In recent years, attention has been paid to technology (energy harvesting) that extracts electric power from minute energy such as heat and light in the environment.Among them, the technology that extracts power from the kinetic energy of a vibrating object is called vibration power generation, and it is not affected by the weather.

　The research group has so far succeeded in generating power at the microwatt level from mechanical vibrations with a constant period, such as motors and washing machines, through efforts to develop vibration power generation elements using the piezoelectric effect.However, there is a problem that the generated power is greatly reduced by impulsive vibrations generated by human walking or the like.

　A theoretical analysis revealed that in the case of impulsive vibration, the amount of kinetic energy that can be stored in the power generation element is small, which is the cause of the drop in generated power.Therefore, we aimed to increase the amount of kinetic energy that can be received from impulsive vibration and use a mechanism that can accumulate it for a certain period of time.

　Therefore, we have developed a new one-yen coin-sized element that converts vibration energy into electric power by attaching a vibration amplifying part with a U-shaped structure to the vibration power generation element.As a result, we succeeded in increasing the power generation performance from impulsive vibration by about 1 times.

　The result of this research is that the power generation performance can be improved without increasing the area of ​​the element.It is expected to be applied to technology that generates power that can drive small wearable terminals such as smartphones and wireless earphones from non-stationary vibrations including walking motion.

Paper information:[Applied Physics Letters] Enhanced Performance on Piezoelectric MEMS Vibration Energy Harvester by Dynamic Magnifier under Impulsive Force