FUEL CELL SYSTEM

Abstract

Fuel cell system (100, 200, 300), wherein the fuel cell system (100, 200, 300) comprises: a fuel cell (10), a fuel gas supplier (20) for supplying hydrogen-containing fuel gas to the fuel cell (10), a fuel gas supply flow path (21) connecting a fuel gas inlet of the fuel cell (10) and the fuel gas supplier (20), a pressure sensor (60) which is arranged in the fuel gas supply flow path (21), an exhaust gas discharge flow path (22) for discharging the exhaust gas discharged from a fuel gas outlet of the fuel cell (10) to the outside of the fuel cell system (100, 200, 300), a venting and discharge valve (23) arranged in the exhaust gas discharge flow path (22), and a controller (50), wherein the controller (50) stores in advance a data set which specifies a relationship between a quantity of the supplied hydrogen gas and a hydrogen pressure increase rate when a predetermined quantity of hydrogen gas is supplied by the fuel gas supplier (20); wherein the controller (50) calculates a fuel gas pressure increase rate from a pressure change detected by the pressure sensor (60) when the fuel gas is supplied to the fuel cell (10); wherein the control (50) determines whether the fuel gas pressure increase rate is less than the hydrogen pressure increase rate or not; and wherein, if the controller (50) determines that the fuel gas pressure increase rate is less than the hydrogen pressure increase rate, the controller (50) prevents the fuel cell (10) from generating energy.

Description

TECHNICAL AREA

[0001] The invention relates to a fuel cell system. BACKGROUND

[0002] A fuel cell (FC) is a device for generating energy that produces electrical energy through an electrochemical reaction between fuel gas (e.g., hydrogen) and oxidant gas (e.g., oxygen) in a single fuel cell unit or a fuel cell stack (hereinafter referred to as a "stack") consisting of stacked fuel cell units (hereinafter referred to as a "cell"). In many cases, the fuel gas and oxidant gas supplied to the fuel cell are mixtures with gases that do not contribute to oxidation and reduction. In particular, the oxidant gas is often oxygen-containing air.

[0003] In the following, fuel gas and oxidant gas will be referred to collectively and simply as "reaction gas" or "gas". A single fuel cell unit and a fuel cell stack consisting of stacked cells can also be referred to as a "fuel cell".

[0004] In general, the fuel cell unit includes a membrane electrode assembly (MEA).

[0005] The membrane electrode assembly is structured such that a catalyst layer and a gas diffusion layer (or GDL, hereinafter referred to simply as the "diffusion layer") are sequentially formed on both surfaces of a solid polymer electrolyte membrane (hereinafter referred to simply as the "electrolyte membrane"). Accordingly, the assembly of the membrane electrode can be described as a "membrane electrode gas diffusion layer assembly" (MEGA).

[0006] Depending on requirements, the fuel cell unit includes two separators that enclose both sides of the membrane electrode-gas diffusion layer assembly. Generally, the separators are structured such that a groove is formed on the surface in contact with the gas diffusion layer, serving as a flow path for the reaction gas. The separators are electrically conductive and act as collectors for the generated electricity.

[0007] In the fuel electrode (anode) of the fuel cell, hydrogen (H₂) is supplied as fuel gas from the gas flow path and the gas diffusion layer. This hydrogen is protonated by the catalytic action of the catalyst layer, and the protonated hydrogen passes through the electrolyte membrane to the oxidation electrode (cathode). Simultaneously, an electron is generated, which traverses an external circuit, performs work, and then travels to the cathode. The oxygen (O₂) supplied to the cathode as the oxidizing gas reacts with protons and electrons in the cathode's catalytic layer, producing water. The water releases a suitable amount of moisture to the electrolyte membrane, and excess water enters the gas diffusion layer and is then released to the outside of the system.

[0008] Several studies have been conducted on fuel cell systems configured to be installed and used in fuel cell electric vehicles (hereinafter referred to as "vehicle").

[0009] For example, patent literature 1 discloses a fuel cell system configured to reduce start-up time.

[0010] Patent literature 2 discloses a fuel cell system configured to suppress the useless operation of a compressor, etc., and the useless consumption of hydrogen when starting the system.

[0011] Furthermore, patent literature 3 and patent literature 4 disclose fuel cell systems from the prior art. Patent literature 1: JP 2007 - 165 103 A Patent literature 2: JP 2004 - 296 351 A Patent literature 3: JP 2006 - 309 948 A Patent literature 4: WO 2016 / 067 788 A1

[0012] Efficient energy generation from a fuel cell cannot be achieved if impurity gas is present in the hydrogen-containing fuel gas; furthermore, irreversible performance degradation is caused by catalyst degradation. Therefore, it is important to control the purity of the fuel gas in the fuel cell.

[0013] If hydrogen refueling stations become more popular in the future and their number increases, there is a possibility that some stations will supply fuel gas with low hydrogen purity. Furthermore, there is a possibility that low-quality gas containing large amounts of other gases will be filled into the fuel tanks of fuel cell electric vehicles. If low-quality gas is filled into the fuel tanks of fuel cell electric vehicles, it is essential to detect the gas before the fuel cell generates energy and prevent irreversible performance degradation.

[0014] According to the current state of the art, the fuel cell's control system is modified at the time of energy generation, for example, by estimating the partial pressure of a different foreign gas than hydrogen in the fuel cell. Even with the current state of the art, the state of the hydrogen in the fuel gas in the fuel gas tank is not detected in advance, and there is a possibility that an irreversible reduction in the fuel cell's performance could be caused by the introduction of low-quality gas. Furthermore, even with the current state of the art, abnormal hydrogen purity in the fuel gas in the fuel gas tank cannot be detected before energy generation. SUMMARY

[0015] The disclosed embodiments were achieved in light of the circumstances described above. One objective of the disclosed embodiments is to provide a fuel cell system configured to suppress the irreversible power degradation of a fuel cell.

