Fuel cell system and aircraft

Abstract

The present invention provides a fuel cell system and an aircraft. Even when an abnormality occurs in the power generation of the fuel cell during the flight of the aircraft, the fuel cell system can stabilize the output of the fuel cell for a specified time, thereby extending the time during which the aircraft can fly stably. The fuel cell system is a fuel cell system for an aircraft, and is characterized in that the fuel cell system includes a fuel cell, a fuel gas system for supplying fuel gas to the fuel cell, a potential sensor, and a control unit. The fuel gas system includes a fuel gas supply unit. The control unit determines whether the potential of the fuel cell measured by the potential sensor is a reverse potential. When it is determined that the potential of the fuel cell is a reverse potential, the control unit increases the supply amount of the fuel gas from the fuel gas supply unit to the fuel cell.

Description

Technical Field

[0001] The present disclosure relates to a fuel cell system and an aircraft. Background Art

[0002] A fuel cell (FC) is a power generation device composed of a single cell (hereinafter, there are cases where it is described as a unit) or a fuel cell stack formed by stacking a plurality of single cells (hereinafter, there are cases where it is only described as a stack), and extracts electrical energy through an electrochemical reaction between a fuel gas such as hydrogen and an oxidant gas such as oxygen. In addition, in practice, the fuel gas and oxidant gas supplied to the fuel cell are mostly mixtures with gases that do not contribute to oxidation and reduction. In particular, the oxidant gas is often air containing oxygen.

[0003] In addition, hereinafter, there are also cases where the fuel gas and the oxidant gas are not particularly distinguished and are simply referred to as "reaction gas" or "gas". In addition, there are cases where both a single cell and a fuel cell stack formed by stacking single cells are called a fuel cell.

[0004] Various studies have been conducted on fuel cells.

[0005] For example, Patent Document 1 discloses an aircraft equipped with a fuel cell.

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2017-081559

[0007] Research has been conducted on the self-diagnosis function (on-board diagnostic function (OBD)) of a fuel cell system mounted on an aircraft.

[0008] For a fuel cell, if the supply amount of the fuel gas is insufficient, the catalyst reacts, and there is a case where the potential of the fuel cell becomes a reverse potential.

[0009] When the potential of the fuel cell becomes a reverse potential during the flight of the aircraft due to, for example, insufficient supply of the fuel gas to the fuel cell, it is necessary to perform operations such as restricting the output of the fuel cell, and thus the flight of the aircraft becomes unstable. Summary of the Invention

[0010] The present disclosure has been made in view of the above actual situation, and its main object is to provide a fuel cell system that can keep the output of the fuel cell stable and continuous for a specified time even when an abnormality occurs in the power generation of the fuel cell during the flight of the aircraft, thereby extending the time during which the aircraft can fly stably.

[0011] The fuel cell system of the present disclosure is a fuel cell system for an aircraft, and is characterized in that the fuel cell system has: a fuel cell; a fuel gas system that supplies fuel gas to the fuel cell; a potential sensor; and a control unit. The fuel gas system has a fuel gas supply unit. The control unit determines whether the potential of the fuel cell measured by the potential sensor is a reverse potential. When it is determined that the potential of the fuel cell is a reverse potential, the control unit increases the supply amount of the fuel gas from the fuel gas supply unit to the fuel cell.

[0012] It may also be configured as follows: Based on the fuel cell system of the present disclosure, the control unit monitors the potential of the fuel cell and records the cumulative time of the state in which the potential of the fuel cell is a reverse potential. When it is determined that the potential of the fuel cell is a reverse potential, the control unit determines whether the cumulative time is less than a specified time. When it is determined that the cumulative time is less than the specified time, the control unit increases the supply amount of the fuel gas from the fuel gas supply unit to the fuel cell.

[0013] The aircraft of the present disclosure is equipped with the above fuel cell system.

[0014] According to the fuel cell system of the present disclosure, even when an abnormality occurs in the power generation of the fuel cell during the flight of the aircraft, the output of the fuel cell can be stabilized and continued for a specified time, thereby extending the time during which the aircraft can fly stably. Description of the Drawings

[0015] Figure 1 It is a schematic structural diagram showing an example of the fuel cell system of the present disclosure.

