A heat dissipation device integrated with a valveless piezoelectric pump

Abstract

The application provides a heat dissipation device integrated with a valveless piezoelectric pump, which comprises a valveless piezoelectric pump and a flexible heat dissipation plate. The valveless piezoelectric pump has a pump body, a pump cover and a piezoelectric vibrator. The pump body is provided with a pump cavity, a pump inlet, a pump outlet, an inlet cone tube and an outlet cone tube. The pump cover covers the top of the pump body. The piezoelectric vibrator is fixed below the pump cover. The bottom of the central area of the pump cavity is provided with a raised flat surface. The depth of the central area is lower than that of the peripheral area, which improves the bubble tolerance. The inlet and outlet of the internal flow channel of the flexible heat dissipation plate are located at one end of the heat dissipation plate. The valveless piezoelectric pump is attached to one end of the flexible heat dissipation plate. The inlet and outlet of the flow channel are respectively connected with the pump outlet and the pump inlet, forming a circulating cooling channel. The valveless piezoelectric pump eliminates the risk of fatigue failure of the valve plate. The reciprocating oscillation flow provided by the valveless piezoelectric pump strengthens the heat exchange between the fluid and the wall surface. The flexible heat dissipation plate makes the whole device light and thin and can be flexibly folded, which is suitable for efficient liquid cooling heat dissipation of portable electronic devices.

Description

Technical Field

[0001] This invention belongs to the field of heat dissipation technology for electronic devices, and particularly relates to a heat dissipation device integrating a valveless piezoelectric pump. Background Technology

[0002] In recent years, electronic devices have developed rapidly, especially portable electronic devices such as mobile phones and laptops. The density of integrated circuits in the internal electronic chips has increased rapidly, leading to a sharp increase in heat generation and a rise in local heat flux density. The resulting high temperature seriously affects the operating performance and lifespan of the core chip, making the system unstable and significantly reducing the user experience.

[0003] Traditional heat dissipation solutions often employ air cooling with fans or heat sinks. These solutions are generally large and have low heat dissipation efficiency, making them unsuitable for the heat dissipation needs of today's thinner and more portable electronic devices. To address these issues, liquid-cooled patch heat sinks have gained increasing attention. These devices use a power pump to drive the cooling medium to circulate within the channels of a heat sink, removing heat from the heat source. The power pump is the core component of the liquid-cooled patch heat sink, and its reliability directly affects the stability of the entire heat dissipation system. For example, the invention patent with authorization announcement number CN116867251B discloses a heat dissipation device and electronic device that uses a power pump connected to a heat dissipation vapor chamber with internal channels to form a circulating cooling path. The power pump can be a valved piezoelectric pump with a movable valve plate structure. However, while valved piezoelectric pumps can achieve directional liquid delivery, the movable valve plate structure is prone to fatigue failure during long-term high-frequency vibration operation. This can cause the piezoelectric pump to fail to deliver the liquid medium, leading to the heat dissipation device stopping operation and severely impacting the reliability of the electronic device.

[0004] Valveless piezoelectric pumps, lacking movable valve plates, eliminate the risk of valve plate fatigue failure in principle, offering advantages such as simple structure and high reliability. However, valveless piezoelectric pumps have a very low volumetric compression ratio. When conveying liquid media containing air bubbles, these air bubbles are difficult to expel, leading to a significant decrease in pump output performance or even complete failure to convey media. In liquid cooling applications, trace amounts of air bubbles inevitably mix into the cooling medium during filling and operation. Therefore, the low bubble tolerance of valveless piezoelectric pumps limits their application in liquid cooling.

[0005] Furthermore, existing liquid cooling devices mostly use rigid heat sinks, which are difficult to adapt to the confined and irregular installation spaces inside portable electronic devices, and also cannot meet the requirements of foldable electronic devices for flexible heat dissipation solutions. Therefore, how to retain the high reliability advantages of valveless piezoelectric pumps while solving their low bubble tolerance problem, and effectively integrate them with flexible heat sinks to achieve efficient, thin, and reliable liquid cooling, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a heat dissipation device integrating a valveless piezoelectric pump, aiming to simultaneously solve the problems of easy fatigue damage of valve plates in valved piezoelectric pumps, low bubble tolerance in valveless piezoelectric pumps, and the difficulty of existing heat dissipation devices in meeting the requirements for lightweight and flexible installation.

[0007] The valveless piezoelectric pump used in this invention lacks a movable valve plate structure. It utilizes the different flow resistances of the tapered tube in the diffusion and contraction flow directions to achieve directional delivery of the cooling medium, effectively eliminating the risk of valve plate fatigue failure. Simultaneously, by reducing the pump chamber volume and increasing the volumetric compression ratio, air bubbles within the pump chamber are more easily expelled, enhancing the valveless piezoelectric pump's ability to deliver air-bearing liquid media. Furthermore, this invention integrates the valveless piezoelectric pump with a flexible heat sink with internal flow channels, enabling the entire heat dissipation device to adapt to the confined and irregular installation spaces within portable electronic devices and meeting the requirements of foldable electronic devices for flexible heat dissipation solutions.

