Patent ID: 7354670

Claim:
A fuel cell, comprising: a first stack having a plurality of unit cells; a second stack having a plurality of unit cells, the second stack being separate from the first stack, wherein each of said plurality of unit cells of the first and second stacks has a membrane electrode assembly including an anode, a cathode, and a solid polymer electrolyte membrane interposed between said anode and said cathode, wherein the first stack and the second stack have reactant gas passages and coolant passages defined at least partly therein and the reactant gas passages and the coolant passages are connected in series with each other across said plurality of unit cells for supplying or circulating one or more reactant gases and a coolant to said first and second stacks; a fuel gas outlet/inlet passage connecting a fuel gas passage from the first stack with a fuel gas passage from the second stack for passing a fuel gas therethrough; and a fuel gas adjusting mechanism connected to said fuel gas outlet/inlet passage for controlling the flow rate and direction of said fuel gas, wherein the first stack and the second stack generate electric power simultaneously in use and are electrically connected in series.