Thin solid structures may have significant displacement and deformation under the excitation of the surrounding fluid flows. Energy harvesting devices can make use of such fluid-structure interaction (FSI) phenomenon. This work aims to develop a robust and efficient strongly coupled partitioned algorithm for the numerical simulation of transient fluid-structure-piezoelectric interaction (FSPEI). Within the proposed framework, the fluid flow is resolved using the lattice Boltzmann method (LBM), while the thin solid structure is modeled with a corotational finite element method (FEM). The electro-mechanical coupling is introduced through a piezoelectric patch model. The developed FSPEI coupling strategy is first validated against a set of academic benchmark test cases. In parallel, dedicated experimental investigations are conducted to validate the numerical approach and to provide further physical insights into the flow dynamics around thin structures equipped with piezoelectric patches. The proposed methodology offers a reliable numerical tool for the analysis and optimization of piezoelectric energy harvesting devices based on flow-induced vibrations.