Fuel cell system

Abstract

To prevent exhaust of high-concentration hydrogen in a fuel cell system.SOLUTION: A fuel cell system includes: a fuel cell; a cathode passage connected to a cathode of the fuel cell; air supply means provided on the cathode passage to supply air to the cathode; sealing means provided on the cathode passage to seal the cathode; and a controller controlling the state of the fuel cell. When it is determined that hydrogen is present in a predetermined amount or more in a cathode compartment of the fuel cell while the cathode is sealed by the sealing means, the controller exhausts gas from the cathode compartment by supplying air to the cathode using the air supply means.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fuel cell system, and more particularly to a fuel cell system mounted on an industrial vehicle. [Background technology]

[0002] Fuel cell systems generate electricity by electrochemically reacting hydrogen and oxygen via an electrolyte. For example, the amount of hydrogen and / or air supplied to the fuel cell is adjusted in response to demand from an external load, thereby generating the electricity required by the external load.

[0003] It is assumed that the fuel cell system operates according to a predetermined sequence. For example, in a start-up sequence, hydrogen is first supplied to the anode, and then air is supplied to the cathode. In a stop sequence, the supply of hydrogen / air is stopped, and an auxiliary power source such as a capacitor is charged. Patent Document 1 discloses a procedure in which, when starting up a fuel cell, gas remaining in at least one of the fuel gas flow path and the oxidant gas flow path is forcibly exhausted, and, when stopping the fuel cell, power is generated for a predetermined period of time with the supply of at least one of the fuel gas and the oxidant gas stopped. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-203222 A Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, a fuel cell system is expected to operate according to a predetermined sequence. However, the fuel cell system may operate outside of the predetermined sequence. For example, the fuel cell system may be mounted on an industrial vehicle such as a forklift. Generally, the industrial vehicle is started and stopped frequently. For this reason, the operator of the industrial vehicle may operate the fuel cell system outside of the predetermined sequence. For example, there may be a case where the main switch of the industrial vehicle is turned off in the middle of the start-up sequence.

[0006] If the fuel cell system is operated outside of a predetermined sequence, the hydrogen concentration in the FC (Fuel Cell) stack that constitutes the fuel cell system may remain high, which is undesirable since there is a risk of high-concentration hydrogen being exhausted.

[0007] It is an object of one aspect of the present invention to prevent the exhaust of high concentrations of hydrogen in a fuel cell system. [Means for solving the problem]

[0008] A fuel cell system according to one aspect of the present invention includes a fuel cell, a cathode flow path connected to a cathode of the fuel cell, an air supply means provided on the cathode flow path for supplying air to the cathode, a sealing means provided on the cathode flow path for sealing the cathode, and a controller for controlling a state of the fuel cell. When the controller determines that a predetermined amount or more of hydrogen is present in the cathode compartment of the fuel cell with the cathode sealed by the sealing means, the controller exhausts gas in the cathode compartment by supplying air to the cathode using the air supply means.

[0009] According to this configuration, even if hydrogen remains in the cathode compartment of the fuel cell due to an unexpected operation, the hydrogen in the cathode compartment is exhausted by supplying air to the cathode. In addition, by supplying air, the hydrogen remaining in the cathode compartment reacts with oxygen and turns into water. Therefore, the concentration of hydrogen exhausted from the fuel cell system in the next startup sequence is appropriately suppressed.

[0010] The controller may have a function for controlling a start-up sequence including a hydrogen supplying step for supplying hydrogen to the anode of the fuel cell, and an air supplying step for supplying air to the cathode of the fuel cell after the hydrogen supplying step. In this case, when an instruction to stop the fuel cell is received during the start-up sequence and before the air supplying step is completed, the controller performs the air supplying step to exhaust gas in the cathode compartment. With this configuration, hydrogen in the cathode compartment can be appropriately exhausted even if a stop instruction is given by the user during the start-up sequence.

