TWI455473B - Piezoelectric micro power generator - Google Patents

Description

Piezoelectric micro power generation device

The invention relates to a piezoelectric micro-electric power generation device, in particular to a piezoelectric micro-generator using a steam air flow generated by heating of a working fluid in a hollow tube as a power source to drive a piezoelectric element to generate vibration and then generate electricity. The overall size is quite flexible, and it can not only solve the heat dissipation problem of today's miniaturized electronic products, but also achieve the power generation efficiency and further improve the energy utilization efficiency of the piezoelectric micro-power generation device.

According to the circuit in the electronic device, some processing operations are performed by using electric power, and thus waste heat is generated. However, the waste heat is generally only emitted to the environment and is not used; the current MEMS are mostly used for miniature sensors ( For example, pressure gauges, gyroscopes, accelerometers, gas sensors, infrared thermometers, etc.) and actuators (such as micromotors, micro-pulls, and micro-switches), and face micro-energy supply during system miniaturization. The problem is that the portable wireless sensors and portable electronic devices in the past rely on the traditional The battery provides the required power; however, in recent years, environmental awareness has risen and the traditional battery is bulky, environmentally polluted, and the inconvenience of requiring regular battery replacement. Therefore, a clean, reliable and pollution-free micro-generator is a subject worth studying, while low-temperature heat How to use it effectively has also become a major challenge.

In addition, the conventional heat-pipe is widely used in the heat dissipation of electronic products because of its relatively good thermal conductivity, and its structure forms a low pressure state in the internal structure, which can reduce the saturation of the working liquid. Temperature, and can exclude the irrelevant non-condensable gas to increase the heat transfer efficiency, and the capillary is arranged on the inner wall. The capillary structure contains the working fluid in a phase change state, and the working liquid at the inner end evaporates into a gaseous state when the heat pipe is heated. When the heat is brought to the other end, when the working liquid in the gaseous state releases heat, it will condense into a liquid state and will flow back to the original place, causing the working liquid to evaporate and condense rapidly to form a circulation effect, so that the heat pipe achieves a fairly good heat dissipation effect; Therefore, a heat pipe type power conversion device for converting thermal energy into electrical energy is born, as shown in the third figure, a heat pipe type generator is provided with a turbine blade (7) in the heat pipe (6), the turbine A first driving rod (71) is disposed at a rear end of the blade (7), and a generator (8) is disposed in the heat pipe (6), and the generator (8) is provided with a sleeve through the heat (6) the pipe wall is connected to the turbine blade (7), and is connected to the first driving rod (71) of the turbine blade (7) by a second driving rod (81) in the sleeve; When the working fluid in the heat pipe (6) is vaporized by the heat of the heating pipe (61) to form steam, the steam gas flow can push the turbine blade (7) to generate power to rotate the first driving rod (71), and thereby drive the second driving rod. (81) rotation, the generator (8) can generate electricity; wherein the steam passes through the turbine After the blade (7), it is condensed into a liquid by the condensing pipe (62), flows into one end of the heating pipe (61), and is evaporated again, so as to achieve the purpose of heat dissipation and power generation.

However, the above-mentioned heat pipe generator drives the generator (8) to generate electricity by the rotation of the turbine blade (7), and it is difficult to minimize the turbine blade (7) to meet the space size of the electronic product, resulting in difficulty. The overall manufacturing cost is increased; in addition, the miniaturized turbine blade (7) has a low power generation efficiency, and is a heat pipe that utilizes the rotation of the turbine blade (7) to drive the generator (8) to generate electric power. The type of generator has the problem of miniaturization and poor power generation efficiency. Therefore, how to develop an innovative design that can be more ideal and practical is subject to the goals and directions of the relevant industry.

Nowadays, the inventor is in view of the fact that the above-mentioned existing heat pipe generators still have many defects in actual implementation, so it is a tireless spirit and is supplemented by its rich professional knowledge and years of practical experience. Improvements have been made and the present invention has been developed based on this.

The main object of the present invention is to provide a piezoelectric micro-generator that uses a steam flow generated in a hollow tube as a power source to drive a piezoelectric element to generate vibration and then generate electricity, and has a considerable flexibility in overall size, in today's technology electronic products. Under the light and thin, it can not only solve the problem that the heat dissipation of electronic products is not easy, but also convert the thermal energy into useful electric energy, and further improve the energy utilization efficiency of the piezoelectric micro-electric power generation device.