[0008] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0009] A heat dissipation device integrating a valveless piezoelectric pump includes at least one valveless piezoelectric pump and a flexible heat sink.

[0010] The valveless piezoelectric pump has a pump body, a pump cover, and a piezoelectric vibrator. The pump body is provided with a pump cavity, a pump inlet, a pump outlet, an inlet cone tube, and an outlet cone tube. The inlet cone tube is connected to the pump inlet and the pump cavity, respectively. The outlet cone tube is connected to the pump cavity and the pump outlet, respectively. The pump cover is placed on top of the pump body and seals the pump cavity, the inlet cone tube, and the outlet cone tube of the pump body. The piezoelectric vibrator is fixed below the pump cover. The depth of the central region of the pump cavity is lower than the depth of the peripheral region of the pump cavity.

[0011] The flexible heat sink has internal flow channels, and the inlet and outlet of the flow channels are both located at one end of the flexible heat sink.

[0012] The valveless piezoelectric pump is attached and fixed to one end of the flexible heat sink. The inlet and outlet of the flow channel are connected to the pump outlet and pump inlet of the valveless piezoelectric pump, respectively, to form a circulating cooling path.

[0013] In the above scheme, the pump body is also provided with an inlet buffer chamber and an outlet buffer chamber;

[0014] The inlet cone and outlet cone have the same structure and are arranged coaxially and equidistant from the center of the pump chamber. The narrow end of the inlet cone is connected to one end of the inlet buffer chamber, and the wide end is connected to the pump chamber. The narrow end of the outlet cone is connected to the pump chamber, and the wide end is connected to one end of the outlet buffer chamber. The other end of the inlet buffer chamber is connected to the pump inlet, and the other end of the outlet buffer chamber is connected to the pump outlet.

[0015] In the above scheme, a raised plane is provided at the bottom of the central region of the pump cavity, and the distance between the raised plane and the top of the pump cavity is less than the distance between the bottom of the peripheral region of the pump cavity and the top of the pump cavity.

[0016] Furthermore, the depth ratio of the central region of the pump cavity to the depth of the surrounding region is 0.1 to 0.4.

[0017] In the above scheme, the length of the inlet cone tube and the outlet cone tube is 0.8~4mm, the cone angle is 5°~15°, the depth is 0.08~0.2mm, the minimum cross-sectional width is 0.08~0.4mm, and the radius of the narrow end fillet is 0.08~0.4mm.

[0018] In the above scheme, the flexible heat dissipation plate includes an upper layer, a middle layer and a lower layer in the thickness direction. The flow channel is located in the middle layer, and the cooling medium is sealed in the middle layer flow channel through the upper layer and the lower layer. The flow channel depth is 0.1~0.5mm.

[0019] Furthermore, the upper, middle and lower layers of the flexible heat sink are all made of thin film materials, and the thin film materials are one or more of LCP, COP, EVA, carbon fiber, glass fiber cloth or FCCL materials.

[0020] In the above scheme, the flow channels within the flexible heat dissipation plate include a first flow channel, a second flow channel, a third flow channel, and a fourth flow channel;

[0021] The first flow channel is connected to the flow channel inlet, the left end of the second flow channel is connected to the upper end of the first flow channel, and the left end of the third flow channel is connected to the lower end of the first flow channel.

[0022] The fourth flow channel is connected to the flow channel outlet, the upper end of the fourth flow channel is connected to the right end of the second flow channel, and the lower end of the fourth flow channel is connected to the right end of the third flow channel.

[0023] Furthermore, both the second and third flow channels are dual-flow parallel structures.

[0024] In the above scheme, the flexible heat dissipation plate is provided with a liquid filling port and a liquid outlet.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. Compared with valved piezoelectric pumps, the valveless piezoelectric pump used in this invention has no moving valve plate structure, resulting in high reliability and meeting the requirements for long-term stable operation. By having a lower depth in the central region of the pump cavity than the surrounding region, combined with a raised plane, the volumetric compression ratio and bubble tolerance of the pump cavity are effectively improved. Compared with the unidirectional pulsating flow of a valved piezoelectric pump, the reciprocating oscillating flow of the valveless piezoelectric pump can increase the instability of the fluid, enhance the degree of turbulence, and disrupt the thermal boundary layer, thereby strengthening the heat exchange between the fluid and the wall. The heat dissipation device integrating the valveless piezoelectric pump and the flexible heat sink is thin and lightweight and can be flexibly folded, making it suitable for thin and lightweight portable electronic devices.

