A heat pipe radiator for chip cooling in a confined adiabatic space

Abstract

The application provides a heat pipe radiator for chip heat dissipation in a limited heat insulation space and a chip heat dissipation method using the heat pipe radiator. The radiator is provided with a groove near the surface of the chip to be cooled, a heat pipe is embedded in the groove, and the outer surface of the radiator is coated with an infrared radiation coating. The radiator is provided with bolt holes, other radiators are connected through the bolt holes, the chip to be cooled is clamped between at least two radiators, and the chip is firmly contacted with the heat pipe. The heat generated by the chip to be cooled is transferred to the heat pipe and expanded on the heat pipe, the heat pipe transfers the heat to the heat storage layer of the radiator for heat storage, and the stored heat is radiated to the external space through the infrared radiation coating on the surface of the radiator. The application can solve the technical problem that the effect of the conventional passive heat dissipation method is general and the chip heat dissipation in the limited heat insulation space cannot be well solved.

Description

Technical Field

[0001] This invention relates to the field of chip heat dissipation technology, and more specifically to a heat pipe radiator for chip heat dissipation in a confined, insulated space. Background Technology

[0002] In certain electronic devices used in aerospace, data centers, and other fields, to ensure the safety of core chips under accidental operating conditions, these chips are typically designed with individually insulated and sealed casings. For example, the outermost shell of the chip is made of highly insulating materials, and further encased in thermal insulation materials such as aerogel. This ensures that in the event of an accident such as a fire, heat from the external high-temperature environment will not be transferred into the casing and affect the safety of the core chip. While this design protects the core chip under extreme accidental conditions, it also prevents the heat generated by the core chip during normal operation from being dissipated in a timely manner through traditional heat conduction and convection. This causes the chip's temperature to rise continuously during operation, posing a significant risk to its safe and stable operation. Therefore, it is necessary to design an effective heat dissipation method to transfer the heat generated by the chip within this insulated space to the outside of the casing in a timely manner.

[0003] Currently, the mainstream heat dissipation methods are active and passive. Active heat dissipation includes fan cooling, pump-driven liquid cooling circuits, jet cooling, spray cooling, and immersion cooling. While active heat dissipation methods are highly efficient, they often have moving parts, require external power, are bulky, and have complex systems. Furthermore, due to space and volume constraints in electronic devices, the surrounding environment for core chip installations is often very confined, making active heat dissipation unsuitable for such situations. Passive heat dissipation includes heat pipes, vapor chambers (VC), thermal grease, thermal pads, and radiation coatings. When using passive heat dissipation for chips, all space is small and no external power source is required, meeting the heat dissipation requirements. However, current passive heat dissipation methods generally have limited effectiveness and cannot adequately address this heat dissipation need; therefore, there is a need to develop superior heat dissipation methods. Summary of the Invention

[0004] To address the shortcomings of existing technologies and to better and more promptly dissipate the heat generated by chips within confined thermal insulation spaces under normal operating conditions, this invention proposes a heat pipe radiator for chip heat dissipation within confined thermal insulation spaces. This addresses the technical problem that conventional passive heat dissipation methods in existing technologies are generally ineffective and cannot adequately solve the heat dissipation issues of chips within confined thermal insulation spaces.

[0005] The technical solution adopted in this invention is as follows: In a first aspect, a heat pipe radiator for chip heat dissipation in a confined thermally insulated space is provided. The radiator has a groove near the surface of the chip to be cooled, and a heat pipe is embedded in the groove. An infrared radiation coating is applied to the outer surface of the radiator. The radiator has bolt holes, and other radiators are connected by bolts, clamping the heat dissipation chip between at least two radiators.

[0006] In some embodiments, the groove is a plurality of parallel grooves, each groove having a heat pipe embedded therein; the contact surface between the heat pipe and the chip being cooled has a larger area than the area of ​​the chip being cooled.

[0007] In some embodiments, the radiator is a semi-cylindrical, irregularly shaped semi-cylindrical, or cuboid structure, and the heat pipe is an integral flat and straight structure, or a flat and straight structure at one end and a curved structure at the other end, or a flat and straight structure in the middle and a curved structure at both ends.

