Apparatus for reducing a hydrogen concentration in a fuel cell system and a method thereof

Abstract

Device for reducing an exhaust hydrogen concentration in a fuel cell system, the device comprising: a first air shutoff valve (ACV) configured to block ambient air supplied to a cathode; a second ACV configured to block exhaust hydrogen emitted from the cathode; an air intake valve (ASV) configured to operate in a first mode connecting the cathode and an inlet port of an air compressor and in a second mode blocking communication between the cathode and the inlet port of the air compressor; and a controller configured to operate the ASV in the first mode to store air from the cathode in an air tank while the first ACV is open and the second ACV is closed when hydrogen is supplied to an anode, and to operate the ASV in the second mode to exhaust the ambient air supplied to the cathode via an exhaust line while the first ACV remains open and the second ACV is open when the ambient air is supplied to the cathode.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a technique for reducing a concentration of hydrogen (exhaust hydrogen) discharged through an exhaust pipe from a cathode of a fuel cell stack. BACKGROUND

[0002] A fuel cell system is a type of power generation system that does not convert the chemical energy of the fuel into heat through combustion. A fuel cell system converts chemical energy directly into electrical energy in a fuel cell stack.

[0003] The fuel cell system largely includes a fuel cell stack that generates electrical energy, a hydrogen supply device that supplies hydrogen as fuel to the fuel cell stack, an air supply device that supplies air (oxygen), which is an oxidizer required for an electrochemical reaction, to the fuel cell stack, a thermal management system (TMS) that releases reaction heat of the fuel cell stack to the outside of the system and controls an operating temperature of the fuel cell stack to perform water management functions, and a fuel cell system controller that controls an overall operation of the fuel cell system.

[0004] The fuel cell system described above generates electricity by reacting hydrogen, which is a fuel, with oxygen in the air and releases heat and water as reaction byproducts.

[0005] The most popular type of fuel cell for a vehicle is a proton exchange membrane fuel cell (PEMFC) (or a polymer electrolyte membrane fuel cell), which has the highest power density among fuel cells and features a fast start-up time and fast power conversion response time due to a low operating temperature.

[0006] The fuel cell stack assembled in the proton exchange membrane fuel cell includes a membrane-electrode assembly (MEA), which includes a polymer electrolyte membrane in which hydrogen ions move, and catalyst layers attached to opposite sides of the polymer electrolyte membrane where an electrochemical reaction takes place. The fuel cell stack also includes a gas diffusion layer (GDL), which serves to evenly distribute reactant gases and transfer generated electricity, and a gasket and fastener to maintain airtightness and the correct contact pressure of reactant gases and cooling water. The fuel cell stack also includes a bipolar plate to move the reactant gases and cooling water and to generate current through a fuel cell reaction that supplies hydrogen and oxygen.

[0007] The fuel cell system should keep the concentration of hydrogen gas in the exhaust gas below a certain reference value to minimize the risk of explosion or fire due to the hydrogen gas contained in the exhaust gas.

[0008] However, the hydrogen gas discharged through a hydrogen purge valve of the fuel cell system and the hydrogen gas generated in a cathode due to a crossover phenomenon may be discharged through an exhaust pipe. The crossover phenomenon refers to a phenomenon in which hydrogen gas from an anode diffuses due to a difference in gas concentration between the anode and the cathode in the fuel cell stack.

[0009] According to a Global Technical Regulation (GTR) currently in use worldwide, a permissible concentration of hydrogen gas emitted by a fuel cell system should be less than 8%, and an average concentration measured over 3 seconds should not exceed 4%.

[0010] Accordingly, a fuel cell vehicle using hydrogen as fuel should always emit exhaust gas with a hydrogen concentration below a certain level or value under all operating conditions.

[0011] The above information disclosed in this section is provided only to enhance the understanding of the background of the disclosure and may therefore contain information that does not constitute prior art already known to a person of ordinary skill in the art in this country. SUMMARY

[0012] The present disclosure has been made to solve the above-mentioned problems encountered in the prior art while keeping intact the advantages achieved by the prior art.

