Fuel cell system

Abstract

In a fuel cell system with multiple fuel cells, power generation can be started early during startup. [Solution] The fuel cell system 100 comprises a plurality of fuel cells, a fuel gas storage unit 2 in which fuel gas is stored, an on-off valve 25 positioned between each of the plurality of fuel cells' fuel gas supply passages PA1 and the fuel gas storage unit 2 to allow or block the flow of fuel gas through the fuel gas supply passage PA1, and a control unit that opens the on-off valve in response to an open command output from each of the plurality of fuel cells. When all of the plurality of fuel cells are functioning normally, the control unit opens the on-off valve 25 when an open command is output from at least one of the plurality of fuel cells.

Description

Technical Field

[0001] The present invention relates to a fuel cell system having a plurality of fuel cells.

Background Art

[0002] In recent years, in order to enable more people to access affordable, reliable, sustainable, and advanced energy, technological development related to fuel cells that contribute to energy efficiency has been carried out. As a technology related to this type of fuel cell, a technology related to the startup of a fuel cell system having a plurality of fuel cells is known (see, for example, Patent Document 1).

[0003] The fuel cell system described in Patent Document 1 includes a plurality of control units that individually control a plurality of fuel cells, and an integrated control unit that executes opening of a shut-off valve of a high-pressure tank in which fuel gas is stored. When it is determined that there is no abnormality in the plurality of fuel cells, the integrated control unit executes opening of the shut-off valve after receiving opening instructions from all of the plurality of control units. When it is determined that there is an abnormality in at least one of the plurality of fuel cells, the integrated control unit executes opening of the shut-off valve after receiving an opening instruction from at least one of the plurality of control units.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the system described in Patent Document 1 above, when it is determined that there is no abnormality in the plurality of fuel cells, the opening of the shut-off valve is executed after receiving opening instructions from all of the plurality of control units, so it tends to take time until the fuel cells start generating power.

Means for Solving the Problems

[0006] A fuel cell system according to one aspect of the present invention comprises a plurality of fuel cells, a fuel gas storage unit in which fuel gas is stored, a valve device disposed between each of the plurality of fuel cells and the fuel gas storage unit, which allows or blocks the flow of fuel gas through the fuel gas supply line, and a control unit which opens the valve device in response to an open command output from each of the plurality of fuel cells. When all of the plurality of fuel cells are functioning normally, the control unit opens the valve device when an open command is output from at least one of the plurality of fuel cells. [Effects of the Invention]

[0007] According to the present invention, it is possible to start generating electricity from a fuel cell at an earlier stage. [Brief explanation of the drawing]

[0008] [Figure 1] A schematic diagram showing the main components of a fuel cell system according to an embodiment of the present invention. [Figure 2] A block diagram schematically showing the control configuration of a fuel cell system according to an embodiment of the present invention. [Figure 3] A flowchart showing an example of the process executed by the individual controllers in Figure 2. [Figure 4] A flowchart showing an example of the process executed by the central controller in Figure 2. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to Figures 1 to 4. The fuel cell system according to the embodiment of the present invention has a plurality of fuel cells. This fuel cell system can be installed in a large fuel cell vehicle, such as a fuel cell bus. Hereinafter, each of the plurality of fuel cells may be referred to as a unit system. By having a fuel cell system equipped with a plurality of unit systems, the overall power generation can be increased, and sufficient power can be supplied to the drive motor of a large fuel cell vehicle.

[0010] The fuel cell system according to an embodiment of the present invention is characterized by a configuration that controls the flow of fuel gas when supplying fuel gas from a fuel gas tank in which fuel gas is stored to a plurality of unit systems. Figure 1 is a schematic diagram showing the main components of the fuel cell system 100 according to an embodiment of the present invention. Figure 1 mainly shows the fuel gas supply path.

[0011] As shown in Figure 1, the fuel cell system 100 has multiple unit systems 101. For convenience, Figure 1 shows an example where the fuel cell system 100 has a pair of unit systems 101A and 101B, but the fuel cell system 100 may have three or more unit systems 101. The configurations of the multiple unit systems 101A and 101B are identical to each other.

[0012] The unit system 101 includes a fuel cell stack 1, a fuel gas storage unit 2 in which fuel gas is stored, and a fuel gas supply unit 3 that supplies fuel gas from the fuel gas storage unit 2 to the fuel cell stack 1. The fuel gas is, for example, hydrogen.

