Method for detecting air leakage of cathode and related device

Abstract

The invention relates to a method for detecting air leakage of a cathode and a related device. The method includes acquiring a cathode pressure of a cathode of the fuel cell system during shutdown of the fuel cell system. The method further comprises the step of obtaining the environment pressure of the environment where the fuel cell system is located in the shutdown process. Further, the method includes determining an air leakage condition of a cathode of the fuel cell system based on the cathode pressure and the ambient pressure. In this way, the air leakage state of the cathode of the fuel cell system can be detected, so that treatment measures can be taken in the event of air leakage. Therefore, the situation of air start or hydrogen starvation of the fuel cell system in the next start process can be avoided, and further the membrane electrode can be prevented from being damaged.

Description

Technical Field

[0001] The present disclosure relates to the technical field of fuel cells, and more particularly, to a method and related device for detecting air leakage of a cathode. Background Art

[0002] Fuel cells have the advantages of high energy conversion efficiency and pollution-free emissions, and are currently used in more and more fields. For example, fuel cells have become a type of widely used vehicle power battery. A fuel cell generally includes a cathode and an anode. The cathode includes an oxidizing gas, such as oxygen; the anode includes a fuel gas, such as hydrogen or methanol, etc. The fuel cell generates electrical energy through an electrochemical reaction between the oxidizing gas and the fuel gas.

[0003] During the operation of a fuel cell, a continuous supply of fuel gas and oxidizing gas is required. Therefore, fuel cells generally exist in the form of a fuel cell system. In a fuel cell system, there are subsystems for supplying fuel gas and oxidizing gas, and these subsystems usually include a series of pipelines and valves. As the operating time of the fuel cell system increases, these pipelines and valves may malfunction or age, resulting in gas leakage in the fuel cell system. Summary of the Invention

[0004] Embodiments of the present disclosure provide a method, device, controller, fuel cell system, and medium for detecting air leakage of a cathode. In the embodiments of the present disclosure, the cathode pressure of the cathode of the fuel cell system during the shutdown process of the fuel cell system can be obtained, and the ambient pressure of the environment where the fuel cell system is located during the shutdown process can be obtained, and based on the cathode pressure and the ambient pressure, the air leakage state of the fuel cell system can be determined. In this way, it is possible to detect the air leakage state of the cathode of the fuel cell system, thereby avoiding the air-air start or hydrogen starvation of the fuel cell system caused by the air leakage of the cathode, and avoiding the accelerated aging or damage of the membrane electrode.

[0005] In the first aspect of the present disclosure, a method for detecting air leakage of a cathode is provided. The method includes obtaining the cathode pressure of the cathode of the fuel cell system during the shutdown process of the fuel cell system. The method further includes obtaining the ambient pressure of the environment where the fuel cell system is located during the shutdown process. In addition, the method further includes determining the air leakage state of the cathode of the fuel cell system based on the cathode pressure and the ambient pressure.

[0006] In a second aspect of the present disclosure, there is provided an apparatus for detecting air leakage of a cathode. The apparatus includes a cathode pressure acquisition module configured to acquire the cathode pressure of a fuel cell system during the shutdown process of the fuel cell system. The apparatus further includes an ambient pressure acquisition module configured to acquire the ambient pressure of the environment where the fuel cell system is located during the shutdown process. In addition, the apparatus further includes a leakage determination module configured to determine the air leakage state of the cathode of the fuel cell system based on the cathode pressure and the ambient pressure.

[0007] In a third aspect of the present disclosure, there is provided a controller. The controller includes one or more processors; and a storage device for storing one or more programs, which when executed by the one or more processors, cause the one or more processors to implement the method provided according to the first aspect of the present disclosure.

[0008] In a fourth aspect of the present disclosure, there is provided a fuel cell system. The fuel cell system includes the controller provided according to the third aspect of the present disclosure.

[0009] In a fifth aspect of the present disclosure, there is provided a machine-readable storage medium. Machine-executable instructions are stored on the machine-readable storage medium, and the machine-executable instructions are executed by a processor to implement the method provided according to the first aspect of the present disclosure.

[0010] It should be understood that the content described in the summary of the invention section is not intended to limit the key or important features of the embodiments of the present disclosure, nor to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. Brief Description of the Drawings

[0011] In combination with the drawings and with reference to the following detailed description, the above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent. In the drawings, the same or similar reference numerals denote the same or similar elements, where:

[0012] Figure 1 A schematic diagram of a fuel cell system in which multiple embodiments of the present disclosure can be implemented is shown;

[0013] Figure 2 A flowchart of a method for detecting air leakage of a cathode according to some embodiments of the present disclosure is shown;

[0014] Figure 3 A schematic curve diagram of the cathode pressure of a fuel cell system during the shutdown process according to some embodiments of the present disclosure is shown;

[0015] Figure 4Shows another schematic curve diagram of the cathode pressure during the shutdown process of a fuel cell system according to some embodiments of the present disclosure;

[0016] Figure 5 Shows a flowchart of a method for detecting air leakage of a cathode according to some embodiments of the present disclosure;

[0017] Figure 6 Shows a block diagram of a device for detecting air leakage of a cathode according to some embodiments of the present disclosure; and

[0018] Figure 7 Shows a block diagram of a device that can implement multiple embodiments of the present disclosure. Detailed Description of Specific Embodiments

[0019] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although some embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Instead, these embodiments are provided to more thoroughly and completely understand the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not used to limit the protection scope of the present disclosure.

