Cold start control method of fuel cell stack and cold start system of fuel cell stack

Abstract

A cold start control method of a fuel cell stack and a system thereof may include determining, by a controller, whether a cold start is needed, opening, by the controller, an air shut-off valve when the cold start is needed, determining, by the controller, whether an output voltage of the fuel cell stack is restored, and opening, by the controller, an air shut-off valve when the output voltage of the fuel cell stack is restored. The cold start completion standard of the fuel cell stack is satisfied by controlling the opening amount of the air stop valve.

Description

Technical Field

[0001] The present disclosure relates to a cold start control method for a fuel cell stack and a cold start system for a fuel cell stack. Background Art

[0002] A fuel cell is a device that receives hydrogen and air from the outside and generates electric power through an electrochemical reaction inside the fuel cell stack. The fuel cell can be used as a power source in various fields, such as a fuel cell electric vehicle (FCEV) and a fuel cell for power generation.

[0003] The fuel cell stack built in a fuel cell vehicle is sensitive to the outside air temperature, and particularly the power generation efficiency is significantly reduced at low temperatures. In addition, water produced by the reaction of hydrogen and oxygen in the fuel cell stack freezes, adversely affecting the durability of the fuel cell stack.

[0004] Therefore, in a case where the outside air temperature is low, the fuel cell vehicle performs a low-temperature start (cold start). The cold start uses loads within the fuel cell system, such as a heating element (COD), an air compressor (ACP), and a high-voltage battery, to raise the temperature of the fuel cell stack, and causes the fuel cell stack and the loads to generate heat to achieve a stable temperature rise.

[0005] Conventionally, the cold start of the fuel cell stack is performed by opening all air shut-off valves (ACP) of the air supply system during the cold start. This causes cold air from the outside air to continuously flow into the fuel cell stack, causing the water produced inside the fuel cell stack to quickly freeze. As a result, there is a problem in that the reaction area where hydrogen and oxygen react inside the fuel cell stack is reduced, and thus it takes a long time to reach the cold start completion condition, or even cold start failure may often occur.

[0006] The information disclosed in this background art section is only for enhancing the understanding of the general background of the present disclosure, and should not be regarded as an admission that this information forms the prior art that is already known, available, or being used. Summary of the Invention

[0007] The present disclosure relates to a cold start control method for a fuel cell stack and a cold start system for a fuel cell stack.

[0008] Some embodiments of the present disclosure can solve the above problems by providing a cold start control method for a fuel cell stack that can stably perform the cold start of the fuel cell stack.

[0009] The cold start control method of a fuel cell stack according to an embodiment of the present disclosure may include: determining by a controller whether cold start is required; when cold start is required, opening an air shut-off valve by the controller; determining by the controller whether the output voltage of the fuel cell stack is restored; and when the output voltage of the fuel cell stack is restored, meeting the cold start completion criteria of the fuel cell stack by controlling the opening amount of the air shut-off valve.

[0010] When determining whether cold start is required, it may be determined whether cold start is required based on one or more of an external air temperature and a coolant temperature.

[0011] When opening the air shut-off valve, the air shut-off valve may be opened to the maximum.

[0012] When determining whether the output voltage is restored, it may be determined whether the output voltage is restored based on whether the output voltage of the fuel cell stack is maintained at or greater than a reference voltage and for a reference time or longer.

[0013] Meeting the cold start completion criteria of the fuel cell stack by controlling the opening amount of the air shut-off valve may include: monitoring by the controller one or more of the output voltage, output current, cell voltage deviation, coolant temperature, and air outlet temperature of the fuel cell stack; increasing the heat generation amount of the fuel cell stack by reducing the opening amount of the air shut-off valve; and preventing the shutdown of the fuel cell stack by increasing the opening amount of the air shut-off valve.

[0014] When increasing the heat generation amount of the fuel cell stack, the driving speed of the air compressor may be controlled to be constant, and the opening amount of the air shut-off valve may be reduced at a constant angular velocity.

[0015] When preventing the shutdown of the fuel cell stack, the driving speed of the air compressor may be controlled to be constant, and the opening amount of the air shut-off valve may be increased at a constant angular velocity.

