JP6023403B2 - Fuel cell system and its operation stop method - Google Patents

Description

  The present invention provides a fuel cell having an electrolyte membrane / electrode structure in which a cathode electrode and an anode electrode are provided on both sides of an electrolyte membrane, an oxidant gas supply device for supplying an oxidant gas to the cathode side of the fuel cell, BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell system including a fuel gas supply device that supplies fuel gas to the anode side of the fuel cell, and an operation stop method thereof.

  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 during power generation, and when power generation is stopped, the generated water tends to stay on the downstream side of the oxidant gas channel and the fuel gas channel. When the fuel cell is stopped, when scavenging with air is performed on the oxidant gas flow path and the fuel gas flow path, the cathode side electrode is deteriorated due to the high potential at the start-up, particularly at the downstream side of the oxidant gas flow path. There is a problem of being triggered.

  Specifically, as shown in FIG. 10, the electrolyte membrane / electrode structure 4 in which the solid polymer electrolyte membrane 1 is sandwiched between the cathode electrode 2 and the anode electrode 3 has an oxidant gas flow to the cathode electrode 2 side. While a passage 5 is provided, a fuel gas passage 6 is provided on the anode electrode 3 side. When power generation is stopped, scavenging with air is performed in the oxidant gas passage 5 and the fuel gas passage 6.

  Therefore, when the oxidant gas (air) is supplied from the upstream side to the downstream side of the oxidant gas flow path 5, while the fuel gas (hydrogen gas) is supplied from the upstream side to the downstream side of the fuel gas flow path 6. , Potential behavior occurs in the order of reaction A, reaction B, reaction C and reaction D.

That is, on the upstream side of the fuel gas flow path 6, by supplying the fuel gas, a reaction A of H ₂ → 2H ⁺ + 2e ⁻ is induced, and this 2H ⁺ passes through the electrolyte membrane / electrode structure 4. And move to the oxidant gas flow path 5 side. In the oxidant gas flow path 5, the oxidant gas is supplied, and the reaction B of 1 / 2O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O occurs.

Downstream of the oxidizing gas channel 5, the water _{remaining, H 2 O → 1 / 2O} 2 + 2H + + 2e - and _{H 2 O + 1 / 2C (} C electrode catalyst layer) → 1 / _2CO 2 + 2H ⁺ + 2e ^- reaction C is induced. On the other hand, on the downstream side of the fuel gas channel 6, a reaction D of 1 / 2O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O occurs due to 2H ⁺ permeating from the downstream side of the oxidant gas channel 5. Reaction C is a rate-determining step, and all the reactions A to D are promoted by increasing the water content, and a high potential is generated.

  Accordingly, platinum is eluted from the cathode electrode 2, and the eluted platinum is reduced in the solid polymer electrolyte membrane 1 to return to the metal, thereby forming a platinum band. For this reason, when hydrogen molecules and oxygen molecules react with each other through the solid polymer electrolyte membrane 1 on the platinum band, for example, hydroxy radicals (OH radicals) are generated, and the solid polymer electrolyte membrane 1 is deteriorated. There is a problem of making it.

  The OH radical reaction is generated by a reaction between hydrogen molecules and oxygen molecules on the catalyst. In addition to the platinum band, for example, hydrogen molecules that have passed through the membrane from the anode side gas line system are transferred to the cathode electrode. Some of them are generated by reacting with oxygen molecules. In some cases, oxygen molecules that permeate from the cathode gas line system react with hydrogen molecules in the anode electrode.

  Therefore, in order to suppress this kind of OH radical reaction, for example, a system disclosed in Patent Document 1 is known. In this system, as shown in FIG. 11, an anode flow path 2a for guiding hydrogen fuel to flow adjacent to the anode catalyst 1a is in fluid communication with the anode catalyst 1a and is connected to the cathode catalyst 4a of the fuel cell 3a. A cathode channel 5a for guiding the oxidant to flow adjacently is in fluid communication with the cathode catalyst 4a.

