Fuel cell system and operation method thereof

Abstract

The present invention aims to provide a fuel cell system that can quickly start up the system, simplify the system structure, and achieve low costs. To solve the above problems, the present invention provides a fuel cell system comprising a first power supply system having a plurality of fuel cell stacks, an oxidant gas flow channel that distributes and supplies oxidant gas to each of the fuel cell stacks, and an air supply unit provided on each fuel cell stack. A battery is electrically connected to the air supply unit at least in the fuel cell stack connected to the oxidant gas flow channel on the upstream side of the plurality of fuel cell stacks.

Description

Technical Field

[0001] The present invention relates to a fuel cell system and an operating method thereof. Background Art

[0002] Fuel cell systems using fuel cells are known. For example, a fuel cell system consists of a fuel cell stack, which has a stack structure consisting of dozens to hundreds of stacked cells. Hydrogen gas is supplied as a reactant gas to the anode electrode of the fuel cell stack, and oxygen-containing air is supplied as a reactant gas to the cathode electrode. This generates electricity through an electrochemical reaction.

[0003] When using a fuel cell system as, for example, an emergency power generation system, it is required to quickly start the system. As a technology related to the startability of a fuel cell system, for example, the following technology is known: in a fuel cell power generation device having multiple fuel cells of different capacities, a burner that burns hydrogen is installed in the smaller fuel cells, and a warm-up operation is performed using the combustion gas, thereby shortening the system startup time during low-temperature startup (for example, see Patent Document 1).

[0004] [Prior Art Literature]

[0005] (Patent Document)

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-39524 Summary of the Invention

[0007] [Problems to be solved by the invention]

[0008] The technology disclosed in Patent Document 1 requires a burner for warm-up operation, which complicates the system structure. In addition, when a fuel cell system is composed of multiple fuel cells, it may not always be necessary to use fuel cells with different capacities.

[0009] The present invention has been made in view of the above, and an object of the present invention is to provide a fuel cell system that can quickly start the system and simplify the system structure to achieve cost reduction.

[0010] [Technical means to solve the problem]

[0011] (1) The present invention relates to a fuel cell system comprising a first power supply system having a plurality of fuel cell stacks, an oxidant gas flow channel for distributing and supplying oxidant gas to each of the aforementioned fuel cell stacks, and an air supply unit provided on each fuel cell stack, wherein, among the plurality of aforementioned fuel cell stacks, at least in the fuel cell stack connected to the aforementioned oxidant gas flow channel at the most upstream side, a battery is electrically connected to the aforementioned air supply unit.

[0012] According to the invention of (1), a fuel cell system can be provided which can start the system quickly and simplify the system structure to achieve cost reduction.

[0013] (2) The fuel cell system according to (1) further includes a second power supply system having the same structure as the first power supply system, wherein the battery is electrically connected to the air supply unit of at least one of the plurality of fuel cell stacks constituting the second power supply system and connected to the oxidant gas flow path at the most upstream side.

[0014] According to the invention of (2), a plurality of power supply systems can be started using a single storage battery, and the configuration of the system can be simplified.

[0015] (3) The fuel cell system according to (1) further includes a hydrogen flow passage for supplying hydrogen to each of the aforementioned fuel cell stacks, the fuel cell stack connected to the aforementioned oxidant gas flow passage at the most upstream side is the fuel cell stack connected to the aforementioned hydrogen flow passage at the most upstream side, and a first opening and closing valve capable of opening and closing the aforementioned hydrogen flow passage is provided between the fuel cell stack connected to the aforementioned hydrogen flow passage at the most upstream side and the other fuel cell stacks.

[0016] According to the invention of (3), the fuel cell system can be started more quickly.

[0017] (4) The fuel cell system according to (3) further includes a second power supply system having the same structure as the first power supply system, wherein a distribution unit for distributing the hydrogen to the first power supply system and the second power supply system is provided on the hydrogen flow passage, and a second on-off valve capable of opening and closing the hydrogen flow passage is provided on the downstream side of the distribution unit in the hydrogen flow passage and on the upstream side of the fuel cell stack of the second power supply system connected to the hydrogen flow passage at the most upstream side.

