JP2012243664A - Fuel cell system and shutdown method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve efficient economical scavenging processing by detecting a region in a fuel cell in which a ground fault occurs with simple configuration and steps.SOLUTION: A fuel cell system 10 is a system which includes a plurality of stacked fuel cells 12, each having an electrolyte membrane-electrode structure 28, and performs electricity generation by electrochemical reaction of oxidant gas supplied to a cathode side of the fuel cells 12 and fuel gas supplied to an anode side of the fuel cells 12. A shutdown method of the fuel cell system 10 includes: the step of measuring an insulation resistance by a ground fault sensor 68 after suspension of operation; and the step in which when a determination is made that a ground fault occurs on either one of the cathode side and the anode side on the basis of the insulation resistance measured, at least the one electrode side is scavenged by scavenging means capable of supplying scavenging air to the cathode side and the anode side by using the scavenging air.

Description

  The present invention provides a stack of a plurality of fuel cells having an electrolyte membrane / electrode structure in which a cathode electrode and an anode electrode are provided on both sides of the electrolyte membrane, and an oxidant gas supplied to the cathode side of the fuel cell and the fuel The present invention relates to a fuel cell system that generates power by an electrochemical reaction of fuel gas supplied to the anode side of the battery, and a method for stopping the fuel cell system.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) provided with an anode electrode and a cathode electrode on both sides of an electrolyte membrane made of a polymer ion exchange membrane is sandwiched between a pair of separators. Yes. A fuel gas passage for supplying fuel gas to the anode electrode is formed between one separator and the electrolyte membrane / electrode structure, and between the other separator and the electrolyte membrane / electrode structure. Is formed with an oxidant gas flow path for supplying an oxidant gas to the cathode electrode.

  In general, a plurality of fuel cells are stacked to form a fuel cell stack, and are used as an in-vehicle fuel cell system by being incorporated in a fuel cell vehicle for in-vehicle use as well as for stationary use.

  In this type of fuel cell, water is generated at the cathode electrode due to the reaction between hydrogen and oxygen during power generation, while the water is back-diffused through the electrolyte membrane at the anode electrode. For this reason, in order to discharge generated water from the fuel cell, it is necessary to scavenge the inside of the fuel cell. This is because the generated water staying in the fuel cell electrically connects the fuel cell and the auxiliary equipment provided outside, and the fuel cell may be grounded.

  For this reason, for example, an operation control method for a fuel cell system disclosed in Patent Document 1 is known. The operation control method includes a step of preparing a fuel cell system including a fuel cell having a fuel electrode and an oxidant electrode, a step of continuing the power generation operation of the fuel cell of the fuel cell system, and a power generation operation of the fuel cell. When an end command is output to end the fuel cell, the fuel is continuously supplied to the fuel electrode of the fuel cell, and the oxidant gas is continuously supplied to the oxidant electrode of the fuel cell, By supplying an oxidant gas having a flow rate larger than the flow rate during normal power generation operation to the oxidant electrode of the fuel cell while continuing the power generation operation of the fuel cell, the inside of the oxidant electrode of the fuel cell And a scavenging process for scavenging.

JP 2010-21024

  However, in Patent Document 1 described above, when the fuel cell is stopped, the flow rate of the oxidant gas is increased, so that energy is consumed to increase the output of the oxidant pump. In addition, since the fuel gas is continuously supplied, the fuel gas is wasted and is not economical.

  The present invention solves this type of problem, and with a simple configuration and process, it is possible to detect a site where a ground fault occurs in the fuel cell and perform an efficient and economical scavenging process. An object of the present invention is to provide a fuel cell system and a method for stopping the fuel cell system.

  The present invention provides a stack of a plurality of fuel cells having an electrolyte membrane / electrode structure in which a cathode electrode and an anode electrode are provided on both sides of the electrolyte membrane, and an oxidant gas supplied to the cathode side of the fuel cell and the fuel The present invention relates to a fuel cell system that generates electric power by an electrochemical reaction of fuel gas supplied to the anode side of the battery and a method for stopping the fuel cell system.

  The fuel cell system includes an oxidant gas communication hole that allows an oxidant gas to flow in the stacking direction of the fuel cell, a fuel gas communication hole that allows a fuel gas to flow in the stacking direction, the oxidant gas communication hole, and the fuel gas. A detection electrode disposed in the communication hole, and a ground fault detection unit that determines whether or not a ground fault has occurred by measuring a voltage or a current between the output terminal of the fuel cell and the detection electrode; And scavenging means for supplying scavenging air to the cathode side and the anode side.

