Bistable piezoelectric energy collecting device

Abstract

The utility model relates to a bistable piezoelectric energy collecting device, and belongs to the technical field of new energy. Comprising a base, a mass block, rigid beams, elastic beams and piezoelectric patches on the beams. The rigid beam and the elastic beam are connected through the mass block, the device can achieve nonlinear bistable oscillation when the mass block slides along the center supporting column of the base under external excitation, and in other words, the mass block can jump between two stable balance states. During bistable oscillation, the kinetic energy of the mass block enables the piezoelectric plate on the elastic beam to be bent and deformed so as to realize energy collection. According to the utility model, the structure design is simple, the stability is high, the utilization rate of the piezoelectric material is improved by the array arrangement of the piezoelectric patches, and the energy harvesting efficiency is increased; the problems that an existing energy harvesting device is low in energy conversion efficiency, low in piezoelectric material utilization rate and narrow in vibration harvesting frequency bandwidth range are solved, and the energy harvesting device can be widely applied to energy supply of low-power-consumption electronic devices.

Description

Technical Field

[0001] This utility model relates to the field of energy recovery technology, and more specifically, to a bistable piezoelectric energy harvesting device. Background Technology

[0002] Vibration Energy Harvesting Technology (VEHT) can convert mechanical vibration energy into electrical energy to power low-power devices. VEHT is a revolutionary technology, particularly for wireless sensors, with the potential to develop self-powered wireless systems. If such a system can autonomously replenish the energy of its sensor network, it will significantly reduce maintenance costs and could even be permanently placed in hard-to-maintain locations. Vibration is a common physical phenomenon widely present in life and the environment, such as in household appliances, vehicles, the natural environment, and buildings. Vibration also exists in living phenomena, such as heartbeats and limb movements.

[0003] Currently, commonly used vibration energy harvesting methods include friction, electromagnetic, and piezoelectric methods. Friction energy harvesting technology relies on the relative sliding motion between two layers of frictional materials to directly convert the generated mechanical energy into electrical energy. However, this conversion process requires overcoming friction, which not only accelerates material wear but also shortens the lifespan of the device.

[0004] Electromagnetic energy harvesting technology follows Faraday's law of electromagnetic induction, converting the system's mechanical energy into electrical energy through the relative motion between a coil and a magnet. However, this method typically requires large magnets and coils, resulting in a bulky overall device. In contrast, piezoelectric energy harvesting technology exhibits unique advantages. It utilizes the positive piezoelectric effect of piezoelectric materials, directly converting the mechanical energy generated during the deformation of these materials into electrical energy. Due to its relatively simple structure and high energy harvesting efficiency, piezoelectric energy harvesting technology demonstrates enormous development potential and broad application prospects.

[0005] To improve the efficiency of vibration energy harvesting, researchers have conducted extensive research. Traditional linear vibration energy harvesting systems, due to their narrow bandwidth, primarily limit energy harvesting to the resonance peak region. In contrast, nonlinear vibration energy harvesting systems exhibit significant advantages, including lower resonant frequencies, simpler structures, and higher output power. Among these, multistable nonlinear vibration energy harvesting systems are particularly noteworthy, as they can effectively harvest low-frequency broadband vibration energy. Given that vibrations in the natural environment are mostly random, multistable nonlinear vibration energy harvesting systems undoubtedly provide a powerful solution for improving the output performance of energy harvesters.

[0006] Chinese patent application number 202311445812.2 discloses a broadband low-frequency bistable triboelectric-piezoelectric-electromagnetic composite energy harvester and energy harvesting method. This device integrates three energy conversion mechanisms into a single energy harvester, improving energy conversion efficiency to some extent. However, the permanent magnet box experiences significant frictional force as it moves along a slide with built-in friction material, making it difficult for the piezoelectric beam to deform significantly under low-frequency vibrations, thus reducing the energy conversion efficiency of the piezoelectric component. Furthermore, the structural complexity increases the instability of the device, meaning there is a possibility of functional failure.

[0007] Chinese patent application number 202210066577.7 discloses a low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester. This device combines the energy conversion principles of piezoelectricity and electromagnetism, effectively improving energy conversion efficiency. However, its mass block is not very stable when moving up and down, which easily affects the deformation of the piezoelectric beam. At the same time, due to the presence of the sleeve, the mass block cannot move up and down significantly, preventing the piezoelectric beam from undergoing large deformation, resulting in low energy output efficiency of the piezoelectric plates on the piezoelectric beam.