[0020] In the description of the embodiments of the present disclosure, the term "including" and its like should be understood as an open inclusion, that is, "including but not limited to". The term "based on" should be understood as "at least partially based on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first", "second", etc. may refer to different or the same objects. There may also be other explicit and implicit definitions hereinafter.

[0021] As described above, fuel gas or oxidizing gas leakage may occur in a fuel cell system for various reasons. The inventors of the present application have found through research that air leakage in the cathode of a fuel cell system affects the performance and lifespan of the fuel cell system. For example, in a proton exchange membrane fuel cell where the oxidizing gas is air and the fuel gas is hydrogen, during the shutdown process of the fuel cell system, the oxygen in the air at the cathode is depleted, and the pressure of the hydrogen in the anode is maintained. If there is air leakage at the cathode, air in the external environment may enter the cathode, resulting in the inability to deplete the oxygen in the cathode during the shutdown process of the fuel cell system. This part of the oxygen may permeate to the anode of the fuel cell system, leading to an air-air startup situation during the next startup of the fuel cell system, which may damage the membrane electrode. When the fuel cell system is in a shutdown state, the air flowing into the cathode from the outside may also continuously react with the hydrogen in the anode, consuming the hydrogen in the anode, resulting in a hydrogen starvation situation during the next startup process of the fuel cell system, which will also damage the membrane electrode of the fuel cell system. Therefore, in order to avoid a reduction in the performance and lifespan of the fuel cell system due to air leakage, it is necessary to detect air leakage in a timely manner. Currently, there is a lack of a suitable method for detecting air leakage in the cathode of a fuel cell system.

[0022] To this end, embodiments of the present disclosure propose a solution for detecting air leakage in the cathode. In embodiments of the present disclosure, the cathode pressure of the fuel cell system during the shutdown process of the fuel cell system can be obtained, as well as the ambient pressure of the environment in which the fuel cell system is located during this shutdown process. Based on the cathode pressure and the ambient pressure, the air leakage state of the fuel cell system can be determined.

[0023] In this way, it is possible to determine whether there is air leakage in the cathode of the fuel cell system based on the cathode pressure and the ambient pressure during the shutdown process of the fuel cell system, realizing the detection of the air leakage state of the cathode of the fuel cell system. In this way, the operating state of the fuel cell system can be monitored more comprehensively, and corresponding detection results can be provided in the case of air leakage in the cathode to remind the user or other devices to take corresponding treatment measures, such as reminding the user to maintain the fuel cell system, thereby avoiding a decline in the performance of the fuel cell system.

[0024] In embodiments of the present disclosure, a proton exchange membrane fuel cell in which the fuel gas in the anode is hydrogen and the oxidizing gas in the cathode is air is taken as an example for illustration. Exemplarily, Figure 1 shows a schematic diagram of a fuel cell system 100 in which multiple embodiments of the present disclosure can be implemented. Refer to Figure 1, the fuel cell system 100 may include a fuel cell stack 101. The fuel cell stack 101 may include an anode 102 and a cathode 103. Hydrogen in the anode 102 and air in the cathode 103 may undergo an electrochemical reaction on the membrane electrode of the fuel cell stack 101 to generate electrical energy. It should be understood that Figure 1 the fuel cell stack 101 in is only a schematic illustration for explanation. In some embodiments, the fuel cell stack 101 may include a plurality of single-cell batteries connected in series, and each single-cell battery may include a cathode, an anode, and a membrane electrode.

[0025] The fuel cell system 100 may further include a hydrogen injector 104, a water separator 105, a drain valve 106, a hydrogen discharge valve 107, and a hydrogen circulation pump 108. Among them, the hydrogen injector 104 may supply hydrogen from the hydrogen storage system to the anode 102 and control the hydrogen pressure and flow rate. The water separator 105 may separate the liquid water in the gas at the outlet of the anode 102 and discharge the liquid water through the drain valve 106. The hydrogen discharge valve 107 may also be referred to as a purge valve, and may discharge the impurity gas (such as nitrogen) when the concentration of the impurity gas in the anode 102 becomes high. The hydrogen circulation pump 108 may circulate the unreacted hydrogen at the outlet of the anode 102 to the inlet of the anode 102. The hydrogen injector 104, the water separator 105, the drain valve 106, the hydrogen discharge valve 107, the hydrogen circulation pump 108, and the anode 102 may be connected by pipelines to jointly form the anode subsystem (which may also be referred to as the anode loop) in the fuel cell system 100. In Figure 1 the flow direction of the pipelines and the gas or liquid in the pipelines is represented in the form of arrows.