[0011] The cathode flow path may include an air supply flow path that supplies air to the cathode and an exhaust flow path that exhausts cathode off-gas from the cathode compartment. In this case, the sealing means is realized by an air shutoff valve provided in the air supply flow path and an air pressure regulating valve provided in the exhaust flow path. Effect of the Invention

[0012] According to the above-described aspect, it is possible to prevent high-concentration hydrogen from being discharged in the fuel cell system. [Brief description of the drawings]

[0013] [Figure 1] 1 is a diagram showing an example of a fuel cell system according to an embodiment of the present invention. [Diagram 2] FIG. 4 is a diagram showing an example of an operation sequence of the fuel cell system. [Diagram 3] FIG. 2 is a diagram for explaining the hydrogen concentration in the FC stack. [Figure 4] 1 is a diagram for explaining a problem that occurs when a fuel cell system operates outside a predetermined sequence. [Diagram 5] 4 is a flowchart showing an example of the operation of the fuel cell system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Fig. 1 shows an example of a fuel cell system according to an embodiment of the present invention. The fuel cell system 1 according to the embodiment of the present invention includes an FC stack (fuel cell) 11. The FC stack 11 is formed by stacking a plurality of fuel cell cells. Furthermore, by connecting the plurality of fuel cell cells in series, the FC stack 11 can output a desired high voltage.

[0015] The fuel cell has an electrolyte membrane between the anode and the cathode. Hydrogen is supplied to the anode side, and air containing oxygen is supplied to the cathode side. As a result, the FC stack 11 generates electricity through an electrochemical reaction between hydrogen and oxygen, and water (hereinafter sometimes referred to as "produced water") is produced during the reaction. Therefore, a hydrogen supply flow path 21 for supplying hydrogen to the anode and an air supply flow path 41 for supplying air to the cathode are connected to the FC stack 11. Note that hydrogen is an example of a fuel gas, and air is an example of an oxidizing gas.

[0016] The hydrogen supply flow path 21 is a flow path for supplying hydrogen stored in the hydrogen tank 22 to the anode of the FC stack 11. The hydrogen supply flow path 21 is provided with a main valve 23, a regulator 24, and an injector 25. The main valve 23 allows or blocks the supply of hydrogen from the hydrogen tank 22 to the FC stack 11. The regulator 24 adjusts the pressure of the hydrogen gas supplied from the hydrogen tank 22 via the main valve 23. The injector 25 has an injector valve (not shown) built in, and supplies the required amount of hydrogen to the FC stack 11 by controlling this injector valve. The main valve 23, the regulator 24, and the injector 25 are controlled by a controller 81, which will be described later. The hydrogen supply flow path 21, the main valve 23, the regulator 24, and the injector 25 are an example of a hydrogen supply means for supplying hydrogen from the hydrogen tank 22 to the FC stack 11.

[0017] Furthermore, hydrogen supply flow path 21 is provided with a temperature sensor 26 and pressure sensors 27-29. Temperature sensor 26 detects the temperature in hydrogen supply flow path 21 between hydrogen tank 22 and main valve 23. Pressure sensor 27 detects the pressure of hydrogen gas supplied from hydrogen tank 22 via main valve 23. Pressure sensor 28 detects the pressure of hydrogen gas in hydrogen supply flow path 21 upstream of injector 25. Pressure sensor 29 detects the pressure of hydrogen gas in hydrogen supply flow path 21 downstream of injector 25. Values ​​detected by temperature sensor 26 and pressure sensors 27-29 are notified to controller 81, which will be described later.

[0018] The air supply flow path 41 is a flow path for supplying air in the atmosphere to the cathode of the FC stack 11. An air compressor 42 and an air shutoff valve 43 are provided in the air supply flow path 41. The air compressor 42 compresses air sucked from the atmosphere and supplies it to the FC stack 11 via the air supply flow path 41. The air shutoff valve 43 can cut off the supply of air to the FC stack 11. The air compressor 42 and the air shutoff valve 43 are controlled by a controller 81, which will be described later.

