Abstract: A porous plate used in a fuel cell is sealed with an essentially 100% active material and catalyst mixture. The mixture is absorbed into and fills essentially the entire void volume provided by the pores. The mixture is then thermally shocked to partially cure the mixture thereby preventing wicking. The partially cured mixture is then post cured by elevating the temperature such that the catalyst initiates free radical polymerization. Since the sealant is essentially 100% active, there are no escape paths formed during the curing process, and the final seal is essentially 100% leak proof.

Abstract: The edges of a porous substrate plate used in a fuel cell power plant are densified by impregnating a suspension of finely divided material in the interstitial spaces in the plate edges. The suspension, in the form of an "ink" is forced into the plate edges via a pressure differential applied through the plate between two press blocks. The ink is forced into the plate after a catalyst layer has been applied to one surface of the substrate plate. The ink thus penetrates to the inner surface of the catalyst layer, and also forms an integral filler band outwardly of the catalyst layer, which filler band has a top surface which is coplanar with the top surface of the catalyst layer. After the impregnation step, the seals are dried to form a dense low porosity border on the substrate plates which will fill with electrolyte to form a wet seal that prevents gas crossover through the edges of the substrate plates.

Abstract: The edges of a porous substrate plate used in a fuel cell power plant are densified by impregnating a suspension of finely divided material in the interstitial spaces in the plate edges. The suspension, in the form of an "ink" is forced into the plate edges via a pressure differential applied through the plate between two press blocks. The ink is forced into the plate after a catalyst layer has been applied to one surface of the substrate plate. The ink thus penetrates to the inner surface of the catalyst layer, and also forms an integral filler band outwardly of the catalyst layer, which filler band has a top surface which is coplanar with the top surface of the catalyst layer. After the impregnation step, the seals are dried to form a dense low porosity border on the substrate plates which will fill with electrolyte to form a wet seal that prevents gas crossover through the edges of the substrate plates.

Abstract: A matrix for retaining the electrolyte in a fuel cell is applied to the surface of one or both of the electrodes by screen printing using an inking vehicle which is an aqueous solution of polyethylene oxide. This method produces a very thin, continuous and uniform matrix layer and is well suited to production operations.

Abstract: A matrix for retaining the electrolyte in a fuel cell is applied to the surface of one or both of the electrodes by screen printing. In a preferred embodiment an aqueous solution of glycol is used as the inking vehicle to screen print a very thin, continuous and uniform matrix layer on the surface of an electrode.