Micro-energy collection cluster system based on piezoelectric material and preparation method and application thereof

Abstract

The invention provides a piezoelectric material-based micro-energy collection cluster system and a preparation method and application thereof. The system is composed of a plurality of piezoelectric micro-energy collection units, and each unit is designed to be of a bionic structure such as leaves and petals. And packaging. Through a three-dimensional series-parallel topological network integration unit, modular hot plug deployment is supported, a rectifying circuit and a hybrid energy storage unit (a lithium battery and a super capacitor) are arranged, the AC / DC conversion efficiency is larger than or equal to 85%, and the charging and discharging efficiency is larger than or equal to 95%. The method can be applied to scenes such as intelligent landscape trees, building outer walls and vehicle-mounted equipment. The system has the characteristics of high energy density, broadband self-adaption and environment friendliness, a sustainable energy solution is provided for the fields of Internet of Things, smart cities and the like, and the problems of low output power, poor frequency adaptability, limited environment deployment and the like in the prior art can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of micro energy harvesting, and particularly to a piezoelectric material-based micro energy harvesting cluster system, its preparation method and applications. Background Art

[0002] The combustion of traditional energy sources, especially fossil fuels such as coal and oil, is the main source of greenhouse gas (especially carbon dioxide) emissions, bringing problems such as environmental pollution and resource waste. Accelerating the promotion of renewable energy substitution can address climate change and promote high-quality and sustainable economic development. At the same time, the popularization of low-power electronic devices such as the Internet of Things and wearable devices has put forward an urgent demand for sustainable and maintenance-free energy supply. Traditional batteries are difficult to meet the long-term power supply requirements due to defects such as limited capacity and the need for regular replacement or charging. In this context, micro energy harvesting technology has emerged. It captures weak energies such as light energy, heat energy, mechanical energy, and radio frequency energy from the environment and converts them into electrical energy, providing an innovative solution for device power supply and having significant application potential.

[0003] In micro energy harvesting technology, piezoelectric micro energy harvesting cluster systems have attracted much attention due to their advantages such as high energy conversion efficiency, simple structure, and no electromagnetic interference. Its core principle is to convert mechanical vibration energy in the environment into electrical energy through the direct piezoelectric effect of piezoelectric materials. However, the following key problems still exist in the existing technology:

[0004] (1) Low output power: The output power of a single piezoelectric unit is usually in the microwatt level, making it difficult to meet the actual application requirements.

[0005] (2) High frequency dependence: The existing systems have poor adaptability to vibration frequency and amplitude.

[0006] (3) Material and structure limitations: At present, rigid piezoelectric materials (such as PZT ceramics) are used, resulting in difficulty for the device to fit complex environments or flexible scenarios; and the single energy mode (only mechanical energy harvesting) limits the energy density.

[0007] CN117740081A provides a self-powered agricultural environment sensing system based on flexible nano-piezoelectric materials. By setting a flexible piezoelectric film, a power generation controller, an ultra-low power consumption sensing subsystem, and a high-impedance sensor, the power generation controller controls the micro energy harvester to start collecting alternating signals of multiple nano-piezoelectric components and controls the charge transfer capacitor to reach the pre-charged state. The ultra-low power consumption sensing subsystem drives the high-impedance sensor to detect environmental parameters, and the micro energy harvester drives the charge transfer capacitor and the main energy storage capacitor to cooperate to achieve voltage regulation and impedance transformation. However, the nano-piezoelectric components in CN117740081A are of ordinary sheet structure, without the extensive energy supply applications brought by bionic structures.

[0008] In view of the above problems, the present invention proposes a brand-new piezoelectric micro energy harvesting cluster system. Summary of the Invention

[0009] The object of the present invention is to solve the above problems by providing a piezoelectric material-based micro energy harvesting cluster system, its preparation method and application. The object of the present invention is to convert the vibration mechanical energy caused by air flow into electrical energy through piezoelectric materials, collect the energy in a cluster manner, and store it. By integrating organic flexible piezoelectric thin films with biomimetic structures, the present invention can avoid the characteristics of small output power and limited energy conversion efficiency of a small number of piezoelectric conversion devices, and convert mechanical energy into electrical energy as much as possible using vibration, without relying on frequency.

