Fuel cell control method and corresponding device

Abstract

The invention relates to a fuel cell control method and a corresponding device, and the method comprises the steps: when the temperature of the environment where a fuel cell is located is smaller than a preset temperature threshold value, the stack temperature of the fuel cell is determined, and the stack temperature is the inlet temperature of a cooling liquid entering the stack and the outlet temperature of the cooling liquid exiting the stack in the fuel cell; determining a target flow according to the stack temperature; and controlling a preset gas to purge moisture stored in the electric pile at a target flow rate, obtaining a purge time length, and controlling the operation state of the fuel cell according to the purge time length. According to the pile temperature, the target flow is determined, so that the situation that the pile is purged by too large flow and too small flow can be avoided. According to the technical scheme, the preset gas with the target flow is used for purging the moisture generated in the electric pile, and the running state of the fuel cell is controlled according to the purging duration, so that the conditions of excessive whistling and invalid purging can be reduced, meanwhile, the damage to a fuel cell engine can be reduced, and the service life of the fuel cell can be prolonged.

Description

Technical Field

[0001] The present disclosure relates to the field of battery technology, and in particular, to a control method and a corresponding device for a fuel cell. Background Art

[0002] Fuel cells are devices that generate water by reacting oxygen and hydrogen and discharge electricity at the same time. When a fuel cell discharges electricity, a large amount of water will be generated inside the fuel cell stack. If the water in the fuel cell stack is not removed in time, it will have an impact on the fuel cell stack.

[0003] In the related art, the fuel cell stack is purged by blowing air into the interior of the fuel cell stack so that the air can carry out the moisture in the fuel cell stack. However, when the moisture stored in the fuel cell stack is purged by this method, excessive purging or ineffective purging may occur. Summary of the invention

[0004] The purpose of the present disclosure is to provide a control method and a corresponding device for a fuel cell to solve the technical problems existing in the related art.

[0005] In order to achieve the above objectives, in a first aspect, the present disclosure provides a control method for a fuel cell, comprising: When the ambient temperature of the fuel cell is less than a preset temperature threshold, the stack temperature of the fuel cell is determined, wherein the stack temperature is the inlet temperature of the coolant entering the stack and the outlet temperature of the coolant exiting the stack in the fuel cell, and the preset temperature threshold is the maximum ambient temperature value of the fuel cell when cold shutdown occurs; Determining a target flow rate according to the stack temperature; The preset gas is controlled to purge the moisture stored in the fuel cell stack at the target flow rate, and the purge duration is obtained at the same time. The operating state of the fuel cell is controlled according to the purge duration.

[0006] Optionally, controlling the operating state of the fuel cell according to the purge duration includes: When the purge duration reaches a preset duration, the operation state of the fuel cell is controlled to be a purge stop state.

[0007] Optionally, controlling the operating state of the fuel cell according to the purge duration includes: When the purge duration does not reach the preset duration, the average voltage value of all the battery stacks in the fuel cell reaches the preset voltage threshold or the high-frequency impedance value of all the battery stacks in the fuel cell reaches the preset high-frequency impedance threshold, the operating state of the fuel cell is controlled to stop purge state.

[0008] Optionally, the preset duration is obtained in the following manner: Determining the operating time and operating power of the fuel cell when the ambient temperature is less than the preset temperature threshold; The preset duration is calculated based on the operating duration and the operating power.

[0009] Optionally, determining the target flow rate according to the stack temperature includes: Calculate the average temperature of the coolant entering the fuel cell stack and exiting the fuel cell stack according to the outlet temperature and the inlet temperature; The target flow rate is determined according to the average temperature and a preset corresponding relationship, wherein the preset corresponding relationship is used to characterize the corresponding relationship between the average temperature and the flow rate.

[0010] Optionally, controlling the preset gas to purge the moisture stored in the fuel cell stack at the target flow rate includes: The rotation speed of the air compressor is controlled to reach a rotation speed corresponding to the target flow rate, so that the preset gas can purge the moisture stored in the fuel cell stack at the target flow rate.

[0011] Optionally, after the ambient temperature of the fuel cell is less than a preset temperature threshold, the method further includes: Reducing the current value of the stack in the fuel cell to a target current according to a load reduction slope, wherein the target current is the operating current of the stack when the fuel cell is purged; The step of determining the stack temperature of the fuel cell comprises: When the current of the fuel cell stack reaches the target current, the fuel cell stack temperature of the fuel cell is determined.