[0018] According to the invention of (4), the fuel cell system can be started more quickly.

[0019] (5) The fuel cell system according to (3) further includes a second power supply system having the same structure as the first power supply system, wherein a first opening and closing valve capable of opening and closing the hydrogen flow passage is provided between the fuel cell stack located at the most upstream side of the hydrogen flow passage and other fuel cell stacks in the first power supply system, and between the fuel cell stack located at the most upstream side of the hydrogen flow passage and other fuel cell stacks in the second power supply system.

[0020] According to the invention of (5), the fuel cell system can be started more quickly.

[0021] (6) A method for operating a fuel cell system, which uses the fuel cell system of (1) or (2), uses the aforementioned battery to start the fuel cell stack connected to the aforementioned oxidant gas flow channel at the upstream side, and supplies the electricity obtained by the power generation of the fuel cell stack to the aforementioned air supply unit of the other fuel cell stacks of the aforementioned fuel cell system, thereby starting the aforementioned other fuel cell stacks.

[0022] According to the invention of (6), the configuration of the fuel cell system can be simplified.

[0023] (7) A method for operating a fuel cell system, which uses the fuel cell system of (2), uses the aforementioned battery to start the fuel cell stack in the aforementioned first power supply system that is connected to the aforementioned oxidant gas flow channel at the upstream side, and supplies the power obtained by the power generation of the fuel cell stack to the air supply unit of the other fuel cell stack in the fuel cell stack constituting the aforementioned second power supply system that is connected to the aforementioned oxidant gas flow channel at the upstream side, thereby starting the aforementioned other fuel cell stack.

[0024] According to the invention of (7), a single storage battery can be used to start a plurality of power supply systems, and the configuration of the system can be simplified.

[0025] (8) A method for operating a fuel cell system, which uses the fuel cell system of (1) or (2), has a stack information acquisition unit for acquiring fuel cell stack information including degradation information and / or operating history of each fuel cell stack, electrically connects the aforementioned battery to the aforementioned air supply unit provided on at least two or more fuel cell stacks, and determines the fuel cell stack to be supplied with electricity from the aforementioned battery based on the aforementioned degradation information and / or the aforementioned operating history acquired by the aforementioned stack information acquisition unit.

[0026] According to the invention of (8), the degradation state of the fuel cell system can be made uniform, and the durability of the fuel cell system can be improved. In addition, the fuel cell system can be started up quickly.

[0027] (9) A method for operating a fuel cell system, which uses the fuel cell system of (3), and has a startup preparation information acquisition unit for acquiring startup preparation completion information of a fuel cell stack connected to the aforementioned oxidant gas flow channel on the most upstream side, and by acquiring the aforementioned startup preparation completion information, the aforementioned first on-off valve is switched from a closed state of the aforementioned hydrogen flow channel to an open state.

[0028] According to the invention of (9), after starting one fuel cell stack, other fuel cell stacks can be quickly started.

[0029] (10) A method for operating a fuel cell system, which uses the fuel cell system of (3), and has a power generation acquisition unit for acquiring the power generation of the fuel cell stack connected to the aforementioned oxidant gas flow channel at the upstream side, and when the aforementioned power generation meets specific conditions, the aforementioned first on-off valve switches from a closed state of the aforementioned hydrogen flow channel to an open state.

[0030] According to the invention of (10), after starting one fuel cell stack, other fuel cell stacks can be quickly started.

[0031] (11) A method for operating a fuel cell system, which uses the fuel cell system of (4), and has a startup preparation information acquisition unit for acquiring startup preparation completion information of the aforementioned first power supply system, by acquiring the aforementioned startup preparation completion information, the aforementioned second on-off valve switches from a closed state of the aforementioned hydrogen flow channel to an open state.