[0010] The object of the present invention is achieved by the following technical solutions:

[0011] The first object of the present invention is to provide a piezoelectric material-based micro energy harvesting cluster system. The piezoelectric material-based micro energy harvesting cluster system includes a plurality of piezoelectric micro energy harvesting units; each piezoelectric micro energy harvesting unit includes: an organic flexible piezoelectric thin film, a flexible electrode layer, and a packaging shell; the piezoelectric constant d of the organic flexible piezoelectric thin film 33 ≥30 pC / N, with a thickness of 200 nanometers to 5 micrometers, having both high flexibility and sensitivity, and can form a biomimetic structure; the sheet resistance of the flexible electrode layer ≤50 Ω / sq, which is attached to the upper and lower surfaces of the organic flexible piezoelectric thin film; the thickness of the packaging shell is 0.1 - 0.5 mm, and the organic flexible piezoelectric thin film and the flexible electrode layer are encapsulated in the packaging shell; the flexible electrode layer is connected to a lead wire; each piezoelectric micro energy harvesting unit is connected through a lead wire; the piezoelectric material-based micro energy harvesting cluster system further includes an energy management module; the energy management module is connected to the piezoelectric micro energy harvesting unit through a lead wire.

[0012] The biomimetic structure of the present invention can be prepared into many different shapes. For example, it can be made into a landscape and placed in the external environment. While greening the urban environment, it can also collect the energy in the external environment, providing energy for low-power electronic components such as street lights and traffic lights on both sides of the road, eliminating the need for additional power supply and saving electricity.

[0013] Further, the packaging shell is a common flexible plastic shell.

[0014] Further, the energy management module includes a circuit and an energy storage unit; the circuit is connected to the energy storage unit; the energy storage unit is connected to the circuit to charge the energy storage unit.

[0015] Further, the circuit is a rectifier circuit, adopting synchronous rectification technology and an adaptive threshold switching mechanism, with an AC-DC conversion efficiency ≥ 85%; the energy storage unit includes a micro lithium-ion battery and a micro-supercapacitor connected in parallel. The capacity of the micro lithium-ion battery is 100 - 500 mAh, and the capacity of the micro-supercapacitor is 1 - 10 F. The charge-discharge efficiency of the energy storage unit is ≥ 95%; the energy management module further includes a wireless energy transmission interface, which is connected to the energy storage unit. The wireless energy transmission interface supports wireless charging according to the Qi protocol, with a maximum transmission power of 2.5 W.

[0016] Further, the organic flexible piezoelectric film is a polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE)-based composite film; the material of the flexible electrode layer is a composite conductive material of silver nanowires and graphene.

[0017] Further, the material of the encapsulation shell is one or more of materials such as polyvinyl chloride, polyethylene, polypropylene, and polyurethane, and the surface is coated with a hydrophobic-self-cleaning composite coating, with a contact angle of the hydrophobic-self-cleaning composite coating ≥ 150°.

[0018] Further, the material of the hydrophobic-self-cleaning composite coating is a mixture of nano-silica particles and silicone resin (such as polydimethylsiloxane, PDMS).

[0019] Further, the shape of the bionic structure is a bionic shape, with both the length and width dimensions being 5 - 20 cm.

[0020] Further, the bionic shape is a leaf shape or a petal shape, etc.

[0021] Further, each piezoelectric micro energy harvesting unit is connected by leads into a topologically optimized three-dimensional series-parallel hybrid network; the three-dimensional series-parallel hybrid network includes multiple parallel branches, and each branch has multiple piezoelectric micro energy harvesting units connected in series.

[0022] Further, the energy management module is connected to the piezoelectric micro energy harvesting units forming a three-dimensional series-parallel hybrid network by leads, with a network impedance error ≤ 2%.

