Fuel cell system
First Claim
1. A fuel cell system, comprising:
- a fuel cell that has a solid polymer electrolyte membrane;
a measurement module configured to measure values of an alternating current impedance of the fuel cell in time series while the fuel cell system is in operation;
a computation module configured to compute a variance from the measured values of the alternating current impedance; and
a detection module configured to detect a wet state of the electrolyte membrane, based on the variance.
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Accused Products
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.
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Citations
9 Claims
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1. A fuel cell system, comprising:
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a fuel cell that has a solid polymer electrolyte membrane; a measurement module configured to measure values of an alternating current impedance of the fuel cell in time series while the fuel cell system is in operation; a computation module configured to compute a variance from the measured values of the alternating current impedance; and a detection module configured to detect a wet state of the electrolyte membrane, based on the variance. - View Dependent Claims (2, 3, 4, 5, 6)
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7. 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:
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(a) measuring values of an alternating current impedance of the fuel cell in time series while the fuel cell is in operation; (b) computing a variance from the measured values of the alternating current impedance; and (c) detecting the wet state of the electrolyte membrane, based on the variance.
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8. A control method of a fuel cell system that includes a fuel cell having a solid polymer electrolyte membrane, the control method comprising:
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(a) measuring values of an alternating current impedance of the fuel cell in time series while the fuel cell system is in operation; (b) computing a variance from the measured values of the alternating current impedance; (c) detecting a wet state of the electrolyte membrane, based on the variance; and (d) regulating a water content of the electrolyte membrane according to a result of the detection. - View Dependent Claims (9)
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Specification