In order to achieve the above-described implementation, the inventors propose a piezoelectric micro-electric power generation device, which mainly includes a hollow tube body, an inner tube and a piezoelectric element; wherein the hollow tube body can be, for example, copper or aluminum, and a metal material such as stainless steel, which has a closed space, and the sealed space defines a vaporization end containing a working liquid and a condensation end corresponding to the evaporation end by a partition; the inner tube is disposed through the partition plate. And a necking portion (for example, a nozzle structure) is disposed on a side of the inner tube away from the evaporation end, so that the airflow passing through the opening of the necking portion has a faster speed, wherein the hollow tube system will have a phase change operation. The liquid is vaporized at the evaporation end and then opened to the condensation end through the neck portion, and is cooled and condensed at the condensation end and then flows back to the evaporation end to form a cycle, and the piezoelectric element is disposed in the closed space corresponding to the opening of the neck portion, The airflow ejected from the opening of the neck portion drives the vibration of the piezoelectric element to generate electric power; wherein the working liquid may be water, methanol, acetone, ammonia, and related refrigerant.

Thereby, the circulating gas flow generated by the gas-liquid phase transition mechanism of the working liquid in the hollow pipe body can drive the piezoelectric element to vibrate and then achieve the power generation effect, and the use of the piezoelectric material has considerable flexibility in size, so that The volume of the power generating device can be greatly reduced, so that the piezoelectric micro-electric power generating device of the present invention can more easily achieve power generation in a smaller size than the conventional heat pipe generator that uses the turbine blade to rotate the generator to generate electricity, and can not only solve the present problem. The problem of heat dissipation of miniaturized electronic products can further improve the energy utilization efficiency. Moreover, since the steam can pass through the neck of the inner tube, the airflow speed can be increased, resulting in more severe vibration of the piezoelectric element and relatively higher lifting. The efficiency of conversion of thermal energy into electrical energy.

In an embodiment of the present invention, the hollow tubular body may be provided with a capillary structure for the working liquid to be accommodated on the inner wall thereof, and a hole is formed in the corresponding capillary structure of the partition plate, so that the gas phase of the working liquid is condensed. After the end cooling condenses into a liquid phase, it can flow back to the evaporation end via the capillary structure to form a circulation effect, and the capillary structure can also provide a heat transfer area to increase the heat transfer efficiency.

In an embodiment of the invention, the wall of the hollow tubular body is formed by a discontinuous first casing and a second casing, and the first and second casings are joined by an airtight joint to make the hollow The inside of the pipe body is in an airtight state, which can prevent the outside air from entering or the vapor of the working liquid vaporized at the evaporation end from leaking out.

In an embodiment of the present invention, the closed space at the condensation end may be provided with a cantilever, one end of the cantilever is connected to the inner wall of the hollow tube body, and the other end is used for connecting the piezoelectric element; wherein the cantilever is Further, the piezoelectric element is further clamped by a conductive clamp to facilitate adjusting the distance between the piezoelectric element and the opening of the neck portion, and the conductive clamp is electrically connected to a conductive line passing through the hollow tube body to generate the piezoelectric element. The power is drawn out, and the power drawn through the conductive line can be stored in a battery.

In an embodiment of the invention, the vertical distance between the piezoelectric element and the opening of the neck portion is less than 5 mm, and the axial direction of the opening of the piezoelectric element and the neck portion is perpendicular to each other to allow the steam flow from the neck portion to be ejected. The best torque can be generated for the piezoelectric element.

Further, the piezoelectric element of the present invention generates electricity by means of a steam to generate a vibration displacement, wherein the amplitude of the vibration displacement is related to the natural frequency of the piezoelectric element, That is, when the natural frequency of the piezoelectric element conforms to the frequency at which the vapor pushes the piezoelectric element, the amplitude will reach a maximum, and the amount of power generated at this time also reaches a maximum value; wherein the natural frequency of the piezoelectric element can be set by geometrical adjustment.