[0013] The fuel gas supply unit 3 has a fuel gas flow path forming unit that forms a fuel gas supply flow path PA1 for supplying fuel gas from the fuel gas storage unit 2 to the fuel cell stack 1. Although not shown in the figures, the unit system 101 further includes an oxidant gas flow path forming unit that forms an oxidant gas supply flow path for supplying oxidant gas to the fuel cell stack 1, and a cooling medium flow path forming unit that forms a cooling medium supply flow path for supplying a cooling medium to the fuel cell stack 1. The oxidant gas is, for example, oxygen, and the cooling medium is, for example, water.

[0014] The fuel cell stack 1 is constructed by stacking multiple power generation cells. Each power generation cell has an electrolyte membrane, an anode separator positioned opposite one side of the electrolyte membrane, and a cathode separator positioned opposite the other side of the electrolyte membrane. The electrolyte membrane is, for example, a solid polymer electrolyte membrane. An anode electrode is formed on one side of the electrolyte membrane, and fuel gas is supplied to the anode electrode via the anode separator. A cathode electrode is formed on the other side of the electrolyte membrane, and oxidant gas is supplied to the cathode electrode via the cathode separator. The anode separator and cathode separator positioned between a pair of adjacent power generation cells are integrally constructed, and a cooling medium flows between these anode separator and cathode separator.

[0015] At the anode electrode, fuel gas (hydrogen) supplied via the anode separator is ionized by the action of a catalyst and moves to the cathode electrode side through the electrolyte membrane. The electrons generated at this time pass through an external circuit and are extracted as electrical energy. At the cathode electrode, oxidizing gas (oxygen) supplied via the cathode separator reacts with hydrogen ions introduced from the anode electrode and electrons that have moved from the anode electrode to produce water. The generated water provides appropriate humidity to the electrolyte membrane, and excess water is discharged to the outside.

[0016] The fuel gas storage unit 2 has multiple (for example, pairs) fuel gas tanks 20 connected in parallel. The number of fuel gas tanks 20 may be one or three or more. The gas inlets of the multiple fuel gas tanks 20 are each connected to a filling manifold 21. The filling manifolds 21 of the multiple unit systems 101A and 101B are connected to a filling port 23 via a flow path L1. The gas outlets of the multiple fuel gas tanks 20 are connected to a supply manifold 22 via an electromagnetic on-off valve (solenoid valve) 25. The supply manifolds 22 of the multiple unit systems 101A and 101B are connected to the fuel gas supply unit 3 via a flow path L2. In addition, the supply manifolds 22 of the multiple unit systems 101A and 101B are connected to each other via a connecting flow path L3.

[0017] With the on - off valve 25 shut off (closed), fuel gas is supplied to the fuel gas storage section 2 from the outside (for example, a hydrogen station) via the filling port 23. The supplied fuel gas is evenly guided to a plurality of fuel gas tanks 20 via the flow path L1 and the filling manifold 21, and high - pressure fuel gas is stored in the plurality of fuel gas tanks 20.

[0018] The fuel cell stack 1 has an inlet port 1a and an outlet port 1b. The fuel gas supply flow path PA1 is a flow path from the fuel gas tank 20 to the inlet port 1a, and includes a supply flow path PA11 provided between the connection flow path L3 and the inlet port 1a, a discharge flow path PA12 connected to the outlet port 1b, and a circulation flow path PA13 provided from the discharge flow path PA12 to the supply flow path PA11. An electromagnetic injector 31 for injecting fuel gas is arranged in the supply flow path FL11. The injector 31 can be configured as a plurality of injectors connected in parallel to each other. Further, an ejector 32 is arranged in the supply flow path FL11 between the injector 31 and the inlet port 1a.

[0019] At the end of the discharge flow path FL12, a gas - liquid separator 33 for separating moisture from the fuel gas (fuel exhaust gas) discharged from the outlet port 1b is connected. The water separated by the gas - liquid separator 33 is discharged to the outside via the flow path L4 and the drain valve 34. The gas - liquid separator 33 and the ejector 32 are connected via a circulation flow path PA23.

