Bilateral clamping cantilever beam type energy collector and use method

Abstract

The invention relates to the technical field of renewable energy sources, and discloses a double-side clamping cantilever beam type energy collector and a use method.The upper end face and the lower end face of a cantilever beam are each provided with a piezoelectric body, a double-wafer multi-layer structure of a piezoelectric layer, a substrate layer and a piezoelectric layer is formed, and then a double-side clamping and fixing structure is adopted; when mechanical vibration exists in an external environment, the double-side clamping cantilever beam type energy collector induces the vibration and then enables inertia force to act on the piezoelectric body, so that the piezoelectric body is bent and deformed, and a charge signal which is in a certain proportion to the input acceleration is generated on the surface of the piezoelectric body based on the direct piezoelectric effect; and the working frequency band of the energy collector is further expanded.

Description

Technical Field

[0001] The invention relates to the technical field of renewable energy, and in particular to a double-sided clamped cantilever beam energy collector and a use method thereof. Background Art

[0002] With the development of science and technology, large-scale integrated circuit technology has made great progress. The development of these technologies can make the size and structure of some special electronic devices (such as wireless sensors, implantable electronic devices, etc.) very small. At present, most micro electronic devices are powered by batteries, so when the battery runs out, it is necessary to constantly replace the battery. In fact, the working environment of these micro low-power electronic devices is mostly very complex, and the micro low-power devices in these environments do not have the conditions for frequent battery replacement. Therefore, people pay more and more attention to the development of ways to obtain some energy from the surrounding environment, convert vibration energy into electrical energy, and provide energy supplement for electronic devices.

[0003] Piezoelectric energy harvesting is currently the most widely used and simplest energy harvesting method. It uses external environmental excitation, such as vibration, to deform the piezoelectric material, and uses the positive piezoelectric effect to finally obtain the output alternating current. Piezoelectric energy harvesting has many advantages that can be used, such as no external power supply, simple structure and easy to make (cantilever beam), high output, and good compatibility with micro-electromechanical system processes. However, piezoelectric vibration energy harvesters currently have many limitations, which limit their scope of application, including narrow operating frequency band and low output voltage. On the one hand, these lead to great restrictions on the environment and frequency range in which piezoelectric energy harvesters can be used, making it difficult to use in some special environments; on the other hand, too low output voltage requires the design of complex circuits for optimization, resulting in the complexity of the entire energy harvesting system. The above problems have limited the popularity of piezoelectric energy harvesters and need to be solved urgently. Summary of the invention

[0004] The invention provides a double-sided clamped cantilever beam type energy collector and a use method thereof, which solves the technical problem of narrow working frequency band of the existing energy collector.

[0005] A first aspect of the present invention provides a double-sided clamped cantilever beam type energy collector, comprising a cantilever beam;

[0006] Both ends of the cantilever beam are fixedly connected to a fixed base;

[0007] The upper end surface and the lower end surface of the cantilever beam are both installed with a piezoelectric body, and the piezoelectric body is used to generate electric energy by deforming through the bending vibration of the cantilever beam, and is used to extract the electric energy.

[0008] Optionally, the piezoelectric bodies mounted on two end surfaces of the cantilever beam have opposite polarization directions.

[0009] Optionally, the piezoelectric bodies mounted on two end surfaces of the cantilever beam are made of the same piezoelectric body material.

[0010] Optionally, a ground electrode layer is provided on one side of the piezoelectric body close to the cantilever beam;

[0011] A positive output electrode layer is arranged on a side of the piezoelectric body away from the cantilever beam.

[0012] Optionally, the piezoelectric body is a long strip-shaped piezoelectric body.

[0013] Optionally, the piezoelectric body is bonded and fixed to the cantilever beam by epoxy resin.

[0014] Optionally, the material of the piezoelectric body is any one of indium-doped lead magnesium niobate-lead titanate single crystal, PMNT textured ceramic and lead zirconate titanate ceramic.

[0015] Optionally, the fixed base is an H-shaped fixed base;

[0016] The fixed base includes a first vertical member, a second vertical member and a horizontal member;

[0017] The first vertical member is fixedly connected to the second vertical member through the horizontal member.

[0018] Optionally, threaded holes are provided at both ends of the cantilever beam;

[0019] One end of the cantilever beam is threadedly connected to the top of the first vertical member through a bolt;

[0020] The other end of the cantilever beam is threadedly connected to the top of the second vertical member through a bolt.

[0021] A second aspect of the present invention provides a method for using the bilaterally clamped cantilever beam energy collector, comprising:

[0022] The two ends of the cantilever beam are fixed on a fixed base, and a piezoelectric body is installed on the upper end surface and the lower end surface of the cantilever beam;

[0023] When the cantilever beam is subjected to external excitation and generates bending vibration, the piezoelectric body on the upper end surface and the piezoelectric body on the lower end surface are deformed simultaneously, generating electric energy and conducting it out.