[0013] One aspect of the present disclosure provides an apparatus and method for reducing an exhaust hydrogen concentration in a fuel cell system, capable of reducing the hydrogen concentration in air discharged through an exhaust passage when hydrogen is supplied to a fuel cell stack, an air cut-off valve (ACV) adjacent to an inlet of a cathode is opened, an ACV adjacent to an outlet of the cathode is closed, and an air suction valve (ASV) is operated in a first mode to store cathode air in an air tank. When ambient air is supplied to the cathode, the ACV adjacent to the inlet of the cathode maintains an open state, the ACV adjacent to the outlet of the cathode is opened, and the ASV is operated in a second mode to discharge the ambient air supplied to the cathode to the outside through the exhaust passage.

[0014] The technical problems to be solved by the present disclosed concept are not limited to the aforementioned problems, and any other technical problems not mentioned herein will be clearly understood from the following description by a person skilled in the art to which the present disclosure relates.

[0015] According to one aspect of the present disclosure, an apparatus for reducing an exhaust hydrogen concentration in a fuel cell system may include a first air cut-off valve (ACV) that blocks ambient air supplied to a cathode, a second ACV that blocks exhaust hydrogen discharged from the cathode, and an air suction valve (ASV) that operates in a first mode connecting the cathode and an inlet port of an air compressor and operates in a second mode blocking communication between the cathode and the inlet port of the air compressor.The apparatus may also include a controller that operates the ASV in the first mode to store air of the cathode while opening the first ACV and closing the second ACV when hydrogen is supplied to an anode, and operates the ASV in the second mode to exhaust the ambient air supplied to the cathode via an exhaust line while keeping the first ACV open and opening the second ACV when ambient air is supplied to the cathode.

[0016] The air compressor can draw in the air from the cathode to store the air in an air tank when the ASV is operating in the first mode. The controller can control the air compressor to draw in the air from the cathode for a reference time. Furthermore, the controller can control the air compressor to store the ambient air in the air tank.

[0017] The apparatus for reducing an exhaust hydrogen concentration in a fuel cell system may further comprise a concentration sensor disposed in the exhaust line connecting the cathode to the second ACV to measure a concentration of hydrogen in the cathode.

[0018] The controller may allow the hydrogen concentration in the cathode to be reduced when the hydrogen concentration measured by the concentration sensor exceeds a reference concentration.

[0019] The device for reducing an exhaust hydrogen concentration in a fuel cell system may further include a pressure sensor that measures a pressure of the air tank and an air exhaust valve (AEV) that discharges air in the air tank to the outside of the air tank.

[0020] The controller may allow the AEV to be opened to reduce the pressure of the air tank when the pressure measured by the pressure sensor exceeds a reference pressure.

[0021] According to one aspect of the present disclosure, a method for reducing an exhaust hydrogen concentration in a fuel cell system may include connecting a cathode to an inlet port of an air compressor while a first air shutoff valve (ACV) is opened and a second ACV is closed when hydrogen is supplied to an anode, operating the air compressor to store air of the cathode in an air tank, and blocking a connection between the cathode and the inlet port of the air compressor while the first ACV remains open and the second ACV is open when ambient air is supplied to the cathode to discharge the ambient air supplied to the cathode via an exhaust line.

[0022] Storing the cathode air in the air tank can operate the air compressor for a reference time.

[0023] Furthermore, connecting the cathode to the inlet port of the air compressor may comprise measuring a concentration of hydrogen in the cathode and connecting the cathode to the inlet port of the air compressor while the first ACV is open and the second ACV is closed when the measured hydrogen concentration exceeds a reference concentration.

[0024] Furthermore, storing the air of the cathode in the air tank may further comprise measuring a pressure of the air tank and discharging the air in the air tank to the outside of the air tank when the measured pressure exceeds a reference pressure.

[0025] According to one aspect of the present disclosure, a method for reducing an exhaust hydrogen concentration in a fuel cell system may include connecting a cathode to an inlet port of an air compressor while a first air shutoff valve (ACV) is opened and a second ACV is closed when hydrogen is supplied to an anode, lowering a pressure of an air tank to a reference pressure, operating the air compressor to store air of the cathode in the air tank, blocking a connection between the cathode and the inlet port of the air compressor while the first ACV remains open and the second ACV is open when ambient air is supplied to the cathode to discharge the ambient air supplied to the cathode via an exhaust line, and connecting the inlet port of the air compressor to the ambient air.