[0023] The second object of the present invention is to provide a preparation method for a piezoelectric material micro energy harvesting cluster system, and the preparation method includes the following steps:

[0024] S1. Dissolve the piezoelectric film raw material through methods such as dissolution in N,N-dimethylformamide (DMF) and blade coating to obtain an organic flexible piezoelectric film;

[0025] S2. Deposit two flexible electrodes on the upper and lower surfaces of the organic flexible piezoelectric thin film by spin coating, spraying or scraping respectively. The flexible electrodes form a flexible electrode layer to obtain a composite layer structure;

[0026] S3. Encapsulate and perform electrode lead processing to obtain a piezoelectric micro energy harvesting unit;

[0027] S4. Connect multiple piezoelectric micro energy harvesting units through leads to obtain a three-dimensional series-parallel hybrid network;

[0028] S5. Connect the three-dimensional series-parallel hybrid network with an energy management module to obtain a piezoelectric material-based micro energy harvesting cluster system.

[0029] Further, in step S5, connect the three-dimensional series-parallel hybrid network with the energy management module by rectification and filtering to obtain a piezoelectric material-based micro energy harvesting cluster system.

[0030] Further, when the system is deployed, the micro energy harvesting unit adopts a modular splicing design, supports hot plugging to replace faulty units, and the splicing interface meets the IP68 protection standard.

[0031] The third object of the present invention is to provide an application of a piezoelectric material-based micro energy harvesting cluster system, and use the piezoelectric material-based micro energy harvesting cluster system for intelligent landscape trees, building facades, vehicle-mounted devices, etc.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] Aiming at problems such as low output power, high frequency dependence, material and structure limitations, etc., the present invention proposes a brand-new piezoelectric micro energy harvesting cluster system, and its innovation points include:

[0034] (1) Flexible material and multi-scale bionic structure design: Adopt PVDF-TrFE-based organic flexible piezoelectric thin film (thickness 100 nanometers - 10 micrometers), break through the limitations of traditional rigid materials, and can be customized into bionic shapes such as leaf shape, petal shape, grass-like shape, etc., to fit diverse environmental requirements.

[0035] (2) Cluster integration technology: Integrate hundreds of piezoelectric units through a three-dimensional series-parallel method to form an energy harvesting cluster, significantly improving the total output power (up to the milliwatt level) and solving the bottleneck of insufficient output of a single unit.

[0036] (3) Wideband response ability: Through the nonlinear vibration characteristics of flexible materials (polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) - based composite thin films), effectively capture broadband vibrations and irregular vibrations caused by air flow, breaking through the dependence on fixed frequencies in the prior art.

[0037] (4) Environmental adaptability: The system can be integrated into scenarios such as landscape trees, building facades, and vehicle exteriors, combining functionality and aesthetics, filling the gaps in existing patented technologies in terms of flexible deployment and multi-functional integration.

[0038] The core advantages of the present invention are as follows:

[0039] (1) Output power improvement: Through cluster integration, the energy density per unit area is increased by 5-10 times compared with the traditional single-layer piezoelectric structure. The piezoelectric unit and the photovoltaic thin film work together, and the total energy density reaches 80 mW / m 2 .

[0040] (2) Enhanced frequency adaptability: It can adapt to a wide frequency vibration range of 0.1 Hz - 100 Hz, covering various scenarios such as natural wind and traffic vibration.

[0041] (3) Cost and flexibility advantages: Using polyvinylidene fluoride-trifluoroethylene-based film to replace the traditional PZT ceramic, the cost is reduced by 40%, and it has the characteristics of being bendable and cuttable, suitable for complex curved surface environments.

[0042] The present invention has the following characteristics:

[0043] 1. High output power: Through cluster integration and bionic design, the energy density is increased by 5 times compared with the traditional lead zirconate titanate single-layer piezoelectric structure. When the wind speed is 3 m / s, the output power reaches 75 mW;

[0044] 2. Wide applicability: It adapts to irregular mechanical energies such as natural wind and traffic disturbances;

[0045] 3. Environmentally friendly and multi-functional integration: The micro energy harvesting system can be customized into intelligent landscape trees, building exterior wall decorative panels, etc., combining beautification and energy harvesting functions. Description of the Drawings

[0046] Figure 1 It is a schematic diagram of the internal structure of a single piezoelectric micro energy harvesting unit of the piezoelectric material-based micro energy harvesting cluster system in Embodiment 1;

