Abstract: A lamellar structure graphite foil is used as a material for a separator for a fuel cell, and a hydrophobic layer is formed by impregnation on flow-field channels of the graphite foil. Such a separator is manufactured by forming the flow field channel by etching the graphite foil formed with the mask pattern thereon and forming a hydrophobic layer by impregnation. According to such a separator, performance of a fuel cell stack is enhanced and the manufacturing process of a separator is simplified.

Abstract: Disclosed is a cell voltage monitoring apparatus for monitoring output voltages of a plurality of unit cells in a cell having the unit cells. The cell voltage monitoring apparatus includes: a reference voltage generator for generating a predetermined reference voltage from the unit cell generation voltage; a voltage comparator for comparing a generation voltage of a monitor unit cell and the reference voltage; a signal separator for outputting a signal that is electrically separated from an output signal of the voltage comparator; and an operation processor for determining normality of the cell voltage from a signal output by the signal separator.

Abstract: Disclosed is a cell voltage monitoring apparatus for monitoring output voltages of a plurality of unit cells in a cell having the unit cells. The cell voltage monitoring apparatus includes: a reference voltage generator for generating a predetermined reference voltage from the unit cell generation voltage; a voltage comparator for comparing a generation voltage of a monitor unit cell and the reference voltage; a signal separator for outputting a signal that is electrically separated from an output signal of the voltage comparator; and an operation processor for determining normality of the cell voltage from a signal output by the signal separator.

Abstract: A fuel cell separator, a fuel cell stack having the fuel cell separator, and a reactant gas control method of the fuel cell stack are provided. That is, even when the fuel cell stack operates under the low load operation condition, a reactant gas is supplied to the reactant gas passages of the fuel cell separator, and thus, the length of the passage can be shortened by 50% as compared with the prior art having only one reactant gas passage. Therefore, the reactant gas can be effectively supplied without experiencing pressure loss. Further, in the high load operation of the fuel cell stack, the reactant gas is introduced into the first reactant gas passage of the fuel cell separator and utilized in half of the whole electrode area. Subsequently, the reactant gas is introduced into the second reactant gas passage and utilized in the remaining half of the electrode area.

Abstract: A fuel cell system includes a fuel cell stack generating electric power using an electrochemical reaction between hydrogen and oxygen, a fuel process unit supplying reformed gas to the fuel cell stack by reforming an electricity generation material into the reformed gas that is rich in hydrogen, and an air supply unit supplying air containing oxygen to the fuel cell stack. The air supply unit includes an intake passage that extends from an outside space to the fuel cell stack, a first air pump that is installed on the intake passage to allow the air to be introduced into the fuel cell stack, and a first pressure buffer container that is disposed between the first air pump and the fuel cell stack to reduce pressure of the air flowing along the intake passage to a level less than a predetermined pressure.

Abstract: A lamellar structure graphite foil is used as a material for a separator for a fuel cell, and a hydrophobic layer is formed by impregnation on flow-field channels of the graphite foil. Such a separator is manufactured by forming the flow field channel by etching the graphite foil formed with the mask pattern thereon and forming a hydrophobic layer by impregnation. According to such a separator, performance of a fuel cell stack is enhanced and the manufacturing process of a separator is simplified.