Aging assessment of piezoelectric energy harvester using electrical loads

Abstract

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.