[0016] The fuel cell system of the disclosed embodiments is a fuel cell system, the fuel cell system features: a fuel cell a fuel gas supplier for supplying hydrogen-containing fuel gas to the fuel cell, a fuel gas supply flow path that connects a fuel gas inlet of the fuel cell and the fuel gas supplier, a pressure sensor located in the fuel gas supply flow path, an exhaust gas discharge flow path for discharging the exhaust gas discharged from a fuel gas outlet of the fuel cell to the outside of the fuel cell system, a venting and discharge valve arranged in the exhaust gas discharge flow path, and a control system wherein the control system stores in advance a data set that specifies a relationship between a quantity of supplied hydrogen gas and a hydrogen pressure increase rate when a predetermined quantity of hydrogen gas is supplied by the fuel gas supplier; the control system calculates a fuel gas pressure increase rate from a pressure change detected by the pressure sensor when the fuel gas is supplied to the fuel cell; the control system determines whether the fuel gas pressure increase rate is lower than the hydrogen pressure increase rate or not; and However, if the control system determines that the fuel gas pressure increase rate is lower than the hydrogen pressure increase rate, the control system prevents the fuel cell from generating energy.

[0017] In the fuel cell system of the disclosed embodiments, the controller can pre-store a data set indicating a hydrogen pressure after a predetermined period, provided the predetermined quantity of hydrogen gas is supplied by the fuel gas supplier; if the controller determines that the fuel gas pressure increase rate is lower than the hydrogen pressure increase rate, the controller can determine whether the fuel gas pressure is lower than the hydrogen pressure after the predetermined period; and if the controller determines that the fuel gas pressure is lower than the hydrogen pressure after the predetermined period, the controller can prevent the fuel cell from generating energy.

[0018] The fuel cell system of the disclosed embodiments is a fuel cell system, the fuel cell system features: a fuel cell a fuel gas supplier for supplying hydrogen-containing fuel gas to the fuel cell, a fuel gas supply flow path that connects a fuel gas inlet of the fuel cell and the fuel gas supplier, a pressure sensor located in the fuel gas supply flow path, an exhaust gas discharge flow path for discharging the exhaust gas discharged from a fuel gas outlet of the fuel cell to the outside of the fuel cell system, a venting and discharge valve arranged in the exhaust gas discharge flow path, and a control system wherein the control system stores a data set in advance that indicates a hydrogen pressure after a predetermined period of time, when a predetermined quantity of hydrogen gas is supplied from the fuel gas supplier; wherein the control system determines whether the fuel gas pressure is lower than the hydrogen pressure after the predetermined period; and where, if the control system determines that the fuel gas pressure is lower than the hydrogen pressure after the predetermined period, the control system prevents the fuel cell from generating energy.

[0019] In the fuel cell system of the disclosed embodiments, the controller can pre-store a data set that specifies a relationship between a quantity of supplied hydrogen gas and a hydrogen pressure increase rate when the predetermined quantity of hydrogen gas is supplied by the fuel gas supplier; if the controller determines that the fuel gas pressure is less than a predetermined threshold after the predetermined period has elapsed, the controller can calculate a fuel gas pressure increase rate from a pressure change detected by the pressure sensor when the fuel gas is supplied to the fuel cell; the controller can determine whether the fuel gas pressure increase rate is less than the hydrogen pressure increase rate; and if the controller determines that the fuel gas pressure increase rate is less than the hydrogen pressure increase rate, the controller can prevent the fuel cell from generating energy.

[0020] The fuel cell system of the disclosed embodiments suppresses the irreversible power degradation of the fuel cell. BRIEF DESCRIPTION OF THE DRAWING

[0021] In the attached drawing: Fig. Figure 1 is a view showing an example of the relationship between the hydrogen concentration, the molecular weight of the hydrogen gas, and the multiple of time required to fill pressurized fuel gas into the fuel cell when the fuel cell system is activated; Fig. Figure 2 is a view showing an example of the relationship between the pressure of normal fuel gas containing no impurity gas and the injection time or spray time of the normal fuel gas into the fuel cell, and an example of the relationship between the pressure of abnormal fuel gas containing impurity gas and the injection time of the abnormal fuel gas into the fuel cell; Fig. Figure 3 is a schematic configuration diagram of an example of the fuel cell system of the disclosed embodiments; Fig. Figure 4 is a schematic configuration diagram of another example of the fuel cell system of the disclosed embodiments; Fig. Figure 5 is a schematic configuration diagram of another example of the fuel cell system of the disclosed embodiments; Fig. 6 is a flowchart illustrating an example of the control of the fuel cell system of the disclosed embodiments; Fig. 7 is a flowchart illustrating another example of the control of the fuel cell system of the disclosed embodiments; Fig. 8 is a flowchart illustrating another example of the control of the fuel cell system of the disclosed embodiments; Fig. 9 is a flowchart illustrating another example of the control of the fuel cell system of the disclosed embodiments; Fig. 10 is a flowchart illustrating a further example of the control of the fuel cell system of the disclosed embodiments; and Fig. Figure 11 is a flowchart illustrating another example of the control of the fuel cell system of the disclosed embodiments. DETAILED DESCRIPTION

[0022] The fuel cell system of the disclosed embodiments is a fuel cell system, the fuel cell system features: a fuel cell a fuel gas supplier for supplying hydrogen-containing fuel gas to the fuel cell, a fuel gas supply flow path that connects a fuel gas inlet of the fuel cell and the fuel gas supplier, a pressure sensor located in the fuel gas supply flow path, an exhaust gas discharge flow path for discharging the exhaust gas discharged from a fuel gas outlet of the fuel cell to the outside of the fuel cell system, a venting and discharge valve arranged in the exhaust gas discharge flow path, and a control system wherein the control system stores in advance a data set that specifies a relationship between a quantity of supplied hydrogen gas and a hydrogen pressure increase rate when a predetermined quantity of hydrogen gas is supplied by the fuel gas supplier; the control system calculates a fuel gas pressure increase rate from a pressure change detected by the pressure sensor when the fuel gas is supplied to the fuel cell; the control system determines whether the fuel gas pressure increase rate is lower than the hydrogen pressure increase rate or not; and However, if the control system determines that the fuel gas pressure increase rate is lower than the hydrogen pressure increase rate, the control system prevents the fuel cell from generating energy.

