Fuel cell cassette and fuel cell stack

A fuel cell cassette, comprising:

• a single cell formed in a flat plate shape and having a fuel electrode, an air electrode and an electrolyte layer stacked together in a stacking direction;
• a first frame formed in a frame shape and arranged to surround a peripheral surface of the single cell;
• a separator joined to a peripheral end portion of the single cell and located on one surface of the first frame so as to separate an oxidant gas contacting the air electrode and a fuel gas contacting the fuel electrode;
• and
• an interconnector formed in a plate shape and located on the other surface of the first frame opposite to the one surface on which the separator is located,
• wherein the separator and the first frame are joined by welding such that the first frame is located on one surface of the separator;
• wherein the fuel cell cassette comprises:
• a second frame located on the other surface of the separator which is opposite from the first frame in the stacking direction, the second frame having defined therein gas channels through which the oxidant gas or the fuel gas flows;
• and
• a welding part formed on an exposed region of the separator inside the gas channel so as to fix the exposed region of the separator to the first frame;
• and
• wherein the entire first frame consists of metal and the entire second frame consists of an insulating material,
• wherein each of the first frame and the second frame has a monolithic structure;
• and
• wherein the first frame and the second frame are separately provided and spaced apart from each other.