[0016] Figure 2 It is a flowchart showing an example of the control of the fuel cell system of the present disclosure.

[0017] Figure 3 It is a flowchart showing another example of the control of the fuel cell system of the present disclosure.

[0018] Description of Reference Numerals

[0019] 10... Fuel cell; 20... Fuel gas supply unit; 21... Fuel gas supply flow path; 22... Fuel exhaust gas discharge flow path; 23... Exhaust and drain valve; 24... Gas-liquid separator; 25... Circulation flow path; 26... Ejector; 50... Control unit; 60... Potential sensor; 100... Fuel cell system. Detailed Description of the Invention

[0020] The fuel cell system of the present disclosure is a fuel cell system for an aircraft, characterized in that the fuel cell system includes: a fuel cell; a fuel gas system that supplies fuel gas to the fuel cell; a potential sensor; and a control unit. The fuel gas system includes a fuel gas supply unit. The control unit determines whether the potential of the fuel cell measured by the potential sensor is a reverse potential. When it is determined that the potential of the fuel cell is a reverse potential, the control unit increases the supply amount of the fuel gas from the fuel gas supply unit to the fuel cell.

[0021] In the present disclosure, the fuel gas and the oxidant gas are collectively referred to as reaction gases. The reaction gas supplied to the anode is the fuel gas, and the reaction gas supplied to the cathode is the oxidant gas. The fuel gas is a gas mainly containing hydrogen, and may also be hydrogen. The oxidant gas may also be oxygen, air, dry air, etc.

[0022] The fuel cell system of the present disclosure is used by being mounted on an aircraft.

[0023] In addition, the fuel cell system of the present disclosure may also be used by being mounted on an aircraft that can fly even with the power of a secondary battery.

[0024] The aircraft of the present disclosure may be an aircraft. The aircraft may be an airplane, a vertical takeoff and landing aircraft, etc. The vertical takeoff and landing aircraft may be a helicopter, a drone, etc.

[0025] The aircraft may also be equipped with the fuel cell system of the present disclosure.

[0026] The fuel cell system of the present disclosure includes a fuel cell.

[0027] The fuel cell may have only one single cell, or may be a fuel cell stack that is a laminate formed by laminating a plurality of single cells.

[0028] The number of stacked single cells is not particularly limited. For example, it may be 2 to several hundred, or may be 2 to 600.

[0029] The fuel cell stack may also have end plates at both ends in the stacking direction of the single cells.

[0030] The single cell of the fuel cell at least includes a membrane electrode gas diffusion layer assembly.

[0031] The membrane electrode gas diffusion layer assembly sequentially includes an anode-side gas diffusion layer, an anode catalyst layer, an electrolyte membrane, a cathode catalyst layer, and a cathode-side gas diffusion layer.

[0032] The cathode (oxidant electrode) includes a cathode catalyst layer and a cathode-side gas diffusion layer.

[0033] The anode (fuel electrode) includes an anode catalyst layer and a gas diffusion layer on the anode side.

[0034] The cathode catalyst layer and the anode catalyst layer are collectively referred to as the catalyst layer. In addition, as the anode catalyst and the cathode catalyst, for example, Pt (platinum), Ru (ruthenium), etc. can be cited. As the base material and conductive material for supporting the catalyst, for example, carbon materials such as carbon can be cited.

[0035] The gas diffusion layer on the cathode side and the gas diffusion layer on the anode side are collectively referred to as the gas diffusion layer.

[0036] The gas diffusion layer can also be a conductive component with air permeability, etc.

[0037] As the conductive component, for example, carbon porous bodies such as carbon cloth and carbon paper, and metal porous bodies such as metal mesh and foamed metal can be cited.

[0038] The electrolyte membrane can also be a solid polymer electrolyte membrane. As the solid polymer electrolyte membrane, for example, fluorine-based electrolyte membranes such as thin films containing perfluorosulfonic acid with moisture, and hydrocarbon-based electrolyte membranes can be cited. As the electrolyte membrane, for example, a perfluorosulfonic acid membrane (manufactured by DuPont) can also be used.

[0039] As needed, the single cell can also include two separators that sandwich both sides of the membrane electrode gas diffusion layer assembly. One of the two separators is the anode-side separator, and the other is the cathode-side separator. In the present disclosure, the anode-side separator and the cathode-side separator are collectively referred to as the separator.

