Output Performance of a Road Energy Harvester Based on Piezoelectric Ceramic Recycling Technology

Watt-level road-vibration energy acquisition technology has wide application prospects because it can supply power to wireless low-power traffic-infrastructure sensors and solve power supply, wiring, and transmission difficulties. However, the depolarization and fragmentation of piezoelectric ceramics under long-term traffic loads leads to a significant decrease in their energy conversion efficiency. Hence, in this study, the PZT-5H piezoelectric ceramics used in road piezoelectric energy harvesters were recycled. An entire process was proposed for recycling piezoelectric ceramics. The experimental results show that the piezoelectric ceramics before and after recycling had a stable phase structure and excellent performance parameters. Under identical polarization conditions, the piezoelectric charge constant d(33) of the recycled ceramics reached 75% of that of the initial ceramics. Subsequently, the output performance of the piezoelectric harvester unit was tested under different traffic loads. When the excitation displacement was 1 mm and the excitation frequency was 10 Hz, the maximum open-circuit voltage of the proposed piezoelectric harvester unit was 21.08 V, close to the 23.13 V of the initial ceramic harvester; furthermore, the power generation performance recovery reached 91.14%. In this study, a technological process for recycling piezoelectric ceramics in a piezoelectric road energy harvester was proposed to offer new ideas for the industrialization of piezoelectric road backends.