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Charge redistribution in piezoelectric energy harvesters

Appl. Phys. Lett. 100, 073901 (2012); http://dx.doi.org/10.1063/1.3685701 (3 pages)
Mark Stewart, Paul M. Weaver, and Markys Cain
National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW, United Kingdom

Piezoelectric energy harvesting cantilevers provide a simple, compact low cost construction method for energy harvesting from vibrational sources. Beam theory predicts a linear distribution of strain along the length of the beam, but the conversion of this strain to electrical energy is dependent on the coverage of the beam with active material. In this paper, we demonstrate how re-distribution of charge within the piezoelectric leads to losses that can be as high as 25% of the potential generated power. Reducing the area coverage of the piezoelectric is shown to significantly improve cantilever power output, with the optimum coverage being 2/3.
http://apl.aip.org/resource/1/applab/v100/i7/p073901_s1 

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