Composite vibration energy collecting device based on liquid metal

Abstract

The invention belongs to the technical field of energy collection, and particularly relates to a composite vibration energy collection device based on liquid metal, which comprises a fixed part, a cantilever beam and a piezoelectric part, one end of the cantilever beam is fixedly connected with the fixed part, and the piezoelectric part is fixed at one end, close to the fixed part, of the cantilever beam; the device further comprises liquid metal, a friction layer and a friction working electrode, a groove is formed in the upper surface of the cantilever beam, the liquid metal is arranged in the groove, the friction layer is arranged on the upper surface of the liquid metal, and the friction working electrode is inserted into the liquid metal. Nonlinear disturbance is introduced through free shaking of liquid metal, response to multi-frequency vibration signals is achieved, and the frequency response bandwidth of a cantilever beam system is widened. Besides, the interaction between the liquid metal and the friction layer in the shaking process and the contact friction between the liquid metal and the inserted electrode achieve collection of composite energy such as triboelectrification and charge disturbance, and mechanical kinetic energy and friction energy of the liquid metal are fully utilized.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy harvesting, and particularly relates to a composite vibration energy harvesting device based on liquid metal. Background Art

[0002] Cantilever beam vibration energy harvesting devices are widely used in micro-energy acquisition, structural health monitoring, intelligent sensing and other fields due to their simple structure, small size and high sensitivity. Traditional cantilever beam energy harvesting systems mostly use piezoelectric materials to convert the strain of the beam during vibration into electrical energy. However, due to the inherent resonance frequency of the cantilever beam system, its energy harvesting efficiency is relatively high near this frequency, but its response ability to a broadband vibration environment is limited, the frequency response range is narrow, and it cannot effectively adapt to multi-source and variable vibration conditions.

[0003] In recent years, researchers have tried to broaden the frequency response bandwidth of the cantilever beam by introducing nonlinear structures, additional mass blocks, magnetic coupling, etc. However, these methods often lead to the complication of the device structure, many regulation parameters, increased manufacturing difficulty and cost. In addition, in some vibration environments with high-frequency or micro-perturbation characteristics, such as fluid excitation in pipelines and micro-perturbations during equipment operation, the traditional structure is still insufficient in terms of energy capture (Small 2024, 20, 2400698., NanoEnergy, 74, 2020, 104770.). Summary of the Invention

[0004] To solve the above problems, the present invention provides a composite vibration energy harvesting device based on liquid metal, which includes a fixing part, a cantilever beam, and a piezoelectric part. One end of the cantilever beam is fixedly connected to the fixing part, and the piezoelectric part is fixed at one end of the cantilever beam close to the fixing part; in addition, the present invention also includes liquid metal, a friction layer, and a friction working electrode. A groove is provided on the upper surface of the cantilever beam, the liquid metal is arranged in the groove, the friction layer is placed on the upper surface of the liquid metal, and the friction working electrode is inserted into the liquid metal.

[0005] The composite vibration energy harvesting device based on liquid metal of the present invention drives the liquid metal arranged in the groove on its upper surface to shake along with the periodic bending vibration of the cantilever beam under the external vibration excitation. During the shaking process of the liquid metal, friction occurs with the friction layer above, generating the phenomenon of triboelectrification. At the same time, the friction working electrode is inserted into the liquid metal, and it can sense the charge perturbation and potential change of the liquid metal during the movement process, thereby outputting the corresponding electrical signal. Meanwhile, the piezoelectric part located at the root of the cantilever beam generates a strain electric effect due to the periodic deformation of the beam body, further converting mechanical vibration energy into electrical energy. The shaking of the liquid metal not only introduces non-linear dynamic perturbations, significantly broadening the frequency response range of the cantilever beam system, but also forms an auxiliary energy harvesting path through friction and contact electrification effects, realizing the multi-source composite conversion and efficient collection of mechanical energy.