[0008] To address the shortcomings of existing technologies, this invention ensures the stability of the mass block as it moves along the central support, while also allowing for significant movement of the mass block, increasing the deformation of the elastic beam and effectively improving energy conversion efficiency. This device has a simple structure and good stability, showing promising application prospects in the field of self-powering low-power electronic devices. Summary of the Invention

[0009] The technical problem to be solved by this utility model is how to broaden the resonant bandwidth of the piezoelectric energy harvesting device and improve the electrical energy output of the piezoelectric element. In order to overcome the above-mentioned defects of the prior art, this utility model provides a bistable piezoelectric energy harvesting device.

[0010] This invention provides a bistable piezoelectric energy harvesting device: it includes a base, on which a central support column perpendicular to the base is provided. A mass block is slidably mounted on the central support column. A plurality of piezoelectric elements are arranged circumferentially around the central support column as the axis. Each piezoelectric element includes a rigid beam and an elastic beam. One end of the rigid beam is hinged to one end of the elastic beam, and the other end of the rigid beam is hinged to the mass block. The other end of the elastic beam is connected to the base. A piezoelectric sheet is attached to the surface of the elastic beam. Under the excitation of the external environment, the mass block slides on the central support column. When the mass block slides, it drives the rigid beam to move, thereby causing the rigid beam to disturb the elastic beam and deform. The piezoelectric sheet deforms to generate electrical charge.

[0011] Compared with the prior art, this application has the following advantages: it employs a nonlinear bistable oscillation when the mass block slides along the central support, and the kinetic energy of the bistable oscillation is converted into electrical energy by the piezoelectric element, thus achieving the effect of bistable piezoelectric energy harvesting; at the same time, by hinged a rigid beam between the mass block and the elastic beam, the low-frequency resonant frequency band can be effectively widened, the compression deformation of the elastic beam by the rigid beam can be increased, and the problem of low power of a single traditional piezoelectric energy harvesting unit can be overcome, thereby greatly improving the broadband energy harvesting efficiency.

[0012] In one possible implementation, a mounting base is provided circumferentially on the end face of the base, the position and number of the mounting bases corresponding one-to-one with the piezoelectric elements, and the other end of the elastic beam is fixedly connected to the mounting base.

[0013] In one possible implementation, the mounting base is movably adjustable to the base, and the mounting base is adjustable radially along the base.

[0014] Compared with existing technologies, the technical effects achieved by adopting the above technical solution are as follows: when the mass block slides along the central support to two stable equilibrium states, it reaches the lowest point of potential energy, i.e., the potential well, and there is also a stable highest point of potential energy in the middle, i.e., the potential barrier. By moving and adjusting the mounting base to adjust the distance between the flexible beams, the distance between the potential barrier and the potential well is reduced, thereby realizing the generation of bistable transition oscillations under relatively small external excitation, widening the frequency band, and increasing the energy conversion efficiency. Furthermore, by adjusting the spacing of the elastic beams, the stiffness of the elastic beams can also be changed, thereby changing the resonant frequency to adapt to vibrations in complex environments.

[0015] In one possible implementation, the end face of the base is circumferentially provided with a mounting groove for mounting a mounting seat. The mounting groove is arranged radially along the base. An adjustment rail is provided at the bottom of the mounting groove, penetrating the base. The adjustment rail is arranged radially along the base. An adjustment hole is provided on the mounting seat. An adjustment bolt is passed through the adjustment hole. The adjustment bolt passes through the adjustment hole and the adjustment rail and is tightened with an adjustment nut to fix the mounting seat.

[0016] Compared with the existing technology, the technical effect achieved by adopting the above technical solution is: by loosening the adjusting nut and adjusting bolt, the adjusting mounting seat can be moved; when the mounting seat reaches the predetermined position, the adjusting nut can be tightened to fix the mounting seat; the above technical solution can move and adjust the mounting seat quickly and conveniently.

[0017] In one possible implementation, the mounting base is integrally provided with a connecting part, and the end of the elastic beam that connects to the base and the connecting part are respectively provided with connecting holes. The elastic beam and the connecting part are connected in series through connecting bolts and the connecting holes and fixedly connected with connecting nuts.

[0018] Compared with existing technologies, the above technical solution facilitates the assembly, replacement, and maintenance of piezoelectric components.

