Screen printed piezoelectric films for energy harvesting

Abstract

This paper describes the development of screen printed vibration energy harvesters developed at the University of Southampton. The mark 1 harvester developed very low levels of power (2 mW) due to the poor piezoelectric properties of the printed film. Properties were improved by blending particle sizes and optimising firing and poling conditions. The new piezoelectric paste was applied to harvesters developed for the EU funded project TRIADE. Power outputs have improved to 240 mW from an excitation vibration of 0?29g rms (g59?8 m s 22 ) at 67 Hz. Multilayer structures also demonstrate further improvements, and the harvester has been demonstrated powering an autonomous wireless sensor system for condition monitoring.

Virtual instrument to obtain electrical models of piezoelectric elements used in energy harvesting

“…In recent literature, piezoelectric harvesters based on vibrational mechanical stimuli [8] have improved materials and physical placement of the piezoelectric layers in order to increase the amount of generated power. If the mechanical input to the harvester is based on impacts, such as human walking, applications based on placing piezoelectric foils inside footwear are prevalent [9].…”

High performance PZT thick film actuators using in plane polarisation

“…1a). [4][5][6][7][8] Additional insulation layers allow for crossing of conductor paths. During excitation, the electrical field extends through the thickness of the film.…”

Piezoelectrics: pressing the point home

“…At the heart of the harvester is the ability of piezoelectric materials to transform movement into electrical energy, but it is the shaping and arrangement of the piezoelectric material within a device that is crucial to maximising the power that can be extracted using this technology. In these applications thick films are often more effective than bulk materials as they can be integrated with the surrounding device architecture while at the same time providing a device that is sufficiently flexible to allow it to couple with the ambient vibrating environment 10 . By depositing PZT films onto a variety of substrates many of the speakers demonstrated effective harvesting capability.…”

“…The effectiveness of a simple cantilever design can be enhanced through connecting multiple devices together, creating different shapes and constructing multilayer devices. 10 One of the continued challenges for such devices is that the maximum efficiencies are observed when they are operated at their resonant frequencies. Unfortunately in real life situations the most abundant vibrations are normally at low frequencies and spread across a wide frequency range.…”

“…By depositing PZT films onto a variety of substrates many of the speakers demonstrated effective harvesting capability. The effectiveness of a simple cantilever design can be enhanced through connecting multiple devices together, creating different shapes and constructing multilayer devices 10. One of the continued challenges for such devices is that the maximum efficiencies are observed when they are operated at their resonant frequencies.…”