  In addition, in this stopping method, after the operation is stopped, a ground fault occurs on either the cathode side or the anode side based on the step of measuring the insulation resistance by the ground fault sensor and the measured insulation resistance. A step of scavenging at least one of the polar sides with the scavenging air by a scavenging means capable of supplying scavenging air to the cathode side and the anode side.

  Further, in this stopping method, after scavenging one pole side, it is determined whether or not a ground fault has occurred on the other pole side of the cathode side or the anode side, and a ground fault is caused on the other pole side. It is preferable to have a step of scavenging the other pole side with the scavenging air when it is determined that the above has occurred.

  Furthermore, the stop method includes an oxidant gas communication hole for flowing an oxidant gas in the stacking direction of the fuel cell, a detection electrode disposed in the fuel gas communication hole for flowing the fuel gas in the stacking direction, A step of measuring a voltage or current between the output terminal of the fuel cell and a determination that a ground fault has occurred on either the cathode side or the anode side based on the measured voltage or current And a step of scavenging the one pole side with the scavenging air by a scavenging means capable of supplying scavenging air to the cathode side and the anode side.

  In the present invention, by measuring the voltage or current between the detection electrode disposed in the oxidant gas communication hole and the fuel gas communication hole and the output terminal of the fuel cell, the site where the ground fault occurs can be accurately and easily determined. Detected. Therefore, the scavenging air can be reliably supplied to the pole side where the ground fault has occurred via the scavenging means.

  Accordingly, it is possible to detect a site where a ground fault occurs in the fuel cell with a simple configuration and process, and to perform an efficient and economical scavenging process.

  Further, in the present invention, after the fuel cell is stopped, at least one of the cathode side and the anode side can be scavenged by the scavenging means based on the measured insulation resistance. At that time, it is possible to scavenge via the scavenging means regardless of whether the pole where the ground fault has occurred is on the cathode side or the anode side.

  As a result, it is possible to detect a site where a ground fault occurs in the fuel cell by a simple process and to perform an efficient and economical scavenging process.

1 is a schematic configuration diagram of a fuel cell system according to a first embodiment of the present invention. It is a flowchart explaining the said stop method. It is a timing chart explaining the said stop method. It is a schematic block diagram of the fuel cell system which concerns on the 2nd Embodiment of this invention. It is a cross-sectional side view of the fuel cell stack which comprises the said fuel cell system. 2 is an exploded perspective view of a fuel cell constituting the fuel cell stack. FIG. It is front explanatory drawing of the state by which the detection electrode is arrange | positioned at the insulation plate which comprises the said fuel cell stack. It is a flowchart explaining the said stop method.

  As shown in FIG. 1, the fuel cell system 10 according to the first embodiment of the present invention constitutes an in-vehicle fuel cell system, for example.

  The fuel cell system 10 includes a fuel cell stack 14 in which fuel cells 12 are stacked, an air supply system 16 that supplies air as an oxidant gas to the fuel cell stack 14, and hydrogen as a fuel gas to the fuel cell stack 14. A hydrogen supply system 18 to be supplied and a control unit 20 that controls the entire system are provided.

  Each fuel cell 12 includes, for example, an electrolyte membrane / electrode structure (MEA) 28 in which a solid polymer electrolyte membrane 22 in which a perfluorosulfonic acid thin film is impregnated with water is sandwiched between a cathode electrode 24 and an anode electrode 26. .

  The cathode electrode 24 and the anode electrode 26 have a gas diffusion layer made of carbon paper or the like, and porous carbon particles carrying platinum alloy (or Ru or the like) on the surface are uniformly applied to the surface of the gas diffusion layer. And an electrode catalyst layer formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 22.

  The electrolyte membrane / electrode structure 28 is sandwiched between the cathode side separator 30 and the anode side separator 32. The cathode side separator 30 and the anode side separator 32 are comprised by a carbon separator or a metal separator, for example.

  An oxidant gas flow path 34 is provided between the cathode side separator 30 and the electrolyte membrane / electrode structure 28, and a fuel gas is provided between the anode side separator 32 and the electrolyte membrane / electrode structure 28. A flow path 36 is provided. A cooling medium flow path 38 is provided between the cathode side separator 30 and the anode side separator 32.