[0016] The driving speed of the air compressor may be maintained the same as in the step of increasing the heat generation amount of the fuel cell stack, and the opening speed of the air shut-off valve may be faster than the closing speed.

[0017] When meeting the cold start completion criteria of the fuel cell stack by controlling the opening amount of the air shut-off valve, increasing the heat generation amount of the fuel cell stack and preventing the shutdown of the fuel cell stack may be repeatedly executed, and cold start of the fuel cell stack may be performed.

[0018] When the output voltage of the fuel cell stack is maintained at a first voltage or lower for a first time or longer, or when the cell voltage deviation of the fuel cell stack is maintained at a first voltage deviation or greater or more for a first time or longer, preventing the shutdown of the fuel cell stack may be performed.

[0019] When the output voltage of the fuel cell stack is maintained at a second voltage or greater for a second time or a longer time, or when the cell voltage deviation of the fuel cell stack is maintained at a second voltage deviation or lower for a second time or a longer time, an increase in the heat generation amount of the fuel cell stack may be performed.

[0020] The controller may monitor one or more of the output voltage, output current, cell voltage deviation, coolant temperature, and air outlet temperature of the fuel cell stack, and terminate cold start when the cold start completion criterion is satisfied.

[0021] The cold start system of a fuel cell stack according to an embodiment of the present disclosure may include an air supply system including: an air compressor and an air shut-off valve; and a controller that determines whether cold start is required, opens the air shut-off valve when cold start is required, determines whether the output voltage of the fuel cell stack is restored, and satisfies the cold start completion criterion of the fuel cell stack by controlling the opening amount of the air shut-off valve when the output voltage of the fuel cell stack is restored.

[0022] The controller may monitor one or more of the output voltage, output current, cell voltage deviation, coolant temperature, and air outlet temperature of the fuel cell stack, increase the heat generation amount of the fuel cell stack by closing the air shut-off valve according to the monitoring result, or prevent the fuel cell stack from shutting down by opening the air shut-off valve, and terminate the cold start of the fuel cell stack according to the monitoring result.

[0023] The cold start control method of a fuel cell stack according to an embodiment of the present disclosure has the advantage of being able to stably perform cold start of the fuel cell stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figures 1 to 3 It is a flowchart of a cold start control method of a fuel cell stack according to an embodiment of the present disclosure.

[0025] Figure 4 and Figure 5 is a configuration diagram for explaining the cold start system of a fuel cell stack according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0026] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the drawings. The same or similar components may be given the same reference numerals, and redundant descriptions thereof may be omitted.

[0027] In the following description, if the detailed description of the known technology associated with the exemplary embodiments of the present disclosure may unnecessarily obscure the gist of the embodiments, the detailed description thereof may be omitted. In addition, the accompanying drawings are provided for easy understanding of the exemplary embodiments of the present disclosure and do not necessarily limit the technical spirit of the present disclosure, and potential embodiments may be understood to include all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.

[0028] Although terms such as "first", "second", etc. may be used to describe various components, such components are not necessarily limited by such terms. Such terms are only used to distinguish one component from another.

[0029] Unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms.

[0030] In the specification, it should also be understood that the term "comprise / include" stipulates the presence of the stated features, integers, steps, operations, elements, components, and / or combinations thereof, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations.

[0031] The controller may include a communication device configured to communicate with other controllers or sensors, a memory (storage medium) configured to store instructions, an operating system, logical commands, input and output information, etc., and at least one processor configured to execute control to perform determinations, calculations, judgments, etc. necessary for controlling the functions assigned to the controller.

[0032] Figures 1 to 3 It is a flowchart of a cold start control method for a fuel cell stack according to an embodiment of the present disclosure. Figure 4 and Figure 5 is a configuration diagram for explaining a cold start system of a fuel cell stack according to an embodiment of the present disclosure.

[0033] Referring to Figures 1 to 5 , exemplary embodiments of the present disclosure will be described.

