A fuel cell system comprises a fuel cell having an anode flow path extending through the fuel cell between an anode inlet and an anode outlet, and a cathode flow path extending through the fuel cell between a cathode inlet and a cathode outlet. An anode purge valve is coupled to the anode outlet and has an outlet coupled to the cathode inlet. A purge valve controller is configured to effect a purge cycle by opening and closing the anode purge valve and to monitor a fuel cell voltage profile during the purge cycle to determine an operational state of the anode purge valve. A fuel cell voltage drop during a period following a command signal instructing opening of the anode purge valve is used to indicate successful start of a purge cycle. A fuel cell voltage rise during a period following a command signal instructing closing of the anode purge valve is used to indicate a successful end to a purge cycle.

A fuel cell system includes a fuel cell, a fuel gas supply line, an oxidizing agent gas supply line, a fuel gas discharge line, and a reformer provided in the fuel gas supply line. A first circulating line circulates the fuel gas from the fuel gas discharge line to an upstream side of the reformer in the fuel gas supply line as a first circulating gas. The circulation device is provided in the fuel gas supply line, and suctions the first circulating gas by using the flow of the fuel gas flowing through the fuel gas supply line as a driving flow. A second circulating line circulates the fuel gas from a downstream side of the circulation device in the fuel gas supply line or the fuel gas discharge line to the upstream side of the circulation device in the fuel gas supply line as a second circulating gas.

A fuel cell controller for controlling the operation of a fuel cell system comprising a plurality of fuel cells arranged together to provide electrical current at an output, the controller configured to actively set an upper limit on the rate of change in current provided by the fuel cell system at the output based on at least one electrical parameter of one or more of the fuel cells such as the lowest voltage (V.sub.MCV) of an individual fuel cell among a plurality of fuel cells.

A fuel cell system includes a fuel cell a temperature acquisition unit that acquires a temperature of the fuel cell, a cell unit voltage sensor that detects a voltage of each of fuel cell units, and a controller that controls the fuel cell system. The controller restricts an output current of the fuel cell when the voltage of the individual fuel cell unit becomes equal to or lower than a predetermined value in a warm-up operation, execute the warm-up operation when the temperature of the fuel cell is equal to or lower than a predetermined temperature, after the fuel cell system receives a start-up request, and stop an operation of the fuel cell system when a stop condition including that the voltage of the fuel cell unit is continuously equal to or lower than a predetermined voltage value for a predetermined time is satisfied after start of the warm-up operation.

A fuel cell system includes a fuel cell a current sensor that detects a current of the fuel cell, a plurality of cell voltage sensors that detects a voltage in a unit of one or two or more cells of the fuel cell among the cells, a pump that adjusts a flow rate of the cooling medium, and a controller. The controller estimates, in a first case, a calorific value of the fuel cell using each detected cell voltage value and the detected current value, decides the flow rate of the cooling medium based on the estimated calorific value, and controls the operation of the pump such that the flow rate of the cooling medium is lower than that of a case where the estimated calorific value is the same in a normal operation of the fuel cell.

An output voltage prediction system for a fuel cell includes: a storage unit that stores a relationship between a logarithm of a cumulative deterioration index amount and an output voltage of the fuel cell when an output current of the fuel cell is within a predetermined current range, the cumulative deterioration index amount being a cumulative amount of a deterioration index amount related to progress of deterioration of the fuel cell; an input data acquisition unit that acquires the cumulative deterioration index amount of the fuel cell as input data; and a prediction unit that converts the input data acquired by the input data acquisition unit into a logarithm and predicts the output voltage of the fuel cell based on the logarithm of the input data and the relationship stored in the storage unit.

A process for starting a PEM fuel cell module includes blowing air through the cathode side of the module using external power. An amount hydrogen is released into the anode side of the module under a pressure greater than the pressure of the air on the cathode side, while the anode is otherwise closed. Cell voltages in the module are monitored for the appearance of a charged state sufficient to start the module. When the charged state is observed, the module is converted to a running state.

The present invention aims to provide a fuel battery system improved in reliability by accurately detecting when a fuel electrode gas or an air electrode gas has leaked. A fuel battery cell according to the present invention includes a first electrode, an electrolyte membrane, and a second electrode which are layered on a support substrate. Further, at least any one of the first electrode, the electrolyte membrane, and the second electrode is electrically isolated by an insulating member to form a first region and a second region. The insulating member is disposed at a position where the insulating member does not overlap with an opening portion of the support substrate (refer to FIG. 3).

A cell-monitoring connector is configured to be detachably mounted to a fuel cell. A housing configured such that a portion thereof is insertable into a receiving space. A pair of lever operators is configured to be movable by a first external pressure in a third direction that intersects the first direction and the second direction. A number of levers are coupled to the pair of lever operators inside the housing. The levers include latching protrusions configured to operate in connection with movement of the lever operators. The latching protrusions are movable between a first position at which the latching protrusions protrude in the third direction from an outer surface of the housing and a second position at which the latching protrusions do not protrude from the outer surface of the housing.

A fuel cell system includes a fuel cell stack made by stacking a plurality of cells and configured to generate power by being supplied with fuel gas and oxidation gas, a high-voltage battery configured to supplement the power generated by the fuel cell stack while being charged with the power generated by the fuel cell stack or being discharged, a converter provided between the fuel cell stack and the high-voltage battery and configured to change an output voltage or an output current of the fuel cell stack, a power control unit configured to control the fuel cell stack to generate power when the fuel cell stack is requested to be diagnosed, the power control unit being configured to adjust the output current of the fuel cell stack to a predetermined current, and a voltage sensing unit configured to sense a voltage of the fuel cell stack or voltages of the plurality of cells included in the fuel cell stack in the state in which the output current of the fuel cell stack is the predetermined current.