JP2019087357A - Fuel cell system - Google Patents

Abstract

To suppress the deterioration of fuel consumption due to excessive hydrogen discharged by crossover.SOLUTION: A fuel cell system includes: a fuel cell which has an anode supplied with hydrogen and a cathode supplied with air; a pressure sensor which detects the pressure of the anode; a compressor which sends air to the cathode; a valve which adjusts the pressure of the cathode; a secondary cell; and a control portion which closes the valve if difference between the pressure of the anode detected by the pressure sensor and the pressure of the cathode after stopping the compressor is a predetermined value or more when stopping the generation of the fuel cell, calculates excessive hydrogen transmitting from the anode to the cathode on the basis of the detected pressure of the anode, obtains a command current value for consuming the excessive hydrogen by generation, outputs power from the fuel cell on the basis of the command current value, and stores the outputted power in the secondary cell.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fuel cell system.

  Conventionally, as in the fuel cell system described in Patent Document 1, for example, when there is no demand for power generation to the fuel cell, the flow rates of air and hydrogen as reaction gases supplied to the fuel cell may be reduced.

JP, 2013-161571, A

  When the compressor is stopped to reduce the air flow rate, the cathode may be opened to the atmosphere, and the pressure of the cathode may be reduced to about atmospheric pressure. On the other hand, the pressure of the anode is desirably maintained because it is a circulating system connected to the hydrogen tank. For this reason, the pressure difference between the anode and the cathode increases, and the pressure difference may cause the hydrogen of the anode to permeate the electrolyte membrane, move to the cathode, and be discharged to the atmosphere. Such excess hydrogen discharged due to so-called crossover does not contribute to the power generation of the fuel cell, and there is a possibility that the fuel efficiency will be deteriorated. Therefore, there is a need for a technology that can suppress the deterioration of fuel efficiency due to the excess hydrogen emitted by the crossover.

  The present invention has been made to solve at least a part of the above-mentioned problems, and can be realized as the following modes.

  According to one aspect of the present invention, a fuel cell system is provided. The fuel cell system comprises: a fuel cell having an anode supplied with hydrogen gas and a cathode supplied with air; a pressure sensor for detecting the pressure of the anode; a compressor for transmitting the air to the cathode; A valve for adjusting the pressure of the cathode; a secondary battery; a control unit; and after stopping the pressure of the anode detected by the pressure sensor and the compressor when stopping the power generation of the fuel cell When the difference between the pressure of the cathode and the pressure is equal to or greater than a predetermined value; closing the valve; and based on the pressure of the anode detected, the amount of excess hydrogen transmitted from the anode to the cathode Calculating; determining a command current value for consuming the surplus hydrogen by power generation; causing the fuel cell to output power based on the command current value; It comprises; a control unit for storing electric power to the secondary battery. According to the fuel cell system of this aspect, since the fuel cell outputs electric power based on the command current value that causes the surplus hydrogen to be consumed by power generation, and the output electric power is stored in the secondary battery, the surplus hydrogen is used for power generation. It is possible to suppress the deterioration of the fuel efficiency due to the excess hydrogen emitted by the crossover.

  The present invention can also be realized in various forms other than the fuel cell system. For example, the present invention can be realized in the form of a control method of a fuel cell system, a vehicle including a fuel cell system, and the like.

It is an explanatory view showing a schematic structure of a fuel cell system. It is a flowchart which shows the procedure of surplus hydrogen consumption control. It is a time chart which shows an example of control.

A. Embodiment:
A-1. Fuel cell system configuration:
FIG. 1 is an explanatory view showing a schematic configuration of a fuel cell system according to an embodiment of the present invention. Fuel cell system 10 is mounted on a fuel cell vehicle (not shown) and supplies power to a load 100 including a drive motor of the vehicle.

  The fuel cell system 10 includes a fuel cell 20, a cathode gas supply / discharge system 30, an anode gas supply / discharge system 50, a DC / DC converter 70, a secondary battery 80, and a control unit 90. The fuel cell system 10 may further include a refrigerant circulation system (not shown) for cooling the fuel cell 20 in order to keep the temperature of the fuel cell 20 in a predetermined range.

