Multiple axes vibration energy harvester based on PTFE and metal balls

In this paper, a novel electrostatic vibration energy harvester based on PTFE electrets and metal ball cluster is presented, which is designed for multiple axes and wideband frequency vibration applications. The advancements of the energy harvester include: (1) converting both vertical and horizontal vibration energy into electric energy; (2) low and wide frequency response; (3) simple structure and fabrication processes. Experimental results show that the device produces more power in vertical than in horizontal direction. From 10Hz to 30Hz, there is no sharp drop of output power on the frequency response trace of the device. The maximum peak output power reaches 25μW with vibration condition of 5mm @ 30Hz. For a 0.5μF capacitance load, the maximum charging power is 6.5nW.