CN111726026A - A composite energy harvester and wearable electronic device - Google Patents

Abstract

The invention discloses a composite energy collector and a wearable electronic device. The composite energy harvester includes an upper body and a lower body, and the upper body and the lower body are oppositely arranged and spaced to form a cavity; the upper body sequentially includes: magnets, upper electrodes, and friction films from top to bottom; the lower body is from top to bottom. It sequentially includes: a middle electrode, a piezoelectric film, an insulating layer with an induction coil, and a lower electrode; the upper body and the lower body contact and rub against each other when pressed by an external force. The invention proposes a power generation system with three coupling modes of piezoelectricity, friction and electromagnetic, realizes the complementary advantages of the three power generation modes, and can output high voltage and current signals, which not only solves the problem that the traditional single power generation mode has low output power and is not easy to be affected by the human body The problems of wearable electronic devices; and the present invention has simple structure, easy manufacture, low cost, easy miniaturization, more stability, and is more convenient for the use of wearable electronic devices of the human body, and also solves the complex structure and manufacturing of the existing composite generators. High cost and poor practical stability.

Description

A composite energy harvester and wearable electronic device

technical field

The invention relates to the technical field of energy conversion devices, and relates to a friction-piezoelectric-electromagnetic composite energy harvester that can adapt to external extrusion.

Background technique

With the increasing trend of energy cleaning and high efficiency, the related research work of new energy harvesting devices has made great progress in recent years. At the macro level, the normal operation of society and people's daily life depend on the electrical energy generated and delivered by conventional or new energy sources; at the micro level, personal electronic products, implantable biosensors, micro-electromechanical systems, environmental Monitoring sensors even as small as nanorobots, micromotors, etc. require independent, persistent power supplies to power them.

Mechanical energy is currently converted into electrical energy, including electromagnetic induction, electrostatic induction, piezoelectric effect, and triboelectricity. However, the above-mentioned power generation devices based on single characteristics are subject to different constraints and limitations, such as: generators based on piezoelectric characteristics have high output power and strong charging capacity, but the output voltage is not high; generators based on friction characteristics have high output voltage, But the output current is small, and the output pulse width is narrow, the charging capacity is weak, and so on.

The composite harvesting device, which combines the single-characteristic power generation structure ingeniously, has high efficiency and wide application range, and is suitable to replace the traditional single energy harvesting device.

In this regard, such as Chinese invention patent CN201610243461.0, friction-piezoelectric-magnetic-electric composite vibration micro-energy harvester, which suspends a magnet as a sensitive unit of the micro-energy harvester, improves the sensitivity of sensitive components, thereby The collection of mechanical energy is realized; at the same time, the efficient collection of mechanical energy is realized by integrating the piezoelectric, magnetoelectric, and frictional power generation units with complementary working modes. From the middle to the two sides, the collector includes an electromagnet, a friction film, an electromagnetic induction coil, a piezoelectric layer and a structural base in sequence. The electromagnetic layer adopts a magnetic levitation design, which avoids the mechanical connection on the sensitive elements in the traditional structure, and can sense smaller The piezoelectric layer adopts a structural design in which one end is fixed and connected to the electrode, and the other end is supported by dislocation, and the principle of magnetic field homopolar repulsion is used to sense the displacement change of the sensitive element (suspended magnet), causing the piezoelectric film to deform. . The friction layer adopts the method of stacking double-layer films, and uses the suspension magnet to vibrate and contact the friction layer to induce electric charges between the two layers of friction films. However, there are still problems such as complex structure, difficult to manufacture and difficult to miniaturize.