[0008] In some embodiments, the inner surface of the heat pipe is provided with a porous structure for wicking to promote coolant reflux.

[0009] In some embodiments, the radiator and heat pipe are made of copper, aluminum, or titanium alloy; the infrared radiation coating is made of graphene nano-ceramic heat dissipation coating or polyvinylidene fluoride coating.

[0010] In some implementations, the ratio of the radiator heat storage layer volume to the heat pipe volume should satisfy:

[0011] The volume of the radiator's thermal storage layer is V. R The density is Specific heat capacity is c R The heat pipe volume is Thickness is t h .

[0012] In some implementations, the heat pipe thickness t h The thickness d of the radiator heat storage layer should meet the following requirements: d>5t h .

[0013] In a second aspect, a chip heat dissipation method in a confined thermally insulated space is provided, which uses heat pipe radiators as described in the first aspect, connects at least two heat pipe radiators by bolts, and clamps the chip to be cooled between at least two heat pipe radiators with the same structure, so that the chip is in firm contact with the heat pipe. The heat generated by the heat dissipation chip is transferred to the heat pipe and spreads along the heat pipe. The heat pipe transfers the heat to the heat storage layer of the radiator for heat storage, and then the stored heat is radiated to the outside space through the infrared radiation coating on the surface of the radiator.

[0014] As can be seen from the above technical solution, the beneficial technical effects of the present invention are as follows: 1. The heat pipe radiator organically combines a heat pipe structure, a heat storage structure, and an infrared radiation coating. The heat pipe rapidly expands the heat generated on a small area of ​​the chip to a larger area, quickly transferring the heat to the radiator for storage. Finally, the heat is radiated into the external space in the form of infrared waves through the coating. In particular, the radiator's heat storage design greatly suppresses heat accumulation in electronic devices, effectively reducing their temperature.

[0015] 2. Heat pipe radiators can cool chips by clamping them on both sides or multiple sides. The size and distance of two or more radiators can be adjusted according to the actual size of the device being cooled. The bolts on the radiators are secure and easy to adjust, offering good flexibility. The overall structure of the heat pipe radiator is simple; the heat pipes are embedded within the radiator to form an integrated structure, without complex structures or redundant designs. The device is robust, reliable, and has low manufacturing costs. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0017] Figure 1 This is a schematic diagram of the design principle of the heat pipe radiator in an embodiment of the present invention; Figure 2 This is a schematic diagram of the explosion of the heat pipe radiator in an embodiment of the present invention; Figure 3 This is a three-dimensional schematic diagram of the heat pipe radiator in its assembled and operational state in an embodiment of the present invention; Figure 4 This is a schematic diagram of the radiator cross-section in an embodiment of the present invention; Figure 5 This is a schematic diagram of the heat pipe structure in an embodiment of the present invention; Figure 6 This is an optical microscope image of the surface coating of the heat pipe radiator in an embodiment of the present invention; Figure 7 This is a physical image of the heat pipe radiator in an embodiment of the present invention; Figure 8 This is a temperature comparison curve of SSD cards cooled by different cooling methods at room temperature in an embodiment of the present invention; Figure 9 This is a temperature curve diagram of SSD cards cooled in an oven using different cooling methods in an embodiment of the present invention; Figure 10 This is a long-term temperature test curve of a real high-speed SSD card cooled by a heat pipe radiator in an embodiment of the present invention. Figure 11This is a schematic diagram of the cuboid heat pipe radiator structure in an embodiment of the present invention; Figure 12 This is a schematic diagram of a heat pipe radiator structure combining an irregularly shaped semi-cylinder and an irregularly shaped heat pipe in an embodiment of the present invention. Figure label: 1-Heat pipe, 2-Radiator, 3-Radiation coating, 4-Bolt hole, 5-Chip. Detailed Implementation

[0018] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0019] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0020] Example This embodiment provides a design method for a heat pipe radiator for chip heat dissipation in a confined, insulated space. The design principle is as follows: Figure 1 As shown, the radiators on both sides of the chip have identical structures. The heat they generate is ultimately transferred to the external space through the path of "diffusion-transfer-storage-dissipation", achieving efficient cooling of the chip.

