초록 ▼

Disclosed herein is an electrode substrate for fuel cells comprising two porous, carbonaceous layers, each having a number of elongated holes for feeding reactant gases into a fuel cell which are provided near the center of the thickness in said layer, and a gas impermeable, carbonaceous separator,

Disclosed herein is an electrode substrate for fuel cells comprising two porous, carbonaceous layers, each having a number of elongated holes for feeding reactant gases into a fuel cell which are provided near the center of the thickness in said layer, and a gas impermeable, carbonaceous separator, interposed between said layers and having a number of elongated holes for flowing coolant which are provided near the center of the thickness in the separator. The porous layer is either a uniformly porous, carbonaceous monolayer, or has a two-layer structure comprising a more porous layer, a less porous layer and elongated holes for feeding reactant gases provided between said more porous layer and said less porous layer, the less porous layer having a bulk density larger than that of the more porous layer. There are also provided according to the invention processes for preparing such an electrode substrate for fuel cells.

대표청구항 ▼

In a process for producing an electrode substrate for fuel cells comprising (1) two porous carbonaceous layers, each having a number of elongated holes for feeding reactant gases into a fuel cell which holes are defined near the center of the thickness thereof, and (2) a gas impermeable, carbonaceou

In a process for producing an electrode substrate for fuel cells comprising (1) two porous carbonaceous layers, each having a number of elongated holes for feeding reactant gases into a fuel cell which holes are defined near the center of the thickness thereof, and (2) a gas impermeable, carbonaceous separator interposed between said layers, which process comprises (1) supplying, into a mold having a proper configuration, (i) materials for porous layer each of which is a mixture comprising 10-50% by weight of a filler (A), 20-40% by weight of a binder (B) and 20-50% by weight of a pore regulator (C), (ii) a material for forming the elongated holes for feeding reactant gases and (iii) a material for the separator, (2) press molding the thus supplied materials at a temperature in the range of from 70°to 170°C. and a pressure in the range of from 5 to 100 kg/cm2 for a time period in the range of from 10 to 60 minutes, (3) postcuring the press molded materials at the molding temperature for at least 2 hours and (4) calcining the postcured materials under an inert atmosphere at a temperature in the range of from 800°to 3,000°C., the filler (A) being selected from the group consisting of short carbon fibers and carbon particles, the short carbon fiber having a diameter in the range of from 5 to 30 m0.02 to 2 mm, and a linear carbonizing shrinkage in the range of not more than 3.0% when calcined at 2,000°C., the binder (B) being selected from the group consisting of phenol resins, epoxy resins, petroleum and/or coal pitches and mixtures thereof, and having a carbonizing yield in the range of from 30 to 75% by weight, the pore regulator (C) comprising organic granules, 70% or more of which have a particle diameter in the range of from 30 to 300 m100°C., the polymer being selected from the group consisting of polyethylenes, polypropylenes, polystyrenes, polyvinyl alcohols and polyvinyl chlorides, having a carbonizing yield of 30% by weight or less and being (1) a textile fabric of the polymer comprising single strand or bundles of a number of strands which have been textured, the strand or the bundle having a diameter in the range of from 0.5 to 3.3 mm, the distance between two strands or bundles parallel to the gas flow direction being in the range of from 1.5 to 5 mm and the distance between two strands or bundles perpendicular to the gas flow direction being in the range of from 5 to 50 mm, or (2) a grating-like shaped article of the polymer prepared by extrusion molding of a melt of the polymer into a die or by press molding of pellets or powder of the polymer in a mold, the gratings having a diameter or equivalent diameter in the range of from 0.5 to 3.3 mm, the distance between two gratings parallel to the gas flow direction being in range of from 1.5 to 5 mm and the distance between two gratings perpendicular to the gas flow direction being in the range of from 5 to 50 mm, the materials for forming elongated holes for feeding reactant gases being each supplied into the mold so that the elongated holes for feeding reactant gases are parallel to each other and to the electrode surface and one side surface of the electrode, are continuously elongated in the porous layer from one of the other side surfaces to another surface opposite thereto, and the elongated holes in the porous layer on one side of the separator and those in the porous layer on the other side of the separator have the directions perpendicular to one another, wherein the improvements comprise the process comprising the steps of: (a) supplying, into the mold having a proper configuration, the material for separator, the material for forming elongated holes for flowing coolant which material is a polymer, and the material for separator, in this order and press molding, or further, after press molding, postcuring and calcining, the material for separator comprising (i) 50-90% by weight of a filler of carbon particles having a diameter of 50 m10-50% by weight of a thermosetting resin binder; and (b) supplying, into the mold having a proper configuration, the material for porous layer, the material for forming elongated holes for feeding reactant gases, the material for porous layer, the shaped separator by press molding or the calcined separator prepared in the step (a), the material for porous layer, the material for forming elongated holes for feeding reactant gases, and the material for porous layer, in this order, press molding, postcuring, and calcining the postcured materials to integrate the materials as a whole body to obtain an electrode substrate provided with an intercooler, where (1) said separator has a number of elongated holes for flowing coolant which are constructed from said separator and provided near the center of the thickness in the separator, and which holes are parallel to each other and to the electrode surface and one side surface of the electrode, are continuously elongated in the separator from one of the side surfaces to another side surface opposite thereto, and have a diameter or equivalent diameter in the range of from 2 to 10 mm, and (2) said separator excluding the elongated holes for flowing coolant has an average bulk density of 1.2 g/cm3 or more, a specific gas permeability of 1×1031 4 cm2/hr.mmAq. or less, a thermal conductivity of 1 kcal/m.hr.°C. or more, and a volume resistivity of 10×10-3 W