[0024] It can be seen from the above technical solutions that the present invention has the following advantages:

[0025] In the present invention, both ends of the cantilever beam are fixed on a fixed base, and piezoelectric bodies are installed on the upper and lower end surfaces of the cantilever beam; when the cantilever beam is subjected to external excitation to generate bending vibration, the piezoelectric bodies on the upper and lower end surfaces are deformed at the same time, generating electric energy and conducting it out; the present invention installs piezoelectric bodies on the upper and lower end surfaces of the cantilever beam to form a double-chip multi-layer structure of piezoelectric layer-substrate layer-piezoelectric layer, and then adopts a double-sided clamping and fixing structure. When there is mechanical vibration in the external environment, the double-sided clamped cantilever beam energy collector senses the vibration and causes the inertial force to act on the piezoelectric body, thereby causing it to bend and deform, and based on the positive piezoelectric effect, a charge signal that is proportional to the input acceleration is generated on the surface of the piezoelectric body, further broadening the working frequency band of the energy collector. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0027] Figure 1 It is a schematic structural diagram of a double-sided clamped cantilever beam energy collector according to an embodiment of the present invention;

[0028] Figure 2 A schematic diagram of the connection structure between the piezoelectric body and the cantilever beam according to an embodiment of the present invention;

[0029] Figure 3 A schematic diagram of a cantilever beam structure with single-side clamping according to an embodiment of the present invention;

[0030] Figure 4 It is a schematic diagram of a cantilever beam structure with double-sided clamping according to an embodiment of the present invention;

[0031] Figure 5 It is a structural schematic diagram of a single-side clamped cantilever beam type energy collector according to an embodiment of the present invention;

[0032] Figure 6 A schematic diagram showing performance comparison of different piezoelectric materials according to an embodiment of the present invention;

[0033] Figure 7 A schematic diagram of an impedance curve of a free-state single-side clamped cantilever beam energy harvester using a piezoelectric body made of an indium-doped lead magnesium niobate-lead titanate single crystal material polarized along the

[011] direction according to an embodiment of the present invention;

[0034] Figure 8A schematic diagram of an impedance curve of a free state of a single-side clamped cantilever beam type energy harvester using a piezoelectric body of an indium-doped lead magnesium niobate-lead titanate single crystal polarized along the

[001] direction according to an embodiment of the present invention;

[0035] Fig. 9 It is a schematic diagram of an impedance curve of a single-side clamped cantilever beam type energy harvester in a free state using a piezoelectric body of PMNT textured ceramics according to an embodiment of the present invention;

[0036] Fig.10 It is a schematic diagram of an impedance curve of a single-side clamped cantilever beam type energy harvester in a free state using a piezoelectric body of lead zirconate titanate ceramic according to an embodiment of the present invention;

[0037] Fig.11 A schematic diagram of an impedance curve of a single-side clamped cantilever beam type energy harvester in a clamped state using a piezoelectric body made of an indium-doped lead magnesium niobate-lead titanate single crystal material polarized along the

[011] direction according to an embodiment of the present invention;

[0038] Fig.12 A schematic diagram of an impedance curve of a single-side clamped cantilever beam type energy harvester in a clamped state using a piezoelectric body of an indium-doped lead magnesium niobate-lead titanate single crystal polarized along the

[001] direction according to an embodiment of the present invention;

[0039] Fig.13 It is a schematic diagram of an impedance curve of a single-side clamped cantilever beam type energy collector of a piezoelectric body using PMNT textured ceramics in a clamped state according to an embodiment of the present invention;

[0040] Fig.14 It is a schematic diagram of an impedance curve of a single-side clamped cantilever beam type energy harvester in a clamped state using a piezoelectric body of lead zirconate titanate ceramic according to an embodiment of the present invention;

[0041] Fig.15 A schematic diagram of the relationship between the output voltage and frequency of a single-side clamped cantilever beam energy harvester according to an embodiment of the present invention;

[0042] Fig.16 A schematic diagram of the relationship between the output voltage and acceleration of a single-side clamped cantilever beam energy harvester according to an embodiment of the present invention;

[0043] Fig.17 A schematic diagram of an impedance curve of a double-sided clamped cantilever beam type energy harvester in a free state using a piezoelectric body made of an indium-doped lead magnesium niobate-lead titanate single crystal material polarized along the

[011] direction according to an embodiment of the present invention;

[0044] Fig.18A schematic diagram of an impedance curve in a free state of a double-sided clamped cantilever beam type energy harvester using a piezoelectric body of an indium-doped lead magnesium niobate-lead titanate single crystal polarized along the

[001] direction according to an embodiment of the present invention;

[0045] Fig.19 It is a schematic diagram of an impedance curve of a double-sided clamped cantilever beam type energy harvester in a free state using a piezoelectric body of PMNT textured ceramics according to an embodiment of the present invention;

[0046] Fig. 20 It is a schematic diagram of an impedance curve of a double-sided clamped cantilever beam type energy harvester in a free state using a piezoelectric body of lead zirconate titanate ceramic according to an embodiment of the present invention;

[0047] Fig.21 A schematic diagram of an impedance curve of a double-sided clamped cantilever beam type energy harvester in a clamped state using a piezoelectric body made of an indium-doped lead magnesium niobate-lead titanate single crystal material polarized along the

[011] direction according to an embodiment of the present invention;

[0048] Fig. 22 A schematic diagram of an impedance curve of a double-sided clamped cantilever beam type energy harvester in a clamped state using a piezoelectric body of an indium-doped lead magnesium niobate-lead titanate single crystal polarized along the