Another example is Chinese invention patent CN201710270093.3, an electromagnetic friction piezoelectric composite energy harvester. Specifically, permanent magnets are placed on both sides of the inside of the collector shell, the rotating shaft is connected to the shell through bearings, and the concave cantilever is designed. The beam is fixed on the rotating shaft, the two ends of the cantilever beam are fixedly connected to the hemispherical mass blocks, the piezoelectric ceramics covered with the buffer layer are installed inside the shell, the cantilever beam is wound with a coil, and a second friction layer is attached to the outside of the coil. The corresponding positions between the second friction layer and the casing are the first friction layer, the flexible piezoelectric material and the insulating filling layer. The collected energy is output through the external circuit of the first electrode layer and the second electrode layer, and the first electrode layer is connected to the flexible The piezoelectric material and the first friction layer and the second electrode layer are located on the upper part of the rotating shaft, and the coil and the second friction layer are connected by wires. The advantage is that the vibration energy is converted into electrical energy, the output energy is superimposed and amplified, and the energy conversion efficiency of the device is further improved. However, there are still problems such as complex structure, difficult manufacture, high cost, and difficulty in practical application.

SUMMARY OF THE INVENTION

Based on this, it is necessary to provide a composite energy harvester in view of the above technical problems. The present invention proposes a power generation system with three coupling modes of piezoelectric, friction and electromagnetic, so as to realize the complementary advantages of the three power generation modes, and can output high power The voltage and current signals not only solve the problems that the traditional single power generation form has low output power and are not easy to be used by human body wearable electronic devices; but also the present invention has simple structure, easy manufacture, low cost, easy miniaturization, more stability, and more convenience to the human body. The use of wearable electronic devices also solves the problems of complex structure, high manufacturing cost, and poor practical stability of the existing composite generators; the invention makes full use of external pressure to convert mechanical energy into electrical energy, and external force leads to piezoelectric, frictional and electromagnetic three. These methods can simultaneously generate electricity and solve the problem of long-term power supply for wearable electronic devices. When the outside world acts on the movement of the device, it can effectively convert mechanical energy into electrical energy, and the converted energy can be used for continuous power supply of wearable devices.

The present invention also provides a wearable electronic device having the above-mentioned composite energy harvester.

In order to solve the above-mentioned technical problems, the present invention provides a composite energy harvester, which adopts the following technical solutions:

A composite energy harvester, comprising an upper body and a lower body, the upper body and the lower body are oppositely arranged and spaced apart to form a cavity;

The upper body sequentially includes: a magnet, an upper electrode, and a friction film from top to bottom;

The lower body sequentially includes from top to bottom: a middle electrode, a piezoelectric film, an insulating layer with an induction coil, and a lower electrode;

When the energy harvester is squeezed by an external force, the upper body and the lower body contact and rub against each other to generate triboelectric power. At the same time, the pressure of the piezoelectric film changes to cause piezoelectric power generation, and the voltage at both ends of the induction coil changes. To achieve electromagnetic power generation.

As an improvement of the composite energy harvester provided by the present invention, the friction film is an electret film.

As an improvement of the composite energy harvester provided by the present invention, the thickness of the electret film ranges from 10 μm to 10 mm.

As an improvement of the composite energy harvester provided by the present invention, the thickness of the insulating layer ranges from 0.2 mm to 5 mm.

As an improvement of the composite energy harvester provided by the present invention, the height of the cavity ranges from 10 μm to 100 mm.

As an improvement of the composite energy harvester provided by the present invention, the upper body further includes an upper rigid carrier for bearing, and the lower body further includes a lower rigid carrier for bearing.

As an improvement of the composite energy harvester provided by the present invention, the upper body and the lower body are connected and supported by elastic connectors.

As an improvement of the composite energy harvester provided by the present invention, the thickness of the upper electrode, the middle electrode and the lower electrode ranges from 1 nm to 2 μm.

A wearable electronic device has the composite energy harvester as described above.

Compared with the prior art, the present invention has the following beneficial effects:

The invention proposes a composite energy harvester with three coupling modes of piezoelectric, friction and electromagnetic, which realizes the complementary advantages of the three power generation modes. The external force causes the three modes of piezoelectric, friction and electromagnetic to act at the same time to generate electricity, which can output high power. The voltage and current signals not only solve the problems that the traditional single power generation form has low output power and are not easy to be used by human body wearable electronic devices; but also the present invention has simple structure, easy manufacture, low cost, easy miniaturization, more stability, and more convenience to the human body. The use of wearable electronic devices also solves the problems of complex structure, high manufacturing cost, and poor practical stability of the existing composite generators; the invention makes full use of external pressure to convert mechanical energy into electrical energy, and solves the long-term power supply problem of wearable electronic devices for human bodies. When the outside world acts on the movement of the device, the effective conversion of mechanical energy into electrical energy can be realized, and the converted energy can be used for continuous power supply of the wearable device of the human body.

