(US4756981-A)      Electrochemical cell assembly (I) includes a porous plate (II) and an edge seal which extends about the periphery of (II) to block leakage of gas in the lateral direction. (I) also includes means for blocking the leakage of gas from the cell in a second direction, which is normal to the lateral direction.    The improvement comprises means for blocking the leakage of a gas from the cell in the second direction which includes (a) a gas permeable, hydrophobic liq. barrier which extends to block the movement of liq. in the second direction; and (b) a seal region, which extends as a portion of (II) in the lateral direction to the edge seal. The seal region has a first pore size distribution (II) also has a region spaced from the seal region and from the edge seal which has a second pore size distribution. The first pore size distribution is smaller than the second pore size distribution, and has a capillary characteristic which adapts the seal region to form a hydrophilic gas barrier which extends in the second direction to the hydrophobic liq. barrier and laterally to the edge seal.    ADVANTAGE -   Decreased gas permeability of a seal structure having two different types of barriers, relative to structures having only a single barrier.    (US4824739-A)      Seal structure (60) for a porous plate of an electrochemical cell, e.g. fuel cell power plant, consisting of stacked fuel cells (4), includes a gas-permeable, hydrophobic liq. barrier (62) which is part of the cathode electrolyte reservoir plate (20) of the fuel cell. The seal structure also has a hydrophilic seal region (66) which is part of the porous electrolyte reservoir plate (18). This seal region is filled with electrolyte which extends to the face (64) of the hydrophobic liq. barrier. A second hydrophilic seal region may be provided in the void structure of the porous electrolyte reservoir plate, filled with electrolyte which also extends to the liq. barrier.    ADVANTAGE -   Decreased gas permeability compared with structures having a single barrier.