Abstract: Electrolyte is replenished in a fully assembled stack of fuel cells by depositing dilute electrolyte on tabs extending outwardly from an external vertical face of the stack. The electrolyte is absorbed into the cell components as it cascades off the tabs and down the face of the stack. When the electrodes and matrix layers of the stack are fully saturated the stack is heated and water is evaporated until the stack has an operable electrolyte volume and electrolyte concentration therein. In a preferred embodiment the tabs are extensions of the nonporous plates separating adjacent cells in the stack.

Abstract: A cooler assembly for a stack of fuel cells comprises a fibrous, porous coolant tube holder sandwiched between and bonded to at least one of a pair of gas impervious graphite plates. The tubes are disposed in channels which pass through the holder. The channels are as deep as the holder thickness, which is substantially the same as the outer diameter of the tubes. Gas seals along the edges of the holder parallel to the direction of the channels are gas impervious graphite strips.