[0034] The cold start control method for a fuel cell stack according to an embodiment of the present disclosure may include the following steps: determining by the controller 400 whether cold start is required (operation S100); when cold start is required, opening the air shut-off valve 200 by the controller 400 (operation S200); determining by the controller 400 whether the output voltage of the fuel cell stack 300 is restored (operation S300); and when the output voltage of the fuel cell stack 300 is restored, satisfying the cold start completion criterion by controlling the opening amount of the air shut-off valve 200 (operation S400).

[0035] In the step (operation S100) of determining whether the fuel cell stack 300 needs a cold start by the controller 400, it can be determined by an external temperature sensor, a coolant temperature sensor, etc. provided in the fuel cell system. For example, when the external air temperature is 4 °C or lower, it can be determined that a cold start is required, or when the coolant temperature is 10 °C or lower, it can be determined that a cold start is required.

[0036] When the controller 400 determines that a cold start is required, the controller 400 can perform the step of opening the air shut-off valve 200 to restore the output voltage of the fuel cell stack 300 (operation S200). The restoration of the output voltage of the fuel cell stack 300 can be that the output voltage of the fuel cell stack can be generated up to a voltage value that can minimally drive various accessories (converters, air compressors, batteries, etc.) constituting the fuel cell system.

[0037] That is, at the start of cold start, due to the chemical reaction in the fuel cell stack 300, the voltage can rise rapidly, but the water produced at the start of startup can freeze quickly, and the frozen produced water reduces the reaction area where oxygen and hydrogen react in the fuel cell stack 300. Therefore, the performance of the fuel cell stack 300 decreases. The air compressor 100 can be driven to inject air into the fuel cell stack 300 so that the output voltage of the fuel cell stack 300 can be restored again, and thus, the output voltage of the fuel cell stack 300 can increase again.

[0038] It is preferable to open the air shut-off valve 200 to the maximum. Due to the maximum opening of the air shut-off valve 200, low-temperature air can continue to flow into the fuel cell stack 300. However, since the reaction between hydrogen and oxygen is crucial for restoring the output voltage of the fuel cell stack 300, it may be useful to restore the output voltage of the fuel cell stack 300 in the shortest possible time.

[0039] After opening the air shut-off valve 200, the controller 400 can monitor the output voltage of the fuel cell stack 300 to determine whether the output voltage is restored. In the step of determining whether the output voltage is restored (operation S300), it can be determined whether the output voltage is restored based on whether the output voltage of the fuel cell stack 300 is maintained at or greater than the reference voltage for the reference time or longer than the reference time.

[0040] For example, the reference voltage can be set between 250 V and 300 V, and the reference voltage can be the voltage that can minimally drive various accessories provided in the fuel cell system.

[0041] When the restoration of the output voltage of the fuel cell stack 300 is completed, the step of controlling the opening amount of the air shut-off valve can be performed to perform a full cold start of the fuel cell stack 300 (operation S400).

[0042] The steps to meet the cold start completion criteria of the fuel cell stack may include the following steps: monitoring, by a controller 400, one or more of the output voltage, output current, cell voltage deviation, coolant temperature, and air outlet temperature of the fuel cell stack 300 (operation S410); increasing the heat generation amount of the fuel cell stack 300 by reducing the opening amount of the air shut-off valve 200 (operation S420); and preventing the shutdown of the fuel cell stack 300 by increasing the opening amount of the air shut-off valve 200 (operation S440).

[0043] To determine whether the cold start of the fuel cell stack 300 is completed, in the steps to meet the cold start completion criteria of the fuel cell stack 300 (operation S400), the controller 400 may continuously monitor one or more of the output voltage, output current, cell voltage deviation, coolant temperature, and air outlet temperature of the fuel cell stack 300. When performing the step of controlling the opening amount of the air flow control valve 200 (operation S400), when the cold start completion criteria are met as a result of the monitoring (operation S500), which will be described later, the cold start may be terminated.