  The fuel cell 20 is constituted by a so-called polymer electrolyte fuel cell, and generates electric power upon supply of an anode gas and a cathode gas. The fuel cell 20 has a stack structure in which a plurality of single cells 21 are stacked. Each single cell 21 has a membrane electrode assembly (not shown) in which electrodes are disposed on both sides of an electrolyte membrane (not shown), and a pair of separators (not shown) sandwiching the membrane electrode assembly. In each unit cell 21 constituting the fuel cell 20, an anode 22 to which an anode gas is supplied and a cathode 23 to which a cathode gas is supplied are formed via an electrolyte membrane. In FIG. 1, the anode 22 and the cathode 23 are shown as a schematic view.

  The cathode gas supply / discharge system 30 supplies air as a cathode gas to the fuel cell 20 and discharges it. The cathode gas supply / discharge system 30 includes a cathode gas supply passage 31, an air flow meter 32, a compressor 33, a cathode pressure sensor 34, an inlet valve 35, a bypass passage 41, a bypass valve 42, and a cathode gas discharge passage. 45 and a cathode pressure regulating valve 46.

  The cathode gas supply passage 31 constitutes a flow passage of air supplied to the fuel cell 20. The air flow meter 32 detects the flow rate of air taken into the cathode gas supply passage 31. The compressor 33 compresses air and pumps it to the fuel cell 20. The cathode pressure sensor 34 is disposed closer to the fuel cell 20 than the compressor 33 in the cathode gas supply passage 31, and detects the pressure of air supplied to the fuel cell 20. The inlet valve 35 is disposed between the compressor 33 and the fuel cell 20 and closer to the fuel cell 20 than the connection portion with the bypass flow passage 41, and opens and closes in accordance with the flow of supplied air. The inlet valve 35 is normally closed and opens when air having a predetermined pressure is supplied from the compressor 33.

  The bypass passage 41 connects the cathode gas supply passage 31 and the cathode gas discharge passage 45 with each other. The bypass valve 42 is disposed in the bypass flow passage 41, and adjusts the flow rate of air flowing through the bypass flow passage 41 in accordance with an instruction from the control unit 90. The cathode gas discharge passage 45 discharges the cathode exhaust gas discharged from the fuel cell 20 to the outside of the fuel cell system 10. The cathode pressure regulating valve 46 is disposed in the cathode gas discharge passage 45, and adjusts the pressure of the cathode 23 in accordance with an instruction from the control unit 90.

  The anode gas supply and discharge system 50 supplies hydrogen as an anode gas to the fuel cell 20 and discharges it. The anode gas supply / discharge system 50 includes a hydrogen tank 51, an anode gas supply passage 52, a tank pressure sensor 53, a main stop valve 54, an anode pressure regulating valve 55, an injector 56, an anode pressure sensor 57, and an anode gas. A discharge path 61, a gas-liquid separator 62, a circulation pipe 63, a hydrogen pump 64, and an exhaust drainage valve 65 are provided.

  The hydrogen tank 51 stores high pressure hydrogen. The anode gas supply passage 52 constitutes a flow passage of hydrogen supplied from the hydrogen tank 51 to the fuel cell 20. The tank pressure sensor 53 detects the pressure of the hydrogen tank 51. The main stop valve 54, the anode pressure regulating valve 55, the injector 56, and the anode pressure sensor 57 are arranged in this order from the side close to the hydrogen tank 51 in the anode gas supply passage 52, and are driven by the control unit 90. The main stop valve 54 turns on and off the supply of hydrogen from the hydrogen tank 51. The anode pressure regulating valve 55 regulates the pressure of hydrogen supplied to the fuel cell 20. The injector 56 is configured by an electromagnetic drive type on-off valve, and is driven according to the drive cycle and the valve opening time set by the control unit 90 to inject hydrogen. The anode pressure sensor 57 is disposed closer to the fuel cell 20 in the anode gas supply passage 52 than the connection portion with the circulation pipe 63, and detects the pressure of the anode 22.

  The anode gas discharge passage 61 connects the fuel cell 20 and the gas-liquid separator 62. The gas-liquid separator 62 separates liquid water from the liquid-water mixed anode exhaust gas discharged from the fuel cell 20. The circulation pipe 63 connects the gas-liquid separator 62 and the fuel cell 20 side of the injector 56 of the anode gas supply passage 52. The hydrogen pump 64 is disposed in the circulation pipe 63 and circulates the anode exhaust gas containing hydrogen gas not used for the electrochemical reaction to the anode gas supply passage 52. The exhaust / drain valve 65 is normally closed and opens in response to an instruction from the control unit 90. Thus, the liquid water and the impurity gas separated by the gas-liquid separator 62 are discharged to the outside of the fuel cell system 10.

