Thermal management panel

Abstract

To provide a thermal management panel that efficiently cools heat-generating elements without enlarging the cooling system, thereby maintaining the heat-generating elements at an appropriate temperature.SOLUTION: A cooling panel 30 comprises a metal tube wrapped in molten metal, with a refrigerant flow path 50 inside a main panel body 40. Both the refrigerant flow path 50 and the main panel body 40 are formed to align with the positions of the elements 11, 12, 14 so that they can be closely fitted to a plurality of elements 11, 12, 14 of differing heights.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a thermal management panel that dissipates heat from electronic devices and circuit boards that mount heat-generating electronic components and equipment, and in particular to a thermal management panel in which pipes that form refrigerant flow paths are manufactured by insert molding. [Background technology]

[0002] Conventionally, circuit boards such as inverters are equipped with many heat-generating elements. In order for such circuit boards to achieve the required performance and durability, they must be kept below an allowable temperature. If the temperature of the elements mounted on the circuit board rises above the allowable temperature, not only will the performance of the elements deteriorate, but excessive thermal stress will be applied to the solder joints connecting the elements to the circuit board, causing breakage.

[0003] For electrolytic capacitors, there is a definition of the 10°C doubling rule, which states that if the temperature drops by 10°C, the lifespan will double, and conversely, if the temperature rises by 10°C, the lifespan will tend to be reduced to half. From the perspective of circuit board design, the countermeasures up until now have required the selection of appropriate components to reduce loss and circuit board patterning (element placement and wiring) that takes heat generation into consideration.

[0004] Furthermore, as an active heat dissipation method, a water-cooled panel or an air-cooled heat sink has been used in close contact with the heat-generating elements on the back or front of the circuit board. Of these, the most effective is the water-cooled panel. The water-cooled panel structure includes a method in which a flow path is provided inside a box-shaped panel, and a panel made by encasing curved metal cooling pipes in molten metal (see, for example, Patent Document 1). In all of these, the cooling surface is flat. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Utility Model Application Publication No. 51-80322 [Patent Document 2] Patent No. 4829552 Summary of the Invention [Problem to be solved by the invention]

[0006] The above cooling methods have the following drawbacks: (1) Because many heat-generating elements of different sizes and shapes are mounted on the mounting surface of a circuit board, a water-cooled panel is usually attached only to the back surface of the circuit board, which does not have any protrusions. However, cooling large heat-generating elements from the back surface through the circuit board is inefficient.

[0007] (2) On the other hand, to cool components from the front side of a circuit board, a water-cooled panel is placed in close contact with the tallest component, and a thermally conductive filler (gap filler) is placed in the gap between the tallest component and the water-cooled panel to ensure a heat transfer path for the remaining components. However, because the thermal conductivity of thermally conductive filler is approximately 2–5 W / mK, if the gap is larger than a few millimeters, the thermal resistance increases and the cooling performance of the component is significantly reduced. Furthermore, using a large amount of thermally conductive filler increases the weight of the electronic device, which is undesirable for applications such as electric vehicle inverters. However, because the thermal conductivity of thermally conductive filler is approximately 100 times that of air (0.025 W / mK), thermally conductive filler is currently used in the gap.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a thermal management panel that can efficiently cool heat-generating elements without enlarging the cooling system, and can maintain the heat-generating elements at an appropriate temperature. [Means for solving the problem]

[0009] The present invention is a thermal management panel having a refrigerant flow path inside the panel body, in which a metal tube is wrapped in molten metal, and both the refrigerant flow path and the panel body are molded to match the shape and / or position of the heat source so that it can be closely fitted to a heat source with a three-dimensional shape and / or multiple heat sources of different heights.

[0010] According to the present invention, both the refrigerant flow path and the panel body are molded to match the shape and / or position of the heat source, so the refrigerant flow path is close to the heat source. This allows the refrigerant to efficiently cool the heat source and maintain it at an appropriate temperature. Furthermore, because the panel body is molded to match the shape and position of the heat source, the volume of the panel body can be kept to a minimum, making the cooling system smaller and lighter.

[0011] In the present invention, the coolant flow path can be located, for example, approximately at the center of the panel body in the thickness direction, which allows the thickness of the panel body to be minimized to be slightly thicker than the coolant flow path, maximizing heat absorption from the heat source and heat dissipation from the panel body.

