Increased energy conversion efficiency in footstep energy harvesting pavements via a novel combination strategy

For an array composed of multiple footstep energy harvesting pavements (FEHPs), a critical challenge that limits large-scale application is the energy loss with reliability degradation caused by the combination of multiple harvesters under normal footstep displacement. To eliminate this problem, a novel combination strategy was proposed in this work to autonomously route current around inactive harvesters. Concurrently, a mechanical switching system free from external power supply was manufactured to serve as the actuator of proposed strategy. Furthermore, an accurate mathematical model was established for the array implementing the proposed strategy. The strategy demonstrates a strong universality, being applicable to any FEHP that exchanges power through displacement, as the displacement is set to a pedestrian-friendly 5 mm in this work. The combination strategy not only enables the FEHP array to reach higher energy conversion efficiency but also ensures the smooth delivery of electrical energy generated by multiple FEHPs working simultaneously. In experimental verification, a single action on one switching module within the array achieved a 33.3% output voltage increase compared to the conventional series-connection method under given conditions. For an array consisting of three FEHPs in demonstration test, the new strategy facilitates threshold voltage breakthrough under given conditions, yielding a peak DC output of 20 V for a resistor box and a stable power supply duration of 22 s for a thermo-hygrometer. These results validate the effectiveness of the proposed device and the superiority of the combination strategy, highlighting their application value and market potential in energy harvesting.