  The DC / DC converter 70 is disposed between the fuel cell 20 and the secondary battery 80 and the load 100. The DC / DC converter 70 converts the output voltage of the fuel cell 20 into a desired voltage.

  The secondary battery 80 is a chargeable / dischargeable battery, and is configured of a lithium ion battery. The lithium ion battery may be replaced by any other secondary battery such as a nickel hydrogen battery. The secondary battery 80 functions as a power source of the fuel cell system 10 together with the fuel cell 20, and stores the power generated by the fuel cell 20.

  The load 100 may include, in addition to the drive motor of the fuel cell vehicle, auxiliary devices such as the compressor 33 and the hydrogen pump 64 and vehicle auxiliary devices such as an air conditioner (air conditioner) provided in the fuel cell vehicle. The load 100 is supplied with power from the fuel cell 20 or the secondary cell 80 or both the fuel cell 20 and the secondary cell 80 simultaneously via an inverter (not shown).

  The control unit 90 is a microcomputer provided with a central processing unit (CPU: Central Processing Unit) and a main storage device, and is configured as an electronic control unit. In addition to various sensors such as the cathode pressure sensor 34, the tank pressure sensor 53, and the anode pressure sensor 57, the control unit 90 receives detection signals from a sensor group such as an accelerator opening sensor and a vehicle speed sensor (not shown) of the fuel cell vehicle. Be done. Further, the control unit 90 includes various valves such as the inlet valve 35, the bypass valve 42, the cathode pressure regulating valve 46, the main stop valve 54, the anode pressure regulating valve 55, the injector 56, and the exhaust drainage valve 65, the compressor 33 and the hydrogen pump 64. The drive signal is output to each unit related to the power generation of the fuel cell 20, such as an auxiliary machine including the above. The control unit 90 controls the power generation of the fuel cell system 10 by executing a control program stored in the main storage device.

  The control unit 90 switches the operation mode of the fuel cell system 10 to the normal operation mode, the non-power generation operation mode, and the like. The normal operation mode is a mode in which the fuel cell system 10 receives a power generation request, generates the fuel cell 20 according to the required power, and outputs the power. In the power generation request, the external power generation request accompanying the operation of the vehicle on which the fuel cell system 10 is mounted (for example, depression of the accelerator pedal, the turning on of the air conditioning facility, etc.) and the driving of the accessories of the fuel cell system 10 Internal power generation requirements are included. The non-power generation operation mode is a mode in which the required power to the fuel cell system 10 is equal to or less than a predetermined value and there is no output request for power to the fuel cell 20.

  The control unit 90 switches the operation mode of the fuel cell system 10 from the normal operation mode to the non-power generation operation mode, for example, when the vehicle on which the fuel cell system 10 is mounted stops or runs at low speed. , Stop the power generation of the fuel cell 20. In the non-power generation mode, the amount of air and hydrogen supplied to the fuel cell 20 is reduced. More specifically, the compressor 33 is stopped to stop pumping air to the fuel cell 20, and the anode pressure regulating valve 55 is closed, and the injector 56 and the hydrogen pump 64 are stopped to supply hydrogen to the fuel cell 20. stop.

  In the non-power generation operation mode, the target pressure of the anode 22 is set to a pressure lower than the pressure of the anode 22 in the normal operation mode and higher than the atmospheric pressure. The controller 90 controls the pressure of the anode 22 to a target pressure. Specifically, for example, the pressure of the anode 22 is controlled to be 120 kPa. In order to maintain the target pressure, the injector 56 and the hydrogen pump 64 may be appropriately driven in the non-power generation operation mode.

  In the non-power generation operation mode, the cathode pressure regulating valve 46 is opened as normal control. In the non-power generation operation mode, since the compressor 33 is stopped as described above, the cathode 23 is opened to the atmosphere when the cathode pressure regulating valve 46 is opened. As a result, the pressure of the cathode 23 drops to about 101.3 kPa, which is the atmospheric pressure. On the other hand, it is desirable that the pressure of the anode 22 be maintained since the anode 22 is a circulating system connected to the hydrogen tank 51. Therefore, due to the pressure difference between the cathode 23 and the anode 22, hydrogen of the anode 22 may permeate through the electrolyte membrane, move to the cathode 23, and be discharged to the atmosphere. Such hydrogen that is discharged by so-called crossover (hereinafter, also referred to as “surplus hydrogen”) does not contribute to the power generation of the fuel cell 20, and there is a possibility that the fuel efficiency may be deteriorated. Therefore, in the fuel cell system 10 of the present embodiment, when the operation mode of the fuel cell system 10 is shifted from the normal operation mode to the non-power generation operation mode to stop the power generation of the fuel cell 20, excess hydrogen consumption will be described below. The control is executed, and the power output from the fuel cell 20 is stored in the secondary battery 80 by the power generation using the excess hydrogen, thereby suppressing the deterioration of the fuel efficiency.