[0023] Fig. Figure 1 is a view showing an example of the relationship between the hydrogen concentration, the molecular weight of the hydrogen gas, and the multiple of time required to fill the fuel cell with pressurized fuel when the fuel cell system is activated.

[0024] As in Fig. As shown in Figure 1, it was found that if an impurity gas other than hydrogen is present in the fuel gas, the density of the fuel gas increases, thereby reducing the flow velocity of the fuel gas injected from the fuel gas supplier and decreasing the gas pressure rise rate, since hydrogen has the lowest molecular weight among gases and a low density. At the time the fuel gas is introduced from the fuel gas supplier into the fuel cell, the flow velocity of the injected fuel gas varies depending on the presence or absence of an impurity in the fuel gas. Accordingly, the presence or absence of an impurity can be determined by a difference in the pressure rise rate from the start of the fuel gas supply to the fuel cell.

[0025] According to one embodiment of the fuel cell system, even low-quality gas containing large amounts of impurities can be detected before the fuel cell generates energy.

[0026] Using the phenomenon that the gas pressure increase rate varies depending on the type of gas when the fuel gas is supplied to the fuel cell by the fuel gas supplier at the time of activation of the fuel cell system, the fuel gas system of the disclosed embodiments detects foreign gas, estimates the amount of impurity and prevents the fuel cell from generating energy if the amount of impurity is estimated to be large.

[0027] The fuel cell system of the disclosed embodiments can suppress hydrogen deficiency in the fuel cell by detecting the impurity gas before the fuel cell generates energy and preventing the fuel cell from generating energy.

[0028] In the disclosed embodiments, the fuel gas and the oxidizing agent gas are collectively referred to as the "reaction gas." The reaction gas supplied to the anode is the fuel gas, and the reaction gas supplied to the cathode is the oxidizing agent gas. The fuel gas is a gas containing mainly hydrogen, and it can be hydrogen. The oxidizing agent gas can be oxygen, air, dry air, or the like.

[0029] In the illustrated embodiments, the impurity can be nitrogen, carbon monoxide, hydrogen sulfide or similar substances.

[0030] In general, the fuel cell system of the disclosed embodiments is installed and used in a vehicle that includes an engine as a power source.

[0031] The fuel cell system of the disclosed embodiments can be installed and used in a vehicle that can be powered by the energy of a secondary cell.

[0032] The motor is not particularly limited and can be a conventionally known drive motor.

[0033] The vehicle can be a fuel cell electric vehicle.

[0034] The vehicle can include the fuel cell system of the disclosed embodiments.

[0035] The fuel cell system of the disclosed embodiments includes the fuel cell.

[0036] The fuel cell can be a fuel cell consisting of a single fuel cell unit, or a fuel cell stack consisting of stacked fuel cell units.

[0037] The number of stacked fuel cell units is not particularly limited. For example, anywhere from 2 to several hundred fuel cell units can be stacked, or from 2 to 300 fuel cell units can be stacked.

[0038] The fuel cell stack can include an end plate at both ends of each fuel cell unit in the stacking direction.

[0039] Each fuel cell unit includes at least one assembly of membrane electrode gas diffusion layers.

[0040] The assembly of the membrane electrode gas diffusion layer includes an anode-side gas diffusion layer, an anode-side catalyst layer, an electrolyte membrane, a cathode-side catalyst layer, and a cathode-side gas diffusion layer in that order.

[0041] The cathode (oxidizing agent electrode) includes the catalyst layer of the cathode and the cathode-side gas diffusion layer.

[0042] The anode (fuel electrode) includes the anode-side catalyst layer and the anode-side gas diffusion layer.

[0043] The cathode catalyst layer and the anode catalyst layer are collectively referred to as the "catalyst layer." Examples of anode and cathode catalysts include platinum (Pt) and ruthenium (Ru), but are not limited to these. Examples of catalyst support and conductive materials include carbon-containing materials such as carbon, but are not limited to these.

[0044] The cathode-side gas diffusion layer and the anode-side gas diffusion layer are collectively referred to as the "gas diffusion layer".

[0045] The gas diffusion layer can be a gas-permeable, electrically conductive element or something similar.

[0046] Examples of an electrically conductive element include, but are not limited to, a porous carbon material such as carbon fabric and carbon paper, and a porous metallic material such as metal fabric and metal foam.

[0047] The electrolyte membrane can be a solid electrolyte membrane made of polymers. Examples of solid electrolyte membranes made of polymers include, but are not limited to, hydrocarbon electrolyte membranes and fluorine electrolyte membranes such as thin, moisture-containing perfluorosulfonic acid membranes. The electrolyte membrane could, for example, be a Nafion membrane (manufactured by DuPont Co., Ltd.).

[0048] Depending on requirements, each fuel cell unit can include two separators that enclose both sides of the membrane electrode gas diffusion layer assembly. One of the two separators is an anode-side separator, and the other is a cathode-side separator. In the disclosed embodiments, the anode-side separator and the cathode-side separator are collectively referred to as the "separator".

[0049] The separator can include inlet and outlet holes to allow the reaction gas and refrigerant to flow in the stacking direction of the fuel cell units. A mixed solution of ethylene glycol and water, for example, can be used as the refrigerant to prevent freezing at low temperatures.

