Electromechanical charge pumps based on dielectric elastomer membranes: maximal energy of conversion for energy harvesting applications
Sprache des Vortragstitels:
SPIE 2011 Smart Structures/NDE
Sprache des Tagungstitel:
Dielectric elastomer generators promise exceptionally high values of
specific energy that can be electromechanically converted. In addition they are based on cheap and robust materials making them economically interesting candidates for energy harvesting applications on large and small scales.
Here we present an experimental demonstration of an electromechanical
charge pump operating between two charge reservoirs at different
electrical potentials. The mechanical energy is supplied with compressed air, resulting in an inflation of an elastomer membrane to a balloon shape. The charge pump is operated close to the limits of material failure in order to assess the maximal specific energy of conversion for the elastomer used, in our case the common 3M™VHB™4910 acrylic elastomer tape. These limits include the dielectric breakdown strength limiting the maximum useable electrical field, the stretch of rupture limiting the deformation and the borderline of the electromechanical pullin instability. The harvesting results are compared to a thermodynamic model of the system and different operating frequencies are reviewed with respect to electric losses to determine the ideal operating conditions
in future devices.
The experimental results accompanied by the theoretical analysis may
be used as a benchmark for the aptitude of the VHB elastomer tape in
specific energy harvesting applications. Our fully computer controlled, laboratory scale generator set-up may be readily used to test other elastomers with favorable properties, like elastomers with a large dielectric constant or elastomers with an exceptionally high dielectric strength, etc.