Fuel cell system and control method thereof

Abstract

The present invention provides a fuel cell system and a method for controlling the fuel cell system. The method includes, when starting a fuel cell stack, obtaining the flow rate of air supplied to the cathode after opening an air conditioner for regulating air supplied to the cathode. Then, the sealing state of the fuel cell stack is determined based on the obtained flow rate of air.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority from Korean Patent Application No. 10-2018-0140195, filed on November 14, 2018, which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present invention relates to a fuel cell system and a control method thereof, and more particularly, to a fuel cell system for determining a sealing state of a fuel cell stack based on air flow and a method for controlling the fuel cell system. Background Art

[0004] Fuel cell systems that continuously generate electrical energy through electrochemical reactions of continuously supplied fuel have been studied and developed as an alternative solution to global environmental problems. Fuel cell systems can be divided into phosphoric acid fuel cells (PAFC), molten carbonate fuel cells (MCFC), solid oxide fuel cells (SOFC), polymer electrolyte membrane fuel cells (PEMFC), alkaline fuel cells (AFC) and direct methanol fuel cells (DMFC) according to the type of electrolyte used. Fuel cell systems can be applied to various applications such as mobile power, transportation, distributed power generation, etc., depending on the operating temperature and output range and the type of fuel used.

[0005] Among the above-mentioned fuel cells, PEMFC is applied to hydrogen-powered vehicles (hydrogen fuel cell vehicles) being developed to replace internal combustion engines. Hydrogen-powered vehicles are driven by generating electricity through an electrochemical reaction of hydrogen and oxygen and operating an electric motor using the generated electricity. Hydrogen-powered vehicles have a structure including a hydrogen tank (H2 tank) for storing hydrogen (H2), a fuel cell stack (FC stack) for generating electricity through an oxidation / reduction reaction of hydrogen (H2) and oxygen (O2), various devices for discharging the generated water, a battery for storing the electricity generated by the fuel cell stack, a controller for converting and regulating the generated electricity, an electric motor for generating a driving force, and the like.

[0006] A fuel cell stack refers to a fuel cell body having dozens or hundreds of cells stacked in series. A fuel cell stack has a structure in which a plurality of cells are stacked between end plates, each cell including an electrolyte membrane that divides the interior of the cell into two parts, an anode on a first side of the electrolyte membrane, and a cathode on a second side thereof. A separator is provided between the cells to restrict the flow path of hydrogen and oxygen. The separator is made of a conductor to move electrons during the oxidation / reduction reaction.

[0007] When hydrogen is supplied to the anode, the hydrogen is separated into hydrogen ions and electrons by the catalyst. The electrons generate electricity when they move through the separator to the outside of the fuel cell stack. The hydrogen ions pass through the electrolyte membrane and move to the cathode, after which the hydrogen ions combine with oxygen and electrons provided from the ambient air to generate water, and the generated water is discharged to the outside.

[0008] In a fuel cell system, it is important to maintain the airtightness of the fuel cell stack. When the fuel cell stack starts to operate and air is accidentally introduced into the fuel cell stack due to its poor sealing state when the fuel cell stack is stopped, an excessively high voltage may be generated in the fuel cell stack, and thus the fuel cell stack may be damaged. Therefore, a technology for directly detecting the sealing performance of the fuel cell stack is required. Summary of the invention

[0009] The present invention provides a fuel cell system for directly detecting the sealing performance of a fuel cell stack when the fuel cell system starts to operate, and a method for controlling the fuel cell system. Another aspect of the present invention provides a fuel cell system for effectively detecting a poor sealing state of a fuel cell stack to prevent excessive voltage from being generated in the fuel cell stack or to prevent the high voltage from being maintained even if a high voltage is generated, thereby preventing damage to the fuel cell system, and a method for controlling the fuel cell system.

[0010] The technical problems to be solved by the present invention are not limited to the above-mentioned problems, and any other technical problems not mentioned herein will be clearly understood by those skilled in the art to which the present invention belongs from the following description.