[0026] Storing the cathode air in the air tank can operate the air compressor for a reference time.

[0027] Furthermore, connecting the cathode to the inlet port of the air compressor may further comprise supplying hydrogen to the anode, measuring a concentration of hydrogen in the cathode, and connecting the cathode and the inlet port of the air compressor while the first ACV is opened and the second ACV is closed when the measured hydrogen concentration exceeds a reference concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other objects, features and other advantages of the present disclosure will become more clearly understood from the following detailed description taken in conjunction with the accompanying drawings: Fig. 1 shows a block diagram of an apparatus for reducing an exhaust hydrogen concentration in a fuel cell system according to an embodiment of the present disclosure; Fig. 2 shows the flowchart for a method for reducing an exhaust hydrogen concentration in a fuel cell system according to an embodiment of the present disclosure; Fig. 3 shows the flowchart for a method for reducing an exhaust hydrogen concentration in a fuel cell system according to another embodiment of the present disclosure; and Fig. 4 shows a block diagram illustrating a computer system for performing a method for reducing an exhaust hydrogen concentration in a fuel cell system according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the drawings. When adding reference numerals to the components of each drawing, it should be noted that the identical or equivalent component is identified by the identical numeral even if indicated in other drawings. Furthermore, in describing the embodiments of the present disclosure, a detailed description of well-known features or functions is excluded in order not to unnecessarily obscure the essence of the present disclosure.

[0030] In describing the components of the embodiment according to the present disclosure, terms such as first, second, "A," "B," (a), (b), and the like may be used. These terms are merely intended to distinguish one component from another, and the terms do not limit the type, sequence, or order of the constituent components. Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meanings as those commonly understood by one of ordinary skill in the art to which this disclosure relates. Such terms, as defined in a commonly used dictionary, should be interpreted to have meanings consistent with the meanings of the contexts in the relevant prior art field.Such terms should not be construed as having ideal or overly formal meanings unless clearly defined in the present application.

[0031] Fig. 1 shows a block diagram of an apparatus for reducing an exhaust hydrogen concentration in a fuel cell system according to an embodiment of the present disclosure.

[0032] As in Fig. 1, an apparatus 300 for reducing an exhaust hydrogen concentration in a fuel cell system according to an embodiment of the present disclosure may include a storage device 10, a concentration censor 20, an air shut-off valve 1 (ACV1) 30, an ACV2 40, an air intake valve (ASV) 50, an air compressor 60, an air tank 70, a pressure sensor 71, an air exhaust valve (AEV) 80, and a controller 90. In this example, each component may be combined to be implemented as one, or some components may be omitted depending on a method of implementing the apparatus 300 for reducing an exhaust hydrogen concentration in the fuel cell system according to an embodiment of the present disclosure.

[0033] The components described above will be described, respectively. The storage device 10 can store various logic, algorithms, and programs required in a process in which, when hydrogen is supplied to a fuel cell stack 200, the ACV1 30 is opened, the ACV2 40 is closed, and the ASV 50 operates in a first mode to store air from the cathode in the air tank 70. When ambient air is supplied to the cathode, the ACV1 30 maintains the open state, the ACV2 40 is opened, and the ASV 50 operates in a second mode to exhaust the ambient air supplied to the cathode to the outside via an exhaust conduit. In this example, the exhaust conduit means a passage from an output port of the cathode to the outside (i.e., outside the device 300) through the ACV2 40.

[0034] When hydrogen is supplied to the fuel cell stack 200, the storage device 10 may store a reference concentration value (e.g., 1%), which is used as a condition for determining whether or not to reduce the hydrogen concentration in the cathode. The reference concentration value may be set to a value that can meet GTR (Global Technical Regulation) regulations.

[0035] The storage device 10 can store a reference pressure value (e.g., 9.5 bar) that is used as a condition for determining whether air is discharged into the air tank 70. The air tank 70 has a suitable pressure (e.g., 10 bar).

[0036] The storage device 10 may store a reference time (e.g., 10 seconds) for limiting a time for operating the ASV 50 in the first mode.

