WIMS2 Seminar/Webinar on MEMS Energy Harvesting

Energy harvesting is now attracting much attention targeting at their applications such as automotive sensors, implantable medical devices and network nodes for structural health monitoring. The final goal of the present study is to develop MEMS-based electrostatic energy harvester using polymer electrets.
So far, we develop a novel nano-cluster-enhanced polymer electret based on CYTOP and demonstrate extremely-high surface charge density above
2mC/m2, which is up to 5 times larger than that of conventional electret materials. The nano clusters are formed in the electret film by local phase
separation between the polymer matrix and the animonsilane additives. It is found that these nano clusters serve as the charge trapping site in the electret films. We also developed novel photoionization charge technologies with soft X-ray and vacuum UV for charging 3-D electret structures.
With the aid of the novel CYTOP electret and new charging technologies, we developed MEMS vibration energy harvester with a nonlinear parylene
spring, which allows low resonant frequency, wide frequency response, and large oscillation amplitude simultaneously. With a prototype generator,
the total power output of 6 µW has been obtained at an acceleration of 1.4G at a frequency of 40Hz. We have also developed an early prototype of
battery-less sensor network node with the MEMS energy harvester and accomplished intermittent wireless data transmission. Piezoelectric polymer
electret based on the trench-filled parylene technologies is also under development.
In this talk, recent advances of MEMS-based energy harvester are discussed, and our new approach toward higher power output of electret generator
is also given.
Yuji Suzuki received the B.S., M.S., and Dr.Eng. degrees in mechanical engineering from the University of Tokyo, Tokyo, Japan, in 1987, 1989, and 1993, respectively. After spending one year at the Nagoya Institute of Technology, Nagoya, Japan, as an Assistant Professor, he joined the Graduate School of Engineering, University of Tokyo. He is currently with the Department of Mechanical Engineering, University of Tokyo, as a Professor. He serves as a steering committee member of IEEE MEMS, Editorial Board Member of JMM, and Vice Chair of JSME Micro-Nano Science & Technology Divistion. He also served as a general co-chair of IEEE MEMS2010 (Hong Kong). His research interests include MEMS-based energy harvesting, micro energy conversion such as microscale combustion, and optimal design/control of micro heat and fluid flow.