CN110798965B

CN110798965B - Controllable active fluid heat dissipation system of electronic component integrated on PCB

Info

Publication number: CN110798965B
Application number: CN201911108006.XA
Authority: CN
Inventors: 王代华; 彭芸浩
Original assignee: Chongqing University
Current assignee: Chongqing University
Priority date: 2019-11-13
Filing date: 2019-11-13
Publication date: 2022-10-14
Anticipated expiration: 2039-11-13
Also published as: CN110798965A

Abstract

The invention discloses a controllable active fluid cooling system of an electronic component integrated on a PCB (printed circuit board), which comprises a PCB substrate, an active fluid control device, a cooling device and a fluid cooling device, wherein the active fluid control device, the cooling device and the fluid cooling device are sequentially connected through a flow channel to form a closed loop, so that the self-circulation of liquid is formed. The active fluid control device is a piezoelectric actuating fluid pump integrated on the PCB substrate and controls the flow speed, flow and direction of fluid flowing in the heat dissipation system; the heat dissipation device is a micro-channel heat sink integrated on the PCB; the heat dissipation devices are arranged in one, two or more than one, and when the two or more than one heat dissipation devices are arranged, the heat dissipation devices are connected in parallel or in series between the active fluid control device and the piezoelectric actuating fluid pump; the liquid cooling device comprises a liquid storage tank integrated on the PCB and a heat dissipation fin or a refrigerating fin arranged above the liquid storage tank. The system is suitable for being integrated on a PCB (printed circuit board), can precisely control the flow rate, the flow speed and the flow direction of fluid, and achieves the purpose of thermal management of high-power high-heat-flow-density electronic components.

Description

Controllable active fluid heat dissipation system of electronic component integrated on PCB

Technical Field

The invention belongs to the technical field of controllable microfluid thermal management, and particularly relates to an integrated technology of an active fluid heat dissipation system on a PCB.

Background

The heat management problem of the high-power high-heat-flux-density electronic component (chip) is the core of the development of the future electronic device and is the key for restricting the development of the electronic device (chip). With the gradual failure of moore's law and the appearance of 3D integrated electronic devices (chips), the electronic devices (chips) are continuously developed towards miniaturization and high power density, and the power consumption and heat dissipation problems are more and more prominent while the performance is higher and higher. Thermal management of electronic devices (chips) has become a key technology to ensure product performance and lifetime.

Since 20 years after Tuckerman and Peace of Stanford university reported that a micro-channel is used as a tool for the first time and a novel heat dissipation method for conducting heat to a chip by means of convection heat transfer of liquid is adopted, the development of micro-channel heat sinks is extremely slow, and the heat management problem of electronic devices is more and more prominent until the 21 st century, along with the rapid development of high-power integrated circuits, the micro-channel heat sinks are used as a high-efficiency integrated chip heat dissipation means and get wide attention of scientists of various countries again. The overall size of the micro-channel heat sink is millimeter to centimeter level, and the size of the internal channel is micron level, so that the micro-channel heat sink has extremely high specific surface area and excellent heat conductivity. However, at present, the micro-channel heat sink heat dissipation system generally adopts an external fluid pump for driving, and needs to additionally configure a power line for driving the fluid pump and a pipeline for conveying liquid, so that the integration level of the whole system is low, and the pipeline has large pressure loss, which causes the reduction of the driving force and the control capability of the fluid pump, so that most of the micro-channel heat sink-based chip heat dissipation devices have relatively large volumes and cannot be efficiently integrated on the chip. The chinese patent application 200810069378.1 proposes a fluid pump with active precise control capability, which can achieve lower flow and extremely high control precision, but does not disclose a high-efficiency integration technology of the fluid pump with a PCB substrate and a micro-channel heat sink.

Because no effective scheme is provided by various scholars on how to integrate the fluid pump with the micro-channel heat sink and other components, the mainstream fluid heat dissipation system has the problems of weak control capability and low integration degree. Therefore, a new breakthrough needs to be made in the structure and integration principle of the fluid heat dissipation system.

Disclosure of Invention

The invention aims to provide an electronic component controllable active fluid heat dissipation system integrated on a PCB (printed circuit board), which overcomes the integration difficulty of each component of the fluid heat dissipation system, so that the active fluid heat dissipation system has the characteristics of compact structure, convenience in processing and high flexibility, can actively carry out heat management on high-power high-heat-flow-density electronic components, and improves the control capability of the fluid heat dissipation system and the integration degree of the system.

The technical scheme of the invention is as follows:

the invention provides a controllable active fluid cooling system of an electronic component integrated on a PCB (printed circuit board), which comprises a PCB substrate, and an active fluid control device, a cooling device and a fluid cooling device integrated on the PCB substrate, wherein the active fluid control device, the cooling device and the fluid cooling device are sequentially connected through a flow channel to form a closed loop, so that the self-circulation of liquid is formed.

The active fluid control device is a piezoelectric actuating fluid pump integrated on a PCB substrate and controls the flow speed, flow and direction of fluid flowing in the heat dissipation system.

The heat dissipation device comprises a micro-channel heat sink integrated on the PCB, an electronic component which is welded above the micro-channel heat sink and needs heat dissipation, and a heat flow sensor positioned on the electronic component, and is used for detecting the heat flow density and transferring heat for the electronic component; the heat dissipation device is provided in one, two or more, and when two or more are provided, they are connected in parallel or in series between the active fluid control device and the fluid cooling device.

The liquid cooling device comprises a liquid storage tank integrated on the PCB and radiating fins or refrigerating fins arranged above the liquid storage tank, and is used for cooling the cooling liquid carrying heat of the electronic component, and the liquid cooling device is respectively connected with the radiating device and the piezoelectric actuating fluid pump through flow channels.

