Study On Serpentine Piezoelectric Energy Harvester Based On Flexible Substrate

With the rapid development of micro/nano technology,more and more wearable devices and implantable medical electronic devices are widely used,which puts forward newrequirements for soft,light renewable power supply equipment.Traditional piezoelectric energy harvesters based on rigid substrates may no longer be suitable for new working environments,so flexible piezoelectric energy harvester with excellent flexibility,tensilebending and biocompatibility has become a hot research topic at present.In recent years,the research on the flexible piezoelectric energy harvester has focused on the selection ofpiezoelectric materials and the design of new structures to improve its output performance to meet the energy demand of various electronic products.An improvement of the existing PZT ribbon array structure is made in this paper,and the flexible serpentine piezoelectric energy harvester with two structures is designed by using the snake-shaped structure innovatively.The structure 1 improves the sensing ability of the PZT film to deform in different directions then improves the output performance of the device.At the same time,the mechanical and electrical characteristics of flexible piezoelectric harvesters are analyzed theoretically and a complete theoretical model is constructed.Finally,thesnake-shaped structure and theoretical model are verified by ABAQUS finite elementprogram,and the relative error between the theoretical calculation results and the simulation results is 5.15%.The fabrication of flexible piezoelectric energy harvester was completed by MEMS process,and the fabrication process details of PZT film and transfer printing process were studied and optimized.Finally,PZT film with good performance was prepared and thestructure 1 was successfully transferred from silicon substrate to flexible PI substrate.The XRD test shows that the PZT films prepared in this paper are mainly?110?orientation,and their selectivity orientation reaches 70.55%,the subsequent tests show that PZT films can obtain good dielectric and ferroelectric properties under?110?orientation.The leakage current test shows that the leakage current of the PZT film is controlled within 1.2×10^-8A at a loading voltage which of step length 0.1 V in the range 0-15 V.The dielectricproperties test shows that the capacitance amplitude does not exceed 3.1 at a loading voltage of 50-10000 Hz,amplitude of 1 V and the relative dielectric constant reaches 1062 at aloading voltage of 50 Hz.The ferroelectric property test shows that the hysteresis loop is well saturated and the Pr is 13.6,-Pr is 10.1.Through the output test of the device,the open-loop voltage of the flexible piezoelectric energy harvester prepared in this paper changesperiodically with time,and under the condition of buckling displacement load of 1.5 mm,the maximum voltage of structure 1 in direction 1 reaches 120.45 mV,the maximum voltage in direction 2 reaches 44.8 mV,which has certain practical application value.