FUEL CELL STACK

A fuel cell stack includes a reaction layer having a MEA, an anode separator having a gas channel formed at a first side facing the reaction layer and through which a first reactant gas flows, and a cooling channel formed at a second side and through which a coolant flows. The anode separator abuts the reaction layer. A cathode separator abuts anode separator so that a first side of the cathode separator covers the cooling channel. A porous structural unit has a partition wall protruding from the second side of the cathode separator and has a flow path for a second reactant gas to minimize a cooling temperature deviation and improve operational efficiency.