  In the present embodiment, “excess hydrogen” means hydrogen discharged by crossover, and more specifically, when the power generation of the fuel cell 20 is stopped, the pressure of the anode 22 detected by the anode pressure sensor 57 It means an amount of hydrogen corresponding to the pressure difference between the pressure and the target pressure of the anode 22 in the non-power generation operation mode. Further, in the present embodiment, the cathode pressure regulating valve 46 corresponds to a sub-concept of a valve in the means for solving the problem, and the anode pressure sensor 57 corresponds to a sub-concept of a pressure sensor in the means for solving the problem. Do.

A-2. Excess hydrogen consumption control:
FIG. 2 is a flowchart showing the procedure of surplus hydrogen consumption control. The excess hydrogen consumption control is repeatedly executed after the fuel cell system 10 is started by pressing a starter switch (not shown) of the fuel cell vehicle.

  The control unit 90 detects whether there is a demand for output to the fuel cell 20 (step S210). For example, when the accelerator opening detected by the accelerator opening sensor is zero, the vehicle speed detected by the vehicle speed sensor is zero, and there is no storage request to the secondary battery 80, it is detected that there is no output request. Otherwise, it detects that there is an output request. If it is detected that there is an output request to the fuel cell 20 (step S210: YES), the control unit 90 sets the operation mode of the fuel cell system 10 to the normal operation mode (step S290), and returns to step S210.

  On the other hand, when it is detected that there is no output request to the fuel cell 20 (step S210: NO), the control unit 90 sets the operation mode of the fuel cell system 10 to the non-power generation operation mode and stops the compressor 33 ( Step S215). When the compressor 33 is stopped, the supply of air to the cathode 23 almost disappears, and the amount of supply is 0 to 3 NL / min. Here, 1 NL / min means that 1 L / min of air in a reference state (pressure 101.3 kPa, temperature 0 ° C., humidity 0%) flows.

  The control unit 90 determines whether the difference between the pressure of the anode 22 and the pressure of the cathode 23 is equal to or greater than a predetermined value X (step S220). In this embodiment, the determination is performed using the pressure of the anode 22 detected by the anode pressure sensor 57 and the pressure of the cathode 23 in the non-power generation operation mode, that is, 101.3 kPa which is the atmospheric pressure. The predetermined value X is predetermined based on the pressure of the cathode 23 and the target pressure (120 kPa) of the anode 22 in the non-power generation operation mode, and is set to about 20 kPa in the present embodiment. The predetermined value X is stored in advance in the main storage device of the control unit 90.

  When it is determined that the difference between the pressure of the anode 22 and the pressure of the cathode 23 is equal to or greater than the predetermined value X (step S220: YES), the control unit 90 closes the cathode pressure regulating valve 46 (step S225).

  When the cathode pressure regulating valve 46 is closed, the air of the cathode 23 is secured without the cathode 23 being open to the atmosphere, so that such air can be used for consumption of excess hydrogen. When closing the cathode pressure regulating valve 46, the control unit 90 may close the cathode pressure regulating valve 46 while monitoring that the pressure of the cathode 23 detected by the cathode pressure sensor 34 does not exceed a predetermined upper limit. . The upper limit value is set, for example, to the withstand voltage of the cathode 23, and is stored in advance in the main storage device of the control unit 90. If the pressure of the cathode 23 exceeds the upper limit value, the control unit 90 may proceed to step S280 and open the cathode pressure regulating valve 46.

  The controller 90 calculates the amount of surplus hydrogen based on the pressure of the anode 22 (step S230). For example, when the pressure of the anode 22 is 200 kPa and the target pressure of the anode 22 in the non-power generation operation mode is 120 kPa, the excess hydrogen amount is multiplied by the volume of the anode 22 as a hydrogen amount of 80 kPa of the pressure difference. Calculated by The excess hydrogen amount may be calculated by further multiplying the correction coefficient according to the temperature of the anode 22.

