In this chapter, micro fuel cells fabricated by microelectromechanical system (MEMS) technology and hybrid power sources based on a combination of fuel cells and capacitors are introduced. These systems are new systems toward miniaturization of power sources. Significant efforts in developing micro (sub-watt) and portable (1-20 W) direct methanol fuel cell (DMFC) systems are being made, including developments of small fuel cells, such as micro fuel cells fabricated with MEMS technology. MEMS technology based on the manufacturing technology of semiconductor devices is a powerful tool to realize small devices. Examples reported to realize the DMFC configuration by MEMS technology, the so-called micro direct methanol fuel cells (μDMFCs), are introduced in this chapter. The hybrid power supply system based on fuel cells is an attractive power source; the utilization of fuel cells with the assistance of capacitor has the merit of realizing the power supply having the features of both fuel cell and capacitor, that is, a high power density and a high power output. In order to construct the hybrid power supply system, simulation of power output from the power supply, by varying the properties of capacitor and fuel cell, would be the introductory research. Typical assessments are described in this chapter.
ASJC Scopus subject areas