[0006] Furthermore, the liquid metal is close to the free end of the cantilever beam. Arranging the liquid metal in the free end area of the cantilever beam can enable it to obtain a larger displacement amplitude and inertial shaking force during vibration, thereby significantly enhancing the relative motion effect between it and the friction layer. Since the vibration amplitude of the free end of the cantilever beam is the largest, this layout is conducive to the liquid metal generating more significant non-linear perturbations, improving the energy harvesting efficiency, and effectively expanding the frequency response range of the device.

[0007] Furthermore, the liquid metal does not fill the groove completely. The incomplete filling of the liquid metal in the groove can form a free movement space in the cavity, allowing it to generate complex shaking modes at different frequencies, such as impact, slip, and collision. This non-full filling state introduces non-linear dynamic behaviors, breaking the single frequency limit of the traditional resonant system, so that the energy harvesting system can adapt to a wider frequency range and improve the response ability to low-frequency and multi-frequency vibration sources.

[0008] Furthermore, the friction working electrode is a copper electrode. Using copper as the material of the friction working electrode has excellent electrical conductivity and mechanical stability, which is beneficial to efficiently capturing the electrical signal generated by the shaking of the liquid metal. The copper material also has good wear resistance and corrosion resistance, suitable for long-term contact work with the liquid metal, improving the stability and service life of the device.

[0009] Furthermore, the liquid metal is a gallium-based alloy, an indium-based alloy, or a tin-based alloy. Selecting gallium-based, indium-based, or tin-based liquid metal as the working medium has good electrical conductivity, fluidity, and chemical stability, can remain in a liquid state at room temperature, and meets the requirements of long-term operation. These liquid metal alloys have a low evaporation rate and a strong self-healing ability of the oxide film, which is beneficial to maintaining the friction performance and electrical signal stability.

[0010] Furthermore, the friction layer is a flexible polymer material. As the friction layer, the flexible polymer material can provide an appropriate friction coefficient during contact with the liquid metal, and at the same time has a certain buffering and deformation ability to reduce the energy loss during the impact of the liquid metal. This structure can also adapt to thermal expansion and contraction in different environments, effectively improving the mechanical adaptability and durability of the device.

[0011] Furthermore, the friction layer is the oxide layer on the surface of the liquid metal. Using the naturally formed oxide layer on the surface of the liquid metal as the friction layer not only simplifies the device structure and avoids introducing additional materials. At the same time, the dielectric constant of the liquid metal oxide layer is relatively high, so its surface has a relatively high charge density. It can also effectively enhance the charge separation effect during the friction contact process. The oxide layer shell has a certain elastic strain and recovery ability, and can release instantaneous charges during the mechanical contact / fracture process, improving the strength and frequency response sensitivity of the triboelectric signal.

[0012] Furthermore, the friction working electrode is arranged along the direction of the cantilever beam, and at the end of the friction working electrode in the liquid metal, it is upturned. Arranging the friction working electrode along the direction of the cantilever beam helps to improve its ability to synchronously respond with the vibration of the beam body in the liquid metal. The design of the upturned electrode end can form periodic contact and separation during the sloshing of the liquid metal, enhancing the electrical signal modulation ability, and at the same time avoiding dead-end contact between the electrode and the bottom of the groove, improving the dynamic stability of the structure.

[0013] Furthermore, the end of the friction working electrode is L-shaped. The L-shaped electrode end can form a local flow disturbance area during the sloshing of the liquid metal, increasing the friction interface area between the electrode and the liquid metal, thereby enhancing the triboelectrification efficiency. This structure can also effectively position or limit the position of the electrode, preventing it from shifting or becoming unstable during vibration, enhancing the reliability of the device.

[0014] Furthermore, a partial area of the groove is arc-shaped, and the liquid metal is placed in the arc-shaped area. The arc-shaped groove structure can provide flexible boundary constraints during the sloshing of the liquid metal, causing it to have a periodic rebound and dynamic focusing effect, enhancing the nonlinear dynamic response. At the same time, the arc-shaped area helps the liquid metal to form more complex flow trajectories in the cavity, increasing the diversity of the energy coupling path and the output intensity of the friction signal.