  The control unit 90 obtains a command current value for causing the fuel cell 20 to consume the surplus hydrogen amount calculated in step S230 (step S235). The controller 90 causes the fuel cell 20 to output electric power based on the command current value obtained in step S235 (step S240). The voltage of the fuel cell 20 is also controlled based on the determined command current value and the IV characteristic MAP stored in advance in the main storage device of the control unit 90. The controller 90 stores the power output in step S240 in the secondary battery 80 (step S245), and returns to step S220.

  In step S240, the control unit 90 causes the fuel cell 20 to output power while monitoring that the pressure of the anode 22 detected by the anode pressure sensor 57 does not fall below the target pressure in the non-power generation operation mode. Good. If the pressure of the anode 22 falls below the target pressure, the process may proceed to step S280 to open the cathode pressure regulating valve 46, and control may be performed to maintain the target pressure by driving the injector 56 and the hydrogen pump 64. It is also good.

  When the excess hydrogen is consumed by power generation and the pressure of the anode 22 decreases to a target pressure in the non-power generation operation mode, the difference between the pressure of the anode 22 and the pressure of the cathode 23 does not exceed the predetermined value X. When it is determined that the difference between the pressure of the anode 22 and the pressure of the cathode 23 is not greater than or equal to the predetermined value X (step S220: NO), the control unit 90 opens the cathode pressure regulating valve 46 (step S280). Return.

  FIG. 3 is a time chart showing an example of control. The vertical axis indicates the presence or absence of power generation request, anode pressure control, current control, air flow control, cathode pressure control, and cathode pressure regulating valve control, and the horizontal axis indicates time. From time t0 to t3 and after time t6, there is a power generation request to the fuel cell 20, and control of the normal operation mode is performed. Between time t3 and time t6, there is no power generation request to the fuel cell 20, and control of the non-power generation operation mode is performed.

  During control in the normal operation mode, the control unit 90 controls the pressure of the anode 22, the current, the air flow rate of the cathode 23, the pressure of the cathode 23, and the cathode pressure regulating valve 46 according to the output demand. For example, between time t1 and time t2 and after time t7, as compared between time t0 and time t1, between time t2 and time t3, and between time t6 and time t7. Since the output demand is reduced, control is performed to reduce the pressure of the anode 22 from 200 kPa to 190 kPa, and the command current value and the like are reduced.

  When the power generation request to the fuel cell 20 disappears at time t3, the pressure of the anode 22 is set and controlled to 120 kPa which is the target pressure in the non-power generation operation mode. In FIG. 3, the actual pressure of the anode 22 detected by the anode pressure sensor 57 is indicated by a broken line, and the surplus hydrogen is indicated by hatching. In the present embodiment, the amount of the excess hydrogen is calculated in step S230 of FIG.

  The control unit 90 performs current control based on the command current value calculated in step S235 of FIG. In the example of FIG. 3, the time from time t3 to time t4 is controlled by the first command current value, and the time from time t4 to time t5 is controlled by the second command current value. As described above, the actual pressure of the anode 22 detected by the anode pressure sensor 57 may be monitored at a predetermined timing, and current control may be performed while calculating the command current value each time according to the actual hydrogen pressure.

  The controller 90 controls the flow rate of the air supplied to the cathode 23 to 0 to 3 NL / min by stopping the compressor 33 at time t3. In FIG. 3, the actual air flow rate detected by the air flow meter 32 is indicated by a broken line. The actual air flow rate gradually decreases as the compressor 33 stops. Although not shown, the actual pressure of the cathode 23 detected by the cathode pressure sensor 34 also gradually decreases as power is generated between time t3 and time t5.

  In the non-power generation operation mode, as the normal control, the compressor 33 is stopped and the cathode pressure regulating valve 46 is opened, so that the cathode 23 is opened to the atmosphere, and the pressure of the cathode 23 is controlled to be equal to the atmospheric pressure. However, in the present embodiment, when transitioning from the normal operation mode to the non-power generation operation mode, the cathode pressure regulating valve 46 is transiently closed to control surplus hydrogen consumption from time t3 to time t5. The air of the cathode 23 is secured without opening the cathode 23 to the atmosphere. The control unit 90 causes the surplus hydrogen and the air of the secured cathode 23 to perform power generation in step S240 of FIG. 2. When the surplus hydrogen is consumed by power generation at time t5 and the pressure of the anode 22 becomes the target pressure of the non-power generation operation mode (step S230: NO), the control unit 90 opens the cathode pressure regulating valve 46 (step S280).