  The fuel cell stack 14 communicates with each other in the stacking direction of the fuel cells 12, and includes an air inlet communication hole 40a for supplying air, a hydrogen gas inlet communication hole 42a for supplying hydrogen gas, and a cooling medium inlet for supplying a cooling medium. A communication hole (not shown), an air outlet communication hole 40b for discharging the air, a hydrogen gas outlet communication hole 42b for discharging the hydrogen gas, and a cooling medium outlet communication hole (not shown) for discharging the cooling medium. Provided.

  The air supply system 16 includes an air pump that compresses and supplies air from the atmosphere. One end of an air supply path 44 is connected to the air supply system 16, and the other end of the air supply path 44 communicates with the air inlet communication hole 40 a of the fuel cell stack 14 through a humidifier 46.

  One end of a cathode offgas discharge path 48 communicates with the air outlet communication hole 40 b of the fuel cell stack 14. The other end of the cathode offgas discharge path 48 is connected to the dilution box 50 through the humidifier 46.

  The humidifier 46, between the external air introduced through the air supply path 44 and the high-temperature and high-humidity cathode offgas discharged from the fuel cell stack 14 and flowing through the cathode offgas discharge path 48, Exchange heat.

  The hydrogen supply system 18 includes, for example, a hydrogen tank filled with high-pressure hydrogen, and one end of a hydrogen supply path 52 is connected to the hydrogen supply system 18. The hydrogen supply path 52 communicates with the hydrogen gas inlet communication hole 42 a of the fuel cell stack 14. A supply amount adjustment valve 54 and an ejector 56 are disposed in the hydrogen supply path 52.

  One end of an anode offgas discharge path 58 is connected to the hydrogen gas outlet communication hole 42 b of the fuel cell stack 14. A hydrogen discharge valve 60 is disposed in the anode off gas discharge path 58, and an anode off gas circulation path 62 is connected to the upstream side of the hydrogen discharge valve 60 and the ejector 56.

  One end of a bypass path 64 is connected to the air supply path 44 upstream of the humidifier 46, and the other end of the bypass path 64 is connected to the hydrogen supply path 52 downstream of the ejector 56. An open / close valve 66 is disposed in the bypass path 64.

  The control unit 20 controls the entire system and receives a resistance value detection signal at a predetermined part from the ground fault sensor 68. The control unit 20 stores a threshold value of an insulation resistance value that may cause a ground fault. By comparing with a resistance value detection signal output from the ground fault sensor 68, a ground fault is generated in the fuel cell stack 14. Detect whether it has occurred.

  The ground fault sensor 68 is disclosed by Unexamined-Japanese-Patent No. 2004-170103, for example. That is, the ground fault sensor 68 applies the voltage of the fuel cell 12 to the capacitor for a predetermined time, and then compares the potential generated in the capacitor with the potential generated in the capacitor via the ground potential portion. Measure the insulation resistance.

  The operation of the fuel cell system 10 configured as described above will be described below.

  First, air is sent to the air supply path 44 via the air supply system 16, while hydrogen gas is sent to the hydrogen supply path 52 via the hydrogen supply system 18.

  The air supplied to the air supply path 44 is humidified and heated through the humidifier 46 and then supplied to the air inlet communication hole 40 a of the fuel cell stack 14. This air is supplied to the cathode electrode 24 by moving along the oxidant gas flow path 34 provided in each fuel cell 12 in the fuel cell stack 14.

  Used air (hereinafter also referred to as cathode offgas) is discharged from the air outlet communication hole 40b to the cathode offgas discharge path 48. This cathode off gas is sent to the humidifier 46, humidifies and warms the air newly supplied along the air supply path 44, and then is introduced into the dilution box 50.

  On the other hand, in the hydrogen supply system 18, a predetermined amount of hydrogen gas is supplied to the hydrogen supply path 52 under the action of the supply amount adjustment valve 54. This hydrogen gas is supplied to the hydrogen gas inlet communication hole 42 a of the fuel cell stack 14. The hydrogen gas supplied into the fuel cell stack 14 is supplied to the anode electrode 26 by moving along the fuel gas flow path 36 of each fuel cell 12.