[0011] According to one aspect of the present invention, a method for controlling a fuel cell system may include: when the fuel cell stack is started, immediately obtaining the flow rate of air supplied to the cathode after an air regulator for regulating the air supplied to the cathode is opened, and determining the sealing state of the fuel cell stack based on the obtained air flow rate.

[0012] According to another aspect of the present invention, a fuel cell system may include: at least one processor; an air flow acquisition device connected to the at least one processor and configured to obtain the flow of air supplied to the cathode; and a memory connected to the at least one processor and configured to store a plurality of instructions. When the instructions are executed, the processor operates the air flow acquisition device to obtain the flow of air supplied to the cathode immediately after the air regulator for regulating the air supplied to the cathode is turned on when the fuel cell stack is started, and determines the sealing state of the fuel cell stack based on the obtained air flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The above and other objects, features and advantages of the present invention will become more apparent through the following detailed description in conjunction with the accompanying drawings:

[0014] Figure 1 is a block diagram showing a fuel cell system according to an exemplary embodiment of the present invention;

[0015] Figure 2 is a flow chart illustrating a method for controlling a fuel cell system according to an exemplary embodiment of the present invention;

[0016] Figure 3 is a diagram showing an exemplary embodiment according to the present invention Figure 2 A view of step S400 of ; and

[0017] Figure 4A , Figure 4B , Figure 5A and Figure 5B is a view illustrating the operation of a method for controlling a fuel cell system according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0018] It is understood that the term "vehicle" or "vehicle-related" or other similar terms used herein generally include motor vehicles, such as sports utility vehicles (SUVs), buses, trucks, various commercial vehicles; ships including various boats, vessels, aircraft, etc., and include hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuels from non-petroleum resources). As mentioned herein, a hybrid vehicle is a vehicle with two or more power sources, such as a vehicle that has both gasoline power and electric power.

[0019] Although the exemplary embodiments are described as using multiple units to perform the exemplary processes, it should be understood that the exemplary processes can also be performed by one or more modules. In addition, it should be understood that the term controller / control unit refers to a hardware device including a memory and a processor. The memory is configured to store the modules, and the processor is specifically configured to execute the modules to perform one or more processes described further below.

[0020] In addition, the control logic of the present invention may be embodied as a non-transitory computer-readable medium on a computer-readable medium containing executable program instructions executed by a processor, a controller / control unit, etc. Examples of computer-readable media include, but are not limited to, ROM, RAM, compact disk (CD)-ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage device. The computer-readable medium may also be distributed in a network-connected computer system so that the computer-readable medium is stored and executed in a distributed manner, such as by a telematics server or a controller area network (CAN).

[0021] The terms used herein are only used to illustrate specific embodiments and are not intended to limit the present invention. As used herein, the singular forms "a", "an" and "the" are also intended to include plural forms unless the context clearly indicates. It is further understood that when "including" and / or "comprising" are used in this specification, it refers to the presence of stated features, integers, steps, operations, elements and / or parts, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or combinations thereof. As used herein, the word "and / or" includes any and all combinations of one or more related listed items.

[0022] Unless otherwise specified or apparent from the context, the word "about" as used herein is understood to be within the normal tolerance range in the art, such as within two standard deviations of the mean. "About" may be understood to be within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05% or 0.01% of the specified value. Unless the context clearly indicates otherwise, all numerical values ​​herein are modified by the word "about".

[0023] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood that even if shown in different drawings, the same components have the same reference numerals in the drawings. In addition, when describing exemplary embodiments of the present invention, detailed descriptions related to well-known functions or configurations will be omitted to avoid unnecessarily obscuring the subject matter of the present invention.