[0050] The supply ports include, but are not limited to, a fuel gas supply port, an oxidizing gas supply port and a refrigerant supply port.

[0051] The outlet holes include, for example, a fuel gas outlet hole, an oxidizer gas outlet hole, and a coolant outlet hole, but are not limited to these.

[0052] The separator may include one or more fuel gas supply holes, one or more oxidizer gas supply holes, one or more refrigerant supply holes, one or more fuel gas outlet holes, one or more oxidizer gas outlet holes, and one or more refrigerant outlet holes.

[0053] The separator may include a reaction gas flow path on a surface in contact with the gas diffusion layer. The separator may also include a refrigerant flow path to maintain a constant fuel cell temperature on the surface opposite the surface in contact with the gas diffusion layer.

[0054] If the separator is an anode-side separator, it may include one or more fuel gas supply holes, one or more oxidizer gas supply holes, one or more refrigerant supply holes, one or more fuel gas outlet holes, one or more oxidizer gas outlet holes, and one or more refrigerant outlet holes. The anode-side separator may include a fuel gas flow path that allows the fuel gas to flow from the fuel gas supply hole to the fuel gas outlet hole on the surface in contact with the anode-side gas diffusion layer. The anode-side separator may include a refrigerant flow path that allows the refrigerant to flow from the refrigerant supply hole to the refrigerant outlet hole on the surface opposite the surface in contact with the anode-side gas diffusion layer.

[0055] If the separator is the cathode-side separator, it may include one or more fuel gas supply holes, one or more oxidizer gas supply holes, one or more refrigerant supply holes, one or more fuel gas outlet holes, one or more oxidizer gas outlet holes, and one or more refrigerant outlet holes. The cathode-side separator may include an oxidizer gas flow path to allow the oxidizer gas to flow from the oxidizer gas supply hole to the oxidizer gas outlet hole on the surface in contact with the cathode-side gas diffusion layer. The cathode-side separator may also include a refrigerant flow path to allow the refrigerant to flow from the refrigerant supply hole to the refrigerant outlet hole on the surface opposite the surface in contact with the cathode-side gas diffusion layer.

[0056] The separator can be a gas-impermeable, electrically conductive element, or something similar. Examples of electrically conductive elements include, but are not limited to, gas-impermeable, dense carbon obtained by carbon compaction, and a metal plate (such as an iron plate, an aluminum plate, or a stainless steel plate) obtained by pressing. The separator can also function as a collector.

[0057] The fuel cell stack can include a distributor, e.g. an inlet distributor that communicates between the feed holes, and an outlet distributor that communicates between the outlet holes.

[0058] Examples of inlet manifolds include, but are not limited to, an anode inlet manifold, a cathode inlet manifold, and a coolant inlet manifold.

[0059] The outlet distributors include, for example, an anode outlet distributor, a cathode outlet distributor and a refrigerant outlet distributor, but are not limited to these.

[0060] The fuel cell system includes, as the fuel gas system of the fuel cell, the fuel gas supplier, the fuel gas supply flow path, the pressure sensor, the exhaust gas discharge flow path, the venting and discharge valve, and the control system.

[0061] The fuel gas supplier delivers the hydrogen-containing fuel gas to the fuel cell. More precisely, the fuel gas supplier delivers the hydrogen-containing fuel gas to the anode of the fuel cell.

[0062] For example, a fuel tank such as a liquid hydrogen tank or a pressurized hydrogen tank is included as a fuel gas supplier, but is not limited to that.

[0063] The fuel gas supplier is electrically connected to the control unit. The fuel gas supplier controls the switching on and off of the fuel gas supply to the fuel cell by opening and closing the main shut-off valve of the fuel gas supplier according to a control signal from the control unit.

[0064] The fuel gas supply path connects the fuel cell's fuel gas inlet and the fuel gas supplier. Fuel gas can be supplied to the fuel cell's anode via this path. The fuel gas inlet can be the fuel gas feed port, the distributor for the anode inlet, or a similar component.

[0065] The pressure sensor is located in the fuel gas supply flow path.

[0066] The pressure sensor measures the pressure of the fuel gas supplied to the fuel cell. The pressure sensor is electrically connected to the controller, and the controller detects the fuel gas pressure measured by the pressure sensor.

[0067] A standard pressure gauge or similar device can be used as a pressure sensor.

[0068] The exhaust gas discharge path releases the exhaust gas emitted from the fuel cell's fuel gas outlet to the outside of the fuel cell system. The fuel gas outlet can be the fuel gas outlet hole, the distributor for the anode outlet, or similar.

[0069] The venting and discharge valve (the exhaust gas discharge valve) is located in the exhaust gas discharge flow path.

[0070] The venting and discharge valve allows exhaust gas, water, and similar substances to be released to the outside (of the system). The outside can be the outside of the fuel cell system or the outside of the vehicle.

[0071] The venting and discharge valve can be electrically connected to the control unit, and the flow rate of the exhaust gas discharged to the outside can be controlled by the control unit by controlling the opening and closing of the venting and discharge valve. By controlling the degree of opening of the venting and discharge valve, the pressure of the fuel gas supplied to the anode of the fuel cell (anode pressure) can be controlled.

[0072] The exhaust gas may contain the fuel gas that has passed through the anode without reaction, as well as the water that was generated at the cathode and transferred to the anode. In some cases, the exhaust gas contains corroded substances that were generated in the catalyst layer, the electrolyte membrane, etc., and the oxidizer gas, etc., that is supplied to the anode during purging.

[0073] The fuel cell system may include a circulation flow path.

[0074] The circulation flow path makes it possible to recover the exhaust gas, i.e., the fuel gas discharged from the fuel gas outlet of the fuel cell, and to supply it to the fuel cell as circulation gas.

[0075] The circulation flow path can branch off from the exhaust gas discharge flow path and connect to the fuel gas supply flow path.