[0040] The separator can also have supply holes and discharge holes for allowing reaction gases and refrigerant to flow in the stacking direction of the single cell. As the refrigerant, in order to prevent freezing at low temperatures, for example, a mixed solution of ethylene glycol and water can be used.

[0041] Examples of the supply holes include a fuel gas supply hole, an oxidant gas supply hole, and a refrigerant supply hole, etc.

[0042] Examples of the discharge holes include a fuel gas discharge hole, an oxidant gas discharge hole, and a refrigerant discharge hole, etc.

[0043] The separator can have one or more fuel gas supply holes, can have one or more oxidant gas supply holes, can have one or more refrigerant supply holes, can have one or more fuel gas discharge holes, can have one or more oxidant gas discharge holes, and can also have one or more refrigerant discharge holes.

[0044] The separator can also have a reaction gas flow path on the surface in contact with the gas diffusion layer. In addition, the separator can also have a refrigerant flow path for keeping the temperature of the fuel cell constant on the surface opposite to the surface in contact with the gas diffusion layer.

[0045] In the case where the separator is an anode-side separator, it may have more than one fuel gas supply hole, more than one oxidant gas supply hole, more than one refrigerant supply hole, more than one fuel gas discharge hole, more than one oxidant gas discharge hole, or more than one refrigerant discharge hole. The anode-side separator may have a fuel gas flow path on the surface in contact with the anode-side gas diffusion layer for the fuel gas to flow from the fuel gas supply hole to the fuel gas discharge hole, or may have a refrigerant flow path on the surface opposite to the surface in contact with the anode-side gas diffusion layer for the refrigerant to flow from the refrigerant supply hole to the refrigerant discharge hole.

[0046] In the case where the separator is a cathode-side separator, it may have more than one fuel gas supply hole, more than one oxidant gas supply hole, more than one refrigerant supply hole, more than one fuel gas discharge hole, more than one oxidant gas discharge hole, or more than one refrigerant discharge hole. The cathode-side separator may have an oxidant gas flow path on the surface in contact with the cathode-side gas diffusion layer for the oxidant gas to flow from the oxidant gas supply hole to the oxidant gas discharge hole, or may have a refrigerant flow path on the surface opposite to the surface in contact with the cathode-side gas diffusion layer for the refrigerant to flow from the refrigerant supply hole to the refrigerant discharge hole.

[0047] The separator may also be an airtight conductive component or the like. As the conductive component, for example, it may also be a dense carbon obtained by compressing carbon to be airtight, and a metal plate (such as iron, aluminum, and stainless steel, etc.) formed by stamping. In addition, the separator may also have a current collecting function.

[0048] The fuel cell may also have manifolds such as an inlet manifold communicating with each supply hole and an outlet manifold communicating with each discharge hole.

[0049] Examples of the inlet manifold include an anode inlet manifold, a cathode inlet manifold, and a refrigerant inlet manifold.

[0050] Examples of the outlet manifold include an anode outlet manifold, a cathode outlet manifold, and a refrigerant outlet manifold.

[0051] The fuel cell system includes a potential sensor.

[0052] The potential sensor measures the potential of the fuel cell. The potential may be the cathode potential or the anode potential.

[0053] The potential sensor is electrically connected to the control unit, and the control unit detects the potential of the fuel cell measured by the potential sensor.

[0054] The potential sensor can use a potentiometer or the like that has been publicly known in the past.

[0055] The fuel cell system includes a fuel gas system.

[0056] The fuel gas system supplies fuel gas to the fuel cell.

[0057] The fuel gas system has a fuel gas supply section.

[0058] The fuel gas system may also include a fuel gas supply flow path, an ejector, a circulation flow path, a gas-liquid separator, a fuel exhaust gas discharge flow path, and an exhaust drain valve.

[0059] The fuel gas supply section supplies fuel gas to the anode of the fuel cell.

[0060] As the fuel gas supply section, for example, a fuel tank or the like can be cited. Specifically, a liquid hydrogen tank, a compressed hydrogen tank, etc. can be cited.

[0061] The fuel gas supply section is electrically connected to the control section. The fuel gas supply section may be configured to control the opening and closing of the main shut-off valve of the fuel gas supply section according to a control signal from the control section, thereby controlling the on / off of the supply of fuel gas to the fuel cell.