[0026] The fuel cell system 100 may further include an air compressor 109, an upstream cut-off valve 110, a downstream cut-off valve 111, a bypass valve 112, and a tail exhaust 113. Among them, the air compressor 109 may pressurize the air to supply air to the cathode 103 of the fuel cell stack 101. The upstream cut-off valve 110 is in an open state during the operation of the fuel cell system 100 to introduce air into the cathode 103. When the fuel cell system 100 is in a shutdown state, the upstream cut-off valve 110 is closed. The downstream cut-off valve 111, also called an exhaust throttle valve, may discharge the reacted cathode gas, and may also adjust the gas pressure at the outlet of the cathode 103 and the flow rate of the gas supplied to the fuel cell stack 101. The bypass valve 112 may be opened when the upstream cut-off valve 110 is closed to discharge the air provided by the air compressor 109. The air compressor 109, the upstream cut-off valve 110, the downstream cut-off valve 111, the bypass valve 112, and the cathode 103 are connected by pipelines to jointly form the cathode subsystem (which may also be referred to as the cathode loop) in the fuel cell system 100. In Figure 1The flow direction of the pipeline and the gas or liquid in the pipeline is indicated in the form of an arrow. In the fuel cell system 100, the water and exhaust gas discharged from the anode subsystem and the exhaust gas discharged from the cathode subsystem can be discharged from the fuel cell system 100 through the tail exhaust 113.

[0027] The fuel cell system 100 may further include a thermal management subsystem (which may also be referred to as a cooling subsystem or a cooling circuit) composed of a thermostat 114, a radiator 115, and a cooling pump 116. The thermostat 114 can adjust the flow rate of the coolant circulating in the heat dissipation system by adjusting the opening degree to achieve precise temperature control. The radiator 115 can transfer the heat of the coolant to the environment and reduce the temperature of the coolant, thereby taking away the heat generated by the fuel cell stack 101. The cooling pump 116 can adjust the coolant flow rate by adjusting the rotational speed, and then control the temperature to keep the operating temperature of the fuel cell within a suitable range.

[0028] The fuel cell system 100 may further include a sensor 120. The sensor 120 may include, for example, sensors 120-1 to 120-4. The sensor 120-1 may be disposed at the gas outlet of the cathode 103 and can detect temperature and pressure. The sensor 120-2 may be disposed in the tail exhaust 113 of the fuel cell system 100 and can detect the hydrogen concentration in the gas discharged from the fuel cell system 200, and can also detect pressure. The sensor 120-3 may be disposed at the air inlet of the air compressor 109 and can detect the temperature, pressure, and humidity of the air entering the fuel cell system 100. The sensor 120-4 may be disposed at the air inlet of the cathode 103 and can detect temperature and pressure. It should be understood that the embodiments of the present disclosure do not limit the number, position, and type of sensors. For example, in some embodiments, the sensor 120-1 may include a temperature sensor and a pressure sensor, and the sensor 120-2 may include a pressure sensor and a hydrogen concentration sensor. In some embodiments, the fuel cell system 100 may further include more or fewer sensors.

[0029] The fuel cell system 100 further includes a fuel cell control unit (FCCU) 130. The FCCU 130 can control each component in the fuel cell system 100 to achieve overall control of the fuel cell system, including the management of hydrogen and air, energy conversion and supervision, fault diagnosis and handling, and communication with other systems. In some embodiments, the FCCU 130 can control the fuel cell system 100 to enter a shutdown process when receiving a shutdown signal.

[0030] In some embodiments, during the shutdown process of the fuel cell system 100, a large amount of air can be introduced into the air compressor 109 to purge the cathode 103. After the air purge lasts for a predetermined duration, the upstream cutoff valve 110 and the downstream cutoff valve 111 are closed to put the cathode 103 in a closed state, and the bypass valve 112 is opened to discharge the air introduced by the air compressor 109 through the tail exhaust 113. After that, the fuel cell stack 101 actively reduces the voltage by outputting current and voltage to consume the oxygen in the cathode 103. After the active voltage reduction ends, the anode subsystem starts to perform hydrogen purging. The hydrogen injector 104 injects hydrogen to make the pressure in the cathode 102 reach a predetermined pressure threshold, and the hydrogen discharge valve 107 is opened at a predefined frequency to dry the anode 102 through a continuous hydrogen flow. After that, the fuel cell system enters the cooling stage, and the temperature of the fuel cell stack 101 is gradually reduced by the cooling subsystem.

[0031] In some embodiments, the FCCU 130 can obtain the pressure detected by the sensor 120-1 or the sensor 120-2 and use it as the cathode pressure in the cathode 103. The FCCU 130 can obtain the pressure detected by the sensor 120-2 or the sensor 120-3 and use it as the ambient pressure. The FCCU 130 can determine the air leakage state of the cathode 103 based on the ambient pressure and the cathode pressure. In some embodiments, the FCCU 130 can also obtain the cathode pressure or the ambient pressure from other devices. In some embodiments, the FCCU 130 can send the air leakage state of the cathode 103 to other devices. Exemplarily, the fuel cell system 100 can be configured in a vehicle, and the FCCU 130 can send the air leakage state of the cathode 103 to the vehicle control unit (VCU) in the vehicle through the controller area network (CAN) bus.

