Improvement of MCFC Stack Technology for Portable Use

摘要

Recently, portable terminal equipment such as notebook personal computers and mobile phones etc. have spread dramatically, and users are desirous of using portable terminal equipment and the like for office use. In particular, portable terminal equipment cannot even be charged for lack of commercial power sources on the sea, in mountains and at disaster sites, etc. Hydrogen cylinders comprising Proton Electrolyte Fuel Cells (PEFC) fuel are not obtainable anywhere. Although PEFC has been developed to satisfy such demands, because reliability and durability are low, these are not useful as the power supply source for portable devices. On the other hand, Molten Carbonate Fuel Cells (MCFC) is known for its long-term operation and stability. Because MCFC can use readily obtainable butane gas cylinders as fuel, MCFC is the best for portable power supply. However, because MCFC has been developed for large-scale use, the cell components and the stack technology should be optimized for downsizing. Therefore, it is intended to solve problems associated with developing a portable MCFC. This paper examines the following three points: (1) the optimization of the electrolyte impregnation method, (2) the optimization of the electrolyte sheet method and (3) the optimization of the manifold sealing method. As a result, stack twisting can be controlled by a twist prevention jig at the time of electrolyte pre-impregnation. The manifold sealing method can solve this by using an electrolyte sheet and a matrix sheet as the sealing component. Oxidation of the catalyst can be prevented by improving the electrolyte impregnation procedure, with the same Direct Internal Reforming Molten Carbonate Fuel Cells (DIR-MCFC) performance as with a conventional MCFC. Although the highest filler content of the electrolyte to the anode electrode is 97%, in a cathode electrode it is 129% if the cathode electrode was pre-oxidized at 500°C. Further improvement is necessary for the electrolyte pre-impregnation method, which cannot be applied to the Li/Na electrolyte in that the electrolyte cannot be sufficiently filled into both electrodes.