CN106849599A - A kind of electromagnet-friction Piezoelectric anisotropy formula energy collecting device - Google Patents

Abstract

The invention relates to an electromagnetic friction piezoelectric composite energy collector, which belongs to the technical field of micro-electromechanical systems and micro-energy sources. Permanent magnets are placed on both sides of the shell of the collector. The rotating shaft is connected to the shell through bearings. The cantilever beam with concave design is fixedly connected to the rotating shaft. The electroceramic is installed inside the shell, and a coil is wound on the cantilever beam. The second friction layer is attached to the outside of the coil. The corresponding position between the second friction layer and the shell is the first friction layer, flexible piezoelectric material and insulating filling. layer, the collected energy is output through the first electrode layer and the second electrode layer externally connected to the circuit, the first electrode layer is connected to the flexible piezoelectric material and the first friction layer, the second electrode layer is located on the upper part of the rotating shaft, and the coil and the second friction layer are connected by wires Floor. The advantage is that the vibration energy is converted into electric energy, and the output energy is superimposed and amplified to further improve the energy conversion efficiency of the device.

Description

An electromagnetic triboelectric composite energy harvester

technical field

The invention relates to the technical fields of micro-electromechanical systems (MEMS) and micro-energy sources, in particular to an electromagnetic-friction-piezoelectric composite energy collector.

Background technique

With the increasing trend of energy cleanliness and high efficiency, the research work on new energy harvesting devices has made great progress in recent years. Vibration energy harvester is a research focus of new energy harvesting devices, and its working methods mainly include electromagnetic, electrostatic and piezoelectric. In terms of electromagnetic type, Kulah et al., a research group of Middle East Technical University in Turkey, proposed a method of cantilever beam array with different natural frequencies to increase the resonance bandwidth, so that the energy of vibration signals with a wider frequency band can be collected; in terms of electrostatic type, Academician Wang Zhonglin Realized the TENGs nano triboelectric generator based on the coupling principle of triboelectrification and electrostatic induction; in terms of piezoelectricity, the piezoelectric generator developed by MIT and other institutions in the United States has an efficiency level of several hundred to one thousand μw/cm ³ .

However, the compound harvesting device, which cleverly combines a single working mode, has high efficiency and wide application, and is suitable to replace the traditional single energy harvesting device. In this regard, the micro-composite vibration energy harvester made by researchers such as Bin Yang from the National University of Singapore has realized the piezoelectric and electromagnetic conversion mechanism to obtain energy at the same time, but there are still problems such as low energy harvesting efficiency and complex structure. Zhang Xiaosheng of Peking University and others proposed a nanogenerator based on piezoelectric triboelectromagnetics to collect renewable energy in nature. However, there are still problems such as low piezoelectric energy collection efficiency and large energy loss. In summary, the problems of low collection efficiency and complex structure seriously limit the practicality of the composite energy harvester. For this reason, how to improve the energy conversion efficiency of the energy harvester through multi-mechanism compounding and special structural design, and develop practical energy harvesters Harvester products are a hot topic in the field of energy harvesting in the near future. In addition, there is no report on an autonomous vibration energy harvester that uses electromagnetic, piezoelectric, and frictional mechanisms to collect the mechanical energy of human motion.

Contents of the invention

The invention proposes an electromagnetic friction piezoelectric composite energy harvester to solve the problem of low collection efficiency existing in traditional single-form and composite-form energy harvesters.

The technical solution adopted by the present invention is: the two sides of the shell of the collector are symmetrically arranged with "gate" shaped permanent magnets with reversed magnetic poles, the rotating shaft is connected with the shell through bearings, and the cantilever beam with concave design is fixedly connected to the rotating shaft. The two ends of the cantilever beam are respectively fixedly connected to the hemispherical mass block, and the piezoelectric ceramics covered with the buffer layer correspond to the mass block one by one, and are installed inside the housing. A coil is wound on the cantilever beam, and a second friction layer is attached to the coil. The corresponding positions between the second friction layer and the shell are the first friction layer, the flexible piezoelectric material and the insulating filling layer in sequence. The collected energy is output through the first electrode layer and the second electrode layer through the external circuit, and the first electrode layer is connected to A flexible piezoelectric material and the first friction layer, the second electrode layer is located on the upper part of the rotating shaft, and the coil and the second friction layer are connected by wires;

