Piezoelectric Energy Harvester Research Articles

Cantilever configurations in vibration-based piezoelectric energy harvesting: a comprehensive review on beam shapes and multi-beam formations

Abstract Vibration-based energy harvesting technology is a well-established research area that has attracted tremendous interest over the last decade. This interest is primarily owing to its extension into a wide range of engineering domains, particularly in microelectromechanical systems. The cantilever beam is the most common and widely used model for vibration-based energy harvester, driven by two key factors: (a) simplicity in design, and (b) high output power density. Numerous studies over the years have focused on optimizing the cantilever beam design to increase output power capacity and/or widen the frequency bandwidth of the harvester. While researchers have proposed a plethora of cantilever beam configurations for specific purposes (e.g. low-frequency harvesting, multi-directional frequency harvesting, etc), there is a notable lack of detailed literature on the types and configurations of cantilever beams. This gap hinders researchers from gaining a comprehensive understanding of the cantilever beams already introduced. Following the need, in this article a comprehensive review is made to list the types of cantilever beams proposed by the researchers over the years. This review covers the working principles of piezoelectric energy harvesting, analyses existing solutions geared towards increasing power output and widening working frequency, and discusses diverse configurations including single and multiple beam setups. The listed beams are categorized based on their structural shape and organization such that it can be helpful for a reader to anticipate which cantilever beam design can be suitable for a specific need. Power output capacity and operating frequency for every beam design are also presented in a tabular form, under each beam category. This would enable the researchers to tailor their designs for specific applications, enhance material efficiency, drive innovation, and open new application possibilities.

Exploring dynamics, stability, and bifurcation in a coupled damped oscillator with piezoelectric energy harvester

In this work, we analyze and investigate the mathematical modeling of a dynamical system connected to a piezoelectric device. Piezoelectric transducers are established as highly effective energy harvesting (EH) devices, often employed in real-world mechanical systems. The structure of the dynamical model contains a damped Duffing oscillator acting as the major component, which is connected to an unstretched pendulum and simultaneously to the piezoelectric harvester. To derive the governing equations of motion (EOM), Lagrange’s equations are applied based on the system’s generalized coordinates, in which they are analytically solved using the multiple scales (MS) perturbation method up to the second approximation. Moreover, the solutions achieved are compared with numerical ones to increase transparency and demonstrate the accuracy of the approximate solutions. In addition, comprehensive graphical representations have been produced to investigate the nonlinear stability of the modulation equations. Phase portraits, bifurcation diagrams, and Lyapunov spectra are displayed to depict various system behaviors, alongside Poincaré maps for deeper understanding. The various stability ranges are also explored and discussed. In conclusion, mechanical vibrations are transformed into electricity by the piezoelectric transducer connected to the dynamic model, which has widespread applications and includes crystal oscillators, medical ultrasound, gas igniters, and displacement transducers.

Design and Modeling of Micro-Scale Piezoelectric Vibration Energy Harvester for Charging Pacemaker Battery

Design and Modeling of Micro-Scale Piezoelectric Vibration Energy Harvester for Charging Pacemaker Battery

An enhanced broadband piezoelectric energy harvester via elastic amplification structure for multidirectional vibration

Abstract Vibration energy harvesting using a piezoelectric mechanism has significant potential for powering wireless sensors. However, most current vibration energy harvesters face limitations such as bidirectionality, narrow bandwidth, and high operating frequencies. To address these issues, we propose an enhanced broadband piezoelectric energy harvester utilizing an elastic amplification structure for multidirectional vibration (EB-PVEH). By utilizing the multidirectional rotation capacity of the excitation block and the amplified foundation excitation provided by springs, the EB-PVEH effectively captures broadband vibrations in 2D space under low-frequency excitation. Additionally, its design features long-term durability, as the piezoelectric beams are smoothly excited by the pendulum-induced motion of the block without a tip mass. The practical feasibility and the impact of structural parameters on the output behavior of EB-PVEH were investigated through theoretical analysis and experimental testing. The results revealed that the introduction of springs dynamically amplified the harnessed electrical power output. Moreover, EB-PVEH could harvest the multidirectional vibration, and it exhibited different power-generating characteristics in various directions. Furthermore, the resonance frequency could be efficiently tuned by adjusting the flexible arm length and proof mass, with different optimal arm lengths identified for each vibration direction to maximize working bandwidth. The harvester achieved an optimal output power of 3.98 mW. Practical applications, such as charging a capacitor by driving an e-bike or a bike, demonstrate the potential of the proposed harvester to provide power for micro-electrical devices.

