Robust piezoelectric composites for energy harvesting in high-strain environments

High-strain environments, such as are found in automobile tires, provide deformation energy that can be harvested using piezoelectric materials, for instance, for powering electronics such as wireless sensors. Despite numerous efforts, none of the present devices easily satisfy the stringent operating and lifetime requirements for use inside a car tire, such as mechanical (accelerations of up to 3000 m/s ² ) and thermal requirements (temperatures of −40°C to 120°C), often leading to complex and costly solutions. Polymer–piezoelectric ceramic composite properties can be designed to fulfill the operating requirements. Furthermore, these materials are suitable for low-cost mass production and easy integration in the tire itself. Composite materials with increased output can be manufactured using the dielectrophoretic processing technique, which causes the alignment of the piezoelectric particles inside the polymer matrix, to obtain materials with adequate flexibility combined with a high energy density. In this study, we present the design, synthesis, and integration of novel composite material foils in automobile tires. The advantage of these dielectrophoretically structured composite materials is demonstrated and their output is compared to conventional piezoelectric composites. Furthermore, the charge signal output of a number of foil-based prototypes tested using an automobile tire test rig is evaluated and discussed with respect to energy harvesting performance.