The active fluid control device, the heat dissipation device and the fluid cooling device of the system supplement each other, and the defects are not met. The active fluid control device plays a role in controlling the flow speed, flow and flow direction of fluid, and is a power source of the active fluid cooling system, which can be controlled by the whole electronic component, and drives the fluid in the whole system to move. The heat dissipation device mainly plays a role in heat flux density detection and heat management of high-power high-heat flux density electronic components, is a heat dissipation core device of a whole electronic component controllable active fluid heat dissipation system, can be provided with one, two or more heat dissipation points according to the number of required heat dissipation points, and cooling liquid is provided through an active fluid control device. The liquid cooling device plays a role in cooling the cooling liquid which takes away the heat of the high-power high-heat-flow-density electronic component through the heat dissipation device, is a post-processing device of the controllable active fluid heat dissipation system of the whole electronic component, and ensures that the controllable active fluid heat dissipation system of the electronic component can continuously work normally and efficiently.

Specifically, the piezoelectric actuation fluid pump comprises a pumping unit and at least two piezoelectric actuation fluid valves, wherein the pumping unit and the at least two piezoelectric actuation fluid valves are integrated on the PCB, the pumping unit is respectively connected with each piezoelectric actuation fluid valve through a flow channel, the piezoelectric actuation fluid valves are used as liquid inlet valves or liquid outlet valves according to requirements, and fluid flows into the pump cavity through the liquid inlet valves and finally flows out of the liquid outlet valves.

The pump action unit consists of a pump cavity wall processed by a PCB process and a piezoelectric single crystal actuator covering and fixed on the pump cavity wall.

The piezoelectric actuating fluid valve consists of a valve cavity wall, a valve port part and a piezoelectric single crystal actuator, wherein the valve cavity wall and the valve port part are processed by a PCB process, and the piezoelectric single crystal actuator covers and is fixed on the valve cavity wall and opens/closes the valve port. The top surface of the valve port part is higher than the valve ground to form a surface boundary in contact with the piezoelectric single crystal actuator, the piezoelectric single crystal actuator is welded on the PCB through the wall of the valve port and is attached to or separated from the surface boundary of the valve port part to form an opening/closing relation, and the valve port part is a liquid inlet/outlet of the fluid pump. When no voltage or negative voltage is applied, the bottom of the piezoelectric single crystal actuator is closely leaned against the surface boundary of the valve opening part, the liquid inlet/outlet is closed, liquid cannot flow into or out of the liquid inlet, and at the moment, even if the pump action unit works, the fluid pump does not work. Therefore, the piezoelectric actuation fluid pump is a normally-closed piezoelectric actuation fluid pump and has good flow stopping characteristics.

The PCB wiring terminal is welded on the PCB substrate and electrically connected with the piezoelectric single crystal actuator, and the piezoelectric single crystal actuator drives the pump action unit and the piezoelectric actuation fluid valve to orderly act to realize the pumping in and out of the fluid. The flow, velocity and direction of the fluid are precisely controlled. The driving voltage adopts multiple paths of input signals, each path of input signal respectively acts on the piezoelectric single crystal actuators of the liquid inlet valve, the liquid outlet valve and the pump action unit, the piezoelectric single crystal actuator of the liquid inlet valve is firstly applied with the driving voltage, the phase of the driving voltage acting on the piezoelectric single crystal actuator of the pump action unit lags behind the phase of the driving voltage acting on the piezoelectric single crystal actuator of the liquid inlet valve, the phase of the driving voltage acting on the piezoelectric single crystal actuator of the liquid outlet valve lags behind the phase of the driving voltage acting on the piezoelectric single crystal actuator of the pump action unit, and the flow, the flow speed, the flow direction and the back pressure of the piezoelectric actuating fluid pump are controlled by changing the amplitude, the frequency and the phase of the driving voltages acting on the piezoelectric single crystal actuators of the liquid inlet valve, the liquid outlet valve and the pump action unit.

Specifically, the pump cavity wall, the valve cavity wall and the central channel of the piezoelectric actuation fluid pump are welded on a PCB substrate after being processed by a PCB process, or are directly processed and formed on the PCB substrate.

The pump cavity wall and the valve cavity wall which are welded on the PCB substrate after being processed by the PCB process are annular parts, the upper end face and the lower end face of each annular part are respectively provided with a copper-clad layer, one end face of each annular part is welded on a copper-clad bonding pad on the PCB substrate, and the other end face of each annular part is welded with a piezoelectric single crystal actuator, so that the pump cavity and the valve cavity are formed.

The pump cavity wall and the valve cavity wall which are directly processed and formed on the PCB substrate are formed by processing grooves downwards on the PCB substrate by using a PCB process, or formed by plating a copper-clad layer on the PCB substrate by using the PCB process; the structure can effectively improve the pump cavity compression ratio of the piezoelectric actuating fluid pump and improve the flow of the piezoelectric actuating fluid pump.

The valve opening part is a cylinder or a circular truncated cone, a central through hole is processed in the center of the cylinder or the circular truncated cone to serve as a liquid inlet/outlet channel, the valve opening part is welded on a copper-clad bonding pad on a PCB substrate after being processed by a PCB process or is directly processed on the PCB substrate, the valve opening part is coaxially communicated with the through hole on the PCB substrate, and the surface boundary of the valve opening part is matched with the piezoelectric single crystal actuator to form an opening/closing state.

The pump action unit is characterized in that the pump cavity wall of the pump action unit and the valve cavity wall of the piezoelectric actuating fluid valve are both provided with notches communicated outwards and connected through a flow channel, and the flow channel is welded on a PCB substrate after being processed through a PCB process or is directly processed and formed on the PCB substrate.

At least one base film layer is added below a substrate of the piezoelectric single crystal actuator, and the material, thickness, diameter and the like of each layer of structure are changed according to specific workplaces, so that the parameters of the piezoelectric single crystal actuator such as flexibility, natural frequency and the like are changed.

The micro-channel heat sink of the heat dissipation device is of a micro-channel structure, the shape of the channel can be flexibly selected according to different specific heat dissipation conditions and application scenes, and a rectangular structure, a wavy structure, a columnar structure or a sparse-dense-sparse structure can be selected.