[0024] Words such as "first", "second", "A", "B", "(a)", "(b)", etc. may be used herein to describe components in embodiments of the present invention. These words are only used to distinguish one component from another, and the nature, sequence, order or number of these components are not limited by these words. If a component is described as being "connected", "coupled" or "linked" to another component, they may mean that the components are not only directly "connected", "coupled" or "linked", but also indirectly "connected", "coupled" or "linked" through a third component.

[0025] Figure 1 is a block diagram showing a fuel cell system according to an exemplary embodiment of the present invention, and Figure 2 is a flowchart illustrating a method for controlling a fuel cell system according to an exemplary embodiment of the present invention.

[0026] The fuel cell system according to this exemplary embodiment may include a fuel cell stack 10, an air conditioner 20, a hydrogen regulator 30, an air flow acquisition device 40, and a controller 50. The controller 50 may include a processor 51 and a memory 52. ​​The fuel cell stack 10 generates electricity and water through an electrochemical reaction of hydrogen and air. In addition, the fuel cell stack 10 includes a plurality of stacked fuel cells, each of which may include an electrolyte membrane and a pair of electrodes (e.g., a cathode (or air electrode) and an anode (or fuel electrode)) disposed on opposite sides of the electrolyte membrane. The fuel cell stack 10 generates electricity through an electrochemical reaction of hydrogen and oxygen.

[0027] When the fuel cell system is operating, air including oxygen may be supplied to the cathode of the fuel cell stack 10, and hydrogen may be supplied to the anode of the fuel cell stack 10. At this time, the air and hydrogen may be heated to a high temperature suitable for the reaction and then supplied to the fuel cell stack 10. In addition, the fuel cell stack 10 needs to be maintained at a predetermined humidity or higher for chemical reaction. Therefore, the air may be humidified and then supplied to the fuel cell stack 10.

[0028] The air regulator 20 may be configured to regulate the air supplied to the cathode. In particular, the air regulator 20 may be configured to receive compressed air from an air supply device (not shown) and supply the compressed air to the fuel cell stack 10. The air regulator 20 may also be configured to regulate the air released from the fuel cell stack 10. The air regulator 20 may include one or more valves. In an exemplary embodiment, the air regulator 20 may include an air pressure valve and an air shutoff valve.

[0029] In particular, the air shutoff valve may be configured to open or shut off (e.g., block) an air flow passage. The air shutoff valve may be implemented as an airtight flip-type valve. However, the present invention is not limited thereto, and various types of valves may be used as the air shutoff valve. The air pressure valve may be configured to adjust the pressure of the air supplied to the fuel cell stack 10 or to adjust the pressure of the air released from the fuel cell stack 10. Various types of valves known in the prior art may be used as the air pressure valve.

[0030] In addition, the hydrogen regulator 30 may be configured to regulate the hydrogen supplied to the anode. The hydrogen regulator 30 may be configured to receive hydrogen from a hydrogen supply device (not shown) and supply the hydrogen to the fuel cell stack 10. In addition, the hydrogen regulator 30 may be configured to regulate the hydrogen released from the fuel cell stack 10 and may include one or more valves. In an exemplary embodiment, the hydrogen regulator 30 may include a hydrogen pressure valve and a hydrogen shut-off valve.

[0031] In particular, the hydrogen shut-off valve may be configured to open or shut off (e.g., block) a hydrogen flow passage. The hydrogen shut-off valve may be implemented as an airtight flip-top valve. However, the present invention is not limited thereto, and various types of valves may be used as the hydrogen shut-off valve. The hydrogen pressure valve may be configured to adjust the pressure of the hydrogen supplied to the fuel cell stack 10 or to adjust the pressure of the hydrogen released from the fuel cell stack 10. Various types of valves known in the prior art may be used as the hydrogen pressure valve.

[0032] The air flow acquisition device 40 may be configured to obtain the flow rate of the air supplied to the cathode. For example, the air flow acquisition device 40 may include a flow meter configured to measure the flow rate of the fluid flowing through the flow channel per unit time. The air flow acquisition device 40 may be installed in the flow channel connecting the air conditioner 20 and the fuel cell stack 10, and may be configured to obtain the flow rate of the air supplied to the fuel cell stack 10.