[0037] The storage device 10 may include at least one type of storage medium of a memory including a flash memory type, a hard disk type, a micro type, and a card type (e.g., an SD (Secure Digital) card or an XD (Extreme Digital) card), and a random access memory (RAM), a static RAM (SRAM), a read-only memory (ROM), a programmable ROM (PROM), an electrically erasable PROM (EEPROM), a magnetic RAM (MRAM), a magnetic disk, and an optical disk.

[0038] The concentration center 20 may be arranged in the exhaust line connecting the cathode of the fuel cell stack 200 to the ACV2 40 to measure the hydrogen concentration in the cathode.

[0039] The ACV1 30 may serve to block the ambient air supplied to the cathode of the fuel cell stack 200.

[0040] The ACV2 40 may serve to block the exhaust hydrogen emitted from the cathode of the fuel cell stack 200.

[0041] The ASV 50 can operate in the first mode connecting the cathode of the fuel cell stack 200 to the inlet port of the air compressor 60 or in the second mode blocking the connection between the cathode of the fuel cell stack 200 and the inlet port of the air compressor 60.

[0042] When an embodiment of the present disclosure is applied to a bus or truck, the ASV 50, which is a three-way valve, may operate in the first mode connecting the cathode of the fuel cell stack 200 to the inlet port of the air compressor 60, or in the second mode connecting the ambient air to the inlet port of the air compressor 60. In this example, the ASV 50 may be configured as a first valve connecting the cathode of the fuel cell stack 200 to the inlet port of the air compressor 60 and a second valve connecting the ambient air to the inlet port of the air compressor 60.

[0043] The air compressor 60 may be configured to draw air from the cathode of the fuel cell stack 200 and store the air in the air tank 70 when the ASV 50 is operating in the first mode, and may be configured to draw ambient air and store the ambient air in the air tank 70 when the ASV 50 is operating in the second mode. When an embodiment of the present disclosure is applied to a bus or truck, the air compressor 60 may be embodied as an air compressor that supplies compressed air within the bus or truck.

[0044] The air tank 70 may serve to store the air supplied by the air compressor 60 into the cathode of the fuel cell stack 200 or the ambient air. When an embodiment of the present disclosure is applied to a bus or truck, the air tank 70 may be implemented as an air tank that stores compressed air in the bus or truck.

[0045] The pressure sensor 71 may measure a pressure of the air tank 70. When an embodiment of the present disclosure is applied to a bus or truck, the pressure sensor 71 may be embodied as a sensor for measuring a pressure of compressed air in the bus or truck.

[0046] The AEV 80 may vent the air in the air tank 70 to the outside. When an embodiment of the present disclosure is applied to a bus or truck, the AEV 80 may be embodied as a valve that supplies pressurized air to a braking system in the bus or truck.

[0047] The controller 90 performs overall control so that each component is able to perform its functions normally. The controller 90 may be implemented in a form of hardware, software, or a combination of hardware and software. The controller 90 may be implemented, in a non-limiting manner, as a microprocessor.

[0048] In particular, the controller 90 may perform various controls in a process in which, when the hydrogen is supplied to the fuel cell stack 200 (ie, when the hydrogen is supplied to an anode), the ACV1 30 is opened, the ACV2 40 is closed, and the ASV 50 operates in the first mode to store the air of the cathode in the air tank 70, and in which, when the ambient air is supplied to the cathode, the ACV1 30 remains open, the ACV2 40 is opened, and the ASV 50 operates in the second mode to discharge the ambient air supplied to the cathode to the outside via the exhaust pipe.

[0049] When the controller 90 receives a start command of the fuel cell system from a user, the controller 90 may control a hydrogen supply device 100 to supply the hydrogen to the fuel cell stack 200. In this example, the hydrogen supply device 100 may include a fuel block valve (FBV) 110, a fuel supply valve (FSV) 120, a fuel ejector (FEJ) 130, a fuel pressure sensor (FP10) 140, a fuel-line purge valve (FPV) 150, a fuel-line water trap (FWT) 160, a fuel-line level sensor (FL20) 170, and a fuel-line drain valve (FDV) 180.

[0050] The FBV 110 serves to block the hydrogen supplied to the fuel cell stack 200.

[0051] The FSV 120 serves to regulate a hydrogen pressure supplied to the fuel cell stack 200.

[0052] The FEJ 130 serves to recycle the hydrogen from the anode in the fuel cell stack 200.