In the invention, the heat dissipation device and the liquid cooling device which are arranged on the PCB substrate can be flexibly arranged at any position of the front side and the back side of the PCB substrate according to different specific heat dissipation conditions and application scenes; the micro-channel heat sink and the liquid storage tank structure can be processed by adopting a PCB process and welded on a PCB substrate; or directly slotting on the PCB substrate to form a micro-channel heat sink and liquid storage tank structure; the copper layer of the PCB substrate can be subjected to copper deposition treatment by adopting a PCB process so as to be higher than the substrate, thereby forming a micro-channel heat sink and liquid storage tank structure.

The pins of the electronic components are welded on copper-clad bonding pads processed at corresponding positions on the PCB substrate, so that the bottoms of the electronic components are positioned above the micro-channel heat sink and form gapless joint contact with the top of the micro-channel heat sink.

When the heat dissipation system works, the heat flow sensor arranged above the high-power high-heat-flow-density electronic component reads out the heat flow density of the electronic component in real time and makes a judgment. When the heat flux density is higher than a set value, a signal is sent out at the moment to enable the active fluid control device to start working, and a plurality of paths of electric signals are input to a piezoelectric single crystal actuator of a piezoelectric fluid pump of the active fluid control device to enable the piezoelectric fluid pump to pump liquid. The liquid conveys the cooling liquid to the micro-channel heat sink through a flow channel connecting the piezoelectric fluid pump and the micro-channel heat sink, carries out heat convection on electronic components needing heat dissipation, conveys the heat-absorbed cooling liquid to the liquid storage tank through the flow channel connecting the micro-channel heat sink and the liquid storage tank, cools the cooling liquid again through the heat dissipation fins or the refrigerating fins arranged above the liquid storage tank, conveys the cooled cooling liquid to the piezoelectric fluid pump through the flow channel connecting the liquid storage tank and the piezoelectric fluid pump, and enters the next heat dissipation cycle. The heat flow sensor reads the heat flow density of the electronic component in real time, and controls the active fluid control device to control the flow speed, flow and flow direction of the cooling liquid, so that the purpose of heat management of the high-power high-heat-flow-density electronic component is achieved.

The invention has the following advantages:

1. the active fluid control device, the heat dissipation device and the fluid cooling device are integrated on the PCB substrate through the PCB process, so that the integration degree of the fluid heat dissipation system is improved.

2. The active fluid control device of the invention is mainly composed of a piezoelectric fluid pump, the fluid pump adopts a fluid valve with a surface boundary higher than the bottom surface of the valve to form a liquid inlet valve and a liquid outlet valve, because a general valve port is not higher than the bottom surface of the valve but is flush with the bottom surface of the valve, the invention adopts a circular ring with a surface boundary to form a valve port part, the surface boundary is higher than the bottom surface of the valve and is matched with a piezoelectric single crystal actuator, so that the valve has extremely high flow stopping property and capability of actively controlling fluid when not working.

3. The piezoelectric fluid pump in the active fluid control device realizes bidirectional pumping by controlling the fluid valve, changes the frequency, amplitude and phase relation of control signals of the piezoelectric single crystal actuator acting on the driving fluid valve and the pumping action unit, can change the states of the flow rate, the flow speed, the flow direction and the like of the micro-fluid pump, is matched with a heat flow sensor arranged above a high-power high-heat-flow-density electronic component for use, and can efficiently and accurately carry out heat management on the electronic component.

4. The heat dissipation devices can be arranged in a plurality according to the needs of heat dissipation points, and the piezoelectric fluid pump preferably adopts a piezoelectric single crystal actuator structure, so that the pump flow of the piezoelectric fluid pump can be improved.

5. The PCB provided by the invention has the advantages that the controllable active fluid heat dissipation system of the electronic component integrated on the PCB is convenient to process, compact in structure and changeable in form, and can meet the heat dissipation requirements of high-power high-heat-flow-density electronic components in different scenes and under different requirements.

Drawings

Fig. 1 is a schematic diagram illustrating a structural principle of a controllable active fluid heat dissipation system with electronic components integrated on a PCB according to an embodiment of the present invention;

FIG. 1 (base:Sub>A) isbase:Sub>A cross-sectional view A-A of one configuration of the active fluid control device of FIG. 1;

fig. 2 is a top view of a PCB substrate with integrated electronic components and controllable active fluid heat dissipation system according to an embodiment of the present invention;

fig. 2 (a) is a three-dimensional structural view of the micro flow channel heat sink of the rectangular structure in fig. 2;

FIG. 3 is a top view of a PCB substrate with integrated electronic components on the PCB for controlling a second implementation of an active fluid heat dissipation system in accordance with the first embodiment of the present invention;

FIG. 3 (a) is a three-dimensional structure diagram of the micro flow channel heat sink of the wavy structure in FIG. 3;

FIG. 4 is a top view of a PCB substrate with a third exemplary structure for an integrated electronic component and controllable active fluid heat dissipation system according to one embodiment of the present invention;

FIG. 4 (a) is a three-dimensional structural view of the micro flow channel heat sink of a cylindrical structure in FIG. 4;

fig. 5 is a top view of a PCB substrate with a fourth exemplary structure for an integrated electronic component on PCB to control an active fluid heat dissipation system according to an embodiment of the present invention;

FIG. 5 (a) is a three-dimensional structural view of the micro flow channel heat sink of the sparse-dense-sparse structure of FIG. 5;

fig. 6 is a bottom view of a PCB substrate with integrated electronic components on the PCB controlling an implementation structure of an active fluid heat dissipation system according to an embodiment of the present invention;

fig. 7 is a top view of an exemplary structural assembly of an integrated electronic component on PCB controllable active fluid heat dissipation system according to an embodiment of the present invention;

fig. 8 is a bottom view of an exemplary structural assembly of an integrated electronic component on PCB controllable active fluid heat dissipation system in accordance with one embodiment of the present invention;

fig. 9 is a schematic structural diagram of a controllable active fluid heat dissipation system with electronic components integrated on a PCB according to the second embodiment of the present invention;