[001] direction according to an embodiment of the present invention;

[0049] Fig.23 It is a schematic diagram of an impedance curve of a double-sided clamped cantilever beam type energy collector of a piezoelectric body using PMNT textured ceramics in a clamped state according to an embodiment of the present invention;

[0050] Fig.24 It is a schematic diagram of an impedance curve of a double-sided clamped cantilever beam type energy harvester in a clamped state using a piezoelectric body of lead zirconate titanate ceramic according to an embodiment of the present invention;

[0051] Fig.25 A schematic diagram of the relationship between the output voltage and frequency of the double-sided clamped cantilever beam energy harvester according to an embodiment of the present invention;

[0052] Fig.26 A schematic diagram of the relationship between the output voltage and acceleration of a double-sided clamped cantilever beam energy harvester according to an embodiment of the present invention;

[0053] Fig. 27 A flowchart of the steps of a method for using a double-sided clamped cantilever beam energy collector according to an embodiment of the present invention;

[0054] The meanings of the reference numerals are as follows:

[0055] 101, piezoelectric body; 102, cantilever beam; 103, bolt; 104, fixed base; 201, positive output electrode layer; 202, ground electrode layer. DETAILED DESCRIPTION

[0056] The embodiment of the present invention provides a double-sided clamped cantilever beam energy collector and a use method thereof, which are used to solve the technical problem of narrow operating frequency band of existing energy collectors.

[0057] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] See also Figure 1 and Figure 2 , a bilaterally clamped cantilever beam type energy collector provided by the present invention comprises a cantilever beam 102;

[0059] Both ends of the cantilever beam 102 are fixedly connected to a fixed base 104;

[0060] The upper end surface and the lower end surface of the cantilever beam 102 are both mounted with a piezoelectric body 101 . The piezoelectric body 101 is used to generate electric energy by deforming through the bending vibration of the cantilever beam 102 , and is used to extract the electric energy.

[0061] In an embodiment of the present invention, both ends of the cantilever beam 102 are fixed on a fixed base 104, and a piezoelectric body 101 is installed on the upper end face and the lower end face of the cantilever beam 102; when the cantilever beam 102 is subjected to external excitation to generate bending vibration, the piezoelectric body 101 on the upper end face and the piezoelectric body 101 on the lower end face are deformed at the same time, generating electric energy and conducting it out; the present invention installs a piezoelectric body 101 on the upper end face and the lower end face of the cantilever beam 102 to form a double-chip multi-layer structure of a piezoelectric layer-substrate layer-piezoelectric layer, and then adopts a bilateral clamping and fixing structure. When there is mechanical vibration in the external environment, the bilaterally clamped cantilever beam energy collector senses the vibration and causes the inertial force to act on the piezoelectric body 101, thereby causing it to bend and deform, and based on the positive piezoelectric effect, a charge signal that is proportional to the input acceleration is generated on the surface of the piezoelectric body 101, further broadening the working frequency band of the energy collector.

[0062] It should be noted that the dual-chip multilayer structure design of piezoelectric layer-substrate layer-piezoelectric layer adopts a connection mode of mechanical series connection and electrical parallel connection.

[0063] It should be noted that the piezoelectric layer-substrate layer-piezoelectric layer refers to the piezoelectric body 101 -cantilever beam 102 -piezoelectric body 101 .

[0064] Mechanical series connection: In a dual-chip multilayer structure, mechanical series connection means that the two piezoelectric layers and the middle substrate layer are mechanically connected in sequence, like links in a chain. When the structure is subjected to external forces generated by external excitation, such as pressure or tension, the force is transmitted through each layer in sequence.

[0065] Electrical parallel connection: means that the two piezoelectric layers are electrically connected in parallel. When the piezoelectric layers generate charges due to mechanical deformation, the charges generated by the two piezoelectric layers can simultaneously provide electrical energy to the external circuit. For example, if the upper piezoelectric layer generates positive charges due to pressure, the lower piezoelectric layer also generates charges (according to the piezoelectric effect). These charges will converge into the external circuit at the same time, just like two batteries connected in parallel to power the circuit.

[0066] See also Figure 1 and Figure 2 The present invention provides a double-sided clamped cantilever beam type energy collector, in which the polarization directions of the piezoelectric bodies 101 installed on the two end surfaces of the cantilever beam 102 are opposite.

[0067] In the embodiment of the present invention, the polarization directions of the piezoelectric body 101 installed on the two end faces of the cantilever beam 102 are opposite. When external excitation causes the bending vibration of the cantilever beam 102, the bending vibration causes the piezoelectric body 101 close to the cantilever beam 102 to deform in the length direction. The piezoelectric body 101 on one side of the same cantilever beam 102 shrinks in the length direction, and the piezoelectric body 101 on the other side stretches in the length direction. The deformation of the piezoelectric body 101 makes the center of gravity of the positive and negative charges no longer coincide, and the total electric moment of the piezoelectric body 101 is no longer zero, causing the surface of the piezoelectric body 101 to be charged. Finally, the piezoelectric body 101 generates an output voltage, and then the electrical energy can be exported. That is, the energy collection process of converting the mechanical energy of the external excitation into electrical energy is completed.

