A power generation cell includes a membrane electrode assembly, with an
anode side metal separator and a cathode side metal separator sandwiching
the membrane electrode assembly. Flow field walls are provided within the
coolant flow field for preventing coolant from flowing into an area
corresponding to an oxygen-containing gas inlet buffer, while allowing
the coolant to flow into an area corresponding to an oxygen-containing
gas outlet buffer. Likewise, flow field walls contact each other for
preventing the coolant from flowing into an area corresponding to a fuel
gas inlet buffer, while allowing the fuel gas to flow into an area
corresponding to a fuel gas outlet buffer.