[0033] In addition, the controller 50 may be configured to perform the overall configuration of the fuel cell system. The controller 50 may be implemented with one or more controllers. The controller 50 may be configured to obtain information or signals related to the fuel cell system from components of the fuel cell system. The controller 50 may include a processor 51 and a memory 52. ​​The memory 52 may be configured to store instructions, and the processor 51 may be configured to execute instructions to perform the process described below. The controller 50 may be integrated with a controller included in another device other than the fuel cell system of the vehicle.

[0034] The controller 50 can be implemented as a non-volatile computer readable medium including executable program commands. Therefore, the controller 50 can be specifically programmed to execute program commands. Examples of computer readable media can include, but are not limited to, read-only memory (ROM), random access memory (RAM), compact disk (CD)-ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage device. The controller 50 can be implemented with at least one of an application specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, a microcontroller, a microprocessor, and an electrical unit for performing other functions.

[0035] Figure 3 It is shown Figure 2 of step S400, and Figure 4A , Figure 4B , Figure 5A and Figure 5B is a diagram illustrating the operation of a method for controlling a fuel cell system according to an exemplary embodiment of the present invention. Figure 2A method for controlling a fuel cell system according to an exemplary embodiment of the present invention is described.

[0036] When a signal for starting the fuel cell stack 10 is obtained, the controller 50 may be configured to operate the air regulator 20 so that air is supplied to the cathode and air is prevented from being released from the cathode, and may be configured to operate the hydrogen regulator 30 so that hydrogen is supplied to the anode and hydrogen is prevented from being released from the anode (step S100). In order to supply air to the cathode, the controller 50 may be configured to open the air shutoff valve to generate an air flow by the pressure inside the cathode. In order to prevent air or hydrogen from being released, the controller 50 may be configured to block the air passage.

[0037] Figure 4A and Figure 4B A graph depicting the pressure inside the cathode when the fuel cell stack 10 is in a good sealing state (eg, the seal is sufficient to prevent leakage) and when it is in a poor sealing state (eg, insufficient, leakage occurs) is shown. Figure 4A , when the fuel cell stack 10 is in a well-sealed state, the pressure inside the cathode is maintained below the atmospheric pressure after the fuel cell stack 10 stops working and a predetermined period of time has passed. Therefore, even if the air compressor does not work, when the air shutoff valve is opened, air can be supplied to the cathode by the negative pressure formed inside the cathode. Figure 4B When the fuel cell stack 10 is in a poorly sealed state, the pressure inside the cathode is almost the same as the atmospheric pressure after the fuel cell stack 10 stops working and a predetermined period of time has passed. Therefore, when the air shutoff valve is open and the air compressor is not working, air may not be supplied to the cathode.

[0038] The controller 50 may be configured to determine whether an entry condition of a logic for determining a sealing state of the fuel cell stack 10 is satisfied (step S200). In an exemplary embodiment, the controller 50 may be configured to perform step S200 before or simultaneously with step S100. In addition, when the hydrogen pressure inside the anode is not within a preset range, the controller 50 may be configured to determine that an entry condition of the sealing state determination logic is satisfied.

[0039] For example, when the absolute value of the hydrogen pressure inside the anode detected by the hydrogen pressure sensor is less than a preset value, the controller 50 may be configured to determine that the entry condition of the sealing state determination logic is satisfied. When the hydrogen pressure inside the anode detected by the hydrogen pressure sensor is less than -P1 (P1 is greater than zero) or greater than P2 (P2 is greater than zero), the controller 50 may be configured to determine that the entry condition of the sealing state determination logic is satisfied.