[0068] See also Figure 1 and Figure 2 The present invention provides a double-sided clamped cantilever beam type energy collector, in which the piezoelectric bodies 101 installed on the two end surfaces of the cantilever beam 102 are made of the same material.

[0069] In the embodiment of the present invention, the piezoelectric bodies 101 installed on the two end surfaces of the cantilever beam 102 are made of the same material, which can ensure the consistency of electrical performance and the coordination of mechanical performance.

[0070] The consistency of electrical performance includes: the synergy of the piezoelectric effect and the matching of voltage and current output;

[0071] Synergy of piezoelectric effect: When the cantilever beam 102 vibrates, the piezoelectric body 101 installed on its two end faces will convert mechanical energy into electrical energy based on the piezoelectric effect. If the material of the piezoelectric body 101 is the same, then under the same mechanical stress, according to the piezoelectric equation D=dT+εTE (where D is the electric displacement vector, d is the piezoelectric strain constant, T is the stress tensor, εT is the dielectric constant under constant stress, and E is the electric field intensity vector), charges of the same type and size ratio will be generated. This helps to collect charges and convert electrical energy according to the expected electrical laws when connected in parallel or series, avoiding electrical performance mismatches caused by different materials.

[0072] Matching of voltage and current output: Piezoelectric bodies 101 of the same material will produce similar voltage and current output characteristics under the same mechanical vibration excitation. In the case of electrical parallel connection, piezoelectric bodies 101 of the same material produce the same voltage and current can be superimposed, thereby improving the overall power output capacity.

[0073] The coordination of mechanical properties includes coupling effect and thermal expansion matching with the cantilever beam 102;

[0074] Coupling effect with the cantilever beam 102: During the vibration of the cantilever beam 102, the piezoelectric body 101 at both end faces needs to have good mechanical coupling with the cantilever beam 102. The materials of the same piezoelectric body 101 usually have similar mechanical performance parameters such as elastic modulus. This makes the connection between the piezoelectric body 101 and the cantilever beam 102 more mechanically coordinated, and can better deform in accordance with the vibration of the cantilever beam 102, thereby effectively converting the mechanical energy of the cantilever beam 102 into electrical energy.

[0075] Thermal expansion matching: Under different working temperature environments, the piezoelectric body 101 of the same material has the same thermal expansion coefficient. When the temperature changes, the piezoelectric body 101 of the same material will expand or contract at the same ratio, avoiding problems such as structural deformation, cracking or piezoelectric performance degradation caused by thermal expansion differences, and ensuring the stability of the cantilever beam 102-piezoelectric body 101 structure.

[0076] See also Figure 2 The present invention provides a double-sided clamped cantilever beam type energy collector, wherein a ground electrode layer 202 is provided on one side of the piezoelectric body 101 close to the cantilever beam 102;

[0077] A positive output electrode layer 201 is disposed on a side of the piezoelectric body 101 away from the cantilever beam 102 .

[0078] It should be noted that two electrode layers are arranged on both sides of the piezoelectric body 101. The piezoelectric body 101 is provided with a ground electrode layer 202 close to the cantilever beam 102, and a positive output electrode layer 201 is arranged away from the cantilever beam 102. When the piezoelectric body 101 is subjected to mechanical stress and generates charges, the ground electrode layer 202 helps to maintain the balance of the charges. A portion of the charges will flow in or out through the ground electrode layer 202 to maintain the electrical balance of the entire circuit. The positive output electrode layer 201 is away from the cantilever beam 102, and its main function is to collect the positive charges generated by the piezoelectric body 101 when subjected to mechanical stress, and output these charges to the external circuit.

[0079] See also Figure 1 and Figure 2 The present invention provides a double-sided clamped cantilever beam energy collector, wherein the piezoelectric body 101 is a long strip-shaped piezoelectric body 101.

[0080] It should be noted that the piezoelectric body 101 of the present invention is a long strip piezoelectric body 101, and the long strip refers to a shape in which the length is much greater than the width, wherein the long strip piezoelectric body is specifically a rod-shaped piezoelectric body 101 or a slender sheet-shaped piezoelectric body 101. Therefore, the piezoelectric body 101 uses a length direction vibration mode, and the output performance is closely related to the piezoelectric constant of the piezoelectric body 101. For the piezoelectric body 101, when the length direction vibration mode is selected, it means that when stress or electric field is applied in the length direction, the piezoelectric body 101 will mainly vibrate or deform along the length direction. This vibration mode is determined by factors such as the crystal structure and polarization direction of the piezoelectric material. For example, when a pressure is applied in the length direction of a long strip of piezoelectric material, the electric domain inside the material will change accordingly, thereby generating an electrical response related to the length direction.

[0081] Furthermore, the piezoelectric constant is an important parameter for describing the performance of piezoelectric materials. When the piezoelectric body 101 is in a longitudinal vibration mode, its output performance (such as the amount of charge generated, voltage, etc.) is closely related to the piezoelectric constant. For example, in a piezoelectric sensor, if the piezoelectric constant of the piezoelectric body 101 is d31, when it is subjected to a certain pressure F, according to the piezoelectric equation Q=d31F (Q is the amount of charge generated), a larger piezoelectric constant will generate more charge, thereby affecting the output performance indicators such as the sensitivity of the sensor. Similarly, in a piezoelectric energy harvesting device, a larger piezoelectric constant d31 also means that more electrical energy can be collected under the same mechanical vibration (along the length direction).

