High-Performance Piezoelectric Energy Harvesters and Their Applications

This paper presents a state-of-the-art review on a hot topic in the literature, i.e., vibration based energy harvesting techniques, including theory, modelling methods and the realizations of the piezoelectric, electromagnetic and electrostatic approaches. To minimize the requirement of external power source and maintenance for electric devices such as wireless sensor networks, the energy harvesting technique based on vibrations has been a dynamic field of studying interest over past years. One important limitation of existing energy harvesting techniques is that the power output performance is seriously subject to the resonant frequencies of ambient vibrations, which are often random and broadband. To solve this problem, researchers have concentrated on developing efficient energy harvesters by adopting new materials and optimising the harvesting devices. Particularly, among these approaches, different types of energy harvesters have been designed with consideration of nonlinear characteristics so that the frequency bandwidth for effective energy harvesting of energy harvesters can be broadened. This paper reviews three main and important vibration-to-electricity conversion mechanisms, their design theory or methods and potential applications in the literature. As one of important factors to estimate the power output performance, the energy conversion efficiency of different conversion mechanisms is also summarised. Finally, the challenging issues based on the existing methods and future requirement of energy harvesting are discussed.

A comprehensive review on vibration energy harvesting: Modelling and realization

The last decade has witnessed significant advances in energy harvesting technologies as a possible alternative to provide a continuous power supply for small, low-power devices in applications, such as wireless sensing, data transmission, actuation, and medical implants. Piezoelectric energy harvesting (PEH) has been a salient topic in the literature and has attracted widespread attention from researchers due to its advantages of simple architecture, high power density, and good scalability. This paper presents a comprehensive review on the state-of-the-art of piezoelectric energy harvesting. Various key aspects to improve the overall performance of a PEH device are discussed, including basic fundamentals and configurations, materials and fabrication, performance enhancement mechanisms, applications, and future outlooks.

A comprehensive review on piezoelectric energy harvesting technology: Materials, mechanisms, and applications

Energy harvesting technologies have been explored by researchers for more than two decades as an alternative to conventional power sources (e.g. batteries) for small-sized and low-power electronic devices. The limited life-time and necessity for periodic recharging or replacement of batteries has been a consistent issue in portable, remote, and implantable devices. Ambient energy can usually be found in the form of solar energy, thermal energy, and vibration energy. Amongst these energy sources, vibration energy presents a persistent presence in nature and manmade structures. Various materials and transduction mechanisms have the ability to convert vibratory energy to useful electrical energy, such as piezoelectric, electromagnetic, and electrostatic generators. Piezoelectric transducers, with their inherent electromechanical coupling and high power density compared to electromagnetic and electrostatic transducers, have been widely explored to generate power from vibration energy sources. A topical review of piezoelectric energy harvesting methods was carried out and published in this journal by the authors in 2007. Since 2007, countless researchers have introduced novel materials, transduction mechanisms, electrical circuits, and analytical models to improve various aspects of piezoelectric energy harvesting devices. Additionally, many researchers have also reported novel applications of piezoelectric energy harvesting technology in the past decade. While the body of literature in the field of piezoelectric energy harvesting has grown significantly since 2007, this paper presents an update to the authors' previous review paper by summarizing the notable developments in the field of piezoelectric energy harvesting through the past decade.

https://iopscience.iop.org/article/10.1088/1361-665X/ab36e4/pdf

A review of energy harvesting using piezoelectric materials: state-of-the-art a decade later (2008–2018)

A review of vibration-based MEMS piezoelectric energy harvesters

In this paper, we present the development of two piezoelectric MEMS generators, {3–1} mode and {3–3} mode, which have the ability to scavenge mechanical energy of ambient vibrations and transform it into useful electrical power. These two piezoelectric MEMS generators are of cantilever type made by a silicon process and which can transform mechanical energy into electrical energy through its piezoelectric PZT layers. We developed a PZT deposition machine which uses an aerosol deposition method to fabricate the high-quality PZT thin film efficiently. Our experimental results show that our {3–1} mode device possesses a maximum open circuit output voltage of 2.675 VP-P and a maximum output power of 2.765 µW with 1.792 VP-P output voltage excited at a resonant frequency of 255.9 Hz under a 2.5 g acceleration level. The {3–3} mode device possessed a maximum open circuit output voltage of 4.127 VP-P and a maximum output power of 1.288 µW with 2.292 VP-P output voltage at its resonant frequency of 214 Hz at a 2g acceleration. We also compared the output characteristics of both the {3–1} mode and the {3–3} mode piezoelectric MEMS generators which were both excited at a 2g acceleration level.

/pdf/piezoelectric-mems-generators-fabricated-with-an-aerosol-1jg5gjxjop.pdf

Piezoelectric MEMS generators fabricated with an aerosol deposition PZT thin film

This paper presents a series of processes for fabricating lead-zirconate-titanate (PZT) microstructures on a silicon substrate. An aerosol deposition method was used to deposit PZT thick film at room temperature. The low temperature deposition enabled a special lift-off process for patterning thick PZT films using a THB-151N photoresist. The milling rate of THB-151N by PZT particles was found to be the same as the PZT deposition rate of 5 μm h−1. Using this patterning technique, complex configurations of PZT microstructures have been demonstrated. Suspended multi-layer PZT microstructures have also been realized in this work.

https://iopscience.iop.org/article/10.1088/0960-1317/18/5/055034/pdf

The fabrication of silicon-based PZT microstructures using an aerosol deposition method

This paper presents an acoustic impedance matching model for the power transmission in human tissue. Utilizing the piezoelectric effect, the acoustic wave provides a feasible way to wirelessly charge the battery of the implanted biochip. A modified matching method from Desilets microwave transmission theory is derived to match the acoustic impedance between the piezo-transmitter/receiver and the human tissue. The lead-zirconate-titanate (PZT, 39.71MRayl) is used to be the material of transmitter/receiver. Based on the results of the modified matching model, the double impedance matching layers are constructed by the aluminum alloy 6061T6 with impedance 17.1MRayl and polymethylmethacrylate (PMMA) with 3.33MRayl. The maximum power gain is 5.55 dB in simulation and 3.13 dB in experiment result

Xuan-Yu Wang

Papers

Piezoelectric MEMS generators fabricated with an aerosol deposition PZT thin film

The fabrication of silicon-based PZT microstructures using an aerosol deposition method

Study on the acoustic impedance matching of human tissue for power transmitting/charging system of implanted biochip