[0032] It should be understood that Figure 1The fuel cell system 100 shown is only an example of the embodiments of the present disclosure and should not be construed as a limitation on the embodiments of the present disclosure. For example, in some embodiments, the oxidizing gas at the cathode in the fuel cell system 100 may be other types of gases, such as oxygen. In some embodiments, the fuel gas at the anode may be other types of gases, such as methanol. In the embodiments of the present disclosure, the names of the components in the fuel cell system 100 are only examples. In some embodiments, components with the same or similar functions may have different names. In some embodiments, the fuel cell system may also be referred to as a fuel cell power module (FCPM). In some embodiments, the fuel cell system 100 may further include more or fewer components. For example, it may further include an electrical and electronic subsystem or a direct current / direct current (DC / DC) converter. It should also be understood that the solutions provided in the embodiments of the present disclosure may also be applied to other types of fuel cell systems. The fuel cell systems in the embodiments of the present disclosure may be applied to various scenarios and may be configured as a power source or an auxiliary power source in various devices, including but not limited to vehicles, yachts, aerospace equipment, underwater power equipment, etc.

[0033] Figure 2 The flowchart of a method 200 for detecting an air leak at the cathode according to some embodiments of the present disclosure is shown. The method 200 may be executed by a device for detecting an air leak. The device may be configured in the fuel cell system or may be a device independent of the fuel cell system, and may include but is not limited to a processor, a computer, a chip, a chip system, or a server, etc. The device may also be implemented in a software and / or hardware manner. In some embodiments, the device may be a controller in the fuel cell system, such as the Figure 1 FCCU 130 in. For ease of description, the method 200 will be described exemplarily with the detection device as the execution subject hereinafter. The detection device may be, for example, the FCCU 130 or a program module in the FCCU 130. Figure 2 As shown, the method 200 may include block 202 to block 206.

[0034] In block 202, the detection device may obtain the cathode pressure of the cathode of the fuel cell system during the shutdown process of the fuel cell system. In some embodiments, a sensor for detecting the cathode pressure may be configured in the cathode of the fuel cell system, and the detection device may obtain the cathode pressure from the sensor. Exemplarily, in Figure 1In the fuel cell system 100 shown, the sensors 120-1 and 120-4 can be pressure sensors, and the detection device can obtain the detected pressure from the sensors 120-1 and / or 120-4 and use it as the cathode pressure. In some embodiments, the detection device can obtain the cathode pressure of the fuel cell system in real time during the shutdown process of the fuel cell system. In some embodiments, the detection device can obtain the pressure change of the cathode during the shutdown process after the fuel cell system has shut down.

[0035] In block 204, the detection device can obtain the ambient pressure of the environment in which the fuel cell system is located during the shutdown process. In some embodiments, a pressure sensor can be configured in the environment where the fuel cell system is located, and the detection device can obtain the ambient pressure from the pressure sensor configured in the environment. In some embodiments, the ambient pressure can be obtained from the fuel cell system, for example, from the sensors in the fuel cell system 100 described above. Exemplarily, in the fuel cell system 100 shown as Figure 1 above, the tail exhaust 113 and the intake port 109 of the air compressor can be directly connected to the environment. The sensors 120-2 and 120-3 can be pressure sensors, and the detection device can obtain the detected pressure from the sensors 120-2 and / or 120-3 and use it as the ambient pressure. In some embodiments, the ambient pressure can also be a predefined constant. In some embodiments, during the operation and shutdown processes of the fuel cell system, the fuel cell system can be in a stable environment. For example, the geographical area where the fuel cell system is located does not exceed a predetermined area range. In this case, the ambient pressure of the environment where the fuel cell system is located does not change significantly. Figure 1 above, the tail exhaust 113 and the intake port 109 of the air compressor can be directly connected to the environment. The sensors 120-2 and 120-3 can be pressure sensors, and the detection device can obtain the detected pressure from the sensors 120-2 and / or 120-3 and use it as the ambient pressure. In some embodiments, the ambient pressure can also be a predefined constant. In some embodiments, during the operation and shutdown processes of the fuel cell system, the fuel cell system can be in a stable environment. For example, the geographical area where the fuel cell system is located does not exceed a predetermined area range. In this case, the ambient pressure of the environment where the fuel cell system is located does not change significantly.

[0036] In block 206, the detection device determines the air leakage state of the cathode of the fuel cell system based on the cathode pressure and the ambient pressure. During the shutdown process of the fuel cell system, the cathode of the fuel cell system is in a closed state. If there is no air leakage in the cathode, due to factors such as the temperature change of the fuel cell stack or the chemical reaction of the gas in the air, the pressure of the cathode will change independently of the ambient pressure. If there is air leakage in the cathode, the cathode is in communication with the external environment, and the cathode pressure will be equal to the ambient pressure.