[0082] See also Figure 1 and Figure 2 The present invention provides a double-sided clamped cantilever beam energy collector, in which the piezoelectric body 101 is fixed to the cantilever beam 102 by gluing epoxy resin.

[0083] It should be noted that the piezoelectric body 101 is fixed to the cantilever beam 102 by pasting epoxy resin. The epoxy resin has excellent bonding properties and can firmly paste the piezoelectric body 101 on both sides of the cantilever beam 102. At the same time, the epoxy resin can effectively transfer stress. When the cantilever beam 102 is subjected to external excitation and bends and vibrates, the stress can be transferred to the piezoelectric body 101 through the epoxy resin layer. Since the epoxy resin has good bonding with the piezoelectric body 101 and the cantilever beam 102, the loss during the stress transfer process is small. This enables the piezoelectric body 101 to accurately sense the deformation of the cantilever beam 102, thereby generating corresponding charges according to the piezoelectric effect, thereby improving the efficiency of energy conversion or sensing. Moreover, epoxy resin is also a good electrical insulator. When the piezoelectric body 101 is pasted on the cantilever beam 102, unnecessary electrical short circuits between the piezoelectric body 101 and the cantilever beam 102 can be prevented.

[0084] See also Figure 1-Figure 26 The present invention provides a double-sided clamped cantilever beam energy collector, wherein the material of the piezoelectric body 101 is any one of an indium-doped lead magnesium niobate-lead titanate single crystal polarized along the

[011] direction, an indium-doped lead magnesium niobate-lead titanate single crystal polarized along the

[001] direction, a PMNT textured ceramic, and a lead zirconate titanate ceramic.

[0085] It should be noted that the piezoelectric material of the piezoelectric body 101 of the present invention is preferably any one of indium-doped lead magnesium niobate-lead titanate single crystal, PMNT textured ceramics and lead zirconate titanate ceramics.

[0086] The indium-doped lead magnesium niobate-lead titanate single crystal includes an indium-doped lead magnesium niobate-lead titanate single crystal polarized along the

[011] direction and an indium-doped lead magnesium niobate-lead titanate single crystal polarized along the

[001] direction. That is, the piezoelectric material of the piezoelectric body 101 is preferably any one of an indium-doped lead magnesium niobate-lead titanate single crystal polarized along the

[011] direction, an indium-doped lead magnesium niobate-lead titanate single crystal polarized along the

[001] direction, a PMNT textured ceramic, and a lead zirconate titanate ceramic.

[0087] The indium-doped lead magnesium niobate-lead titanate single crystal polarized along the

[011] direction is a

[011] -polarized PIN-PMN-PT single crystal.

[0088] The indium-doped lead magnesium niobate-lead titanate single crystal polarized along the

[001] direction is a

[001] -polarized PIN-PMN-PT single crystal.

[0089] Lead zirconate titanate ceramics are commercial ceramics PZT-5.

[0090] It is worth mentioning that the cantilever beam 102 is made of silicon-based materials, specifically single-crystal silicon or polycrystalline silicon. Single-crystal silicon has excellent mechanical properties, and its elastic modulus is relatively high, and it can produce large stress under small deformation. This makes the single-crystal silicon cantilever beam 102 sensitive to small changes in physical quantities (such as pressure, acceleration, etc.) in the micro-electromechanical system (MEMS) sensor based on the cantilever beam 102. The preparation process of polycrystalline silicon is relatively simple and the cost is relatively low compared to single-crystal silicon. In some large-scale MEMS products that are more sensitive to cost, the polycrystalline silicon cantilever beam 102 is a feasible choice.

[0091] In an alternative embodiment of the present invention, the piezoelectric body 101 adopts a dual-chip structure, and can be composed of two layers of identical chip layers, specifically including two piezoelectric chip layers, that is, it can be understood that the piezoelectric layer includes two piezoelectric chip layers. Therefore, the piezoelectric body 101 arranged on the cantilever beam 102 is arranged from top to bottom as a positive output electrode layer 201, two piezoelectric chip layers and a ground electrode layer 202, wherein it should be noted that the piezoelectric chip layer is any one of a

[011] -direction polarized PIN-PMN-PT single crystal, a

[001] -direction polarized PIN-PMN-PT single crystal, a PMNT textured ceramic and a commercial ceramic PZT-5. When two layers of identical chip layers are used, when mechanical energy (such as vibration energy) in the external environment acts on the dual-chip structure, due to the synergistic effect of the two piezoelectric chips, more charges can be generated compared to a single piezoelectric chip structure. At the same time, due to the mutual cooperation and support of the two chips, it can better adapt to this irregular vibration, making the energy output more stable, reducing the fluctuation in the energy collection process, and improving the reliability of energy collection.

