Energy scavenging from vibration with two-layer laminated fluoroethylenepropylene piezoelectret films

Abstract

Fluoroethylenepropylene (FEP) piezoelectret films with a cross-tunnel structure were prepared using a templatebased process and contact charging. Energy harvesting from the fabricated FEP films was investigated in the {3-3} mode at various seismic masses, load resistances and exciting frequencies.The results show that the output power is dependent on the seismic mass, load resistance and vibration frequency. Around the optimum load resistance, a normalized output power of 73 μW at 130 Hz was obtained for an FEP piezolectret film with a seismic mass of 60 g and an area of 7.1 cm 2 . At a vibration frequency of 150 Hz, the output power from an FEP film sample with an excited area of 3.1 cm 2 and a seismic mass of 54 g, is high enough to light a blue color LED diode, showing such thin, light and flexible FEP piezoelectret films may be applied in environmental vibration energy harvesters for powering lowpower electronic devices.

Fabrication process for FEP piezoelectrets based on photolithographically structured thermoforming templates

“…This corresponds to a piezoelectric d 33coefficent of 15,497 pC/N. Such a nonlinearity of d 33coefficient is often observed in piezoelectrets (Zhang et al 2015).…”

“…Over the last decade, the performance of fluorocarbonbased piezoelectrets, with respect to their piezoelectric coefficient, have shown a tremendous increase with values of up to several thousand pC/N (Zhang et al 2014) (Emmerich and Thielemann 2018;Zhang et al 2015Zhang et al , 2013Zhang et al , 2012. These piezoelectrets are usually based on polytetrafluoroethylene (PTFE) or fluoroethylenepropylene (FEP).…”

“…With the goal to increase the generated energy and usability, various studies address the production process and the performance of these piezoelectret-based harvesters. For different designs, they show promising results in d 33 -mode (Zhang et al 2015) as well as in d 31 -mode (charge generated perpendicular to direction of pressure) (Zhang et al 2016a). Piezoelectrets store, after charging, a quasi-permanent electric charge with a slow decay in the range of months and years.…”

Ferroelectret materials and devices for energy harvesting applications

“…13(B) [3]. Comparable values of d33 ~ 1000 pC/N were found in their research focusing on using different types of templates for pore production [6,72].…”

“…72,73] used a patterning and fusion bonding processes to stack two commercial fluoroethylenepropylene (FEP) films, of 12.5 µm thickness, together to form a crosstunnel structure, as shown in Fig. 10(D).…”