Piezoelectric Energy Harvesting Devices Research Articles

Electromechanical Modeling of MEMS-Based Piezoelectric Energy Harvesting Devices for Applications in Domestic Washing Machines

Microelectromechanical system (MEMS)-based piezoelectric energy harvesting (PEH) devices can convert the mechanical vibrations of their surrounding environment into electrical energy for low-power sensors. This electrical energy is amplified when the operation resonant frequency of the PEH device matches with the vibration frequency of its surrounding environment. We present the electromechanical modeling of two MEMS-based PEH devices to transform the mechanical vibrations of domestic washing machines into electrical energy. These devices have resonant structures with a T shape, which are formed by an array of multilayer beams and a ultraviolet (UV)-resin seismic mass. The first layer is a substrate of polyethylene terephthalate (PET), the second and fourth layers are Al and Pt electrodes, and the third layer is piezoelectric material. Two different types of piezoelectric materials (ZnO and PZT-5A) are considered in the designs of PEH devices. The mechanical behavior of each PEH device is obtained using analytical models based on the Rayleigh–Ritz and Macaulay methods, as well as the Euler–Bernoulli beam theory. In addition, finite element method (FEM) models are developed to predict the electromechanical response of the PEH devices. The results of the mechanical behavior of these devices obtained with the analytical models agree well with those of the FEM models. The PEH devices of ZnO and PZT-5A can generate up to 1.97 and 1.35 µW with voltages of 545.32 and 45.10 mV, and load resistances of 151.12 and 1.5 kΩ, respectively. These PEH devices could supply power to internet of things (IoT) sensors of domestic washing machines.

Recent Developments and Prospects of M13- Bacteriophage Based Piezoelectric Energy Harvesting Devices.

Recently, biocompatible energy harvesting devices have received a great deal of attention for biomedical applications. Among various biomaterials, viruses are expected to be very promising biomaterials for the fabrication of functional devices due to their unique characteristics. While other natural biomaterials have limitations in mass-production, low piezoelectric properties, and surface modification, M13 bacteriophages (phages), which is one type of virus, are likely to overcome these issues with their mass-amplification, self-assembled structure, and genetic modification. Based on these advantages, many researchers have started to develop virus-based energy harvesting devices exhibiting superior properties to previous biomaterial-based devices. To enhance the power of these devices, researchers have tried to modify the surface properties of M13 phages, form biomimetic hierarchical structures, control the dipole alignments, and more. These methods for fabricating virus-based energy harvesting devices can form a powerful strategy to develop high-performance biocompatible energy devices for a wide range of practical applications in the future. In this review, we discuss all these issues in detail.

Analysis of Maximal Operation Amplitudes of Piezoelectric Vibration Energy Harvesters

The paper deals with an analysis of maximal operation amplitudes of piezoelectric energy harvesting systems generating electrical energy from ambient vibrations. Energy harvesting systems could be very interesting alternative for autonomous powering of ultra-low power electronics, sensors and wireless communication. A design of piezoelectric vibration energy harvester is based on the cantilever beam design with active piezoelectric layers. The output power is proportional to an amplitude of relative oscillation of this resonance mechanism. This paper presents an analysis based on the simulation model of multidisciplinary piezoelectric energy harvesting device, enabling an optimization of its key parameters ensuring a maximal efficiency of the system. Such analysis is also essential for development of new energy harvesting systems formed of new smart materials and structures which could be integrated in future development processes.

Kinetic Energy Harvesting for Wearable Medical Sensors.

The process of collecting low-level kinetic energy, which is present in all moving systems, by using energy harvesting principles, is of particular interest in wearable technology, especially in ultra-low power devices for medical applications. In fact, the replacement of batteries with innovative piezoelectric energy harvesting devices can result in mass and size reduction, favoring the miniaturization of wearable devices, as well as drastically increasing their autonomy. The aim of this work is to assess the power requirements of wearable sensors for medical applications, and address the intrinsic problem of piezoelectric kinetic energy harvesting devices that can be used to power them; namely, the narrow area of optimal operation around the eigenfrequencies of a specific device. This is achieved by using complex numerical models comprising modal, harmonic and transient analyses. In order to overcome the random nature of excitations generated by human motion, novel excitation modalities are investigated with the goal of increasing the specific power outputs. A solution embracing an optimized harvester geometry and relying on an excitation mechanism suitable for wearable medical sensors is hence proposed. The electrical circuitry required for efficient energy management is considered as well.