  According to the fuel cell system 10 of the present embodiment described above, the amount of excess hydrogen is calculated based on the pressure of the anode 22, the command current value for consuming the excess hydrogen by power generation is determined, and the cathode pressure regulating valve 46 is closed. Since electric power is output from the fuel cell 20 based on the command current value and the output electric power is stored in the secondary battery 80, surplus hydrogen can be used for power generation, and deterioration of fuel efficiency due to surplus hydrogen discharged by crossover is It can be suppressed.

  Further, since the cathode pressure regulating valve 46 is transiently closed, air of the cathode 23 for use in power generation of surplus hydrogen can be secured. For this reason, it can suppress that the quantity of the air of the cathode 23 runs short with respect to the quantity of the surplus hydrogen of the anode 22, and the surplus hydrogen can be consumed by electric power generation also in the state which stopped the compressor 33.

  In addition, since excess hydrogen is consumed by power generation when it is determined that the difference between the pressure of the anode 22 and the pressure of the cathode 23 is a predetermined value X or more, the pressure of the anode 22 is lower than the target pressure due to excessive power generation. The pressure of the anode 22 in the non-power generation operation mode can be maintained at an appropriate value.

C. Other embodiments:
C-1. Other embodiment 1:
In the excess hydrogen consumption control in the above embodiment, the determination is performed using the pressure of the cathode 23 in the non-power generation operation mode, that is, 101.3 kPa which is the atmospheric pressure in step S220, but the present invention is limited thereto It is not a thing. For example, the target pressure of the cathode 23 in the non-power generation operation mode may be determined, and the determination may be performed using the target pressure of the cathode 23 instead of the atmospheric pressure. This configuration also achieves the same effect as that of the above embodiment.

C-2. Other embodiment 2:
In the above embodiment, the fuel cell system 10 is mounted on a fuel cell vehicle and used, but may be mounted on any other movable body such as a ship or a robot instead of the vehicle, and a stationary fuel cell It may be used as

  The present invention is not limited to the above-described embodiment, and can be realized in various configurations without departing from the scope of the invention. For example, the technical features in the embodiments corresponding to the technical features in each of the modes described in the section of the summary of the invention can be used to solve some or all of the problems described above, or one of the effects described above. Replacements and combinations can be made as appropriate to achieve part or all. Also, if the technical features are not described as essential in the present specification, they can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell system 20 ... Fuel cell 21 ... Single cell 22 ... Anode 23 ... Cathode gas supply and discharge system 31 ... Cathode gas supply path 32 ... Air flow meter 33 ... Compressor 34 ... Cathode pressure sensor 35 ... Inlet valve 41 ... Bypass flow path 42 ... bypass valve 45 ... cathode gas discharge path 46 ... cathode pressure control valve 50 ... anode gas supply / discharge system 51 ... hydrogen tank 52 ... anode gas supply path 53 ... tank pressure sensor 54 ... main stop valve 55 ... anode pressure control valve 56 ... injector 57 ... anode pressure sensor 61 ... anode gas discharge path 62 ... gas-liquid separator 63 ... circulation piping 64 ... hydrogen pump 65 ... exhaust drainage valve 70 ... DC / DC converter 80 ... secondary battery 90 ... control unit 100 ... Load X ... predetermined value

Claims (1)

A fuel cell system,
A fuel cell having an anode supplied with hydrogen gas and a cathode supplied with air;
A pressure sensor for detecting the pressure of the anode;
A compressor for delivering the air to the cathode;
A valve for adjusting the pressure of the cathode;
With a secondary battery,
The control unit,
When stopping the power generation of the fuel cell, the difference between the pressure of the anode detected by the pressure sensor and the pressure of the cathode after stopping the compressor is equal to or greater than a predetermined value.
Close the valve,
Based on the pressure of the anode detected, the amount of excess hydrogen transmitted from the anode to the cathode is calculated;
Determine a command current value that causes the surplus hydrogen to be consumed by power generation,
Causing the fuel cell to output power based on the command current value;
A control unit for storing the output electric power in the secondary battery;
A fuel cell system comprising:

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