Wearable piezoelectrets for energy harvesting using human body motionMittwoch (22.05.2019) 15:58 - 16:02 Uhr Bestandteil von:
With respect to the enhanced applications of wireless electronical systems within the scope of Internet of Things, batteries as power sources are often used. Due to their limited power and lifetime, batteries need to be replaced in regular terms and are inefficient from both economic and ecological point of view. As the sustainability requirements increase, the relevance of energy autonomous electronical systems becomes more important. Thus, conversion of electric energy from the energy dissipated in the systems environment (e.g. kinetic energy) – called energy harvesting – is one of the key challenges to be solved in order to increase the sustainability of electronical systems. In the last years, piezoelectric materials as PZT have been extensively employed as transducer elements for energy harvesting but they are restricted in application fields due to their high stiffness. Within the scope of this work, piezoelectric electrets (piezoelectrets) are investigated as electromechanical transducers. In particular, electric energy is harvested from human body motion to develop wearable and energy autonomous sensor systems. Such/These systems can be easily embedded in the every-day life and support the human-machine-interface efficiently, since human body signals and movements can be perceived and interpreted directly by networked machines around them. Piezoelectrets are promising transducer elements for integration in textiles due to their light weight and high flexibility. Moreover, the low-cost manufacturing of piezoelectrets prospects an advantage in industrial production. In this work, irradiation cross-linked polypropylene (IXPP) and parallel-tunnel fluoroethylenepropylene (FEP) are assessed as transducer elements for energy harvesting. Different energy harvester configurations based on the piezoelectric longitudinal and transversal effects are simulated and implemented in order to verify quasi-static and dynamic piezoelectric coefficients and to estimate the generated power output. The suitability of piezoelectrets as “textile powerplants” is investigated as proof of concept.