A wearable self-powered system based on flexible piezoelectric materials

Abstract

The application relates to a wearable self-powered system based on flexible piezoelectric materials, and belongs to the technical fields of new materials, self-power supply and energy utilization. The system comprises an energy conversion module (1), a power management module (2) and an energy storage module (3), the energy conversion module (1) and the power management module (2) are connected through wires, and the power management module (2) and the energy storage module (3) are collectively integrated on a PCB. The energy conversion module (1) prepared from a flexible piezoelectric composite material converts mechanical energy generated by the movement of human joints such as elbows and shoulders into electric energy, the electric energy is input through a rear-end circuit, and the collected energy is stored in a super capacitor. The system can efficiently collect the energy generated by human movement, is integrated on various human vital sign monitoring devices, and provides better use experience for users. The device has high electromechanical conversion performance and good energy storage capacity, and plays an important promoting role in the development of the self-powered wearable field.

Description

Technical Field

[0001] This utility model belongs to the fields of new materials, self-powered power supply, and energy utilization technology, and specifically relates to a flexible piezoelectric wearable self-powered system. Background Technology

[0002] With the rapid development of flexible material fabrication technology and self-powered technology, the construction of self-powered systems based on flexible materials, utilizing their adaptability to human skin, has become a hot topic in current energy utilization research. Specifically, by using special flexible materials as energy conversion modules, combined with hardware circuitry to regulate energy storage, the mechanical energy generated by human movement can be efficiently converted into electrical energy for energy utilization, effectively solving the problem of current microelectronic devices being completely dependent on external power sources.

[0003] Piezoelectric energy harvesters, utilizing the positive piezoelectric effect of piezoelectric materials, possess excellent electromechanical conversion performance, making them the ideal choice for building self-powered electromechanical conversion modules. Organic piezoelectric composites based on polydimethylsiloxane (PDMS) matrix surpass inorganic piezoelectric materials, offering advantages such as biocompatibility and durability, making them the preferred materials for energy conversion. The barium calcium zirconate titanate (BCZT) / PDMS flexible piezoelectric composite material utilizes BCZT nanoparticles to provide piezoelectric properties; PDMS has a Young's modulus of 1.24 MPa, close to that of human skin. Composite materials prepared using dielectrophoresis can yield piezoelectric materials with high transduction coefficients and good flexibility, making them well-suited for building wearable self-powered systems.

[0004] Combining self-powered systems with microelectronic products can solve problems such as the inconvenience of carrying external power sources, short lifespan, and cumbersome replacement processes, promoting energy-efficient product development and improving user experience. Furthermore, the application of self-powered technology can advance the field of energy recovery and utilization, providing new solutions for bioenergy utilization. Utility Model Content

[0005] The purpose of this invention is to provide a wearable self-powered system based on flexible piezoelectric materials. This system converts the mechanical energy generated by the movement of joints such as the elbow and shoulder into electrical energy through flexible piezoelectric composite materials. The collected energy is then stored in a supercapacitor after being controlled by a back-end circuit. This system can efficiently collect energy generated by human movement and can be integrated into various human vital sign monitoring devices, providing users with a better experience.

[0006] The technical solution to achieve the purpose of this utility model is as follows:

[0007] A wearable self-powered system based on flexible piezoelectric material includes three modules: an energy conversion module (1), a power management module (2), and an energy storage module (3). The energy conversion module (1) and the power management module (2) are connected by wires. The power management module (2) and the energy storage module (3) are integrated on a PCB board, so that the power management module (2) and the energy storage module (3) are electrically connected.

[0008] The energy conversion module (1) is made of a long strip of flexible BCZT / PDMS piezoelectric composite material, forming a folded structure that bends in the plane or a bow-shaped structure. The flexible BCZT / PDMS piezoelectric composite material energy harvester is formed.

[0009] The energy conversion module (1) is a planar bent bow-shaped structure formed by cutting away a portion of a whole piece of planar flexible BCZT / PDMS piezoelectric composite material. Preferably, three 1cm×6cm rectangular materials are cut alternately from a rectangular BCZT / PDMS piezoelectric composite material with a thickness of 0.15~0.20mm, so that the width of the bow-shaped energy collector is 1cm at each point; this structure generates more electrical energy through bending. The energy conversion module (1) has a silver layer with a thickness of 0.02 mm on both the top and bottom of the bow-shaped flexible BCZT / PDMS piezoelectric composite material to conduct current. The top or bottom of one end of the bow-shaped flexible BCZT / PDMS piezoelectric composite material energy harvester is the positive electrode, and the bottom or top of the other end is the negative electrode. Both the positive and negative electrodes are connected to the power management module (2) on the PCB board by wires (13). The outer surface of the bow-shaped flexible BCZT / PDMS piezoelectric composite energy harvester is encapsulated by insulating flexible tape (12), i.e., encapsulated according to the overall rectangular structure of the flexible BCZT / PDMS piezoelectric composite material. The insulating flexible tape (12) on the upper and lower surfaces of the BCZT / PDMS piezoelectric composite energy harvester is independent, which allows the bow-shaped flexible BCZT / PDMS piezoelectric composite energy harvester to deform freely in the sealed space and prevents external contact with the energy harvester material, greatly reducing the secondary loss of the collected energy. At the same time, the bow-shaped flexible BCZT / PDMS piezoelectric composite energy harvester encapsulated by insulating flexible tape (12) is attached to joints such as elbows and shoulders. The wire (13) extends independently out of the insulating tape (12). The wire (13) is electrically connected to the power management module (2).

