Field experiments of watt-level piezoelectric energy harvester for different embedded depths

Abstract

Road piezoelectric energy-harvesting technology uses the positive piezoelectric effect to convert vibrational energy produced by vehicular load to electrical energy. Road piezoelectric energy harvesters (RPEHs) are the core elements behind this technology. A new disc-type metal–piezoelectric ceramic transducer structure was developed to promote road piezoelectric energy collection and increase power generation from RPEHs. Finite element analyses and field tests were then conducted. The experimental results show that the disc transducers have excellent road compatibility. The greater the embedded depth of the transducer, the smaller is the output power of the RPEH; hence, an embedded depth of 2 cm was selected as the optimal value for comprehensive durability and electrical performance. When a small car travelling at a speed of 60 km/h passed over the RPEH embedded at a depth of 2 cm, a maximum voltage of 62 V, maximum current of 62 mA, and maximum utput power of 3844 mW (power density: 43 W/m2) were observed. The influence of the vehicle weight on the RPEH output power decreased with increase in speed. Therefore, this study confirms that the new disc-type RPEH is less costly, has excellent power generation, and requires less piezoelectric transducer material.