[0062] The fuel gas supply flow path connects the fuel gas supply section to the fuel gas inlet of the fuel cell. The fuel gas supply flow path enables the supply of fuel gas to the anode of the fuel cell. The fuel gas inlet may also be a fuel gas supply hole, an anode inlet manifold, etc.

[0063] An ejector may be arranged in the fuel gas supply flow path.

[0064] The ejector may be arranged, for example, at the confluence section of the fuel gas supply flow path and the circulation flow path. The ejector supplies a mixed gas including fuel gas and circulation gas to the anode of the fuel cell. As the ejector, a publicly known ejector in the past can be adopted.

[0065] A pressure regulating valve and a medium-pressure hydrogen sensor may be arranged in the region between the fuel gas supply section and the ejector of the fuel gas supply flow path.

[0066] The pressure regulating valve regulates the pressure of the fuel gas supplied from the fuel gas supply section to the ejector.

[0067] It may be configured such that the pressure regulating valve is electrically connected to the control section, and the opening and closing and the opening degree, etc. of the pressure regulating valve are controlled by the control section, thereby adjusting the pressure of the fuel gas supplied to the ejector.

[0068] It can also be configured such that the medium-pressure hydrogen sensor is electrically connected to the control unit. The control unit detects the pressure of the fuel gas measured by the medium-pressure hydrogen sensor and controls the opening and closing and the opening degree of the pressure regulating valve based on the detected pressure, thereby adjusting the pressure of the fuel gas supplied to the ejector.

[0069] The fuel exhaust gas discharge flow path connects the fuel gas outlet of the fuel cell to the outside of the fuel cell system.

[0070] A gas-liquid separator may also be disposed in the region between the fuel gas outlet of the fuel exhaust gas discharge flow path and the outside of the fuel cell system.

[0071] The fuel exhaust gas discharge flow path may also branch from the circulation flow path via the gas-liquid separator.

[0072] The fuel exhaust gas discharge flow path discharges the fuel exhaust gas discharged from the fuel gas outlet of the fuel cell to the outside of the fuel cell system. The fuel gas outlet may also be a fuel gas discharge hole, an anode outlet manifold, etc.

[0073] An exhaust and drainage valve (fuel exhaust gas discharge valve) may also be disposed in the fuel exhaust gas discharge flow path. The exhaust and drainage valve is disposed at a position downstream of the gas-liquid separator in the fuel exhaust gas discharge flow path.

[0074] The exhaust and drainage valve can discharge the fuel exhaust gas, moisture, etc. to the outside (outside the system).

[0075] In addition, the outside may be the outside of the fuel cell system or the outside of the aircraft.

[0076] It can also be configured such that the exhaust and drainage valve is electrically connected to the control unit, and the control unit controls the opening and closing of the exhaust and drainage valve, thereby adjusting the discharge flow rate of the fuel exhaust gas to the outside and the drainage flow rate of the moisture (liquid water). Additionally, the pressure of the fuel gas supplied to the anode of the fuel cell (anode pressure) can also be adjusted by adjusting the opening degree of the exhaust and drainage valve.

[0077] The fuel exhaust gas may also include the fuel gas that directly passes through without reacting at the anode and the moisture such as the generated water generated at the cathode reaching the anode. There are cases where the fuel exhaust gas contains corrosion substances generated in the catalyst layer, electrolyte membrane, etc., and oxidant gases that may be supplied to the anode during scavenging.

[0078] The circulation flow path may also connect the fuel gas outlet of the fuel cell to the ejector.

[0079] It can also be configured such that the circulation flow path branches from the fuel exhaust gas discharge flow path and merges with the fuel gas supply flow path by connecting to the ejector disposed in the fuel gas supply flow path.

[0080] It can also be configured such that the circulation flow path branches from the fuel exhaust gas flow path via the gas-liquid separator and merges with the fuel gas supply flow path by connecting to the ejector disposed in the fuel gas supply flow path.

[0081] The circulation flow path can recover the fuel exhaust gas, which is the fuel gas discharged from the fuel gas outlet of the fuel cell, and supply it as the circulation gas to the fuel cell.