[0047] Figure 2 It is a schematic diagram of the structure of a single piezoelectric micro energy harvesting unit of the piezoelectric material-based micro energy harvesting cluster system in Embodiment 1, where (a) is a schematic diagram of the leaf-shaped encapsulation shell, and (b) is a perspective schematic diagram of the leaf-shaped piezoelectric micro energy harvesting unit;

[0048] Figure 3 It is a connection schematic diagram of multiple piezoelectric micro energy harvesting units of the piezoelectric material-based micro energy harvesting cluster system in Embodiment 1;

[0049] Figure 4It is a schematic structural diagram of the piezoelectric material micro-energy harvesting cluster system in Embodiment 1.

[0050] Explanation of the markings in the figure:

[0051] 1 - Organic flexible piezoelectric thin film, 2 - Flexible electrode layer, 3 - Encapsulation shell, 4 - Intelligent energy management module. Specific implementation manners

[0052] The present invention will be described in detail below in conjunction with specific embodiments, but it is by no means a limitation to the present invention. Features such as preparation means, materials, structures or composition ratios that are not clearly described in this technical solution are regarded as common technical features disclosed in the prior art.

[0053] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present invention are conventional reagents, methods, instruments and equipment in the art. Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0054] The polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) - based composite film is a self-made film. The material of the encapsulation shell 3 is polyphenylene sulfide (PPS), and the polyphenylene sulfide (PPS) is purchased from Zhejiang NHU Co., Ltd., with the model NHU-PPS200 / molecular weight of 45,000 - 60,000, and the surface is coated with a hydrophobic - self - cleaning composite coating. The contact angle of the hydrophobic - self - cleaning composite coating is ≥150°. The material of the hydrophobic - self - cleaning composite coating is a mixture of nano - silica particles and silicone resin (polydimethylsiloxane, PDMS). The mass ratio of nano - silica particles to silicone resin (polydimethylsiloxane, PDMS) is 1% - 2%. The hydrophobic - self - cleaning composite coating is attached to the surface of the encapsulation shell by soaking. The flexible electrode is a composite conductive material of silver nanowires and graphene, purchased from Hefei Microcrystal Co., Ltd., with the model WJF25. The specific preparation method of the polyvinylidene fluoride - trifluoroethylene (PVDF-TrFE) - based composite film is to dissolve the polyvinylidene fluoride - trifluoroethylene powder at room temperature using DMF. Among them, the mass ratio of PVDF-TrFE to DMF is 2% - 10%. The polyvinylidene fluoride - trifluoroethylene is purchased from Kermel.

[0055] Embodiment 1:

[0056] This embodiment provides a piezoelectric material micro - energy harvesting cluster system, specifically an intelligent landscape tree piezoelectric micro - energy harvesting cluster system.

[0057] The piezoelectric material-based micro energy harvesting cluster system is formed by connecting 1200 piezoelectric micro energy harvesting units in a three-dimensional series-parallel manner to obtain a three-dimensional series-parallel hybrid network, which is specifically connected by leads. Each piezoelectric micro energy harvesting unit is connected by leads to form a topologically optimized three-dimensional series-parallel hybrid network. The three-dimensional series-parallel hybrid network includes multiple parallel branches, and each branch serially connects multiple piezoelectric micro energy harvesting units. In this embodiment, each branch serially connects 30 pieces and has 40 parallel branches, with a total impedance error <1.5%.

[0058] Each piezoelectric micro energy harvesting unit includes: an organic flexible piezoelectric thin film 1, a flexible electrode layer 2, and a packaging shell 3. The flexible electrode layer 2, the organic flexible piezoelectric thin film 1, and the flexible electrode layer 2 arranged from top to bottom form a composite layer structure, which is encapsulated in the packaging shell 3. The upper and lower flexible electrode layers 2 are respectively connected to 2 leads. The piezoelectric constant d of the organic flexible piezoelectric thin film 1 33 ≥30 pC / N, and the thickness is 2.5 micrometers. The sheet resistance of the flexible electrode layer 2 ≤ 50 Ω / sq, and it adheres to the upper and lower surfaces of the organic flexible piezoelectric thin film 1. The thickness of the packaging shell 3 is 0.5 mm, and the organic flexible piezoelectric thin film 1 and the flexible electrode layer 2 are encapsulated in the packaging shell 3. The flexible electrode layer 2 is connected to the lead. Each piezoelectric micro energy harvesting unit is connected by leads. The piezoelectric material-based micro energy harvesting cluster system further includes an energy management module 4. The energy management module 4 is connected to the piezoelectric micro energy harvesting unit by leads. The surface of the packaging shell 3 is coated with a hydrophobic-self-cleaning composite coating, and the contact angle of the hydrophobic-self-cleaning composite coating ≥ 150°.