FIG. 9 (base:Sub>A) isbase:Sub>A cross-sectional view A-A of one configuration of the active fluid control device of FIG. 9;

fig. 10 is a top view of a PCB substrate with integrated electronic components on the PCB controlling an implementation structure of an active fluid heat dissipation system according to a second embodiment of the present invention;

fig. 11 is a top view of a PCB substrate with integrated electronic components on the PCB controlling a second implementation of an active fluid heat dissipation system in accordance with a second embodiment of the present invention;

figure 12 is a top view of a PCB substrate with integrated electronic components on the PCB controlling an active fluid heat dissipation system according to a third embodiment of the present invention;

figure 13 is a top view of a PCB substrate with fourth exemplary implementation of a controllable active fluid heat dissipation system with electronic components integrated on the PCB according to the second embodiment of the present invention;

fig. 14 is a bottom view of a PCB substrate with integrated electronic components on the PCB controlling an implementation of an active fluid heat dissipation system in accordance with a second embodiment of the present invention;

fig. 15 is a top view of an exemplary structural assembly of a controllable active fluid heat dissipation system for electronic components integrated on a PCB according to the second embodiment of the present invention;

fig. 16 is a bottom view of an exemplary assembly of a controllable active fluid heat dissipation system with electronic components integrated on a PCB according to the second embodiment of the present invention.

FIG. 17 isbase:Sub>A cross-sectional view A-A of the active fluid control device of FIGS. 1 and 9 inbase:Sub>A second configuration;

fig. 18 isbase:Sub>A cross-sectional viewbase:Sub>A-base:Sub>A of the active fluid control device of fig. 1 and 9 inbase:Sub>A third configuration.

Detailed Description

The invention is described in detail below with reference to the following figures and examples:

the first embodiment is as follows:

fig. 1 is a schematic structural diagram of a controllable active fluid heat dissipation system with electronic components integrated on a PCB according to this embodiment. The active fluid heat dissipation system integrated on the PCB is composed of the active fluid control device 20 soldered on the PCB substrate 1, the heat dissipation device 25 and the fluid cooling device 27. The active fluid control device 20 is mainly formed by a piezoelectric actuating fluid pump, which is formed by a cylindrical pumping unit 10 and two piezoelectric

actuating fluid valves

4, 15 with valve openings of the

circular ring boundaries

3, 13, and the cylindrical pumping unit 10 is connected with the two piezoelectric

actuating fluid valves

4, 15 with the circular ring boundaries through

flow channels

8, 16 on both sides. The cylindrical pump action unit 10 is composed of a pump cavity wall 9 of the pump action unit processed by a PCB process and a disc-shaped piezoelectric single crystal actuator 11 fixed on the pump cavity wall 9, and the disc-shaped piezoelectric single crystal actuator 11 is installed on the PCB substrate 1 through the pump cavity wall 9 processed by the PCB process to form a cylindrical pump cavity 12. The piezoelectric actuating fluid valve 4 (or 15) with the circular ring boundary is composed of a valve cavity wall 2 (or 14) of the fluid valve processed by a PCB process, a circular ring boundary 3 (or 13) processed by the PCB process and a disc-shaped piezoelectric single crystal actuator 5 (or 19) fixed on the valve cavity wall 2 (or 14), the circular ring boundary 3 (or 13) is processed in the center of a circular cylindrical valve cavity 6 (or 17) on a PCB substrate 1 by the PCB process, and when the disc-shaped piezoelectric single crystal actuator 5 (or 19) is welded on the PCB through the valve cavity wall 2 (or 14) processed by the PCB process, a microfluidic boundary is naturally formed with the circular ring boundary 3 (or 13). The through hole of the circular ring surface boundary and the through hole of the PCB substrate coaxial with the circular ring surface boundary form a liquid inlet/outlet channel 7 (or 18) of the fluid pump. When no driving voltage acts on the disc-shaped piezoelectric

single crystal actuators

5 and 19, the bottoms of the disc-shaped piezoelectric

single crystal actuators

5 and 19 constituting the

fluid valves

4 and 15 are closely abutted to the top ends of the

annular surface boundaries

3 and 13, the annular

cylindrical valve cavities

6 and 17 are separated from the liquid inlet 7 (or 18) and the liquid outlet 18 (or 7), the liquid inlet 7 (or 18) and the liquid outlet 18 (or 7) are closed, liquid cannot flow into the liquid outlet 18 (or 7) from the liquid inlet 7 (or 18), and at this time, even if the pumping unit 10 works, the fluid pump does not work. The cylindrical pumping unit 10 and the piezoelectric

actuating fluid valves

4 and 15 are soldered on the PCB substrate 1 to form an active fluid control device 20.

The active fluid heat dissipation system with controllable electronic components integrated on the PCB is composed of a heat dissipation device 25 welded on a PCB substrate 1, and mainly comprises a flow channel 21 connected with an active fluid control device 20, a micro-channel heat sink 22, a high-power high-heat-flux electronic component 23 and a heat flow sensor 24. The cooling liquid sent by the active fluid control device 20 is sent to the micro-channel heat sink 22 through the channel 21, and dissipates heat of the high-power high-heat-flux electronic component 23, and then the cooling liquid with heat of the high-power high-heat-flux electronic component 23 is sent to the fluid cooling device 27 through the channel 26 connecting the heat dissipation device 25 and the fluid cooling device 27 to cool and recycle the cooling liquid. The heat flow sensor 24 detects the heat flow density of the high-power high-heat-flow-density electronic component 23 in real time, and controls the working state of the active fluid control device 20 through feedback control, so as to achieve the purpose of controlling the flow rate, flow and flow direction of the cooling fluid, and finally achieve the purpose of heat management of the high-power high-heat-flow-density electronic component 23.

The fluid cooling device 27 is mainly composed of a liquid storage tank 28 and a heat radiation fin or a refrigerating sheet 29, wherein the function of the liquid storage tank 28 is to enable an electronic component integrated on the whole PCB to control an active fluid heat radiation system to form a closed system to form self circulation of liquid; and secondly, a larger liquid buffer space is reserved, so that the cooling liquid which flows out of the heat dissipation device 25 and takes away the heat of the high-power high-heat-flux-density electronic component 23 has enough space and time to cool again, and preparation is made for the next heat dissipation cycle. The heat sink fins or cooling fins 29 disposed above the liquid reservoir 28 serve to cool the cooling liquid flowing out of the heat sink 25 and carrying away the heat of the high-power high-heat-flux electronic component 23 again. The entire liquid cooling device 27 functions to ensure that the active fluid heat dissipation system can continue to operate normally and efficiently under the control of the electronic components integrated on the PCB.