[0015] Advantages of the present invention: (1) By introducing non-linear disturbances through the free sloshing of the liquid metal, the present invention realizes the response to multi-frequency vibration signals, broadening the frequency response bandwidth of the cantilever beam system.

[0016] (2) During the shaking process, the interaction between the liquid metal and the friction layer, as well as the contact friction with the inserted electrode, realize the composite energy harvesting such as triboelectrification and charge perturbation, and make full use of the mechanical kinetic energy and frictional energy of the liquid metal.

[0017] (3) In the present invention, by integrating a liquid metal unit on the cantilever beam, the energy enhancement function can be realized without additional complex mechanical structures, and the structure is compact, the processing is simple, and the reliability is high.

[0018] Combining the above beneficial effects, the present invention has good application prospects in the field of energy harvesting technology. Description of the Drawings

[0019] Figure 1 It is a schematic diagram of a composite vibration energy harvesting device based on liquid metal.

[0020] Figure 2 It is a schematic diagram of the cantilever beam, liquid metal, and friction layer.

[0021] Figure 3 It is a short-circuit current signal diagram under mechanical vibration and ultrasonic excitation Figure 4 It is an open-circuit voltage signal diagram under mechanical vibration excitation Figure 5 It is a schematic diagram of the friction working electrode with a suspended end.

[0022] Figure 6 It is a schematic diagram of the arc-shaped groove and the liquid metal.

[0023] In the figure: 1, fixed part; 2, cantilever beam; 3, piezoelectric part; 4, groove; 5, liquid metal; 6, friction layer; 7, friction working electrode. Detailed Embodiments

[0024] To make the objectives, technical solutions and advantages of the present application more clear and understandable, the following examples are given with reference to the accompanying drawings to further elaborate on the present application in detail.

[0025] Embodiment 1 This embodiment provides a composite vibration energy harvesting device based on liquid metal, as Figure 1 and Figure 2As shown in the figure, it includes a fixed part 1, a cantilever beam 2, and a piezoelectric part 3. The fixed part 1 is made of stainless steel or aluminum alloy, with good mechanical strength and corrosion resistance. The fixed part 1 provides the installation and structural support for the overall device. One end of the cantilever beam 2 is fixedly connected to the fixed part 1, forming a "fixed-free" boundary condition, which helps to form a typical vibration mode of the cantilever beam 2. The cantilever beam 2 is made of titanium alloy or stainless steel, and the cantilever beam 2 has a high elastic modulus and corrosion resistance to liquid metal 5. The length of the cantilever beam is 40 mm to 80 mm, the width is 10 mm to 20 mm, and the thickness is 0.3 mm to 1 mm. Under external excitation, the cantilever beam 2 generates bending vibration, drives the liquid metal 5 to slosh, and at the same time provides a stress source for the piezoelectric part 3 to achieve the conversion of mechanical energy. Specifically, the piezoelectric part 3 is fixed at a position near the fixed end of the cantilever beam 2 and is used to convert the strain energy generated by the vibration of the cantilever beam 2 into electrical energy. The piezoelectric part 3 is made of PZT ceramic or PVDF piezoelectric film. The length of the piezoelectric part 3 is 10 mm to 20 mm, the width is 5 mm to 10 mm, and the thickness is 0.2 mm to 0.5 mm. A groove 4 is provided on the upper surface of the cantilever beam 2. The length of the groove 4 is about 10 mm to 20 mm, the width is 5 mm to 10 mm, and the depth is 1 mm to 3 mm. The groove 4 is arranged near the free end of the cantilever beam 2. The groove 4 is used to accommodate the liquid metal 5 so that it generates a sloshing behavior under excitation. Specifically, the groove 4 is filled with the liquid metal 5. The liquid metal 5 is preferably a gallium-based alloy, an indium-based alloy, or a tin-based alloy, which is in a liquid state at room temperature. The volume of the liquid metal 5 does not fill the groove completely, and the filling ratio is 30% to 70% to allow it to slosh during vibration. A friction layer 6 is arranged above the liquid metal 5. The friction layer 6 can be a flexible polymer material such as PDMS or PTFE, which is used to generate a triboelectric effect when contacting the liquid metal 5. The friction working electrode 7 is inserted into the liquid metal 5, and the friction working electrode 7 is made of copper material.