[0076] The circulation flow path can branch off from the exhaust gas discharge flow path and connect to an ejector, which may be located in the fuel gas supply flow path.

[0077] The circulation flow path can branch off from the exhaust gas discharge flow path via the gas-liquid separator and be connected to the ejector located in the fuel gas supply flow path, thus creating the fuel gas supply flow path.

[0078] The ejector can, for example, be located at an intersection with the circulation flow path on the fuel gas supply flow path. The ejector supplies the fuel cell anode with a mixed gas containing the fuel gas and the circulation gas. A commercially available ejector can be used.

[0079] In the fuel cell system, a circulation pump (e.g. a hydrogen pump to control the flow rate of the circulating gas) or similar device can be arranged on the circulation flow path if required.

[0080] The circulation pump can be electrically connected to the controller, and the flow rate of the circulating gas can be controlled by the controller through the on / off control, rotation frequency, etc. of the circulation pump.

[0081] The fuel cell system may include an anode gas-liquid separator.

[0082] The anode gas-liquid separator can be located at the junction of the exhaust gas discharge path and the recirculation path. In this case, the exhaust gas discharge valve can be located downstream of the anode gas-liquid separator. The anode gas-liquid separator separates the water contained in the exhaust gas from the fuel gas, which is the fuel gas discharged from the fuel gas outlet. Accordingly, the fuel gas can be recirculated back into the recirculation path, or excess gas, water, and the like can be discharged to the outside by opening the exhaust gas discharge valve. The anode gas-liquid separator can also prevent excess water from flowing into the recirculation path. Accordingly, the freezing of the circulation pump or similar can be suppressed by the water.

[0083] As an oxidant gas system of the fuel cell, the fuel cell system can include an oxidant gas supplier, an oxidant gas supply flow path, and an oxidant exhaust gas discharge flow path.

[0084] The oxidizer gas supplier delivers the oxidizer gas to the fuel cell. More precisely, the oxidizer gas supplier delivers the oxidizer gas to the cathode of the fuel cell.

[0085] An air compressor, for example, can be used as the oxidizing gas supplier.

[0086] The oxidizer gas supplier is electrically connected to the control unit. The oxidizer gas supplier is controlled by the control unit via a control signal. At least one of the elements from the group consisting of the flow rate and pressure of the oxidizer gas supplied to the cathode by the oxidizer gas supplier can be controlled by the control unit.

[0087] The flow path for the oxidant gas supply connects the oxidant gas supplier and the oxidant gas inlet of the fuel cell. This flow path allows the oxidant gas to be delivered from the oxidant gas supplier to the cathode of the fuel cell. The oxidant gas inlet can be the oxidant gas supply port, the cathode inlet manifold, or a similar component.

[0088] The oxidizer exhaust gas discharge path is connected to the oxidizer gas outlet of the fuel cell. The oxidizer gas emitted from the fuel cell's cathode can be discharged to the outside via this path. The oxidizer gas outlet can be the oxidizer gas outlet port, the cathode outlet manifold, or a similar component.

[0089] The oxidizer exhaust gas discharge flow path can be provided with an oxidizer gas pressure regulating valve.

[0090] The oxidizer gas pressure control valve is electrically connected to the control unit. When the control unit opens the oxidizer gas pressure control valve, the oxidizer exhaust gas, i.e., the reacted oxidizer gas, is discharged to the outside of the oxidizer exhaust gas discharge path. The pressure of the oxidizer gas supplied to the cathode (cathode pressure) can be regulated by controlling the opening degree of the oxidizer gas pressure control valve.

[0091] The fuel cell system can include a refrigerant supplier and a refrigerant circulation flow path as the cooling system of the fuel cell.

[0092] The refrigerant circulation flow path communicates between the refrigerant supplier and the outlet holes provided in the fuel cell, enabling the circulation of the refrigerant supplied by the refrigerant supplier inside and outside the fuel cell.

[0093] The refrigerant supply unit is electrically connected to the control unit. The refrigerant supply unit is controlled by a control signal from the control unit. The flow rate of the refrigerant supplied to the fuel cell by the refrigerant supply unit is regulated by the control unit. This allows the temperature of the fuel cell to be controlled.

[0094] The refrigerant supplier includes, for example, a cooling water pump, but is not limited to that.

[0095] The refrigerant circulation flow path can be provided with a cooler to dissipate heat from the cooling water.

[0096] The refrigerant circulation flow path can be provided with a reserve tank for storing the refrigerant.

[0097] The fuel cell system can include a secondary cell.

[0098] The secondary cell (battery) can be any type of rechargeable and dischargeable cell. For example, it could be a conventional secondary cell such as a nickel-hydrogen secondary cell or a lithium-ion secondary cell. The secondary cell can include an energy storage element, such as an electrical double-layer capacitor. It can also be configured as a series-connected system. The secondary cell supplies power to the motor, the oxidizer gas supply, and other components. It can be recharged by an external power source, such as a household outlet. The secondary cell can also be charged by the fuel cell's output. The charging and discharging of the secondary cell can be controlled by the system's control unit.

[0099] The controller physically comprises a processing unit, such as a central processing unit (CPU), a storage device such as read-only memory (ROM) and random-access memory (RAM), and an input / output interface. The ROM is used to store a control program, control data, etc., to be processed by the CPU, and the RAM is primarily used as various workspaces for control processing. The controller can be a device such as an electronic control unit (ECU).

[0100] The control unit can be electrically connected to an ignition switch, which may be installed in the vehicle. The control unit can also be powered by an external power supply, even when the ignition switch is off. (1) First embodiment

[0101] The control system stores in advance the data group that specifies the ratio between the amount of hydrogen gas supplied and the hydrogen pressure increase rate when the predetermined amount of hydrogen gas is supplied by the fuel gas supplier.

[0102] The control system calculates the fuel gas pressure increase rate from the pressure change detected by the pressure sensor when the fuel gas is supplied to the fuel cell.