  The hydrogen fuel is transferred between the anode channel 2a and the cathode channel 5a. Whenever the fuel cell 3a receives and stores hydrogen during operation of the fuel cell 3a and the fuel cell 3a is shut down, the hydrogen reservoir 6a is connected to the anode flow path to release the hydrogen to the fuel cell 3a. Mounted in fluid communication with 2a.

Special table 2007-534108 gazette

  However, in Patent Document 1 described above, when the operation of the fuel cell 3a is stopped, hydrogen is supplied to the anode channel 2a and the cathode channel 5a. For this reason, hydrogen is consumed wastefully, which is uneconomical, and it is necessary to dilute the hydrogen supplied at the time of the operation stop and release it to the atmosphere. For this reason, there exists a problem that a dilution structure becomes large and complicated.

  The present invention solves this type of problem, and can reduce the oxygen concentration distribution in the electrode surface and suppress the deterioration of the electrolyte membrane as much as possible with an economical configuration and process. It is an object of the present invention to provide a possible fuel cell system and a method for stopping the fuel cell system.

  The present invention provides a fuel cell having an electrolyte membrane / electrode structure in which a cathode electrode and an anode electrode are provided on both sides of an electrolyte membrane, an oxidant gas supply device for supplying an oxidant gas to the cathode side of the fuel cell, The present invention relates to a fuel cell system including a fuel gas supply device that supplies fuel gas to an anode side of the fuel cell, and an operation stop method thereof.

The shutdown method, while supplying an oxygen-containing gas to the fuel cell from the oxidant gas supply pipe constituting the oxidizing gas supply device, the fuel gas to the fuel cell from the fuel gas supply pipe constituting the fuel gas supplying device To generate power and discharge the oxidant gas from the fuel cell to an oxidant gas discharge pipe constituting the oxidant gas supply device, while the fuel cell constitutes the fuel gas supply device a generator step of discharging the fuel gas to the gas discharge pipe, with the operation of the prior SL fuel cell after being stopped, to stop the supply of the oxidant gas by the oxidizing gas supplying device, by the fuel gas supply device An atmosphere release step of stopping the supply of the fuel gas and then opening the oxidant gas discharge pipe and the oxidant gas supply pipe to the atmosphere.

  In this operation stop method, it is preferable that the oxidant gas supply pipe is opened to the atmosphere by opening an on-off valve provided in the oxidant gas supply pipe.

  Furthermore, in this operation stop method, it is preferable that the oxidant gas discharge pipe communicates with the oxidant gas supply pipe through the bypass flow path to open the oxidant gas supply pipe to the atmosphere.

  Furthermore, in this fuel cell system, the fuel gas supply device includes a fuel gas supply pipe for supplying fuel gas to the fuel cell, and a fuel gas discharge pipe for discharging the fuel gas from the fuel cell.

The oxidant gas supply device includes an oxidant gas supply pipe for supplying an oxidant gas to the fuel cell, and discharges the oxidant gas from the fuel cell, and after the operation of the fuel cell is stopped, An oxidant gas discharge pipe that is open to the atmosphere, and after the operation of the fuel cell is stopped , the supply of the oxidant gas by the oxidant gas supply device is stopped, and the fuel gas by the fuel gas supply device , And thereafter, the oxidant gas discharge pipe and the oxidant gas supply pipe are opened to the atmosphere.

  Furthermore, in this fuel cell system, it is preferable that the air release means includes an on-off valve disposed in the oxidant gas supply pipe.

  Furthermore, in this fuel cell system, it is preferable that the air release means includes a bypass flow path that connects the oxidant gas discharge pipe and the oxidant gas supply pipe.