[0032] According to the invention of (11), the fuel cell system can be started more quickly, and after starting one fuel cell stack, other fuel cell stacks can be started quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a diagram showing the structure of a fuel cell system according to a first embodiment of the present invention.

[0034] Figure 2 It is a diagram showing the structure of a fuel cell system according to a second embodiment of the present invention.

[0035] Figure 3 It is a diagram showing the structure of a fuel cell system according to a third embodiment of the present invention. DETAILED DESCRIPTION

[0036] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiment, and can be implemented by appropriately adding modifications within the scope of the purpose of the present invention.

[0037] First Implementation Method

[0038] Fuel Cell System

[0039] Figure 1 This figure schematically illustrates the structure of a fuel cell system according to this embodiment. The fuel cell system 1 according to this embodiment comprises a first power supply system G1, a second power supply system G2, and a pressurized hydrogen storage tank 3. The number of power supply systems comprising the fuel cell system 1 is not particularly limited, and may be three or more.

[0040] (First Power Supply System, Second Power Supply System)

[0041] [Fuel cell stack]

[0042] The first power supply system G1 and the second power supply system G2 are respectively composed of a plurality of fuel cell stacks S1 to S5, and S6 to S10. The number of fuel cell stacks constituting each power supply system is not particularly limited to the above description. The structure of each fuel cell stack is not particularly limited, for example, it has a stack structure formed by stacking dozens to hundreds of monomers. Each fuel cell monomer is composed of a membrane electrode assembly (MEA) sandwiched by a diaphragm. The membrane electrode assembly is composed of, for example, two electrodes, an anode electrode (cathode) and a cathode electrode (anode), and a solid polymer electrolyte membrane sandwiched by these electrodes. After hydrogen is supplied to the anode flow channel formed on the anode electrode side, and air containing oxygen as an oxidant gas is supplied to the cathode flow channel formed on the cathode electrode side, electricity is generated by their electrochemical reaction. The generated electricity is output to an external load O.

[0043] [Oxidant gas flow path]

[0044] The first power supply system G1 and the second power supply system G2 have supply lines L11 and L21 as oxidant gas flow paths for distributing and supplying oxidant gas to the plurality of fuel cell stacks constituting each power supply system, and exhaust lines L12 and L22 for exhausting the oxidant gas. In this embodiment, the supply lines L11 and L21, and the exhaust lines L12 and L22 are independent flow paths. The supply lines and exhaust lines are as follows: Figure 1 As shown, each has a tournament structure formed by merging flow channels connected to multiple fuel cell stacks. Oxidant gas is supplied to each fuel cell stack via supply lines L11 and L21 by an air pump (AP) as an air supply unit installed in each fuel cell stack. The oxidant gas used for the electrochemical reaction in each fuel cell stack is discharged to the outside via exhaust lines L12 and L22. Air purification devices 11 and 21 can also be installed upstream of the supply lines L11 and L21.

[0045] Among the multiple fuel cell stacks constituting the first power supply system G1, an intelligent power unit (IPU) 10 serving as a battery is electrically connected to the air pump 12 of at least the fuel cell stack S1 connected to the supply line L11 serving as the oxidant gas flow path at the most upstream side. By operating the switch SW1 provided between the IPU 10 and the air pump 12, power can be supplied from the IPU 10 to the air pump 12. Thus, the IPU 10 is configured to supply power to the air pump 12 of the fuel cell stack S1 to which the oxidant gas flows first, thereby enabling the fuel cell system 1 to be quickly started. The IPU 10 or the fuel cell stack S1 is as follows: Figure 1 As shown, power can also be supplied via switch SW2 to the air pump of fuel cell stack S6, which is connected to the supply line L21 serving as the oxidant gas flow path at the most upstream side among the multiple fuel cell stacks constituting the second power supply system G2. This allows the second power supply system G2 to be activated using power generated by the IPU 10 or the fuel cell stack S1.