[0040] In addition, the controller 50 may be configured to obtain the air flow rate using the air flow acquisition device 40 immediately after the air conditioner 20 is turned on so that air is supplied to the cathode. When the obtained air flow rate is zero, the controller 50 may be configured to determine that the entry condition of the sealing state determination logic is satisfied. Alternatively, when the obtained air flow rate is less than a preset value, the controller 50 may be configured to determine that the entry condition of the sealing state determination logic is satisfied.

[0041] In an exemplary embodiment, the controller 50 may be configured to determine whether the entry condition of the sealing state determination logic is satisfied based on a result obtained by determining whether the time elapsed from when the fuel cell stack 10 just stopped operating is greater than or equal to a preset time. For example, when the time elapsed from when the fuel cell stack 10 just stopped operating is less than a preset time (e.g., about one hour), the controller 50 may be configured to determine that the entry condition of the sealing state determination logic is not satisfied and the fuel cell stack 10 is normal (e.g., no error or failure is detected).

[0042] When the predetermined period of time has not passed since the fuel cell stack 10 stopped working, the pressure inside the fuel cell stack 10 will not be significantly reduced even if the fuel cell stack 10 is in a normal sealed state. In other words, when the predetermined period of time has not passed since the fuel cell stack 10 stopped working, the air flow rate when the air conditioner 20 is turned on may be close to zero even if the fuel cell stack 10 is in a normal sealed state. Therefore, since it is meaningless to determine the sealing state of the fuel cell stack 10 using the air flow rate in a state where the predetermined period of time has not passed since the fuel cell stack 10 stopped working, the fuel cell stack 10 can be allowed to operate normally.

[0043] In addition, the controller 50 may be configured to obtain the flow rate of air supplied to the cathode using the air flow acquisition device 40 immediately after the air regulator 20 is turned on so that air is supplied to the cathode (step S300). In an exemplary embodiment, the controller 50 may be configured to operate the air flow acquisition device 40 to obtain the flow rate of air within a preset time period at preset unit time intervals immediately after the air regulator 20 is turned on so that air is supplied to the cathode. Then, the controller 50 may be configured to determine the sealing state of the fuel cell stack 10 based on the obtained air flow rate (step S400). For example, when the fuel cell stack 10 is in a poor sealing state, the seal between the fuel cells constituting the fuel cell stack 10 may be defective, or the air shut-off valve may be in a poor sealing state.

[0044] Reference Figure 4A, when the fuel cell stack 10 is in a well-sealed state, the pressure inside the cathode decreases, converges to a predetermined value, and remains at the convergent pressure over time after the fuel cell stack 10 stops working. In particular, when the fuel cell stack 10 stops working, air or hydrogen is not allowed to be supplied to the fuel cell stack 10 and released from the fuel cell stack 10. Hydrogen, oxygen, nitrogen, etc. remaining inside the fuel cell stack 10 move from the cathode to the anode or vice versa through the electrolyte membrane, water is generated by the reaction of hydrogen and oxygen, and the number of moles existing in the gaseous state inside the fuel cell stack 10 is reduced. Therefore, after the fuel cell stack 10 stops, as time passes, the pressure inside the anode and the pressure inside the cathode decrease and converge to a predetermined pressure less than atmospheric pressure. At this time, the pressure inside the anode and the pressure inside the cathode converge almost identically.

[0045] At the same time, refer to Figure 4B , when the fuel cell stack 10 is in a poor sealing state, the pressure inside the cathode temporarily decreases, and then returns to atmospheric pressure after the fuel cell stack 10 stops working. When the fuel cell stack 10 is in a poor sealing state, air can be supplied to the cathode or the anode. Therefore, even if the pressure inside the anode or the cathode decreases, ions move through the electrolyte membrane and the pressure can be restored.

[0046] Reference Figure 5A When the fuel cell stack 10 is in a well-sealed state, as described above, the pressure inside the cathode can be maintained at a predetermined pressure lower than the atmospheric pressure, and when the air conditioner 20 is turned on in this state, air can be supplied to the cathode by the pressure difference. Figure 5B , when the fuel cell stack 10 is in a poorly sealed state, as described above, the pressure inside the cathode is almost the same as the atmospheric pressure, and even if the air conditioner 20 is turned on in this state, air flow due to the pressure difference does not occur.