[0019] A circulation flow path 51 and an exhaust flow path 61 are connected to the FC stack 11. The circulation flow path 51 is provided to return hydrogen contained in the anode off-gas (gas exhausted from the anode compartment) discharged from the FC stack 11 to the hydrogen supply flow path 21. In addition, the exhaust flow path 61 is provided to discharge the cathode off-gas (gas exhausted from the cathode compartment) discharged from the FC stack 11 to the outside.

[0020] The circulation flow path 51 is provided with a gas-liquid separator 52 and a hydrogen circulation pump 53. The anode off-gas exhausted from the FC stack 11 contains hydrogen that remains without reacting with oxygen and water generated by an electrochemical reaction. The gas-liquid separator 52 separates the anode off-gas exhausted from the FC stack 11 into a gas and a liquid. At this time, most of the hydrogen in the anode off-gas is guided from the gas-liquid separator 52 to the hydrogen circulation pump 53. The hydrogen circulation pump 53 causes the hydrogen gas separated by the gas-liquid separator 52 to flow into the hydrogen supply flow path 21. The hydrogen circulation pump 53 is controlled by a controller 81, which will be described later.

[0021] The remaining anode off-gas is guided from the gas-liquid separator 52 to the diluter 63 via the exhaust drain valve 54. The anode off-gas guided to the diluter 63 contains water and hydrogen that was not completely extracted by the gas-liquid separator 52.

[0022] An air pressure regulating valve 62 is provided in the exhaust flow path 61. The air pressure regulating valve 62 adjusts the pressure of the cathode off-gas exhausted from the FC stack 11. Here, the air pressure regulating valve 62 is controlled by a controller 81, which will be described later. Then, the cathode off-gas, whose pressure has been adjusted by the air pressure regulating valve 62, is guided to the diluter 63. At this time, this cathode off-gas may be guided to the diluter 63 via a water storage tank 64.

[0023] The diluter 63 mixes the anode off-gas with the cathode off-gas. As a result, the hydrogen contained in the anode off-gas is diluted by using the cathode off-gas (i.e., air). In other words, the diluter 63 reduces the concentration of hydrogen exhausted from the fuel cell system 1. The water storage tank 64 temporarily stores water (i.e., produced water) generated in the FC stack 11. The produced water stored in the water storage tank 64 is drained via a drain coupler (not shown).

[0024] The air supply flow path 41 and the exhaust flow path 61 form a cathode flow path that connects to the cathode of the FC stack 11. The air shut valve 43 and the air pressure adjustment valve 62 form a sealing means that seals the cathode of the FC stack 11. When the air shut valve 43 and the air pressure adjustment valve 62 are controlled to be closed by the controller 81, the flow of gas between the cathode compartment of the FC stack 11 and the outside is blocked.

[0025] The fuel cell system 1 is equipped with a hydrogen sensor 71. The hydrogen sensor 71 detects hydrogen in the gas exhausted from the FC stack 11. The hydrogen sensor 71 also detects hydrogen leaking from the FC stack 11. Note that since hydrogen is lighter than air, the hydrogen sensor 71 is preferably disposed above the FC stack 11.

[0026] The controller 81 includes a processor and a memory, and controls the operation of the fuel cell system 1. Here, the controller 81 may control the operation of the fuel cell system 1 based on the temperature detected by the temperature sensor 26, the pressure detected by the pressure sensors 27-29, and the concentration detected by the hydrogen sensor 71. The controller 81 may also control the operation of the fuel cell system 1 in response to a request from the load of the fuel cell system 1. At this time, the controller 81 controls the main valve 23, the regulator 24, the injector 25, the air compressor 42, the air shutoff valve 43, the hydrogen circulation pump 53, the exhaust drain valve 54, and the air pressure adjustment valve 62 based on these parameters (sensor value, command value). The load is an electrical device that consumes the power generated by the fuel cell system 1, and includes a traveling motor when the fuel cell system 1 is mounted on an industrial vehicle, for example. Also, when the fuel cell system 1 is mounted on a forklift, the load includes a traveling motor and a loading motor.