Design of a piezoelectric energy harvesting device based on ZnO–Na2Ti6O13 heterojunction nanogenerator

Enhancing the performance of nanogenerators is vital in the development of new piezoelectric applications that reveal high sensitivity to the surrounding waste of mechanical vibrational energy. In this paper, two major solutions are presented. The first is an easy and low-cost nanogenerator method utilizing Disodium Hexatitanate (Na2Ti6O13) as an alkali catalyzed material for growing the ZnO seed layer. The second solution is to suppress the screening effect that takes place in ZnO-metal harvester by forming a ZnO–Na2Ti6O13 heterojunction harvester. In other words, improvement can be realized by adopting a p-n junction approach instead of using the traditional Schottky contact approach. The ZnO–Na2Ti6O13 nanogenerator was grown hydrothermally. The size and nanofiber’s shape, material compounds distribution in the p-n junction and the crystal phases are investigated. The result was a fabricated ZnO nanofiber with a length and diameter of 3.726 μm and 0.158 μm respectively and the average crystal size of the Na2Ti6O13 nanofiber was 97.74 nm, with a fiber diameter of approximately 8.699 nm. The maximum AC voltage (Vpk-pk) and current upon finger pressing reached about 2 V and 2 μAcm−2 respectively. A good rectification property resulted based on the use of a p-n junction approach. The ZnO–NTO nanofiber could provide DC voltage up to 3.6 V where the derived energy is sufficient to power LCD digital screen.

Aging assessment of piezoelectric energy harvester using electrical loads

Vibrational energy harvesting is an alternative solution for replacing batteries in autonomous wireless devices. Besides the performance of piezoelectric energy harvesting generators, the reliability of such structures must be considered when long lifetime is required. In this paper, we propose a new approach based on stress electrically induced to deal with aging of piezoelectric bimorph structure for vibrational energy harvesting. To this end, induced mechanical stress in bimorph structure using electrical solicitation is investigated and compared with mechanical excitation by using finite element modelling. A dedicated test bench was developed. An accelerated aging test of a piezoelectric bimorph operated at 178.5Hz (9x resonance frequency in real use) under a maximum stress of 50MPa using stress electrically induced approach was performed during 4 months. The results are discussed and showed the feasibility of this electrical approach for reliability studies of piezoelectric energy harvesting devices.

Influence of design parameters on performance of piezoelectric MEMS energy harvesting

The influence of design parameters of piezoelectric thin films on the performance of vibration-type piezoelectric energy harvesting devices is investigated experimentally. The devices have four layers of Pb(Zr,Ti)O3 thin films on a silicon-based microfabricated structure to obtain high output power. The initial deformation and output power are measured. The results indicate that the initial shape due to residual stress can influence the mechanical quality factor and output power, particularly for the low-acceleration regime. In addition, the influence of the weight of the mass is investigated by changing the weight of the harvester. It is experimentally demonstrated that the power density and the generative power’s ratio to the theoretical limit can be improved by increasing the weight. A very large value of the normalized power density, 55.45 mW cm−3 G−2 (1 G = 9.8 m s−2), is obtained when a tungsten mass is attached to the microfabricated harvesting device.

Piezoelectric energy harvester utilizing mandibular deformation to power implantable biosystems: A feasibility study

This study explores the feasibility of energy harvesting from the deformation of a piezoelectric material attached on the human mandible to power an implantable medical device such as deep brain stimulator. A finite element (FE) model of the human mandible was developed and verified experimentally. A piezoelectric energy harvesting device was designed and fixed onto a synthetic mandible to compare its experimental power output to the simulation results. A novel mandibular loading apparatus was designed to imitate the forces exerted on a mandible during mastication in a lab environment. The peak-to-peak voltages from finite element analysis (FEA) and experiment were 1.7 and 1.0 V. Despite the discrepancy in magnitude, similar voltage waveforms were obtained. A method to maximize the electrical efficiency of the proposed harvesting device was discussed.