[0044] When the output voltage of the fuel cell stack 300 recovers, the step of increasing the heat generation amount of the fuel cell stack may be first performed (operation S420). To increase the heat generation amount of the fuel cell stack 300, embodiments of the present disclosure may intentionally reduce the opening amount of the air shut-off valve 200 to reduce the flow rate of air flowing into the fuel cell stack 300. As a result, due to the increase in the mass transfer resistance inside the fuel cell stack 300, the increase in the output voltage of the fuel cell stack 300 may be delayed, and the heat generation amount of the fuel cell stack 300 may increase naturally.

[0045] Specifically, in the step of increasing the heat generation amount of the fuel cell stack 300 (operation S420), the controller 400 may control the driving speed of the air compressor 100 and reduce the opening amount of the air shut-off valve 200 at a constant angular velocity. Reducing the opening amount of the air shut-off valve 200 may increase the heat generation amount of the fuel cell stack 300 by increasing the mass transfer resistance.

[0046] Reference Figure 4 and 5 , when excessive low-temperature air is introduced during cold start as shown in Figure 4 , the low-temperature air may inhibit the heat generation of the fuel cell stack 300. In addition, as shown in Figure 5 , if too much low-temperature air is bypassed during cold start and only a small amount of air is supplied to the fuel cell stack 300, then the mass transfer resistance may increase, and the heat generation amount of the fuel cell stack 300 may increase.

[0047] However, maintaining the driving speed of the air compressor 100 at a constant speed can prevent the loss of reaction area due to the freezing of the water produced in the fuel cell stack 300 by reducing the flow rate of the low-temperature air flowing into the fuel cell stack 300 over time.

[0048] Set the driving speed of the air compressor 100 to a driving speed that can continuously generate the output current generated by the fuel cell stack 300 during cold start.

[0049] Specifically, the controller 400 of the fuel cell system can store the data mapping of the flow rate supplied to the fuel cell stack 300 according to the opening amount of the air cutoff valve 200 and the speed of the air compressor 100. The controller 400 can use the data mapping to control the driving speed of the air compressor 100 and the opening amount of the air cutoff valve 200 to meet the required output of the fuel cell stack 300.

[0050] During the cold start of the fuel cell stack 300, most of the output generated by the fuel cell stack 300 can be transmitted to the battery. After the output voltage of the fuel cell stack 300 is restored, the output voltage and output current generated by the fuel cell stack 300 can be applied to the battery. The controller 400 can control the air compressor 100 to be driven at a driving speed that can continuously generate the output current currently output from the fuel cell stack 300, and the controller 400 can control the opening amount of the air cutoff valve 200 to gradually close.

[0051] For example, during the cold start of the fuel cell stack 300, when the output voltage of the fuel cell stack 300 is restored and the output current applied to the battery is 60A, the controller 400 can determine the air flow rate capable of continuously generating 60A output current, and then determine the opening amount of the air cutoff valve 200 and the driving speed of the air compressor 100 to inject the corresponding flow rate into the fuel cell stack 300. The air cutoff valve 200 can be gradually closed, and the driving speed of the air compressor 100 can be maintained constant. Therefore, the driving speed of the air compressor 100 can be preferably determined to be a constant speed from the beginning, such as 60000 rpm or higher.

[0052] For example, the closing angular rate of the air cutoff valve 200 can be determined to be between 0.1 degrees / second and 1.0 degrees / second. In addition, to prevent the air cutoff valve 200 from closing completely, the minimum opening angle of the air cutoff valve 200 can be preferably set to 0.5 degrees to 1.0 degrees.

[0053] Although the heat generation amount of the fuel cell stack 300 can be increased by the above control, if the air shut-off valve 200 remains closed continuously, the voltage increase of the fuel cell stack 300 can be significantly delayed. Alternatively, if the cell voltage deviation of the fuel cell stack 300 exceeds a significant value, the shutdown of the fuel cell stack 300 can be caused. Therefore, the step of increasing the heat generation amount of the fuel cell stack 300 (operation S420) can preferably be performed in the step of preventing the shutdown of the fuel cell stack (operation S440).