[0027] 2 shows an example of an operation sequence of the fuel cell system 1. In this embodiment, the operation sequence of the fuel cell system 1 includes a start-up sequence, a power generation sequence, and a stop sequence. After the stop sequence ends, the fuel cell system 1 transitions to a standby state. In this embodiment, the fuel cell system 1 is assumed to be mounted on an industrial vehicle.

[0028] The start-up sequence includes a system check, a hydrogen filling process, and an air filling process. Then, in the standby state, when the main switch of the industrial vehicle is turned on, the controller 81 executes a system check.

[0029] If no errors occur during the system check, the controller 81 performs the hydrogen supplying process. At this time, the controller 81 controls the main valve 23, the regulator 24, and the injector 25 to start the supply of hydrogen from the hydrogen tank 22 to the FC stack 11. As a result, the hydrogen concentration in the anode compartment of the FC stack 11 increases.

[0030] Next, the controller 81 performs the air supplying step. At this time, the controller 81 controls the air compressor 42 and the air shutoff valve 43 to start supplying air to the FC stack 11. This increases the oxygen concentration in the cathode compartment of the FC stack 11. Then, when hydrogen is supplied to the anode and air (i.e., oxygen) is supplied to the cathode, the operation mode of the fuel cell system 1 transitions from the startup sequence to the power generation sequence.

[0031] If the air introduction process were to be carried out before the hydrogen introduction process in the start-up sequence, there is a risk that the power generation sequence would start at the point when air is supplied to the cathode if hydrogen remains in the FC stack 11. For this reason, the air introduction process is determined to be carried out after the hydrogen introduction process in the start-up sequence.

[0032] In the power generation sequence, the FC stack 11 is controlled to a power generation state or an idle state. For example, when the load requires power, the controller 81 sets the FC stack 11 to a power generation state by controlling the injector 25 to supply hydrogen to the anode and the air compressor 42 to supply air to the cathode. Furthermore, when the power required by the load decreases, the controller 81 stops the supply of hydrogen and / or air to the FC stack 11, thereby setting the FC stack 11 to an idle state.

[0033] When the controller 81 detects that the industrial vehicle's main switch has been turned key-off during the power generation sequence, it starts the stop sequence. In the stop sequence, first the controller 81 charges an auxiliary power source (not shown), such as a capacitor. After this, the controller 81 executes the stop process. That is, the controller 81 controls the main valve 23, the regulator 24, and the injector 25 to stop the supply of hydrogen from the hydrogen tank 22 to the FC stack 11. The controller 81 also controls the air compressor 42 and the air shutoff valve 43 to stop the supply of air to the FC stack 11. As a result, the FC stack 11 transitions to a standby state.

[0034] Fig. 3 is a diagram for explaining the concentration of hydrogen inside the FC stack 11. In Fig. 3, the vertical size (that is, the height) represents the concentration of each gas.

[0035] In the above-mentioned shutdown process, the controller 81 stops the supply of air to the cathode and temporarily increases the pressure of the hydrogen supplied to the anode. This increases the hydrogen concentration in the anode compartment, as shown in Fig. 3A. In other words, the FC stack 11 becomes hydrogen-rich.

[0036] In the standby state, the high concentration of hydrogen in the anode compartment permeates to the cathode side. The oxygen remaining in the cathode compartment reacts with the hydrogen permeating from the anode to become water. Therefore, after a certain time has elapsed after the completion of the shutdown process, there is substantially no oxygen left in the FC stack 11, as shown in FIG. 3B. This suppresses the deterioration of the catalyst.

[0037] Note that after a long enough time has passed since the shutdown process was completed, cross leakage between the anode and cathode will result in the anode and cathode compartments being substantially identical to each other. In the example shown in Figure 3B, hydrogen, water, and nitrogen are present in each compartment.

