Piezoelectric energy harvesting cantilevers provide a simple, compact low cost construction method for energy harvesting from vibrational sources. Beam theory predicts a linear distribution of strain along the length of the beam, but the conversion of this strain to electrical energy is dependent on the coverage of the beam with active material. In this paper, we demonstrate how re-distribution of charge within the piezoelectric leads to losses that can be as high as 25% of the potential generated power. Reducing the area coverage of the piezoelectric is shown to significantly improve cantilever power output, with the optimum coverage being two thirds.
The energy harvesting market was worth $605 million in 2010 but is predicted to reach $4.4 billion by the end of this decade. For the market to reach its true potential we need to develop the products that can guarantee a greater energy yield and drive industrial adoption of energy harvesting products