[0020] The ejector 32 has a nozzle portion, a suction portion, a confluence portion, and a diffuser portion. The fuel gas injected from the injector 31 passes through the small - diameter nozzle portion and then flows into the diffuser portion via the confluence portion. At this time, the fuel gas gas - liquid - separated by the gas - liquid separator 33 is sucked into the ejector 32 via the circulation flow path PA13 and the suction portion. The sucked fuel gas merges with the fuel gas that has passed through the nozzle portion at the confluence portion, and after being made into a uniform flow in the diffuser portion, it is supplied to the fuel cell stack 1 via the inlet port 1a.

[0021] FIG. 2 is a block diagram schematically showing the control configuration of the fuel cell system 100 according to the present embodiment. As shown in FIG. 2, the fuel cell system 100 includes a host controller (host ECU) 51, an overall controller (overall ECU) 52, and a plurality of individual controllers (individual ECUs) 53. Each of the controllers 51 to 53 is configured to include a computer having a CPU, a ROM, a RAM, and peripheral circuits. The overall controller 52 and the plurality of individual controllers 53 may be collectively referred to as a control unit 102.

[0022] The host controller 51 and the overall controller 52, and the overall controller 52 and the individual controllers 53 are communicably connected to each other. In particular, the overall controller 52 and the individual controllers 53 are communicably connected to each other via a pair of communication lines L11, L11 using a communication protocol such as CAN. Since the network is duplicated, the redundancy is high, and it is easy to maintain the continuity of communication between the overall controller 52 and the individual controllers 53.

[0023] The individual controller 53 is included in the unit system 101, and the individual controllers 53 are provided in the number corresponding to the number of the plurality of unit systems 101. Different from FIG. 1, FIG. 2 shows an example in which the fuel cell system 100 has four unit systems 101. Therefore, the fuel cell system 100 has four individual controllers 53. Note that the number of the individual controllers 53 may be other than four as long as it is plural.

[0024] The fuel cell system 100 according to the present embodiment is mounted on a vehicle. The host controller 51 calculates the power generation amount (required power generation amount) required by the vehicle. More specifically, the host controller 51 calculates the target drive torque of the drive motor based on the signal from the accelerator opening sensor that detects the opening of the accelerator pedal, and calculates the required power generation amount required for the drive motor to generate the target drive torque. Alternatively, the host controller 51 calculates the required power generation amount so that the remaining capacity of the battery becomes a predetermined value based on the signal from the battery sensor that detects the remaining capacity SOC of the battery.

[0025] The central controller 52 determines the amount of power generated for each unit system (individual power generation requirement) according to the required power generation. More specifically, the central controller 52 determines whether there is an abnormality (failure) in the unit system 101 based on the signals from the individual controllers 53, and determines the individual power generation requirement based on the determination result. For example, if an abnormality occurs in one of the four unit systems 101, the central controller 52 determines the individual power generation requirement so that the three unit systems 101 that are not abnormal share the required power generation. Furthermore, the central controller 52 estimates the degree of deterioration of the unit system 101 based on the signals from the individual controllers 53, and determines the individual power generation requirement based on the estimation result. Specifically, the central controller 52 determines the individual power generation requirement so that the unit system 101 with a small degree of deterioration (high efficiency) generates power preferentially.

[0026] The individual controller 53 determines whether there is an abnormality in the unit system 101 and estimates the degree of deterioration of the unit system 101 based on signals from temperature sensors, pressure sensors, etc., that detect the temperature and pressure of the fuel gas supply channel PA1, oxidizer gas supply channel, cooling medium supply channel, etc. The individual controller 53 then transmits the results of the abnormality determination and the estimated degree of deterioration to the main controller. Furthermore, based on commands from the main controller 52, the individual controller 53 controls the injectors 31 and other components so that the fuel cell stack 1 generates power according to the individually requested power generation amount.

[0027] The central controller 52 outputs control signals to multiple on-off valves 25 in response to commands from individual controllers 53, and opens and closes multiple on-off valves 25 simultaneously. More specifically, when the fuel cell system 100 is started up and a hydrogen retention request is output from the individual controller 53, the central controller 52 opens the on-off valves 25.

[0028] The main controller 52 starts up, for example, when the higher-level controller 51 is activated by turning on the ignition switch in the driver's seat, and then receives a start signal (start command) from the higher-level controller 51. After the main controller 52 starts up, it sends a start signal (start command) to the individual controllers 53. On the other hand, when the ignition switch is turned off, the main controller 52 sends a stop signal (stop command) to the individual controllers 53.