[0038] In the start-up sequence, after a system check, a hydrogen supplying step is first performed. That is, hydrogen is supplied to the anode. This increases the hydrogen concentration in the anode compartment as shown in FIG. 3C. Next, an air supplying step is performed. That is, air is supplied to the cathode. At this time, the hydrogen remaining in the cathode compartment is exhausted to the outside by the air supplied to the cathode. As a result, substantially no hydrogen remains in the cathode compartment as shown in FIG. 3D. After this, the operation mode of the fuel cell system 1 transitions from the start-up sequence to the power generation sequence.

[0039] In this way, when the fuel cell system 1 operates according to a predetermined sequence, in the standby state after a predetermined time has elapsed since the completion of the shutdown process, all of the oxygen in the FC stack 11 is consumed. At this time, the hydrogen concentration in the FC stack 11 is maintained at a relatively low level.

[0040] In contrast, if the fuel cell system 1 is operated outside of the predetermined sequence, a high hydrogen concentration state may be maintained within the FC stack 11. For example, Figure 4 shows a case in which, after the hydrogen supplying process has been performed in the startup sequence, the main switch of the industrial vehicle is turned off before the air supplying process is performed. Note that the states shown in Figures 4A to 4C are the same as the states shown in Figures 3A to 3C, respectively.

[0041] When the hydrogen supply step is performed in the start-up sequence, the hydrogen concentration in the anode compartment increases, as shown in FIG. 4C. If the start-up sequence then ends without the air supply step being performed and the system transitions to a standby state, the hydrogen in the FC stack 11 remains in the FC stack 11 without being exhausted to the outside. Then, due to cross leakage between the anode and cathode, some of the hydrogen in the anode compartment permeates into the cathode compartment. As a result, the hydrogen concentration in the cathode compartment increases, as shown in FIG. 4D.

[0042] Here, the anode off-gas (gas exhausted from the anode compartment) is diluted by the diluter 63 shown in FIG. 1 so that the hydrogen concentration is equal to or lower than a predetermined threshold level. However, in many cases, fuel cell systems do not have a function for diluting the cathode off-gas (gas exhausted from the cathode compartment). Therefore, if the startup sequence is performed following the standby state shown in FIG. 4D, there is a risk that high-concentration hydrogen will be exhausted from the cathode compartment when air is supplied to the cathode in the air supply step. In this case, the hydrogen sensor 71 may detect high-concentration hydrogen gas, and the controller 81 or a higher-level system may output an alarm. Note that if the above-mentioned procedure (i.e., the procedure in which the key is turned off without performing the air supply step after the hydrogen supply step) is repeated, there is a risk that the hydrogen concentration in the cathode compartment may further increase.

[0043] In this embodiment, the fuel cell system 1 is mounted on an industrial vehicle such as a forklift. Generally, industrial vehicles are frequently started (key on) and stopped (key off). For this reason, an operator of the industrial vehicle may operate the fuel cell system 1 outside of a predetermined sequence. For example, there are cases where the main switch of the industrial vehicle is turned off in the middle of the startup sequence of the fuel cell system 1. Therefore, when the fuel cell system 1 is mounted on an industrial vehicle, it is preferable that the fuel cell system 1 has a function for preventing a situation in which high concentrations of hydrogen are exhausted from the cathode compartment.

[0044] Therefore, the fuel cell system 1 according to the embodiment of the present invention has a function to prevent a situation in which high concentration hydrogen is exhausted from the cathode compartment. This function is realized by the controller 81 executing the procedure of the flowchart shown in FIG.

[0045] 5 is a flowchart showing an example of the operation of the fuel cell system 1 according to an embodiment of the present invention. In this embodiment, when the key-on of the main switch of the industrial vehicle is detected in S1 (system startup), the controller 81 executes the processes from S2 onward.