[0054] In the step of preventing the shutdown of the fuel cell stack 300 (operation S440), the opening amount of the air shut-off valve 200 can be increased at a constant angular velocity, while the driving speed of the air compressor 100 can be controlled to be constant. In order to prevent the shutdown of the fuel cell stack 300, the air shut-off valve 200 can be gradually opened to supply low-temperature air into the fuel cell stack 300. Therefore, the heat generation of the fuel cell stack 300 can be suppressed by supplying low-temperature air, but the output voltage generated by the fuel cell stack 300 can be increased and the cell voltage deviation can be reduced, resulting in preventing the shutdown of the fuel cell stack 300.

[0055] In the step of preventing the shutdown of the fuel cell stack 300 (operation S440), the driving speed of the air compressor 100 can be maintained the same as that in the step of increasing the heat generation amount of the fuel cell stack 300 (operation S420), but it can be preferable to control the opening speed of the air shut-off valve 200 to be faster than the closing speed.

[0056] When the fuel cell stack 300 shuts down, a cold start must be performed again. Therefore, since the mid-course shutdown of the fuel cell stack 300 can be a critical situation, it can be preferable to quickly open the air shut-off valve 200 to prevent the shutdown of the fuel cell stack 300.

[0057] For example, if the closing angular rate of the air shut-off valve 200 is determined to be between 0.1 degree / second and 1.0 degree / second, then the opening angular rate can be determined to be between 0.2 degree / second and 2.0 degree / second. Additionally, it can be desirable to determine the angular rate to be 1.5 times or greater than the closing angular rate.

[0058] As described above, during the cold start of the fuel cell stack 300, the step of increasing the heat generation amount of the fuel cell stack (operation S420) and the step of preventing the shutdown of the fuel cell stack (operation S440) can be repeatedly performed, so that the fuel cell stack 300 is completed (operation S500) when the cold start completion condition is satisfied.

[0059] Therefore, if specific conditions are met, the step of increasing the heat generation amount of the fuel cell stack 300 (operation S420) can be carried out during the step of preventing the fuel cell stack 300 from shutting down (operation S440). Alternatively, if specific conditions are met, the step of preventing the fuel cell stack 300 from shutting down (operation S440) can be carried out during the step of increasing the heat generation amount of the fuel cell stack 300 (operation S420), so that cold start of the fuel cell stack 300 can be performed.

[0060] Specifically, it can be determined whether the output voltage of the fuel cell stack 300 is maintained at a first voltage or lower for a first time or a longer time than the first time, or whether the battery voltage deviation of the fuel cell stack is maintained at a first voltage deviation or more for a first time or a longer time than the first time (operation S430). If this is satisfied (yes in operation S430), then the step of preventing the fuel cell stack 300 from shutting down (operation S440) can be carried out. The first voltage can refer to a voltage at which accessories of the fuel cell system cannot operate. That is to say, the first voltage can be a voltage of about 270V or lower, which can be lower than the driving voltage.

[0061] The controller 400 can continuously monitor one or more of the output voltage, output current, battery voltage deviation, coolant temperature, and air outlet temperature of the fuel cell stack 300, and determine whether the monitored output voltage or battery voltage deviation of the fuel cell stack 300 is maintained for a certain period or more. If this is satisfied, the process can proceed to the step of preventing the fuel cell stack 300 from shutting down (operation S440).

[0062] Conversely, the controller 400 can determine whether the output voltage of the fuel cell stack 300 is maintained at a second voltage or higher for a second time or a longer time than the second time, or whether the battery voltage deviation of the fuel cell stack 300 is maintained at a second voltage deviation or lower for a second time or a longer time than the second time (operation S450). If this is satisfied, then the step of increasing the heat generation amount of the fuel cell stack can be carried out (operation S420). Here, the second voltage can be a voltage at which it is determined that the fuel cell stack has generated sufficient heat, and can refer to, for example, a voltage of about 300V or higher. Alternatively, the second voltage can refer to a voltage at which sufficient power is generated and sufficient current is output in the fuel cell stack.

[0063] The controller 400 can continuously monitor one or more of the output voltage, output current, battery voltage deviation, coolant temperature, and air outlet temperature of the fuel cell stack 300, and if the monitored output voltage or battery voltage deviation of the fuel cell stack 300 is maintained for a certain period or more, then the process can proceed to the step of increasing the heat generation amount of the fuel cell stack 300 (operation S420).