[0026] Preferably, the friction layer 6 adopts a rough surface design to enhance the contact effect between the liquid metal 5 and the friction layer 6. The rough surface provides more microscopic contact sites, thereby increasing the effective contact area and significantly improving the friction force. The contact friction between the liquid metal 5 and the rough friction layer 6 during vibration can not only effectively promote the triboelectric effect and charge separation, but also enhance the energy harvesting efficiency. In addition, the rough surface helps to form more local friction regions when the liquid metal 5 sloshes, further improving the conversion effect of friction energy.

[0027] Preferably, the end of the friction working electrode 7 is designed to be flat and upturned. The flat and upturned design can increase the contact area between the friction working electrode 7 and the liquid metal 5, enhance the triboelectric effect, and make the charge separation and accumulation more efficient. In addition, the upturned structure can keep the friction working electrode 7 in a relatively stable contact state during the shaking of the liquid metal 5, avoiding the contact breakage or instability between the friction working electrode 7 and the liquid metal 5, and thus improving the signal stability and the continuity of the electric energy output.

[0028] During operation, an external excitation (such as mechanical vibration, air flow impact, sound wave) causes the cantilever beam 2 to vibrate periodically. The liquid metal 5 in the groove 4 shakes under the action of inertia, generates triboelectricity when contacting the friction layer 6, and at the same time, the friction working electrode 7 senses the charge perturbation in the liquid metal and outputs a signal. The piezoelectric part synchronously responds to the strain change of the beam and outputs electric energy, and the whole device forms a "piezoelectric + friction + flow induction" composite energy harvesting path.

[0029] In this embodiment, the other end of the friction working electrode 7 is connected to a load, and the other end of the load is grounded, forming a single-electrode working mode. When the liquid metal 5 rubs against the friction layer 6 during vibration, the friction working electrode 7 senses the charge change generated by the liquid metal 5 and transmits it to the load through the friction working electrode 7. The other end of the load is grounded to form a closed circuit, enabling the current to flow through the load, thereby realizing the effective collection and utilization of energy. This single-electrode working mode simplifies the circuit design, reduces the system complexity, and improves the reliability and convenience of use of the energy harvesting device.

[0030] As Figure 3 a is the current output signal of the generator under the conditions of mechanical vibration and ultrasonic excitation. From the current signal, it can be seen that at this time, the generator generates a maximum peak current exceeding 40 μA under mechanical vibration, showing an obvious AC pulse signal with a frequency of about 3 Hz; As Figure 3 b is the signal after local current amplification. It can be seen that the generator generates relatively dense current signals when subjected to ultrasonic excitation, and the peak current exceeds 2 μA. From the current output, it can be seen the composite output ability of the present invention under various modes (mechanical vibration energy and ultrasonic excitation) conditions.

[0031] In addition, Figure 4 a is the voltage output signal under the condition of mechanical vibration for a period of time, Figure 4 b is the local amplified voltage signal in the initial stage, Figure 4c is the locally amplified voltage signal after a period of time. It can be seen that the peak voltage in the initial stage exceeds 100V. As the number of mechanical vibration impacts increases, the single-peak voltage also gradually increases, and the voltage curve shows an accumulative growth trend. This is because the continuous contact of the liquid metal friction interface causes the enhancement of the friction electric field, which in turn causes the increase of the charge density, and finally the voltage curve gradually saturates.

