摘要 |
Provided is a fuel cell system capable of accurately estimating I-V characteristics of a fuel cell. An impedance measurement section measures an impedance of the fuel cell and obtains a voltage drop caused by a direct-current resistance. An air stoichiometry judgment section detects the amount of oxidant gas supplied to the fuel cell and thereby judges whether or not the air stoichiometry ratio is 1 or higher at this time point. An estimated I-V characteristics line creation section determines that the remaining voltage component consists entirely of an activation voltage when the air stoichiometry ratio notified by the air stoichiometry judgment section is 1 or higher, while determining that the remaining voltage drop component includes the combination of the activation overvoltage and voltage drop corresponding to the change in the electromotive voltage when the notified air stoichiometry ratio is below 1.
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