[0037] Exemplarily, Figure 3 shows a graph 300 of the cathode pressure of the fuel cell system during the shutdown process without air leakage in some embodiments of the present disclosure. In Figure 3Among them, the solid line 301 represents the cathode pressure of the fuel cell system, and the dashed line 302 represents the ambient pressure of the environment where the fuel cell system is located. During the normal operation of the fuel cell system and the air purge stage during the shutdown process of the fuel cell system, the air compressor will introduce high-pressure air into the cathode, so the cathode pressure will be greater than the ambient pressure.

[0038] At time t1, the air purge of the cathode ends, the upstream cut-off valve and the downstream cut-off valve of the fuel cell system close, the cathode is in a closed state, and the fuel cell stack actively reduces pressure, consuming the oxygen in the cathode. At this time, the cathode pressure begins to drop rapidly. At time t2, the output voltage of the fuel cell stack drops to a predetermined voltage threshold, and the active pressure reduction stops. After that, the remaining part of the oxygen in the cathode will react slowly with the hydrogen in the anode, and the relatively cold air previously introduced into the cathode by the air compressor will also be slowly heated by the fuel cell stack. If there is no air leakage in the cathode, the cathode pressure will first decrease slowly and then increase slowly. That is to say, after the active pressure reduction during the shutdown process ends, the pressure in the cathode changes slowly, which is different from the stable ambient pressure. If there is air leakage in the cathode, the cathode pressure will be equal to the ambient pressure.

[0039] Therefore, by comparing whether the cathode pressure during the shutdown process is the same as the ambient pressure, it can be determined whether there is air leakage in the cathode. In some embodiments, the detection device can determine that there is air leakage in the cathode when the cathode pressure is equal to the ambient pressure. In some embodiments, the detection device can determine that there is no air leakage in the cathode when it is determined that the cathode pressure during the shutdown process is not equal to the ambient pressure.

[0040] It should be noted that although it is shown in Figure 2 that block 202 is before block 204, it is not intended to limit the order of the operations performed at block 202 and block 204. On the contrary, the operations performed at block 202 and block 204 can be performed in reverse order or simultaneously. Through the above technical solution, it can be determined whether there is air leakage in the cathode of the fuel cell system based on the cathode pressure of the fuel cell system, and the detection of the air leakage state of the cathode can be realized. In this way, in the case of air leakage in the cathode, this air leakage state can be detected, and corresponding treatment measures can be taken on this basis to avoid damage to the membrane electrode during the next start-up process of the fuel cell due to air leakage in the cathode.

[0041] In some embodiments, in the aforementioned block 202, the detection device may use the pressure obtained from the pressure sensor at the air outlet of the cathode configured in the fuel cell system as the cathode pressure of the cathode. In a fuel cell stack, air enters the stack through the air inlet. The stack may include multiple single cells, and the air path of the cathode may be relatively long. After the air flows from the air inlet to the air outlet, the air will be affected by the temperature change of the entire stack. Therefore, the air at the air outlet of the cathode is more affected by the temperature of the stack than the air at the air inlet, and the pressure at the air outlet of the cathode will also change more. Therefore, if there is no air leakage, the difference between the pressure at the cathode air outlet and the ambient pressure is greater. By comparing the pressure at the cathode air outlet with the ambient pressure, it is possible to more easily and accurately determine whether there is air leakage in the cathode.

[0042] In some embodiments, the detection device may obtain the cathode pressure and the ambient pressure at multiple moments during the shutdown process, and based on this, determine whether there is air leakage in the cathode. The multiple moments may be, for example, three moments or four moments separated by a predetermined length. Exemplarily, the moments separated by a predetermined time length during the shutdown process may include a first moment, a second moment, and a third moment. The detection device may obtain the values of the cathode pressure and the ambient pressure at the first moment, at the second moment, and at the third moment. If it appears that the cathode pressure is equal to the ambient pressure at the first moment, the cathode pressure is equal to the ambient pressure at the second moment, and the cathode pressure is also equal to the ambient pressure at the third moment, the detection device may determine that there is air leakage in the cathode of the fuel cell system. The first moment, the second moment, and the third moment may be, for example, moments after the t2 moment in Figure 3 i.e., moments after the end of the active pressure reduction stage during the shutdown process.

[0043] Under normal circumstances, if there is no air leakage in the cathode, during the shutdown process of the fuel cell, the number of intersection points between the change curve of the cathode pressure and the change curve of the ambient pressure is less than three, that is, the number of times the cathode pressure is equal to the ambient pressure usually does not exceed two. Therefore, it is only necessary to compare the cathode pressure and the ambient pressure at three different moments to determine whether there is air leakage in the cathode. In this way, only a small number of cathode pressure values and ambient pressure values need to be processed, which can reduce the calculation amount and thus improve the processing efficiency.