[0010] The BCZT / PDMS in the energy conversion module (1) are all prepared by dielectrophoresis.

[0011] The power management module (2) is integrated on the PCB board and is used to regulate the electrical energy converted by the energy conversion module (1) in the form of current so as to collect energy; the energy storage module (3) is integrated on the same PCB board as the power management module, and the energy storage module (3) and the power management module (2) are electrically connected through the internal wiring of the PCB board.

[0012] The power management module (2) includes components such as an input capacitor, a low-loss buck converter, an output inductor, and an output capacitor. Commercially available components, such as the LTC3588 converter module, can be used. The low-loss buck converter is electrically connected to the output inductor, and the input capacitor is electrically connected to both the output inductor and the low-loss buck converter. The input capacitor is also electrically connected to the energy storage module (3). The output capacitor is coupled between the output voltage node of the low-loss buck converter and ground. The low-loss buck converter has pins that connect to the energy storage module (3) for connecting electronic products that require power.

[0013] The energy storage module (3) can be a commercially available product used to temporarily store electrical energy converted from energy, which can then be supplied to microelectronic products that require electrical energy. Furthermore, the energy storage module (3) mainly includes a 100µf small-volume supercapacitor.

[0014] The PCB board with power management module (2) and energy storage module (3) is encapsulated in a box (4), which is fixed to the waist with straps.

[0015] Multiple energy conversion modules (1) can be set at joints such as elbows and shoulders. The multiple energy conversion modules (1) are connected in series and then electrically connected to the power management module (2).

[0016] Compared with the prior art, the significant advantages of this utility model are:

[0017] (1) Compared with traditional lead-containing piezoelectric materials, the use of lead-free piezoelectric material BCZT as the energy harvester filler has the advantages of being non-toxic, more environmentally friendly, and human-friendly; PDMS is used as the matrix of flexible piezoelectric composite material, with a Young's modulus of 1.24 MPa, which is close to that of human skin, allowing it to fit well with human skin and have good biocompatibility, making it widely applicable to wearable devices; the flexible piezoelectric composite material BCZT / PDMS has extremely strong electromechanical conversion performance, and its transduction coefficient d 33 ×g 33 Above 10 pm 2 / N is an excellent choice for energy harvester materials; by making the flexible BCZT / PDMS piezoelectric composite material energy harvester into a bow shape, it can effectively amplify the deformation generated by human movement to the maximum extent, and can efficiently collect the mechanical energy generated by human movement and then convert it into electrical energy.

[0018] (2) By combining multiple modules and organically integrating the hardware and software, the energy collected by the flexible piezoelectric composite material energy harvester is stored in the supercapacitor to provide power to electrical appliances or energy-consuming components. Attached Figure Description

[0019] Figure 1 Layout diagram of a wearable self-powered system using flexible BCZT / PDMS piezoelectric materials;

[0020] Figure 2 This is a structural diagram of a flexible BCZT / PDMS piezoelectric composite energy harvester.

[0021] Figure 3 This is a component layout diagram on a PCB board. Detailed Implementation

[0022] The specific embodiments described below, with reference to the accompanying drawings, will further clarify the purpose, advantages, and features of the invention. The specific embodiments described below are for illustrative purposes only; any similar technical solutions are within the scope of protection claimed by this invention.

[0023] This invention provides a wearable self-powered system based on flexible BCZT / PDMS piezoelectric composite material. The principle layout of the entire system is as follows: Figure 1 As shown, the flexible piezoelectric composite energy harvester's core component is a complete bow-shaped flexible BCZT / PDMS piezoelectric composite material. The upper and lower surfaces of this material are coated with silver layers, and wires extend from these surfaces. When the human body moves at joints such as the shoulder and elbow, the resulting motion causes deformation of the BCZT / PDMS piezoelectric composite material. This deformation creates a potential difference, and the energy generated is transferred to the power management module via FPC wires. The flexible BCZT / PDMS piezoelectric composite energy harvester, used to harvest the body's mechanical energy, is integrated into the elastic straps of the shoulder and elbow supports, fitting snugly against the skin. Both the power management module and the energy storage module are integrated onto a single PCB board, which is placed in a plastic box (ABS is recommended) on the waist elastic strap. The two modules are connected via internal wiring on the PCB board. The backend power management module regulates the electrical energy converted by the energy conversion module in the form of current, ensuring successful energy storage in the energy storage module.