[0012] In a second aspect, the present disclosure provides a control device for a fuel cell, comprising a first determination module, a second determination module, and a control module; The first determination module is used to determine the stack temperature of the fuel cell when the ambient temperature of the fuel cell is less than a preset temperature threshold, wherein the stack temperature is the inlet temperature of the coolant entering the stack and the outlet temperature of the coolant exiting the stack in the fuel cell, and the preset temperature threshold is the maximum ambient temperature value of the fuel cell when cold shutdown occurs; The second determination module is used to determine the target flow rate according to the stack temperature; The control module is used to control the preset gas to purge the moisture stored in the fuel cell stack at the target flow rate, obtain the purge duration, and control the operating state of the fuel cell according to the purge duration.

[0013] Optionally, the control module is used to: When the purge duration reaches a preset duration, the operation state of the fuel cell is controlled to be a purge stop state.

[0014] Optionally, the control module is used to: When the purge duration does not reach the preset duration, the average voltage value of all the battery stacks in the fuel cell reaches the preset voltage threshold or the high-frequency impedance value of all the battery stacks in the fuel cell reaches the preset high-frequency impedance threshold, the operating state of the fuel cell is controlled to stop purge state.

[0015] Optionally, the preset duration is obtained in the following manner: Determining the operating time and operating power of the fuel cell when the ambient temperature is less than the preset temperature threshold; The preset duration is calculated according to the operating duration and the operating power.

[0016] Optionally, the second determining module includes: A calculation module, used to calculate the average temperature of the coolant entering the fuel cell stack and exiting the fuel cell stack according to the outlet temperature and the inlet temperature; The third determination module is used to determine the target flow rate according to the average temperature and a preset corresponding relationship, wherein the preset corresponding relationship is used to characterize the corresponding relationship between the average temperature and the flow rate.

[0017] Optionally, the control module is used to: The rotation speed of the air compressor is controlled to reach a rotation speed corresponding to the target flow rate, so that the preset gas can purge the moisture stored in the fuel cell stack at the target flow rate.

[0018] Optionally, the device further comprises: A load reduction module, used to reduce the current value of the stack in the fuel cell to a target current according to a load reduction slope, wherein the target current is the operating current of the stack when the fuel cell is purged; The first determining module is used for: When the current of the fuel cell stack reaches the target current, the fuel cell stack temperature of the fuel cell is determined.

[0019] In a third aspect, the present disclosure provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the methods provided in the first aspect of the present disclosure.

[0020] In a fourth aspect, the present disclosure provides a controller, comprising: a memory having a computer program stored thereon; A processor is used to execute the computer program in the memory to implement the steps of any one of the methods provided in the first aspect of the present disclosure.

[0021] In a fifth aspect, the present disclosure provides a fuel cell system, comprising the controller provided in the fourth aspect of the present disclosure.

[0022] Through the above technical solution, the temperature of the fuel cell stack corresponding to the cold shutdown state of the fuel cell is determined, and the target flow rate is determined according to the temperature of the fuel cell stack, thereby avoiding excessive flow rate and too small flow rate to purge the fuel cell stack. After that, the preset gas can be controlled to purge the moisture stored in the fuel cell stack at the target flow rate, and the purge time can be obtained at the same time, and the operating state of the fuel cell can be controlled according to the purge time. By purging the moisture generated inside the fuel cell stack with a preset gas at a target flow rate and controlling the operating state of the fuel cell according to the purge time, the occurrence of excessive whistling and ineffective purge can be reduced, and the damage to the fuel cell engine can be reduced, thereby increasing the service life of the fuel cell.

[0023] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings: Figure 1 is a schematic diagram showing a control method of a fuel cell according to an exemplary embodiment of the present disclosure.

[0025] Figure 2 The figure is a flow chart showing a control method of a fuel cell according to an exemplary embodiment of the present disclosure.

[0026] Figure 3 is a schematic diagram showing a fuel cell system according to an exemplary embodiment of the present disclosure.