[0044] In some embodiments, the detection device may determine whether there is air leakage in the cathode based on the cathode pressure and the ambient pressure at other numbers of moments separated by a predetermined time length during the shutdown process. The present disclosure does not limit this. Exemplarily, it is possible to determine whether there is air leakage based on the cathode pressure and the ambient pressure at other numbers of moments greater than three during the shutdown process, so as to make the determined result more accurate.

[0045] In some embodiments, the detection device may acquire the cathode pressure and the ambient pressure during the entire shutdown process of the fuel cell system. The detection device may compare the variation curve of the cathode pressure and the variation curve of the ambient pressure during the entire shutdown process. If the variation curve of the cathode pressure coincides with the variation curve of the ambient pressure, or the coincidence ratio is greater than a predetermined coincidence ratio threshold, the detection device may determine that there is an air leak in the cathode. If the variation curve of the cathode pressure does not coincide with the variation curve of the ambient pressure, or the coincidence ratio is less than the predetermined coincidence ratio threshold, the detection device may determine that there is no air leak in the cathode.

[0046] During the shutdown process of the fuel cell system, if there is no air leak in the cathode, the variation curve of the cathode pressure may also cross the variation curve of the ambient pressure multiple times. Therefore, if the cathode air leak is judged only based on the cathode pressure at certain moments, misjudgment may occur. However, determining whether there is a leak in the cathode based on the variation of the cathode pressure and the variation of the ambient pressure during the entire shutdown process can prevent misjudgment and make the detection of the cathode air leak more accurate.

[0047] In some embodiments, the detection device may also determine whether there is an air leak in the cathode based on the average value of the cathode pressure during the shutdown process. Exemplarily, the detection device may acquire the cathode pressure and the ambient pressure at each moment during the entire shutdown process, and the detection device may determine the average value of the cathode pressure and the average value of the ambient pressure during the entire shutdown process based on this. The detection device may determine that there is an air leak in the cathode when the average value of the cathode pressure is equal to the average value of the ambient pressure, and may determine that there is no air leak in the cathode when the average value of the cathode pressure is not equal to the average value of the ambient pressure.

[0048] In some embodiments, the basis for the detection device to determine whether the cathode pressure is equal to the ambient pressure may be that when it is determined that the difference between the cathode pressure and the ambient pressure is within a predetermined pressure difference range, it is determined that the cathode pressure is equal to the ambient pressure, and when it is determined that the difference between the cathode pressure and the ambient pressure exceeds the predetermined pressure difference range, it is determined that the cathode pressure is not equal to the ambient pressure. The detection device may, for example, determine whether the cathode pressure is equal to the ambient pressure at several moments based on this judgment basis, or may also determine whether the cathode pressure is equal to the ambient pressure during the entire shutdown process based on this judgment basis. In some embodiments, the predefined pressure difference range may be greater than or equal to -10 hPa and less than 10 hPa. By setting the pressure difference range, judgment errors caused by the system error of the detection device or the measurement error of the sensor can be avoided, and the reliability of the detection result of the air leak can be improved.

[0049] In some embodiments, the cathode pressure and the ambient pressure obtained by the detection device are the cathode pressure and the ambient pressure after the air compressor stops rotating during the shutdown process of the fuel cell system. In some embodiments, the detection device can obtain the operating state of the air compressor from the control unit of the air compressor, and on this basis, determine whether the air compressor has stopped rotating. In some embodiments, the detection device can obtain the fan blade speed of the air compressor from the control unit of the air compressor, and the detection device can determine that the air compressor has stopped rotating when the fan blade speed is zero.

[0050] During the shutdown process of the fuel cell system, if air leakage occurs at the cathode but the air compressor has not stopped rotating, the cathode pressure may not be equal to the ambient pressure. Exemplarily, Figure 4 FIG. 400 shows the cathode pressure of the fuel cell system during the shutdown process in the case of air leakage in some embodiments of the present disclosure. In Figure 4 it, the solid line 401 represents the cathode pressure of the fuel cell system, and the dashed line 402 represents the ambient pressure of the environment where the fuel cell system is located. As Figure 4 shown, at time t3, the air purge ends, the cathode of the fuel cell system is sealed, and the cathode pressure drops rapidly. When the air compressor has not stopped rotating, the air compressor continuously supplies air, and this part of the air is discharged through the bypass valve. If air leakage occurs at the cathode, the air supplied by the air compressor will enter the cathode from the leakage part, making the cathode pressure higher than the ambient pressure. After time t4 when the air compressor stops rotating, the cathode pressure will drop to be equal to the ambient pressure.