  In the present invention, after the operation of the fuel cell is stopped, the oxidant gas discharge pipe and the oxidant gas supply pipe are opened to the atmosphere. For this reason, it is possible to disperse the membrane deterioration reaction of the electrolyte membrane between the inlet side and the outlet side of the fuel cell. In addition, it is possible to suppress deterioration on the downstream side with a large water content. Therefore, the oxygen concentration distribution in the electrode surface can be reduced with a simple and economical configuration and process, and deterioration of the electrolyte membrane can be suppressed as much as possible.

1 is an explanatory diagram of a schematic configuration of a fuel cell system according to a first embodiment of the present invention. It is a flowchart explaining the operation stop method which concerns on 1st Embodiment by the said fuel cell system. FIG. 6 is a relationship diagram of oxygen concentration and film deterioration amount in an oxidant gas flow path when the operation stop method is performed. FIG. 6 is a relationship diagram of oxygen concentration and film deterioration amount in the oxidant gas flow path when a conventional method is performed. It is a schematic structure explanatory drawing of the fuel cell system concerning the 2nd Embodiment of this invention. It is a flowchart explaining the operation stop method which concerns on 2nd Embodiment by the said fuel cell system. FIG. 6 is a relationship diagram of oxygen concentration and film deterioration amount in the oxidant gas flow path when the operation stop method is performed. It is schematic structure explanatory drawing of the fuel cell system which concerns on the 3rd Embodiment of this invention. It is a flowchart explaining the operation stop method which concerns on 3rd Embodiment by the said fuel cell system. It is explanatory drawing of the electric potential behavior inside the fuel cell at the time of starting. 1 is a schematic explanatory diagram of a system disclosed in Patent Document 1. FIG.

  As shown in FIG. 1, the fuel cell system 10 according to the first embodiment of the present invention constitutes, for example, an in-vehicle fuel cell system and is mounted on a fuel cell electric vehicle (not shown).

  The fuel cell system 10 includes a fuel cell 12, an oxidant gas supply device 14 that supplies an oxidant gas to the fuel cell 12, a fuel gas supply device 16 that supplies a fuel gas to the fuel cell 12, and the fuel cell. 12 is provided with a cooling medium supply device (not shown) for supplying a cooling medium to 12 and a controller 18 for controlling the entire fuel cell system 10.

  The fuel cell 12 includes, for example, an electrolyte membrane / electrode structure (MEA) 26 in which a solid polymer electrolyte membrane 20 in which a thin film of perfluorosulfonic acid is impregnated with water is sandwiched between a cathode electrode 22 and an anode electrode 24.

  The cathode electrode 22 and the anode electrode 24 have a gas diffusion layer made of carbon paper or the like, and porous carbon particles having platinum alloy (or Ru or the like) supported 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 20.

  The fuel cell 12 includes an oxidant gas channel 28 for supplying an oxidant gas, for example, an oxygen-containing gas (hereinafter also referred to as air), along the cathode electrode 22 of the electrolyte membrane / electrode structure 26, and the electrolyte. A fuel gas flow path 30 for supplying a fuel gas, for example, a hydrogen-containing gas (hereinafter also referred to as hydrogen gas), is provided along the anode electrode 24 of the membrane / electrode structure 26.

  An oxidant gas inlet communication hole 32 a communicates with the inlet side of the oxidant gas flow path 28, and an oxidant gas outlet communication hole 32 b communicates with the outlet side of the oxidant gas flow path 28. A fuel gas inlet communication hole 34 a communicates with the inlet side of the fuel gas flow path 30, and a fuel gas outlet communication hole 34 b communicates with the outlet side of the fuel gas flow path 30.

  The oxidant gas passage 28 and the fuel gas passage 30 are each formed by a separator (not shown), and a plurality of fuel cells 12 are stacked to constitute a fuel cell stack.

  The oxidant gas supply device 14 includes an air pump (or supercharger) 36 that compresses and supplies air from the atmosphere, and the air pump 36 is disposed in an oxidant gas supply pipe 38. The oxidant gas supply pipe 38 communicates with the oxidant gas inlet communication hole 32a of the fuel cell 12, and the branch pipe 40 branches near the oxidant gas inlet communication hole 32a. The branch pipe 40 is provided with an on-off valve 42 and constitutes an air release means 43.

