二重エネルギーハーベスティングデバイスが将来のワイヤレス医療用インプラントに電力を供給する可能性(Dual-energy harvesting device could power future wireless medical implants)

Energy harvesting can provide continuous power required for operating biomedical, physical, and chemical devices. However, providing sufficient power for many applications utilizing only a single modality through energy harvesting is still challenging due to their restricted power density considering the source energy that is below human body safety limits. Here, for the first time a high-power density energy harvester using piezoelectric and magnetoelectric conversion is demonstrated operating within the human body safety limit. This dual harvester can harvest energy from different directions which makes it insensitive to the source orientation. Prototype design is demonstrated to harvest magnetic and ultrasound energy simultaneously from a single device traveling through liquid/tissue media generating ultra-high power of ~52.1 mW (power density of ~597 mW/cm3) across input of ~500 μT rms magnetic field and ~675 mW/cm2 ultrasound intensity that is below the safety limits prescribed by the IEEE and FDA. This represents ~225% improvement compared to individual magnetoelectric system utilizing single source under safety limit. The device can recharge a 3V lithium-ion battery with 1 mAh capacity at a rate of ~1.67 mC/s in porcine tissue. These findings suggest that the dual energy harvester based on magnetic field and ultrasound has the potential to power various electronic applications, such as implantable devices and embedded components.