Patent ID: 8071250

Claim:
A fuel cell stack comprising at least three fuel cell units stacked via separators, each fuel cell unit having: a membrane electrode assembly having a fuel electrode and an oxidizer electrode disposed at both sides of a polymer electrolyte membrane; an oxidizer flow path forming member disposed on the oxidizer electrode side and having an opening portion for supplying an oxidizer therethrough; and an oxidizer flow rate regulating portion disposed at the opening portion of the oxidizer flow path forming member, for regulating a flow rate of the oxidizer flowing in the oxidizer flow path forming member, wherein when a flow rate [sccm] per given pressure of the oxidizer in the oxidizer flow path forming member is defined as a conductance C 1 , and a flow rate [sccm] per given pressure of the oxidizer at the opening portion at which the oxidizer flow rate regulating portion is disposed is defined as a conductance C 2 , the conductances have a relationship of C 1 >C 2 , and at least one inner fuel cell unit except the fuel cell units located at both ends of the fuel cell stack has a value of C 1 /C 2 which is larger than values of C 1 /C 2 of the fuel cell units located at both ends of the fuel cell stack.