[0059] The width dimension of the bionic structure is 5 cm, and the length is about twice the width.

[0060] The shape of the bionic structure is leaf-shaped. The composite layer structure (organic flexible piezoelectric thin film 1, flexible electrode layer 2, encapsulation shell 3) is the main body of the leaf blade, and the lead wire is led out from the petiole of the leaf-shaped structure. The energy management module 4 includes a circuit and an energy storage unit; the circuit is connected to the energy storage unit; the energy storage unit is connected to the circuit. The circuit is a rectifier circuit, adopting synchronous rectification technology and an adaptive threshold switching mechanism, with an AC-DC conversion efficiency ≥ 85%, by using a high-performance synchronous rectification chip (Dongke VL-SR01) and combining an adaptive control strategy (such as pre-turn-off or dynamic threshold adjustment); the energy storage unit includes a parallel-connected micro lithium-ion battery and a micro supercapacitor. The capacity of the micro lithium-ion battery is 100 - 500 mAh, the capacity of the micro supercapacitor is 1 - 10 F, and the charge-discharge efficiency of the energy storage unit ≥ 95%; the energy management module 4 further includes a wireless energy transmission interface, which is connected to the micro lithium-ion battery and the micro supercapacitor. The wireless energy transmission interface supports Qi protocol wireless charging, with a maximum transmission power of 2.5 W.

[0061] The energy management module 4 is connected to the piezoelectric micro energy harvesting unit with a three-dimensional series-parallel hybrid network through a lead wire, and the network impedance error ≤ 2%.

[0062] The preparation method of the piezoelectric material micro energy harvesting cluster system includes the following steps:

[0063] S1. Dissolve the piezoelectric thin film raw material PVDF-TrFE powder through methods such as dissolution in N,N-dimethylformamide (DMF) and spin coating to form a film, etc., to obtain the organic flexible piezoelectric thin film 1, and the concentration of the PVDF-TrFE powder is 20 - 60 mg / L;

[0064] S2. Deposit 2 flexible electrodes on the upper and lower surfaces of the organic flexible piezoelectric thin film 1 respectively by spin coating, spraying or blade coating, with a thickness of 1 - 5 microns. The flexible electrodes form the flexible electrode layer 2 to obtain a composite layer structure;

[0065] S3. Use the hot pressing method (preheat at about 360 °C for 15 minutes and press at 0.1 - 0.2 MPa) to encapsulate the composite layer structure in the encapsulation shell 3 and perform electrode lead wire treatment to obtain a piezoelectric micro energy harvesting unit;

[0066] S4. Connect multiple piezoelectric micro energy harvesting units through lead wires to obtain a three-dimensional series-parallel hybrid network;

[0067] S5. Connect the three-dimensional series-parallel hybrid network to the energy management module 4 through an AC-DC converter to obtain a piezoelectric material micro energy harvesting cluster system.

[0068] In this embodiment, the internal structure schematic diagram of a single piezoelectric micro energy harvesting unit is asFigure 1 As shown. The composite layer structure of a single piezoelectric micro energy harvesting unit is encapsulated into a leaf-shaped shell to obtain a single leaf-shaped piezoelectric micro energy harvesting unit, as Figure 2 shown. Then, a single leaf-shaped piezoelectric micro energy harvesting unit is integrated onto a landscape tree, and then connected to an intelligent energy management module to complete the construction of a tree-shaped piezoelectric micro energy harvesting cluster system (intelligent landscape tree piezoelectric micro energy harvesting cluster system). The result is as Figure 3 、 4 shown.