[0021] A heat pipe radiator mainly consists of multiple radiators and multiple heat pipes. Multiple parallel heat pipes are embedded in each radiator near the surface of the device being cooled. The outer surface of the radiator is coated with an infrared radiation coating. The number of radiators is determined by the shape of the chip. For thinner chips, one radiator is installed on both the top and bottom surfaces. For thicker chips or non-rectangular chips, in addition to one radiator on each of the top and bottom surfaces, more radiators can be installed on the sides where space allows. The size of the radiators installed on the sides can be smaller than those installed on the top and bottom surfaces.

[0022] Figure 2 This is a schematic diagram of an explosion of a heat pipe radiator according to an embodiment of the present invention. Figure 1 The design schematic diagram provides a 3D design demonstration, using the example of a thin chip with a radiator mounted on its top and bottom surfaces. Chip 5 is sandwiched between two identical radiators 2. Bolt holes 4 are designed on the radiators, and the two radiators are connected and fixed by bolts passing through these holes, ensuring a firm contact between the chip and the heat pipe 1. A radiation coating 3 is sprayed onto the outer surface of the radiators, allowing the heat generated by the chip to radiate into the external space.

[0023] In some embodiments, the heat-dissipating chip in operation is placed between multiple independent radiators, in close contact with the evaporation end of a heat pipe. The heat pipe area is larger than the area of ​​the heat-dissipating device at the contact surface between the heat pipe and the heat-dissipating chip. Heat generated by the heat-dissipating device is transferred to the heat pipe and spreads along it, effectively reducing the heat flux per unit area of ​​the heat-dissipating device. The heat pipe then rapidly transfers the heat to the radiators for heat storage, and finally, the stored heat is radiated into the external space through an infrared radiation coating on the surface of the radiators.

[0024] In other embodiments, when the external ambient temperature rises sharply (e.g., in the event of a fire), heat from the external environment is transferred to the device being cooled through the insulating shell and aerogel. The heat is first transferred to and stored in the radiator body, which acts as a buffer layer along the path of external heat transfer to the chip. Subsequently, it activates the infrared coating, radiating the stored heat into the external space, slowing down or even blocking heat transfer to the chip. Therefore, the heat pipe radiator proposed in this invention can dissipate the heat generated during the normal operation of electronic devices within a confined insulating space to the outside, while simultaneously suppressing the transfer of heat to the electronic devices inside the shell in the event of an external fire or other similar incidents.

[0025] In specific implementations, all radiators have the same structure. A single radiator can be a semi-cylindrical, cuboid, or various irregularly shaped structures designed according to the shape of the space with limited heat dissipation. Traditional heat pipe radiators typically have multiple fins on the heat pipe to increase the radiative heat dissipation area, and the heat pipe and radiating fins are independent entities (not an integrated design). This invention, however, changes the fin structure to a single solid piece to achieve heat storage, forming a heat storage pool. Multiple parallel grooves are designed on the surface of the radiator near the device being cooled for embedding the heat pipe. An infrared radiation coating is sprayed onto the outer surface of the radiator, with a rough surface structure to enhance the adhesion of the coating. The coating can radiate the heat stored in the radiator to the cold external space in the form of mid- and far-infrared waves. Finally, the radiator has multiple small holes, and bolts are used to securely connect two independent radiators. Figure 3 A three-dimensional schematic diagram showing the heat pipe radiator with bolts installed and in use.

