Wearable inertial energy harvester with sputtered bimorph lead zirconate titanate (PZT) thin-film beams

Abstract

Energy harvesting from human motion addresses the growing need for self-powered wearable health monitoring systems which require 24/7 operation. Human motion is characterized by low and irregular frequencies, large amplitudes, and multi-axial motion, all of which limit the performance of conventional translational energy harvesters. An eccentric rotor-based rotational approach originally used in self-winding watches has been adopted to address the challenge. This paper presents a three-dimensional generalized rotational harvester model that considers both linear and rotational excitations. A hypothetical power upper bound for such architectures derived using this generalized model demonstrated the possibility for harvesting significantly more energy compared to existing devices. A wrist-worn piezoelectric rotational energy harvester was designed and fabricated attempting to narrow this gap between existing devices and the theoretical upper bound. The harvester utilizes sputtered bimorph PZT/nickel/PZT thinfilm beams to accommodate the need for both flexibility and high piezoelectric figure of merit in order to realize a multi-beam wearable harvester. The prototype was characterized using a benchtop swing arm setup to validate the system-level model, which provides many degrees of freedom for optimization.

Harvesting Energy from Planetary Gear Using Piezoelectric Material

“…The principle of rotational piezoelectric energy harvesting operation is based on the PZT plucking for excitation, which results in PZT bending, vibration, or pressing, and thus voltage is generated. Researchers have used different excitation elements in rotational piezoelectric energy harvestings, such as mass [28,31], magnetic [33][34][35] centrifugal force [36,37], gravitational force [38][39][40], and gear teeth force [41,42] or a compilation of these elements [26,43,44]. They have also applied these elements to widen the broadband range [14,45,46] or for frequency up-conversion [6,43,47] and rotational frequency, which is considered to be low in some cases compared to piezoelectric resonant frequency.…”

A Review of Piezoelectric Vibration Energy Harvesting with Magnetic Coupling Based on Different Structural Characteristics

“…The sealed casing ensures that there is no contact between the interior of the body and the pacemaker batteries or circuits. Human motions such as arm or leg movements and breathing provide a particular energy source to power wearable and implantable devices [ 221 , 222 ]. Izadgoshasb et al proposed an efficient piezoelectric harvester that extracted energy from human motions to replace a pacemaker battery [ 223 ] ( Figure 20 a).…”

A Piezo-Electromagnetic Coupling Multi-Directional Vibration Energy Harvester Based on Frequency Up-Conversion Technique

“…However, it is difficult for the battery of intelligent wearable devices to meet the requirements of its constantly improving functions and long-time standby [2,3]. With the development of ultra-low power technology and micro-electro-mechanical system (MEMS) technology, it is possible to harvest environmental energy to supply power for intelligent wearable devices [4][5][6]. At present, the energy that can be used in the environment includes solar energy, heat energy, vibration energy and so forth, and vibration energy widely exists in the human living environment [7][8][9].…”