Polarization Effect of Road Piezoelectric Energy Harvester under On-Site Road Conditions

Abstract

Road piezoelectric energy harvesting based on the piezoelectric effect is a green energy utilization concept, which converts mechanical energy into electrical energy. Because of favorable properties such as low carbon significance, this technology caters to widespread applications. The major limitation of this concept is the fatigue degradation of piezoelectric transducers under long-term traffic loads, which subsequently reduces the energy conversion efficiency. Moreover replacing piezoelectric harvesters through road surface reconstruction will incur high costs and damage the integrity of road surface. With regard to the aforementioned factors, this study presents a polarization method for on-site road conditions from the perspective of the recovery and maximizing the piezoelectric energy harvester. First, the polarization of piezoelectric layer under simulated on-site road conditions was tested in a laboratory. The test results show that better transducer repolarization effect is observed when the polarization temperature is greater than 120 °C, the polarization time is less than 30 min, the polarization voltage is 2 kV/mm (greater than 1.2 kV/mm), and the d33 reaches 314 pC/N. Then, for an excitation frequency of 10 Hz and a test displacement of 1 mm, the piezoelectric harvester unit, which is based on the polarization method for on-site conditions, is used for piezoelectric performance test. The maximum output voltage of the polarized piezoelectric energy harvester is 10.47 V, which is 81.79% that of the initial polarization harvester in the indoor environment. The study proposes a polarization system under on-site conditions for road piezoelectric energy harvester and its equipment construction method, along with the future recycling processing applications after the road piezoelectric energy harvester reached the service life of the road.