  Hydrogen gas discharged to the hydrogen gas outlet communication hole 42 b (hereinafter also referred to as anode off gas) is sucked from the anode off gas discharge path 58 through the anode off gas circulation path 62 to the ejector 56. Therefore, the anode off gas is supplied again to the fuel cell stack 14 as a fuel gas. Therefore, the air supplied to the cathode electrode 24 and the hydrogen gas supplied to the anode electrode 26 react electrochemically to generate power.

  On the other hand, impurities tend to accumulate in the hydrogen gas circulating through the anode off-gas circulation path 62. For this reason, the hydrogen gas mixed with impurities is periodically discharged under the opening action of the hydrogen discharge valve 60.

  A cooling medium is supplied from a cooling medium system (not shown) to a cooling medium flow path 38 formed between the fuel cells 12 of the fuel cell stack 14. The cooling medium moves along the cooling medium flow path 38 to cool the fuel cell 12, and then is discharged outside and circulated and supplied.

  Next, the stopping method according to the first embodiment will be described with reference to the flowchart shown in FIG. 2 and the timing chart shown in FIG.

  First, when the operation of the fuel cell stack 14 is stopped (step S1), the process proceeds to step S2, and the supply amount adjusting valve 54 is closed.

  In step S3, the air supply system 16 is driven, scavenging air is supplied to the cathode side path (including the oxidant gas flow path 34) in the fuel cell stack 14, and cathode scavenging is performed.

  Furthermore, it progresses to step S4 and the resistance value output by the ground fault sensor 68 and the ground fault judgment value R0 memorize | stored beforehand by the control part 20 are compared. Although not shown, the ground fault sensor 68 detects whether or not the generated water discharged from the oxidant gas flow path 34 may cause the fuel cell stack 14 to ground through the gas-liquid separator. Similarly, it is detected whether or not the generated water discharged from the fuel gas flow path 36 may cause the fuel cell stack 14 to ground through a gas-liquid separator (not shown).

  Here, as shown in FIG. 3, the insulation resistance R rises because the stagnant water is removed by the scavenging of the cathode (see the broken line in FIG. 3), and an insulation resistance value higher than the ground fault determination value R0 is obtained. . On the other hand, in a state where a liquid junction is likely to occur, sufficient insulation recovery has not been performed, and the insulation resistance R maintains a value lower than the ground fault determination value R0.

  Therefore, when a state in which the insulation resistance R is lower than the ground fault determination value R0 is induced on either the cathode side or the anode side (YES in step S5), the process proceeds to step S6, and the cathode side or anode side A scavenging process is performed. The cathode scavenging process is the same as the cathode scavenging described above.

  On the other hand, in the scavenging process on the anode side, the on-off valve 66 is opened as shown in FIG. For this reason, the scavenging air supplied from the air supply system 16 to the air supply path 44 is introduced into the hydrogen supply path 52 through the bypass path 64. As a result, in the fuel cell stack 14, scavenging air is introduced from the hydrogen gas inlet communication hole 42 a, scavenging of the anode system (including the fuel gas flow path 36) is performed, and the hydrogen discharge valve 60 is discharged under the opening action. The

  As described above, when the scavenging on the cathode side or the anode side ends, the fuel cell system 10 stops (step S7). In step S5, when the insulation resistance R is greater than or equal to the ground fault determination value R0 (NO in step S5), the process is terminated because there is no possibility of a ground fault.

  In this case, in the first embodiment, after the operation of the fuel cell stack 14 is stopped, the scavenging means (the air supply system 16, the bypass path 64, and the on-off valve 66 is changed based on the insulation resistance R measured by the ground fault sensor 68. In this case, at least one of the cathode side and the anode side can be scavenged.

  At that time, it is possible to perform scavenging via the scavenging means regardless of whether the pole where the ground fault has occurred is on the cathode side or the anode side. As a result, it is possible to reliably detect a portion where a ground fault occurs in the fuel cell stack 14 and perform an efficient and economical scavenging process with a simple process.

  FIG. 4 is a schematic configuration diagram of a fuel cell system 80 according to the second embodiment of the present invention. Note that the same components as those of the fuel cell system 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The fuel cell stack 14 is the same as that of the first embodiment, but the configuration will be further described in detail. As shown in FIG. 5, end plates 86a and 86b are disposed at both ends of each fuel cell 12 in the stacking direction via insulating plates 84a and 84b for accommodating terminal plates 82a and 82b.

  A flow path member, for example, a humidifier 46 is connected to the end plate 86a. Note that a gas-liquid separator or the like is used as the flow path member in place of the humidifier 46.

