Design of high mechanical-electrical performance piezoelectric energy harvester for road applications: Modeling, theory, and experiment

The application of renewable energy contributes to the sustainable development of road infrastructure. Aiming at the inadequate mechanical-electrical performance of the cantilever piezoelectric energy harvester (PEH) which can be used for road electrical facilities, the shape and size of the PEH are optimized under low-frequency roadway conditions. Firstly, models of the PEH with different shapes are constructed using different methods. Then, the electrical and mechanical properties of the PEH are investigated based on the finite element method, and the shape of the PEH is determined. Finally, the electrical theory of the triangular PEH is derived and modified, and its electrical output effect is verified by experimental testing. The results show that reducing the free-end-width and length or increasing the fixed-end-width could improve the electrical performance of the PEH, but reducing the length would significantly increase the maximum stress and reduce the uniformity of stress distribution. Comprehensive analysis of the electrical and mechanical performance recommend the use of the triangular PEH. Meanwhile, the modified electrical theory is in good agreement with finite element and test results, and a single PEH reach an output power of 15.76 mW. The results help to improve the mechanical-electrical performance of PEH, which can provide a basis for the design of self-powered road electrical facilities.