[0027] 2. This invention integrates a valveless piezoelectric pump with a flexible heat sink with internal flow channels, and fixes the valveless piezoelectric pump to one end of the flexible heat sink. The inlet and outlet of the flow channels are connected to the pump outlet and pump inlet, respectively, forming a circulating cooling path. This achieves a lightweight, thin, and flexibly foldable liquid cooling device that can adapt to the small and irregular installation space inside portable electronic devices and meet the requirements of foldable electronic devices for flexible heat dissipation solutions. Simultaneously, the depth of the central region of the pump cavity is lower than the depth of the surrounding region, effectively reducing the pump cavity volume and increasing the pump cavity volume compression ratio, making it easier to expel air bubbles within the pump cavity and improving the valveless piezoelectric pump's ability to transport liquid media containing air bubbles.

[0028] 3. By setting an inlet buffer chamber and an outlet buffer chamber on the pump body, and setting the inlet cone pipe and the outlet cone pipe to be structurally identical, coaxially arranged and equidistant from the center of the pump cavity, the fluid flow path on both sides of the pump cavity is symmetrical, which is beneficial to the uniformity of the pressure distribution inside the pump cavity and improves the working stability of the pump.

[0029] 4. By setting a raised plane in the central region of the pump cavity, the present invention reduces the effective volume of the pump cavity and increases the volumetric compression ratio of the pump cavity, thereby improving the conveying capacity of the valveless piezoelectric pump for liquid media containing air bubbles.

[0030] 5. The present invention limits the ratio of the depth of the central region of the pump cavity to the depth of the surrounding region to 0.1~0.4. Within this ratio range, the volumetric compression ratio of the pump cavity is effectively improved, while avoiding the problem of excessive fluid flow resistance or processing difficulties caused by the central region being too shallow. This ensures the effective discharge of air bubbles and maintains the normal suction and discharge performance of the pump.

[0031] 6. This invention limits the length of the inlet and outlet tapered tubes to 0.8~4mm, the cone angle to 5°~15°, the depth to 0.08~0.2mm, the minimum cross-sectional width to 0.08~0.4mm, and the radius of the narrow end fillet to 0.08~0.4mm. Within the above parameter range, the flow resistance of the tapered tube differs significantly between the diffusion and contraction directions, enabling higher net flow rate and output pressure to be obtained under the same piezoelectric oscillator drive conditions. Furthermore, the above dimensional range is compatible with conventional micromachining processes, facilitating mass production.

[0032] 7. This invention uses a three-layer structure for the flexible heat sink, with the flow channel located in the middle layer. The cooling medium is sealed within the middle flow channel by the upper and lower layers, and the flow channel depth is 0.1~0.5mm. The three-layer thin-film encapsulation structure makes the heat sink thin and flexible, allowing it to bend within the internal space of electronic devices. The shallow depth of the microchannels helps to increase the contact area between the cooling medium and the channel wall, thereby improving heat exchange efficiency.

[0033] 8. The present invention uses LCP, COP, EVA, carbon fiber, glass fiber cloth or FCCL material as the film material of the flexible heat sink, which has good flexibility and bending resistance.

[0034] 9. The present invention arranges the flow channels in the flexible heat sink so that after the cooling medium enters from the flow channel inlet, it is diverted through the first flow channel to the second and third flow channels on the upper and lower sides, and then converges on the right side to the fourth flow channel before flowing out from the flow channel outlet. This increases the contact area between the flow channel and the heat sink wall and improves the heat exchange efficiency.

[0035] 10. This invention sets the second and third flow channels as a parallel dual-flow channel structure, further increasing the contact area between the flow channels and the wall.

[0036] The increased contact area, without increasing the channel depth, improves the heat exchange area and enhances heat dissipation efficiency. At the same time, the parallel dual-channel structure makes the temperature distribution on the upper and lower surfaces of the heat sink more uniform, avoiding localized overheating. Attached Figure Description

[0037] Figure 1 This is a top view of a heat dissipation device for an integrated valveless piezoelectric pump according to an embodiment of the present invention;

[0038] Figure 2 yes Figure 1 Side view;

[0039] Figure 3 This is a front sectional view of a valveless piezoelectric pump;

[0040] Figure 4 yes Figure 3 AA-direction cross section;

[0041] Figure 5 yes Figure 3 A partial enlarged view of pump chamber I;

[0042] Figure 6 yes Figure 4 A magnified view of a section of section II;

[0043] Figure 7 yes Figure 2 BB-direction cross-section;

[0044] Figure 8 This is a schematic diagram of the working principle of the valveless piezoelectric pump in the suction process of this invention;

[0045] Figure 9 This is a schematic diagram of the working principle of the internal flow channel of the flexible heat dissipation plate in the suction process of the present invention;

[0046] Figure 10 This is a schematic diagram of the working principle of the valveless piezoelectric pump in the discharge process of this invention;

[0047] Figure 11 This is a schematic diagram of the working principle of the internal flow channel of the flexible heat dissipation plate in the discharge process of the present invention;

[0048] Figure 12 This is a simulation diagram of the flow calculation region of the heat dissipation device integrating a valveless piezoelectric pump according to the present invention;

[0049] Figure 13 This is a curve showing the change of instantaneous inlet and outlet flow rates over time during one cycle in the heat dissipation device of the integrated valveless piezoelectric pump of this invention.