  As shown in FIG. 6, the fuel cell 12 has a vertically long shape, and an air inlet communication hole 40 a and a hydrogen gas inlet communication hole 42 a are formed at the upper side end in the long side direction (arrow C direction). . A hydrogen gas outlet communication hole 42 b and an air outlet communication hole 40 b are formed at the lower side end portion of the fuel cell 12 in the long side direction.

  A coolant supply passage 43a is formed at one end in the short side direction of the fuel cell 12, and a coolant discharge communication hole 43b is formed at the other end portion in the short side direction.

  As shown in FIG. 5, the output terminals 90a and 90b protrude from the terminal plates 82a and 82b downward in the stacking direction, respectively. As shown in FIG. 7, a cathode inlet detection electrode 92a exposed to the air inlet communication hole 40a, a cathode outlet detection electrode 92b exposed to the air outlet communication hole 40b, An anode inlet detection electrode 94a exposed to the hydrogen gas inlet communication hole 42a and an anode outlet detection electrode 94b exposed to the hydrogen gas outlet communication hole 42b are installed.

  The cathode inlet detection electrode 92a is connected to the cathode inlet ammeter 96a, the cathode outlet detection electrode 92b is connected to the cathode outlet ammeter 96b, the anode inlet detection electrode 94a is connected to the anode inlet ammeter 98a, and the anode outlet The detection electrode 94b is connected to the anode outlet ammeter 98b.

  As shown in FIG. 5, the cathode inlet ammeter 96a and the cathode outlet ammeter 96b are connected to an output terminal 90b provided on the positive side terminal plate 82b. Although not shown, the anode inlet ammeter 98a and the anode outlet ammeter 98b are similarly connected to the output terminal 90b of the terminal plate 82b.

  The cathode inlet ammeter 96a, the cathode outlet ammeter 96b, the anode inlet ammeter 98a, and the anode outlet ammeter 98b output the measured current signal to the controller 20, and the controller 20 is connected to at least one of It has a function as the ground fault detection unit 100 that determines whether or not a fault has occurred.

  As shown in FIG. 4, a gas-liquid separator 88 and an on-off valve 89 are disposed in the anode off gas discharge path 58.

  Next, a method of stopping the fuel cell system 80 configured as described above will be described below along the flowchart shown in FIG. The detailed description of the same steps as the stopping method according to the first embodiment will be omitted.

  When the operation of the fuel cell stack 14 is stopped (step S101), the supply amount adjusting valve 54 is closed (step S102), and then scavenging air is supplied to perform cathode scavenging (step S103).

  Subsequently, it progresses to step S104 and an electric current detection process is performed. In this current detection process, the cathode inlet ammeter 96a, the cathode outlet ammeter 96b, the anode inlet ammeter 98a, and the anode outlet ammeter 98b are respectively used as an air inlet communication hole 40a, an air outlet communication hole 40b, and a hydrogen gas inlet communication hole. 42a and the hydrogen gas outlet communication hole 42b and the water connection in the cell surface are detected.

  In step S105, it is determined that the detected current value (cathode side current value) by at least one of the cathode inlet ammeter 96a and the cathode outlet ammeter 96b exceeds a determination value that is a threshold for ground fault determination. (YES in step S105), the process proceeds to step S106, the scavenging air is supplied, and the scavenging process on the cathode side is performed. This is because the current value is small if a ground fault has not occurred through the water in the communication hole, whereas the current value exceeds the determination value if a ground fault has occurred.

  Further, in step S107, it is determined whether or not the current value (anode-side current value) measured by at least one of the anode inlet ammeter 98a and the anode outlet ammeter 98b exceeds the determination value. If it is determined that one of the detected current values exceeds the determination value (YES in step S107), the process proceeds to step S108 where scavenging air is supplied and the anode-side scavenging process is performed. .

  Note that the steps S107 and S108 may be performed simultaneously with or before the steps S105 and S106. The above processing is completed, and the fuel cell system 80 is stopped (step S109).

  In this case, in the second embodiment, by measuring each current value between the cathode inlet detection electrode 92a, the cathode outlet detection electrode 92b, the anode inlet detection electrode 94a, the anode outlet detection electrode 94b, and the output terminal 90b, It is detected whether or not a ground fault occurs in each of the air inlet communication hole 40a, the air outlet communication hole 40b, the hydrogen gas inlet communication hole 42a, and the hydrogen gas outlet communication hole 42b.