[0019] In one possible implementation, the rigid beam has a first connecting seat at each end, the elastic beam has a second connecting seat at the end that is hinged to the rigid beam, and the mass block has a third connecting seat. The first, second, and third connecting seats all have axial holes. The rigid beam and the elastic beam are pivotally connected by connecting the axial holes of the first and second connecting seats through a hinge shaft. The rigid beam and the mass block are pivotally connected by connecting the axial holes of the first and third connecting seats through a hinge shaft.

[0020] In one possible implementation, the base (1) is provided with a vibration mechanism, which is used to generate a vibration source to cause the mass block to resonate and slide up and down along the central support, causing the piezoelectric element to deform and generate electrical charge.

[0021] In one possible implementation, the mass block is a neodymium iron boron magnet, and a coil is provided inside the central support. The coil is electrically connected to a power source through a wire, so that the relative motion between the mass block and the coil cuts magnetic field lines to generate electromagnetic power.

[0022] In one possible implementation, the outer wall of the mass block is integrally formed with a connecting cross-section corresponding to each piezoelectric element, and the third connecting seat is disposed on the connecting cross-section. The mass block as a whole has a regular polyhedral structure, so that a bistable structure is formed between the mass, the piezoelectric element and the base, which helps to generate bistable oscillations.

[0023] In one possible implementation, the outer and inner surfaces of the piezoelectric element are connected to output wires for electrical energy output, and the output wires are electrically connected to a load or energy storage device. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a specific embodiment 1 of the present utility model;

[0025] Figure 2 This is an exploded view of the structure of a specific embodiment 1 of the present utility model;

[0026] Figure 3 This is a split schematic diagram of the piezoelectric element in specific embodiment 1 of this utility model;

[0027] Figure 4 This is a schematic diagram of the structure of a specific embodiment 2 of the present utility model;

[0028] Figure 5 This is a schematic diagram of the structure of the base and the central support in specific embodiment 2 of this utility model;

[0029] Figure 6 This is a schematic diagram of the mounting base in specific embodiment 2 of this utility model;

[0030] Figure 7 This is a schematic diagram of the central support and coil in a specific embodiment 3 of this utility model.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. Base; 2. Central support; 3. Mass block; 3.1. Connecting section; 4. Piezoelectric element; 4.1. Rigid beam; 4.2. Elastic beam; 5. Piezoelectric sheet; 6. Mounting seat; 6.1. Connecting part; 7. Mounting groove; 8. Adjusting track; 9. Adjusting bolt; 10. Adjusting nut; 11. Adjusting hole; 12. Connecting hole; 13. First connecting seat; 14. Second connecting seat; 15. Third connecting seat; 16. Coil. Detailed Implementation

[0033] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0034] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0035] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0036] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0037] Example 1:

[0038] like Figures 1-3A bistable piezoelectric energy harvesting device is shown, comprising a base 1, a central support 2 perpendicular to the base 1, a mass block 3 slidably mounted on the central support 2, and a plurality of piezoelectric elements 4 arranged circumferentially around the central support 2. The number of piezoelectric elements 4 is at least two, and when there are two piezoelectric elements 4, they are symmetrically arranged to achieve a bistable oscillation effect. In this specific embodiment, the number of piezoelectric elements 4 is eight. Figure 1 As shown, a mounting base 6 is circumferentially fixed on the end face of the base 1. The position of the mounting base 6 corresponds one-to-one with the position of the piezoelectric element 4. The piezoelectric element 4 includes a rigid beam 4.1 and an elastic beam 4.2. One end of the rigid beam 4.1 is hinged to one end of the elastic beam 4.2, and the other end of the rigid beam 4.1 is hinged to the mass block 3. The other end of the elastic beam 4.2 is fixedly connected to the mounting base 6. A piezoelectric sheet 5 is attached to the surface of the elastic beam 4.2. A vibration mechanism for generating vibration is provided on the base 1. In this specific embodiment, the vibration mechanism is an exciter. The exciter vibrates and excites the mass block 3 to slide left and right along the central support column 2. When the mass block 3 slides, it drives the rigid beam 4.1 to move, thereby causing the rigid beam 4.1 to push the elastic beam 4.2 to deform. The piezoelectric sheet 5 deforms to generate electrical charge.