[0053] The FP 1040, which is a pressure sensor, is used to measure the hydrogen pressure supplied to the fuel cell stack 200.

[0054] The FPV 150 serves to remove condensate and contaminants from the anode in the fuel cell stack 200.

[0055] The FWT 160 serves to store the condensate of the anode in the fuel cell stack 200.

[0056] The FL20 170, which is a water level sensor, is used to measure the water level of the condensate stored in the FWT 160.

[0057] The controller 90 may start a process for reducing the concentration of hydrogen in the cathode of the fuel cell stack 200 when the hydrogen is supplied to the fuel cell stack 200.

[0058] The controller 90 may start the process of reducing the hydrogen concentration in the cathode of the fuel cell stack 200 based on the measured value of the concentration sensor 20. When the hydrogen concentration in the cathode of the fuel cell stack 200 measured by the concentration sensor 20 exceeds the reference concentration (e.g., 1%), the controller 90 may start the process of reducing the hydrogen concentration in the cathode of the fuel cell stack 200.

[0059] To reduce the hydrogen concentration in the cathode of the fuel cell stack 200, the controller 90 may allow the ACV1 30 to open, the ACV2 40 to close, and the ASV 50 to operate in the first mode. The controller 90 may then operate the air compressor 60 to store the air (including the hydrogen) within the cathode of the fuel cell stack 200 in the air tank 70.

[0060] When the pressure of the air tank 70 exceeds the reference pressure, the controller 90 may open the AEV 80 to allow the pressure of the air tank 70 to be reduced (e.g., 7 to 10%).

[0061] When an embodiment of the present disclosure is applied to a bus or a truck, when the concentration of hydrogen in the cathode of the fuel cell stack 200 is reduced, the controller 90 may open the AEV 80 to lower the pressure of the air tank 70 to a threshold value, considering that the air tank always maintains an appropriate pressure. In other words, the controller 90 may secure a space in the air tank 70 in advance for storing the air of the cathode of the fuel cell stack 200.

[0062] When ambient air is supplied to the cathode of the fuel cell stack 200, the controller 90 may allow the ASV 50 to operate in the second mode while keeping the ACV 1 open and opening the ACV 2 to exhaust the air supplied to the cathode to the outside via the exhaust conduit. The controller 90 may further control an air compressor (not shown) for supplying the ambient air to the cathode of the fuel cell stack 200.

[0063] Fig. 2 shows the flowchart for a method for reducing an exhaust hydrogen concentration in a fuel cell system according to an embodiment of the present disclosure.

[0064] First, when hydrogen is supplied to the anode, the controller 90 connects the cathode to the inlet port of the air compressor 60 in 201, while ACV1 30 is opened and ACV2 40 is closed.

[0065] Thereafter, the controller 90 operates the air compressor 60 to store the cathode air in the air tank 70 in 202. In this example, the air tank 70 is connected to an outlet port of the air compressor 60.

[0066] Then, when the ambient air is supplied to the cathode, the controller 90 blocks the connection between the cathode and the inlet port of the air compressor 60 to discharge the ambient air supplied to the cathode via the exhaust line in 203, while ACV1 30 remains open and ACV2 40 is opened.

[0067] Fig. 3 shows the flowchart for a method for reducing an exhaust hydrogen concentration in a fuel cell system according to another embodiment of the present disclosure and shows a case applied to a bus or a truck.

[0068] First, when hydrogen is supplied to the anode, the controller 90 connects the cathode to the inlet port of the air compressor 60 in 301, while ACV1 30 is opened and ACV2 40 is closed.

[0069] Thereafter, the controller 90 opens the AEV 80 to reduce a pressure of the air tank to the reference pressure in 302.

[0070] Then, the controller 90 operates the air compressor 60 to store the air of the cathode in the air tank 70 in 303. The air stored in the air tank 70 can be used in a system that requires compressed air (e.g., a braking system) in a bus or a truck.

[0071] Thereafter, when the ambient air is supplied to the cathode, the controller 90 blocks the connection between the cathode and the inlet port of the air compressor 60 to discharge the ambient air supplied to the cathode via the exhaust line in 304, while ACV1 30 remains open and ACV2 40 is opened.