Fig. 1 (base:Sub>A) isbase:Sub>A sectional viewbase:Sub>A-base:Sub>A ofbase:Sub>A structure of the active fluid control device in fig. 1, in which the structure of the active fluid control device is formed by directly processingbase:Sub>A groove downward onbase:Sub>A PCB substrate by usingbase:Sub>A PCB process, and the active fluid control device of the structure has reduced power consumption and flow rate, and is suitable for being used in an occasion with low requirement on the flow rate but strict requirement on the working power consumption.

Fig. 17 isbase:Sub>A sectional viewbase:Sub>A-base:Sub>A of the second structure of the active fluid control device in fig. 1, in which the structure of the active fluid control device is directly formed by processingbase:Sub>A groove downward onbase:Sub>A PCB substrate by usingbase:Sub>A PCB process, wherein the pump cavity wall isbase:Sub>A cylindrical cavity which is directly processed on the PCB substrate and is penetrated from top to bottom, the upper and lower surfaces of the cylindrical cavity are covered and fixed with piezoelectric single crystal actuators, and the piezoelectric single crystal actuator 52 isbase:Sub>A second piezoelectric single crystal actuator of the cylindrical pump cavity 12.

Fig. 18 isbase:Sub>A sectional viewbase:Sub>A-base:Sub>A of the active fluid control device of fig. 1 inbase:Sub>A third configuration in which the active fluid control device is formed by plating upbase:Sub>A copper cladding directly onbase:Sub>A PCB substrate usingbase:Sub>A PCB process, wherein the pump chamber 12 is connected to the

valve chamber

6, 17 through the

flow channels

8, 16, 53, 54, which is effective to increase the pump chamber compression ratio of the piezo-actuated fluid pump and increase the flow rate of the piezo-actuated fluid pump.

Fig. 2 is a top view of a PCB substrate of a first specific implementation structure of the PCB substrate of the system for controlling active fluid heat dissipation integrated on a PCB according to the present invention, which is designed according to the structural principle of fig. 1. The reservoir 28 is connected to the microchannel heat sink 22 and the valve chamber 17 via the

channels

26, 30, respectively. The pump chamber 12 is connected with the

valve chambers

6 and 17 through the

flow channels

8 and 16, wherein the micro-channel heat sink 22 is a rectangular micro-channel heat sink, and the specific structure is shown in fig. 2 (a).

Fig. 3 is a top view of a PCB substrate of a second specific implementation structure of the controllable active fluid heat dissipation system with electronic components integrated on the PCB according to the structural principle of fig. 1 in this embodiment. The reservoir 28 is connected to the microchannel heat sink 43 and the valve chamber 17 via the

channels

26, 30, respectively. The pump chamber 12 is connected to the

valve chambers

6, 17 via the

channels

8, 16, wherein the microchannel heat sink 43 is a corrugated microchannel heat sink, see fig. 3 (a).

Fig. 4 is a top view of a PCB substrate of a third specific implementation structure of the controllable active fluid heat dissipation system with electronic components integrated on the PCB according to the structural principle of fig. 1 in this embodiment. The reservoir 28 is connected to the microchannel heat sink 44 and the valve chamber 17 via the

channels

26, 30, respectively. The pump chamber 12 is connected to the

valve chambers

6, 17 via the

channels

8, 16, wherein the microchannel heat sink 44 is a columnar structure microchannel heat sink, see fig. 4 (a).

Fig. 5 is a top view of a PCB substrate of a fourth specific implementation structure of the controllable active fluid heat dissipation system with electronic components integrated on the PCB according to the structural principle of fig. 1 in this embodiment. The reservoir 28 is connected to the microchannel heat sink 45 and the valve chamber 17 via the

channels

26, 30, respectively. The pump chamber 12 is connected with the

valve chambers

6, 17 through the

channels

8, 16, wherein the micro-channel heat sink 45 is a micro-channel heat sink with a sparse-dense-sparse structure, and the specific structure is shown in fig. 5 (a).

Fig. 6 is a bottom view of a PCB substrate of an implementation structure of the PCB-integrated electronic component controllable active fluid heat dissipation system according to the structural principle of fig. 1 in this embodiment. The

valve chambers

6, 17 are connected to the pump chamber 12 via the

flow channels

8, 16.

Fig. 7 is a top view of an exemplary structural assembly of the controllable active fluid heat dissipation system with electronic components integrated on a PCB according to the principle of fig. 1. The flow path cover

plates

31, 33, 34, 36 are attached to the

flow paths

26, 8, 16, 30. The disc-shaped piezoelectric single crystal actuator 11 is mounted on the pump chamber wall 9. A microchannel heat sink cover plate 32 is mounted over the microchannels 22. A reservoir cover 35 is mounted on the reservoir 28.

Fig. 8 is a bottom view of an exemplary structural assembly of the PCB-integrated electronic component controllable active fluid heat dissipation system according to the structural principle of fig. 1. Disc-shaped piezoelectric

single crystal actuators

5 and 19 are attached to the

valve chamber walls

2 and 14.

The second embodiment is as follows:

fig. 9 is a schematic structural diagram of another PCB-integrated electronic component controllable active fluid heat dissipation system according to this embodiment. The controllable active fluid heat dissipation system for the electronic components integrated on the PCB mainly aims at the requirement that a plurality of high-power high-heat-flux electronic components which need to dissipate heat simultaneously are arranged on a PCB substrate to conduct heat management. The active fluid heat dissipation system with integrated electronic components and control on the PCB is composed of an active fluid control device 20, a first heat dissipation device 25, a second heat dissipation device 32 and a fluid cooling device 27 which are integrated on a PCB substrate 1.