  Therefore, the location where the ground fault occurs can be detected accurately and easily, and scavenging air can be supplied only to the pole side where the ground fault occurs. Thereby, it is possible to detect the site where the ground fault occurs in the fuel cell 12 with a simple configuration and process, and to perform the scavenging process efficiently and economically.

  In the second embodiment, the current value is detected to detect whether or not a ground fault has occurred. However, the present invention is not limited to this. For example, the presence or absence of occurrence of a ground fault may be detected by detecting a voltage value.

DESCRIPTION OF SYMBOLS 10, 80 ... Fuel cell system 12 ... Fuel cell 14 ... Fuel cell stack 16 ... Air supply system 18 ... Hydrogen supply system 20 ... Control part 22 ... Solid polymer electrolyte membrane 24 ... Cathode electrode 26 ... Anode electrode 34 ... Oxidant gas Flow path 36 ... Fuel gas flow path 38 ... Cooling medium flow path 44 ... Air supply path 46 ... Humidifier 48 ... Cathode off-gas discharge path 52 ... Hydrogen supply path 56 ... Ejector 58 ... Anode off-gas discharge path 68 ... Ground fault sensor 86a, 86b ... End plates 90a, 90b ... Output terminal 92a ... Cathode inlet detection electrode 92b ... Cathode outlet detection electrode 94a ... Anode inlet detection electrode 94b ... Anode outlet detection electrode 96a ... Cathode inlet ammeter 96b ... Cathode outlet ammeter 98a ... Anode inlet Ammeter 98b ... Anode outlet ammeter 100 ... Ground fault detector

Claims (4)

Laminating a plurality of fuel cells having an electrolyte membrane / electrode structure in which a cathode electrode and an anode electrode are provided on both sides of the electrolyte membrane, and an oxidant gas supplied to the cathode side of the fuel cell and an anode side of the fuel cell A fuel cell system for generating electricity by an electrochemical reaction of fuel gas supplied to
An oxidant gas communication hole through which the oxidant gas flows in the stacking direction of the fuel cell;
Fuel gas communication holes for flowing the fuel gas in the stacking direction;
A detection electrode disposed in the oxidant gas communication hole and the fuel gas communication hole;
A ground fault detector that determines whether or not a ground fault has occurred by measuring a voltage or current between the output terminal of the fuel cell and the detection electrode;
Scavenging means for supplying scavenging air to the cathode side and the anode side;
A fuel cell system comprising: Laminating a plurality of fuel cells having an electrolyte membrane / electrode structure in which a cathode electrode and an anode electrode are provided on both sides of the electrolyte membrane, and an oxidant gas supplied to the cathode side of the fuel cell and an anode side of the fuel cell A method for stopping a fuel cell system that generates electricity by an electrochemical reaction of a fuel gas supplied to
After stopping operation, measuring the insulation resistance with a ground fault sensor;
When it is determined that a ground fault has occurred on either the cathode side or the anode side based on the measured insulation resistance, scavenging air is supplied to the cathode side and the anode side Scavenging means capable of scavenging at least one of the polar sides with the scavenging air;
A method for stopping a fuel cell system, comprising: The method according to claim 2, wherein after scavenging the one pole side, determining whether or not a ground fault has occurred on the other pole side of the cathode side or the anode side;
Scavenging the other pole side with the scavenging air when it is determined that a ground fault has occurred on the other pole side; and
A method for stopping the fuel cell system. Laminating a plurality of fuel cells having an electrolyte membrane / electrode structure in which a cathode electrode and an anode electrode are provided on both sides of the electrolyte membrane, and an oxidant gas supplied to the cathode side of the fuel cell and an anode side of the fuel cell A method for stopping a fuel cell system that generates electricity by an electrochemical reaction of a fuel gas supplied to
An oxidant gas communication hole for flowing the oxidant gas in the stacking direction of the fuel cell, a detection electrode disposed in the fuel gas communication hole for flowing the fuel gas in the stacking direction, and an output terminal of the fuel cell Measuring the voltage or current between
When it is determined based on the measured voltage or current that a ground fault has occurred on either the cathode side or the anode side, scavenging air is supplied to the cathode side and the anode side. Scavenging means capable of scavenging the one pole side with the scavenging air; and
A method for stopping a fuel cell system, comprising:

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