[0027] Figure 4 is a schematic diagram showing a control device for a fuel cell according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0028] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0029] The fuel cell engine will produce a large amount of water during operation, which may cause excessive water to remain in the engine pipes and parts of the proton exchange membrane after the fuel cell is shut down. If the fuel cell is left in a low temperature environment for a long time, the remaining water will freeze and easily cause the proton transfer capacity of the proton exchange membrane to drop significantly, resulting in poor fuel cell engine performance. At the same time, the freezing of pipes and parts will greatly cause the parts to fail or the pipelines to be blocked, resulting in failure to start the fuel cell engine. Multiple reverse polarity will seriously damage the proton exchange membrane and reduce the life of the fuel cell engine.

[0030] In the related art, mainly when the fuel cell is in the shutdown state, air is input to the cathode of the fuel cell stack and purged at a large flow rate to blow out the excess moisture stored inside the stack, so as to keep the inside of the stack dry.

[0031] However, the inventors have found that when the water stored in the fuel cell stack is purged by the method in the related art, when the flow rate of the delivered air is too large and the purge is carried out for a long time, the proton exchange membrane may be too dry, and the life of the proton exchange membrane may be reduced, and excessive purge may occur. Among them, excessive purge can be caused by the proton exchange membrane of the fuel cell being too dry, hydrogen and oxygen undergoing chemical reactions, and protons need to be transferred from the anode side to the cathode side through the dragging effect of water in the exchange membrane. There is too little water in the membrane, which reduces the transmission capacity of protons. The proton exchange membrane repeatedly transforms from a dry state to a wet state, which increases its fatigue damage, causes the carbon carrier to break and fall off, and causes irreversible damage.

[0032] When the air flow is too small and the purge is performed in a short time, the water inside the stack cannot be dried out, which is considered ineffective purge. Ineffective purge can be caused by excessive water inside the fuel cell engine. After low-temperature storage, the parts and pipelines are prone to ice formation at water storage locations, resulting in poor gas transmission, low voltage of individual cells, and excessively high local temperatures, thereby reducing the life of the proton exchange membrane.

[0033] In view of this, the present disclosure provides a control method and a corresponding device for a fuel cell to solve the technical problems existing in the above-mentioned related technologies.

[0034] like Figure 1 As shown, Figure 1 is a schematic diagram showing a control method of a fuel cell according to an exemplary embodiment of the present disclosure, with reference to Figure 1 ,include: S101: When the ambient temperature of the fuel cell is less than a preset temperature threshold, determining the stack temperature of the fuel cell, wherein the stack temperature is the inlet temperature of the coolant entering the stack and the outlet temperature of the coolant exiting the stack in the fuel cell, and the preset temperature threshold is the maximum ambient temperature value at which the fuel cell undergoes cold shutdown; S102: determining a target flow rate according to the stack temperature; S103: Controlling a preset gas to purge the moisture stored in the fuel cell stack at the target flow rate, acquiring a purge duration, and controlling the operating state of the fuel cell according to the purge duration.

[0035] Through the above technical solution, the temperature of the fuel cell stack corresponding to the cold shutdown state of the fuel cell is determined, and the target flow rate is determined according to the temperature of the fuel cell stack, thereby avoiding excessive flow rate and too small flow rate to purge the fuel cell stack. After that, the preset gas can be controlled to purge the moisture stored in the fuel cell stack at the target flow rate, and the purge time can be obtained at the same time, and the operating state of the fuel cell can be controlled according to the purge time. By purging the moisture generated inside the fuel cell stack with a preset gas at a target flow rate and controlling the operating state of the fuel cell according to the purge time, the occurrence of excessive whistling and ineffective purge can be reduced, and the damage to the fuel cell engine can be reduced, thereby increasing the service life of the fuel cell.

[0036] In order to enable those skilled in the art to better understand the fuel cell control method provided by the present disclosure, the above steps are described in detail below with examples.

[0037] For example, the preset temperature threshold may be the maximum ambient temperature value at which the fuel cell undergoes a cold shutdown. Cold shutdown may be the process of shutting down the fuel cell under low ambient temperature. In this embodiment, when the ambient temperature is less than the preset temperature threshold, it may represent that the fuel cell may undergo a cold shutdown. When the fuel cell undergoes a cold shutdown, it is necessary to purge the moisture generated inside the stack to increase the service life of the fuel cell.

[0038] In this embodiment, when the ambient temperature of the fuel cell is less than the preset temperature threshold, the stack temperature of the fuel cell can be determined, and in the subsequent control method, the target flow rate of the input stack temperature can be determined according to the stack temperature, thereby avoiding excessive flow or too small flow input into the stack, resulting in excessive purge or ineffective purge. The stack temperature can be the inlet temperature of the coolant entering the stack and the outlet temperature of the coolant exiting the stack, which is not specifically limited in the embodiment of the present disclosure.