The active fluid control device 20 is formed mainly by a piezo-actuated fluid pump, which is formed by a cylindrical pumping unit 10 and two piezo-actuated

fluid valves

4, 15 with

toroidal boundaries

3, 13, and the cylindrical pumping unit 10 is connected to the two piezo-actuated

fluid valves

4, 15 with toroidal boundaries via

flow channels

8, 16 on both sides. The cylindrical pumping action unit 10 is composed of a pump cavity wall 9 of the pumping action unit processed by a PCB process and a disc-shaped piezoelectric single crystal actuator 11 fixed on the pump cavity wall 9, and the disc-shaped piezoelectric single crystal actuator 11 is installed on the PCB substrate 1 through the pump cavity wall 9 processed by the PCB process to form a cylindrical pump cavity 12. The piezoelectric actuating fluid valve 4 (or 15) with the circular ring boundary is composed of a valve cavity wall 2 (or 14) of the fluid valve processed by a PCB process, a circular ring boundary 3 (or 13) processed by the PCB process and a disc-shaped piezoelectric single crystal actuator 5 (or 19) fixed on the valve cavity wall 2 (or 14), the circular ring boundary 3 (or 13) is processed in the center of a circular cylindrical valve cavity 6 (or 17) on a PCB substrate 1 by the PCB process, and when the disc-shaped piezoelectric single crystal actuator 5 (or 19) is welded on the PCB through the valve cavity wall 2 (or 14) processed by the PCB process, a microfluidic boundary is naturally formed with the circular ring boundary 3 (or 13). The through hole of the circular ring surface boundary and the through hole of the PCB substrate coaxial with the circular ring surface boundary form a liquid inlet/outlet channel 7 (or 18) of the fluid pump. When no driving voltage acts on the disc-shaped piezoelectric

single crystal actuators

5 and 19, the bottoms of the disc-shaped piezoelectric

single crystal actuators

5 and 19 constituting the

fluid valves

4 and 15 are closely abutted to the top ends of the

annular surface boundaries

3 and 13, the annular

cylindrical valve cavities

actuating fluid valves

The first heat dissipation device 25 is mainly composed of a flow channel 21 connected with the active fluid control device 20, a micro-flow channel heat sink 22, a high-power high-heat-flux electronic component 23 and a heat-flux sensor 24. The cooling liquid sent by the active fluid control device 20 is sent to the micro-channel heat sink 22 through the channel 21, the high-power high-heat-flow-density electronic component 23 is subjected to heat dissipation, and then the cooling liquid with the heat of the high-power high-heat-flow-density electronic component 23 is sent to the fluid cooling device 27 through the channel 26 which is connected with the first heat dissipation device 25 and the fluid cooling device 27 to be cooled and recycled. The heat flow sensor 24 detects the heat flow density of the high-power high-heat-flow-density electronic component 23 in real time, and controls the working state of the active fluid control device 20 through feedback control, so that the purposes of controlling the flow speed, flow and flow direction of the cooling liquid are achieved, and finally the purpose of heat management of the high-power high-heat-flow-density electronic component 23 is achieved.

The second heat dissipation device 32 is mainly composed of a flow channel 21 connected with the active fluid control device 20, a micro-flow channel heat sink 34, a high-power high-heat-flow-density electronic component 33 and a heat-flow sensor 31. The cooling liquid sent by the active fluid control device 20 is sent to the micro-channel heat sink 34 through the channel 21, the high-power high-heat-flow-density electronic component 33 is subjected to heat dissipation, and then the cooling liquid with the heat of the high-power high-heat-flow-density electronic component 33 is sent to the fluid cooling device 27 through the channel 26 connecting the second heat dissipation device 32 and the fluid cooling device 27 to be cooled and recirculated. The heat flow sensor 31 detects the heat flow density of the high-power high-heat-flow-density electronic component 33 in real time, controls the working state of the active fluid control device 20 through feedback control, achieves the purpose of controlling the flow speed, flow and flow direction of the cooling liquid, and finally achieves the purpose of heat management of the high-power high-heat-flow-density electronic component 33.

The fluid cooling device 27 is mainly composed of a liquid storage tank 28 and a heat radiation fin or a refrigerating sheet 29, wherein the function of the liquid storage tank 28 is to enable an electronic component integrated on the whole PCB to control an active fluid heat radiation system to form a closed system to form self circulation of liquid; and secondly, a larger liquid buffer space is reserved, so that the cooling liquid which flows out of the heat dissipation device 25 and takes away the heat of the high-power high-heat-flow-density electronic component 23 has enough space and time to cool again to prepare for the next heat dissipation cycle. The heat dissipation fins or refrigeration fins 29 disposed above the liquid storage 28 function to cool the cooling liquid flowing out of the heat dissipation device 25 and carrying away the heat of the high-power high-heat-flux electronic component 23 again. The entire liquid cooling device 27 functions to ensure that the active fluid heat dissipation system can continue to operate normally and efficiently under the control of the electronic components integrated on the PCB.

The controllable active fluid cooling system of the electronic components integrated on the PCB can meet the requirement that a plurality of high-power high-heat-flux electronic components which need to be cooled simultaneously on a PCB substrate carry out heat management.

Fig. 9 (base:Sub>A) isbase:Sub>A cross-sectional viewbase:Sub>A-base:Sub>A of the active fluid control device in fig. 1, in which the active fluid control device is directly formed by processingbase:Sub>A groove downward onbase:Sub>A PCB substrate by usingbase:Sub>A PCB process, and the active fluid control device has reduced power consumption and flow rate, and is suitable for use in an application where the requirement for flow rate is low but the requirement for working power consumption is strict.

Fig. 18 isbase:Sub>A sectional viewbase:Sub>A-base:Sub>A of the active fluid control device of fig. 1 inbase:Sub>A third configuration in which the active fluid control device is formed by plating upbase:Sub>A copper layer directly onbase:Sub>A PCB substrate usingbase:Sub>A PCB process, wherein the pump chamber 12 is connected to the

valve chambers

6, 17 through the

flow channels

8, 16, 53, 54, which configuration is effective to increase the pump chamber compression ratio of the piezo-actuated fluid pump and increase the flow rate of the piezo-actuated fluid pump.