[0029] Figure 3 is a flowchart showing an example of the processing related to hydrogen retention requests performed by each individual controller 53. The processing shown in this flowchart starts when a start signal is sent from the main controller 52 to the individual controller 53 and is repeated at predetermined intervals until a stop signal is output to the individual controller 53. The main controller 52 continues to send start signals to the individual controller 53 until it receives an abnormality signal sent from the individual controller 53 when an abnormality (failure) occurs in the individual controller 53. This maintains the activated state of the individual controller 53. Note that in the initial state immediately after the start of the processing in Figure 3, the hydrogen retention request flag is zero.

[0030] First, in step S1, it is determined whether or not a start signal has been output from the main controller 52, that is, whether or not there is a start request. If no abnormal signal is sent from the individual controller 53, the main controller 52 continues to output start requests. In this case, step S1 is affirmed, and the process proceeds to step S2. In step S2, the hydrogen retention request flag is set to 1, and a hydrogen retention request is output. This hydrogen retention request is then sent to the main controller 52.

[0031] On the other hand, if step S1 is rejected due to an abnormal signal being transmitted from the individual controller 53, the process proceeds to step S3 to determine whether the hydrogen retention request flag is 1 or not. If it is confirmed in step S3, the process proceeds to step S4; if it is rejected, the process ends. In step S4, it is determined whether the fuel cell shutdown process has been completed. If an abnormality is detected in the unit system 101, the individual controller 53 performs the shutdown process. In the shutdown process, the individual controller 53 controls the valves for fuel gas, oxidizer gas, and cooling medium at predetermined timings, consumes the fuel gas remaining in the fuel cell stack, and then stops power generation in the fuel cell stack 1. Furthermore, oxidizer gas is forcibly circulated into the fuel cell stack by driving an air pump or the like to remove any remaining moisture in the fuel cell stack.

[0032] If the result in step S4 is positive, proceed to step S5; if it is negative, terminate the process. In step S5, the hydrogen retention request flag is set to 0, stopping the output of hydrogen retention requests. This stops the transmission of hydrogen retention requests to the main controller 52.

[0033] If an abnormality occurs in both of the pair of communication lines L11, L11, and communication between the main controller 52 and the individual controller 53 becomes impossible, the individual controller 53 cannot send an abnormality signal to the main controller 52. In this case, the main controller 52 treats the individual controller 53 as if there is no output of a hydrogen retention request. On the other hand, if an abnormality occurs in one of the pair of communication lines L11, L11, the main controller 52 and the individual controller 53 can communicate via the other line, and in this case, the individual controller 53 sends a hydrogen retention request to the main controller 52.

[0034] The operation of the individual controller 53 at startup will be explained in more detail. If there is no abnormality in the unit system 101, the individual controller 53 receives a startup signal and then sends a hydrogen retention request to the main controller 52 (step S2). On the other hand, if a failure occurs in the unit system 101 that would allow for a normal shutdown process (a process using fuel gas), making it impossible to generate electricity in the unit system 101, the individual controller 53 starts the shutdown process and sends an abnormality signal to the main controller 52 indicating that power generation is impossible. When the main controller 52 receives the abnormality signal, it stops sending startup signals to the individual controller 53. As a result, the individual controller 53 stops sending hydrogen retention requests to the main controller 52 after the shutdown process is completed (step S5).

[0035] On the other hand, if a hydrogen leak occurs in the fuel cell stack 1 or for other reasons that prevent normal shutdown procedures, the individual controller 53 performs a different shutdown procedure (emergency shutdown). In this case, the individual controller 53 shuts down the unit system 101 in a shorter time than usual, and then stops sending hydrogen retention requests to the main controller 52.

[0036] Figure 4 is a flowchart illustrating an example of processing performed by the main controller 52, particularly an example of processing related to opening the on-off valve 25 when the fuel cell system 100 is started. The processing shown in this flowchart starts after the main controller 52's startup process is completed and is repeated at predetermined intervals. In the initial state before the start of the processing shown in Figure 4, the on-off valve 25 is closed.

[0037] In step S11 of Figure 4, it is determined whether or not a hydrogen retention request has been received from at least one of the multiple individual controllers 53. If the answer in step S11 is affirmative, the process proceeds to step S12, where control signals are output to the multiple on-off valves 25, and the multiple on-off valves 25 are opened simultaneously. On the other hand, if the answer in step S12 is negative, the process proceeds to step S13, where the multiple on-off valves 25 are closed.

