Single cell of fuel cell

A single cell of a fuel cell for constituting a stack, the single cell comprising:

• a membrane-electrode assembly;
• and
• a first separator and a second separator holding the membrane-electrode assembly therebetween, wherein
• the first separator has plural first groove channels that are straight or wavy and that are arranged in parallel to each other in a first in-plane direction,
• a cross section along the first in-plane direction of each of the plural first groove channels has a first uneven shape,
• the first uneven shape has a first pitch P1 along the first in-plane direction,
• the second separator has plural second groove channels that are wavy and that are arranged along the first in-plane direction,
• a cross section along the first in-plane direction of each of the plural second groove channels has a second uneven shape,
• the second uneven shape has a second pitch P2 along the first in-plane direction,
• the first pitch P1 and the second pitch P2 differ from each other and neither a value of P1/P2 nor a value of P2/P1 is an integer, and
• a pattern of the plural first groove channels differs from a pattern of the plural second groove channels such that the first separator and second separator are asymmetrical with respect to the membrane-electrode assembly.