Preparation and performance research of stacked piezoelectric energy-harvesting units for pavements

Abstract

The exploration and research of pavement piezoelectric energy harvesting technology provides new ideas for the collection and application of road green energy. To improve the applicability of the piezoelectric energy-harvesting units in road environment effectively, based on technical requirements of energy-harvesting units for pavements, this paper compares two processes for preparing stacked piezoelectric energy-harvesting units and evaluates their application performance in terms of electromechanical conversion performance and structural strength; and the optimal preparation process for the units is determined as well. Two detailed structure optimization schemes of U-shaped interlayer copper foil electrode structure and lateral lead electrode structure are designed, which are tested and evaluated from the three perspectives of energy output performance, working durability and material properties, and the optimal electrode structure is determined. The results indicate that at 0.7 MPa–10 Hz, the parallel connected units prepared based on the multilayer adhesive process can increase the terminal voltage by 28.0 V and the output power by 22.80 mW, which are superior than units prepared by the monolithic co-firing process. In addition, the multilayer units exhibit good structural stability and weatherability. Under the same load condition, the optimal load resistances of the units with the U-shaped interlayer copper foil electrode and the lateral lead electrode can reach 20 kΩ with comparable energy outputs. Subsequently, mechanical testing is conducted after 50,000 simulation (MTS) cyclic loading, the structural performance of the U-shaped interlayer copper foil units is relatively durable and stable: the open-circuit voltage is attenuated by 4.4 V, the output power is attenuated by 3.30 mW, and the average capacitance of a single unit is only attenuated by 3.4 nF. Finally, future research plan is discussed.