Optimal electrode coverage based on a new criterion for piezoelectric energy harvesters

in Energy Conversion and Management (2023), 284

Piezoelectric energy harvesters (PEHs) are a promising alternative to conventional electrochemical batteries with the advantage of being self-powered and maintenance-free, but their application is ... [more ▼]

Piezoelectric energy harvesters (PEHs) are a promising alternative to conventional electrochemical batteries with the advantage of being self-powered and maintenance-free, but their application is severely restricted by the low electric power output. It has been reported that the power output of PEHs can be enhanced by well-designed electrode coverage. A common design criterion for beam-like PEHs is based on the strain node to avoid electrode charge cancellation. This criterion, however, is not feasible for PEHs subject to complex spatio-temporal excitation patterns, where strain nodes change their position. This work proposes a new design criterion for optimal electrode coverage of beam-like PEHs based on the closed-form solution of the circuit equation that expresses voltage as a function of the beam’s dynamic response, specifically the cross-section rotation. The new criterion maximizes the averaged curvature of the beam segment covered by the electrode using data on the instantaneous rotation field. The improved physical significance and reliability of the presented criterion are discussed. The associated electrode optimization procedure is then exemplified for PEHs driven by fluid flow, which helps to realize a complex excitation pattern. Two numerical studies, both including a variety of combinations of fluid densities and inlet velocities, are performed to demonstrate that an optimal electrode configuration can be obtained with the proposed criterion. Comparison of different electrode configurations in above studies finally leads to useful conclusions on the power output and electrode configuration. [less ▲]

Presentation in Computational Sciences PhD Presentation Day

Presentation (2022, March 22)

Multiphysics Modelling of Flow-Driven Piezoelectric Energy Harvesters

Poster (2021, May 21)

Toward fluid-structure-piezoelectric simulations applied to flow-induced energy harvesters

Poster (2019, November 15)

The subject deals with the simulation of flow-induced energy harvesters. We focus in particular on the modelling of autonomous piezo-ceramic power generators to convert ambient fluid-flow energy into ... [more ▼]

The subject deals with the simulation of flow-induced energy harvesters. We focus in particular on the modelling of autonomous piezo-ceramic power generators to convert ambient fluid-flow energy into electrical energy. The vibrations of an immersed electromechanical structure with large amplitude have to be taken into account in that case. One challenge consists in modelling and predicting the nonlinear coupled dynamic behaviour for the improved design of such devices. The set of governing equations is expressed in integral form, using the method of weighted residuals, and discretized with finite elements using the open source package FEniCS. Preliminary results of separated problems using FEniCS will be detailed and discussed (e.g. Navier-Stokes with or without moving meshes, nonlinear elasticity, aeroelasticity and electromechanical coupling). The objective is to validate each problem independently before coupling all the phenomena in a monolithic framework. Those simulations involve nonlinearities at many levels of modeling. The perspective of using reduced order models to limit the computational cost (in time and memory) will be discussed in an outlook to this work. [less ▲]