[0032] In addition, the electric energy generated by the piezoelectric part 3 and the electric energy generated by the friction working electrode 7 are integrated through a circuit and applied together. Specifically, the alternating current signal generated by the piezoelectric part 3 through strain first passes through a rectifying circuit (such as a diode bridge rectifier) to convert the alternating current into direct current. At the same time, the electric energy generated by the friction working electrode 7 through friction with the liquid metal 5 is also guided to the circuit, passed through an amplifying circuit (such as an operational amplifier) to enhance the signal strength, and then merged with the electric energy of the piezoelectric part 3. The combined electric energy of the two is adjusted by a voltage regulating circuit (such as a voltage regulator) to adapt to the load demand. Finally, the regulated direct current electric energy is stored through an energy storage device such as a battery or a supercapacitor, or directly drives an external load.

[0033] Preferably, a layer of silicon dioxide layer is provided at the bottom of the groove 4 as an insulating film. The silicon dioxide layer has excellent insulating properties, effectively preventing the direct contact between the liquid metal and the bottom of the cantilever beam, thus avoiding electrical short circuits or unnecessary interference in the conduction path. In addition, the silicon dioxide layer also provides good chemical stability, preventing chemical reactions or corrosion between the liquid metal and the cantilever beam material, and extending the service life of the device. The smooth surface characteristics of silicon dioxide can also reduce the direct friction between the liquid metal 5 and the bottom of the groove 4, making it more flexible and efficient during vibration, thereby improving the energy harvesting efficiency.

[0034] Preferably, the side of the groove 4 close to the free end of the cantilever beam 2 is designed to be deeper, which has significant advantages. First of all, the free end of the cantilever beam 2 has a larger displacement amplitude during vibration, and the liquid metal 5 will be more likely to accumulate and slosh in the deeper groove 4 area, thus enhancing the relative movement between the liquid metal 5 and the friction layer 6 and increasing the intensity of the triboelectrification effect. This design can effectively utilize the larger amplitude of the free end, promote the free flow and collision of the liquid metal 5 in the groove 4, and increase the efficiency of electric energy collection. At the same time, the deeper groove 4 area helps to guide the liquid metal 5 to move towards the deeper side, preventing it from overflowing the groove 4 during vibration, thus ensuring the stability and reliability of the device. Through this design, more efficient energy conversion and stable electric energy output can be achieved. Especially in high-frequency vibration or complex vibration environments, it helps to broaden the frequency response range of the device and improve the overall performance.

[0035] Example 2 Based on Example 1, the friction layer 6 is an oxide layer on the surface of the liquid metal 5. The friction layer 6 being an oxide layer on the surface of the liquid metal 5 replaces the flexible polymer material. The liquid metal 5 (such as a gallium-based alloy) will naturally form a thin oxide layer on its surface when exposed to air. This oxide layer has good friction characteristics and can generate a triboelectric effect with the liquid metal 5. In this design, the oxide layer on the surface of the liquid metal 5 not only simplifies the structure and avoids the use of additional materials, but also can produce an efficient charge separation effect during friction, improving the efficiency of electric energy harvesting. In addition, the oxide layer has high chemical stability, which can prevent the liquid metal from undergoing a corrosion reaction with other materials, thereby extending the service life of the device. Through this design, the function of the friction layer 6 is closely combined with the body of the liquid metal 5, further enhancing the overall performance and stability of the device.

[0036] Example 3 Based on Example 1 or 2, as Figure 5 shown, the friction working electrode 7 is arranged along the direction of the cantilever beam 2 and inserted into the liquid metal 5. Inside the liquid metal 5, the end of the friction working electrode 7 is upturned. The end of the friction working electrode 7 is designed with an L-shaped upturned structure. This design enhances the contact area and contact frequency between the liquid metal 5 and the friction working electrode 7 during vibration, thereby improving the generation efficiency of the triboelectric effect. Specifically, during the sloshing of the liquid metal 5, the L-shaped end of the friction working electrode 7 can form a more stable and repeated contact between the liquid metal 5 and the friction working electrode 7, thereby strengthening the accumulation and transmission of charges and effectively increasing the electric energy output. The friction working electrode 7 is arranged along the direction of the cantilever beam 2, which can ensure that it participates in the triboelectric process throughout the entire movement range of the liquid metal 5, thus maximizing the energy collection effect. In addition, the L-shaped upturned structure not only improves the stability of the friction working electrode 7 and prevents it from shifting during vibration, but also optimizes the movement of the liquid metal 5 in the groove, reducing unnecessary friction losses. This design simplifies the structure of the electrode, while enhancing the energy collection efficiency and improving the overall performance of the device.