  The oxidant gas supply device 14 includes an oxidant gas discharge pipe 44 that communicates with the oxidant gas outlet communication hole 32 b of the fuel cell 12. A pressure holding valve 46 is disposed in the oxidant gas discharge pipe 44. The pressure holding valve 46 is opened when the operation of the fuel cell 12 is stopped (during soak), thereby opening the oxidant gas discharge pipe 44 to atmospheric pressure.

The fuel gas supply device 16 includes a hydrogen tank (H ₂ tank) 48 that stores high-pressure hydrogen. The hydrogen tank 48 communicates with the fuel gas inlet communication hole 34 a of the fuel cell 12 through the fuel gas supply pipe 50. An ejector 52 is provided in the fuel gas supply pipe 50.

  The fuel gas supply device 16 includes a fuel gas discharge pipe 54 that communicates with the fuel gas outlet communication hole 34 b of the fuel cell 12. A purge valve 56 is disposed in the fuel gas discharge pipe 54, and a circulation pipe 58 is connected to the upstream side of the purge valve 56 and the ejector 52.

  The ejector 52 supplies hydrogen gas supplied from the hydrogen tank 48 to the fuel cell 12 through the fuel gas supply pipe 50 and circulates exhaust gas containing unused hydrogen gas that has not been used in the fuel cell 12. The air is sucked from the pipe 58 and supplied again to the fuel cell 12 as fuel gas.

  The operation of the fuel cell system 10 configured as described above will be described below along the flowchart shown in FIG. 2 in relation to the operation stop method according to the first embodiment.

  First, the fuel cell system 10 is normally operated (step S1). During normal operation, as shown in FIG. 1, air is sent to the oxidant gas supply pipe 38 via the air pump 36 that constitutes the oxidant gas supply device 14. The air is supplied to the cathode electrode 22 by moving along the oxidant gas flow path 28 from the oxidant gas inlet communication hole 32 a of the fuel cell 12.

  The used air is discharged from the oxidant gas outlet communication hole 32b to the oxidant gas discharge pipe 44 and discharged to the outside while the supply pressure is maintained by the pressure holding valve 46.

  On the other hand, in the fuel gas supply device 16, hydrogen gas is supplied from the hydrogen tank 48 to the fuel gas supply pipe 50. The hydrogen gas is supplied to the fuel gas inlet communication hole 34 a of the fuel cell 12 through the fuel gas supply pipe 50. The hydrogen gas supplied into the fuel cell 12 is supplied to the anode electrode 24 by moving along the fuel gas flow path 30.

  Used (including unreacted hydrogen gas) hydrogen gas (hereinafter also referred to as hydrogen off-gas) is discharged from the fuel gas outlet communication hole 34b to the fuel gas discharge pipe 54. This hydrogen off-gas is sucked into the ejector 52 through the circulation pipe 58 and is supplied again to the fuel cell 12 as fuel gas. Therefore, oxygen in the air supplied to the cathode electrode 22 and hydrogen gas supplied to the anode electrode 24 react electrochemically to generate power.

  On the other hand, impurities tend to accumulate in the hydrogen off-gas circulating through the circulation pipe 58. For this reason, the hydrogen off gas mixed with impurities is discharged when the purge valve 56 is opened.

  Next, when the operation of the fuel cell 12 is stopped (YES in step S2), the supply of the oxidant gas by the oxidant gas supply device 14 is stopped and the supply of the fuel gas by the fuel gas supply device 16 is stopped. Is done.

  Further, the pressure holding valve 46 provided in the oxidant gas supply device 14 is opened to stop the pressure holding (step S3). And it progresses to step S4 and the on-off valve 42 which comprises the air release means 43 is open | released. Accordingly, external air is sucked from the branch pipe 40, and the external air is introduced from the oxidant gas supply pipe 38 to the oxidant gas inlet communication hole 32 a of the fuel cell 12.