[0026] like Figure 4 The heat pipe radiator of the present invention is described using a semi-cylindrical radiator as an example. The semi-cylindrical radiator has a radius R of 25 mm, a height H of 50 mm, and is made of aluminum with a specific heat capacity of approximately 900 J / (kg·K) and a density of 2700 kg / m³. 3The thermal conductivity is approximately 237 W / (m·K). Two parallel grooves are designed on the surface of the radiator 2 near the electronic components to embed the heat pipe 1. The grooves have a length H of 50 mm, a width w of 10.2 mm, and a depth h of 3 mm. The wall thickness t separating the two grooves is 1 mm. The width of the grooves is slightly larger than the width of the heat pipe to ensure that the heat pipe can be completely embedded within the radiator.

[0027] In a specific implementation, the portion of the heat pipe in contact with the heat-dissipating device is a flat, straight heat pipe, while the remaining portion can be a curved structure. For example, the heat pipe can be entirely flat and straight, or flat and straight at one end with a curved end, or flat and straight in the middle with curved ends. The flat structure ensures close contact with the heat-dissipating device. Since the heat transfer capacity of a curved heat pipe is lower than that of a straight heat pipe, the heat pipe of this invention is preferably entirely flat and straight, made of materials with high thermal conductivity such as copper, aluminum, or titanium alloys. The inner surface of the heat pipe has a porous wick structure, which facilitates the return of condensed liquid to the evaporation section, thereby enhancing the heat transfer capacity of the heat pipe. Different cooling media can be filled according to the cooling temperature requirements of the heat-dissipating device, such as deionized water, low-boiling-point R134a, or electronic fluorinated liquid, with a filling rate of 10-30%. Thanks to the equivalent high thermal conductivity of the heat pipe, the heat from the heat-dissipating device can be quickly transferred to the radiator. Figure 5 The length L of the heat pipe h It is 50 mm long and the width is W. h It is 10mm thick, with a thickness of t. h The diameter is 3 mm, and the material is copper. The heat pipe is filled with deionized water, with a filling rate of 20%.

[0028] The coating of this invention selects a coating with high infrared thermal emissivity, which is effective in the "atmospheric window" (wavelength mainly in the range of...). It has extremely high emissivity within an area of ​​8-13 µm, enabling it to efficiently radiate internal heat into external space in the form of infrared radiation. Preferred radiation coatings include graphene nano-ceramic heat dissipation coatings and polyvinylidene fluoride coatings. Figure 6 The image shown is a physical picture of the radiation coating according to an embodiment of the present invention. Under a 500X optical microscope, it can be seen that the surface structure after spraying is rough and the coating is firmly adhered to the surface of the radiator. Figure 7 Based on Figures 2-6 Photos of heat pipe radiators of different sizes designed and manufactured.

[0029] During the heat transfer process, let the temperature of the contact surface between the heat pipe and the electronic device be T1 (i.e., the temperature of the evaporating end of the heat pipe), the temperature of the contact surface between the heat pipe and the radiator's heat storage layer be T2 (i.e., the temperature of the condensing end of the heat pipe), and the temperature of the outer surface of the radiator's heat storage layer be T3; the thickness of the heat pipe is t. h The thermal conductivity is k h The volume of the radiator's thermal storage layer is V.R The density is Specific heat capacity is c R The thickness is d and the thermal conductivity is k. R .

[0030] Let the contact area between the heat pipe and the electronic device be A1, and the heat transferred be Q1; let the contact area between the heat pipe and the heat storage layer of the radiator be A2, and the heat transferred be Q2. These can be expressed as follows: (1) (2) Neglecting heat transfer from electronic devices to the heat pipe and radiative heat loss from the heat pipe to the radiator, the transferred heat Q1 and Q2 are equal, both denoted by Q. Assuming the heat transfer areas A1 and A2 are equal, both denoted by A, the heat transfer can be expressed as: (3) In existing technologies, the temperatures of the evaporator and condenser ends of heat pipes used for heat dissipation in electronic devices are typically 1-10 °C; here, we take 5 °C. The equivalent thermal conductivity k1 is approximately 5000-50000 W / (m·K), and we take 5000 W / (m·K). Therefore, the heat transfer can be expressed as: (4) On the other hand, the temperature rise of the radiator's heat storage layer after absorbing heat satisfies: (5) The heating rate is: (6) In equations (5) and (6), t represents time.