<this invention>

(1)‧‧‧ hollow body

(11)‧‧‧Confined space

(111)‧‧‧Evaporation end

(112) ‧ ‧ condensed end

(13) ‧ ‧ partition

(131)‧‧‧ holes

(14) ‧‧‧Capillary structure

(15) ‧ ‧ inner management

(151) ‧‧‧neck

(16)‧‧‧First housing

(17)‧‧‧Second housing

(18)‧‧‧Airtight joints

(2) ‧‧‧Working liquid

(3) ‧‧‧Piezoelectric components

(4) ‧‧‧cantilever

(41)‧‧‧Conductive fixture

(5) ‧‧‧ conductive lines

<existing>

(6) ‧ ‧ heat pipe

(61) ‧ ‧ heating tube

(62) ‧ ‧ condensing tube

(7) ‧‧‧ turbine blades

(71)‧‧‧First drive rod

(8)‧‧‧Generator

(81)‧‧‧Second drive rod

First: a schematic cross-sectional view of a piezoelectric micro-electric power generation device according to a preferred embodiment of the present invention

Second: a perspective view of the appearance of a piezoelectric element and a cantilever connected to a preferred embodiment of the present invention

Figure 3: Schematic diagram of the structure of a conventional piezoelectric micro-power generation device

The object of the present invention and its structural and functional advantages will be explained in conjunction with the specific embodiments according to the structure shown in the following drawings, so that the reviewing committee can have a more in-depth and specific understanding of the present invention.

First, referring to the first figure, a schematic cross-sectional view of a piezoelectric micro-electric power generation device according to a preferred embodiment of the present invention; it is noted that the present invention uses a vapor flow to drive the piezoelectric element (3) to generate vibration. Power generation, and the use of the piezoelectric element (3) is quite flexible in size, resulting in a large reduction in the overall size of the power generating device, making it suitable for use in electronic devices for energy efficiency, and The piezoelectric type micro power generation device of the preferred embodiment mainly includes: a hollow tubular body (1) having a closed space (11), the closed space (11) defining a vaporizing end (111) containing the working liquid (2) and a vaporizing end by a partition plate (13) (111) corresponding to the condensation end (112), and the evaporation end (111) to the condensation end (112) can generate a gas flow; wherein the hollow tube body can be made of metal such as copper, aluminum, and stainless steel, and work The liquid can be water, methanol, acetone, ammonia and related refrigerants; An inner tube (15) is disposed through the partition plate (13), and a neck portion (151) is disposed on a side of the inner tube (15) away from the evaporation end (111) to open the opening through the neck portion (151) The air flow has a faster speed; wherein the neck portion (151) can be, for example, a nozzle structure; wherein the hollow tube body (1) is a working liquid (2) having a phase change at the evaporation end (111) The vaporization is further opened to the condensation end (112) through the neck portion (151), and is cooled and condensed at the condensation end (112) and then flows back to the evaporation end (111) to form a cycle at which the evaporation end (111) is vaporized. The airflow is as indicated by the dashed arrow in the first figure, and the state in which the airflow is cooled and condensed to the working fluid (2) at the condensation end (112) is indicated by the solid arrow in the figure; A piezoelectric element (3) is located at the opening of the constricted portion (151) in the sealed space (11), and the airflow ejected from the opening of the neck portion (151) drives the vibration of the piezoelectric element (3) to generate electric power.

Furthermore, the above hollow tube body (1) may be provided with a capillary structure (14) (capillary stru) for the working liquid (2) to be accommodated on the inner wall thereof. Cture), and the partition (13) is provided with a hole (131) corresponding to the capillary structure (14); when the gas phase of the working liquid (2) is cooled and condensed into a liquid phase at the condensation end (112), the capillary structure can be passed through (14) moving downward and flowing back to the evaporation end (111) to form a cycle effect, and the capillary structure can also provide a heat transfer area to increase heat transfer efficiency.

In addition, in the embodiment, the wall of the hollow pipe body (1) is constituted by the discontinuous first casing (16) and the second casing (17), and the first and second casings (16), (17) The airtight joint (18) is further engaged, so that the inside of the hollow tubular body (1) is in an airtight state, and the outside air or the vapor of the working liquid (2) vaporized at the evaporation end (111) is prevented from leaking out.