The middle part of the cantilever beam of the present invention is concave inward;

According to the present invention, the contact surface of the first friction layer has arc-shaped grooves, and the contact surface of the second friction layer has corresponding arc-shaped protrusions;

The contact surfaces of the first friction layer and the second friction layer in the present invention are all planes;

The first friction layer of the present invention has microscopic protrusions on the friction surface;

The friction surface under the second friction layer of the present invention has microscopic protrusions;

The first friction layer of the present invention adopts polydimethylsiloxane PDMS;

The second friction layer of the present invention adopts polyamide PA;

The flexible piezoelectric material of the present invention adopts polyvinylidene fluoride PVDF;

The flexible piezoelectric material of the present invention is connected with the first friction layer by insulating glue.

The advantages of the present invention are: novel structure, vibration energy collection by using electromagnetic, piezoelectric and frictional mechanisms combined, energy harvester as a whole adopts a simple and efficient symmetrical structure design, providing a new type of human body movement mechanical energy collection method ;The cantilever beam design is adopted, the cantilever beam adopts a symmetrical concave structure, and there are mass blocks on both sides, increasing the force couple, increasing the vibration frequency of the cantilever beam, effectively increasing the output of electric energy, and improving the efficiency of energy collection; the invented shaft passes through The bearing is connected to the housing to reduce the frictional energy loss, and compared with the cantilever beam structure constrained by the fixed end, the connection of the rotating shaft releases a degree of freedom to reduce the energy loss of internal stress; the present invention uses piezoelectric ceramics and flexible piezoelectric materials together The piezoelectric energy harvesting unit is formed, which combines the advantages of high energy harvesting efficiency of piezoelectric ceramics, easy deformation of flexible piezoelectric materials, and convenient design, and the buffer layer is covered on the piezoelectric ceramics, and the energy harvesting efficiency of the piezoelectric energy harvesting unit and The service life has been improved.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is an overall view of the appearance of the present invention;

Fig. 3 is a structural schematic diagram of the friction structure scheme 1 of the present invention;

Fig. 4 is an overall appearance diagram of the second friction structure scheme of the present invention;

Fig. 5 is a structural schematic diagram of the second friction structure scheme of the present invention;

Fig. 6 is a schematic diagram of the winding of the cantilever beam and the coil of the present invention.

detailed description

The two sides of the collector housing 1 are symmetrically equipped with "gate"-shaped permanent magnets 2 with opposite magnetic poles. The rotating shaft 3 is connected to the housing 1 through the bearing 4. The concave cantilever beam 5 is fixedly connected to the rotating shaft 3. The two ends of the cantilever beam 5 are respectively fixedly connected to the hemispherical mass block 6, and the piezoelectric ceramic 8 covered with the buffer layer 7 corresponds to the mass block 6 one by one, and is installed inside the housing 1. A coil 9 is wound on the cantilever beam 5, and the coil 9 9 is attached with a second friction layer 11, and the corresponding positions between the second friction layer 11 and the housing 1 are the first friction layer 10, the flexible piezoelectric material 12 and the insulating filling layer 13, and the collected energy passes through the first electrode Layer 14 and the second electrode layer 15 are externally connected to the line output, the first electrode layer 14 is connected to the flexible piezoelectric material 12 and the first friction layer 10, the second electrode layer 15 is located on the upper part of the rotating shaft 3, and the coil 9 and the second friction layer are connected by wires 11.

When human body movement provides vibration excitation, the cantilever beam 5 with the coil 9 reciprocatingly rotates around the rotating shaft 3, and cuts the magnetic field line, and generates electric energy output according to the principle of electromagnetic induction. When the cantilever beam 5 rotates to a critical position, the first friction layer 10 It is in contact with the second friction layer 11 and undergoes relative motion to generate triboelectric energy output; at the same time, the piezoelectric ceramics 8 located on the upper and lower sides of the housing 1 are hit by the mass block 6, and the flexible piezoelectric material covered under the insulating filling layer 13 12 produces extrusion deformation, and the two together generate piezoelectric electric energy output;

The middle part of the cantilever beam 5 is concave inward;

The first friction layer 10 has arc-shaped grooves, and the second friction layer 11 has corresponding arc-shaped protrusions;

The contact surface between the first friction layer 10 and the second friction layer 11 is a plane;

There are microscopic protrusions on the friction surface of the first friction layer 10;