[0039] In a possible manner, after the ambient temperature of the fuel cell is less than a preset temperature threshold, the method further includes: Reducing the current value of the stack in the fuel cell to a target current according to a load reduction slope, wherein the target current is the operating current of the stack when the fuel cell is purged; The step of determining the stack temperature of the fuel cell comprises: When the current of the fuel cell stack reaches the target current, the fuel cell stack temperature of the fuel cell is determined.

[0040] It should be understood that the current of the fuel cell in normal operation and in cold shutdown is different, and the current corresponding to the fuel cell in cold shutdown is less than the current corresponding to the fuel cell in shutdown. When the ambient temperature is less than the preset temperature threshold, the fuel cell will change from the current in normal operation to the current corresponding to the cold shutdown state. Thus, after detecting that the ambient temperature is less than the preset temperature threshold, the fuel cell stack can be controlled to reduce the current to the target current according to the load reduction slope, wherein the load reduction slope can be the rate of change of the stack from high current to low current. The slope can be 80A / s, and the embodiments of the present disclosure do not make specific limitations on this. For example, after the ambient temperature is less than the preset temperature threshold, the 300A current in the fuel cell can be reduced to 18A at 80A / s, and the embodiments of the present disclosure do not make specific limitations on this.

[0041] When the current corresponding to the normal operation of the fuel cell stack is reduced to the target current, it can represent that the fuel cell is in the purging state at this time, and then the fuel cell stack temperature can be determined. This is not specifically limited in the embodiments of the present disclosure.

[0042] For example, after determining the temperature of the battery stack, the target flow rate can be determined according to the temperature of the battery stack. The target flow rate can then be used to control the flow rate of air entering the battery stack in the future, thereby preventing excessive or insufficient flow rate from being blown into the battery stack, thereby preventing excessive or ineffective purging.

[0043] In a possible manner, determining the target flow rate according to the stack temperature includes: Calculate the average temperature of the coolant entering the fuel cell stack and exiting the fuel cell stack according to the outlet temperature and the inlet temperature; The target flow rate is determined according to the average temperature and a preset corresponding relationship, wherein the preset corresponding relationship is used to characterize the corresponding relationship between the average temperature and the flow rate.

[0044] It should be understood that when determining the target flow rate according to the temperature of the battery stack, the target flow rate can be calculated according to the average temperature of the battery stack. The average temperature of the battery stack can be the average of the outlet temperature and the inlet temperature of the battery stack coolant, or the average of the temperature of the battery stack measured at multiple points, which is not specifically limited in the embodiments of the present disclosure.

[0045] In the disclosed embodiment, the average temperature of the stack can be calculated based on the inlet temperature and outlet temperature of the coolant, and then the target flow rate can be determined based on the average temperature and the preset corresponding relationship. The preset corresponding relationship is the relationship between the average temperature and the flow rate. For example, when the average temperature is 10o C, the flow rate may be 5m 2 / s, when the average temperature is 25 o C, the flow rate may be 3m 2 / s, and the embodiments of the present disclosure do not make any specific limitation on this.

[0046] For example, after determining the target flow rate, the preset gas can be controlled to blow into the moisture in the fuel cell stack at the target flow rate, wherein the preset gas can be air or a gas used to dry the moisture in the fuel cell stack, and the embodiments of the present disclosure do not make specific limitations on this.

[0047] In the disclosed embodiment, while controlling the preset gas to blow into the battery stack at the target flow rate, the purge duration can be obtained, and the battery stack can be controlled to stop purging according to the purge duration. For example, when the purge duration of the battery stack reaches 260s, the moisture in the battery stack has reached the standard expected by the user, and the battery stack can be controlled to stop purging, thereby avoiding excessive purging.

[0048] By purging the moisture generated inside the fuel cell stack with gas at a target flow rate and controlling the operating state of the fuel cell according to the purge duration, excessive whistling and ineffective purge can be reduced, while damage to the fuel cell engine can be reduced, thereby increasing the service life of the fuel cell.

[0049] In a possible manner, controlling the operating state of the fuel cell according to the purge duration includes: When the purge duration reaches a preset duration, the operation state of the fuel cell is controlled to be a purge stop state.