[0047] In an exemplary embodiment, the controller 50 may be configured to determine the sealing state of the fuel cell stack 10 based on a peak air flow value. The peak air flow value may be defined as the highest value of the air flow values ​​obtained at every preset unit time interval. In addition, the controller 50 may be configured to determine the sealing state of the fuel cell stack 10 based on an absolute value of the air flow.

[0048] In response to determining that the fuel cell stack 10 is in a normal (or good) sealing state, the controller 50 may be configured to operate the air regulator 20 and the hydrogen regulator 30 so that air and hydrogen are released from the cathode and the anode, respectively (step S500). In response to determining that the fuel cell stack 10 is in a normal sealing state, the controller 50 may be configured to operate the air regulator 20 and the hydrogen regulator 30 to supply hydrogen and air to the fuel cell stack 10, release hydrogen and air from the fuel cell stack 10, and operate the fuel cell stack 10 normally.

[0049] At the same time, in response to determining that the fuel cell stack 10 is in an abnormal (or poor) sealing state, the controller 50 may be configured to operate the hydrogen regulator 30 that regulates the hydrogen supplied to the anode to increase the amount of hydrogen supplied to the anode. In an exemplary embodiment, the controller 50 may be configured to set the target hydrogen pressure to be greater than a preset hydrogen pressure, and may be configured to operate the hydrogen regulator 30 based on the target hydrogen pressure. The target hydrogen pressure may be a target value for the hydrogen pressure inside the anode, and may be a preset value. Alternatively, the target hydrogen pressure may be a target value for the supply pressure of the hydrogen supplied to the anode, and may be a preset value.

[0050] In addition, in order to increase the amount of hydrogen supplied to the anode, the controller 50 may be configured to operate an air compressor (not shown) to increase the pressure of the hydrogen supplied to the anode. The controller 50 may be configured to set the target hydrogen pressure to be greater than a preset hydrogen pressure, and may be configured to operate the air compressor to adjust the hydrogen supplied to the anode to reach the target hydrogen pressure. In an exemplary embodiment, the controller 50 may be configured to set the target purge frequency to be greater than a preset number of times, and may be configured to operate the hydrogen regulator 30 to perform purges as many times as the target purge frequency. The target purge frequency may be the number of times the purge is performed when the fuel cell stack 10 is initially started, and may be a preset value.

[0051] In the following, reference will be made to Figure 3 Step S400 of the method for controlling a fuel cell system according to an exemplary embodiment of the present invention is described in more detail. The controller 50 may be configured to determine whether the absolute value of the peak air flow value is greater than A (step S410). A is a preset value greater than zero. In response to determining that the absolute value of the peak air flow value is greater than A, the controller 50 may be configured to maintain a target hydrogen pressure and a target purge frequency (step S411).

[0052] In response to determining that the absolute value of the peak air flow value is less than A, the controller 50 may be configured to determine whether the absolute value of the peak air flow value is greater than B (step S420). B is a preset value between 0 and A. In response to determining that the absolute value of the peak air flow value is greater than B, the controller 50 may be configured to increase the target hydrogen pressure and maintain the target purge frequency (step S422). In addition, in response to determining that the absolute value of the peak air flow value is less than B, the controller 50 may be configured to increase the target hydrogen pressure and the target purge frequency (step S421). The target hydrogen pressure or the target purge frequency may be increased to increase the absolute amount of hydrogen supplied to the anode. An exemplary value of A may be 50 kg / hr, and an exemplary value of B may be 5 kg / hr. However, the values ​​of A and B are not limited to the above example values.

