Recent Studies on Vibrational Energy Harvesting of PZT Materials

Abstract

Lead Zirconate Titanates (PZTs) are piezoelectric materials which produce electric charges on application of mechanical stress (direct effect) or undergo dimensional change when subjected to an electric field (converse effect). PZTs are most widely used as sensors and actuators for active vibration control of aero structures, structural health monitoring (SHM), precision opening and closing of valves, sonar transducer etc. In recent years, the direct piezoelectric effect has been used for vibration energy harvesting. For example, PZT discs embedded in a shoe produce electric charges during walking which are used for charging of mobiles. Similarly, PZT tiles laid down on roads produce electric energy due to movement of vehicles and the energy is used for lighting street lights. The energy generated using PZTs are in the range of mico to milli watts, suitable for powering low power electronic devices such as wireless sensor networks. At CSIR-NAL, PZT materials are prepared in-house and different types of devices eg. unimorphs, bimorphs and multi-layered (ML) stacks are fabricated. In recent years, the devices are used for energy harvesting studies at RWRDC, HAL, Bangalore. The output voltage obtained from PZT unimorphs (5V) was more compared to energy produced from bimorphs and ML stacks. Also, PZT unimorph with large surface area produce more output voltage.