[0050] In the diagram: 1. Valveless piezoelectric pump; 2. Flexible heat sink; 3. Pump outlet; 4. Pump inlet; 5. Filling port; 6. Outlet; 7. Flow channel inlet; 8. Flow channel outlet; 9. Pump cover; 10. Outlet buffer chamber; 11. Piezoelectric vibrator; 12. Inlet buffer chamber; 13. Pump body; 14. Outlet cone tube; 15. Pump chamber; 16. Inlet cone tube; 17. First flow channel; 18. Second flow channel; 19. Fourth flow channel; 20. Third flow channel. Detailed Implementation

[0051] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0052] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "front," "rear," "left," "right," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0053] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0054] Figure 1-4 The image shows a preferred embodiment of the heat dissipation device for the integrated valveless piezoelectric pump, which includes at least one valveless piezoelectric pump 1 and a flexible heat sink 2.

[0055] The valveless piezoelectric pump 1 has a pump body 13, a pump cover 9, and a piezoelectric vibrator 11. The pump body 13 is provided with a pump chamber 15, a pump inlet 4, a pump outlet 3, an inlet cone tube 16, and an outlet cone tube 14. The inlet cone tube 16 is connected to the pump inlet 4 and the pump chamber 15, respectively. The outlet cone tube 14 is connected to the pump chamber 15 and the pump outlet 3, respectively. The pump cover 9 covers the pump body 13 and seals the pump chamber 15, the inlet cone tube 16, and the outlet cone tube 14 of the pump body 13. The piezoelectric vibrator 11 is fixed below the pump cover 9. The depth of the central region of the pump chamber 15 is lower than the depth of the peripheral region of the pump chamber 15.

[0056] The flexible heat sink 2 has a flow channel inside, and the upper and lower surfaces of the flow channel are encapsulated with thin film material. The inlet 7 and outlet 8 of the flow channel are both located at one end of the flexible heat sink 2.

[0057] The valveless piezoelectric pump 1 is attached and fixed to one end of the flexible heat sink 2. The inlet 7 and outlet 8 of the flow channel are respectively connected to the pump outlet 3 and pump inlet 4 of the valveless piezoelectric pump 1, forming a circulating cooling path. The cooling medium in the cooling path is a liquid, such as deionized water.

[0058] This invention integrates a valveless piezoelectric pump 1 with a flexible heat sink 2 having internal flow channels, and fixes the valveless piezoelectric pump 1 to one end of the flexible heat sink 2. The inlet 7 and outlet 8 of the flow channels are connected to the pump outlet 3 and pump inlet 4 respectively to form a circulating cooling path. This invention realizes a liquid cooling heat dissipation device with a thin and flexible overall structure that can be flexibly folded. It can adapt to the small and irregular installation space inside portable electronic devices and meet the requirements of foldable electronic devices for flexible heat dissipation solutions.

[0059] The pump cover 9 and pump body 13 of this invention can be made of metal, plastic or silicon, and plastic is preferred in this embodiment. The piezoelectric vibrator 11 is made of a piezoelectric ceramic sheet and an elastic metal sheet bonded together. The pump outlet 3, pump inlet 4, pump chamber 15, outlet buffer chamber 10, inlet buffer chamber 12, outlet cone tube 14 and inlet cone tube 16 are processed on the pump body 13 by etching or machining.

[0060] The inlet cone tube 16 and outlet cone tube 14 have the same structure and are coaxially arranged, equidistant from the center of the pump chamber 15. The narrow end of the inlet cone tube 16 is connected to one end of the inlet buffer chamber 12, and the wide end is connected to the pump chamber 15. The narrow end of the outlet cone tube 14 is connected to the pump chamber 15, and the wide end is connected to one end of the outlet buffer chamber 10. The other end of the inlet buffer chamber 12 is connected to the pump inlet 4, and the other end of the outlet buffer chamber 10 is connected to the pump outlet 3. The pump cover 9 and the pump body 13 are bonded together by bonding or adhesive. The piezoelectric vibrator 11 is fixed below the pump cover 9 by adhesive.

