Patent ID: 7670700

Claim:
A fuel cell system comprising: a fuel cell comprising: an electrolyte membrane and a first electrode and a second electrode placed on both sides of the electrolyte membrane, respectively; an oxidant gas inlet portion for introducing oxidant gas into the fuel cell; an oxidant gas flow channel connected to the oxidant gas inlet portion to supply the oxidant gas into an inside of the electrolyte membrane; an oxidant gas outlet portion connected to the oxidant gas flow channel for exhausting residual oxidant gas from the electrolyte membrane to the outside; a fuel gas inlet portion for introducing fuel gas into the fuel cell; a fuel gas flow channel connected to the fuel gas inlet portion to supply the fuel gas into the inside of the electrolyte membrane; and a fuel gas outlet portion for exhausting residual fuel gas from the electrolyte membrane to the outside, the fuel cell being operative to electrochemically react the oxidant gas and the fuel gas to generate electric energy; a current measuring device located on at least one of the oxidant gas inlet portion, the oxidant gas outlet portion, the fuel gas inlet portion and the fuel gas outlet portion for detecting a localized current present therein; and a diagnosis device for diagnosing a drying state of an internal part of the fuel cell based on the localized current measured by the current measuring device; wherein: the electrolyte membrane includes a membrane electrode assembly; the first electrode includes a positive electrode current collector placed on one side of the membrane electrode assembly; the second electrode includes a negative electrode current collector placed on another side of the membrane electrode assembly, which has a main current collector plate placed in close proximity to the fuel gas channel and an auxiliary current collector plate placed in close proximity to at least one of the fuel gas inlet portion and the fuel gas outlet portion; and the current measuring device is connected between the main current collector plate and the auxiliary current collector plate.