[0031] During the heat absorption process, it is necessary to ensure that the temperature rise rate of the radiator's heat storage layer after absorbing heat is very small, that is... It is very small, so it is necessary to ensure that the volume V R ,density and specific heat capacity c R It is very large. Density and specific heat capacity are intrinsic properties of a material, remaining constant once the material is determined; therefore, it is necessary to ensure that the volume V... R Make it as large as possible.

[0032] Generally, a slow heating rate will result in a temperature increase of no more than 1 °C per 60 seconds, meaning that formula (6) satisfies: ≤ (7) Combining formulas (4) and (6), we can obtain: ≤ (8) Ignoring the volume occupied by the gaps between heat pipes, the volume V of all heat pipes on a single radiator is... h satisfy: V h =At h (9) Therefore, in order to rapidly transfer the heat generated by electronic devices from the heat pipe to the radiator's heat storage layer, while ensuring that the temperature of the radiator's heat storage layer does not rise too quickly after absorbing heat, and to fully utilize the heat pipe's thermal conductivity and the radiator's heat storage capacity, the radiator's volume V... R and the volume V of the heat pipe h The ratio x should satisfy: (10) The thickness t of the heat pipe h The thickness d of the radiator should satisfy: d>5t h (11) Thickness d=4A c / C,A c Let C be the cross-sectional area of ​​the radiator and C be the perimeter of the radiator's cross-section.

[0033] The width and length of all heat pipes on a single radiator shall not be less than the width and length of the device being cooled, and the wall thickness t between parallel heat pipes on the radiator shall be ≤1 mm.

[0034] In some embodiments, the thickness of the radiant coating is 1 to 3% of the thickness of the radiator. This thickness of radiant coating can better dissipate the heat pipe temperature conducted by the radiator.

[0035] The following experimental data illustrates the heat dissipation effect of the heat pipe radiator in this application: Taking a high-capacity, high-speed data transfer integrated circuit SSD (Solid State Drive) card as an example, Figure 8 and Figure 9 Based on Figure 7 The temperature profile of the heat pipe radiator used to cool the SSD card is shown in the image. Figure 8 To be placed in the air, Figure 9The SSD card was placed in an oven. During the experiment, the SSD card was placed in the middle of a heat pipe radiator, which was then encased in a 3 cm thick aerogel to create a confined, insulated environment. The device was then placed in ovens at room temperature (23±1 ℃) and 100 ℃ to simulate normal operation and high-temperature conditions, respectively. The heat pipe radiator provided by this invention was compared with the thermal pads integrated into the SSD card and with commonly available heat pipe radiators. The experiment recorded the ambient temperature and the SSD card temperature throughout the entire process, from when the SSD card started processing and transferring data to when data transfer stopped. In the figure, "start" indicates a set transfer speed of 100 MB / s for the SSD card, and "stop" indicates the cessation of data transfer. Data transfer was stopped after 75 minutes in an air environment and after 10 minutes in an oven.

[0036] After data transmission ceases, under normal operating conditions, the temperatures of the thermal pad, the existing commercially available heat pipe radiator, and the cooling chip of the heat pipe radiator of this invention are approximately 84°C, 40°C, and 37°C, respectively. Therefore, the heat pipe radiator of this invention reduces the temperature by 47°C and 3°C compared to the original thermal pad and the existing commercially available heat pipe radiator, respectively.

[0037] After data transmission ceases, under a high-temperature environment of 100°C, the temperatures of the thermal pad, the existing commercially available heat pipe radiator, and the cooling chip of the heat pipe radiator of this invention are approximately 110°C, 77°C, and 48°C, respectively. Therefore, the heat pipe radiator of this invention reduces the temperature by 62°C and 29°C compared to the original thermal pad and the existing commercially available heat pipe radiator, respectively.

[0038] Figure 10 The temperature profile of the SSD card under 113 hours of testing using the heat pipe radiator in this embodiment is shown when the SSD card is in operation (data transfer speed 100 MB / s). During this test period, the temperature of the SSD card remained within a safe range and remained highly stable.