[0061] By providing an inlet buffer chamber 12 and an outlet buffer chamber 10 on the pump body 13, and by setting the inlet cone pipe 16 and the outlet cone pipe 14 to be structurally identical, coaxially arranged, and equidistant from the center of the pump cavity 15, the fluid flow paths on both sides of the pump cavity 15 are symmetrical, which is beneficial to the uniformity of the internal pressure distribution of the pump cavity 15 and improves the working stability of the pump. The pump cover 9 is sealed to the pump body 13 by bonding or adhesive, ensuring the sealing of the internal cavity and flow channel of the pump body 13 and preventing the leakage of cooling medium.

[0062] Reference Figure 4 and Figure 5The pump chamber 15 is divided into a central region, a peripheral region communicating with the inlet cone pipe 16, and a peripheral region communicating with the outlet cone pipe 14. The depth of the central region of the pump chamber is h2, and the depth of the peripheral region communicating with the outlet cone pipe 14 and the inlet cone pipe 16 is h1. The depths of the outlet buffer chamber 10, the inlet buffer chamber 12, the outlet cone pipe 14, and the inlet cone pipe 16 are also h1. The ratio of h2 to h1 is 0.1 to 0.4. The volume of the pump chamber 15 decreases as the ratio of h2 to h1 decreases, and its volumetric compression ratio increases, thereby improving the ability to transport liquid media containing air bubbles.

[0063] Through multiple cutting or chemical etching processes, a raised plane is formed at the bottom of the central region of the pump cavity 15. The distance between the raised plane and the top of the pump cavity 15 is less than the distance between the bottom of the peripheral region of the pump cavity 15 and the top of the pump cavity 15.

[0064] The raised plane reduces the effective volume of the central region of the pump chamber 15, thereby increasing the volumetric compression ratio of the pump chamber 15. When the cooling medium contains air bubbles, the higher compression ratio can compress the air bubbles to a smaller volume, making it easier for the air bubbles to be discharged from the pump chamber 15 with the fluid, thus improving the valveless piezoelectric pump's ability to transport air-containing liquid media.

[0065] The ratio of the depth of the central region to the depth of the surrounding region of the pump chamber 15 is 0.1 to 0.4. Within this range, the volumetric compression ratio of the pump chamber is effectively improved, while avoiding problems such as excessive fluid flow resistance or processing difficulties caused by an overly shallow central region. This ratio range, through reasonable design, ensures both the effective discharge of air bubbles and the maintenance of normal pump suction and discharge performance.

[0066] The inlet tapered tube 16 and the outlet tapered tube 14 have the same structural dimensions, such as... Figure 6 As shown, taking the inlet tapered tube 16 as an example, the narrow end of the inlet tapered tube 16 is connected to the inlet buffer chamber 12, with a rounded transition on the side wall. The radius of the rounded corner r is 0.08 ~ 0.4 mm. The wide end of the inlet tapered tube 16 is connected to the pump chamber 15, with a sharp corner on the side wall. The width d at the narrowest point of the inlet tapered tube 16 is 0.08 ~ 0.4 mm, the cone angle θ is 5º ~ 15º, and the length L is 0.8 ~ 4 mm. Within the above parameter range, the flow resistance of the tapered tube differs significantly between the diffusion and contraction directions, enabling higher net flow rate and output pressure to be obtained under the same piezoelectric oscillator driving conditions. Furthermore, the above dimensional range is compatible with conventional micromachining processes, facilitating mass production.

[0067] Figure 12 This is a simulation diagram of the flow calculation region of the micropump in the heat dissipation device of the integrated valveless piezoelectric pump of the present invention. Figure 13 It is a curve showing the change of instantaneous inlet and outlet flow rates over time within one cycle of a micropump.

[0068] In this embodiment, a micropump with a pump chamber diameter of 9mm is used as a case study for numerical simulation. Figure 13 This is the instantaneous flow rate curve of the micropump inlet and outlet within one cycle. The flow rate is positive in the first half of the cycle, indicating that the piezoelectric vibrator is displaced upwards, and fluid is drawn into the pump chamber from both the inlet and outlet, with the inlet flow rate exceeding the outlet flow rate. The flow rate is negative in the second half of the cycle, indicating that the piezoelectric vibrator is displaced downwards, and fluid is discharged from the pump chamber through both the inlet and outlet, with the outlet flow rate exceeding the inlet flow rate (i.e., the inlet flow rate is less than the outlet flow rate). Within one vibration cycle, the fluid is directionally transported from the inlet to the outlet. After integrating the instantaneous flow rates, the micropump can achieve a flow rate of 4.9 ml / min at a driving frequency of 300 Hz.