[0024] After rectification by the power management module, the current enters the energy storage module via the board-level main power input network. The energy storage module is specifically composed of a small-volume supercapacitor (100µF is recommended).

[0025] Figure 2 It is a flexible BCZT / PDMS energy harvester. When the human body moves, the shoulders and elbows constantly flex and extend, causing the BCZT / PDMS piezoelectric composite material to undergo large deformation, thereby converting it into electrical energy. Figure 3 Component 13 is an FPC wire directly connected to the energy harvester, leading out the positive terminal at the top and the negative terminal at the bottom; Component 1 is a bow-shaped flexible BCZT / PDMS piezoelectric composite energy harvester, which collects and converts human mechanical energy into electrical energy and is the core component of the system. This component is coated with a 0.02mm silver layer on both sides to conduct current, transferring the electrical energy collected and converted by the bow-shaped flexible BCZT / PDMS piezoelectric composite energy harvester to the back-end power management module; Component 12 is an insulating encapsulation component. It is recommended to use insulating tape to encapsulate the device to prevent external contact with the energy harvester material, greatly reducing secondary energy loss.

[0026] A structural diagram of a flexible BCZT / PDMS piezoelectric composite energy harvester is shown. The bow-shaped flexible BCZT / PDMS piezoelectric composite material in the diagram primarily functions to harvest the mechanical energy generated by human movement and convert it into electrical energy. This bow-shaped flexible BCZT / PDMS piezoelectric composite material is composed of a single piece of flexible BCZT / PDMS piezoelectric composite material, specifically three rectangular pieces of material cut alternately from a rectangular BCZT / PDMS piezoelectric composite material. The width of each part of the bow-shaped energy harvester is 1cm; preferably, three 1cm × 6cm rectangular pieces are cut from a 7cm × 15cm rectangular material. This bow-shaped energy harvester design possesses superior mechanical properties, optimizes stress distribution, and doubles the output voltage of a rectangular energy harvester, effectively improving the electromechanical conversion efficiency of the energy harvester.

[0027] Figure 3 It is a component layout diagram on a PCB board. Figure 3 The "+" and "-" signs are connected to the red and blue wires of the FPC wires respectively, thereby connecting the positive and negative terminals of the energy conversion module (3); The power management module includes input capacitors, a low-loss buck converter (the recommended micro-power energy harvesting unit is LTC3588-1), an output capacitor (the recommended capacitor is 10µf), and a switching inductor (the recommended inductor is 10µH). The recommended input capacitors are 1µf (preferred in this application) and 4.7µf. Figure 3 C1 is a 100µf small-volume supercapacitor that constitutes the energy storage module and is used to temporarily store the energy converted by the energy harvester. Figure 3 C2 and C4 are the input capacitors, 1µF and 4.7µF respectively. Figure 3U1 is the low-loss buck converter LTC3588-1; Figure 3 C3 is the output capacitor, 10µF. Figure 3 L1 is the output inductor with a capacity of 10µH. The power management module, consisting of the input capacitor, low-loss buck converter, output capacitor, and output inductor, is used to regulate the electrical energy converted by the energy conversion module in the form of current for energy harvesting.

[0028] The power management module comprises a circuit consisting of input capacitors (1µF and 4.7µF are recommended), a low-loss buck converter (LTC3588-1 is recommended as the micro-power harvesting unit), an output capacitor (10µF is recommended), and a switching inductor (10µH is recommended). Specifically, the LTC3588 chip (corresponding to U1 in the diagram) has multiple pins, including PGOOD, EN, D0, D1, Vin2, VouT, SW, VIN, CAP, PZ2, and PZ1. The CAP pin is coupled to another capacitor (1µF, corresponding to C2) for internal regulation; the Vin2 pin is coupled to a capacitor (4.7µF, corresponding to C4) for voltage input; the SW pin is coupled to an inductor (10µH) for switching; and the VouT pin provides output voltage feedback. The LTC3588-1 includes an energy sensor interface that programs the output voltage value via digital control signals D0 and D1. The corresponding D0 and D1 pins receive external digital signals and configure the output voltage based on combinations of their logic states. Specifically, when both D1 and D0 are logic low, the output voltage is set to 1.8 volts; when D1 is logic low and D0 is logic high, the output voltage is set to 2.5 volts; when D1 is logic high and D0 is logic low, the output voltage is set to 3.3 volts; and when both D1 and D0 are logic high, the output voltage is set to 3.6 volts. This configuration allows the circuit to flexibly adapt to the voltage requirements of different sensors or loads. The circuit also includes an output capacitor (10 MF, corresponding to C3) coupled between the output voltage node and ground to smooth the output voltage and reduce ripple. The PGOOD pin provides a power-good signal, indicating whether the output voltage is within the normal range. The EN pin enables or disables the memory module.