  On the other hand, the holding valve 46 is opened in the oxidant gas discharge pipe 44. Therefore, external air is introduced into the oxidant gas discharge pipe 44, and this external air is introduced from the oxidant gas outlet communication hole 32 b of the fuel cell 12.

  Therefore, in the fuel cell 12, the oxygen concentration on the inlet side and the outlet side is higher than the oxygen concentration in the central portion, and the oxygen concentration shown in FIG. 3 is obtained in the oxidant gas flow path 28 (Ca path). Further, following the oxygen concentration, the reaction amount of oxygen and hydrogen, that is, the film deterioration amount is substantially equalized on the inlet side and the outlet side.

  On the other hand, in the conventional system in which the outside air is introduced only from the oxidant gas outlet communication hole 32b when the operation is stopped without providing the atmosphere opening means 43, as shown in FIG. 4, the outlet of the oxidant gas flow path 28 is provided. The oxygen concentration and the film deterioration amount on the side are considerably larger than those of other parts. For this reason, in the conventional method (only the outlet is opened), the membrane degradation of the solid polymer electrolyte membrane 20 becomes significant.

  In this case, in the first embodiment, concentration of film deterioration of the solid polymer electrolyte membrane 20 can be prevented. That is, as can be understood from FIGS. 3 and 4, the reaction amount of hydrogen and oxygen in the fuel cell 12 as a whole is not different from that in the conventional method, but the bias in the oxygen concentration is reduced, so that the solid polymer electrolyte is reduced. The film deterioration reaction of the film 20 can be dispersed. Thereby, it is possible to reduce the oxygen concentration distribution in the electrode surface with a simple and economical configuration and process, and to suppress deterioration of the solid polymer electrolyte membrane 20 as much as possible. can get.

  As shown in FIG. 2, after the on-off valve 42 is opened for a predetermined time, the operation shifts to the soak (operation stop state) of the fuel cell 12 (step S5). Thereby, the operation stop process of the fuel cell system 10 is completed.

  FIG. 5 is a schematic configuration explanatory diagram of a fuel cell system 70 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 system 70 includes an oxidant gas supply device 72. The oxidant gas supply device 72 includes a bypass passage 74 that allows the oxidant gas supply pipe 38 and the oxidant gas discharge pipe 44 to communicate with each other, and an on-off valve 76 is disposed in the bypass passage 74. The bypass passage 74 and the opening / closing valve 76 constitute an air release means 77.

  A method of stopping the operation of the fuel cell system 70 configured as described above will be described below along the flowchart shown in FIG.

  The fuel cell system 70 performs normal driving (step S101), and determines whether the fuel cell 12 is in an idle state (step S102). The idle state refers to, for example, a state where the ignition switch is turned on and the electric load of the vehicle travel motor is below a predetermined value for a predetermined time. For example, a state in which the rotational speed of the motor for driving is a predetermined low speed rotational speed including zero, a state in which a regenerative control force is being generated when the fuel cell electric vehicle is decelerated, and a traveling that automatically keeps the speed constant. Applicable status.

  If it is determined that the engine is in the idle state (YES in step S102), the process proceeds to step S103, and idle stop control is performed. In this idle stop control, fuel gas is circulated to the anode side, and a predetermined amount of oxidant gas, which is less than the amount of oxidant gas supplied during normal power generation to obtain power that can be traveled, is supplied to the cathode side for power generation. At the same time, the generated current is discharged by supplying current to the external load. For this reason, in the fuel cell 12, the electrochemical reaction between hydrogen and oxygen is performed, and the oxidant off-gas discharged from the oxidant gas outlet communication hole 32b to the oxidant gas discharge pipe 44 has a low oxygen concentration. The gas is filled with nitrogen gas.