[0038] The main operation of the fuel cell system 100 according to this embodiment is summarized as follows: When the vehicle's ignition switch is turned on, the higher-level controller 51 starts up, and then the main controller 52 starts the startup process based on a command from the higher-level controller 51. After the startup process is completed, the main controller 52 sends a startup signal to a plurality of individual controllers 53. When an individual controller 53 receives a startup signal, it determines whether or not there is an abnormality in the unit system 101. If it is determined that there is no abnormality, it sends a hydrogen retention request to the main controller 52 (step S2).

[0039] When the central controller 52 receives a hydrogen retention request from at least one of the individual controllers 53, it simultaneously opens multiple on-off valves 25 (step S12). This enables the supply of fuel gas from the fuel gas storage unit 2 to the fuel gas supply unit 3. In this state, when the injector 31 is driven by a command from the individual controller 53, fuel gas is supplied to the fuel cell stack 1 via the fuel gas supply channel PA1, and power generation begins.

[0040] In this case, even if some of the multiple unit systems 101 malfunction, as long as all of the multiple unit systems 101 are functioning normally, a hydrogen retention request is output to the main controller 52, and the on-off valve 25 is opened. This allows for efficient power generation by the fuel cell. Furthermore, there is variation in the time it takes for the multiple individual controllers 53 to complete their startup processes, and therefore there is variation in the timing of outputting the hydrogen retention request flag after startup. In this regard, if all unit systems 101 are functioning normally, the main controller 52 commands the opening of the on-off valve 25 as soon as it receives a hydrogen retention request from the first individual controller 53 to start up. This makes it possible to supply fuel gas to the fuel cell stack 1 earlier, and to start power generation by the fuel cell earlier.

[0041] In contrast, if the system were to wait for hydrogen retention requests to be output from all individual controllers 53 before opening the on-off valve 25, the timing of opening the on-off valve 25 would be delayed, and it would likely take longer for the fuel cell to start generating electricity.

[0042] This embodiment can provide the following effects and advantages. (1) The fuel cell system 100 comprises a plurality of unit systems (fuel cells) 101, a fuel gas storage unit 2 in which fuel gas is stored, an on-off valve 25 positioned between each of the plurality of unit systems 101 and the fuel gas storage unit 2 (particularly the fuel gas tank 20) ​​to allow or block the flow of fuel gas through the fuel gas supply passage PA1, and a control unit 102 that opens the on-off valve 25 in response to an open valve command, i.e., a hydrogen retention request, output from each of the plurality of unit systems 101 (Figures 1 and 2). The control unit 102 (particularly the master controller 52) opens the on-off valve 25 when a hydrogen retention request is output from at least one of the plurality of unit systems 101, provided that all of the plurality of unit systems 101 are functioning normally. This allows the on-off valve 25 to be opened early when the fuel cell system 100 is started, and enables early power generation in the fuel cell system 100 having a plurality of fuel cells.

[0043] (2) The control unit 102 includes a master controller 52 that determines the required power generation amount for each of the multiple unit systems 101, and multiple individual controllers 53 that individually control each of the multiple unit systems 101 to generate power according to the required power generation amount determined by the master controller 52 (Figure 2). The master controller 52 determines whether or not hydrogen retention requests have been output from the multiple individual controllers 53, and when all of the multiple unit systems 101 are functioning normally, if a hydrogen retention request is output from at least one of the multiple individual controllers 53, it opens the on-off valve 25 (Figure 4). As a result, the master controller 52 consolidates the hydrogen retention requests output from the multiple individual controllers 53, thereby reducing the processing load.

[0044] (3) The main controller 52 opens the on-off valve 25 when a hydrogen retention request is output from at least one of the individual controllers 53, even if some of the multiple unit systems 101 are malfunctioning (Figure 4). This allows power generation to start even if some of the multiple unit systems 101 are malfunctioning.

[0045] (4) Each of the multiple individual controllers 53 is connected to the main controller 52 via a pair of communication lines L11, L11, and each of the multiple individual controllers 53 is configured to output a hydrogen retention request via each of the pair of communication lines L11, L11. This ensures that even if an abnormality occurs in one of the communication lines L11, L11, a hydrogen retention request can still be output via the other communication line L11.

[0046] (5) When an abnormality occurs in both of the pair of communication lines L11, L11, the main controller 52 determines that no hydrogen retention request is output from the individual controllers 53 connected to the pair of communication lines L11, L11 where the abnormality occurred. As a result, even if there is an individual controller 53 that cannot communicate with the main controller 52, the main controller 52 can receive a hydrogen retention request output from another individual controller 53, open the on / off valve 25 and start power generation.