[0039] The outer wall of the mass block 3 is integrally formed with a connecting facet 3.1 corresponding to each piezoelectric element 4. The third connecting seat 15 is disposed on the connecting facet 3.1. The mass block 3 has a regular polyhedral structure, which forms a bistable structure between the mass, the piezoelectric element 4 and the base 1, which helps to generate bistable oscillations.

[0040] The specific structure connecting the mass block 3, the rigid beam 4.1, and the elastic beam 4.2 is as follows: the two ends of the rigid beam 4.1 are respectively provided with a first connecting seat 13; the end of the elastic beam 4.2 that is hinged to the rigid beam 4.1 is provided with a second connecting seat 14; the mass block 3 is provided with a third connecting seat 15; the first connecting seat 13, the second connecting seat 14, and the third connecting seat 15 are all provided with axial holes; the rigid beam 4.1 and the elastic beam 4.2 are pivotally connected by connecting the axial holes of the first connecting seat 13 and the second connecting seat 14 through a hinge shaft; the rigid beam 4.1 and the mass block 3 are pivotally connected by connecting the axial holes of the first connecting seat 13 and the third connecting seat 15 through a hinge shaft.

[0041] The specific structure for the fixed connection between the elastic beam 4.2 and the mounting base 6 is as follows: the mounting base 6 is integrally provided with a connecting part 6.1, and the end of the elastic beam 4.2 that connects to the base 1 and the connecting part 6.1 are respectively provided with connecting holes 12. The elastic beam 4.2 and the connecting part 6.1 are connected in series through connecting bolts and the connecting holes 12 and fixedly connected with connecting nuts.

[0042] In addition, the outer and inner surfaces of the piezoelectric element 5 are connected to output wires for electrical energy output, and the output wires are electrically connected to a load or energy storage device.

[0043] Example 2:

[0044] like Figure 4-6 As shown, this specific embodiment adds the following to specific embodiment 1: the mounting base 6 is movably and adjustablely connected to the base 1, and the mounting base 6 can be adjusted radially along the base 1. The structure for adjusting the mounting base 6 radially along the base 1 in this specific embodiment is as follows: the end face of the base 1 is circumferentially provided with a mounting groove 7 for mounting the mounting base 6, the mounting groove 7 is radially arranged along the base 1, the bottom of the mounting groove 7 is provided with an adjustment track 8 penetrating the base 1, the adjustment track 8 is radially arranged along the base 1, the mounting base 6 is provided with an adjustment hole 11, an adjustment bolt 9 is threaded through the adjustment hole 11, the adjustment bolt 9 passes through the adjustment hole 11 and the adjustment track 8 and is tightened with an adjustment nut 10 to fix the mounting base 6.

[0045] As is well known, when the mass block 3 slides along the central support 2 to two stable equilibrium states, it reaches the lowest point of potential energy, i.e., the potential well, and there is also a stable highest point of potential energy in the middle, i.e., the potential barrier.

[0046] By loosening the adjusting nut 10 and adjusting bolt 9, the adjusting mounting base 6 can be moved. Once the mounting base 6 reaches the predetermined position, tightening the adjusting nut 10 will fix the mounting base 6. This technical solution allows for quick and convenient movement and adjustment of the mounting base 6. Moving the adjusting mounting base 6 adjusts the distance between the flexible beams, thereby reducing the distance between the potential barrier and the potential well, enabling bistable transition oscillations under relatively small external excitations, widening the frequency band, and increasing energy conversion efficiency. Furthermore, adjusting the spacing of the elastic beams 4.2 can change the stiffness of the elastic beams 4.2, thus altering the resonant frequency to adapt to vibrations in complex environments.

[0047] Example 3:

[0048] like Figure 7 As shown, the difference between this specific embodiment and specific embodiments 1 and 2 is that the mass block 3 is a neodymium iron boron magnetic block, the interior of the central support 2 is a cavity, the cavity is provided with a coil 16, and the two ends of the central support 2 are respectively provided with through holes. The coil 16 is electrically connected to the positive and negative poles of the external power supply through wires passing through the through holes, so that the relative motion between the mass block 3 and the coil 16 cuts the magnetic field lines to form electromagnetic power generation.

