Liquid fuel mixing apparatus and direct liquid feed fuel cell system including the same

A direct liquid feed fuel cell system, comprising:

• a direct liquid feed fuel cell stack comprising at least two membrane electrode assemblies, wherein each membrane electrode assembly comprises an electrolyte membrane having a first surface and a second surface, an anode formed on the first surface, and a cathode formed on the second surface;
• at least one conductive bipolar plate that contacts the anode of one membrane electrode assembly and the cathode of another membrane electrode assembly;
• an upper conductive end plate arranged at the upper end of the fuel cell that contacts an uppermost membrane electrode assembly;
• a lower conductive end plate arranged at the lower end of the fuel cell that contacts a lowermost membrane electrode assembly;
• a plurality of through-holes arranged substantially vertically through the fuel cell stack that allow fuel supply or discharge;
• a liquid fuel tank;
• and
• a liquid fuel mixing apparatus that mixes a liquid fuel from the liquid fuel tank and unreacted fuel and water from the through-holes and supplies a mixed fuel to the anode,
• wherein the liquid fuel mixing apparatus comprises:
• a water chamber;
• a fuel chamber;
• and
• a partition arranged substantially vertically between the water chamber and the fuel chamber,
• wherein the partition comprises a passage to permit communication between the water chamber and the fuel chamber,
• wherein the water chamber comprises a first port for the inflow of water and air recovered from the cathode of the fuel cell stack, and
• wherein the fuel chamber comprises a third port for the inflow of unreacted fuel and CO2 from the anode of the fuel cell stack, a fourth port for the inflow of the liquid fuel from the liquid fuel tank, and a fifth port for the outflow of mixed fuel to the fuel cell stack.