Multisource energy harvesting using (Ba,Ca)(Zr,Ti)O3 oscillating under temperature gradient

AbstractThe concept of multisource energy harvesting has attracted attention in order to harvest multiple types of energy in a single material. In this work, Pb‐free (Ba,Ca)(Zr,Ti)O3 (BCZT) ceramics were used to investigate a combination of piezoelectric and pyroelectric energy harvesting behavior. The temperature dependence of the permittivity and the pyroelectric coefficient was measured, and the pyroelectric properties of BCZT were expected to improve near its orthorhombic–tetragonal phase transition temperature TO–T (∼40°C). The output voltage and current were measured using a BCZT plate, where the BCZT was oscillated under a temperature gradient to apply mechanical stress and temperature fluctuation simultaneously. The measured output voltage from the combined piezo‐ and pyroelectric contributions at a frequency of 2 Hz and with a load resistance of 10 MΩ was 1.4 times higher than the sole piezoelectric output voltage. The resulting combined output voltage was confirmed by finite element simulation.

An ultralow-frequency high-efficiency rotational energy harvester with bistability principle and magnetic plucking mechanism

In this paper, we propose an energy harvester that overcomes the bottleneck problem under ultralow-frequency rotational motion. The harvester consists of bistable dual piezoelectric energy harvesters (BD-PEH) with the magnetic plucking mechanism. The driving magnet is introduced to provide the magnetic plucking to BD-PEH. Therefore, the BD-PEH can operate at high-frequency vibrations across the potential well under ultralow-frequency rotation, which enhances energy harvesting efficiency. A numerical model of the harvester is developed, and the model results are in agreement with the experimental results. The effect of the depth of the potential well on the performance of the harvester is analyzed. The deeper the potential well, the higher the energy output, but it will reduce the bandwidth of the harvester. The experimental results show that the highest average power output is 0.81 mW at 1.2 Hz. In conclusion, the energy harvester proposed in this paper can generate enough energy to drive low-power electronic devices under ultralow-frequency rotational motion.

Multi-directional and multi-modal vortex-induced vibrations for wind energy harvesting

A conventional vortex-induced vibration (VIV)-based energy harvester is typically restricted to capturing wind energy from a very limited range of wind directions, making it inefficient in varying wind conditions. This Letter proposes a tri-section beam configuration for VIV-based piezoelectric energy harvester to enable harnessing wind energy from varying incident angle with different vibration modes being triggered. The finite element analysis investigates the tri-section beam harvester's mode shapes and natural frequencies. A wind tunnel experiment is conducted for a comparative study of the energy output performance of the harvesters with straight and tri-section beams. The findings show that the proposed harvester with the tri-section beam can efficiently capture wind energy from a much wider range of incident angles, as opposed to the specific limited directions of its counterpart with the straight beam. The proposed harvester can also widen the lock-in speed range with a higher bending mode being triggered and achieve the optimal output power of 1.388 mW when the proposed harvester works in the second mode at a higher natural frequency, superior to that of its counterpart (0.386 mW) that can only work in the first mode. The proposed configuration sheds light on developing multi-directional and multi-modal VIV-based energy harvesters adapted to wind conditions in natural environments.

