating element and the heat sink; and a third step of fabricating an immersion cooling device by immersing at least a portion of the electronic device in a cooling medium, wherein at least one of the first step and the second step includes a step of applying a liquid component to the thermally conductive sheet.

2. The method for manufacturing an immersion cooling device according to claim 1, wherein the liquid component and the component constituting the cooling medium are of the same type.

3. The method for manufacturing an immersion cooling device according to claim 1, wherein the thermally conductive sheet is made of graphite.

4. A thermally conductive sheet package comprising a thermally conductive sheet, a liquid component, and a container for containing the thermally conductive sheet and the liquid component.

5. The thermal conductive sheet package according to claim 4, wherein the volume of the liquid component is greater than the volume of the thermal conductive sheet.

6. The thermal conductive sheet package according to claim 4, wherein at least a portion of the thermal conductive sheet is impregnated with the liquid component.

7. The thermal conductive sheet package according to claim 4, wherein the thermal conductive sheet is made of graphite.

8. A method for distributing and storing a thermally conductive sheet, comprising using the thermally conductive sheet package according to any one of claims 4 to 7.

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