[0069] The total output power of the cluster system is 75 mW (wind speed 3 m / s), which can continuously power a 10 W LED street lamp for 6 hours.

[0070] Example 2

[0071] This example provides a piezoelectric material-based micro energy harvesting cluster system, specifically a building exterior wall piezoelectric micro energy harvesting cluster system.

[0072] The difference between this example and Example 1 is that:

[0073] In this example, the composite layer structure of the piezoelectric micro energy harvesting unit is encapsulated into a 30 cm × 30 cm decorative panel, and a hydrophobic self-cleaning coating (contact angle 160°) is applied on the surface. Each panel integrates 36 piezoelectric micro energy harvesting units (thickness 4 mm) through a series-parallel circuit. 200 panels are installed on the south exterior wall of the building and networked through the ZigBee protocol. Every 10 panels are connected to an energy storage node (including a 500 mAh lithium battery + 5 F super capacitor). The energy storage node is embedded in the wall and accesses the building microgrid through a PoE power supply interface. The battery powers the device under high load, and the instantaneous peak is buffered by the capacitor.

[0074] Example 3

[0075] This example provides a piezoelectric material-based micro energy harvesting cluster system, specifically a vehicle self-powered piezoelectric micro energy harvesting cluster system.

[0076] The difference from Example 1 is that:

[0077] In this example, the piezoelectric film (thickness 2 μm) is cut into the contours of the A-pillar and the rearview mirror housing, and the encapsulation housing is made of carbon fiber reinforced polymer (thickness 0.2 mm). 50 piezoelectric micro energy harvesting units are embedded on both sides of the vehicle A-pillar and connected in parallel, and 20 piezoelectric micro energy harvesting units are embedded in each rearview mirror housing and connected in parallel. The total number is 140, and they are connected in parallel. The rectifier circuit uses GaN devices, and the AC / DC conversion efficiency reaches 88%, and the output DC voltage is stabilized at 5 V ± 2%. The energy storage unit uses a micro lithium-ion battery (300 mAh) and a 2 F super capacitor,

[0078] When the speed is 60 km / h, the piezoelectric material micro-energy harvesting cluster system outputs 120 mW, which can supply power to the tire pressure sensor (power consumption 5 mW) and the GPS module (power consumption 10 mW) in parallel.

[0079] Example 4: Bionic lawn piezoelectric micro-energy harvesting cluster system

[0080] This example provides a piezoelectric material micro-energy harvesting cluster system, specifically a bionic lawn piezoelectric micro-energy harvesting cluster system.

[0081] The difference from Example 1 is as follows:

[0082] In this example, the organic flexible piezoelectric thin film (1) is made into the shape of a grass leaf (length 15 cm, width 2 cm).

[0083] The encapsulation shell is made of TPU material (thickness 0.4 mm). 400 grass leaf units are laid per square meter of lawn and connected into a 10×40 array through a flexible PCB board. The grass leaf units are arranged vertically, that is, the length of the organic flexible piezoelectric thin film (1) is arranged along the vertical direction. One energy storage box (including a 1 kWh lithium battery pack + 20 F supercapacitor) is set every 10 square meters. The 100-square-meter lawn generates 1.2 kWh of electricity per day on average, which can supply power to 10 monitoring cameras (power consumption 5 W each) for about 20 hours. When the natural wind speed is 1 m / s, the output is 0.1 mW. The system preferentially stores the instantaneous trampling energy into the supercapacitor and stores the stable wind energy into the lithium battery.