Evaluating the efficacy of lead-free piezoelectric materials in microcantilever based vibration energy harvesters

Abstract The piezoelectric materials have been extensively utilized in various applications, such as sensors, actuators, and energy harvesters. This study evaluates the performance of six lead-free piezoelectric materials- aluminium nitride (AlN), barium titanate (BaTiO3), lithium niobate (LiNbO3), lithium tantalate (LiTaO3), polyvinylidene fluoride (PVDF), and zinc oxide (ZnO) in MEMS-based piezoelectric vibration energy harvesters (PVEHs) using cantilever configurations. Finite element analysis via COMSOL Multiphysics was employed to assess the deflection, voltage, and power outputs of these materials at their resonance frequencies, both with and without proof masses. The results indicate that BaTiO3 and PVDF cantilevers exhibited the highest voltage outputs, reaching 207.14 mV and 202.07 mV, respectively, with AlN also showing comparable performance at 184.72 mV. ZnO-based cantilevers demonstrated the highest power output of 1.35 nW without proof masses and 190.5 nW with proof masses, indicating its potential for high-power applications. The addition of proof masses generally reduced resonant frequencies but enhanced power outputs, like for ZnO. This comprehensive analysis underscores the critical impact of material selection and structural modifications on the efficiency of PVEHs, with BaTiO3, PVDF, and ZnO emerging as the most promising candidates for optimizing energy harvesting devices. This research lays a foundation for further advancements in piezoelectric MEMS technology, aiming for more efficient energy harvesting solutions.

A self-powered interface circuit for piezoelectric and photovoltaic energy extracting

This paper presents a high-efficiency multi-source energy harvesting system consisting of a piezoelectric rectifier, a photovoltaic maximum power point tracking circuit and a fast self-startup circuit for powering wireless sensor nodes. Synchronous electric charge extraction techniques (SECE) are utilized to extract the piezoelectric energy when the deflection of piezoelectric energy harvester beam reaches its peak. Compared with other circuits, the proposed SECE technique can achieve piezoelectric and photovoltaic extraction simultaneously with a concise flyback topology structure. A novel maximum power point tracking method is adopted to enhance the robustness of operation against changing operating condition and improve the photovoltaic extraction efficiency. To remove the need for a battery, a simple and efficient self-startup circuit is introduced. The energy harvesting circuit is fabricated in 180 nm CMOS process. Measurement results show a fast self-startup at a relatively low light intensity of 120 lux is realized. The energy harvesting circuit is capable of outputting 189 μW power at 3.3 V piezoelectric open circuit voltage and 0.6 V photovoltaic input voltage.

Defect Engineering with Rational Dopants Modulation for High-Temperature Energy Harvesting in Lead-Free Piezoceramics

HighlightsThe solution limit of manganese ion in BiFeO3–BaTiO3 (BF–BT) was determined by combining multiple advanced characterization methods.The defect engineering associated with fine doping can realize the co-modulation of polarization configuration, iron oxidation state and domain orientation.The BF–BT–0.2Mn piezoelectric energy harvester shows excellent power generation capacity at 250 °C, which is an important breakthrough for lead-free piezoelectric devices.

Metaharvesting: emergent energy harvesting by piezoelectric metamaterials

Vibration energy harvesting is a technology that enables electric power generation by augmenting vibrating materials or structures with piezoelectric elements. In a recent work, we quantified the intrinsic energy-harvesting availability (EHA) of a piezoelectric phononic crystal (Piezo-PnC) by calculating its damping ratio across the Brillouin zone and subtracting off the damping ratio of the corresponding non-piezoelectric version of the phononic crystal. It was highlighted that the resulting quantity indicates the amount of useful energy available for harvesting and is independent of the finite structure size and boundary conditions and of any forcing conditions. Here, we investigate the intrinsic EHA of two other material systems chosen to be statically equivalent to a given Piezo-PnC: a piezoelectric locally resonant metamaterial (Piezo-LRM) and a piezoelectric inertially amplified metamaterial (Piezo-IAM). Upon comparing with the intrinsic EHA of the Piezo-PnC, we observe an emergence of energy-harvesting capacity, a phenomenon we refer to as metaharvesting. This is analogous to the concept of metadamping, except the quantity evaluated is associated with piezoelectric energy harvesting rather than raw dissipation. Our results show that the intrinsic EHA is enhanced by local resonances and enhanced further by inertial amplification. These findings offer a new paradigm for the design—at the fundamental level—of architectured piezoelectric materials with superior energy-harvesting capacity.