  Further, it is determined that the fuel cell 12 is stopped (YES in step S104), and after the reaction gas supply stop and the pressure holding stop are performed (step S105), the process proceeds to step S106. In this step S106, the on-off valve 76 is opened, and the gas having a low oxygen concentration remaining in the oxidant gas discharge pipe 44 passes through the oxidant gas supply pipe 38 from the bypass flow path 74 and passes through the oxidant gas supply pipe 38. It is supplied to the inlet communication hole 32a.

  In this case, in the second embodiment, a low oxygen concentration gas remains in the oxidant gas discharge pipe 44, and this low oxygen concentration gas passes through the oxidant gas outlet communication hole 32 b of the fuel cell 12. The oxidant gas inlet communication hole 32a is supplied via the bypass channel 74.

  Therefore, in the oxidant gas flow path 28, as shown in FIG. 7, the oxygen concentration on the inlet side and the outlet side is reduced as compared with the normal oxygen concentration. The amount can be reduced as a whole.

  Moreover, compared with the conventional example in which only the oxidant gas outlet communication hole 32b is opened to the atmosphere, the concentration of deterioration of the solid polymer electrolyte membrane 20 is satisfactorily suppressed. Thereby, the effect that deterioration of the solid polymer electrolyte membrane 20 is suppressed as much as possible is obtained.

  FIG. 8 is a schematic configuration explanatory view of a fuel cell system 90 according to the third embodiment of the present invention. The same components as those of the fuel cell system 10 according to the first embodiment and the fuel cell system 70 according to the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The fuel cell system 90 includes an oxidant gas supply device 92, and the oxidant gas supply device 92 uses air release means 43 and 77 in combination.

  The operation stopping method by the fuel cell system 90 configured as described above is performed in accordance with the flowchart shown in FIG.

  In the third embodiment, substantially the same as in the second embodiment, after step S201 to step S206 are performed, the process proceeds to step S207. In step S207, the open / close valve 42 constituting the atmosphere release means 43 is opened, so that external air is introduced into the oxidant gas inlet communication hole 32a of the fuel cell 12.

  That is, in the third embodiment, first, the open / close valve 76 constituting the atmosphere opening means 77 is opened, so that the low oxygen concentration nitrogen gas remaining in the oxidant gas discharge pipe 44 is passed through the bypass flow path 74. To the oxidant gas inlet communication hole 32a of the fuel cell 12. Next, outside air is introduced into the oxidant gas inlet communication hole 32 a under the opening action of the on-off valve 42.

  For this reason, in the fuel cell 12, after the oxygen concentration at the inlet and the outlet is lowered to reduce the oxygen concentration distribution in the electrode surface, both the inlet side and the outlet side are opened to the atmosphere. Thereby, in 3rd Embodiment, the effect similar to said 1st and 2nd embodiment is acquired.

DESCRIPTION OF SYMBOLS 10, 70, 90 ... Fuel cell system 12 ... Fuel cell 14 ... Oxidant gas supply device 16 ... Fuel gas supply device 18 ... Controller 20 ... Solid polymer electrolyte membrane 22 ... Cathode electrode 24 ... Anode electrode 26 ... Electrolyte membrane electrode Structure 28 ... Oxidant gas flow path 30 ... Fuel gas flow path 32a ... Oxidant gas inlet communication hole 32b ... Oxidant gas outlet communication hole 34a ... Fuel gas inlet communication hole 34b ... Fuel gas outlet communication hole 36 ... Air pump 38 ... Oxidant gas supply pipe 40 ... Branch pipes 42, 76 ... Open / close valve 43 ... Air release means 44 ... Oxidant gas discharge pipe 46 ... Holding pressure valve 48 ... Hydrogen tank 50 ... Fuel gas supply pipe 52 ... Ejector 54 ... Fuel gas discharge pipe 58 ... circulation piping 72, 92 ... oxidant gas supply device 74 ... bypass passage 77 ... air release means

Claims (6)

