Optimized testing of package for stacked piezoelectric energy harvester in roadway applications

Piezoelectric energy harvester (PEH) applied in collection and conversion of mechanical energy on roadway has attracted widely attentions in recent years. This study aims to improve a new type of road-compatible stacked PEH (sPEH), which consists of six PZT stacked piezoelectric transducers connected in parallel and a matched package to better the output efficiency and working life of sPEH. Uniaxial compression tests are conducted to measure the output power, voltage and current of the sPEH. The package of the sPEH is optimized depending on the sensitivity of the output to loading amplitude, frequency, package material and cover thicknesses. Tests results show that the output of the sPEH increases as increasing load amplitude and frequency. The sPEH with a package being polyethylene and 3 mm thick exhibited up to maximum output of 21.97 mA power and 8.59 W/m2 power density which successfully charges a lithium battery in 24 h. Finally, the protection of package against the erosion of environment and crushing of traffic load in road application was verified by immersion and compression test.