[0064] The controller 400 may continuously monitor one or more of the output voltage, output current, cell voltage deviation, coolant temperature, and air outlet temperature of the fuel cell stack 300 to increase heat generation (operation S420), and may finally terminate the cold start when the cold start completion criterion is satisfied.

[0065] The cold start system of a fuel cell stack according to an embodiment of the present disclosure may include an air supply system including an air compressor 100 and an air shut-off valve 200; and a controller 400 that determines whether a cold start is required, opens the air shut-off valve 200 when a cold start is required, determines whether the output voltage of the fuel cell stack 300 has recovered, and satisfies the cold start completion criterion of the fuel cell stack by controlling the opening amount of the air shut-off valve 200 when the output voltage of the fuel cell stack 300 has recovered.

[0066] The controller 400 may monitor one or more of the output voltage, output current, cell voltage deviation, coolant temperature, and air outlet temperature of the fuel cell stack 300, increase the heat generation amount of the fuel cell stack 300 by closing the air shut-off valve 200 according to the monitoring result, or prevent the fuel cell stack 300 from shutting down by opening the air shut-off valve 200, and terminate the cold start of the fuel cell stack 300 according to the monitoring result.

[0067] Although the present disclosure has been illustrated and described in connection with specific exemplary embodiments and the accompanying drawings, those skilled in the art can readily understand that various modifications and changes can be made thereto without departing from the spirit and scope of the present disclosure defined by the appended claims.

Claims

1. A cold start control method for a fuel cell stack, the method comprising the following steps: Determine if a cold start is required; In response to a cold start being required, opening the air shutoff valve; determining whether the output voltage of the fuel cell stack is restored; as well as In response to the output voltage of the fuel cell stack being restored, a cold start completion criterion of the fuel cell stack is satisfied by controlling an opening amount of the air shutoff valve.

2. The method according to claim 1, wherein: Whether the cold start is required is determined based on one or both of an air temperature of the outside air and a coolant temperature of the coolant.

3. The method according to claim 1, wherein: The opening of the air shutoff valve includes opening the air shutoff valve to a maximum.

4. The method according to claim 1, wherein: Whether the output voltage of the fuel cell stack is restored is determined based on whether the output voltage is maintained at a reference voltage or greater than a reference voltage and for a reference time or longer than the reference time.

5. The method according to claim 1, wherein: Controlling the opening amount of the air shut-off valve includes: monitoring one or any combination of an output voltage, an output current, a cell voltage deviation, a coolant temperature, and an air outlet temperature of the fuel cell stack; increasing the amount of heat generated by the fuel cell stack by reducing the opening amount of the air shutoff valve; and Shutdown of the fuel cell stack is prevented by increasing the opening amount of the air shutoff valve.

6. The method according to claim 5, wherein: Increasing the heat generation of the fuel cell stack includes: controlling the driving speed of the air compressor to be constant; and reducing the opening amount of the air shutoff valve at a constant angular velocity; Wherein preventing the shutdown of the fuel cell stack comprises: controlling the driving speed of the air compressor to be constant; and The opening amount of the air shutoff valve is increased at a constant angular velocity.

7. The method according to claim 6, wherein: The driving speed of the air compressor is equal to the driving speed of the air compressor when the heat generation amount of the fuel cell stack is increased, and wherein the constant angular velocity of the opening amount of the air shutoff valve is faster than the closing angular velocity thereof.

8. The method according to claim 5, wherein: When the cold start completion standard of the fuel cell stack is met by controlling the opening amount of the air shutoff valve, the steps of increasing the heat generation of the fuel cell stack and preventing the shutdown of the fuel cell stack are repeated, and the cold start of the fuel cell stack is performed.