[0082] A gas circulation pump can also be disposed in the circulation flow path. The gas circulation pump circulates the fuel exhaust gas as the circulation gas. It can also be configured such that the gas circulation pump is electrically connected to the control unit, and the control unit controls the on / off and rotation speed, etc. of the drive of the gas circulation pump, thereby adjusting the flow rate of the circulation gas.

[0083] A gas-liquid separator (anode gas-liquid separator) can also be disposed in the circulation flow path.

[0084] The gas-liquid separator can also be disposed at the branch point of the fuel exhaust gas flow path and the circulation flow path.

[0085] Therefore, the flow path from the fuel gas outlet to the gas-liquid separator can be the fuel exhaust gas flow path or the circulation flow path.

[0086] The gas-liquid separator is disposed at a position upstream of the exhaust drain valve in the fuel exhaust gas flow path.

[0087] The gas-liquid separator separates the fuel exhaust gas, which is the fuel gas discharged from the fuel gas outlet, from the moisture (liquid water). Thereby, the fuel exhaust gas can be returned as the circulation gas to the circulation flow path, or the exhaust drain valve of the fuel exhaust gas flow path can be opened to discharge unnecessary gas and moisture, etc. to the outside. In addition, through the gas-liquid separator, the flow of excess moisture in the circulation flow path can be suppressed, and thus the generation of freezing of the circulation pump, etc. caused by this moisture can be suppressed.

[0088] The fuel cell system can also include an oxidant gas system.

[0089] The oxidant gas system can also include an oxidant gas supply unit, an oxidant gas supply flow path, an oxidant exhaust gas flow path, an oxidant gas bypass flow path, a bypass valve, and an oxidant gas flow sensor, etc.

[0090] The oxidant gas supply unit supplies the oxidant gas to the fuel cell. Specifically, the oxidant gas supply unit supplies the oxidant gas to the cathode of the fuel cell.

[0091] As the oxidant gas supply unit, for example, an air compressor, etc. can be used.

[0092] The oxidant gas supply unit is electrically connected to the control unit. The oxidant gas supply unit is driven according to a control signal from the control unit. The oxidant gas supply unit can also be controlled by the control unit to select at least one from the group consisting of the flow rate and pressure of the oxidant gas supplied from the oxidant gas supply unit to the cathode.

[0093] The oxidant gas supply flow path connects the oxidant gas supply unit to the oxidant gas inlet of the fuel cell. The oxidant gas supply flow path enables the supply of the oxidant gas from the oxidant gas supply unit to the cathode of the fuel cell. The oxidant gas inlet can also be an oxidant gas supply hole, a cathode inlet manifold, etc.

[0094] The oxidant exhaust gas discharge flow path is connected to the oxidant gas outlet of the fuel cell. The oxidant exhaust gas discharge flow path enables the discharge of the oxidant exhaust gas, which is the oxidant gas discharged from the cathode of the fuel cell, to the outside. The oxidant gas outlet can also be an oxidant gas discharge hole, a cathode outlet manifold, etc.

[0095] An oxidant gas pressure regulating valve can also be provided in the oxidant exhaust gas discharge flow path.

[0096] The oxidant gas pressure regulating valve is electrically connected to the control unit. By opening the oxidant gas pressure regulating valve through the control unit, the oxidant exhaust gas, which is the reacted oxidant gas, is discharged from the oxidant exhaust gas discharge flow path to the outside. In addition, the pressure of the oxidant gas supplied to the cathode (cathode pressure) can also be adjusted by adjusting the opening degree of the oxidant gas pressure regulating valve.

[0097] The oxidant gas bypass flow path branches from the oxidant gas supply flow path, bypasses the fuel cell, and connects the branch portion of the oxidant gas supply flow path to the confluence portion of the oxidant exhaust gas discharge flow path.

[0098] A bypass valve is arranged in the oxidant gas bypass flow path.

[0099] The bypass valve is electrically connected to the control unit. By opening the bypass valve through the control unit, when the supply of the oxidant gas to the fuel cell is not required, the oxidant gas can be discharged to the outside from the oxidant exhaust gas discharge flow path bypassing the fuel cell.

[0100] The oxidant gas flow sensor is arranged in the oxidant gas supply flow path.