[0053] In addition, when the fuel cell stack 10 is in a poorly sealed state, a large amount of air exists inside the cathode and the anode. When a large amount of hydrogen is supplied to the anode in this state, an excessively high voltage may be generated in the fuel cell stack 10 by the electrochemical reaction of air and hydrogen (see Figure 5B ). In addition, when a large amount of hydrogen is supplied to the anode in a state where a large amount of air is present in the cathode, a high voltage may be generated in the fuel cell stack 10. When a large amount of hydrogen is supplied to the anode in a state where a large amount of air is present in the anode, a high reverse voltage may be generated in the fuel cell stack 10.

[0054] An excessively high voltage may damage the fuel cell stack 10. In particular, when the high voltage lasts for a predetermined period of time or longer, the fuel cell stack 10 may be seriously damaged. Therefore, it is desirable to prevent the generation of high voltage. In particular, even if a high voltage is generated, the time for which the high voltage is maintained should be reduced.

[0055] According to the present invention, the fuel cell system can increase the target hydrogen pressure or the target purge frequency to increase the absolute amount of hydrogen supplied to the anode, so that the air and hydrogen remaining in the fuel cell stack 10 react with each other in a short period of time, thereby reducing the time for which the high voltage is maintained. Therefore, the possibility of damaging the fuel cell stack 10 can be reduced.

[0056] In an exemplary embodiment, when the fuel cell stack 10 is in a poor sealing state, the controller 50 may be configured to perform safety control to temporarily connect a resistor to the fuel cell stack 10. When the fuel cell stack 10 is normally started, the controller 50 may be configured to disconnect the resistor from the fuel cell stack 10, and when an excessively high voltage is generated when the fuel cell stack 10 is started, the controller 50 may be configured to connect the resistor to the fuel cell stack 10 so that the voltage of the fuel cell stack 10 is applied to the resistor.

[0057] Reference Figure 5BBy performing safety control, the voltage of the fuel cell stack 10 can be quickly reduced. In an exemplary embodiment, before the voltage of the fuel cell stack 10 increases significantly, the controller 50 can be configured to perform safety control based on the air flow rate to temporarily connect the resistor to the fuel cell stack 10. Therefore, before the voltage of the fuel cell stack 10 increases significantly, the possibility of damage to the fuel cell stack 10 can be reduced by performing safety control based on the air flow rate.

[0058] The present invention described above can be implemented as a computer-readable code in a non-transitory computer-readable recording medium. A non-transitory computer-readable recording medium may include all types of storage devices for storing data that can be read by a computer system. Examples of non-transitory computer-readable recording media may include a hard disk drive (HDD), a solid state drive (SSD), a silicon disk drive (SDD), a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like. A non-transitory computer-readable recording medium may be implemented in the form of a carrier wave (e.g., transmitted via the Internet). In addition, a computer may include a processor or a controller.

[0059] Therefore, the above exemplary embodiments are interpreted as illustrative and not restrictive in all aspects. The scope of the present invention should be determined by the attached claims and their legal equivalents, rather than by the above description, and all changes falling within the meaning and equivalent scope of the attached claims are intended to be included therein. According to the exemplary embodiments of the present invention, at least the following effects are achieved.

[0060] First, when the fuel cell stack starts operating, the fuel cell system can determine the sealing state of the fuel cell stack based on the air flow rate obtained immediately after the air conditioner is turned on, thereby directly detecting the sealing performance of the fuel cell stack when the fuel cell system starts operating.

[0061] Second, the fuel cell system can effectively detect the sealing performance of the fuel cell stack to prevent excessive voltage from being generated in the fuel cell stack or, even if high voltage is generated, reduce the time the high voltage is maintained, thereby preventing damage to the fuel cell system.

[0062] The effects of the present invention are not limited to the above effects, and any other effects not mentioned herein will be clearly understood by those skilled in the art from the attached claims. In the above, although the present invention has been described with reference to the exemplary embodiments and the accompanying drawings, the present invention is not limited thereto, but various modifications and changes may be made by those skilled in the art without departing from the spirit and scope of the present invention as claimed in the attached claims.