[0012] The refrigerant flow path in the present invention is formed as a three-dimensional cooling pipe by bending a single metal pipe into a predetermined shape. For example, the ends of the pipe can be aligned, formed to extend in a spiral shape from both ends, and then the spiral pipe formed on a single plane can be bent to create a three-dimensional cooling pipe. The refrigerant flow path is formed by a technique called "insertion casting," in which such cooling pipe is wrapped in the molten metal of the panel body.

[0013] Alternatively, the refrigerant flow path can be formed in a serpentine shape with multiple vertical flow paths extending in the planar direction of the panel body and horizontal flow paths connecting the ends of the vertical flow paths, and by tilting at least a portion of the horizontal flow paths with respect to the plane of the panel body, a three-dimensional refrigerant flow path can be formed.

[0014] In this case, a serpentine-shaped cooling pipe can be fabricated by fitting and connecting the ends of the U-shaped pipes together. In this embodiment, if one U-shaped pipe is twisted relative to the other U-shaped pipe when fitting the ends of the U-shaped pipes together, the one U-shaped pipe will become a three-dimensional cooling pipe that protrudes from the plane formed by the other U-shaped pipe.

[0015] It is desirable to place a thermally conductive sheet or thermally conductive filler between the heat source. Since many of the elements mounted on the circuit board have uneven surfaces, it is necessary to fill the gap between the heat management panel and the thermally conductive sheet or thermally conductive filler. A carbon sheet (expanded graphite sheet) is suitable as a thermally conductive sheet. A carbon sheet is made by molding expanded graphite into a sheet, and is flexible and cushiony, so it adheres to the contact surface and has the effect of reducing contact thermal resistance. It can be used up to 400°C in air and 1000°C in a vacuum. Thicknesses range from 0.2mm to several mm.

[0016] According to Patent Document 2, the thermal conductivity in the thickness direction is about 5 W / mK, the thermal conductivity in the surface direction is about 200 W / mK, and the applied pressure is 0.1 MPa (1 kg / cm 2 ) the contact thermal resistance is approximately 1×10 when the thickness is 0.2 mm. -4 (m2K / W). By using a carbon sheet, the contact thermal resistance can be reduced to, for example, 1 / 10 or less compared to when it is not used. The contact thermal resistance of a carbon sheet depends on the pressure applied, and a pressure of 0.1 MPa (1 kg / cm) is required to achieve a specified reduction in contact thermal resistance. 2 In the present invention, in order to obtain such a pressure, an elastic member such as urethane or rubber can be interposed between the upper cover of the casing that houses the circuit board and the heat management panel.

[0017] The thermally conductive sheet is not limited to the carbon sheet described above; any sheet with high thermal conductivity in the thickness direction and low contact thermal resistance would be more suitable. For example, a carbon fiber thermally conductive sheet in which carbon fibers are oriented in the thickness direction of the sheet can be used. Alternatively, a thermally conductive sheet in which oval-shaped boron nitride fillers are blended vertically in the thickness direction of the sheet can also be used.

[0018] Thermally conductive fillers are commercially available under names such as gap filler, and have a thermal conductivity of approximately 2 to 5 W / mK. Thermally conductive fillers are paste-like and flexible, allowing them to fill gaps. While thermal conductivity is not high, they are effective in reducing contact thermal resistance if the gap being filled is less than a few millimeters. Specifically, heat-dissipating silicone can be used. Heat-dissipating silicones include paste-like, non-hardening thermal grease and paste-like, hardening, but flexible heat-dissipating gap fillers. Silicon-free heat-dissipating greases based on hydrocarbon synthetic oils such as ester oil and polyalphaolefin can also be used.

[0019] Heat source elements mounted on a circuit board may have various heights from the circuit board. The thermal management panel of the present invention can be closely attached to both the tallest and shortest elements. Furthermore, elements mounted on a circuit board may be elongated, such as capacitors. The thermal management panel of the present invention can be closely attached to the side and top surfaces of the capacitor, allowing the capacitor to be cooled efficiently.