[0092] In another alternative embodiment of the present invention, the piezoelectric body 101 adopts a dual-chip structure, and can be composed of two different chip layers, specifically including a piezoelectric chip layer and an elastic chip layer, that is, it can be understood that the piezoelectric layer includes a piezoelectric chip layer and an elastic chip layer. Therefore, the piezoelectric body 101 arranged on the cantilever beam 102 is arranged from top to bottom as a positive output electrode layer 201, a piezoelectric chip layer, an elastic chip layer and a ground electrode layer 202, wherein it should be noted that the piezoelectric chip layer is any one of a

[011] -polarized PIN-PMN-PT single crystal, a

[001] -polarized PIN-PMN-PT single crystal, a PMNT textured ceramic and a commercial ceramic PZT-5. When two different chip layers are used, when there is a vibration source in the outside world, the elastic chip layer can transfer the vibration energy to the piezoelectric chip layer in a suitable manner like a spring, so that the piezoelectric chip layer can better respond to changes in mechanical energy. At the same time, the elastic wafer layer can also play a buffering role, preventing the piezoelectric wafer layer from being damaged by excessive impact force, thereby ensuring the continuous and stable progress of the energy conversion process. The piezoelectric wafer layer generates electric charge according to the piezoelectric effect; therefore, the elastic wafer layer provides support and protection for the piezoelectric wafer layer. Under complex environmental conditions, such as in an environment with impact, irregular vibration or temperature changes, the elastic wafer layer can maintain the integrity of the entire structure, allowing the energy harvester to work stably, reducing the risk of energy collection interruption due to structural damage, thereby improving the reliability of energy collection.

[0093] In the embodiment of the present invention, the piezoelectric material is sequentially subjected to the steps of orientation, cutting, grinding, gold spraying to prepare electrodes, polarization, etc., so as to obtain a piezoelectric body 101 with the required size and performance.

[0094] See also Figure 1-Figure 5 As shown, two clamping methods, bilateral clamping and unilateral clamping, are provided. For the piezoelectric material of the above-mentioned piezoelectric body 101, the performance comparison between the materials of different piezoelectric bodies 101, and the fact that bilateral clamping has a wider frequency band than unilateral clamping will be provided in detail in the following two specific test examples.

[0095] Test Example 1

[0096] This experimental example provides four different materials for the piezoelectric body 101, namely,

[011] -direction polarized PIN-PMN-PT single crystal,

[001] -direction polarized PIN-PMN-PT single crystal, PMNT textured ceramic, and commercial ceramic PZT-5. Figure 6 , Figure 6The following is a schematic diagram for comparing the performance of different piezoelectric materials. The piezoelectric bodies 101 of the four materials are prepared into the same size and shape, and four groups of single-side clamped cantilever beam energy harvesters are prepared. At the same time, the energy harvesters of the four groups of different piezoelectric bodies 101 are tested in the free state and the clamped state. The test results are shown in the figure below. Figure 7-Figure 14 As shown, Frequency is frequency, Impedance is impedance, and Phase ang is phase angle. It can be seen that in the free state, the resonant frequencies of the single-sided clamped cantilever beam energy harvester prepared by

[011] polarized PIN-PMN-PT single crystal,

[001] polarized PIN-PMN-PT single crystal, PMNT textured ceramic and commercial ceramic PZT-5 are 14.7 kHz, 14.8 kHz, 17.1 kHz and 17.1 kHz, respectively. In contrast, in the clamped state, the resonant frequency of the energy harvester will drop significantly, and its resonant frequency is around 1.6 kHz. In addition, the impedance characteristics displayed by the energy harvester before and after work were tested. It was found that the impedance spectrum of the energy harvester hardly changed before and after the test, indicating that its structure is reasonable and has high stability.

[0097] At the same time, four groups of double-sided clamped cantilever beam energy harvesters were prepared, and only the materials of the piezoelectric body 101 were different. Figure 17-Figure 24 As shown in the figure, the impedance characteristics of the energy harvester were tested in the free state and the clamped state. In the free state, the resonant frequency of the double-sided clamped cantilever beam energy harvester is about 11.4 kHz. Compared with the free state of the single-sided clamped cantilever beam energy harvester, the resonant frequency of the device is slightly lower. This is because in the free state, the length of the substrate brass sheet of the double-sided clamped cantilever beam energy harvester is longer than that of the single-sided clamped cantilever beam energy harvester, which makes its resonant frequency slightly lower than that of the single-sided clamped cantilever beam energy harvester. The clamped state refers to the energy harvester being mounted on a vibration table through a fixed brass frame according to fixed constraints for testing. Both ends of the double-sided clamped cantilever beam energy harvester are fixed on the vibration table. That is, in the clamped state, the resonant frequency of the double-sided clamped cantilever beam energy harvester is about 4.6 kHz. Although it is significantly lower than the resonant frequency in the free state and unconstrained state, it is nearly 3 times higher than the resonant frequency (1.6 kHz) of the single-sided clamped cantilever beam energy harvester in the clamped state. This shows that changing the clamping constraints can effectively broaden the operating frequency band of the energy harvester.

