Energy harvester based on low cost piezoelectric membrane for road traffic application

Piezoelectric harvesters are environmentally sustainable alternative electrical production technologies aimed at supplying small autonomous devices. The particular application in roads has significant potential. However, there are discrepancies about the effectiveness of these harvesters, and their costs limit their market expansion abilities. In this context, a novel harvester approach is explored that includes low-cost membrane piezoelectric patches in modified cymbal devices. The main novelty of this approach is the inclusion of an inner contact column that punctually transmits the load of the caps of the cymbal to the centre of the membrane piezoelectric patch, maximising its deformation and energy production capabilities. Experimental tests on piezoelectric elements, harvesters and embedder harvesting units have been performed with numerical simulations to optimise the design of the harvester. The results indicate that the more punctual the inner contact column is, the more electrical energy is produced, reaching values ten times greater than those of the present cymbal configuration. Embedding the harvester into a flexible pavement and positioning it under a wheel track are beneficial aspects of the execution. Finally, the dependency on the wheel speed is confirmed with wheel-track tests on a representative pad of the system.