[0046] In S2 to S3, the controller 81 waits for a stop command resulting from key-off while controlling the FC stack 11. That is, when the fuel cell system 1 is started up in S1, the controller 81 executes the startup sequence shown in FIG. 2 while monitoring for a stop command, and then executes a power generation sequence. When a stop command is detected, the process of the controller 81 proceeds to S4. In a normal sequence assumed by the fuel cell system 1, the controller 81 receives a stop command during the power generation sequence. However, for example, if an operator of the industrial vehicle turns off the main switch of the industrial vehicle in the middle of the startup sequence of the fuel cell system 1, the controller 81 will receive a stop command in the middle of the startup sequence.

[0047] In S4, the controller 81 determines whether the fuel cell system 1 is in the startup sequence when the stop command is received. If the fuel cell system 1 is not in the startup sequence, the controller 81 determines that the key-off has occurred during the power generation sequence. Here, the procedure for key-off during the power generation sequence is a normal operation that follows a predetermined sequence, so the controller 81 stops the fuel cell system 1 in S9. That is, the stop sequence shown in FIG. 2 is executed.

[0048] If a stop command is received during the start-up sequence, the controller 81 determines in S5 whether the hydrogen supplying process had already started when the stop command was received. If the hydrogen supplying process has not yet started, the hydrogen concentration in the anode compartment should not have increased. In this case, even if the fuel cell system 1 is stopped and transitioned to a standby state and cross leakage occurs between the anode and the cathode, the hydrogen concentration in the cathode compartment will not increase. In other words, even if the gas in the cathode compartment is exhausted by the air supplying process in the next start-up sequence, high concentration hydrogen will not be discharged. Therefore, in this case as well, the controller 81 stops the fuel cell system 1 in S9.

[0049] If the fuel cell system 1 is in the startup sequence and the hydrogen supplying process has already started when the shutdown command is received, the controller 81 determines in S6 whether the air supplying process has ended. If the air supplying process has ended, the hydrogen in the cathode compartment has been sufficiently discharged, as shown in Fig. 3D. Therefore, in this case as well, the controller 81 shuts down the fuel cell system 1 in S9.

[0050] If the fuel cell system 1 is in the start-up sequence when the stop command is received, the hydrogen supplying step has already started, and the air supplying step has not yet ended, the hydrogen concentration in the cathode compartment may become high after a certain time has elapsed, as described with reference to Figures 4C and 4D. In this case, when the gas in the cathode compartment is exhausted by the air supplying step in the next start-up sequence, high concentration hydrogen may be discharged.

[0051] Therefore, in this case, the controller 81 determines that there is a predetermined amount or more of hydrogen in the cathode compartment, and executes the air supplying step in S7. That is, the controller 81 controls the air compressor 42 and the air shutoff valve 43 to supply air to the cathode of the FC stack 11, thereby discharging the gas in the cathode compartment. At this time, the hydrogen remaining in the cathode compartment is diluted with the newly supplied air and then discharged. Note that "there is a predetermined amount or more of hydrogen in the cathode compartment" means, for example, a state in which hydrogen remains in the cathode compartment to such an extent that there is a risk that a high concentration of hydrogen (for example, a concentration exceeding a reference value) will be discharged from the fuel cell system 1.

[0052] For example, if the air injection process has not yet started, the controller 81 executes the air injection process as normal. If the air injection process is in progress, the controller 81 continues the air injection process until the end. In either case, it is preferable to supply air to the cathode so that the concentration of hydrogen in the cathode compartment is sufficiently reduced or the hydrogen in the cathode compartment is sufficiently exhausted. Then, after a predetermined time has elapsed, the controller 81 stops the fuel cell system 1 in S8.

[0053] Thus, according to the embodiment of the present invention, if the key is turned off before the air pumping process is completed in the startup sequence, the controller 81 forcibly performs the air pumping process. That is, even if the key is turned off before the air pumping process is performed or during the air pumping process, the air pumping process is performed to the end. As a result, the FC stack 11 transitions to the state shown in Fig. 3D. That is, the cathode compartment is in a state where there is about 20 percent oxygen and the hydrogen concentration is sufficiently low.