Claims

1. A method for controlling a fuel cell system, comprising the following steps: When the fuel cell stack is started, after an air conditioner configured to regulate air supplied to the cathode is turned on, a flow rate of air supplied to the cathode is obtained by a controller; and Based on the obtained air flow rate, the sealing state of the fuel cell stack is determined by the controller, When the air flow rate is greater than or equal to a preset threshold, the fuel cell stack is determined to be in a normal sealing state, and when the air flow rate is less than the preset threshold, the fuel cell stack is determined to be in an abnormal sealing state.

2. The method of claim 1, wherein: The sealing state of the fuel cell stack is determined based on a peak flow rate of air supplied to the cathode after the air conditioner is turned on.

3. The method of claim 1, wherein: The sealing state of the fuel cell stack is determined based on an absolute value of a flow rate of air supplied into the cathode after the air conditioner is turned on.

4. The method of claim 1, further comprising: before obtaining the flow rate of air supplied into the cathode, operating the air conditioner by the controller so that air is supplied into the cathode and air is prevented from being released from the cathode; and When a signal for starting the fuel cell stack is obtained, a hydrogen regulator is operated by the controller to allow hydrogen to be supplied into an anode and to prevent hydrogen from being released from the anode.

5. The method of claim 4, further comprising: After determining the sealing state of the fuel cell stack, operating the air conditioner by the controller to release air from the cathode; and In response to determining that the fuel cell stack is in a normally sealed state, the hydrogen regulator is operated by the controller to release hydrogen from the anode.

6. The method of claim 1, further comprising: After determining the sealing state of the fuel cell stack, in response to determining that the fuel cell stack is in an abnormal sealing state, operating a hydrogen regulator by the controller to increase the amount of hydrogen supplied to the anode, The hydrogen regulator is configured to regulate the hydrogen supplied to the anode.

7. The method of claim 6, wherein: In the operation of the hydrogen regulator, a target hydrogen pressure is set to be greater than a preset hydrogen pressure, and the hydrogen regulator is operated to regulate the hydrogen supplied to the anode to reach the target hydrogen pressure.

8. The method of claim 6, wherein: In the operation of the hydrogen regulator, in response to determining that the fuel cell stack is in a normal sealing state, the hydrogen regulator is operated to perform a preset number of purges, and in response to determining that the fuel cell stack is in an abnormal sealing state, the hydrogen regulator is operated to perform a target number of purges set to be greater than the preset number, wherein the purge is defined as supplying hydrogen into the anode at an increased pressure within a preset time period.

9. The method of claim 1, further comprising: In response to determining that the fuel cell stack is in an abnormally sealed state, a safety control is performed by the controller to temporarily connect a resistor to the fuel cell stack to reduce a high potential generated in the fuel cell stack.

10. A fuel cell system comprising: at least one processor; an air flow acquisition device connected to the at least one processor and configured to obtain the flow rate of air supplied to the cathode; as well as a memory connected to the at least one processor and configured to store a plurality of instructions, Wherein, the instructions, when executed, cause the processor to: When the fuel cell stack is started, after turning on an air conditioner configured to regulate air supplied to the cathode, operating the air flow acquisition device to obtain a flow rate of air supplied to the cathode; and determining a sealing state of the fuel cell stack based on the obtained air flow rate, When the air flow rate is greater than or equal to a preset threshold, the fuel cell stack is determined to be in a normal sealing state, and when the air flow rate is less than the preset threshold, the fuel cell stack is determined to be in an abnormal sealing state.

11. The system of claim 10, wherein: The sealing state of the fuel cell stack is determined based on a peak flow rate of air supplied to the cathode after the air conditioner is turned on.

12. The system of claim 10, wherein: The sealing state of the fuel cell stack is determined based on an absolute value of a flow rate of air supplied into the cathode after the air conditioner is turned on.

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