[0051] Therefore, if the determination of whether air leakage occurs at the cathode is based on the cathode pressure and the air pressure before the air compressor stops rotating, the result may be inaccurate. However, if the determination of whether air leakage occurs at the cathode is based on the cathode pressure and the air pressure after the air compressor stops rotating, the influence of the air compressor can be excluded, and an accurate detection result can be obtained. In some embodiments, the detection device can determine whether air leakage occurs at the cathode based on the cathode pressure and the air pressure after a predetermined delay duration (for example, it can be 1 second) after the air compressor stops rotating. At the moment when the air compressor stops rotating, the air flow flowing into the cathode through the air compressor may not stop immediately. Therefore, a delay duration can be set to completely exclude the influence of the air compressor on the detection result and make the detection result more accurate.

[0052] In some embodiments, during the shutdown process of the fuel cell system, the temperature of the fuel cell stack is too high, for example, higher than a predetermined temperature threshold (which can be 80 degrees Celsius, for example). The heat dissipation subsystem of the fuel cell system will cool down the fuel cell stack. That is to say, there can be a cooling stage during the shutdown process. The duration of the cooling stage can be predefined, for example, it can be 30 s. The cathode pressure and the ambient pressure obtained by the detection device can be the pressure of the cathode and the ambient pressure during this cooling stage. The detection device can detect whether air leakage occurs in the cathode based on the cathode pressure and the ambient pressure during this cooling stage. The temperature of the cathode changes greatly during the cooling stage. Therefore, if no air leakage occurs in the cathode, the cathode pressure will also change greatly, and there will be a more obvious difference from the ambient pressure. Based on this, it will be easier to determine whether the cathode pressure is equal to the ambient pressure. Therefore, based on the cathode pressure during the cooling stage, it is possible to more accurately determine whether air leakage occurs in the cathode.

[0053] In some embodiments, the detection device can also determine the change in the cathode temperature of the cathode of the fuel cell system before and after the cooling stage. In the case where the temperature change is greater than a predetermined temperature change threshold, the foregoing method 200 can be executed to obtain the cathode pressure and the ambient pressure during this cooling stage, and based on this, the air leakage state of the cathode can be determined. In some embodiments, the cathode temperature is determined by the detection device based on the temperature at the coolant outlet of the fuel cell stack. The detection device can obtain the temperature before the cooling stage and the temperature after the cooling stage at the coolant outlet. In the case where the difference between the two is greater than a predetermined temperature change threshold (such as 3 degrees Celsius), method 200 can be executed. The detection device does not execute method 200 and does not detect the air leakage of the cathode in the case where the difference between the two is less than the predetermined temperature change threshold. In this way, the detection result can be made more accurate and unnecessary inaccurate detections can be avoided.

[0054] In some embodiments, the detection of air leakage by the detection device is carried out during the shutdown process of the fuel cell system. The detection device can obtain the cathode pressure of the cathode and the ambient pressure of the environment where the fuel cell system is located in real time during the shutdown process of the fuel cell system, and can determine the air leakage state of the cathode immediately after the shutdown process ends. In this way, real-time detection of the air leakage state can be achieved. In the case where air leakage occurs in the cathode, the leakage state can be detected in time, so that corresponding treatment measures can be taken in time.

[0055] In some embodiments, the cathode pressure and the ambient pressure of the fuel cell system during the shutdown process can be stored in a predefined memory, for example Figure 1The FCCU 130 therein can obtain the cathode pressure and the ambient pressure during the shutdown process of the fuel cell system and store them in a predefined memory. The predefined memory can be, for example, the memory in the FCCU, or an independently configured memory, or a memory in the cloud. The detection device can obtain data related to the shutdown process of the fuel cell system from this memory. These data can include the cathode pressure and the ambient pressure during multiple shutdown processes of the fuel cell system. The detection device can determine the air leakage state of the cathode of the fuel cell system based on these data. In this case, the detection device can synthesize the detection results corresponding to multiple shutdown processes, thereby making the judgment of the air leakage state of the cathode more accurate.

[0056] In some embodiments, the cathode pressure and the ambient pressure based on which the detection device detects whether air leakage occurs in the cathode are obtained or collected during the normal shutdown process of the fuel cell system. The fuel cell system can have a normal shutdown process and a fault shutdown process. The FCCU of the fuel cell system can control the fuel cell system to enter the normal shutdown process or the fault shutdown process based on the type of the received shutdown signal. The detection device can determine whether the shutdown process of the fuel cell system is a normal shutdown process based on the type of this shutdown signal. There may be no active pressure reduction stage during the fault shutdown process. Therefore, regardless of whether air leakage occurs in the cathode, the cathode pressure during the fault shutdown process will be higher than the ambient pressure. Therefore, detecting the air leakage state of the cathode based on the cathode pressure and the ambient pressure during the normal shutdown process can make the detection result more accurate.

[0057] In some embodiments, after determining that air leakage occurs in the cathode of the fuel cell system, the detection device can send a fault signal associated with the air leakage to the upper-level system. In some embodiments, the fuel cell system is configured in a vehicle, and the upper-level system can be, for example, the VCU. The detection device can send a fault signal to the VCU after determining the air leakage, indicating that air leakage occurs in the cathode of the fuel cell system. In some embodiments, the detection device can indicate to the user that air leakage occurs in the cathode through a user interface, so that the user can obtain a reminder. In some embodiments, after determining that air leakage occurs in the cathode of the fuel cell system, the detection device can take predefined processing measures, such as locking the fuel cell system.