Reduced-order modeling with multiple scales of electromechanical systems for energy harvesting

New technologies that aim at powering wireless nodes by scavenging the energy from ambient vibrations can be a practical solution for some structural monitoring applications in the near future. In view of possible large-scale applications of piezoelectric energy harvesters, an accurate modeling of the interfaces in these devices is needed for more advanced and reliable simulations, since they might have large influence on functionality and performance of smart monitoring infrastructures. In this perspective, a novel multiscale and multiphysics hybrid approach is proposed to assess the dynamic response of piezoelectric energy harvesting devices. Within the framework of the presented approach, the FE2 method is employed to compute stress and strain levels at the microscale in the most critical interfaces. The displacement-load curve of the whole device (so-called capacity curve or pushover curve) is then obtained by means of the application of a suitable pattern of static forces. Finally, the parameters of a reduced-order model are calibrated on the basis of the nonlinear static analysis. This reduced-order model, in turn, is employed for the efficient dynamic analysis of the energy harvesting device.

Piezoelectric Energy Harvesting From Roadways Based on Pavement Compatible Package

Scavenging mechanical energy from the deformation of roadways using piezoelectric energy transformers has been intensively explored and exhibits a promising potential for engineering applications. We propose here a new packaging method that exploits MC nylon and epoxy resin as the main protective materials for the piezoelectric energy harvesting (PEH) device. Wheel tracking tests are performed, and an electromechanical model is developed to double evaluate the efficiency of the PEH device. Results indicate that reducing the embedded depth of the piezoelectric chips may enhance the output power of the PEH device. A simple scaling law is established to show that the normalized output power of the energy harvesting system relies on two combined parameters, i.e., the normalized electrical resistive load and normalized embedded depth. It suggests that the output power of the system may be maximized by properly selecting the geometrical, material, and circuit parameters in a combined manner. This strategy might also provide a useful guideline for optimization of piezoelectric energy harvesting system in practical roadway applications.

Scour Damage Detection and Structural Health Monitoring of a Laboratory-Scaled Bridge Using a Vibration Energy Harvesting Device.

A vibration-based bridge scour detection procedure using a cantilever-based piezoelectric energy harvesting device (EHD) is proposed here. This has an advantage over an accelerometer-based method in that potentially, the requirement for a power source can be negated with the only power requirement being the storage and/or transmission of the data. Ideally, this source of power could be fulfilled by the EHD itself, although much research is currently being done to explore this. The open-circuit EHD voltage is used here to detect bridge frequency shifts arising due to scour. Using one EHD attached to the central bridge pier, both scour at the pier of installation and scour at another bridge pier can be detected from the EHD voltage generated during the bridge free-vibration stage, while the harvester is attached to a healthy pier. The method would work best with an initial modal analysis of the bridge structure in order to identify frequencies that may be sensitive to scour. Frequency components corresponding to harmonic loading and electrical interference arising from experiments are removed using the filter bank property of singular spectrum analysis (SSA). These frequencies can then be monitored by using harvested voltage from the energy harvesting device and successfully utilised towards structural health monitoring of a model bridge affected by scour.

Body-Integrated Self-Powered System for Wearable and Implantable Applications.

The human body has an abundance of available energy from the mechanical movements of walking, jumping, and running. Many devices such as electromagnetic, piezoelectric, and triboelectric energy harvesting devices have been demonstrated to convert body mechanical energy into electricity, which can be used to power various wearable and implantable electronics. However, the complicated structure, high cost of production/maintenance, and limitation of wearing and implantation sites restrict the development and commercialization of the body energy harvesters. Here, we present a body-integrated self-powered system (BISS) that is a succinct, highly efficient, and cost-effective method to scavenge energy from human motions. The biomechanical energy of the moving human body can be harvested through a piece of electrode attached to skin. The basic principle of the BISS is inspired by the comprehensive effect of triboelectrification between soles and floor and electrification of the human body. We have proven the feasibility of powering electronics using the BISS in vitro and in vivo. Our investigation of the BISS exhibits an extraordinarily simple, economical, and applicable strategy to harvest energy from human body movements, which has great potential for practical applications of self-powered wearable and implantable electronics in the future.

Harmonic design of piezoelectric energy harvesting device coupled with electric circuit using topology optimization method

In this paper, a novel method based on topology optimization is proposed to design the piezoelectric energy harvester connected to the closed electric circuit. The objective function is defined as to maximize the energy conversion efficiency under harmonic dynamic loads. A finite element model which is coupled with piezoelectric-circuit is applied to analyze the piezoelectric energy harvesting systems. Combining the solid isotropic material with penalization (SIMP) method for piezoelectric, an design optimization method that optimizes the piezoelectric material layout was developed. Complex sensitivity analysis was derived and the density function of the SIMP method is updated using the sequence linear programming method. The validity of the proposed approach was demonstrated by numerical example of energy harvester design.