[0103] The control system determines whether the fuel gas pressure increase rate is lower than the hydrogen pressure increase rate or not.

[0104] If the control system determines that the fuel gas pressure increase rate is lower than the hydrogen pressure increase rate, the control system prevents the fuel cell from generating energy. (2) Second embodiment

[0105] The control system proactively stores the data group that indicates the hydrogen pressure after the predetermined period has elapsed, when the predetermined amount of hydrogen gas is supplied by the fuel gas supplier.

[0106] The control system determines whether the fuel gas pressure is lower than the hydrogen pressure after the predetermined period.

[0107] If the control system determines that the fuel gas pressure is lower than the hydrogen pressure after the predetermined period, the control system prevents the fuel cell from generating energy.

[0108] Fig. Figure 2 is a view showing an example of the relationship between the pressure of normal fuel gas containing no impurity gas and the injection time or spray time of the normal fuel gas into the fuel cell, and an example of the relationship between the pressure of abnormal fuel gas containing impurity gas and the injection time of the abnormal fuel gas into the fuel cell.

[0109] In the first embodiment, as in Fig. As shown in Figure 2, the presence or absence of the contaminant gas is determined by a difference in the gradient of the pressure increase rate. In the second embodiment, the presence or absence of the foreign gas is determined by a difference in pressure after the predetermined period has elapsed.

[0110] To increase the accuracy in determining the presence or absence of the contaminant gas, the first and second embodiments can be combined and carried out simultaneously. Of the first and second embodiments, the first embodiment can be carried out before the second embodiment, or the second embodiment can be carried out before the first embodiment.

[0111] Fig. Figure 3 is a schematic configuration diagram of a fuel cell system in the described embodiments.

[0112] A in Fig. The fuel cell system 100 shown in Figure 3 includes a fuel cell 10, a fuel gas supplier 20, a fuel gas supply flow path 21, an exhaust gas discharge flow path 22, a venting and discharge valve 23, a control unit 50, and a pressure sensor 60. Fig. Figure 3 only illustrates the fuel gas system, and other systems such as the oxidizer gas system and the cooling system are not illustrated.

[0113] The pressure sensor 60 is located on the fuel gas supply flow path 21 and measures the fuel gas pressure at the anode input. As indicated by a dashed line, the pressure sensor 60 is electrically connected to the controller 50 and transmits the measured fuel gas pressure value to the controller 50.

[0114] The control unit 50 is electrically connected to the fuel gas supplier 20 and controls the fuel gas supply from the fuel gas supplier 20 based on the result of the measurement of the fuel gas pressure value.

[0115] The control unit 50 is electrically connected to the venting and discharge valve 23. When necessary, it opens the venting and discharge valve 23 to release excess gas, water, and the like from the exhaust gas discharge flow path 22 to the outside.

[0116] Fig. Figure 4 is a schematic configuration diagram of another example of the fuel cell system of the disclosed embodiments.

[0117] The in Fig. The fuel cell system 200 shown in Figure 4 includes a fuel cell 10, a fuel gas supplier 20, a fuel gas supply flow path 21, an exhaust gas discharge flow path 22, a venting and discharge valve 23, an anode gas-liquid separator 24, a circulation flow path 25, an ejector 26, a controller 50, and a pressure sensor 60. Fig. Figure 4 illustrates only the fuel gas system; other systems, such as the oxidizer gas system and the cooling system, are not illustrated. Of the Fig. The four components shown are the same components as in Fig. 3 are shown and are not described here.

[0118] The anode gas-liquid separator 24 is located at the branch point of the exhaust gas discharge flow path 22 and the circulation flow path 25. It separates the fuel gas and the water from the exhaust gas, i.e., from the fuel gas discharged from the anode outlet, and returns the fuel gas as the circulation gas to the circulation flow path 25.

[0119] The ejector 26 is arranged at an intersection with the fuel gas supply flow path 21 of the circulation flow path 25.

[0120] Fig. Figure 5 is a schematic configuration diagram of another example of the fuel cell system of the disclosed embodiments. Of the in Fig. The 5 components shown are the same components as in Fig. 4 are shown and are not described here.

[0121] Compared to the one in Fig. The fuel cell system 200 shown in section 4 is located in the... Fig. In the fuel cell system 300 shown in Figure 5, a circulation pump 27 is arranged in the circulation flow path 25, instead of placing the ejector 26 at the intersection with the fuel gas supply flow path 21 of the circulation flow path 25. The ejector 26 can be arranged at the intersection with the fuel gas supply flow path 21 of the circulation flow path 25.

[0122] Fig. Figure 6 is a flowchart illustrating an example of the control of the fuel cell system of the disclosed embodiments. (A) First embodiment

[0123] The control system supplies the fuel cell with the predetermined amount of fuel gas. The point in time at which the fuel gas is supplied to the fuel cell can be, for example, after the fuel gas has been delivered to the fuel gas supplier.

[0124] The control system calculates the fuel gas pressure increase rate from the pressure change detected by the pressure sensor.

[0125] The control system determines whether the fuel gas pressure increase rate is lower than the previously stored hydrogen pressure increase rate or not.

[0126] If the control system determines that the fuel gas pressure increase rate is lower than the hydrogen pressure increase rate, it prevents the fuel cell from generating power. If the fuel gas pressure increase rate is lower than the hydrogen pressure increase rate, the irreversible power degradation of the fuel cell can be prevented by prohibiting its power generation, as the foreign gas is present in the fuel gas.

[0127] If, however, the control system determines that the fuel gas pressure increase rate is equal to or greater than the hydrogen pressure increase rate, the control system allows the fuel cell to generate energy.

[0128] Fig. Figure 7 is a flowchart illustrating another example of the control of the fuel cell system of the disclosed embodiments. (B) Second embodiment

[0129] The control system supplies the fuel cell with the predetermined amount of fuel gas.

