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Energy Harvesting with a Bimorph Type Piezoelectric Diaphragm Multilayer Structure and Mechanically Induced Pre‐stress
Author(s) -
Lein Mikko,
Juuti Jari,
Jantunen Heli,
Palosaari Jaakko
Publication year - 2016
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201500429
Subject(s) - bimorph , piezoelectricity , energy harvesting , materials science , voltage , diaphragm (acoustics) , stress (linguistics) , power density , power (physics) , mechanical energy , compression (physics) , acoustics , electrical engineering , composite material , engineering , vibration , physics , linguistics , philosophy , quantum mechanics
The energy harvester is constructed from four circular bimorph type piezoelectric diaphragms which are stacked and pre‐stressed with a mechanical spring. Mechanical pre‐stress keeps the voltage cancellation at a minimum between the bimorph layers and enhances the physical compression distance. This results in much higher power densities than previously reported for low‐frequency piezoelectric energy harvesting applications. The voltage output at ∼1 Hz compression frequency, which closely corresponds to the pace of human walking, gives an average power output of 11.30 mW, a very high average power density of 10.55 mW cm −3 for the piezoelectric material. The results show that bimorph type stacked and pre‐stressed piezoelectric diaphragms can provide a sufficiently compact and efficient structure to harvest useful amounts of energy; enough, for example, to power and recharge various portable devices and sensors in future applications.