[0049] In the description of the embodiments of this application, it should be noted that the terms "inner" and "outer" and other terms indicating direction or positional relationship are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0050] In the description of this application, the references to terms such as "an embodiment," "some embodiments," "in this embodiment," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0051] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A bistable piezoelectric energy harvesting device, comprising a base (1), characterized in that, The base (1) is provided with a central support column (2) perpendicular to it. A mass block (3) is slidably mounted on the central support column (2). A number of piezoelectric elements (4) are arranged circumferentially around the central support column (2) with the central support column (2) as the axis. The piezoelectric element (4) includes a rigid beam (4.1) and an elastic beam (4.2). One end of the rigid beam (4.1) is hinged to one end of the elastic beam (4.2). The other end of the rigid beam (4.1) is hinged to the mass block (3). The other end of the elastic beam (4.2) is connected to the base (1). A piezoelectric sheet (5) is attached to the surface of the elastic beam (4.2). Under the excitation of the external environment, the mass block (3) slides on the central support column (2). When the mass block (3) slides, it drives the rigid beam (4.1) to move, thereby causing the rigid beam (4.1) to push the elastic beam (4.2) to deform. The piezoelectric sheet (5) deforms to generate electric charge.

2. The bistable piezoelectric energy harvesting device according to claim 1, characterized in that, The end face of the base (1) is provided with a mounting seat (6) in the circumferential direction. The position and number of the mounting seats (6) correspond one-to-one with the piezoelectric elements (4). The other end of the elastic beam (4.2) is fixedly connected to the mounting seat (6).

3. The bistable piezoelectric energy harvesting device according to claim 2, characterized in that, The mounting base (6) is movably and adjustablely connected to the base (1), and the mounting base (6) can be moved and adjusted radially along the base (1).

4. The bistable piezoelectric energy harvesting device according to claim 3, characterized in that, The end face of the base (1) is circumferentially provided with a mounting groove (7) for mounting a mounting seat (6). The mounting groove (7) is arranged radially along the base (1). The bottom of the mounting groove (7) is provided with an adjustment track (8) that passes through the base (1). The adjustment track (8) is arranged radially along the base (1). The mounting seat (6) is provided with an adjustment hole (11). An adjustment bolt (9) is passed through the adjustment hole (11). The adjustment bolt (9) passes through the adjustment hole (11), the adjustment track (8), and is tightened with an adjustment nut (10) to fix the mounting seat (6).

5. The bistable piezoelectric energy harvesting device according to claim 2, 3, or 4, characterized in that, The mounting base (6) is integrally provided with a connecting part (6.1). The end of the elastic beam (4.2) connected to the base (1) and the connecting part (6.1) are respectively provided with connecting holes (12). The elastic beam (4.2) and the connecting part (6.1) are connected in series through the connecting bolts and the connecting holes (12) and fixedly connected with the connecting nut.

6. The bistable piezoelectric energy harvesting device according to claim 5, characterized in that, The rigid beam (4.1) is provided with a first connecting seat (13) at both ends, the elastic beam (4.2) is provided with a second connecting seat (14) at the end that is hinged to the rigid beam (4.1), and the mass block (3) is provided with a third connecting seat (15). The first connecting seat (13), the second connecting seat (14) and the third connecting seat (15) are all provided with axial holes. The rigid beam (4.1) and the elastic beam (4.2) can be pivotally connected by connecting the axial holes of the first connecting seat (13) and the second connecting seat (14) through a hinge shaft. The rigid beam (4.1) and the mass block (3) can be pivotally connected by connecting the axial holes of the first connecting seat (13) and the third connecting seat (15) through a hinge shaft.

7. The bistable piezoelectric energy harvesting device according to claim 1, characterized in that, The base (1) is provided with a vibration mechanism, which is used to generate a vibration source to make the mass block resonate and slide up and down along the central support, causing the piezoelectric element to deform and generate electrical charge.

8. The bistable piezoelectric energy harvesting device according to claim 1, characterized in that, The mass block (3) is a neodymium iron boron magnet, and the central support (2) is equipped with a coil (16), which is electrically connected to the power supply through a wire.

9. The bistable piezoelectric energy harvesting device according to claim 7 or 8, characterized in that, The outer wall of the mass block (3) is integrally formed with a connecting facet (3.1) corresponding to each piezoelectric element (4), and the third connecting seat (15) is provided on the connecting facet (3.1). The mass block (3) as a whole has a regular polyhedral structure.

10. The bistable piezoelectric energy harvesting device according to claim 9, characterized in that, The outer and inner surfaces of the piezoelectric sheet (5) are connected to output wires for power output, and the output wires are electrically connected to a load or energy storage device.

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