Fig. 10 is a top view of a PCB substrate of a first specific implementation structure of the controllable active fluid heat dissipation system with electronic components integrated on the PCB according to the structural principle of fig. 9. The pump chamber 12 is connected to the

valve chambers

6, 17 via the

flow channels

8, 16. The

micro-channel heat sinks

22 and 34 are respectively connected with the liquid storage tank 28 in the valve chamber 6 through the

channels

21 and 26. The reservoir 28 is connected to the valve chamber 17 by a flow passage 30. The

micro-channel heat sinks

22, 34 are rectangular-structured micro-channel heat sinks.

Fig. 11 is a top view of a PCB substrate of a second specific implementation structure of the controllable active fluid heat dissipation system with electronic components integrated on the PCB according to the structural principle of fig. 9. The pump chamber 12 is connected to the

valve chambers

6, 17 via the

flow channels

8, 16. The

micro-channel heat sinks

47 and 46 are respectively connected with the liquid storage tank 28 in the valve chamber 6 through the

channels

21 and 26. The reservoir 28 is connected to the valve chamber 17 by a flow passage 30. The micro flow

channel heat sinks

47 and 26 are wave-shaped micro flow channel heat sinks.

Fig. 12 is a top view of a PCB substrate of a third specific structure of an electronic component-controllable active fluid heat dissipation system integrated on a PCB according to the structural principle of fig. 9. The pump chamber 12 is connected to the

valve chambers

6, 17 via the

flow channels

8, 16. The

microchannel heat sinks

51 and 50 are connected with the liquid storage tank 28 in the valve chamber 6 through the

channels

21 and 26 respectively. The reservoir 28 is connected to the valve chamber 17 by a flow passage 30. The micro flow

channel heat sinks

51, 50 are columnar structure micro flow channel heat sinks.

Fig. 13 is a top view of a PCB substrate of a fourth specific implementation structure of the controllable active fluid heat dissipation system with electronic components integrated on the PCB according to the structural principle of fig. 9 in this embodiment. The pump chamber 12 is connected to the

valve chambers

6, 17 via the

flow channels

8, 16. The

micro-channel heat sinks

channels

49 and 48. The reservoir 28 is connected to the valve chamber 17 by a flow passage 30. The

micro-channel heat sinks

49, 48 are micro-channel heat sinks of a sparse-dense-sparse structure.

Fig. 14 is a bottom view of a PCB substrate of an implementation structure of a PCB-integrated electronic component controllable active fluid heat dissipation system according to the structural principle of fig. 9. The

valve chambers

6, 17 are connected to the pump chamber 12 via the

flow channels

8, 16. The liquid inlet/

outlet ports

7, 18 are connected to flow

passages

21, 30.

Fig. 15 is a top view of an exemplary structural assembly of the controllable active fluid heat dissipation system with electronic components integrated on a PCB according to the principles of the structure of fig. 9. The flow path cover

plates

37, 38, 39, 40, 43 are attached to the

flow paths

16, 30, 39, 21, 26. A reservoir cover 44 is mounted to the reservoir 28. Micro-channel heat

sink cover plates

41, 42 are mounted on the

micro-channel heat sinks

22, 34. The disc-shaped piezoelectric single crystal actuator 11 is mounted on the pump chamber wall 9.

Fig. 16 is a bottom view of an exemplary structural assembly of a PCB-integrated electronic component controllable active fluid heat dissipation system according to the structural principle of fig. 9. Disc-shaped piezoelectric

single crystal actuators

5 and 19 are attached to the

valve chamber walls

2 and 14.

The electrical assembly process flow of the system of each embodiment on the PCB substrate is as follows:

(a) Cleaning the surface of the fluid pump substrate by alcohol to remove dust and various pollutants on the bonding pad, so that the bonding pad has good welding characteristics;

(b) Welding a disc-shaped piezoelectric single crystal actuator on a welding disc of a pump chamber and a valve chamber;

(c) Welding the flow channel cover, the micro-flow channel heat sink cover and the liquid storage tank cover on the welding disc at corresponding positions;

(d) Arranging a high-power high-heat-flow-density electronic component needing heat dissipation above the micro-channel heat sink cover, and arranging a heat flow sensor above the electronic component;

(e) Placing the heat dissipation fins or the refrigeration sheets above the liquid storage tank cover;

and electrically connecting all devices needing to be electrically connected at corresponding positions of the PCB substrate to complete the integration of the active fluid heat dissipation system on the PCB substrate.

Claims

1. The controllable active fluid cooling system of electronic components integrated on PCB is characterized in that: the liquid self-circulation system comprises a PCB substrate, and an active fluid control device, a heat dissipation device and a fluid cooling device which are integrated on the PCB substrate, wherein the active fluid control device, the heat dissipation device and the fluid cooling device are sequentially connected through a flow channel to form a closed loop so as to form liquid self-circulation;

the active fluid control device is a piezoelectric actuating fluid pump integrated on the PCB substrate and controls the flow speed, flow and flow direction of fluid flowing in the heat dissipation system;

the heat dissipation device comprises a micro-channel heat sink integrated on the PCB, an electronic component which is welded above the micro-channel heat sink and needs heat dissipation, and a heat flow sensor positioned on the electronic component, and is used for detecting the heat flow density and transferring heat for the electronic component; the heat dissipation device is provided with one, two or more heat dissipation devices, and when two or more heat dissipation devices are provided, the two or more heat dissipation devices are connected in parallel or in series between the active fluid control device and the fluid cooling device;

the fluid cooling device is composed of a liquid storage tank integrated on the PCB and radiating fins or refrigerating fins arranged above the liquid storage tank, and is used for cooling the cooling liquid carrying heat of the electronic components;

the piezoelectric actuating fluid pump is composed of a pump action unit and two piezoelectric actuating fluid valves on a PCB, wherein the pump action unit is respectively connected with each piezoelectric actuating fluid valve through a flow channel, and the piezoelectric actuating fluid valves are used as liquid inlet valves or liquid outlet valves according to requirements;

