Fuel Cell System
AssigneeToyota Jidosha Kabushiki Kaisha
InventorNobuyuki Kitamura
Life of this patent
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Abstract
In a fuel cell system including a stack of polymer electrolyte fuel cells, the wet state of electrolyte membranes in the fuel cell stack is detected according to a variation in measurement value of an alternating current impedance (AC impedance) of the fuel cell stack. In an adequate level of water content of the electrolyte membranes, the measurement value of the AC impedance is substantially constant and has a very little variation. In an excess level of water content of the electrolyte membranes, the measurement value of the AC impedance has a significant variation. The AC impedance of the fuel cell stack is determinable by frequency analysis of high-frequency noise generated by an inverter included in the fuel cell system.
Claims10
A fuel cell system, comprising:
- a fuel cell that has a solid polymer electrolyte membrane;
- a measurement module that measures an alternating current impedance of the fuel cell in time series;
- a computation module that computes a value of a preset parameter, which is related to a variation in measurement value of the alternating current impedance, from time series data of the measured alternating current impedance;
- and
- a detection module that detects a wet state of the electrolyte membrane, based on the computed value of the preset parameter.
A fuel cell system, comprising:
- a fuel cell that has a solid polymer electrolyte membrane;
- an output controller that controls an output of the fuel cell;
- and
- a measurement module that measures an alternating current impedance of the fuel cell in time series,
- the measurement module performing frequency analysis of high-frequency noise generated by the output controller to determine the alternating current impedance.
A detection method applied to a fuel cell having a solid polymer electrolyte membrane to detect a wet state of the electrolyte membrane, the detection method comprising:
- (a) measuring an alternating current impedance of the fuel cell in time series;
- (b) computing a value of a preset parameter, which is related to a variation in measurement value of the alternating current impedance, from time series data of the measured alternating current impedance;
- and
- (c) detecting the wet state of the electrolyte membrane, based on the computed value of the preset parameter.
A control method of a fuel cell system that includes a fuel cell having a solid polymer electrolyte membrane, the control method comprising:
- (a) measuring an alternating current impedance of the fuel cell in time series;
- (b) computing a value of a preset parameter, which is related to a variation in measurement value of the alternating current impedance, from time series data of the measured alternating current impedance;
- (c) detecting a wet state of the electrolyte membrane, based on the computed value of the preset parameter;
- and
- (d) regulating a water content of the electrolyte membrane according to a result of the detection.
Dependencies are inferred from the claim text.