Energy harvesting from biting force with thin sheet harvester based on electret and dielectric elastomer

Mouthguard-type sensors have been developed to monitor oral health. These sensors are expected to be used in preventive medicine; however, long-term monitoring has not been realized owing to problems with their power supply. In this study, a thin-sheet energy harvester was developed to generate a biting force. The proposed harvester consists of an electret and a dielectric elastomer, which are embedded inside a double-layered mouthguard and integrated with a mouthguard-type sensor. By utilizing a large deformation of the dielectric elastomer owing to the biting force, the proposed harvester can generate high output power even from low frequency movements such as the biting force. The design was optimized based on the analysis of equivalent circuit of the proposed harvester. The fabricated mouthguard harvester produced 2.5 mu W under the load equivalent to the biting force, which was 560 times higher than that by piezoelectric elements under the same condition. Further experiments on power charging and feeding demonstrated that the fabricated mouthguard harvester generates sufficient power to transmit the data measured by the mouthguard sensor every 5 min. These results demonstrate that the proposed principle is effective as a power-generation method for low-frequency movements in a narrow space.

Automated summary

This study presents the development of a thin-sheet energy harvester for monitoring oral health. By utilizing the biting force and the large deformation of the dielectric elastomer, the harvester can generate high output power from low frequency movements. The experimental results show that this principle is an effective power-generation method for low-frequency movements in a narrow space.