[0072] Then, the controller 90 connects the inlet port of the air compressor 60 to the ambient air at 305. In this example, the air compressor 60 is a module for generating compressed air in a bus or truck. The controller 90 connects the inlet port of the air compressor 60 to ambient air to perform its original function.

[0073] Fig. 4 illustrates a computer system executing a method for reducing an exhaust hydrogen concentration in a fuel cell system according to an embodiment of the present disclosure.

[0074] With reference to Fig. 4, a computer system 1000 may include at least a processor 1100, a memory 1300, a user interface input device 1400, a user interface output device 1500, storage 1600, and a network interface 1700 interconnected via a system bus 1200.

[0075] Processor 1100 may be a central processing unit (CPU) or a semiconductor device that processes instructions stored in memory 1300 and / or storage 1600. Memory 1300 and storage 1600 may include various types of volatile or non-volatile storage media. For example, memory 1300 may include read-only memory (ROM) and random access memory (RAM).

[0076] Thus, the operations of the method or algorithm described in connection with the embodiments of the present disclosure may be performed directly by hardware or a software module executed by a processor 1100, or a combination thereof. The software module may be located in a storage medium (e.g., memory 1300 and / or storage 1600), such as RAM, flash memory, ROM, EPROM, EEPROM, register, hard disk, solid state drive (SSD), removable disk, or CD-ROM. The exemplary storage medium is coupled to the processor 1100, and the processor 1100 may read information from and write information to the storage medium. Alternatively, the storage medium may be integrated with the processor 1100.The processor and storage medium may be located in an application-specific integrated circuit (ASIC). The ASIC may be located in a user terminal. Alternatively, the processor and storage medium may be located as a single component in the user terminal.

[0077] In the apparatus for reducing the exhaust hydrogen concentration in the fuel cell system and the method thereof according to an embodiment of the present disclosure, when the hydrogen is supplied to the fuel cell stack, the ACV adjacent to the inlet of the cathode may be opened, the ACV adjacent to the outlet of the cathode may be closed, and the ASV may be operated in the first mode to store the air of the cathode in the air tank. When the ambient air is supplied to the cathode, the ACV adjacent to the inlet of the cathode may remain open, the ACV adjacent to the outlet of the cathode may be opened, and the ASV may be operated in the second mode to discharge the ambient air supplied to the cathode to the outside via the exhaust pipe, thereby reducing the hydrogen concentration in the air discharged via the exhaust pipe.

[0078] Accordingly, the embodiments of the present disclosure are provided to illustrate, but not limit, the teachings and scope of the present disclosure, so that the teachings and scope of the present disclosure are not limited by the embodiments. The scope of the present disclosure should be interpreted based on the appended claims, and all technical ideas or concepts within the scope corresponding to the claims should be included in the scope of the present disclosure. Fig. 1 10 STORAGE DEVICE 20 CONCENTRATION SENSOR 60 AIR COMPRESSOR 71 PRESSURE SENSOR 90 CONTROL Fig. 2 201 Connect cathode and air compressor inlet port while ACV1 is open and ACV2 is closed when hydrogen is supplied to anode 202 Operate air compressor to store cathode air in the air tank 203 BLOCK THE CONNECTION BETWEEN THE CATHODE AND THE AIR COMPRESSOR INLET FOR DISCHARGING THE AMBIENT AIR SUPPLIED TO THE CATHODE VIA THE EXHAUST PIPE, WHILE ACV1 REMAINS OPEN AND ACV2 IS OPEN WHEN AMBIENT AIR IS SUPPLIED TO THE CATHODE. Fig. 3 301 Connecting the cathode to the air compressor inlet port while ACV1 is open and ACV2 is closed when hydrogen is supplied to the anode 302 OPEN AEV TO REDUCE AIR TANK PRESSURE TO REFERENCE PRESSURE 303 Operate air compressor to store cathode air in the air tank 304 BLOCK THE CONNECTION BETWEEN THE CATHODE AND THE AIR COMPRESSOR INLET PORT FOR DISCHARGING THE AMBIENT AIR SUPPLIED TO THE CATHODE VIA THE EXHAUST PIPE, WHILE ACV1 REMAINS OPEN AND ACV2 IS OPEN WHEN AMBIENT AIR IS SUPPLIED TO THE CATHODE. 305 Connect the air compressor inlet to ambient air Fig. 4 1100 PROCESSOR 1300 STORAGE 1400 User Interface Input Device 1500 User Interface Dispensing Device 1600 STORAGE 1700 NETWORK INTERFACE