Design of a MEMS-Based Piezoelectric Vibration Energy Harvesting Device for Automotive Applications

The automotive industry requires new sensors to improve automotive performance,comfort and safety. These sensors will need the electrical power for their operation,which could be supplied by future MEMS energy harvesting devices. We present thedesign of a MEMS-based piezoelectric vibration energy harvesting (PVEH) device. Thedesign is formed of two cantilevers of trapezoidal shape (2500  1064  9 μm) that havetwo proof masses in their ends. The cantilevers and proof masses are designed of siliconwith a PZT-5H film, considering the PiezoMUMPs fabrication process of MEMSCAP. ThisPVEH device can generate voltage when its structure is deformed at resonance under avibration acceleration. Finite element method (FEM) models of the PVEH device are developedto predict its electrical and structural behavior at resonance under a vibrationacceleration of 12 m/s2. The proposed device has a resonant frequency of 207.8 Hz, amaximum deflection of 201 μm and a generated voltage of 61.5 mV with an electrical resistiveload of 10 kΩ. A PVEH devices array could be used to supply electrical power tosensors of modern and future automobiles.

Y3+ doped 0.64PMN-0.36PT ceramic for energy scavenging applications: Excellent piezo-/ferro-response with the investigations of true-remanent polarization and resistive leakage

In this work, the detailed ferroelectric properties of pure and yttrium doped 0.64 Pb(Mg1/3Nb2/3)O3-0.36PbTiO3 (Y-doped PMN-PT) ceramics including determination of true remanent polarization and study of resistive leakage were investigated. In dielectric study, the transition temperature (Tm) for the pure and Y-doped ceramic was found to be 205 °C and 165 °C, respectively. Displacement vs. Voltage (D-V) butterfly loops were traced from which a high value of the piezoelectric coefficient for Y-doped PMN-PT (d33 = 604 pm/V) was revealed which was fairly greater than the observed value for pure PMN-PT (d33 = 547 pm/V). The Y-doped PMN-PT ceramic displayed excellent saturated ferroelectric hysteresis loops with higher values of coercive field (Ec), spontaneous (Ps) and remanent (Pr) polarizations, and pyroelectric coefficient (p) compared to the pure PMN-PT ceramic. Also, the Y-doped PMN-PT ceramic displayed good fatigue resistant characteristic indicating its high ferroelectric quality. The relative values of true remanent polarization i.e. Ptr/Pr (in %) were found to be ∼82.86% and 89.60% for pure and Y-doped PMN-PT, respectively using the “Remanent Hysteresis” Task. Also, the resistive-leakage characteristic of both pure and doped ceramics was analyzed using Time-dependent compensated (TDC) hysteresis task. Finally, both pure and Y-doped PMN-PT ceramics have been used for building piezoelectric energy harvesting devices (PEHDs). The Y-doped PMN-PT ceramic based PEHD showed enhanced performance by generating an output voltage around 60 V under periodic mechanical tapping (∼2.0 kgf @ 5 hz) and thus finds application in powering various self-powered devices.

Piezoelectric wind energy harvesting device based on the inverted cantilever beam with leaf-inspired extensions

Inspired by the fluttering of leaves in wind, we propose a novel type of wind energy harvesting device composed of a piezoelectric bimorph beam and flexible extensions. Working principle and advantages of the proposed design are discussed with numerical simulations conducted to investigate the influence of extension shape upon the device performance. Fabricated prototypes are tested in a simple experiment setup to give a description of the actual device performance. Results show that the leaf-inspired sector-shaped flexible extension corresponds to a better device performance. The test for the dual attachment case of the flexible extensions shows unexpected results, showing that the interaction and collision between the two flexible extensions are to be further explored and optimized.

Multi-band piezoelectric vibration energy harvester for low-frequency applications

Piezoelectric Energy Harvester (PEH) is a promising technology for harvesting energy from low frequency ambient vibrations. To generate the power from these low-frequency signals, PEH device must adapt its attributes according to respective applied input frequency range or has a wide operational frequency band. This paper presents, an experimental study of PEH providing two different modes of operation. The first working mode is a result of beams resonant frequency which is auto-tunable due to moving Centre of Gravity (CoG). The second mode of operation is mainly due to cylinders rotational and vibration motion creating impact on beams surface as well as on walls of proof mass. The device provides dual band nature for applied frequency range. The maximum power transfer is studied by varying the resistive load experimentally and FEM simulation is also carried out for the same. First working mode provides frequency band of 21–35Hz generating average power (r.m.s.) of $$6\upmu \hbox {W}$$ with the optimal load of $$5\hbox {M}\Omega$$ . Second working mode has a frequency band of 45–60 Hz with an average harvested power (r.m.s.) of $$7.75\upmu \hbox {W}$$ with $$2\hbox {M}\Omega$$ optimal load. The maximum harvested output power (r.m.s.) is $$13.18\upmu \hbox {W}$$ . The effect of acceleration is studied for both working modes of the device. The frequency tuning range for the device is obtained as 46.96% for the provided band.

