Piezoelectric and Electrostatic Bimetal-Based Thermal Energy Harvesters

International audienceThis paper reports on innovative thermal energy harvesters (TEH) turning heat fluxes into electricity in a two-step conversion, involving (i) a curved bimetallic strip converting thermal gradients into mechanical oscillations, which are then (ii) converted into electricity by a piezoelectric or an electret-based electrostatic transducer. This work mainly focuses on (i) the optimizations of the piezoelectric devices, (ii) a first demonstration of a Wireless Sensor Node powered by our electrostatic transducers, validating the viability of bimetal-based thermal energy harvesters, and (iii) the possibility of future scaled scavengers by a micrometric silicon approach to improve efficiencies and power densities