[0069] like Figure 7 As shown, the flow channels within the flexible heat sink 2 of this embodiment are arranged symmetrically from top to bottom. The flow channels within the flexible heat sink 2 include a first flow channel 17, a second flow channel 18, a third flow channel 20, and a fourth flow channel 19. The first flow channel 17 is connected to the flow channel inlet 7, the left end of the second flow channel 18 is connected to the upper end of the first flow channel 17, the left end of the third flow channel 20 is connected to the lower end of the first flow channel 17, and the fourth flow channel 19 is connected to the flow channel outlet 8. The upper end of the fourth flow channel 19 is connected to the right end of the second flow channel 18, and the lower end of the fourth flow channel 19 is connected to the right end of the third flow channel 20.

[0070] In this flow channel arrangement, both the second flow channel 18 and the third flow channel 20 are parallel dual-flow channel structures. After the cooling medium enters from the flow channel inlet 7, it is split into the second flow channel 18 and the third flow channel 20 on the upper and lower sides through the first flow channel 17, and then converges on the right side to the fourth flow channel 19 before flowing out from the flow channel outlet 8. This increases the contact area between the flow channel and the heat sink wall, thereby improving the heat exchange efficiency.

[0071] The flexible heat dissipation plate 2 is equipped with a filling port 5 and a liquid outlet 6, which facilitates the filling of cooling medium after the device is assembled. The medium is poured in through the filling port 5 and fills all flow areas. After filling, the filling port 5 and the liquid outlet 6 are sealed with UV-cured resin or epoxy resin adhesive. Both UV-cured resin and epoxy resin adhesive have good bonding strength and chemical corrosion resistance, and can reliably seal the cooling medium for a long time to prevent leakage.

[0072] The length of the flow channel is given according to the space dimensions of the electronic equipment, the width of the flow channel is 0.5 ~ 3 mm, and the depth of the flow channel is 0.1 ~ 0.5 mm. The flexible heat sink 2 is made of flexible material and includes an upper layer, a middle layer, and a lower layer in the thickness direction. The flow channel is located in the middle layer, and the cooling medium is sealed in the middle layer flow channel through the upper and lower layers. The flow channel depth is 0.1 ~ 0.5 mm, which makes the overall thickness of the heat sink thin and flexible, and can be bent according to the internal space of the electronic equipment. The small depth of the microchannel flow channel is conducive to increasing the contact area between the cooling medium and the flow channel wall, thereby improving the heat exchange efficiency.

[0073] This results in a thin and flexible heat sink that can be bent to fit the internal space of electronic devices; the shallow depth of the microchannels increases the contact area between the cooling medium and the channel walls, thereby improving heat exchange efficiency.

[0074] In this embodiment, both the second flow channel 18 and the third flow channel 20 are dual-flow-channel parallel structures. The dual-flow-channel parallel structure further increases the contact area between the flow channel and the wall, increasing the heat exchange area without increasing the flow channel depth, which is beneficial to improving heat dissipation efficiency; at the same time, the dual-flow-channel parallel structure makes the temperature distribution on the upper and lower surfaces of the heat sink more uniform, avoiding local overheating.

[0075] In this embodiment, the upper, middle, and lower layers of the flexible heat sink 2 are all thin-film materials, selected from one or more of the following: LCP (liquid crystal polymer), COP (cyclic olefin polymer), EVA (ethylene-vinyl acetate copolymer), carbon fiber, fiberglass cloth, or FCCL (flexible copper clad laminate). LCP and COP exhibit extremely low moisture absorption and excellent dimensional stability; EVA possesses good flexibility and low-temperature performance; carbon fiber and fiberglass cloth improve the mechanical strength and dimensional stability of the heat sink; and FCCL combines flexibility and thermal conductivity. All of these materials can be used to form sealed channels through thin-film encapsulation processes, meeting the requirements of portable electronic devices for thinness and bending reliability. Using these materials as the thin-film materials for the flexible heat sink 2 provides excellent flexibility and bending resistance, fulfilling the requirements of portable electronic devices for thinness and bending reliability.

[0076] The working principle of this invention is as follows: When an alternating voltage signal of a certain frequency, such as a sine wave or rectangular wave signal, is applied to the piezoelectric vibrator 11, the piezoelectric vibrator 11 will bend and deform and vibrate in accordance with the voltage change, driving the cooling medium in the pump chamber 15 and the flow channel to flow. A complete vibration cycle can be divided into two processes: upward displacement and downward displacement of the piezoelectric vibrator 11.