[0046] The fuel cell stack S1, the other fuel cell stacks S2 to S5 constituting the first power supply system G1 and the air pumps they have are connected to the fuel cell stack S1. Figure 1 The circuit E1 shown by the dashed line in the middle is electrically connected. This allows the power generated by fuel cell stack S1 to be supplied to the air pumps of other fuel cell stacks. This eliminates the need for an IPU for each fuel cell stack, simplifying the system architecture. Similarly, fuel cell stack S6 can be electrically connected to the other fuel cell stacks S7 to S10 that constitute the second power supply system G2, as well as their respective air pumps.

[0047] The fuel cell stacks S1 to S5 constituting the first power supply system G1 and the fuel cell stacks S6 to S10 constituting the second power supply system G2 and the air pumps therein may also be arranged as follows: Figure 1 As shown, they are electrically connected via the switch SW3. This enables an operation method in which each fuel cell stack constituting the first power supply system G1 is activated and then each fuel cell stack constituting the second power supply system G2 is activated.

[0048] [Hydrogen flow channel]

[0049] The first power supply system G1 and the second power supply system G2 have a hydrogen flow channel L3 that distributes and supplies hydrogen to the multiple fuel cell stacks that constitute each power supply system. In this embodiment, the hydrogen flow channel L3 is a common flow channel having a distribution unit C that supplies hydrogen to the first power supply system G1 and the second power supply system G2. Figure 1As shown, each fuel cell stack has a championship structure formed by merging flow channels connecting multiple fuel cell stacks. A pressurized hydrogen tank 3 is connected to the upstream side of hydrogen flow channel L3. Hydrogen gas supplied from the pressurized hydrogen tank 3 to each fuel cell stack is supplied to each fuel cell stack by a pump 13 installed in each fuel cell stack.

[0050] Among the multiple fuel cell stacks constituting the first power supply system G1, the fuel cell stack S1 connected most upstream to the supply line L11 serving as the oxidant gas flow path is preferably also the fuel cell stack connected most upstream to the hydrogen flow path L3. In other words, the oxidant gas and hydrogen gas are preferably supplied first to the fuel cell stack S1, which is one of the multiple fuel cell stacks constituting the first power supply system G1.

[0051] In addition to the above, the fuel cell system 1 may also have a stack information acquisition unit, which acquires fuel cell stack information including degradation information and / or operating history of each fuel cell stack. In addition, the fuel cell system 1 may also have a startup preparation information acquisition unit, which acquires startup preparation completion information of the fuel cell stack S1 connected to the oxidant gas flow channel at the upstream side. The startup preparation completion information is obtained, for example, by providing a hydrogen concentration sensor on the fuel cell stack and measuring or estimating the hydrogen concentration in the fuel cell monomer. In addition, the fuel cell system 1 may also have a power generation acquisition unit that acquires the power generation of the fuel cell stack S1.

[0052] <Operation Method of Fuel Cell System>

[0053] The fuel cell system 1 operates by supplying power from the IPU 10 to the air pump 12 of fuel cell stack S1, thereby supplying oxidant gas to fuel cell stack S1 and hydrogen gas to fuel cell stack S1 via the hydrogen flow path L3. This prioritizes and quickly activates fuel cell stack S1. Subsequently, the power generated by fuel cell stack S1 is supplied to the air pumps of the other fuel cell stacks S2 to S5, activating the other fuel cell stacks S2 to S5. This allows for rapid startup of the fuel cell system 1, and the number of fuel cell stacks to be activated is then determined based on the power required.

[0054] The fuel cell system 1 can also be operated by, after starting the fuel cell stack S1, supplying the electricity generated by the fuel cell stack S1 to the air pump of the fuel cell stack S6 connected to the supply line L21 serving as the oxidant gas flow path at the most upstream side among the multiple fuel cell stacks constituting the second power supply system G2, thereby starting the fuel cell stack S6. Alternatively, after starting the fuel cell stack S6, the electricity generated by the fuel cell stack S6 can be supplied to the air pumps of the other fuel cell stacks S7 to S10 constituting the second power supply system G2, thereby starting the other fuel cell stacks S7 to S10. Alternatively, after starting the first power supply system G1, the electricity generated by the first power supply system can be used to start each fuel cell stack constituting the second power supply system G2. In this manner, the number of fuel cell stacks to be started can be determined based on the required power.

