Self-sealing fuel cell separator

A fuel cell comprising an membrane-electrode assembly and a first metal separator and a second metal separator disposed, respectively, on each side of said membrane-electrode assembly, each of said metal separators defining a fluid passage, said fluid passage defining a reactant gas passage formed at a first, membrane-electrode assembly-opposing surface of said metal separator, a coolant passage formed at a second, opposite surface of said metal separator, a reactant gas manifold fluidly connected to said reactant gas passage and a coolant manifold fluidly connected to said coolant passage, said fuel cell having first and second sides and being adapted to be piled with other fuel cells to construct a stack of fuel cells,

• wherein said first metal separator includes a plurality of convex and concave stamped passages and a rib made from said metal formed thereon so as to surround a portion of said first metal separator where said fluid passage is formed, said rib being adapted to metal-to-metal contact a flat side of a metal separator of an adjacent fuel cell to construct a seal for a fluid passage surrounded by said rib, a seal line constructed by said rib extending around said portion of the first metal separator where said fluid passage is formed,
• wherein said rib is integral with said first metal separator, and said rib protrudes in a direction away from a first side of the fuel cell and said rib has a top portion having a cross-sectional shape in the form of a convex arcuate surface, and said rib is located on only said first metal separator protruding away from said first side of said fuel cell, and
• wherein said rib has a plate thickness to provide elasticity, the plate thickness of said rib being constant and substantially equal to a thickness of each of the first and second separators.

A fuel cell comprising an membrane-electrode assembly and a first metal separator and a second metal separator disposed, respectively, on each side of said membrane-electrode assembly, each of said metal separators defining a fluid passage, said fluid passage defining a reactant gas passage formed at a first, membrane-electrode assembly-opposing surface of said metal separator, a coolant passage formed at a second, opposite surface of said metal separator, a reactant gas manifold fluidly connected to said reactant gas passage and a coolant manifold fluidly connected to said coolant passage, said fuel cell having first and second sides and being adapted to be piled with other fuel cells to construct a stack of fuel cells,

• wherein said first metal separator includes a plurality of convex and concave stamped passages and a rib made from said metal formed thereon so as to surround a portion of said first metal separator where said fluid passage is formed, said rib being adapted to metal-to-metal contact a flat side of a metal separator of an adjacent fuel cell to construct a seal for a fluid passage surrounded by said rib, a seal line constructed by said rib extending around said portion of the first metal separator where said fluid passage is formed,
• wherein said rib is integral with said first metal separator, and said rib protrudes in a direction away from a first side of the fuel cell and said rib has a top portion having a cross-sectional shape in the form of a trapezoidal convex surface, and said rib is located on only said first metal separator protruding away from said first side of said fuel cell, and
• wherein said rib has a plate thickness to provide elasticity, the plate thickness of said rib being constant and substantially equal to a thickness of each of the first and second separators.