[0050] It should be understood that when purging the inside of the fuel cell stack, over-purging may occur when the purging time is too long. Therefore, it can be judged whether the over-purging state is reached according to the purging time. The preset time can be the maximum time for purging the fuel cell stack when the fuel cell is in the purging state.

[0051] In the embodiment of the present disclosure, when the purge duration reaches a preset duration, it may represent that the purge duration of the fuel cell in the purge state reaches the maximum purge duration. At this time, the operating state of the fuel cell may be controlled to a stopped operating state, thereby avoiding excessive purge.

[0052] In a possible manner, controlling the operating state of the fuel cell according to the purge duration includes: When the purge duration does not reach the preset duration, the average voltage value of all the battery stacks in the fuel cell reaches the preset voltage threshold or the high-frequency impedance value of all the battery stacks in the fuel cell reaches the preset high-frequency impedance threshold, the operating state of the fuel cell is controlled to stop purge state.

[0053] It should be understood that when the purge duration does not reach the preset duration, the water in the fuel cell stack may be purged. At this time, the average voltage value or the high-frequency impedance value of the stack can be used to determine whether the fuel cell has completed the purge. The preset voltage threshold can be used to characterize the critical voltage threshold for the completion of the purge of the fuel cell stack. The preset high-frequency impedance threshold can be used to characterize the critical high-frequency impedance threshold for the completion of the purge of the fuel cell stack. Among them, the preset voltage threshold can be 0.68V, and the preset high-frequency impedance threshold can be 300mΩ, which is not specifically limited in the embodiments of the present disclosure.

[0054] In the disclosed embodiment, when the average voltage value of all the stacks in the fuel cell is greater than the preset voltage threshold, it can represent that the water in the stack in the fuel cell has been blown dry, and the stack purge can be stopped at this time. When the high-frequency impedance value of all the stacks in the fuel cell reaches the preset high-frequency impedance threshold, it can represent that the water in the stack in the fuel cell has been blown dry, and the stack purge can be stopped. This can prevent the stack from being over-purged and ineffectively purged.

[0055] In a possible manner, the preset duration is obtained by: Determining the operating time and operating power of the fuel cell when the ambient temperature is less than the preset temperature threshold; The preset duration is calculated according to the operating duration and the operating power.

[0056] It should be understood that when the ambient temperature of the fuel cell is less than the preset temperature threshold, the preset duration can be calculated based on the operating time and operating power of the fuel cell, and the preset duration can be used to characterize the water production of the fuel cell when it is running during this period. The specific calculation method can be calculated by the method of calculating the preset duration in the relevant technology, which will not be repeated here. Among them, the preset duration can be related to the amount of water generated by the battery stack. When the amount of water generated by the battery stack reaches the target water volume, the preset duration can be set to 400s. When the amount of water generated by the battery stack does not reach the target water volume, the preset duration can be set to 200s. This is not specifically limited in the embodiments of the present disclosure.

[0057] In a possible manner, the controlling the preset gas to purge the moisture stored in the fuel cell stack at the target flow rate includes: The rotation speed of the air compressor is controlled to reach a rotation speed corresponding to the target flow rate, so that the preset gas can purge the moisture stored in the fuel cell stack at the target flow rate.

[0058] It should be understood that when controlling the blowing of the preset gas into the battery stack, it can be controlled by an air compressor. Among them, the air compressor can be used to compress air. In the embodiment of the present disclosure, the preset gas can be air, and then the air can be compressed by the air compressor, and the speed of the air compressor can be controlled so that the output preset gas is input into the battery stack according to the target flow rate, and the moisture stored in the battery stack is purged.

[0059] Reference Figure 2 , Figure 2 is a flow chart showing a method for controlling a fuel cell according to an exemplary embodiment of the present disclosure, such as Figure 2 As shown, the steps of the fuel cell control method specifically include: Step S201: Start.

[0060] Step S202: Determine whether the ambient temperature is greater than a preset temperature threshold. If the ambient temperature is greater than the preset temperature threshold, proceed to step S204; otherwise, proceed to step S202.

[0061] Step S203: The fuel cell is cold shut down.

[0062] Step S204: Shut down at normal temperature and proceed to step S212.

[0063] Step S205: The current is reduced to 18A for continuous operation.

[0064] Step S206: Determine the target flow rate according to the temperature of the fuel cell stack; determine the preset duration according to the operating time and operating power of the fuel cell stack.