[0055] Second Implementation Method

[0056] Fuel Cell System

[0057] Next, a schematic diagram showing the configuration of the fuel cell system 1a is used. Figure 2 In the following description, the same structures as those in the first embodiment are sometimes denoted by the same reference numerals in the drawings, and their descriptions are sometimes omitted.

[0058] [Storage Battery (IPU)]

[0059] like Figure 2 As shown, an IPU 10a serving as a battery is electrically connected to the air pumps of the multiple fuel cell stacks S1 to S5 constituting the first power supply system G1 and the multiple fuel cell stacks S6 to S10 constituting the second power supply system G2. The IPU 10a only needs to be connected to two or more of the above-mentioned air pumps, but is preferably connected to the air pumps of all the fuel cell stacks. By operating the switch SW provided between the IPU 10a and each air pump, power can be supplied from the IPU 10a to each air pump. The fuel cell system 1a preferably has a stack information acquisition unit (not shown), which acquires fuel cell stack information including degradation information and / or operating history of each fuel cell stack.

[0060] <Operation Method of Fuel Cell System>

[0061] The operating method of the fuel cell system 1a is to determine the priority of the fuel cell stacks to be supplied with power by the IPU 10a based on the degradation information and / or operation history obtained by the stack information acquisition unit. Specifically, for example, based on the total power generation time of each fuel cell stack pre-stored in the storage device, the degradation degree and / or operation history of each fuel cell stack are compared, and the priority of the fuel cell stacks to be supplied with power by the IPU 10a is determined in order starting from the fuel cell stack with the lowest degree of degradation. In this way, the degradation degree of each fuel cell stack can be made uniform, so the durability of the fuel cell system 1 can be improved. In addition to the above, the fuel cell stack with the lowest degree of degradation can also be set as the fuel cell stack with the highest priority for power supply by the IPU 10a. In this way, the startup time of the fuel cell system 1 can be minimized.

[0062] Third Implementation Method

[0063] Fuel Cell System

[0064] Next, a schematic diagram showing the configuration of the fuel cell system 1b is used. Figure 3 , a fuel cell system 1b according to a third embodiment will be described.

[0065] [Hydrogen flow channel]

[0066] In the hydrogen flow passage L3 of this embodiment, a first on-off valve V1 capable of opening and closing the hydrogen flow passage L3 is provided between the fuel cell stack S1 connected to the most upstream side of the hydrogen flow passage L3 and the other fuel cell stacks S2 to S5 in the first power supply system G1. Similarly, a first on-off valve V2 capable of opening and closing the hydrogen flow passage L3 is provided between the fuel cell stack S6 connected to the most upstream side of the hydrogen flow passage L3 and the other fuel cell stacks S7 to S10 in the second power supply system G2.

[0067] In addition to the above, the hydrogen flow channel L3 of this embodiment is further provided with a second opening and closing valve V3 capable of opening and closing the hydrogen flow channel L3 on the downstream side of the distribution part C in the hydrogen flow channel L3 and on the upstream side of the fuel cell stack S6 of the second power supply system G2 connected to the hydrogen flow channel L3 at the upstream side.

[0068] The structures of the first on-off valves V1 and V2, and the second on-off valve V3 of this embodiment can be applied not only to the hydrogen flow passage L3, but also to the supply lines L11 and L21 serving as oxidant flow passages, and the coolant flow passages through which the coolant for cooling the fuel cell stack circulates. Similar to the hydrogen flow passage L3, these oxidant flow passages and coolant flow passages have a championship structure formed by merging the flow passages communicating with multiple fuel cell stacks.

[0069] The fuel cell system 1b preferably has at least one of a startup preparation information acquisition unit (not shown) for acquiring startup preparation completion information of the fuel cell stack S1 connected to the oxidant gas flow channel at the most upstream side, and a power generation acquisition unit (not shown) for acquiring the power generation of the fuel cell stack S1.