Furthermore, please refer to the second figure, which is a perspective view showing the appearance of the piezoelectric element and the cantilever of the preferred embodiment of the present invention. In this embodiment, the sealed space at the condensation end (112) (11) a cantilever (4) can be provided, one end of the cantilever (4) is connected to the inner wall of the hollow tube body (1), and the other end is used for connecting the piezoelectric element (3); wherein the cantilever (4) can be Further, the piezoelectric element (3) is sandwiched by a conductive clamp (41) to conveniently adjust the distance between the piezoelectric element (3) and the opening of the necking portion (151), and the conductive fixture (41) is electrically connected to the through hole. The conductive line (5) of the empty tube body (1) is used to extract the electric power generated by the piezoelectric element (3), and the electric power drawn from the conductive line (5) can be stored in a battery (not shown).

The piezoelectric type micro power generation device according to the above preferred embodiment is actually implemented When referring to the first figure, the vertical distance between the piezoelectric element and the opening of the neck portion is less than 5 mm, and the axial direction of the opening of the piezoelectric element and the neck portion is perpendicular to each other so as to be ejected by the neck portion. The steam flow can produce an optimal torque to the piezoelectric element; when the hollow tube body (1) is heated, the working liquid (2) accommodated at the evaporation end (111) will undergo a phase change, and the liquid phase will be converted into a gas phase. Steam, so that the steam flow can flow from the evaporation end (111) to the condensation end (112); it is worth noting that the waste heat is recycled to achieve the heat dissipation effect of the hollow tube body (1). The basic principle and structure are generally used by those skilled in the art. It is known that it will not be described in detail here; and because the steam flow (shown by the dotted arrow in the figure) has a neck portion (151) which can be a nozzle structure, the steam passes through the neck portion (151). The gas flow velocity of the steam can be increased, and the piezoelectric element (3) is driven by the extremely rapid airflow to generate violent vibration and then generate electricity, and the efficiency of power generation increases as the velocity of the airflow increases; in this embodiment, the piezoelectric The component (3) is made of polyvinylidene fluoride (PVDF) piezoelectric material. It is made up of an area of 40 mm × 13 mm and a thickness of 0.28 μm, and the upper and lower layers of the piezoelectric element (3) are coated with conductive silver. When the piezoelectric element (3) vibrates, due to the special intergranular atom between the materials Arrangement causes an electric dipole moment inside the piezoelectric material. At this time, in order to resist the change of the stress, the piezoelectric material generates a positive and negative electric charge on the surface of the material to maintain the internal molecular structure of the material. Voltage generating is thus generated, and the generated power can be stored in an external battery by the conductive line (5).

When the steam flow passes through the piezoelectric element (3), it reaches the hollow tube (1) Condensing end (112), and releasing heat at the condensation end (112) to condense into a liquid working liquid (2) on the inner wall of the hollow tube body (1), and then through the inner wall of the hollow tube body (1) The capillary structure (14) sends the liquid working liquid (2) back to the evaporation end (111) and is evaporated again to form a circulation path as indicated by a solid arrow and a dotted arrow, and the piezoelectric element is driven by the airflow thus repeated (3) The vibration is generated to achieve the purpose of heat dissipation and power generation at the same time; in addition, the hollow tube body (1) of the present invention does not have to be a straight tube design; in addition, the gravity-based factor is such that the condensed liquid is easily recirculated, and the operation is hollow. The tube body (1) can be placed in a vertical ground manner, and the evaporation end (111) is preferably disposed at a lower end with respect to the condensation end (112) to increase the cycle efficiency, but the hollow use is not limited in practical use. The orientation of the pipe body (1).

It should be noted that the number of inner tubes (15) and corresponding piezoelectric elements (3) of the present invention can be designed according to actual needs, so that no matter several inner tubes (15) and corresponding piezoelectric elements (3) The scope of the invention is intended to be in the spirit and scope of the invention.

It can be seen from the above description that the present invention has the following advantages compared with the prior art:

1. The present invention drives the piezoelectric element to vibrate by the circulating airflow generated by the liquid-liquid phase transition mechanism of the working liquid in the hollow tube body, thereby achieving the power generation effect, and the piezoelectric material has considerable flexibility in size. The piezoelectric micro-electric power generation device of the present invention makes the heat pipe generator which is driven by the turbine blade to drive the generator to generate electricity more easily than the conventional one. The purpose of generating electricity in a smaller size not only solves the problem of heat dissipation of today's miniaturized electronic products, but also further enhances energy utilization efficiency.

2. The piezoelectric micro-electric power generation device of the present invention boosts the air flow velocity of the steam by the inner tube having the neck portion to drive the piezoelectric element to generate relatively severe vibration, thereby improving the efficiency of converting thermal energy into electric power.