Deep adversarial learning models for distribution patterns of piezoelectric plate energy harvesting

This paper presents a novel approach utilizing piezoelectric plate structures with random electrode distribution patterns for energy harvesting applications across various vibration modes. For the first time, leveraging electromechanical Finite Element Analysis (eFEA) and data extraction techniques, we investigate the integration of conditional Generative Adversarial Networks (cGAN)-based dynamic models for this purpose. The cGAN offers an effective technique for generating realistic synthetic data conditioned on input parameters, thereby enabling the creation of diverse and representative datasets for training energy harvesting systems. The integration of eFEA with cGAN opens up new possibilities for optimizing the design and performance of piezoelectric energy harvesters across various applications. Specifically, we explore four distinct cGAN models-based mechanics of energy harvesters by deploying distribution patterns. These models include training data generated by stacking simultaneously mode images, utilizing separate cGAN models for each mode, labeling images by mode, and concatenating all mode images into one. Our study focuses on assessing the effectiveness of these models in minimizing loss in cGAN-based power generation and predicting Structural Similarity Index Measure (SSIM) values, and more importantly, identifying the predicted data point outputs from the generated pixel image extractions. By analyzing the generated data from numerical model and its application in deep learning, we aim to enhance the understanding of the effects of distribution patterns and image processing techniques for optimal power generation and the effectiveness of piezoelectric energy harvesting systems across different vibration modes. The studies explore how different distribution patterns affect the power harvesting efficiency and frequency bandwidth, utilizing the generated datasets.

Energy harvesting from wake-induced vibration of flexible flapper behind a bluff body

Piezoelectric energy harvesting from ambient vibrations offers a promising small-scale energy generation strategy, with wake-induced vibration of flexible structures being an ideal candidate. This study examines a bluff body followed by a fully flexible piezoelectric flapper in a viscous free-stream flow using an in-house discrete forcing immersed boundary method-based fluid-structure-electric energy solver for parametric investigation. Different vortex shedding regimes are identified based on vortex formation around the flexible flapper. The complex and interdependent spatiotemporal dynamics of the wake and flexible body dictated by parameters such as bending rigidity and the gap space between the flapper and bluff body result in various deformation profiles, influencing the strain rate and output power. The study also investigates the independent variation of flapper length and its impact on vortical arrangements and flexibility, introducing different oscillation modes. The present study takes a nuanced view of the overall dynamics and their mutual effect on the power output, unlike most existing studies where enhancing the amplitude and frequency of oscillations for an optimal output was the main concern. Factors such as flapper curvature, its asymmetry, and periodicity have been especially highlighted in the context of the output and the corresponding parametric spaces investigated. Interestingly, the increase in piezo-flapper length has seen a reduction in output, though it was instrumental in bringing symmetry back. The study offers comprehensive insights into ideal harvesting regimes and the underlying dynamical mechanisms and can contribute toward the design of future energy harvesting devices.

Energy harvesting properties for potassium-sodium niobate piezoceramics through synergistic effect of phase structure and texturing engineering

In order to address the energy dilemma and meet environmental protection requirements, it is an urgent need to develop lead-free piezoelectric energy harvesters (PEHs). However, the low output power density has seriously hindered the application of lead-free piezoceramics as high efficiency energy harvesters. To solve above question, the combination of phase structure regulation and texturing technique in the K0.5Na0.5NbO3-xBi0.5Na0.5ZrO3-0.5%wtBiFeO3 (KNN-xBNZ) ceramics was adopted in this work. Because of both the Rhombohedral-Orthorhombic-Tetragonal (R-O-T) multiphases coexistence and texturing engineering, an ultrahigh piezoelectric activity quality factor d33×g33 ∼ 18324 ×10-15 m2·N-1 was achieved in the textured KNN-0.05BNZ (T-KNN-0.05BNZ) ceramics, which is about third times higher than that of random KNN-0.05BNZ (R-KNN-0.05BNZ) (d33×g33 ∼ 6672 ×10-15 m2·N-1) ones. A high output power of ∼ 0.32 mW was also obtained in the T-KNN-0.05BNZ ceramics by cantilever beam-based energy harvester devices under the resonance frequency of 75 Hz and matched RL of 1.2 MΩ, suggesting that the T-KNN-0.05BNZ ceramics have a great potential for application in the PEHs devices. This result also reveals that the combination of phase structure regulation and texturing technique is an effective way to achieved a high energy harvesting performances.