Description of drawings

In order to illustrate the solutions in the present application or the prior art more clearly, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description belong to the present application. In some embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

1 is a perspective view of a composite energy harvester according to the present invention, and the composite energy harvester is not squeezed by external force;

Fig. 2 is the front view of Fig. 1;

3 is a perspective view of the composite energy harvester of the present invention when it is squeezed by an external force;

4 is a schematic diagram of the working principle of the composite energy harvester of the present invention;

Fig. 5 is a kind of curve of the current and voltage test of the piezoelectric part Vp of the composite energy harvester of the present invention;

Fig. 6 is a kind of curve of current and voltage test of the friction part V _T of the composite energy harvester of the present invention;

FIG. 7 is a curve of the current and voltage _test of the cutting magnetic field line part VM of the composite energy harvester of the present invention.

Detailed ways

In order to make those skilled in the art better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only Embodiments are part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " Rear, Left, Right, Vertical, Horizontal, Top, Bottom, Inner, Outer, Clockwise, Counterclockwise, Axial, The orientations or positional relationships indicated by "radial direction", "circumferential direction", etc. are based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the indicated devices or elements. It must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as a limitation of the present invention.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically defined.

In the present invention, unless otherwise expressly specified and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection , or integrated; it can be a mechanical connection or an electrical connection or can communicate with each other; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two components or the interaction relationship between the two components, unless otherwise expressly qualified. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

In order to make those skilled in the art better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings.

Referring to FIGS. 1 and 2 , this embodiment provides a composite energy harvester, which is coupled with three power generation modes, piezoelectric, friction and electromagnetic. Specifically, the composite energy harvester includes an upper body 100 and a lower body. The main body 200, the upper main body 100 and the lower main body 200 are disposed opposite to each other and form a cavity 300 at intervals to provide space requirements for the relative movement of the upper main body 100 and the lower main body 200; further, the upper main body 100 is from top to bottom It includes the magnet 110, the upper electrode 120, and the friction film 130 in sequence. The lower body 200 includes, from top to bottom, the middle electrode 210, the piezoelectric film 220, the insulating layer 230 with the induction coil 231, and the lower electrode 240. The friction film 130 corresponds to the middle electrode 210. When the energy harvester is squeezed by an external force, the upper body 100 and the lower body 200 are in contact and rubbing against each other to generate friction power. At the same time, the pressure of the piezoelectric film changes, causing the pressure To generate electricity, the voltage at both ends of the induction coil changes to realize electromagnetic power generation.

In specific implementation, when the energy harvester is squeezed by an external force, the friction film 130 and the middle electrode 210 are in contact and move relative to each other, and frictional electrification occurs, and the electric energy is output through the upper electrode 120 and the middle electrode 210 . Wherein, the friction film 130 is preferably but not limited to an electret film, and the electret film can be a PTFE electret film, which has charge adsorption and separation effects, thereby causing the frictional contact and separation of materials to be electrified, At the same time, polyperfluoroethylene propylene (FEP), polypropylene (PP), polyvinylidene fluoride (PVDF), and L-polylactic acid (PLLA) can also be used as electret films. The thickness of the film is preferably but not limited to 10 μm. -10mm.

In specific implementation, when the energy harvester is squeezed by an external force, the piezoelectric film 220 in the lower body 200 is deformed, causing piezoelectric power generation, and electrical energy is output through the middle electrode 210 and the lower electrode 240 . Wherein, the piezoelectric film 220 is preferably, but not limited to, a PVDF piezoelectric film 220, and may also be a piezoelectric composite material (eg, PDMS-BaTiO3, PVDF-BaTiO3, or PDMS-ZnO, etc.).