[0065] Step S207: Purge the interior of the fuel cell stack according to the target flow rate.

[0066] Step S208: Determine whether the purge time is less than the preset time. If not, proceed to step S211; otherwise, proceed to steps S209 and S210.

[0067] Step S209: determine whether the high-frequency impedance value is greater than a preset high-frequency impedance threshold, if yes, proceed to step S211.

[0068] Step S210: determine whether the average voltage is greater than a preset voltage threshold, if yes, proceed to step S211.

[0069] Step S211: The fuel cell is shut down.

[0070] Step S212: End.

[0071] The specific implementation methods of the above-mentioned process steps have been illustrated in detail above and will not be repeated here. In addition, it should be understood that for the above-mentioned system embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations, but those skilled in the art should know that the present disclosure is not limited to the order of actions described above. Secondly, those skilled in the art should also know that the embodiments described above belong to preferred embodiments, and the steps involved are not necessarily required by the present disclosure.

[0072] Through the above technical solution, the temperature of the fuel cell stack corresponding to the cold shutdown state of the fuel cell is determined, and the target flow rate is determined according to the temperature of the fuel cell stack, thereby avoiding excessive flow rate and too small flow rate to purge the fuel cell stack. After that, the preset gas can be controlled to purge the moisture stored in the fuel cell stack at the target flow rate, and the purge time can be obtained at the same time, and the operating state of the fuel cell can be controlled according to the purge time. By purging the moisture generated inside the fuel cell stack with a preset gas at a target flow rate and controlling the operating state of the fuel cell according to the purge time, the occurrence of excessive whistling and ineffective purge can be reduced, and the damage to the fuel cell engine can be reduced, thereby increasing the service life of the fuel cell.

[0073] In practical applications, refer to Figure 3 , Figure 3 is a schematic diagram showing a fuel cell system according to an exemplary embodiment of the present disclosure. Figure 3 As shown, the fuel cell may include a radiator 1, a thermostat 2, a coolant inlet temperature sensor 3, a coolant outlet temperature sensor 4, a water pump 5, an air inlet temperature sensor 6, an air inlet pressure sensor 7, an intake shut-off valve 8, a humidifier 9, an intercooler 10, an air compressor, an ambient temperature sensor 12, an air filter 13, a bypass valve 14, a tail exhaust silencer 15, and a back pressure valve 16, wherein the stack, the coolant outlet temperature sensor 4, and the thermostat 2 may constitute a first circuit, and all of them communicate with the controller. The stack, the coolant outlet temperature sensor 4, the radiator 1, and the thermostat 2 may constitute a second circuit, and all of them communicate with the controller. The first circuit may be used to heat the stack, and the second circuit may be used to dissipate heat from the stack, so that the stack remains within a normal temperature range.

[0074] The ambient temperature sensor 12 is arranged at the input port of the air compressor 11, and the output port of the air compressor is connected to the humidifier 9 through the intercooler 10, and the humidifier 9 is connected to the fuel cell stack through the air intake stop valve 8. The air compressor can input the compressed gas into the fuel cell stack through the intercooler 10 and the humidifier 9, and the water outlet of the fuel cell stack is connected to the humidifier 9 through the back pressure valve 16, and then connected to the tail exhaust silencer 15 through the humidifier 9. The intercooler 10 can also be connected to the tail exhaust silencer 15 through the bypass valve 14. The controller of the air compressor, the air intake stop valve 8, the back pressure valve 16, and the bypass valve 14 all communicate with the controller; The specific control process is as follows: The system corresponding to the fuel cell determines whether the current ambient temperature reaches 0°C based on the ambient temperature sensor 12. If it is lower than 0°C, the fuel cell is controlled to enter the cold shutdown state, otherwise, it enters the normal temperature shutdown state, where 0°C can be the preset temperature threshold.

[0075] At the same time, the preset duration can be estimated based on the operating time and operating power of the fuel cell. The controller calculates the water production of the proton exchange membrane during the operation of the fuel cell through the operating power and operating time. When the water production reaches the target water volume calibrated in the early stage, the purge time is set to 400s; if the target water production is not reached, the purge time is set to 200s.

[0076] When the controller issues a cold shutdown command, the current is reduced to the preset current of 18A at a certain load reduction slope of 80A / s, and the load is continuously pulled during the purge period according to the current value in the series battery stack.