the pump action unit consists of a pump cavity wall processed by a PCB process and a piezoelectric single crystal actuator which is covered and fixed on the pump cavity wall;

the piezoelectric actuating fluid valve consists of a valve cavity wall, a valve port part and a piezoelectric single crystal actuator, wherein the valve cavity wall and the valve port part are processed by a PCB (printed Circuit Board) process, and the piezoelectric single crystal actuator covers and is fixed on the valve cavity wall and opens/closes the valve port; the top surface of the valve port part is higher than the bottom of the valve to form a surface boundary contacted with the piezoelectric single crystal actuator, the piezoelectric single crystal actuator is welded on the PCB through the wall of the valve port and is attached to or separated from the surface boundary of the valve port part to form an opening/closing relation, and the valve port part is a liquid inlet/outlet of the fluid pump;

the PCB wiring terminal is welded on the PCB substrate and electrically connected with the piezoelectric single crystal actuator, and the piezoelectric single crystal actuator drives the pump action unit and the piezoelectric actuation fluid valve to orderly act to realize the accurate control function of the flow rate, the flow speed and the flow direction of the fluid;

the driving voltage adopts multiple paths of input signals, each path of input signal respectively acts on the piezoelectric single crystal actuator of the liquid inlet valve, the liquid outlet valve and the pump action unit, the piezoelectric single crystal actuator of the liquid inlet valve is firstly applied with the driving voltage, the phase of the driving voltage acting on the piezoelectric single crystal actuator of the pump action unit lags behind the phase of the driving voltage acting on the piezoelectric single crystal actuator of the liquid inlet valve, the phase of the driving voltage acting on the piezoelectric single crystal actuator of the liquid outlet valve lags behind the phase of the driving voltage acting on the piezoelectric single crystal actuator of the pump action unit, and the flow, the flow speed, the flow direction and the back pressure of the piezoelectric actuation fluid pump are controlled by changing the amplitude, the frequency and the phase of the driving voltage acting on the piezoelectric single crystal actuators of the liquid inlet valve, the liquid outlet valve and the pump action unit;

2. The PCB integrated electronic component controllable active fluid heat dissipation system of claim 1, wherein: the pump cavity wall, the valve cavity wall and the central channel of the piezoelectric actuating fluid pump are welded on a PCB substrate after being processed by a PCB process, or are directly processed and formed on the PCB substrate;

the pump cavity wall and the valve cavity wall which are welded on the PCB substrate after being processed by the PCB process are annular parts, the upper end face and the lower end face of each annular part are both fully copper-clad layers, one end face of each annular part is welded on a copper-clad bonding pad on the PCB substrate, and the other end face of each annular part is welded with a piezoelectric single crystal actuator, so that the pump cavity and the valve cavity are formed;

the pump cavity wall and the valve cavity wall which are directly processed and formed on the PCB substrate are formed by processing grooves downwards on the PCB substrate by using a PCB process, or formed by plating a copper-clad layer on the PCB substrate by using the PCB process.

3. The PCB integrated electronic component controllable active fluid heat dissipation system of claim 2, wherein: the pump cavity wall directly formed by processing on the PCB substrate is a cylindrical cavity which is directly processed on the PCB substrate and is communicated up and down, and the upper surface and the lower surface of the cylindrical cavity are both covered and fixed with the piezoelectric single crystal actuator.

4. The PCB integrated electronic component controllable active fluid heat dissipation system of claim 1, wherein: the pump action unit is characterized in that the pump cavity wall of the pump action unit and the valve cavity wall of the piezoelectric actuating fluid valve are both provided with notches communicated outwards and connected through a flow channel, and the flow channel is welded on a PCB substrate after being processed through a PCB process or is directly processed and formed on the PCB substrate.

5. The PCB integrated electronic component controllable active fluid heat dissipation system of claim 1, wherein: the piezoelectric single crystal actuator is formed by bonding piezoelectric ceramics and a substrate, the edge of the substrate of the piezoelectric single crystal actuator is welded and fixed on the wall of a valve cavity or the wall of a pump cavity to form a solid supporting edge structure, the cathode of the piezoelectric single crystal actuator is connected with a system power ground, and the anode of the piezoelectric single crystal actuator is connected with the anode of the system power.

6. The PCB integrated electronic component controllable active fluid heat dissipation system of claim 1, wherein: at least one base film layer is added below a substrate of the piezoelectric single crystal actuator, and the material, the thickness and the diameter of each layer of structure are changed according to specific work places, so that the flexibility and the natural frequency of the piezoelectric single crystal actuator are changed.

7. A PCB-integrated electronic component controllable active fluid heat dissipation system as recited in any one of claims 1-6, wherein: the micro-channel heat sink of the heat dissipation device is of a micro-channel structure, the shape of the channel is flexibly selected according to different specific heat dissipation conditions and application scenes, and the channel is of a rectangular structure, a wavy structure, a columnar structure or a sparse-dense-sparse structure.

8. A PCB-integrated electronic component controllable active fluid heat dissipation system as recited in any one of claims 1-6, wherein: the heat dissipation device and the fluid cooling device which are arranged on the PCB substrate are flexibly arranged at any position of the front surface and the back surface of the PCB substrate according to different specific heat dissipation conditions and application scenes; a micro-channel heat sink and a liquid storage tank structure are processed by adopting a PCB process and welded on a PCB substrate; or a micro-channel heat sink and a liquid storage tank structure are formed by directly slotting on the PCB substrate; or carrying out copper deposition treatment on the copper layer of the PCB substrate by adopting a PCB process to enable the copper layer to be higher than the substrate, and forming a micro-channel heat sink and liquid storage tank structure.

9. A PCB-integrated electronic component controllable active fluid heat dissipation system as recited in any one of claims 1-6, wherein: the pins of the electronic components are welded on copper-clad bonding pads processed at corresponding positions on the PCB substrate, so that the bottoms of the electronic components are positioned above the micro-channel heat sink and form gapless joint contact with the top of the micro-channel heat sink.