When specifically implemented, the purpose of the cavity 300 is to provide a suspended structure. When the energy harvester is squeezed by an external force, the cavity 300 will be deformed accordingly. According to the effect of cutting magnetic field lines, the magnet 110 interacts with the induction coil 231, and the voltage at both ends of the induction coil 231 changes. Both ends of the induction coil 231 are output. Wherein, the height range of the cavity 300 is preferably but not limited to 10 μm-100 mm. The thickness range of the insulating layer 230 embedded with the induction coil 231 is preferably but not limited to 0.2mm-5mm. The closer the magnet 110 is to the induction coil 231, the stronger the magnetic field in the surrounding space. The sense line is too weak, and the power generation is greatly reduced.

The insulating layer 230 can be made of tough and highly elastic materials, such as rubber tape, silica gel, PDMS, etc. Such materials are easy to obtain and cheap, and it is easy to embed the induction coil 231 into it. 231 is separated from the piezoelectric film 220 and the lower electrode 240 by the insulating layer 230 to reduce the energy loss of coupling.

Furthermore, since the insulating layer is an elastic material and also has a buffering function, the upper body 100 and the lower body 200 can be prevented from excessively contacting when the energy harvester is squeezed by an external force. It should be noted that under normal circumstances, excessive friction and damage will not occur.

The purpose of the magnet 110 is to provide a space electromagnetic field for the induction coil 231, so as to cut the magnetic induction line to generate electricity. The magnet 110 is a magnetic material capable of generating a strong magnetic field, such as natural lodestone, ferrite magnetic material, neodymium iron boron magnetic material, samarium cobalt magnetic material, alnico magnetic material, rare earth alloy or iron silicon alloy, and the like.

The shape of the induction coil 231 can be arc, round, square, the number of layers of the coil can be one layer or multiple layers, the coil material is generally copper wire, and can also be gold, silver, aluminum and alloys. class wire.

In this embodiment, the thickness range of the upper electrode 120 , the middle electrode 210 and the lower electrode 240 is preferably but not limited to 1 nm-2 μm, and the materials are all metals or semiconductor materials with good conductivity and easy to lose electrons. Gold, silver, platinum, copper, aluminum, titanium or tungsten, etc.; semiconductor materials include indium tin oxide (ITO), III-V compounds or highly doped silicon, etc. The electrodes can be formed by electron beam evaporation or magnetic Controlled sputtering, etc. The thicknesses of the upper electrode 120 , the middle electrode 210 and the lower electrode 240 may be the same or different, and may be set according to actual conditions.

Further, the upper body 100 further includes an upper rigid carrier 140 for bearing, and the lower body 200 further includes a lower rigid carrier 250 for bearing. Specifically, the other side of the magnet 110 is fixed on one side of the upper rigid carrier 140 , and the lower electrode 240 is formed on one side of the lower rigid carrier 250 . The materials of the upper rigid carrier and the lower rigid carrier may be hard materials such as acrylic plates.

Further, when the composite energy harvester is not pressed by an external force, the upper body 100 and the lower body 200 are connected and supported by the elastic connecting member 400, so that the upper body 100 and the lower body 200 are spaced apart from each other. the cavity 300. The material of the elastic connector 400 may be elastic materials such as PI, PET, and the like. The elastic connecting member 400 may be a sheet-like structure, a corrugated structure, a column-like structure and the like. As an embodiment, both ends of the elastic connecting member 400 are respectively connected to the upper rigid carrier 140 and the lower rigid carrier 250 . The state of the composite energy harvester when it is not squeezed by external force is shown in FIG. 1 , and the state when it is squeezed by external force is shown in FIG. 3 .

As shown in Figure 4, the working principle of the composite energy harvester of the present invention is as follows:

When the collector is subjected to external pressure, the elastic connecting member 400 undergoes mechanical deformation, which drives the upper body 100 and the lower body 200 to move relative to each other, and the friction film 130 and the middle electrode 210 contact and rub each other to achieve triboelectric power generation V _T (current and voltage curves are shown in FIG. 6 ), in addition, the pressure of the piezoelectric film 220 changes to cause piezoelectric power generation _VP (current and voltage curves are shown in FIG. 5 ), and the cavity 300 will generate corresponding Mechanical deformation, according to the cutting magnetic field line effect, due to the interaction between the magnet 110 and the induction coil 231, the voltage at both ends of the induction coil 231 changes to achieve electromagnetic power generation _VM (current and voltage curves are shown in Figure 7), and then realize piezoelectricity. , friction and electromagnetic composite energy harvesting device to generate electricity.