A fuel cell having an electrolyte membrane / electrode structure in which a cathode electrode and an anode electrode are provided on both sides of the electrolyte membrane;
An oxidant gas supply device for supplying an oxidant gas to the cathode side of the fuel cell;
A fuel gas supply device for supplying fuel gas to the anode side of the fuel cell;
A method for stopping operation of a fuel cell system comprising:
The oxidant gas is supplied to the fuel cell from an oxidant gas supply pipe constituting the oxidant gas supply apparatus, and the fuel gas is supplied to the fuel cell from a fuel gas supply pipe constituting the fuel gas supply apparatus. Power generation,
The oxidant gas is discharged from the fuel cell to an oxidant gas discharge pipe constituting the oxidant gas supply apparatus, and the fuel gas is discharged from the fuel cell to a fuel gas discharge pipe constituting the fuel gas supply apparatus. Power generation process,
After the operation of the fuel cell is stopped, the supply of the oxidant gas by the oxidant gas supply device is stopped, the supply of the fuel gas by the fuel gas supply device is stopped, and then the oxidant gas the discharge pipe and the oxidizing gas supply pipe is closed and the air release step for releasing to the atmosphere, and
In the air release step,
A method for stopping operation of a fuel cell system , comprising: opening an on-off valve disposed between the oxidant gas supply pipe and the atmosphere to open the oxidant gas supply pipe to the atmosphere . The operation stop method according to claim 1,
In the air release step,
By opening the on-off valve disposed between the oxidant gas supply pipe and the atmosphere, the oxidant gas supply pipe is opened to the atmosphere, and
The oxidant gas discharge pipe is communicated with the oxidant gas supply pipe via a bypass flow path in which another on-off valve is disposed, and the other on-off valve is opened to thereby supply the oxidant gas. A method for stopping operation of a fuel cell system, characterized in that piping is opened to the atmosphere .   3. The operation stop method according to claim 1, wherein the oxygen concentration at the inlet side and the outlet side is higher than the oxygen concentration at the central portion inside the fuel cell. 4. Method. 4. The operation stop method according to claim 3 , wherein the discharge is performed by supplying the generated current from the fuel cell to an external load before opening the bypass flow path. A fuel cell having an electrolyte membrane / electrode structure in which a cathode electrode and an anode electrode are provided on both sides of the electrolyte membrane;
An oxidant gas supply device for supplying an oxidant gas to the cathode side of the fuel cell;
A fuel gas supply device for supplying fuel gas to the anode side of the fuel cell;
A fuel cell system comprising:
The fuel gas supply device includes a fuel gas supply pipe for supplying the fuel gas to the fuel cell;
A fuel gas discharge pipe for discharging the fuel gas from the fuel cell;
With
The oxidant gas supply device includes an oxidant gas supply pipe for supplying the oxidant gas to the fuel cell;
Discharging the oxidant gas from the fuel cell, and after the operation of the fuel cell is stopped, an oxidant gas discharge pipe opened to the atmosphere;
After the operation of the fuel cell is stopped, the supply of the oxidant gas by the oxidant gas supply device is stopped, the supply of the fuel gas by the fuel gas supply device is stopped, and then the oxidant gas Air release means for opening the discharge pipe and the oxidant gas supply pipe to the atmosphere ,
The atmosphere opening means includes an on-off valve disposed between the oxidant gas supply pipe and the atmosphere, and the oxidant gas supply pipe is opened to the atmosphere by opening the on-off valve. A fuel cell system. The fuel cell system according to claim 5 , wherein
The air release means is
Opening the oxidant gas supply pipe to the atmosphere by opening the on-off valve disposed between the oxidant gas supply pipe and the atmosphere,
The oxidant gas supply pipe is provided with a bypass flow path in which another open / close valve is provided for communicating the oxidant gas discharge pipe and the oxidant gas supply pipe, and the other open / close valve is opened. Is opened to the atmosphere .

Images