[0020] In the present invention, the metal pipes can be made of the same material as the molten metal. For example, aluminum can be used as the material. It is also possible to make the metal cooling pipes out of stainless steel, for example, and the panel body out of aluminum. However, since the thermal conductivity of stainless steel is significantly lower than that of aluminum, it is preferable to make the cooling pipes out of aluminum as well. In this case, casting is performed by placing the aluminum cooling pipes in the mold and injecting the molten aluminum into the mold while the cooling water is held or flowing in the cooling pipes. [Effects of the Invention]

[0021] According to the present invention, both the refrigerant flow path and the panel body are molded to match the shape and / or position of the heat source, so the refrigerant flow path is close to the heat source, allowing the heat source to be efficiently cooled by the refrigerant and maintained at an appropriate temperature without increasing the size of the cooling system. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a side view showing a state in which a thermal management panel according to a first embodiment of the present invention is attached to a circuit board. [Figure 2] 1 is a plan view showing a state in which a thermal management panel according to a first embodiment is attached to a circuit board. [Figure 3] 1 is a cross-sectional view showing a thermal management panel of a first embodiment. [Figure 4] FIG. 10 is a plan view showing a U-shaped pipe that is a component of the cooling piping in a modified example of the first embodiment. [Figure 5] FIG. 6 is a plan view showing a cooling pipe to which the U-shaped pipes shown in FIG. 5 are connected. [Figure 6] FIG. 10 is a side view showing a state in which a thermal management panel according to a second embodiment of the present invention is attached to a circuit board. DETAILED DESCRIPTION OF THE INVENTION

[0023] 1. First embodiment (1) Thermal management panel configuration A first embodiment of the present invention will be described with reference to FIGS. In Fig. 1, reference numeral 10 denotes a circuit board. Elements (heat sources) 11, 12, and 14 are mounted on the circuit board 10. The element 11 is tall from the circuit board 10, while the elements 12 and 14 are shorter than the element 11, with the same height from the circuit board 10. A heat management panel (hereinafter abbreviated as "cooling panel") 30 is attached to the elements 11, 12, and 14 via thermally conductive sheets 21 and 22.

[0024] The cooling panel 30 is constructed by molding a refrigerant flow path 50 inside a panel body 40 that is cast from metal. The panel body 40 has a substantially square shape in a plan view, and a step 41 that is one step lower is formed on one side of the panel body 40. As a result, the step 41 is in close contact with the short elements 12, 14 via the thermally conductive sheet 22, and the portion other than the step 41 is in close contact with the tall element 11 via the thermally conductive sheet 21. The refrigerant flow path 50 is located approximately in the center of the panel body 40 in the thickness direction.

[0025] 2, the refrigerant flow path 50 has a serpentine shape that moves back and forth in a zigzag pattern, and includes multiple vertical flow paths 51 that extend in parallel to one another and semicircular arc-shaped horizontal flow paths 52 that connect the ends of the vertical flow paths. Such a refrigerant flow path 50 is formed by insert-casting a cooling piping that is formed by bending a single pipe.

[0026] An inlet 53 and an outlet 54 are provided at the ends of the vertical flow paths 51 on both ends. A coolant such as water is supplied to the inlet 53 from a pump (not shown), passes through the coolant flow path 50, and is discharged from the outlet 54. The panel body 40 is cooled by the coolant, and heat generated by the elements 11, 12, and 14 is absorbed by the panel body 40 via the thermally conductive sheets 21 and 22. Although not shown, an elastic member such as rubber or urethane is interposed between the cooling panel 30 and the top cover of the casing that houses the circuit board 10, and this applies a pressure of about 0.1 MPa to the thermally conductive sheets 21 and 22.

[0027] The cooling panel 30 having the above configuration is formed by insert casting. Specifically, a cooling pipe formed by bending a single pipe into a serpentine shape as shown in Figure 2 is set in a mold, the mold is closed, and molten metal is poured into the mold through a gate. In this way, the cooling panel 30 having the refrigerant flow path 50 shown in Figure 3 is formed.

[0028] Here, it is desirable that the metal constituting the panel body 40 has high thermal conductivity, is lightweight, and has a linear expansion coefficient close to that of the cooling piping. Copper and aluminum are suitable for high thermal conductivity. However, the material is not limited to these, and other materials may also be used. From the perspective of weight reduction, aluminum is optimal. When aluminum is selected as the metal constituting the panel body 40 and the material for the cooling piping, the cooling piping is cast while water is retained or flowing through it.

[0029] There are no particular restrictions on the dimensions of the cooling panel 30, but from a manufacturability perspective, it is easy to produce planar dimensions of several centimeters to several tens of centimeters square. Planar shapes such as square, rectangular, and circular can be used to suit the heat source to be used. The cooling panel 30 has a step 41 so that it can be fitted closely to multiple heat sources of different heights. Since flatness and parallelism with the heat source are important for the panel surface that comes into close contact with the heat source, machining such as cutting and polishing is performed after casting as necessary. From the perspective of heat transfer performance, it is desirable for the thickness of the panel body 40, which is located between the heat source elements 11, 12, and 14 and the tube, to be thin.