The lower friction surface of the second friction layer 11 has microscopic protrusions;

Described permanent magnet 2 adopts the magnetic material that produces strong magnetic field, as ferrite magnetic material, rubidium iron boron magnetic material, shirt drill magnetic material, aluminum nickel drill magnetic material etc.;

The coil 9 is formed by orderly winding metal wires (such as silver, copper, aluminum and their alloys, etc.) whose surface is covered with an insulating layer;

The piezoelectric ceramic 8 adopts traditional PZT material, the flexible piezoelectric material 12 adopts polyvinylidene fluoride PVDF, the buffer layer 7 contains conductive silica gel, and the material selection of the flexible piezoelectric material 12 and the insulating filling layer 13 will not affect the piezoelectric energy. Excessive internal stress is generated during the process of unit deformation and production capacity;

The first friction layer 10 is made of polydimethylsiloxane PDMS, and the second friction layer 11 is made of polyamide PA;

The flexible piezoelectric material 12 is connected with the first friction layer 10 by insulating glue, so as to reduce the energy loss of multi-mechanism coupling.

As shown in Figure 2 and Figure 3, when the cantilever beam rotates to the critical position, the contact area between the first friction layer and the second friction layer can reach the maximum, the first friction layer 10 is designed with arc-shaped grooves, and the second friction layer 11 has a corresponding The arc-shaped protrusions, and the upper and lower friction surfaces are treated with microscopic protrusions. This treatment method increases the effective friction area of the material and improves the energy collection efficiency.

As shown in Fig. 4 and Fig. 5, in order to simplify the structure and reduce the difficulty and cost of production, the concave-convex friction structure design of the first friction layer and the second friction layer can be simplified into a flat type.

As shown in Figure 6, the coil 9 is symmetrically wound on the concave cantilever beam 5, and the hemispherical mass blocks 6 are placed at both ends of the cantilever beam.

Claims (10)

1. An electromagnetic friction piezoelectric composite energy harvester, characterized in that: the two sides of the collector shell are symmetrically equipped with "gate" shaped permanent magnets with opposite magnetic poles, the rotating shaft is connected with the shell through a bearing, and the inner concave The cantilever beam with the shape design is fixed on the rotating shaft, and the two ends of the cantilever beam are respectively fixedly connected with the hemispherical mass blocks. A coil, a second friction layer is attached to the outside of the coil, and the corresponding positions between the second friction layer and the housing are sequentially the first friction layer, flexible piezoelectric material and insulating filling layer, and the collected energy passes through the first electrode layer and the second electrode layer. The electrode layer is externally connected to the line output, the first electrode layer is connected to the flexible piezoelectric material and the first friction layer, the second electrode layer is located on the upper part of the rotating shaft, and is connected to the coil and the second friction layer through wires. 2 . The electromagnetic triboelectric piezoelectric composite energy harvester according to claim 1 , wherein the middle part of the cantilever beam is concave inward. 3 . 3. A kind of electromagnetic friction piezoelectric composite energy harvester according to claim 1, characterized in that: the contact surface of the first friction layer has arc-shaped grooves, and the contact surface of the second friction layer has corresponding Curved raised. 4 . The electromagnetic triboelectric piezoelectric composite energy harvester according to claim 1 , wherein the contact surfaces of the first friction layer and the second friction layer are both planes. 5. The electromagnetic triboelectric piezoelectric composite energy harvester according to claim 1, characterized in that: there are microscopic protrusions on the friction surface of the first friction layer. 6 . The electromagnetic triboelectric piezoelectric composite energy harvester according to claim 1 , wherein there are microscopic protrusions on the friction surface under the second friction layer. 7 . 7 . The electromagnetic triboelectric piezoelectric composite energy harvester according to claim 1 , wherein the first friction layer is made of polydimethylsiloxane (PDMS). 8. An electromagnetic triboelectric piezoelectric composite energy harvester according to claim 1, characterized in that: the second friction layer is made of polyamide PA. 9 . The electromagnetic triboelectric piezoelectric composite energy harvester according to claim 1 , wherein the flexible piezoelectric material is polyvinylidene fluoride (PVDF). 10 . The electromagnetic triboelectric piezoelectric composite energy harvester according to claim 1 , wherein the flexible piezoelectric material and the first friction layer are connected by insulating glue. 11 .