Watt-level road-compatible piezoelectric energy harvester for LED-induced lamp system

Abstract Road-compatible piezoelectric energy harvesters (RPEHs) have recently been widely demonstrated to power traffic ancillary facilities and intelligent sensing devices. The output power of RPEHs was previously always at the μW or mW level. A watt-level RPEH (π × 17.52 × 8 cm3), consisting of 40 metal–piezoelectric ceramic units, based on an improved drum-transducer structure is proposed herein. Its electrical productivity under different excitation frequencies and displacements was tested in a laboratory. At a 10 Hz excitation frequency and 2 mm excitation displacement, a maximum output voltage of 25.64 V, maximum output current of 25.64 mA, and maximum output power of 657.41 mW (power density: 6.83 W/m2) were observed at a 0.9 kΩ load resistance. Then, its electrical productivity at different vehicle speeds was tested on an actual roadway. When a small-sized vehicle passed the RPEH at a speed of 80 km/h, a maximum output voltage of 40.39 V, maximum output current of 403.9 mA, and maximum output power of 16.31 W (power density: 169.52 W/m2) were observed at a 0.1 kΩ load resistance. This is the maximum output power observed thus far on an actual roadway. The RPEH successfully illuminated a 5-m-long LED-induced 300-lamp strip, demonstrating potential for car networking and intelligent transportation.