[0047] The above embodiment can be modified into various forms. Several modifications are described below. In the above embodiment, an electromagnetic on-off valve 25 is placed between the fuel gas tank 20 and the supply manifold 22, and the flow of fuel gas through the fuel gas supply passage PA1 is allowed or blocked by opening and closing the on-off valve 25, but the configuration of the valve device is not limited to this. Furthermore, the valve device may be placed in other locations as long as it is located in the fuel gas supply passage from the fuel gas storage unit 2 (fuel gas tank 20) ​​to multiple fuel cells.

[0048] In the above embodiment, the control unit 102 is configured with a master controller 52 and individual controllers 53, and the master controller 52 (master control unit) commands the opening of the on-off valve 25 in response to hydrogen retention requests (valve opening commands) output from each of the multiple fuel cells (unit systems 101). However, the configuration of the control unit is not limited to this. For example, a specific individual controller 53 among the multiple individual controllers 53 (individual control units) may have the function of the master controller 52.

[0049] In the above embodiment, the main controller 52 determined the individual power generation amounts so that the requested power generation amount requested by the higher-level controller 51 would be shared among the normal unit systems 101. In this case, the individual power generation amounts may be determined so that all of the multiple normal unit systems 101 generate power, or they may be determined so that some of the unit systems 101 generate power. In the above embodiment, an abnormal signal was output from the malfunctioning unit system 101, but if the unit system 101 can generate power in response to a command from the main controller 52 even while malfunctioning, the abnormal signal may not be output from the unit system 101. In other words, even if a unit system 101 is malfunctioning, depending on the nature of the malfunction, the unit system 101 may be treated the same as a normal unit system 101 and allowed to generate power.

[0050] In the above embodiment, an example of applying the fuel cell system 100 to a fuel cell vehicle was described, but the fuel cell system of the present invention can be applied to various mobile devices having multiple fuel cells, and can also be applied to devices other than mobile devices.

[0051] The above description is merely an example, and the present invention is not limited by the embodiments and modifications described above, as long as the features of the present invention are not impaired. It is also possible to arbitrarily combine one or more of the above embodiments and modifications, and to combine modifications with each other. [Explanation of Symbols]

[0052] 2 Fuel gas storage unit, 3 Fuel gas supply unit, 25 On / off valve, 52 Main controller, 53 Individual controllers, 100 Fuel cell system, 101 Unit system, 102 Control unit, PA1 Fuel gas supply channel, L11 Communication line

Claims

1. Multiple fuel cells, A fuel gas storage section where fuel gas is stored, A valve device is positioned between each of the fuel gas supply passages of the plurality of fuel cells and the fuel gas storage section, and allows or blocks the flow of fuel gas through the fuel gas supply passage. The system includes a control unit that opens the valve device in response to an open valve command output from each of the plurality of fuel cells, The fuel cell system is characterized in that the control unit opens the valve device when an open valve command is output from at least one of the fuel cells, while all of the plurality of fuel cells are functioning normally.

2. In the fuel cell system according to claim 1, The control unit comprises a central control unit that determines the required power generation amount for each of the plurality of fuel cells, and a plurality of individual control units that individually control each of the plurality of fuel cells to generate power according to the required power generation amount determined by the central control unit. The fuel cell system is characterized in that the central control unit determines whether or not the valve open command has been output from the plurality of individual control units, and when all of the plurality of fuel cells are functioning normally, it opens the valve device when the valve open command is output from at least one of the plurality of individual control units.

3. In the fuel cell system according to claim 2, The fuel cell system is characterized in that the central control unit opens the valve device when the valve opening command is output from at least one of the individual control units, even if some of the multiple fuel cells are malfunctioning.

4. In the fuel cell system according to claim 2 or 3, A fuel cell system characterized in that each of the plurality of individual control units is connected to the central control unit via the plurality of communication lines so as to be communicable, and the valve opening command is output from each of the plurality of individual control units via each of the plurality of communication lines.

5. In the fuel cell system according to claim 4, The fuel cell system is characterized in that, when an abnormality occurs in all of the multiple communication lines, the central control unit determines that no valve opening command will be output from the individual control units connected to the multiple communication lines where the abnormality occurred.

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