A miniaturized electromagnetic energy harvester with volt-level output based on stacked flexible coils

The bottleneck of the miniaturized electromagnetic vibration energy harvester (EVEH) device is the limited output voltage and power. Commonly reported mV-level AC output of the EVEHs cannot be rectified and used. In this work, we report a cost-effective EVEH device based on batch-fabricated flexible springs and coils. At an acceleration of ±1 g peak-to-peak amplitude (±9.8 m s^-2), a maximum output peak-to-peak voltage of 1.57 V and an output power of 91.8 μW are measured, at a frequency of 66 Hz. The output voltage of the EVEH is successfully rectified, amplified (passively) and used to charge a supercapacitor.