[0030] Materials for the pipes include, but are not limited to, aluminum, copper, and stainless steel. Metals that are compatible with the coolant and suitable for bending (plastic processing) are preferred. From the perspective of the heat transfer performance of the cooling panel 30, the longer the overall length of the cooling piping 60 inside the cooling panel 30, the better. Therefore, the cooling piping is bent inside the cooling panel 30 with as little curvature as possible. The melting point of the cooling piping used is generally higher than the melting point of the metal being cast, but it is also possible to use the same material.

[0031] For example, a combination of aluminum cooling pipes and an aluminum panel body 40 has the advantage of achieving both heat transfer performance and weight reduction. In such a case, melting of the aluminum cooling pipes can be avoided by first holding or flowing water or the like in the aluminum cooling pipes before pouring the molten aluminum into the mold.

[0032] The diameter and thickness of the cooling pipes are determined taking into consideration the possible bending radius. The cooling pipes, excluding the sections connected to the inlet 53 and outlet 54, must be cast into the cooling panel 30, so they are bent three-dimensionally to fit the step 41 of the cooling panel 30. From the perspective of heat transfer performance, it is desirable that the thickness of the panel body 40 interposed between the heat source and the cooling pipes is thin. Therefore, it is desirable that the three-dimensional routing of the cooling pipes be assembled with high precision so that they fit the step 41 of the cooling panel 30.

[0033] (2) Effects In the cooling panel 30 of the first embodiment, a refrigerant such as water is injected through the inlet 53, passes through the serpentine-shaped refrigerant flow path 50, and is discharged from the outlet 54. During this time, heat generated by the elements 11, 12, and 14 is absorbed by the panel body 40, and the heat absorbed by the panel body 40 is dissipated into the refrigerant.

[0034] In the cooling panel 30, both the refrigerant flow path 50 and the panel body 40 are molded to fit the positions of the elements 11, 12, and 14 so that they can be in close contact with the elements 11, 12, and 14, which are of different heights. This means that the refrigerant flow path 50 is close to the elements 11, 12, and 14. This allows the elements 11, 12, and 14 to be efficiently cooled by the refrigerant, and the elements 11, 12, and 14 can be maintained at an appropriate temperature. Furthermore, because the panel body 40 is molded to fit the positions of the elements 11, 12, and 14, the volume of the panel body 40 can be kept to a minimum, allowing for a compact cooling system.

[0035] In particular, in the above embodiment, the refrigerant flow path 50 is positioned approximately in the center of the thickness direction of the panel main body 40, so that the thickness of the panel main body 40 can be minimized and heat absorption from the elements 11, 12, and 14 and heat dissipation from the panel main body 40 can be maximized.

[0036] (3) Example of change The present invention is not limited to the above-described embodiment, and various modifications are possible as follows. i) The cross-sectional shape of the coolant flow path 50 is not limited to a circle, but may be any shape such as a rectangle, an oval, or an ellipse.

[0037] ii) The heights of elements 12 and 14 may be different. For example, if element 14 is taller than element 12, the bending process is performed in the following procedure when forming the pipe into a serpentine shape. Note that one pipe is bent in order from inlet 53 to outlet 54 in Figure 2.

[0038] 2, the pipe bends upward (toward the viewer) and then downward (toward the viewer) before returning to horizontal. When it leaves region P and re-enters region P, the pipe bends downward and then upward before returning to horizontal. In this way, a cooling pipe that rises parallel to the element 14 is obtained. Then, a mold is made following the shape of the cooling pipe, and the cooling pipe is cast-in, so that the panel body 40 also adheres tightly to the element 14.

[0039] iii) In the first embodiment, a single pipe is bent into a serpentine shape, but a serpentine-shaped cooling pipe can be produced by connecting U-shaped pipes as follows.

[0040] FIG. 5 is a plan view showing the cooling pipe 60 forming the refrigerant flow path 50. The cooling pipe 60 is made by connecting U-shaped pipes 61 shown in FIG. 4 . One end of the U-shaped pipe 61 is formed with an expanded pipe section 63 having a larger outer diameter than the remaining portion. The inner diameter of the expanded pipe section 63 is set slightly smaller than the outer diameter of the other end 62 of the U-shaped pipe 61. The other end 62 of another U-shaped pipe 61 is press-fitted into the expanded pipe section 63, thereby firmly and liquid-tightly joining the two. By connecting U-shaped pipes 61 one after another in this manner, the serpentine-shaped cooling pipe 60 is made. Note that the expanded pipe section 63 is formed by a pipe expansion process using, for example, a rolling-type pipe expansion tool, and therefore has a thinner wall thickness than the other portions. Furthermore, forming a tapered portion on the outer periphery of the edge of the other end 62 makes it easier to insert it into the expanded pipe section 63.

