Piezoelectric transducers are devices that can convert mechanical energy into electrical energy through the piezoelectric effect. The piezoelectric effect is a property exhibited by certain materials (such as certain crystals and ceramics) where they generate an electric charge when subjected to mechanical stress or pressure. This phenomenon occurs due to the displacement of positive and negative charges within the material's crystal lattice.
In the context of energy harvesting, piezoelectric transducers are used to generate electricity from mechanical vibrations, deformations, or pressure changes in their environment. The basic process of electricity generation in piezoelectric transducers for energy harvesting can be described in the following steps:
Mechanical Stress: The piezoelectric transducer is mechanically stressed or subjected to vibrations. This stress can come from various sources, such as ambient vibrations, mechanical vibrations from machines or equipment, human motion, or even airflow.
Deformation of the Material: When the transducer is mechanically stressed, the piezoelectric material within it experiences deformation or displacement at a microscopic level. This deformation causes a shift in the positions of positive and negative charges within the crystal lattice of the material.
Separation of Charges: Due to the shifting of charges, an imbalance of electric charges occurs in the material, resulting in the accumulation of positive and negative charges on opposite faces of the piezoelectric material.
Generation of Electrical Potential: The separation of charges leads to the development of an electrical potential across the transducer's electrodes, creating an electrical voltage.
Electrical Energy Collection: The generated electrical energy can be harvested and collected using the transducer's electrodes. These electrodes are connected to an external circuit or energy storage device (such as a capacitor or a battery) to store and utilize the harvested electrical energy.
Continuous Process: As long as the mechanical stress or vibrations are applied to the piezoelectric transducer, the piezoelectric effect will continue to generate electrical energy.
Piezoelectric energy harvesting is commonly used in various applications where there are sources of mechanical vibrations or movements available. It is an efficient method for generating electricity in small-scale, low-power devices, such as wireless sensors, wearable electronics, and other low-energy electronics, where it can supplement or replace traditional battery power sources.