Nonlinear piezoelectric vibration energy harvesting (VEH) offers distinct advantages over conventional linear harvesters, particularly in addressing the narrowband limitation inherent in resonance-based systems. By intentionally introducing nonlinear mechanisms, these devices can achieve improved energy conversion efficiency, broader operational bandwidth, and greater adaptability to environmental variability. Among nonlinear approaches, stopper-based configurations—also referred to as motion limiters—provide a practical method to generate piecewise nonlinear stiffness. In theory, properly designed stoppers induce hardening effects, suppress excessive displacements, and enable energy harvesting across multiple frequency bands. However, practical realization remains challenging, as stopper dynamics themselves may contribute unintended resonances and energy exchanges not accounted for in simplified models.