[0041] Straight pipes 64, 65 are connected to the U-shaped pipes 61 at both ends connected to the refrigerant inlets and outlets 53, 54. In this case, an expanded portion 63 is formed at the end of the pipe 64, and the other end 62 is formed at the end of the pipe 65.

[0042] 5, all pipes 61 are arranged on the same plane, but in order to form a refrigerant flow path 50 that matches the panel body 40 having the step portion 41 as shown in FIG. 1, the cooling pipe 60 is assembled as follows. That is, in FIG. 5, the U-shaped pipe 61 and the pipe 64 are connected in order from the left side, and at the portion indicated by arrow A, the U-shaped pipe 61 is twisted at a predetermined angle (for example, 45 degrees toward the back of the page), and the U-shaped pipe 61 is twisted. Expanded section The other end 62 of the U-shaped pipe 61 is press-fitted into 63 .

[0043] Next, in the portion indicated by arrow B, the U-shaped pipe 61 is twisted by a predetermined angle (for example, 45° toward the front of the paper in FIG. 4 ), and the other end 62 of the pipe 65 is press-fitted into the expanded portion 63 of the U-shaped pipe 61. As a result, the right-end U-shaped pipe 61 and the right-side portion of the U-shaped pipe 61 connected to the right-end U-shaped pipe 61 and the pipe 65 are arranged horizontally.

[0044] The cooling pipe 60 thus fabricated is set in a mold, the mold is closed, and molten metal is poured into the mold through the gate. In this way, as shown in Figure 1, a cooling panel 30 is formed, which has a vertical flow channel 51 arranged at a position inclined clockwise and a vertical flow channel 51 arranged alongside the vertical flow channel 51 in the horizontal direction.

[0045] According to the above-described modified example, the serpentine-shaped cooling pipe 60 is formed by joining U-shaped pipes 61, so that by connecting the U-shaped pipes 61 in a twisted state at the connection points, it is possible to easily form the three-dimensional cooling pipe 60. When a single pipe is bent into a serpentine shape, dimensional errors tend to occur due to springback of the material, but the above-described modified example provides sufficient dimensional accuracy.

[0046] iv) In the above modification, an expanded portion 63 is formed at one end of a U-shaped pipe 61, and the other end 62 of another U-shaped pipe 61 is press-fitted into the expanded portion 63 to connect the two, but any connection method can be used. For example, an annular protrusion can be formed at one end of the U-shaped pipe 61, a ring can be connected to the other end, and the annular protrusion can be press-fitted into the ring. Alternatively, the outer periphery of one end of the U-shaped pipe 61 can be cut to form a small diameter portion, and the inner periphery of the other end can be cut to form a large diameter portion. hole This large diameter hole Alternatively, the ends of the U-shaped pipes 61 may be welded together.

[0047] v) In the above modified example, U-shaped pipes 61 are connected together, but the vertical flow path 51 and the horizontal flow path 52 can be formed as separate parts, and the two can be connected at the expanded portion 63 and the other end 62 to form a serpentine shape.

[0048] 2. Second embodiment A second embodiment of the present invention will be described with reference to Fig. 6. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and their description will be omitted. As shown in Fig. 6, a capacitor 13 is mounted on a circuit board 10 together with an element 12 and an element 14 (not shown). The capacitor 13 is cylindrical, and a cooling panel (heat management panel) 70 is disposed so as to sandwich the capacitor 13 therebetween.

[0049] Cooling panel 70 is configured by molding refrigerant flow paths 90 inside a panel body 80 made of metal such as aluminum. Panel body 80 is configured with side wall portions 81 and 82 facing the side surfaces of condenser 13, a top wall portion 83 facing the top surface of condenser 13, and a bottom wall portion 84 extending laterally from the lower edge of one of side wall portions 82.

[0050] 6 and horizontal flow paths 92 connecting the ends of the vertical flow paths 91, and has a serpentine shape that moves back and forth in a direction perpendicular to the plane of the paper in each of the side wall portion 81, the top wall portion 83, the side wall portion 82, and the bottom wall portion 84. The vertical flow paths 91 at both ends are provided with a refrigerant inlet 93 and an outlet 94.