Claims

1. A wearable self-powered system based on flexible piezoelectric materials, characterized in that, It includes three modules, specifically: energy conversion module (1), power management module (2) and energy storage module (3). The energy conversion module (1) and power management module (2) are connected by wires. The power management module (2) and energy storage module (3) are integrated on the PCB board, so that the power management module (2) and energy storage module (3) are electrically connected. The energy conversion module (1) is made of a long strip of flexible BCZT / PDMS piezoelectric composite material, forming a folded structure that bends in the plane or a bow-shaped flexible BCZT / PDMS piezoelectric composite material energy harvester.

2. A wearable self-powered system based on flexible piezoelectric materials according to claim 1, characterized in that, The energy conversion module (1) is a planar bent bow-shaped structure formed by cutting off a portion of a whole piece of planar flexible BCZT / PDMS piezoelectric composite material. Three 1cm×6cm rectangular materials are cut out alternately from a 7cm×15cm rectangular BCZT / PDMS piezoelectric composite material with a thickness of 0.15~0.20mm, so that the width of each part of the bow-shaped energy collector is 1cm.

3. A wearable self-powered system based on flexible piezoelectric material according to claim 1, characterized in that, The energy conversion module (1) has a 0.02mm thick silver layer on both the top and bottom of the bow-shaped flexible BCZT / PDMS piezoelectric composite material to conduct current. The top or bottom of one end of the bow-shaped flexible BCZT / PDMS piezoelectric composite material energy harvester is the positive electrode, and the bottom or top of the other end is the negative electrode. Both the positive and negative electrodes are connected to the power management module (2) on the PCB board by wires (13).

4. A wearable self-powered system based on flexible piezoelectric materials according to claim 1, characterized in that, The outer surface of the bow-shaped flexible BCZT / PDMS piezoelectric composite energy harvester is encapsulated by insulating flexible tape (12), i.e., encapsulated according to the overall rectangular structure of the flexible BCZT / PDMS piezoelectric composite material. The insulating flexible tape (12) on the upper and lower surfaces of the BCZT / PDMS piezoelectric composite energy harvester is independent, which allows the bow-shaped flexible BCZT / PDMS piezoelectric composite energy harvester to deform freely in the sealed space and prevents external contact with the energy harvester material, greatly reducing the secondary loss of the harvested energy. At the same time, the bow-shaped flexible BCZT / PDMS piezoelectric composite energy harvester encapsulated by insulating flexible tape (12) is attached to the elbow and shoulder joints; the wire (13) extends independently out of the insulating flexible tape (12); the wire (13) is electrically connected to the power management module (2).

5. A wearable self-powered system based on flexible piezoelectric material according to claim 1, characterized in that, The power management module (2) is integrated on the PCB board to regulate the electrical energy converted by the energy conversion module (1) in the form of current so as to collect energy; The energy storage module (3) is integrated on the same PCB board as the power management module. The energy storage module (3) and the power management module (2) are electrically connected through the internal wiring of the PCB board.

6. A wearable self-powered system based on flexible piezoelectric material according to claim 1, characterized in that, The power management module (2) includes an input capacitor, a low-loss buck converter, an output inductor, and an output capacitor assembly. The low-loss buck converter is electrically connected to the output inductor, and the input capacitor is electrically connected to both the output inductor and the low-loss buck converter. The input capacitor is electrically connected to the energy storage module (3). The output capacitor is coupled between the output voltage node of the low-loss buck converter and ground. The low-loss buck converter has pins that connect to the energy storage module (3) for connecting electronic products that require power.

7. A wearable self-powered system based on flexible piezoelectric material according to claim 1, characterized in that, The energy storage module (3) is used to temporarily store the electrical energy converted from energy, and then supply it to microelectronic products that need to consume electrical energy. The energy storage module (3) mainly includes a 100µf small volume supercapacitor.

8. A wearable self-powered system based on flexible piezoelectric material according to claim 1, characterized in that, The PCB board with power management module (2) and energy storage module (3) is encapsulated in a box (4), which is fixed to the waist with straps.

9. A wearable self-powered system based on flexible piezoelectric material according to claim 1, characterized in that, Multiple energy conversion modules (1) are set at the elbow and shoulder joints. The multiple energy conversion modules (1) are connected in series and then electrically connected to the power management module (2).

Images