[0084] The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and use the invention. It is obvious that those who are familiar with the technology in this field can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A piezoelectric material-based micro energy harvesting cluster system, characterized in that, The piezoelectric material-based micro energy harvesting cluster system includes a plurality of piezoelectric micro energy harvesting units; Each piezoelectric micro energy harvesting unit includes: an organic flexible piezoelectric film (1), a flexible electrode layer (2), and a packaging shell (3); The piezoelectric constant d of the organic flexible piezoelectric thin film (1) 33 is ≥ 30 pC / N and the thickness is from 200 nm to 5 μm; The sheet resistance of the flexible electrode layer (2) is ≤50Ω / sq, and it is attached to the upper and lower surfaces of the organic flexible piezoelectric film (1); The thickness of the packaging shell (3) is 0.1 - 0.5 mm, and the organic flexible piezoelectric film (1) and the flexible electrode layer (2) are encapsulated within the packaging shell (3); The flexible electrode layer (2) is connected to a lead wire; each piezoelectric micro energy harvesting unit is connected through a lead wire; The piezoelectric material-based micro energy harvesting cluster system further includes an energy management module (4); The energy management module (4) is connected to the piezoelectric micro energy harvesting unit through a lead wire.

2. The piezoelectric material-based micro energy harvesting cluster system according to claim 1, characterized in that The energy management module (4) includes a circuit and an energy storage unit; The circuit is connected to the energy storage unit; The energy storage unit is connected to the circuit to charge the energy storage unit.

3. The piezoelectric material-based micro energy harvesting cluster system according to claim 2, characterized in that The circuit is a rectifier circuit, adopting synchronous rectification technology and an adaptive threshold switching mechanism, with an AC-DC conversion efficiency ≥85%; The energy storage unit includes a parallel combination of a micro lithium-ion battery and a micro supercapacitor. The capacity of the micro lithium-ion battery is 100 - 500 mAh, the capacity of the micro supercapacitor is 1 - 10 F, and the charge-discharge efficiency of the energy storage unit is ≥95%; The energy management module (4) further includes a wireless energy transmission interface, and the wireless energy transmission interface is connected to the energy storage unit.

4. The piezoelectric material-based micro energy harvesting cluster system according to claim 1, wherein The organic flexible piezoelectric film (1) uses a polyvinylidene fluoride-trifluoroethylene-based composite film; The material of the flexible electrode layer (2) is a composite conductive material of silver nanowires and graphene.

5. The piezoelectric material-based micro energy harvesting cluster system according to claim 1, wherein The material of the packaging shell (3) is one or more of polyvinyl chloride, polyethylene, polypropylene, and polyurethane, and the surface is coated with a hydrophobic-self-cleaning composite coating, and the contact angle of the hydrophobic-self-cleaning composite coating is ≥150°; 6. The piezoelectric material-based micro energy harvesting cluster system according to claim 1, characterized in that The organic flexible piezoelectric film (1) adopts a bionic structure; The length and width dimensions of the bionic structure are 5 - 20 cm respectively.

7. The piezoelectric material-based micro energy harvesting cluster system according to claim 6, characterized in that The shape of the bionic structure is leaf-shaped, petal-shaped, or grass-like.

8. The piezoelectric material-based micro energy harvesting cluster system according to claim 1, characterized in that Each piezoelectric micro energy harvesting unit is connected through a lead wire to form a three-dimensional series-parallel hybrid network; The three-dimensional series-parallel hybrid network includes a plurality of parallel branches, and each branch serially connects a plurality of piezoelectric micro energy harvesting units.

9. A preparation method of a piezoelectric material-based micro energy harvesting cluster system according to any one of claims 1-8, characterized in that, The preparation method includes the following steps: Dissolve the piezoelectric film raw material in N,N-dimethylformamide and use a spin coating and film scraping process to obtain the organic flexible piezoelectric film (1); Deposit 2 flexible electrodes on the upper and lower surfaces of the organic flexible piezoelectric film (1) respectively by spin coating, spraying, or scraping. The flexible electrodes form the flexible electrode layer (2) to obtain a composite layer structure; Encapsulate the composite layer structure and perform electrode lead wire treatment to obtain a piezoelectric micro energy harvesting unit; Connect a plurality of piezoelectric micro energy harvesting units through lead wires to obtain a three-dimensional series-parallel hybrid network; Connect the three-dimensional series-parallel hybrid network to the energy management module (4) to obtain the piezoelectric material-based micro energy harvesting cluster system.

10. An application of a piezoelectric material-based micro energy harvesting cluster system according to any one of claims 1-8, characterized in that, Apply the piezoelectric material-based micro energy harvesting cluster system to smart landscape trees, building facades, and vehicle-mounted devices.

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