9. The method according to claim 8, wherein: In response to an output voltage of the fuel cell stack being maintained at a first voltage or lower for a first time or longer than the first time, or in response to a cell voltage deviation of the fuel cell stack being maintained at a first voltage deviation or greater for a first time or longer than the first time, performing a step of preventing shutdown of the fuel cell stack; as well as Wherein, in response to the output voltage of the fuel cell stack being maintained at a second voltage or greater for a second time or longer than the second time, or in response to the cell voltage deviation of the fuel cell stack being maintained at a second voltage deviation or lower for a second time or longer than the second time, a step of increasing the heat generation of the fuel cell stack is performed.

10. The method according to claim 1, further comprising the steps of: monitoring one or any combination of an output voltage, an output current, a cell voltage deviation, a coolant temperature, and an air outlet temperature of the fuel cell stack; and In response to the cold start completion criteria being met, the cold start is terminated.

11. A cold start system for a fuel cell stack, the system comprising: An air supply system, the air supply system comprising an air compressor and an air shut-off valve; one or more controllers; as well as A storage medium storing computer-readable instructions that, when executed by the one or more controllers, enable the one or more controllers to: Determine if a cold start is required; In response to requiring the cold start, opening the air shutoff valve; determining whether the output voltage of the fuel cell stack is restored; and In response to the output voltage of the fuel cell stack being restored, a cold start completion criterion of the fuel cell stack is satisfied by controlling an opening amount of the air shutoff valve.

12. The system of claim 11, wherein the instructions enable the one or more controllers to determine whether the cold start is required based on one or both of an outside air temperature and a coolant temperature.

13. The system according to claim 11, wherein: The instructions further enable the one or more controllers to open the air shutoff valve to a maximum when the cold start is required.

14. The system according to claim 11, wherein: The instructions enable the one or more controllers to determine whether the output voltage of the fuel cell stack is recovered based on whether the output voltage of the fuel cell stack is maintained at or above a reference voltage for a reference time or longer than the reference time.

15. The cold start system according to claim 11, wherein: The instructions further enable the one or more controllers to: monitoring one or any combination of an output voltage, an output current, a cell voltage deviation, a coolant temperature, and an air outlet temperature of the fuel cell stack; increasing the amount of heat generated by the fuel cell stack by closing the air shutoff valve according to the monitoring result, or preventing shutdown of the fuel cell stack by opening the air shutoff valve, and The cold start of the fuel cell stack is terminated according to the monitoring result.

16. The system according to claim 11, wherein: The instructions enable the one or more controllers to: constantly control the driving speed of the air compressor and increase the amount of heat generated by the fuel cell by reducing the opening amount of the air shutoff valve at a constant angular velocity; and The instructions enable the one or more controllers to constantly control the driving speed of the air compressor and prevent the fuel cell stack from being shut down by increasing the opening amount of the air shutoff valve at a constant angular velocity.

17. The system of claim 16, wherein: The driving speed of the air compressor is equal to the driving speed of the air compressor when the heat generation amount of the fuel cell stack is increased, and wherein the constant angular velocity of the opening amount of the air shutoff valve is faster than the closing angular velocity thereof.

18. The system of claim 11, wherein: The instructions enable the one or more controllers to perform a cold start of the fuel cell stack by repeatedly increasing heat generation of the fuel cell stack and preventing shutdown of the fuel cell stack.

19. The system of claim 18, wherein: The instructions enable the one or more controllers to: prevent shutdown of the fuel cell stack in response to an output voltage of the fuel cell stack being maintained at a first voltage or less for a first time or longer than a first time, or in response to a cell voltage deviation of the fuel cell stack being maintained at a first voltage deviation or greater for a first time or longer than a first time; as well as In which, the instructions enable the one or more controllers to: increase the heat generation of the fuel cell stack in response to the output voltage of the fuel cell stack being maintained at a second voltage or greater for a second time or longer than the second time, or in response to the cell voltage deviation of the fuel cell stack being maintained at a second voltage deviation or lower for a second time or longer than the second time.

20. The system of claim 11, wherein: The instructions enable the one or more controllers to: monitor one or any combination of output voltage, output current, cell voltage deviation, coolant temperature, and air outlet temperature of the fuel cell stack; and terminate the cold start in response to meeting cold start completion criteria.

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