Claims

[1] A device for reducing an exhaust hydrogen concentration in a fuel cell system, the device comprising: a first air shutoff valve (ACV) configured to block ambient air supplied to a cathode; a second ACV configured to block exhaust hydrogen emitted from the cathode; an air intake valve (ASV) configured to operate in a first mode connecting the cathode and an inlet port of an air compressor and in a second mode blocking communication between the cathode and the inlet port of the air compressor; and a controller configured to operate the ASV in the first mode to store air from the cathode in an air tank while the first ACV is open and the second ACV is closed when hydrogen is supplied to an anode, and to operate the ASV in the second mode to exhaust the ambient air supplied to the cathode via an exhaust line while the first ACV remains open and the second ACV is open when the ambient air is supplied to the cathode. [2] The apparatus of claim 1, wherein the air compressor draws air from the cathode to store the air in the air tank when the ASV operates in the first mode. [3] The apparatus of claim 2, wherein the controller controls the air compressor to suck the air of the cathode for a reference time. [4] The apparatus of claim 2, wherein the controller controls the air compressor to store the ambient air in the air tank. [5] The device of claim 1, further comprising: a concentration sensor disposed in the exhaust line connecting the cathode to the second ACV to measure a concentration of hydrogen in the cathode. [6] The apparatus of claim 5, wherein the controller allows the hydrogen concentration in the cathode to be reduced when the hydrogen concentration measured by the concentration sensor exceeds a reference concentration. [7] The device of claim 1, further comprising: a pressure sensor for measuring a pressure of the air tank; and an air exhaust valve (AEV) for discharging air in the air tank to the outside of the air tank. [8] The apparatus of claim 7, wherein the controller allows the AEV to be opened to reduce the pressure of the air tank when the pressure measured by the pressure sensor exceeds a reference pressure. [9] A method for reducing an exhaust hydrogen concentration in a fuel cell system, the method comprising: Connecting a cathode to an inlet port of an air compressor while a first air shutoff valve (ACV) is open and a second ACV is closed when hydrogen is supplied to an anode; Operating the air compressor to store cathode air in an air tank; and Blocking a connection between the cathode and the inlet port of the air compressor while the first ACV remains open and the second ACV is open when ambient air is supplied to the cathode to discharge the ambient air supplied to the cathode via an exhaust line. [10] The method of claim 9, wherein storing the air of the cathode in the air tank operates the air compressor for a reference time. [11] The method of claim 9, wherein connecting the cathode to the inlet port of the air compressor comprises: Measuring a hydrogen concentration in the cathode; and Connecting the cathode and the inlet port of the air compressor while the first ACV is open and the second ACV is closed when the measured concentration of hydrogen exceeds a reference concentration. [12] The method of claim 9, wherein storing the air of the cathode in the air tank comprises: Measuring a pressure of the air tank; and Discharge the air in the air tank to the outside of the air tank when the measured pressure exceeds a reference pressure. [13] A method for reducing an exhaust hydrogen concentration in a fuel cell system, the method comprising: Connecting a cathode to an inlet port of an air compressor while a first air shutoff valve (ACV) is open and a second ACV is closed when hydrogen is supplied to an anode; and Lowering the pressure of an air tank to a reference pressure; Operating the air compressor to store cathode air in the air tank; Blocking a connection between the cathode and the inlet port of the air compressor while the first ACV remains open and the second ACV is open when ambient air is supplied to the cathode to discharge the ambient air supplied to the cathode via an exhaust line; and Connecting the air compressor inlet to the ambient air. [14] The method of claim 13, wherein storing the air of the cathode in the air tank operates the air compressor for a reference time. [15] The method of claim 13, wherein connecting the cathode to the inlet port of the air compressor comprises: Supplying the hydrogen to the anode; Measuring a hydrogen concentration in the cathode; and Connecting the cathode and the inlet port of the air compressor while the first ACV is open and the second ACV is closed when the measured hydrogen concentration exceeds a reference concentration.

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