Through the above design, the present invention provides a piezoelectric, friction and electromagnetic composite energy harvesting device, that is, a composite energy harvester. When the external pressure exerts a force on the device, the mechanical energy of the force is converted into electrical energy. Due to the joint action of the three mechanisms, that is, the external force causes the piezoelectric, friction and electromagnetic methods to simultaneously generate electricity, so that high-efficiency energy can be achieved. collect.

The invention can output high voltage and current signals through the complementary advantages of the three power generation modes, which not only solves the problem that the traditional single power generation mode has low output power and is not easy to be used by human wearable electronic devices; The structure of the device is simple, the overall structure of the device is reliable and easy to implement, the processing technology is simple, the cost is low, the yield is high, it can be mass-produced, it is easy to industrialize, it is easy to miniaturize, it is more stable, and it is more convenient for the use of wearable electronic devices. The composite generator has the problems of complex structure, high manufacturing cost and poor practical stability.

The invention makes full use of external pressure to convert mechanical energy into electrical energy, and solves the problem of long-term power supply for human wearable electronic devices. Uninterrupted power supply.

It should be noted that the external force on the collector may be generated during use, or may be exerted by the user for generating electricity.

The present invention also provides a wearable electronic device, which has the above-mentioned composite energy harvester as a power supply device for the wearable electronic device. For example, when the wearable electronic device is a smart watch, the composite energy harvester is embedded on the watch strap of the smart watch, so that the composite energy harvester converts the mechanical energy generated by the movement of the wrist into electrical energy, And supply power to the smart watch to realize the self-driving of the smart watch.

Obviously, the above-described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The accompanying drawings show the preferred embodiments of the present application, but do not limit the scope of the patent of the present application. This application may be embodied in many different forms, rather these embodiments are provided so that a thorough and complete understanding of the disclosure of this application is provided. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or perform equivalent replacements for some of the technical features. . Any equivalent structures made by using the contents of the description and drawings of this application, which are directly or indirectly used in other related technical fields, are all within the scope of protection of the patent of this application.

Claims (10)

1. A composite energy collector is characterized by comprising an upper main body and a lower main body, wherein the upper main body and the lower main body are oppositely arranged and form a cavity at intervals;

go up the main part from top to bottom and include in proper order: a magnet, an upper electrode, and a friction film;

the lower main part from top to bottom includes in proper order: the piezoelectric sensor comprises a middle electrode, a piezoelectric film, an insulating layer with an induction coil and a lower electrode;

when the energy collector is extruded by an external force, the upper main body and the lower main body are in mutual contact friction to perform friction power generation, meanwhile, the pressure of the piezoelectric film changes to cause piezoelectric power generation, and the voltages at the two ends of the induction coil change to realize electromagnetic power generation.

2. The composite energy harvester of claim 1, wherein the tribofilm is an electret film.

3. The composite energy harvester of claim 2, wherein the electret film has a thickness in the range of 10 μ ι η to 10 mm.

4. The composite energy harvester of claim 1, wherein the insulating layer has a thickness in a range of 0.2mm to 5 mm.

5. The composite energy harvester of claim 1, wherein the cavity has a height in the range of 10 μ ι η to 100 mm.

6. The composite energy harvester of claim 1, wherein the upper body further comprises an upper rigid carrier for carrying, and the lower body further comprises a lower rigid carrier for carrying.

7. The composite energy harvester of claim 1, wherein the upper body and the lower body are connected and supported by a resilient connecting member.

8. The composite energy harvester of claim 7, wherein the resilient connecting member is PI or PET.

9. The composite energy harvester of claim 1, wherein the upper, middle and lower electrodes have a thickness in the range of 1nm to 2 μ ι η.

10. Wearable electronic device, characterized in that it has a composite energy harvester according to any of claims 1 to 9.

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