[0039] As can be seen from the above experiments, the heat pipe radiator proposed in this invention exhibits superior cooling characteristics, especially in high-temperature environments where the cooling effect is better.

[0040] In some embodiments, the heat pipe radiator can also be Figure 11 The rectangular heat pipe radiator structure, and Figure 12 Configurations such as the heat pipe radiator structure that combines irregular semi-cylinders and irregular heat pipes are all integrated structures in which heat pipes are embedded in the radiator.

[0041] The heat pipe radiator design method and the heat pipe radiator prepared according to this invention organically combine a heat pipe structure, a heat storage structure, and an infrared radiation coating. The heat pipe rapidly expands the heat generated on a small area of ​​the chip to a larger area, quickly transferring the heat to the radiator for storage. Finally, the heat is radiated into the external space in the form of infrared waves through the coating. In particular, the heat storage design of the radiator can greatly suppress the accumulation of heat in electronic devices, effectively reducing the temperature of the electronic devices.

[0042] Heat pipe radiators can cool chips by clamping them on both sides or multiple sides. The size and distance of two or more radiators can be adjusted according to the actual size of the device being cooled. The bolts on the radiators are secure and easy to adjust, offering good flexibility. The overall structure of the heat pipe radiator is simple; the heat pipes are embedded within the radiator to form an integrated structure, without complex structures or redundant designs. The device is robust, reliable, and has low manufacturing costs.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A heat pipe radiator for chip heat dissipation in a confined, insulated space, characterized in that, The radiator has a groove near the surface of the chip being cooled, and a heat pipe is embedded in the groove. The outer surface of the radiator is coated with an infrared radiation coating. The radiator has bolt holes, and other radiators are connected by bolts, clamping the heat dissipation chip between at least two radiators.

2. The heat pipe radiator for chip heat dissipation in a confined, insulated space according to claim 1, characterized in that, The groove consists of multiple parallel grooves, each containing a heat pipe; the contact surface between the heat pipe and the chip being cooled has a larger area than the chip being cooled.

3. The heat pipe radiator for chip heat dissipation in a confined, insulated space according to claim 1, characterized in that, The radiator is a semi-cylindrical, irregularly shaped semi-cylindrical, or cuboid structure, and the heat pipe is an integral flat and straight structure, or a flat and straight structure at one end and a curved structure at the other end, or a flat and straight structure in the middle and a curved structure at both ends.

4. The heat pipe radiator for chip heat dissipation in a confined, insulated space according to claim 1, characterized in that, The inner surface of the heat pipe is provided with a porous structure for absorbing liquid to promote the return flow of coolant.

5. The heat pipe radiator for chip heat dissipation in a confined, insulated space according to claim 1, characterized in that, The radiator and heat pipe are made of materials such as copper, aluminum, or titanium alloy; the infrared radiation coating is made of graphene nano-ceramic heat dissipation coating or polyvinylidene fluoride coating.

6. The heat pipe radiator for chip heat dissipation in a confined, insulated space according to claim 1, characterized in that, The ratio of the radiator's heat storage layer volume to the heat pipe volume should satisfy: The volume of the radiator's thermal storage layer is V. R The density is Specific heat capacity is c R The heat pipe volume is Thickness is t h .

7. The heat pipe radiator for chip heat dissipation in a confined, insulated space according to claim 1, characterized in that, heat pipe thickness t h The thickness d of the radiator heat storage layer should meet the following requirements: d>5t h ...

8. A method for heat dissipation of a chip within a confined, insulated space, characterized in that, Using the heat pipe radiator as described in any one of claims 1-7, at least two heat pipe radiators are connected by bolts, and the chip to be cooled is sandwiched between at least two heat pipe radiators with the same structure, so that the chip is in firm contact with the heat pipe. The heat generated by the heat dissipation chip is transferred to the heat pipe and spreads along the heat pipe. The heat pipe transfers the heat to the heat storage layer of the radiator for heat storage, and then the stored heat is radiated to the outside space through the infrared radiation coating on the surface of the radiator.

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