[0077] At this time, the controller determines the target flow rate by the average temperature of the coolant entering and leaving the stack. For example, the current corresponding stack temperature is determined by the average value of the inlet temperature of the coolant entering the stack and the outlet temperature of the coolant leaving the stack, and the target flow rate is determined based on the correspondence between the average temperature and flow rate calibrated in the previous period. The higher the average temperature, the smaller the target flow rate, and the lower the average temperature, the larger the target flow rate.

[0078] The controller controls the speed of the air compressor 11 to reach the target flow rate, controls the air intake stop valve 8 to be continuously fully opened, the bypass valve 14 to be fully closed, and the back pressure valve 16 to perform closed-loop regulation according to the preset air inlet pressure in the cold shutdown state.

[0079] Then the controller controls the speed of the water pump 5 so that the temperature difference between the inlet and outlet temperatures of the coolant is less than 4°C, and the thermostat 2 is in a fully closed state, so that the coolant runs in the first circuit. When the temperature of the battery stack is greater than 72°C, the thermostat 2 can be opened to allow part of the coolant to flow through the second circuit. If the temperature of the battery stack is lower than 70°C, the thermostat 2 is closed and the cooling fan is output at the minimum duty cycle.

[0080] When the purge time reaches the preset time, the purge is stopped. When the purge time does not reach the preset time, the high-frequency impedance value of the battery stack during the purge process is detected by the electrochemical workstation. When it reaches 300mΩ, the purge is stopped; or the voltage of the battery stack is measured. When the average voltage value of the battery stack is less than 0.68V, the purge is stopped.

[0081] Through the above technical solution, the purge state of the cold shutdown can be judged when the fuel cell is in a low-temperature environment, so that the purge degree can be determined according to the current operating conditions of the fuel cell, which can avoid damage to the fuel cell due to excessive or insufficient purge, reduce the risk of blind purge to the proton exchange membrane of the fuel cell, and improve the stability of the next startup, thereby increasing the service life of the fuel cell.

[0082] Based on the same concept, this embodiment also provides a control device for a fuel cell, referring to Figure 4 , Figure 4 is a schematic diagram showing a control device 400 for a fuel cell according to an exemplary embodiment of the present disclosure, such as Figure 4 As shown, it includes a first determination module 401, a second determination module 402 and a control module 403; The first determination module 401 is used to determine the stack temperature of the fuel cell when the ambient temperature of the fuel cell is less than a preset temperature threshold, wherein the stack temperature is the inlet temperature of the coolant entering the stack and the outlet temperature of the coolant exiting the stack in the fuel cell, and the preset temperature threshold is the maximum ambient temperature value of the fuel cell when cold shutdown occurs; The second determination module 402 is used to determine the target flow rate according to the stack temperature; The control module 403 is used to control the preset gas to purge the moisture stored in the fuel cell stack at the target flow rate, obtain the purge duration, and control the operating state of the fuel cell according to the purge duration.

[0083] Optionally, the control module 403 is used to: When the purge duration reaches a preset duration, the operation state of the fuel cell is controlled to be a purge stop state.

[0084] Optionally, the control module 403 is used to: When the purge duration does not reach the preset duration, the average voltage value of all the battery stacks in the fuel cell reaches the preset voltage threshold or the high-frequency impedance value of all the battery stacks in the fuel cell reaches the preset high-frequency impedance threshold, the operating state of the fuel cell is controlled to stop purge state.

[0085] Optionally, the preset duration is obtained in the following manner: Determining the operating time and operating power of the fuel cell when the ambient temperature is less than the preset temperature threshold; The preset duration is calculated according to the operating duration and the operating power.

[0086] Optionally, the second determining module 402 includes: A calculation module, used to calculate the average temperature of the coolant entering the fuel cell stack and exiting the fuel cell stack according to the outlet temperature and the inlet temperature; The third determination module is used to determine the target flow rate according to the average temperature and a preset corresponding relationship, wherein the preset corresponding relationship is used to characterize the corresponding relationship between the average temperature and the flow rate.

[0087] Optionally, the control module 403 is used to: The rotation speed of the air compressor is controlled to reach a rotation speed corresponding to the target flow rate, so that the preset gas can purge the moisture stored in the fuel cell stack at the target flow rate.

[0088] Optionally, the fuel cell control device 400 further includes: A load reduction module, used to reduce the current value of the stack in the fuel cell to a target current according to a load reduction slope, wherein the target current is the operating current of the stack when the fuel cell is purged; The first determining module 401 is used for: When the current of the fuel cell stack reaches the target current, the fuel cell stack temperature of the fuel cell is determined.