[0101] The oxidant gas flow sensor detects the flow rate of the oxidant gas in the oxidant gas system. The oxidant gas flow sensor is electrically connected to the control unit. The control unit can also infer the rotational speed of the air compressor based on the flow rate of the oxidant gas detected by the oxidant gas flow sensor. The oxidant gas flow sensor can also be arranged at a position upstream of the oxidant gas supply unit in the oxidant gas supply flow path.

[0102] The oxidant gas flow sensor can adopt a conventionally known flowmeter or the like.

[0103] The fuel cell system may also include a cooling system for the fuel cell.

[0104] The cooling system may include a refrigerant supply section and may also include a refrigerant circulation flow path.

[0105] The refrigerant circulation flow path is connected to the refrigerant supply hole and the refrigerant discharge hole provided in the fuel cell, and can circulate the refrigerant supplied from the refrigerant supply section inside and outside the fuel cell.

[0106] The refrigerant supply section is electrically connected to the control section. The refrigerant supply section is driven according to a control signal from the control section. The refrigerant supply section is controlled by the control section to control the flow rate of the refrigerant supplied from the refrigerant supply section to the fuel cell. Thus, the temperature of the fuel cell can also be controlled.

[0107] Examples of the refrigerant supply section include a cooling water pump or the like.

[0108] A radiator for dissipating the heat of the cooling water may also be provided in the refrigerant circulation flow path.

[0109] A storage tank for storing the refrigerant may also be provided in the refrigerant circulation flow path.

[0110] The fuel cell system may also include a secondary battery.

[0111] The secondary battery (battery) only needs to be able to charge and discharge. For example, conventionally known secondary batteries such as nickel-metal hydride secondary batteries and lithium-ion secondary batteries can be cited. In addition, the secondary battery may also include energy storage elements such as electric double layer capacitors. The secondary battery may also be a structure in which a plurality are connected in series. The secondary battery supplies power to an electric motor, an air compressor, etc. The secondary battery can also be charged, for example, from a power source outside the aircraft. The secondary battery can also be charged by the output of the fuel cell. The charging and discharging of the secondary battery can also be controlled by the control section.

[0112] Physically, the control section has, for example, an arithmetic processing device such as a CPU (Central Processing Unit), a ROM (Read Only Memory) for storing a control program and control data processed by the CPU, a storage device such as a RAM (Random Access Memory) mainly used as various working areas for control processing, and an input / output interface. In addition, the control section may also be a control device such as an electronic control unit (ECU: Electronic Control Unit).

[0113] The control unit may also be electrically connected to the ignition switch, which may also be mounted on a vehicle. It may also be configured such that even when the ignition switch is turned off, the control unit can operate via an external power source.

[0114] The control unit determines whether the potential of the fuel cell measured by the potential sensor is a reverse potential.

[0115] When it is determined that the potential of the fuel cell is a reverse potential, the control unit increases the supply amount of the fuel gas from the fuel gas supply unit to the fuel cell.

[0116] The increased supply amount of the fuel gas is not particularly limited as long as it is greater than the supply amount at the time of determination or the supply amount at the current time, and may be appropriately set to an amount that makes the potential of the fuel cell become a positive potential.

[0117] In the present disclosure, even when the potential of the fuel cell becomes a reverse potential, the output of the fuel cell is not immediately limited, but control is performed to increase the supply amount of the fuel gas in the fuel gas system. If the potential of the fuel cell does not return to a positive potential even through this control, the output of the fuel cell is limited, or the fuel cell system is stopped.

[0118] It may also be configured such that the control unit monitors the potential of the fuel cell and records the cumulative time of the state in which the potential of the fuel cell is a reverse potential.

[0119] It may also be configured such that when it is determined that the potential of the fuel cell is a reverse potential, the control unit determines whether the cumulative time is less than a specified time.

[0120] It may also be configured such that when it is determined that the cumulative time is less than the specified time, the control unit increases the supply amount of the fuel gas from the fuel gas supply unit to the fuel cell.

[0121] For the specified time of the cumulative time, for example, it may be appropriately set to a time when it is considered that the possibility of the potential of the fuel cell returning from the reverse potential to a positive potential is low when this time has elapsed. Thus, by pre-recording the cumulative time, it is possible to determine whether the state of the reverse potential is a state that can be expected to return to a positive potential in the case where the potential of the fuel cell becomes a reverse potential, then returns to a positive potential state, and then becomes a reverse potential state again, etc.