[0130] Using the pressure sensor, the fuel gas pressure is recorded by the control unit after the predetermined period has elapsed.

[0131] The control system determines whether the fuel gas pressure after the predetermined period is lower than the previously stored hydrogen pressure after the predetermined period.

[0132] If the controller determines that the fuel gas pressure is lower than the pre-stored hydrogen pressure after the predetermined period, it prevents the fuel cell from generating power. If the fuel gas pressure is lower than the hydrogen pressure after the predetermined period due to the presence of foreign gas in the fuel gas, the irreversible power degradation of the fuel cell can be prevented by stopping its power generation.

[0133] If, however, the control system determines that the fuel gas pressure after the predetermined period is equal to or greater than the previously stored hydrogen pressure after the predetermined period, the control system allows the fuel cell to generate energy.

[0134] Fig. Figure 8 is a flowchart illustrating another example of the control of the fuel cell system of the disclosed embodiments. (C) First embodiment and second embodiment

[0135] The control system supplies the fuel cell with the predetermined amount of fuel gas.

[0136] The control system calculates the fuel gas pressure increase rate from the pressure change detected by the pressure sensor.

[0137] The control system determines whether the fuel gas pressure increase rate is lower than the previously stored hydrogen pressure increase rate or not.

[0138] If the control system determines that the fuel gas pressure increase rate is equal to or greater than the hydrogen pressure increase rate, the control system allows the fuel cell to generate energy.

[0139] If, however, the control system determines that the fuel gas pressure increase rate is lower than the hydrogen pressure increase rate, the fuel gas pressure is measured by the control system using the pressure sensor after the predetermined period has elapsed.

[0140] The control system determines whether the fuel gas pressure after the predetermined period is lower than the previously stored hydrogen pressure after the predetermined period.

[0141] If the control system determines that the fuel gas pressure after the predetermined period is lower than the previously stored hydrogen pressure after the predetermined period, the control system prevents the fuel cell from generating energy.

[0142] If, however, the control system determines that the fuel gas pressure after the predetermined period is equal to or greater than the previously stored hydrogen pressure after the predetermined period, the control system allows the fuel cell to generate energy.

[0143] By combining the first embodiment and the second embodiment, the accuracy of determining the presence or absence of the foreign gas can be increased.

[0144] Fig. Figure 9 is a flowchart illustrating another example of the control of the fuel cell system of the disclosed embodiments. (D) Second embodiment and first embodiment

[0145] The control system supplies the fuel cell with the predetermined amount of fuel gas.

[0146] The fuel gas pressure after the predetermined period has elapsed is detected by the control unit using the pressure sensor.

[0147] The control system determines whether the fuel gas pressure after the predetermined period is lower than the previously stored hydrogen pressure after the predetermined period.

[0148] If the control system determines that the fuel gas pressure after the predetermined period is equal to or greater than the previously stored hydrogen pressure after the predetermined period, the control system allows the fuel cell to generate energy.

[0149] If, however, the control system determines that the fuel gas pressure after the predetermined period is lower than the previously stored hydrogen pressure after the predetermined period, the control system calculates the fuel gas pressure increase rate from the pressure change detected by the pressure sensor.

[0150] The control system determines whether the fuel gas pressure increase rate is lower than the previously stored hydrogen pressure increase rate or not.

[0151] If the control system determines that the fuel gas pressure increase rate is lower than the hydrogen pressure increase rate, the control system prevents the fuel cell from generating energy.

[0152] If, however, the control system determines that the fuel gas pressure increase rate is equal to or greater than the hydrogen pressure increase rate, the control system allows the fuel cell to generate energy.

[0153] By combining the second embodiment and the first embodiments, the accuracy in determining the presence or absence of the foreign gas can be increased.

[0154] Fig. Figure 10 is a flowchart illustrating another example of the control of the fuel cell system of the disclosed embodiments. (E) First embodiment and second embodiment

[0155] The control system supplies the fuel cell with the predetermined amount of fuel gas.

[0156] The control system calculates the fuel gas pressure increase rate from the pressure change detected by the pressure sensor.

[0157] The control system determines whether the fuel gas pressure increase rate is lower than the previously stored hydrogen pressure increase rate or not.

[0158] If the control system determines that the fuel gas pressure increase rate is equal to or greater than the hydrogen pressure increase rate, the control system allows the fuel cell to generate energy.

[0159] If, however, the control system determines that the fuel gas pressure increase rate is lower than the hydrogen pressure increase rate, the control system suspends the fuel gas supply to the fuel cell and supplies the fuel cell with the predetermined amount of fuel gas again.

[0160] The control system recalculates the fuel gas pressure increase rate from the pressure change detected by the pressure sensor.

[0161] The control system determines again whether the fuel gas pressure increase rate is lower than the previously stored hydrogen pressure increase rate or not.

[0162] If the control system determines that the fuel gas pressure increase rate is equal to or greater than the hydrogen pressure increase rate, the control system allows the fuel cell to generate energy.

[0163] If, however, the control system determines that the fuel gas pressure increase rate is lower than the hydrogen pressure increase rate, the control system prevents the fuel cell from generating energy.

[0164] Considering the possibility of poor performance of the fuel gas supplier, the accuracy of determining the presence or absence of the foreign gas can be increased by attempting the fuel gas supply again (i.e., closing the main shut-off valve of the fuel gas supplier and then reopening the valve) and then making the determination.

[0165] Fig.Figure 11 is a flowchart illustrating another example of the control of the fuel cell system of the disclosed embodiments. (F) Second embodiment and second embodiment

[0166] The control system supplies the fuel cell with the predetermined amount of fuel gas.

[0167] The fuel gas pressure after the predetermined period has elapsed is detected by the control unit using the pressure sensor.

