Fuel cell system and fuel cell system operating method

Abstract

In a fuel cell system equipped with polymer electrolyte fuel cells, an alternating current generator applies an alternating current of a fixed frequency and a fixed amplitude to the fuel cells. An alternating current voltage acquisition module (combination of a filter unit and an A-D converter with a controller) extracts an alternating current component attributed to the application of the alternating current from an output voltage in a specific unit cell of the fuel cells and time-sequentially obtains a voltage value of the extracted alternating current component. A moisture state monitoring module (the controller) identifies whether the fuel cells have a moistening tendency. In the case of identification of the moistening tendency of the fuel cells by the moisture state monitoring module, an over-hydration detection module (the controller) computes a statistical value representing a magnitude of a variation in time-sequentially obtained voltage value of the alternating current component and determines that the fuel cells are in an over-hydration state when the computed statistical value representing the magnitude of the variation exceeds a preset reference level.

Description

technical field [0001] The present invention relates to a fuel cell system including a fuel cell and an operating method of the fuel cell system. Background technique [0002] For solid polymer fuel cells, since a solid polymer membrane that exhibits proton conductivity in a wet state is used as an electrolyte layer, it is important to keep the solid polymer membrane sufficiently wet in order to maintain a good power generation state. state. Moreover, in such a fuel cell, although water is generated at the cathode along with power generation, when the generation of water is excessive or the discharge of generated water is delayed, a state called flooding will be formed, and there will be a gap with respect to the cathode catalyst. Insufficient gas supply. Therefore, conventionally, control for properly maintaining the amount of water contained in the electrolyte layer, the catalyst, and its surroundings has been performed. In order to control the amount of moisture in thi...

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Problems solved by technology

Moreover, in such a fuel cell, although water is generated at the cathode along with power generation, when the generation of water is excessive or the discharge of generated water is delayed, a state called flooding will be formed, and there will be a gap with respect to the cathode catalyst. Insufficient gas supply

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