[0122] In the present disclosure, the potential of the fuel cell is monitored, the cumulative time of the reverse potential state is recorded, and when the cumulative time is longer than the specified time, if the potential of the fuel cell becomes a reverse potential, control to increase the supply amount of the fuel gas is not performed, but control to limit the output of the fuel cell is immediately performed.

[0123] Figure 1This is a schematic structural diagram showing an example of the fuel cell system of the present disclosure.

[0124] Figure 1 The illustrated fuel cell system 100 includes a fuel cell 10, a fuel gas supply unit 20, a fuel gas supply flow path 21, a fuel exhaust gas discharge flow path 22, an exhaust drain valve 23, a gas-liquid separator 24, a circulation flow path 25, an ejector 26, a control unit 50, and a potential sensor 60.

[0125] In addition, in Figure 1 only the fuel gas system is illustrated, and the illustration of other oxidant gas systems, cooling systems, etc. is omitted.

[0126] Figure 2 This is a flowchart showing an example of the control of the fuel cell system of the present disclosure.

[0127] First, the control unit monitors the potential measured by the potential sensor.

[0128] Moreover, the control unit determines whether the potential measured by the potential sensor is a reverse potential.

[0129] When it is determined that the potential measured by the potential sensor is a reverse potential, the control unit increases the supply amount of the fuel gas from the fuel gas supply unit to the fuel cell compared to the current moment and ends the control. It can also be configured that: thereafter, when it is detected that the potential measured by the potential sensor has changed from the reverse potential to a positive potential, the control unit records the time from the state of the reverse potential of the fuel cell to the change to the positive potential.

[0130] On the other hand, when it is determined that the potential measured by the potential sensor is not a reverse potential, the control unit can end the control or maintain the supply amount of the fuel gas at the current moment from the fuel gas supply unit to the fuel cell and continue to monitor.

[0131] Figure 3 This is a flowchart showing another example of the control of the fuel cell system of the present disclosure.

[0132] First, the control unit monitors the potential measured by the potential sensor. The control unit can also record the cumulative time of the state in which the potential of the fuel cell is a reverse potential.

[0133] Moreover, the control unit determines whether the potential measured by the potential sensor is a reverse potential.

[0134] When it is determined that the potential measured by the potential sensor is not a reverse potential, the control unit can end the control or maintain the supply amount of the fuel gas at the current moment from the fuel gas supply unit to the fuel cell and continue to monitor.

[0135] On the other hand, when it is determined that the potential of the fuel cell is the reversal potential, the control unit determines whether the cumulative time in the state where the potential of the fuel cell is the reversal potential is less than a specified time.

[0136] When it is determined that the cumulative time is equal to or more than the specified time, the control unit limits the output of the fuel cell, or stops the fuel cell system and ends the control.

[0137] On the other hand, when it is determined that the cumulative time is less than the specified time, the control unit increases the supply amount of the fuel gas from the fuel gas supply unit to the fuel cell. The control unit also records the time in the state where the potential of the fuel cell is the reversal potential. Moreover, the control unit determines whether the cumulative time is equal to or more than the specified time. When it is determined that the cumulative time is less than the specified time, the control unit continues to record the time in the state where the potential of the fuel cell is the reversal potential. On the other hand, when it is determined that the cumulative time is equal to or more than the specified time, the control unit limits the output of the fuel cell, or stops the fuel cell system and ends the control.

Claims

1. A fuel cell system, which is a fuel cell system for an aircraft, is characterized in that the fuel cell system has: a fuel cell; a fuel gas system for supplying fuel gas to the fuel cell; a potential sensor; and a control unit, the fuel gas system has a fuel gas supply unit, the control unit determines whether the potential of the fuel cell measured by the potential sensor is a reverse potential, the control unit monitors the potential of the fuel cell and records the cumulative time of the state in which the potential of the fuel cell is a reverse potential, when it is determined that the potential of the fuel cell is a reverse potential, the control unit determines whether the cumulative time is less than a specified time, when it is determined that the cumulative time is less than the specified time, the control unit increases the supply amount of the fuel gas from the fuel gas supply unit to the fuel cell.

2. An aircraft, wherein it is equipped with the fuel cell system according to claim 1.

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