[0070] <Operation Method of Fuel Cell System>

[0071] The fuel cell system 1b operates by supplying power from the IPU 10 to the air pump 12 of the fuel cell stack S1, thereby supplying oxidant gas to the fuel cell stack S1. Furthermore, with the first on-off valves V1 and V2 and the second on-off valve V3 closed, hydrogen is supplied to the fuel cell stack S1 via the hydrogen flow passage L3, giving priority to starting up the fuel cell stack S1. This stops the hydrogen supply to the other fuel cell stacks, allowing hydrogen to be rapidly filled through the hydrogen flow passage L3 leading to the fuel cell stack S1. Consequently, the fuel cell stack S1 can be started up more quickly.

[0072] The fuel cell system 1b operates by switching the first on-off valve V1 from a closed state to an open state after starting the fuel cell stack S1, based on at least one of the following: information indicating completion of start-up preparation obtained by the start-up preparation information acquisition unit and the power generation of the fuel cell stack S1 obtained by the power generation acquisition unit. Specifically, when specific conditions are met, such as when the hydrogen concentration within the fuel cell unit or the power generation of the fuel cell stack S1 exceeds a predetermined threshold, the first on-off valve V1 is switched from a closed state to an open state. Hydrogen is then supplied to the other fuel cell stacks S2 to S5 via the hydrogen flow channel L3. This allows the other fuel cell stacks S2 to S5 to be quickly started after starting the fuel cell stack S1.

[0073] In addition to the above, the operating method of the fuel cell system 1b can also apply the conditions for switching the first on-off valve V1 from a closed state to an open state to the second on-off valve V3. This allows the fuel cell stack S6 in the second power supply system to be quickly started after the fuel cell stack S1 is started. Furthermore, the startup state of the fuel cell stack S6 can be confirmed based on information such as power generation, and the first on-off valves V1 and V2 can be switched from a closed state to an open state. This allows other fuel cell stacks other than the fuel cell stacks S1 and S6 to be quickly started.

[0074] When a first on-off valve and a second on-off valve are provided in the oxidant flow channel and the refrigerant flow channel, the first on-off valve and the second on-off valve provided in the oxidant flow channel and the refrigerant flow channel can be operated at the same time as the first on-off valve and the second on-off valve in the hydrogen flow channel L3, or they can be operated independently. For example, the first on-off valve and the second on-off valve can be operated so that hydrogen is first circulated into the hydrogen flow channel L3 before the oxidant gas and the refrigerant are respectively circulated into the oxidant flow channel and the refrigerant flow channel.

[0075] While preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments and can be modified as appropriate. For example, the structure of the hydrogen flow passage L3 having the first on-off valve and the second on-off valve of the third embodiment can be combined with the fuel cell system of the second embodiment.

[0076] Reference numerals

[0077] 1.1a, 1b: Fuel cell system

[0078] 10, 10a: IPU (battery)

[0079] 12: Air pump (air supply unit)

[0080] S1-S10: fuel cell stack

[0081] L11, L21: Supply pipeline (oxidant gas flow channel)