[0168] The control system determines whether the fuel gas pressure after the predetermined period is lower than the previously stored hydrogen pressure after the predetermined period.

[0169] If the control system determines that the fuel gas pressure after the predetermined period is equal to or greater than the previously stored hydrogen pressure after the predetermined period, the control system allows the fuel cell to generate energy.

[0170] If, however, the control system determines that the fuel gas pressure after the predetermined period is lower than the previously stored hydrogen pressure after the predetermined period, the control system suspends the fuel gas supply to the fuel cell and supplies the fuel cell with the predetermined amount of fuel gas again.

[0171] Based on the pressure change detected by the pressure sensor, the control unit recalculates the fuel gas pressure after the predetermined period has elapsed.

[0172] The control system determines again whether the fuel gas pressure after the predetermined period is lower than the previously stored hydrogen pressure after the predetermined period.

[0173] If the control system determines that the fuel gas pressure after the predetermined period is equal to or greater than the previously stored hydrogen pressure after the predetermined period, the control system allows the fuel cell to generate energy.

[0174] If, however, the control system determines that the fuel gas pressure after the predetermined period is lower than the previously stored hydrogen pressure after the predetermined period, the control system prevents the fuel cell from generating energy.

[0175] Considering the possibility of poor performance of the fuel gas supplier, the accuracy of determining the presence or absence of the foreign gas can be increased by attempting the fuel gas supply again (i.e., closing the main shut-off valve of the fuel gas supplier and then reopening the valve) and then making the determination. LIST OF SYMBOLS 10 Fuel cell 20 fuel gas suppliers 21 Fuel gas supply flow path 22 Exhaust gas discharge flow path 23 Venting and discharge valve 24 anode gas-liquid separator 25 Circulation flow path 26 Ejector 27 Circulation pump 50 Control 60 Pressure sensor 100 fuel cell systems 200 fuel cell systems 300 fuel cell systems

Claims

[1] Fuel cell system (100, 200, 300), wherein the fuel cell system (100, 200, 300) comprises: a fuel cell (10), a fuel gas supplier (20) for supplying hydrogen-containing fuel gas to the fuel cell (10), a fuel gas supply flow path (21) connecting a fuel gas inlet of the fuel cell (10) and the fuel gas supplier (20), a pressure sensor (60) which is arranged in the fuel gas supply flow path (21), an exhaust gas discharge flow path (22) for discharging the exhaust gas discharged from a fuel gas outlet of the fuel cell (10) to the outside of the fuel cell system (100, 200, 300), a venting and discharge valve (23) arranged in the exhaust gas discharge flow path (22), and a controller (50), wherein the controller (50) stores in advance a data set which specifies a relationship between a quantity of the supplied hydrogen gas and a hydrogen pressure increase rate when a predetermined quantity of hydrogen gas is supplied by the fuel gas supplier (20); wherein the controller (50) calculates a fuel gas pressure increase rate from a pressure change detected by the pressure sensor (60) when the fuel gas is supplied to the fuel cell (10); wherein the control (50) determines whether the fuel gas pressure increase rate is less than the hydrogen pressure increase rate or not; and wherein, if the controller (50) determines that the fuel gas pressure increase rate is less than the hydrogen pressure increase rate, the controller (50) prevents the fuel cell (10) from generating energy. [2] Fuel cell system (100, 200, 300) according to claim 1, wherein the controller (50) stores in advance a data group which indicates a hydrogen pressure after a predetermined period of time, when the predetermined quantity of hydrogen gas is supplied by the fuel gas supplier (20); wherein, if the controller (50) determines that the fuel gas pressure increase rate is less than the hydrogen pressure increase rate, the controller (50) determines whether the fuel gas pressure is less than the hydrogen pressure after the predetermined period or not; and wherein, if the controller (50) determines that the fuel gas pressure is lower than the hydrogen pressure after the predetermined period, the controller (50) prevents the fuel cell (10) from generating energy. [3] Fuel cell system (100, 200, 300), wherein the fuel cell system (100, 200, 300) comprises: a fuel cell (10), a fuel gas supplier (20) for supplying hydrogen-containing fuel gas to the fuel cell (10), a fuel gas supply flow path (21) connecting a fuel gas inlet of the fuel cell (10) and the fuel gas supplier (20), a pressure sensor (60) which is arranged in the fuel gas supply flow path (21), an exhaust gas discharge flow path (22) for discharging the exhaust gas discharged from a fuel gas outlet of the fuel cell (10) to the outside of the fuel cell system (100, 200, 300), a venting and discharge valve (23) arranged in the exhaust gas discharge flow path (22), and a controller (50), wherein the controller (50) stores in advance a data group which indicates a hydrogen pressure after a predetermined period of time when a predetermined quantity of hydrogen gas is supplied from the fuel gas supplier (20); wherein the control (50) determines whether the fuel gas pressure is lower than the hydrogen pressure after the predetermined period or not; and wherein, if the controller (50) determines that the fuel gas pressure is lower than the hydrogen pressure after the predetermined period, the controller (50) prevents the fuel cell (10) from generating energy. [4] Fuel cell system (100, 200, 300) according to claim 3, wherein the controller (50) stores in advance a data set which specifies a relationship between a quantity of hydrogen gas supplied and a hydrogen pressure increase rate when the predetermined quantity of hydrogen gas is supplied by the fuel gas supplier (20); wherein, if the controller (50) determines that the fuel gas pressure is less than a predetermined threshold after the elapsed period of time, the controller (50) calculates a fuel gas pressure increase rate from a pressure change detected by the pressure sensor (60) when the fuel gas is supplied to the fuel cell (10); wherein the control (50) determines whether the fuel gas pressure increase rate is less than the hydrogen pressure increase rate or not; and wherein, if the controller (50) determines that the fuel gas pressure increase rate is less than the hydrogen pressure increase rate, the controller (50) prevents the fuel cell (10) from generating energy.

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