[0037] Example 4 Based on Examples 1 - 3, as Figure 6As shown, a partial area of the groove 4 is arc-shaped, and the liquid metal 5 is placed within the arc-shaped area. This design enhances the dynamic response and non-linear behavior of the liquid metal 5 through the geometric shape of the arc-shaped groove 4 area. When the cantilever beam 2 is subjected to an external vibration excitation, the liquid metal 5 sloshes within the arc-shaped area. The arc-shaped structure helps the liquid metal 5 move more orderly during vibration and generates a more significant rebound effect, thereby increasing the relative movement amplitude of the liquid metal 5. The design of the arc-shaped area introduces an additional elastic restoring force, effectively enhancing the dynamic perturbation of the liquid metal 5 and strengthening the intensity of the triboelectric effect. This design can also enable the liquid metal 5 to form more complex flow trajectories within the groove 4, further optimizing the energy harvesting efficiency. In addition, the arc-shaped groove 4 helps control the movement range of the liquid metal 5, avoiding energy waste caused by excessive sloshing. Meanwhile, the geometric shape of the arc-shaped area can cause the liquid metal 5 to generate more frequent triboelectric phenomena during contact with the friction layer 6 and the friction working electrode 7, further enhancing the effect of electrical energy collection. The arc-shaped design not only optimizes the movement mode of the liquid metal 5 but also improves the response ability of the entire energy harvesting system to broadband vibration sources, thereby broadening the frequency response range of the device and enhancing the energy harvesting efficiency and the reliability of the device.

[0038] Example 5 This embodiment provides an application of the present invention in structural health monitoring. Traditional structural health monitoring systems rely on external power sources or batteries for power supply, suffering from problems such as short maintenance cycles and unstable energy supply. However, the composite vibration energy harvesting device based on liquid metal provided by the present invention can collect the weak vibration energy generated by the structure itself (such as wind power, traffic vibration, or structural self-vibration, etc.) to provide continuous power supply for the sensor, thereby realizing a self-powered monitoring system. Such a device can be embedded or fixed at key parts of the structure (such as the support points of bridges, the beam-column joints of buildings, or the monitoring nodes in tunnels), and utilize the vibrations generated at these parts to drive the device to work. Specifically, when the structure vibrates, the cantilever beam 2 in the device bends, driving the liquid metal 5 to slosh within the groove 4. Meanwhile, the friction layer 6 and the friction working electrode 7 collect electrical energy through the triboelectric effect, and the piezoelectric part 3 generates electrical energy in response to the vibration strain. These electrical energies are rectified and regulated and then provided to the monitoring sensor, battery, or wireless communication module, enabling the entire monitoring system to operate continuously without an external power source. Through this energy harvesting method, the present invention not only improves the autonomy and reliability of the monitoring system but also reduces the battery replacement and maintenance costs in traditional systems, being particularly suitable for engineering projects in remote areas or areas where it is difficult to access the power grid, ensuring the long-term and stable operation of structural health monitoring.

