In a fuel cell provided with a pair of separators sandwiching a cell that includes an electrolyte and a fuel electrode and an air electrode provided on respective sides of the electrolyte, gas passages in a separator adjacent to the fuel electrode are opposite to flat surfaces of a separator adjacent to the air electrode. Also, gas passages in the separator adjacent to the air electrode are opposite to flat surfaces of the separator adjacent to the fuel electrode.
1. A fuel cell comprising:
a membrane electrode assembly including an electrolyte and a pair of electrodes provided on respective sides of the electrolyte; and
a first separator and a second separator sandwiching said membrane electrode assembly, wherein
said first separator is provided with a first passage comprising a plurality of recesses formed on a first separator surface in contact with said membrane electrode assembly,
said second separator is provided with a second passage comprising a plurality of recesses formed on a second separator surface in contact with said membrane electrode assembly,
the recesses of said first separator are opposite, across said membrane electrode assembly, to the second separator surface in contact with said membrane electrode assembly,
the recesses of said second separator are opposite, across said membrane electrode assembly, to the first separator surface in contact with said membrane electrode assembly, and
a sum of the width of the recess constituting the first passage and an interval between the recesses constituting the first passage is different from a sum of the width of the recess constituting the second passage and an interval between the recesses constituting the second passage.
2. The fuel cell according to claim 1 , wherein the plurality of recesses constituting the first passage and the plurality of recesses constituting the second passage extend in one direction and parallel with each other.
3. The fuel cell according to claim 2 , wherein the plurality of recesses constituting the first passage and the plurality of recesses constituting the second passage have substantially the same cross-sectional configuration and are formed at regular intervals.
4. The fuel cell according to claim 3 , wherein the depth of the recesses constituting the first passage is greater than the width of the recesses constituting the first passage.