Design optimization of vibration energy harvesters fabricated by lamination of thinned bulk-PZT on polymeric substrates

The design optimization through modeling of a thinned bulk-PZT-based vibration energy harvester on a flexible polymeric substrate is presented. We also propose a simple foil-level fabrication process for their realization, by thinning the PZT down to 50 μ m and laminating it via dry film photoresist onto a PET substrate at low temperature (<85 °C). Two models, based on analytical and finite element modeling (FEM) methods, were developed and experimentally validated. The first, referred to as the hybrid model , is based mainly on analytical equations with the introduction of a correction factor derived from FEM simulations. The second, referred to as the numerical model , is fully based on COMSOL simulations. Both models have exhibited a very good agreement with the measured output power and resonance frequency. After their validation, a geometrical optimization through a parametric study was performed for the length, width, and thicknesses of the different layers comprising the device. As a result, an output power of 6.7 μ W at 49.8 Hz and 0.1 g, a normalized power density (NPD) of 11 683 μ W g −2 cm −3 , and a figure of merit (FOM) of 227 μ W g −2 cm −3 were obtained for the optimized harvester.