[0098] Test Example 2

[0099] This test example provides a test of the relationship between the output voltage, frequency and acceleration of energy harvesters made of different piezoelectric body 101 materials. The single-side clamped cantilever beam energy harvester is fixed on a vibration table, and the output performance of energy harvesters made of different piezoelectric body 101 materials is tested by a vibration test analysis system. The test results include the test of the output voltage under 1 g acceleration and different excitation frequencies, and the test of the output voltage under 200 Hz excitation and different accelerations, such as Figure 15-16 As shown, Output voltage is the output voltage and Acceleration is the acceleration. Under the test frequency range of 1 Hz ~ 5 kHz and 1 g acceleration vibration, the

[011] polarized PIN-PMN-PT single crystal,

[001] polarized PIN-PMN-PT single crystal, PMNT textured ceramic and commercial ceramic PZT-5 energy harvester reached their respective maximum output voltage peaks at 1.45 kHz, and their output voltages reached 68 V, 25 V, 12 V and 8 V respectively. At the same time, Figure 15-16 We can find that at a frequency far below the resonant frequency, the output voltage of the energy harvester hardly changes with the operating frequency. In the acceleration range of 0.1 g to 1.4 g and at a test frequency of 200 Hz, the output voltage of the energy harvester is basically linearly correlated with the external excitation acceleration.

[0100] The same test was then performed on the double-sided clamped cantilever beam energy harvester. Figure 25-26 The output voltage test of the energy harvester under different frequency vibrations with an external excitation of 1 g acceleration and the output voltage test of the energy harvester under different acceleration vibrations with an external excitation of 1 kHz are shown. The test results show that within the test frequency range of 1 Hz to 5 kHz and under 1 g vibration acceleration, the magnitude of the output voltage is in the order of

[011] polarized PIN-PMN-PT single crystal,

[001] polarized PIN-PMN-PT single crystal, PMNT textured ceramic and commercial ceramic PZT-5 accelerometer, which is consistent with the piezoelectric constants d31 and g31 (or d32 and g32) of the corresponding piezoelectric materials. Under the acceleration range of 0.1 g to 1.3 g and the excitation test frequency of 1 kHz, the output voltage of the energy harvester is significantly linearly correlated with the magnitude of the excitation acceleration. It can be seen that the output voltage of the energy harvester using the

[011] polarized PIN-PMN-PT single crystal as the material of the piezoelectric body 101 is higher.

[0101] It should be noted that the PMNT textured ceramics are specifically lead magnesium niobate-lead titanate textured ceramics.

[0102] In summary, according to Figure 7-Figure 26 As shown, the resonant frequencies of the four piezoelectric materials are all around 1.6 kHz. Taking the output voltage as the criterion, the preferred order of materials for the piezoelectric body 101 is

[011] -polarized PIN-PMN-PT single crystal,

[001] -polarized PIN-PMN-PT single crystal, PMNT textured ceramics, and commercial ceramic PZT-5.

[0103] The present invention uses high-performance piezoelectric materials, which further improves the output performance of the energy collector compared to other common materials of the piezoelectric body 101. The double-sided clamped cantilever beam energy collector based on the piezoelectric single crystal proposed in the present invention has the advantages of simple structure, high output voltage, and wide operating frequency band compared to the single-sided clamped energy collector and the energy collector prepared by traditional piezoelectric materials. It provides new research ideas and solutions to solve the problems of narrow operating frequency band, low output voltage and poor stability of energy collectors.

[0104] See also Figure 1 and Figure 2 , the present invention provides a double-sided clamped cantilever beam energy collector, the fixed base 104 is an H-shaped fixed base;

[0105] The fixed base 104 includes a first vertical member, a second vertical member and a horizontal member;

[0106] The first vertical piece is fixedly connected to the second vertical piece through the horizontal piece.

[0107] It should be noted that the fixed base 104 is made of brass. The fixed base 104 refers to the base for fixing and clamping the cantilever beam 102, and has bolt 103 holes processed at both ends, which correspond to the bolt 103 holes of the cantilever beam 102 one by one. That is, bolt 103 holes are processed at the top of the first vertical member and the second vertical member, which correspond to the bolt 103 holes of the cantilever beam 102 one by one. In the present invention, the first vertical member and the second vertical member are preferably rectangular structures, and the horizontal member is a horizontal bar, and the two ends of the horizontal bar are fixedly connected to the opposite surfaces of the first vertical member and the second vertical member respectively.

[0108] It is worth mentioning that the fixed base 104 of the H-shaped structure provides a more stable support for the cantilever beam 102 in the plane. When the two ends of the cantilever beam 102 are fixed to the upper end of the H-shaped base, compared with other simple fixed structures, the H-shaped base can better resist the torsion and lateral displacement of the cantilever beam 102 in the plane. At the same time, in space, the H-shaped structure helps to prevent the cantilever beam 102 from shaking in the direction perpendicular to its vibration plane. Since the middle free part does not contact the cantilever beam 102, when the cantilever beam 102 undergoes bending vibration, the structure of the H-shaped base can limit the excessive displacement of the cantilever beam 102 in the vertical direction, ensuring that the vibration of the cantilever beam 102 is mainly concentrated in the expected bending direction, thereby improving the efficiency of energy conversion.

[0109] It is worth mentioning that micro cylindrical protrusions are arranged on the upper end of the fixed base 104, and these protrusions can be evenly distributed in the fixed area of ​​the cantilever beam 102, which can increase the contact area between the cantilever beam 102 and the base, and ensure that the cantilever beam 102 can be evenly stressed during vibration, thereby improving the stress transfer efficiency. At the same time, by increasing the roughness of the contact surface between the fixed base 104 and the cantilever beam 102, the friction between the two can be increased, thereby enhancing the fixing effect.