A centrifugal spring mechanism empowers self-adjusting in piezoelectric wind energy harvesting

Piezoelectric wind energy harvesters (PWEHs) offer promises in sustainable green energy supply for micropower electronics. However, traditional PWEHs encounter challenges in terms of high start-up wind speeds, subpar output performance, and narrow bandwidth, hampering their widespread adoption. To enhance the energy capture efficiency, a novel self-adjusting PWEH integrating a centrifugal spring mechanism (CSM) is presented. The CSM consists of a sliding rod, a 304 stainless steel spring, an exciting magnet, and a mass block. Additionally, the PWEH employs a vertical-axis blade design, allowing it to capture wind from different directions. Via theoretical analyses, finite element simulations, and experiments, key parameters of the PWEH are optimized including the CSM additional mass, spring wire diameter, and the configuration of multi-frequency piezoelectric transducers. Results demonstrate that the optimized PWEH works at 1.5m/s and generates 0.45mW, 2.742mW, and 5.973mW at wind speeds of 2m/s, 3.3m/s, and 4.75m/s, respectively. Compared to the unoptimized PWEH, the introduction of the CSM results in an 80.7% enhancement in open-circuit voltage and a 90.9% increase in short-circuit current. Additionally, by utilizing four pairs of piezo-transducers with different resonance frequencies (6.83Hz, 9.38Hz, 12.1Hz, and 14.8Hz), the resonance bandwidth of the PWEH is expanded to 1.5~5.5m/s. The feasibility of PWEH for powering signage, electronic screens, and Bluetooth thermohygrometer is demonstrated. The potential of PWEH in constructing high-precision intelligent wind speed monitoring systems is tested via convolutional neural networks. The study offers a strategy for designing the PWEH for both powering of the microelectronic devices, and intelligent sensing and monitoring of wind.

Advanced piezoelectric fluid energy harvesters by monolithic fluid–structure–piezoelectric coupling: A full-scale finite element model

A full-scale finite element model is presented for monolithic fluid–structure interaction (FSI) simulations of thin-walled piezoelectric fluid energy harvesters (PFEHs). Unlike widely used beam/plate-based models, our model employs a solid finite element discretization to precisely represent the complex PFEH designs involving microstructured transducers and non-uniform cantilevers. These features, plus the local FSI effects, are often ignored by simplified models. We applied the Galerkin method to formulate the weak form of the mixed equation system, integrating the flow dynamics, the geometrically nonlinear cantilever, the piezoelectric components, the electrode, and the output circuit within a closed-circuit electro-mechanical coupled system. The coupling of the multiple domains is achieved through boundary-fitted discretization within a monolithic scheme, using shifted-Crank–Nicolson temporal integration. This work explored implementing piezoelectric FSI systems within the FEniCS-based TurtleFSI library, and experimented techniques such as employing penalty functions for achieving electrode components with uniform electric potentials. We investigated various advanced PFEH features, including the baseplate design, the arrangement and microstructure of the piezoelectric components, and their influence on the system's dynamic and energy output behavior. The results confirmed the model's key advantages: full-scale modeling allows the integration of complex base structures and transducer microstructures in PFEH design. Combined with monolithic FSI coupling, it offers greater versatility, supporting a wider range of fluid environments and configurations in both wind and hydropower harvesting. Additionally, the modeling strategy can be intended not only to enhance power output, but also to minimize material usage, reduce mechanical fatigue, and extend the operational lifespan of PFEH systems.