[0054] After this, cross leakage progresses between the anode and the cathode. That is, gas permeates through the electrolyte membrane between the anode and the cathode so that the partial pressures of the gas in the anode compartment and the cathode compartment are substantially the same. At this time, when the concentration of hydrogen in the anode compartment is high, hydrogen permeates from the anode to the cathode. On the other hand, oxygen is present in the cathode compartment due to the air supply process performed in S7. Therefore, the hydrogen that has permeated into the cathode compartment reacts with oxygen and turns into water, so that even after a predetermined time has passed, no hydrogen remains in the cathode compartment, or even if it does, the concentration is sufficiently low. Therefore, even if the gas in the cathode compartment is exhausted by the air supply process in the next startup sequence, the discharge of high concentration hydrogen is suppressed.

[0055] <Variations> According to an embodiment of the present invention, when hydrogen is present in the cathode compartment of the FC stack 11 with the cathode sealed by the air shutoff valve 43 and the air pressure regulating valve 62, the controller 81 exhausts the hydrogen in the cathode compartment by supplying air to the cathode using the air compressor 42. Here, the state in which the cathode is sealed includes the standby state of the fuel cell system 1. In other words, when hydrogen is expected to be present in the cathode compartment in the standby state, the controller 81 may execute the air supplying process. For example, if the fuel cell system 1 is equipped with a sensor that measures the hydrogen concentration in the cathode compartment, the controller 81 may execute the above-mentioned air supplying process when the hydrogen concentration in the cathode compartment exceeds a predetermined threshold value. [Explanation of symbols]

[0056] 1. Fuel cell system 11 FC Stack 21 Hydrogen supply channel 22 Hydrogen Tank 23 Main valve 24 Regulator 25 Injector 41 Air supply passage 42 Air Compressor 43 Air Shut Off Valve 61 Exhaust flow path 62 Air pressure adjusting valve 63 Diluter 81 Controller

Claims

1. A fuel cell; a cathode flow path connected to a cathode of the fuel cell; an air supply means provided on the cathode flow path for supplying air to the cathode; a sealing means provided on the cathode flow path for sealing the cathode; A controller for controlling a state of the fuel cell, When it is determined that a predetermined amount of hydrogen or more is present in the cathode compartment of the fuel cell with the cathode sealed by the sealing means, the controller uses the air supply means to supply air to the cathode, thereby discharging gas in the cathode compartment. A fuel cell system comprising:

2. the controller has a function of controlling a start-up sequence including a hydrogen supplying step of supplying hydrogen to an anode of the fuel cell, and an air supplying step of supplying air to a cathode of the fuel cell after the hydrogen supplying step; When a command to shut down the fuel cell is received during the start-up sequence and before the air supply step is completed, the controller performs the air supply step to exhaust gas in the cathode compartment.

2. The fuel cell system according to claim 1 .

3. the cathode flow path includes an air supply flow path that supplies air to the cathode and an exhaust flow path that exhausts cathode off-gas from the cathode compartment; The sealing means includes an air shutoff valve provided on the air supply passage and an air pressure regulating valve provided on the exhaust passage.

2. The fuel cell system according to claim 1 .

4. A fuel cell; A controller for controlling a state of the fuel cell; a hydrogen supply means for supplying hydrogen to the anode of the fuel cell under the control of the controller; an air compressor that supplies air to the cathode of the fuel cell under the control of the controller; the controller has a function of controlling a start-up sequence including a hydrogen supplying step of supplying hydrogen to an anode of the fuel cell, and an air supplying step of supplying air to a cathode of the fuel cell after the hydrogen supplying step; When a command to shut down the fuel cell is received during the start-up sequence and before the air supply step is completed, the controller performs the air supply step to exhaust gas in the cathode compartment. A fuel cell system comprising:

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