Charge Redistribution in Flextensional Piezoelectric Energy Harvesters

Abstract

Harvesting ambient wasted energy has been in recent years a prominent research endeavor, aimed at providing alternative energy sources for low-power electronic mobile devices. Among various solutions, piezoelectric energy harvesters have attracted major attention due to the scalability, high-efficiency and the universal presence of vibration sources. In this paper, we studied the charge redistribution phenomenon in piezoelectric energy harvesters employing flextensional structures numerically and experimentally. A finite element model was developed firstly to study the mechanical and electrical response of flextensional transducers. The simulation results were then validated by a corresponding experiment. The research reveals that energy is dissipated in the process that charge flows from the high potential region to the low potential region. The electrode shape has a significant effect on the efficiency, and therefore should be considered fully when designing new energy harvesters. This study also assists in the design of flextensional sensors and actuators.