[0039] Example 6 This embodiment provides an application of the present invention in an intelligent transportation system. In an intelligent transportation system, devices such as road sensors, traffic lights, and surveillance cameras need to operate continuously. Traditional power supply solutions often rely on batteries or external power sources, which have problems such as inconvenient maintenance and unstable energy supply. Through the composite vibration energy harvesting device based on liquid metal of the present invention, the vibration energy generated in the road surface or transportation facilities (such as the vibration during vehicle driving, wind force, or pedestrian flow, etc.) can be utilized to provide continuous power for these devices. Specifically, the cantilever beam 2 in the device bends under traffic vibration or other external excitations, the liquid metal 5 sloshes in the groove 4, and electricity is generated through the friction between the friction layer 6 and the friction working electrode 7. At the same time, the piezoelectric part 3 converts vibration strain into electricity. Through a rectifying and regulating circuit, the harvested electrical energy can provide continuous power for traffic lights, sensors, and other wireless communication devices, thus realizing the seamless operation of the devices. Especially in remote areas or regions with relatively old road infrastructure, the present invention can significantly reduce the dependence on traditional energy supply, provide a green and reliable energy harvesting method, support the automated management and monitoring of the intelligent transportation system, and improve traffic management efficiency and safety. At the same time, this self-powered system reduces the frequency of battery replacement and maintenance, reduces operating costs, and enhances the sustainability and long-term effectiveness of the system.

[0040] In summary, the present invention provides a composite vibration energy harvesting device based on liquid metal, which realizes the efficient harvesting of multi-source vibration energy by combining the piezoelectric effect, triboelectric effect, and flow induction of liquid metal. The device includes a fixing part 1, a cantilever beam 2, a piezoelectric part 3, a liquid metal 5, a friction layer 6, and a friction working electrode 7. Among them, the cantilever beam 2 drives the sloshing of the liquid metal 5 through vibration, the friction between the liquid metal 5 and the friction layer 6 generates charges, and the friction working electrode 7 senses the charge change and outputs an electrical signal. At the same time, the piezoelectric part responds to vibration strain to generate electrical energy. If integrated through a circuit, the electrical energy generated by the piezoelectric part 3 and the friction working electrode 7 can be combined and jointly applied to further improve the energy harvesting efficiency. In summary, the present invention provides a device with a simple structure, diverse functions, and high-efficiency energy harvesting, which is applicable to fields such as micro-energy harvesting, intelligent sensing, and wearable devices.

[0041] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the scope of protection of the present application.

Claims

1. A composite vibration energy harvesting device based on liquid metal, comprising a fixed part, a cantilever beam, and a piezoelectric part, wherein one end of the cantilever beam is fixedly connected to the fixed part, and the piezoelectric part is fixed on one end of the cantilever beam close to the fixed part, characterized in that: It also includes liquid metal, a friction layer, and a friction working electrode. The upper surface of the cantilever beam is provided with a groove, the liquid metal is arranged in the groove, the friction layer is placed on the upper surface of the liquid metal, and the friction working electrode is inserted into the liquid metal.

2. The liquid metal-based composite vibration energy harvesting device according to claim 1, characterized in that: The liquid metal is close to the free end of the cantilever beam.

3. The liquid metal-based composite vibration energy harvesting device according to claim 1, characterized in that: The liquid metal does not completely fill the groove.

4. The liquid metal-based composite vibration energy harvesting device according to claim 1, characterized in that: The friction working electrode is a copper electrode.

5. The liquid metal-based composite vibration energy harvesting device according to claim 1, characterized in that: The liquid metal is a gallium-based alloy, an indium-based alloy, or a tin-based alloy.

6. The liquid metal-based composite vibration energy harvesting device according to claim 1, characterized in that: The friction layer is made of flexible polymer material.

7. The liquid metal-based composite vibration energy harvesting device according to claim 1, characterized in that: The friction layer is an oxide layer on the surface of the liquid metal.

8. The liquid metal-based composite vibration energy harvesting device according to any one of claims 1 to 7, characterized in that: The friction working electrode is arranged along the direction of the cantilever beam, and the end of the friction working electrode is tilted in the liquid metal.

9. The liquid metal-based composite vibration energy harvesting device according to claim 8, characterized in that: The end of the friction working electrode is L-shaped.

10. The liquid metal-based composite vibration energy harvesting device according to claim 9, characterized in that: A partial area of ​​the groove is arc-shaped, and the liquid metal is placed in the arc-shaped area.

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