Structure Optimization of Electret-based Electrostatic Energy Harvester

Abstract:

A variable capacitor based electrostatic energy harvester including a high elastic electret film was designed. The effects of structure parameters on the output power of the capacitor were studied by finite element method (FEM) and the structure of the capacitor was optimized. The experimental data are in agreement with the FEM calculations. The resonance frequency and output power can be adjusted by pre-stretching electret film and varying seismic mass. For an energy harvester, consisting of a fluorinated polyethylene propylene (FEP) electret film with an active area of 3 cm² and a surface charge density of 0.6 mC·m^-2, a V-shaped counter electrode with a depth of 4.0 mm, and a seismic mass of 0.06 g, an output power of 870 μW was achieved at its resonance frequency of 20 Hz and sinusoidal acceleration excitation of 1g.