[0089] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0090] Based on the same concept, this embodiment further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps of the fuel cell control method disclosed in this embodiment are implemented.

[0091] Based on the same concept, this embodiment also provides a controller, including: a memory having a computer program stored thereon; The processor is used to execute the computer program in the memory to implement the steps of the fuel cell control method disclosed in this embodiment.

[0092] Based on the same concept, this embodiment also provides a fuel cell system, including the controller provided by this embodiment.

[0093] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0094] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0095] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for controlling a fuel cell, characterized in that: include: When the ambient temperature of the fuel cell is less than a preset temperature threshold, the stack temperature of the fuel cell is determined, wherein the stack temperature is the inlet temperature of the coolant entering the stack and the outlet temperature of the coolant exiting the stack in the fuel cell, and the preset temperature threshold is the maximum ambient temperature value of the fuel cell when cold shutdown occurs; Determining a target flow rate according to the stack temperature; The preset gas is controlled to purge the moisture stored in the fuel cell stack at the target flow rate, and the purge duration is obtained at the same time. The operating state of the fuel cell is controlled according to the purge duration.

2. The fuel cell control method according to claim 1, characterized in that: The controlling the operating state of the fuel cell according to the purge duration includes: When the purge duration reaches a preset duration, the operation state of the fuel cell is controlled to be a purge stop state.

3. The fuel cell control method according to claim 2, characterized in that: The controlling the operating state of the fuel cell according to the purge duration includes: When the purge duration does not reach the preset duration, the average voltage value of all the battery stacks in the fuel cell reaches the preset voltage threshold or the high-frequency impedance value of all the battery stacks in the fuel cell reaches the preset high-frequency impedance threshold, the operating state of the fuel cell is controlled to stop purge state.

4. The fuel cell control method according to claim 2 or 3, characterized in that: The preset duration is obtained in the following manner: Determining the operating time and operating power of the fuel cell when the ambient temperature is less than the preset temperature threshold; The preset duration is calculated according to the operating duration and the operating power.

5. The fuel cell control method according to claim 1, characterized in that: Determining the target flow rate according to the stack temperature includes: Calculate the average temperature of the coolant entering the fuel cell stack and exiting the fuel cell stack according to the outlet temperature and the inlet temperature; The target flow rate is determined according to the average temperature and a preset corresponding relationship, wherein the preset corresponding relationship is used to characterize the corresponding relationship between the average temperature and the flow rate.

6. The fuel cell control method according to claim 1, characterized in that: The controlling the preset gas to purge the moisture stored in the fuel cell stack at the target flow rate includes: The rotation speed of the air compressor is controlled to reach a rotation speed corresponding to the target flow rate, so that the preset gas can purge the moisture stored in the fuel cell stack at the target flow rate.

7. The fuel cell control method according to claim 1, characterized in that: After the ambient temperature of the fuel cell is less than a preset temperature threshold, the method further includes: Reducing the current value of the stack in the fuel cell to a target current according to a load reduction slope, wherein the target current is the operating current of the stack when the fuel cell is purged; The step of determining the stack temperature of the fuel cell comprises: When the current of the fuel cell stack reaches the target current, the fuel cell stack temperature of the fuel cell is determined.

8. A control device for a fuel cell, characterized in that: It includes a first determining module, a second determining module and a control module; The first determination module is used to determine the stack temperature of the fuel cell when the ambient temperature of the fuel cell is less than a preset temperature threshold, wherein the stack temperature is the inlet temperature of the coolant entering the stack and the outlet temperature of the coolant exiting the stack in the fuel cell, and the preset temperature threshold is the maximum ambient temperature value of the fuel cell when cold shutdown occurs; The second determination module is used to determine the target flow rate according to the stack temperature; The control module is used to control the preset gas to purge the moisture stored in the fuel cell stack at the target flow rate, obtain the purge duration, and control the operating state of the fuel cell according to the purge duration.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method described in any one of claims 1 to 8 are implemented.

10. A controller, characterized in that: include: a memory having a computer program stored thereon; A processor, configured to execute the computer program in the memory to implement the steps of the method according to any one of claims 1 to 8.

11. A fuel cell system, characterized in that: Comprising a controller as claimed in claim 10.

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