[0051] The bottom wall 84 contacts the elements 12 and 14 via the thermally conductive sheet 22. The side walls 81 and 82 and the top wall 83 contact the capacitor 13 via the thermally conductive filler 23. Because the outer peripheral surface of the capacitor 13 is a cylindrical curved surface, the inner surfaces of the side walls 81 and 82 are also cylindrical with gaps provided to match. From the perspective of thermal conductivity, the smaller the gap, the better, so the gap is determined taking into account the precision of the casting. If necessary, machining, such as cutting or polishing, is performed after casting. To accommodate this geometric relationship, the conductive filler 23 is filled to fill the gaps between the outer peripheral surface of the capacitor 13 and the inner surfaces of the side walls 81 and 82, enhancing the heat absorption effect of the capacitor 13.

[0052] In the cooling panel 70 of the second embodiment, a refrigerant such as water is injected through an inlet 93, passes through a serpentine-shaped refrigerant flow path 90, and is discharged from an outlet 94. During this time, heat generated by the elements 12, 14 and the condenser 13 is absorbed by the panel body 80, and the heat absorbed by the panel body 80 is dissipated into the refrigerant.

[0053] In the above-described cooling panel 70, both the refrigerant flow path 90 and the panel main body 80 are molded to fit the shape of the vertically elongated condenser 13, so that the refrigerant flow path 90 is located close to the condenser 13. This allows the refrigerant to efficiently cool the condenser 13, and the condenser 13 can be maintained at an appropriate temperature. Furthermore, because the panel main body 80 is molded to fit the shape of the condenser 13, the volume of the panel main body 80 can be kept to a necessary minimum, allowing for a compact cooling system.

[0054] In the above modified example, the height of element 14 can also be made higher than that of element 12. In that case, the lower wall portion 84 of panel body 80 is formed so as to sink downward and parallel from element 14 to element 12, and vertical flow path 91 is formed in a shape that follows the shape of the lower wall portion 84. [Industrial Applicability]

[0055] The present invention can be used in the field of heat management of heat-generating electronic components and electronic devices mounted on circuit boards, such as electric vehicles, inverters for robots, and game consoles. [Explanation of symbols]

[0056] 10...circuit board, 11, 12, 14...element, 13...capacitor, 21, 22...thermal conductive sheet, 23...thermal conductive filler, 30, 70...cooling panel (thermal management panel), 40, 80...panel body, 41 step portion, 50, 90...refrigerant flow path, 51, 91...vertical flow path, 52, 92...horizontal flow path, 53, 93...inlet, 54, 94...outlet, 60...cooling piping, 61...U-shaped pipe, 62...other end, 63...expanded portion, 64, 65...pipe, side wall portions 81, 82, top wall portion 83, bottom wall portion 84.

Claims

1. A thermal management panel having a refrigerant flow path inside the panel body, in which a metal tube is wrapped in molten metal, characterized in that both the refrigerant flow path and the panel body are molded to match the shape and / or position of the heat source so that it can be closely attached to a heat source with a three-dimensional shape and / or multiple heat sources of different heights.

2. 2. The thermal management panel according to claim 1, wherein the refrigerant flow path is disposed at approximately the center of the panel body in the thickness direction.

3. 3. The thermal management panel according to claim 1, wherein the refrigerant flow path is a three-dimensional flow path formed by bending one of the metal pipes into a predetermined shape.

4. A thermal management panel as described in claim 1 or 2, characterized in that the refrigerant flow path has a serpentine shape with multiple vertical flow paths extending in the planar direction of the panel body and horizontal flow paths connecting the ends of the vertical flow paths, and at least a portion of the horizontal flow paths is inclined with respect to the plane of the panel body to form a three-dimensional flow path.

5. 5. The thermal management panel according to claim 4, wherein the vertical flow passages are formed by fitting together ends of U-shaped pipes having the horizontal flow passages.

6. 3. The thermal management panel according to claim 1, wherein a thermally conductive sheet or a thermally conductive filler is interposed between the panel and the heat source.

7. 3. The thermal management panel according to claim 1, wherein the panel body has a three-dimensional shape and is in close contact with the side and top surfaces of the heat source.

8. 3. The thermal management panel according to claim 1, wherein the metal pipe is made of the same material as the molten metal.

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