[0077] like Figure 8As shown, when the piezoelectric vibrator 11 moves upward, the volume of the pump chamber 15 increases. Cooling medium is drawn into the pump chamber 15 from the pump outlet 3 and pump inlet 4 via the outlet buffer chamber 10, outlet cone 14, inlet buffer chamber 12, and inlet cone 16, respectively. This process is called the suction process. At this time, the flow in the outlet cone 14 is in the contraction direction, with a flow rate of Q. n The flow inside the inlet cone tube 16 is in the diffusion direction, and the flow rate is Q. d Based on the tapered tube structure design, the flow resistance in the contraction direction is greater than that in the diffusion direction, and the flow rate Q n Less than Q d That is, during the suction process, the flow rate drawn in through pump outlet 3 is less than the flow rate drawn in through pump inlet 4, and the difference is Q. d -Q n .

[0078] like Figure 9 As shown, during the suction process, the cooling medium in the flexible heat sink 2 channel is drawn in from the flow channel inlet 7 connected to the pump outlet 3 and the flow channel outlet 8 connected to the pump inlet 4, with flow rates Q and Q, respectively. n and Q d The first flow channel 17, which is connected to the flow channel inlet 7, has a flow rate of Q at both its upper and lower ends. n / 2, the flow rates of the two channels of the fourth channel 19, which is connected to the outlet 8, are each Q. d / 2. The heat source of the electronic component is arranged at the right end of the flexible heat sink 2 and is attached to the wall of the flexible heat sink 2. The generated heat is transferred to the cooling medium in the channel through the thin film wall. The flow of the cooling medium transfers the heat to other parts of the channel. At this time, most of the heat is transferred through the flow rate Q. d The cooling medium is transferred towards the outlet 8 of the flow channel.

[0079] like Figure 10 As shown, when the piezoelectric vibrator 11 moves downward, the volume of the pump chamber 15 decreases, and the cooling medium is discharged from the pump chamber 15 through the outlet buffer chamber 10, the outlet cone tube 14, the inlet buffer chamber 12, and the inlet cone tube 16, respectively, from the pump outlet 3 and the pump inlet 4. This process is called the discharge process. At this time, the flow in the outlet cone tube 14 is in the diffusion direction, the flow resistance is relatively small, and the flow rate is large, which is Q. d The flow inside the inlet tapered tube 16 is in a contraction direction, resulting in relatively high flow resistance and a small flow rate, which is Q. n That is, the flow rate discharged from pump outlet 3 is greater than the flow rate discharged from pump inlet 4 during the discharge process, and the difference is Q. d - Q n .

[0080] like Figure 11 As shown, during the discharge process, the cooling medium in the flexible heat sink 2 channel is drawn in from the flow channel inlet 7 connected to the pump outlet 3 and the flow channel outlet 8 connected to the pump inlet 4, with flow rates of Q respectively.d and Q n The first flow channel 17, which is connected to the flow channel inlet 7, has a flow rate of Q at both its upper and lower ends. d / 2, the flow rates of the two channels of the fourth channel 19, which is connected to the outlet 8, are each Q. n / 2. At this point, most of the heat passes through a flow rate of Q. n The cooling medium is transferred towards the inlet 7 of the flow channel.

[0081] During the suction and discharge processes, the flow channel inside the flexible heat sink undergoes slight deformation. The change in volume of the flow channel caused by the deformation is equal to the change in volume of the pump chamber 15 of the valveless piezoelectric pump 1. The change in volume is very small, less than 0.001 ml.

[0082] In summary, the intake and exhaust processes constitute a complete vibration cycle. The volume change of pump chamber 11 is the same during both the intake and exhaust processes, both being Q. d + Q n The flow rate of valveless piezoelectric pump 1 in one cycle is Q. d - Q n The direction is from pump inlet 4 to pump outlet 3, and the flow rate of flexible heat sink 2 in one cycle is also Q. d - Q n. The flow direction is from the inlet 7 to the outlet 8 of the flow channel. The flow of the cooling medium transfers the heat generated by the electronic components at the heat source to the entire flow channel, realizing liquid cooling heat dissipation. The flow of the cooling medium in the flow channel of the flexible heat sink 2 is a periodic oscillating flow. Compared with steady-state flow, the oscillating reciprocating high-speed flow in this embodiment of the invention can enhance the turbulence of the cooling medium, strengthen the heat exchange between the fluid and the wall, and improve the heat exchange efficiency.

[0083] The valveless piezoelectric pump 1 of this invention has no movable valve plate structure. It utilizes the different flow resistances of the tapered tube in the diffusion and contraction flow directions to achieve directional delivery of the cooling medium, effectively eliminating the risk of valve plate fatigue failure. At the same time, by having a lower depth in the central region of the pump cavity than the surrounding region, combined with a raised plane, the volumetric compression ratio and bubble tolerance of the pump cavity are effectively improved. Compared with the unidirectional pulsating flow of a valved piezoelectric pump, the reciprocating oscillating flow of the valveless piezoelectric pump 1 can increase the instability of the fluid, enhance the degree of turbulence, and disrupt the thermal boundary layer, thereby enhancing the heat transfer between the fluid and the wall.

