| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2005: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2004: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
We propose a new direct methanol fuel cell by a membrane electrode assembly spiraled or zigzag folded down. This fuel cell is formed by a membrane, which is made up of anode and cathode electrodes on a spiraled sheet or a zigzag-folded sheet, separated by insulation films and current collectors. Individual anodes, cathodes and membranes form a unit cell, which is connected to the adjacent unit cell. The fuel cell is respected to achieve high output voltage through easy in-series connection. Since it is not necessary to connect electrodes, as in the manner of conventional bipolar plates, there is no increase in fabrication cost and no degradation in reliability. The fuel feeds for the anode and cathode are achieved through fuel feed material and space on each insulation films, which do not require electricity to run a pump or blower.
The experimental cells were formed with an active area of 16cm^2×2 on membrane folded cells. Nafion117 was used as the membrane. Electrochemical catalysts for the anode of the DMFC were produced from platinum and ruthenium, and electrochemical catalysts for the cathode of the DMFC were made from platinum. Filter papers with ten incisions were inserted between anodes to improve their methanol supply. A three-cell DMFC was constructed using the proposed zigzag-folded membrane electrode assembly in order to obtain high output voltage. The three-cell assembly had six electrodes on the membrane, and the areas of the electrodes and the membrane were 16 cm^2 and 150cm^2, respectively. Titanium mesh was used as the current collector. Insulation films having slits and a thickness of 3.6mm were inserted between cathodes to feed air and to insulate adjacent cells. An open-circuit voltage of 1.7V was obtained at the current density of 0.1mA・cm^<-2>, which is three times larger than that for a single cell. Moreover, in experimental zigzag three-cells, portable cassette player operated.
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