Design, Modeling, and Experiments of the Vortex‐Induced Vibration Piezoelectric Energy Harvester with Bionic Attachments

Since the energy demand increases, the sources of fluid energy such as wind energy and marine energy have attracted widespread attention, especially vortex‐induced vibrations excited by wind energy. It is well known that the lock‐in effect in vortex‐induced vibration can be applied to the piezoelectric energy harvester. Although numerous researches have been conducted on piezoelectric energy harvesting devices in recent years, a common problem of low bandwidth and harvesting efficiency still exists. In order to increase the response amplitude and decrease the threshold wind speed of vortex‐induced vibration, a bionic attachment structure is proposed based on the experimental method. In the present work, twelve models are designed according to the size of pits and hemispheric protrusions which are added to the surface of a flexible smooth cylinder. Compared with the smooth cylinder which is taken as a carrier, the harvester with the bionic structure shows stronger energy capture performance on the whole. As the threshold speed decelerates from 1.8m/s to 1 m/s, the bandwidth, on the contrary, increases from 39.3% to 51.4%. Particularly, for the 10 mm pits structure with 5 columns, its peak voltage can reach 47 V, and its peak power can reach 1.21 mW with a resistance of 800 kΩ, 0.57 mW higher than that of the smooth cylinder. Comparatively speaking, the hemispherical projections structure figures with a much more different energy capturing characteristic. Starting from the column, the measured voltage of the hemispherical bionic harvester is much smaller than that of the smooth cylinder, with a peak voltage less than 15 V and a reducing bandwidth. However, compared with the smooth cylinder, hemispheric projections with 3 columns have a better energy capture effect with a measured voltage of 35V, a resistance of 800kΩ, and a wind speed of 3.097 m/s. Besides, its output power also enhances from 0.48 to 0.56 mW.

Topology Optimization of the Thickness Profile of Bimorph Piezoelectric Energy Harvesting Devices

Due to developments in additive manufacturing, the production of piezoelectric materials with complex geometries is becoming viable and enabling the manufacturing of thicker harvesters. Therefore, in this study a piezoelectric harvesting device is modelled as a bimorph cantilever beam with a series connection and an intermediate metallic substrate using the plain strain hypothesis. On the other hand, the thickness of the harvester’s piezoelectric material is structurally optimized using a discrete topology optimization method. Moreover, different optimization parameters are varied to investigate the algorithm’s convergence. The results of the optimization are presented and analyzed to examine the influence of the harvester's geometry and its different substrate materials on the harvester’s energy conversion efficiency.

System reliability analysis of piezoelectric vibration energy harvesting considering multiple safety events under physical uncertainty

The most important duty of a piezoelectric vibration energy harvesting (PVEH) device is to reliably generate electric power as an output for sustainable operation of wireless sensor nodes, without experiencing mechanical failure. However, physical uncertainty, such as inherent variability in material properties and manufacturing tolerances, makes it difficult to guarantee satisfactory performance of the required functions of a PVEH device. Reliability analysis has been widely recognized as of great importance to evaluate system performance, while accounting for physical uncertainty. There have been a few prior attempts to delve into reliability analysis for the design of PVEH devices; these prior efforts were limited to calculating the probability of component success. However, PVEH devices need system reliability analysis that examines multiple performance functions, with the aim of calculating the probability of overall system success. The objective of this study is thus to present a systematic methodology for system reliability analysis of multiple safety events of a PVEH device under physical uncertainty. In this research, after deriving the electroelastically-coupled analytical model, the limit state functions of a PVEH device are derived under multiple safety events including: (1) resistance against fatigue failure; and (2) fulfillment of the target output electrical performances. Finally, system reliability analysis is performed by using the complementary intersection method. This study can provide insightful guidelines for designing a PVEH device under physical uncertainty.