Patent ID: 7618729

Claim:
A liquid fuel direct supply fuel cell system, comprising: a generator having a plurality of cells connected serially or in parallel, wherein at least one of the cells has an anode and a cathode which are oppositely installed through a protonic conductive polymer electrolyte membrane, a liquid fuel is supplied from a fuel inlet to the anode and is exhausted from a fuel outlet, and an oxidizing agent gas is supplied from a gas inlet to the cathode and is exhausted from a gas outlet; a fuel tank for storing the liquid fuel to be supplied to the anode; a high concentration fuel tank for storing a high concentration fuel used for regulating a concentration of the liquid fuel in the fuel tank; and a water tank for storing water produced by a cell reaction of the generator, a sensor integrally installed with the generator and comprising a temperature detector and a monitor cell having a protonic conductive polymer electrolyte membrane, an anode and a cathode installed on both faces of the membrane, a fuel inlet for supplying the liquid fuel to the anode, a fuel outlet for exhausting the liquid fuel from the anode, a gas inlet for supplying an oxidizing agent gas to the cathode, and a gas outlet for exhausting the oxidizing agent gas from the cathode; the sensor detecting the concentration of the liquid fuel by a temperature compensated electromotive force, produced by compensating an electromotive force of the monitor cell by an output signal of the temperature detector, the fuel inlet and the fuel outlet of the sensor being communicated with the fuel inlet and the fuel outlet of the generator, respectively, and the oxidizing agent gas inlet and the oxidizing agent gas outlet of the sensor being communicated with the oxidizing agent gas inlet and the oxidizing agent gas outlet of the generator, respectively, and a controller for operating at least one of a control of a supply of the high concentration fuel from the high concentration fuel tank to the fuel tank, a control of a supply of water from the water tank to the fuel tank, and a control of a supply of the liquid fuel from the fuel tank to the generator, on the basis of the output signal from the sensor.