[0082] L3: Hydrogen flow channel

[0083] G1: First power supply system

[0084] G2: Second power supply system

[0085] V1, V2: First opening and closing valve

[0086] V3: Second on-off valve

Claims

1. A fuel cell system comprising a first power supply system, the first power supply system comprising a plurality of fuel cell stacks, an oxidant gas flow channel for distributing and supplying oxidant gas to each of the fuel cell stacks, an air supply unit provided on each fuel cell stack, and a hydrogen flow channel for supplying hydrogen gas to each of the fuel cell stacks. Among the plurality of fuel cell stacks, at least in the fuel cell stack connected to the oxidant gas flow path on the most upstream side, a battery is electrically connected to the gas supply unit. The fuel cell stack connected to the oxidant gas flow path on the most upstream side is the fuel cell stack connected to the hydrogen flow path on the most upstream side. The hydrogen flow channel has a championship structure, which is composed of flow channels respectively connected to the plurality of fuel cell stacks and a flow channel formed by merging the flow channels connected to the plurality of fuel cell stacks. In the merged flow channel, a first opening and closing valve capable of opening and closing the hydrogen flow channel is provided between the fuel cell stack connected to the hydrogen flow channel at the most upstream side and the other fuel cell stacks. The first on-off valve is in a closed position when the fuel cell system is started, and can restrict the flow of hydrogen gas to the fuel cell stack further downstream than the fuel cell stack connected to the most upstream side of the hydrogen flow path.

2. The fuel cell system according to claim 1, further comprising a second power supply system having the same structure as the first power supply system. The battery is electrically connected to the air supply unit of at least a fuel cell stack connected to the oxidant gas flow path on the most upstream side among the plurality of fuel cell stacks constituting the second power supply system.

3. The fuel cell system according to claim 1, further comprising a second power supply system having the same structure as the first power supply system. A distribution unit for distributing the hydrogen to the first power supply system and the second power supply system is provided on the hydrogen flow channel. A second on-off valve capable of opening and closing the hydrogen flow passage is provided downstream of the distribution portion in the hydrogen flow passage and upstream of the fuel cell stack connected to the hydrogen flow passage of the second power supply system at the most upstream side.

4. The fuel cell system according to claim 1, further comprising a second power supply system having the same structure as the first power supply system. A first on-off valve capable of opening and closing the hydrogen flow passage is provided between the fuel cell stack located at the most upstream side of the hydrogen flow passage in the first power supply system and other fuel cell stacks, and between the fuel cell stack located at the most upstream side of the hydrogen flow passage and other fuel cell stacks in the second power supply system.

5. A method for operating a fuel cell system, using the fuel cell system according to claim 1, Using the battery, the fuel cell stack connected to the oxidant gas flow path at the most upstream side is started, and The electric power obtained by the power generation of the fuel cell stack is supplied to the air supply unit of the other fuel cell stack of the fuel cell system, thereby starting the other fuel cell stack.

6. A method for operating a fuel cell system, using the fuel cell system according to claim 2, Using the aforementioned battery, the fuel cell stack connected to the aforementioned oxidant gas flow channel at the most upstream side in the aforementioned first power supply system is started, and the power obtained by the power generation of the fuel cell stack is supplied to the air supply unit of the other fuel cell stack connected to the aforementioned oxidant gas flow channel at the most upstream side in the fuel cell stack constituting the aforementioned second power supply system, thereby starting the aforementioned other fuel cell stack.

7. A method for operating a fuel cell system, using the fuel cell system according to claim 1, A stack information acquisition unit is provided for acquiring fuel cell stack information including degradation degree information and / or operation history of each fuel cell stack. The battery is electrically connected to the air supply unit provided on at least two fuel cell stacks, and the fuel cell stack to be supplied with power from the battery is determined based on the degradation information and / or the operation history acquired by the stack information acquisition unit.

8. A method for operating a fuel cell system, using the fuel cell system according to claim 1, A startup preparation information acquisition unit is provided to acquire startup preparation completion information of a fuel cell stack connected to the oxidant gas flow path at the most upstream side. By acquiring the startup preparation completion information, the first on-off valve is switched from a closed state to an open state of the hydrogen flow passage.

9. A method for operating a fuel cell system, using the fuel cell system according to claim 1, A power generation amount acquisition unit is provided to acquire the power generation amount of the fuel cell stack connected to the oxidant gas flow channel at the most upstream side. When the power generation amount satisfies a specific condition, the first on-off valve switches from a closed state to an open state of the hydrogen flow passage.

10. A method for operating a fuel cell system, using the fuel cell system according to claim 3, A startup preparation information acquisition unit is provided to acquire startup preparation completion information of the first power supply system. By acquiring the startup preparation completion information, the second on-off valve is switched from a closed state of the hydrogen flow passage to an open state.

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