3. The piezoelectric micro-generator device of the present invention can design the natural frequency of the piezoelectric element by using geometrical dimensions, and can amplify the displacement of the piezoelectric element when the system frequency is close to the natural frequency, thereby increasing the power generation amount for better power generation. effectiveness.

In summary, the piezoelectric micro-electric power generation device of the present invention can achieve the intended use efficiency by the above-disclosed embodiments, and the present invention has not been disclosed before the application, and has completely complied with the patent law. Regulations and requirements.爰Issuing an application for a patent for invention in accordance with the law, and asking for a review, and granting a patent, is truly sensible.

The illustrations and descriptions of the present invention are merely preferred embodiments of the present invention, and are not intended to limit the scope of the present invention; those skilled in the art, which are characterized by the scope of the present invention, Equivalent variations or modifications are considered to be within the scope of the design of the invention.

(1)‧‧‧ hollow body

(11)‧‧‧Confined space

(111)‧‧‧Evaporation end

(112) ‧ ‧ condensed end

(13) ‧ ‧ partition

(131)‧‧‧ holes

(14) ‧‧‧Capillary structure

(15) ‧ ‧ inner management

(151) ‧‧‧neck

(16)‧‧‧First housing

(17)‧‧‧Second housing

(18)‧‧‧Airtight joints

(2) ‧‧‧Working liquid

(3) ‧‧‧Piezoelectric components

(4) ‧‧‧cantilever

(41)‧‧‧Conductive fixture

(5) ‧‧‧ conductive lines

Claims (13)

A piezoelectric micro-electric power generation device is suitable for an electronic device. The piezoelectric micro-electric power generation device mainly comprises: a hollow tube body having a closed space, the sealed space defining a working liquid by a partition plate An evaporation end and a condensation end corresponding to the evaporation end, and the evaporation end generates a gas flow to the condensation end; an inner tube is disposed through the partition plate, and the inner tube is disposed away from the evaporation end side The neck portion has a relatively fast speed of the airflow passing through the opening of the neck portion; and a piezoelectric element located at the opening of the sealed space corresponding to the neck portion, and the air current drives the vibration of the piezoelectric element to generate electricity . The piezoelectric micro-electric power generation device according to claim 1, wherein the neck portion is a nozzle structure. The piezoelectric micro-electric power generation device according to claim 1, wherein a capillary structure for accommodating the working fluid is disposed on an inner wall of the hollow tubular body, and a capillary structure corresponding to the separator is disposed. Hole. The piezoelectric micro-electric power generation device according to claim 1, wherein the hollow tube system vaporizes the working liquid at the evaporation end through the neck opening to the condensation end, and cools the condensation at the condensation end. It flows back to the evaporation end to form a cycle. The piezoelectric micro-electric power generation device according to claim 1, wherein a vertical distance between the piezoelectric element and the opening of the neck portion is less than 5 mm. The piezoelectric micro-electric power generation device according to claim 1, wherein the piezoelectric element and the axial direction of the neck opening are perpendicular to each other. The piezoelectric micro-electric power generation device according to claim 1, wherein a closed space is provided in the sealed space at the condensation end, the one end of the cantilever is connected to the hollow tube body, and the other end is connected to the piezoelectric element. . The piezoelectric micro-electric power generation device according to claim 7, wherein the cantilever further sandwiches the piezoelectric element with a conductive jig, so that the distance between the piezoelectric element and the opening of the neck portion can be adjusted. The piezoelectric micro-electric power generation device according to claim 8, wherein the conductive jig is electrically connected to a conductive line passing through the hollow tube body to extract electric power generated by the piezoelectric element. The piezoelectric micro-electric power generation device according to claim 9, wherein the electric power drawn by the conductive line is stored in a battery through the energy storage circuit. The piezoelectric micro-electric power generation device according to claim 1, wherein the wall of the hollow tubular body is formed by a discontinuous first casing and a second casing, the first and second casings. The inner portion of the hollow tubular body is in an airtight state by being joined by a gastight joint. The piezoelectric micro-electric power generation device according to claim 1, wherein the material of the hollow tubular body is a group of copper, aluminum, and stainless steel metal materials. The piezoelectric micro-electric power generation device according to claim 1, wherein the working fluid system is a group consisting of water, methanol, acetone, and ammonia.