[0084] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0085] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A heat dissipation device integrating a valveless piezoelectric pump, characterized in that, It includes at least one valveless piezoelectric pump (1) and a flexible heat sink (2); The valveless piezoelectric pump (1) has a pump body (13), a pump cover (9) and a piezoelectric vibrator (11). The pump body (13) is provided with a pump chamber (15), a pump inlet (4), a pump outlet (3), an inlet cone (16) and an outlet cone (14). The inlet cone (16) is connected to the pump inlet (4) and the pump chamber (15) respectively. The outlet cone (14) is connected to the pump chamber (15) and the pump outlet (3) respectively. The pump cover (9) covers the pump body (13) and seals the pump chamber (15), the inlet cone (16) and the outlet cone (14) of the pump body (13). The piezoelectric vibrator (11) is fixed below the pump cover (9). The depth of the central region of the pump chamber (15) is lower than the depth of the peripheral region of the pump chamber (15). The flexible heat sink (2) has a flow channel inside, and the inlet (7) and outlet (8) of the flow channel are both located at one end of the flexible heat sink (2); The valveless piezoelectric pump (1) is attached and fixed to one end of the flexible heat sink (2). The inlet (7) and outlet (8) of the flow channel are connected to the pump outlet (3) and pump inlet (4) of the valveless piezoelectric pump (1) respectively, forming a circulating cooling path.

2. The heat dissipation device for the integrated valveless piezoelectric pump according to claim 1, characterized in that, The pump body (13) is also provided with an inlet buffer chamber (12) and an outlet buffer chamber (10). The inlet cone (16) and outlet cone (14) have the same structure and are arranged coaxially and are equidistant from the center of the pump chamber (15). The narrow end of the inlet cone (16) is connected to one end of the inlet buffer chamber (12), and the wide end is connected to the pump chamber (15). The narrow end of the outlet cone (14) is connected to the pump chamber (15), and the wide end is connected to one end of the outlet buffer chamber (10). The other end of the inlet buffer chamber (12) is connected to the pump inlet (4), and the other end of the outlet buffer chamber (10) is connected to the pump outlet (3).

3. The heat dissipation device for the integrated valveless piezoelectric pump according to claim 1, characterized in that, The bottom of the central region of the pump chamber (15) is provided with a raised plane, and the distance between the raised plane and the top of the pump chamber (15) is less than the distance between the bottom of the peripheral region of the pump chamber (15) and the top of the pump chamber (15).

4. The heat dissipation device for the integrated valveless piezoelectric pump according to claim 3, characterized in that, The depth ratio of the central region of the pump chamber (15) to the depth of the surrounding region is 0.1 to 0.

4.

5. The heat dissipation device for the integrated valveless piezoelectric pump according to claim 2, characterized in that, The length of the inlet cone (16) and outlet cone (14) is 0.8~4mm, the cone angle is 5°~15°, the depth is 0.08~0.2mm, the minimum cross-sectional width is 0.08~0.4mm, and the radius of the narrow end fillet is 0.08~0.4mm.

6. The heat dissipation device for the integrated valveless piezoelectric pump according to claim 1, characterized in that, The flexible heat dissipation plate (2) includes an upper layer, a middle layer and a lower layer in the thickness direction. The flow channel is located in the middle layer and the cooling medium is sealed in the middle layer flow channel through the upper layer and the lower layer. The flow channel depth is 0.1~0.5mm.

7. The heat dissipation device for the integrated valveless piezoelectric pump according to claim 6, characterized in that, The upper, middle and lower layers of the flexible heat sink (2) are all thin film materials, and the thin film materials are one or more of LCP, COP, EVA, carbon fiber, glass fiber cloth or FCCL materials.

8. The heat dissipation device for the integrated valveless piezoelectric pump according to claim 1, characterized in that, The flow channels within the flexible heat sink (2) include a first flow channel (17), a second flow channel (18), a third flow channel (20), and a fourth flow channel (19). The first flow channel (17) is connected to the flow channel inlet (7), the left end of the second flow channel (18) is connected to the upper end of the first flow channel (17), and the left end of the third flow channel (20) is connected to the lower end of the first flow channel (17). The fourth flow channel (19) is connected to the flow channel outlet (8), the upper end of the fourth flow channel (19) is connected to the right end of the second flow channel (18), and the lower end of the fourth flow channel (19) is connected to the right end of the third flow channel (20).

9. The heat dissipation device for the integrated valveless piezoelectric pump according to claim 8, characterized in that, The second flow channel (18) and the third flow channel (20) are both dual-flow parallel structures.

10. The heat dissipation device for the integrated valveless piezoelectric pump according to claim 1, characterized in that, The flexible heat dissipation plate (2) is provided with a liquid filling port (5) and a liquid outlet (6).

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