[0110] See also Figure 1 and Figure 2 , the present invention provides a double-sided clamped cantilever beam type energy collector, and threaded holes are provided at both ends of the cantilever beam 102;

[0111] One end of the cantilever beam 102 is threadedly connected to the top of the first vertical member through a bolt 103;

[0112] The other end of the cantilever beam 102 is threadedly connected to the top of the second vertical member through a bolt 103 .

[0113] It should be noted that the cantilever beam 102 is fixed to the fixed base 104 by bolts 103 to prevent displacement of both ends of the cantilever beam 102 when the cantilever beam 102 vibrates.

[0114] In summary, the double-sided clamped cantilever beam energy collector provided by the present invention has a simple structure, is easy to prepare, and does not require a starting power supply. Therefore, it can reduce the complexity of the energy collector assembly and has high reliability, so that it can be applied to various precision equipment to extend its service life.

[0115] See also Fig. 27 The present invention provides a method for using a double-sided clamped cantilever beam energy collector, comprising:

[0116] Step 101 , fixing both ends of a cantilever beam 102 on a fixed base 104 , and installing a piezoelectric body 101 on both the upper end surface and the lower end surface of the cantilever beam 102 .

[0117] Step 102 : When the cantilever beam 102 is subjected to external excitation and generates bending vibration, the piezoelectric body 101 on the upper end surface and the piezoelectric body 101 on the lower end surface are deformed simultaneously, generating electric energy and conducting it out.

[0118] In an embodiment of the present invention, both ends of the cantilever beam 102 are fixed on a fixed base 104, and a piezoelectric body 101 is installed on the upper end face and the lower end face of the cantilever beam 102; when the cantilever beam 102 is subjected to external excitation to generate bending vibration, the piezoelectric body 101 on the upper end face and the piezoelectric body 101 on the lower end face are deformed at the same time, generating electric energy and conducting it out; the present invention installs a piezoelectric body 101 on the upper end face and the lower end face of the cantilever beam 102 to form a double-chip multi-layer structure of a piezoelectric layer-substrate layer-piezoelectric layer, and then adopts a bilateral clamping and fixing structure. When there is mechanical vibration in the external environment, the bilaterally clamped cantilever beam energy collector senses the vibration and causes the inertial force to act on the piezoelectric body 101, thereby causing it to bend and deform, and based on the positive piezoelectric effect, a charge signal that is proportional to the input acceleration is generated on the surface of the piezoelectric body 101, further broadening the working frequency band of the energy collector.

[0119] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0120] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0121] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A double-sided clamped cantilever beam energy harvester, characterized in that: including cantilever beams; Both ends of the cantilever beam are fixedly connected to a fixed base; The upper end surface and the lower end surface of the cantilever beam are both installed with a piezoelectric body, and the piezoelectric body is used to generate electric energy by deforming through the bending vibration of the cantilever beam, and is used to extract the electric energy.

2. The double-sided clamped cantilever beam energy collector according to claim 1, characterized in that: The polarization directions of the piezoelectric bodies mounted on the two end surfaces of the cantilever beam are opposite.

3. The double-sided clamped cantilever beam energy collector according to claim 1, characterized in that: The piezoelectric bodies installed on the two end surfaces of the cantilever beam are made of the same piezoelectric body material.

4. The double-sided clamped cantilever beam energy collector according to claim 3, characterized in that: A ground electrode layer is provided on one side of the piezoelectric body close to the cantilever beam; A positive output electrode layer is arranged on a side of the piezoelectric body away from the cantilever beam.

5. The double-sided clamped cantilever beam energy collector according to claim 1, characterized in that: The piezoelectric body is a long strip-shaped piezoelectric body.

6. The double-sided clamped cantilever beam energy collector according to claim 1, characterized in that: The piezoelectric body is bonded and fixed to the cantilever beam through epoxy resin.

7. The double-sided clamped cantilever beam energy collector according to any one of claims 1 to 6, characterized in that: The material of the piezoelectric body is any one of indium-doped lead magnesium niobate-lead titanate single crystal, PMNT textured ceramics and lead zirconate titanate ceramics.

8. The double-sided clamped cantilever beam energy collector according to claim 1, characterized in that: The fixed base is an H-shaped fixed base; The fixed base includes a first vertical member, a second vertical member and a horizontal member; The first vertical member is fixedly connected to the second vertical member through the horizontal member.

9. The double-sided clamped cantilever beam energy collector according to claim 8, characterized in that: Threaded holes are provided at both ends of the cantilever beam; One end of the cantilever beam is threadedly connected to the top of the first vertical member through a bolt; The other end of the cantilever beam is threadedly connected to the top of the second vertical member through a bolt.

10. A method for using the double-sided clamped cantilever beam energy collector according to any one of claims 1 to 9, characterized in that: include: The two ends of the cantilever beam are fixed on a fixed base, and a piezoelectric body is installed on the upper end surface and the lower end surface of the cantilever beam; When the cantilever beam is subjected to external excitation and generates bending vibration, the piezoelectric body on the upper end surface and the piezoelectric body on the lower end surface are deformed simultaneously, generating electric energy and conducting it out.

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