Airflow energy harvester of piezoelectric thin-film bimorph using self-excited vibration

Abstract

The airflow energy harvesters (AFEHs) of piezoelectric Pb(Zr,Ti)O3 (PZT) thin films were developed. Electric power was generated by self-excited vibration of the piezoelectric bimorph cantilevers induced by a continuous airflow. To enhance the vibration in low wind speed, we used very thin stainless-steel (SS) foils with thickness of 20μm as base substrates, and the PZT thin films were deposited on both surface of SS foils by radio-frequency (rf) magnetron sputtering. When the angle of attack (AOA) was 20° and above, stable self-excited vibration was generated at wind speeds larger than 4.5m/s. When the wind speed was 8m/s, the maximum output power reached 36.4μW at the AOA of 20°. From the evaluation of the thickness effect of the base cantilevers, it was confirmed that the thinner substrate reduced not only cut-in wind speed but also maximum output voltage.