Dual fillers ZrO2/BaTiO3 incorporated PVDF-HFP nanofiber composite for enhanced piezoelectric energy harvesting and piezo catalytic reduction of hexavalent chromium

A novel Piezoelectric Nanogenerator (PENG) was designed and fabricated using electrospun nanocomposite fibers of Poly(vinylidene fluoride)-co-hexafluoropropylene (PVDF-HFP) with Barium Titanate (BaTiO3) and Zirconium Oxide (ZrO2) as dual fillers. ZrO2 fillers were incorporated at varying loadings into the PVDF-HFP polymer matrix to produce the PBZ nanocomposite fibers. The synergistic effect of BaTiO3 and ZrO2 significantly enhanced the piezoelectric performance of the resulting PBZ composite. The dual fillers also induced the nucleation of the β-phase in the nanofiber composite, which further improved its piezoelectric properties. This enhancement rendered the composite highly effective for dual applications: energy harvesting and the piezocatalytic reduction of hexavalent chromium (Cr(VI)). The PENG exhibited an open-circuit voltage of 6.3 V, a current of 0.67 µA, and a power density of 30.91 mW/m². The device was also tested in real-world scenarios, such as finger tapping and shoe sole applications, additionally it successfully powered up to five LEDs and charged a 1–2.2 μF capacitor to approximately 1–3 V under an external load of 1 N at 2 Hz. In addition to energy harvesting, the PBZ nanofibers demonstrated remarkable piezocatalytic activity by converting highly toxic Cr(VI) to Cr(III), which is biologically essential in trace amounts. The PBZ nanofiber mats achieved an impressive Cr(VI) reduction rate of up to 90.1 % under acidic conditions within 20 minutes and were recyclable for up to five cycles without loss of efficiency. Furthermore, Density Functional Theory (DFT) calculations, focusing on the Density of States (DOS), were performed to elucidate the underlying mechanisms contributing to the observed improvements in piezoelectric and piezocatalytic performance.

A Review of Piezoelectric Energy Harvesting in Shape and Array Configuration

A Review of Piezoelectric Energy Harvesting in Shape and Array Configuration

Innovative Wearable Electronics: Next-Generation Nitrogen-Doped Lutetium-Carbon Microspheres Composites for Robust Energy Harvesting.

In the quest to advance wearable electronics, this study presents a novel method using nitrogen-doped lutetium-carbon microspheres (N, Lu-CMS) for high-performance piezoelectric energy harvesting. The synthesis of N, Lu-CMS begins with the polymerization of sucrose, followed by the preparation of N, Lu-CMS metal complexes through the incorporation of lutetium (III) nitrate hydrate and thiourea, yielding a black powder product. The wearable electronic device is designed with a silicon rubber (SR) matrix, reinforced with 0D fillers such as N, Lu-CMS, or molybdenum disulfide (MoS₂). Mechanical testing revealed a significant improvement in compressive modulus, reaching 3.7MPa (N, Lu-CMS) at a concentration of 3 parts per hundred rubber (phr). Electromechanical assessments demonstrated efficient energy conversion, while biomechanical analysis, including thumb pressing tests, showed a notable increase in output voltage, peaking at ≈285mV (N, Lu-CMS) at 3 phr. This research provides a foundation for future engineering applications, particularly in electronic packaging for wearable electronics and smart devices, underscoring the significant impact of N, Lu-CMS in this emerging field. The surface power density achieved is 0.026 nWcm- 2 (N, Lu-CMS) and 0.0056 nWcm- 2 (Hybrid). Lastly, the conversion efficiency is 6.26% for N, Lu-CMS, and 1.05% for the hybrid system.

Enhanced energy harvesting in low-velocity water by downstream interference for piezoelectric energy harvester

The vibration of a single-degree-of-freedom bluff body positioned in water is intensified by the positive excitation, which is affected by the upstream interfering body and also by the downstream obstacles. This paper investigates the effect of downstream interference on galloping piezoelectric energy harvester performance. A mathematical model of the piezoelectric energy harvester under disturbance is established based on the extended Hamilton’s principle, and the theoretical output is further derived. The accuracy of proposed model is verified by the results of circulating water channel experiment. The effect of interference shape and approximate spacing (L/D) on system output is further analyzed, and the results show that the harvester performance is substantially improved when the distance between the bluff body and downstream interference is sufficiently small, and the interference is an elliptical cylinder with an aspect ratio of 0.6, i.e., the output power is 0.624 mW, which is improved by 24.39 % when L/D=1.8 and U=0.5m/s. Precise numerical calculations are further utilized to indicate that the harvester’s output performance is optimal when the downstream interference angle is 30°.