[0058] Figure 5 The flowchart of a method 500 for detecting air leakage in the cathode according to some embodiments of the present disclosure is shown. The method 500 can be executed by, for example, the detection device. In some embodiments, the detection device can control the fuel cell system, and the detection device can be, for example, the FCCU of the fuel cell system. Next, taking the detection device as the execution subject, the method 500 will be schematically described. Refer to Figure 5, Method 500 may include, for example, block 502 to block 522.

[0059] In block 502, the detection device receives a normal shutdown signal. In block 504, the detection device controls the fuel cell system to enter a normal shutdown process, and controls the fuel cell system to perform air purge and active pressure reduction. In block 506, the detection device obtains the rotational speed of the air compressor from the control unit of the air compressor in the fuel cell system, and the detection device determines that the rotational speed of the air compressor is zero. In block 508, the detection device controls the heat dissipation subsystem of the fuel cell system to cool the fuel cell stack, and the detection device determines that the fuel cell system enters a cooling stage. In block 510, the detection device obtains the temperature at the coolant outlet of the fuel cell stack in the fuel cell system. In block 512, based on the temperature at the coolant outlet, the detection device determines that the temperature change of the fuel cell stack during the cooling stage is greater than a predetermined temperature change threshold.

[0060] In block 514, the detection device obtains the cathode pressure of the cathode of the fuel cell stack during the cooling stage. In block 516, the detection device obtains the ambient pressure of the environment in which the fuel cell system is located during the cooling stage. The methods in block 514 and block 516 may be executed with reference to block 202 and block 204 in the foregoing method 200. In block 518, the detection device determines whether the difference between the cathode pressure and the ambient pressure is within a predetermined pressure difference range. If so, block 520 is executed; if not, block 522 is executed. In block 520, the detection device determines that there is an air leak in the cathode of the fuel cell system, and the detection device sends a fault signal to the upper-level system, and the fault signal indicates that there is an air leak in the cathode of the fuel cell system. In block 522, the detection device determines that there is no air leak in the cathode of the fuel cell stack.

[0061] In this way, it is possible to determine whether there is an air leak in the cathode of the fuel cell system during the shutdown process of the fuel cell system, and send a fault signal in the case of an air leak, so that the air leak situation of the cathode can be reported in time, and the air leak of the cathode can be processed. In this way, it is possible to avoid damage to the membrane electrode of the fuel cell system due to air leakage, and ensure the normal operation of the fuel cell system.

[0062] Figure 6 A block diagram of a device 600 for detecting air leakage of a cathode according to some embodiments of the present disclosure is shown. As Figure 6As shown, device 600 includes a cathode pressure acquisition module 602 configured to acquire the cathode pressure of the cathode of the fuel cell system during the shutdown process of the fuel cell system. Device 600 further includes an ambient pressure acquisition module 604 configured to acquire the ambient pressure of the environment where the fuel cell system is located during the shutdown process. In addition, device 600 further includes a leakage determination module 606 configured to determine the air leakage state of the cathode of the fuel cell system based on the cathode pressure and the ambient pressure.

[0063] In some embodiments, the shutdown process includes a cooling stage for reducing the temperature of the fuel cell stack in the fuel cell system, and the cathode pressure acquisition module 602 includes: a cathode temperature acquisition unit configured to acquire the cathode temperature of the cathode of the fuel cell system during the cooling stage; and a first cathode pressure acquisition unit configured to acquire the cathode pressure in response to the change in the cathode temperature during the cooling stage being greater than a predetermined temperature change threshold.

[0064] In some embodiments, the shutdown process includes a stage after the air compressor of the fuel cell system stops rotating, and the cathode pressure acquisition module 602 includes a second cathode pressure acquisition unit configured to acquire the cathode pressure during the stage after the air compressor stops rotating.

[0065] In some embodiments, the leakage determination module 606 includes: a leakage determination unit configured to determine that air leakage occurs in the cathode of the fuel cell system in response to the cathode pressure being equal to the ambient pressure.

[0066] In some embodiments, the cathode pressure includes multiple cathode pressures at multiple moments, the ambient pressure includes multiple ambient pressures at the multiple moments, the multiple moments are moments belonging to the shutdown process, and the leakage determination unit includes a first leakage determination unit configured to determine that air leakage occurs in the cathode of the fuel cell system in response to the multiple cathode pressures at the multiple moments being equal to the multiple ambient pressures.

[0067] In some embodiments, the leakage determination unit includes a second leakage determination unit configured to determine that air leakage occurs in the cathode of the fuel cell system in response to the average value of the cathode pressure during the shutdown process being equal to the average value of the ambient pressure.

[0068] In some embodiments, the leakage determination unit includes a third leakage determination unit configured to determine that air leakage occurs in the cathode of the fuel cell system in response to the difference between the cathode pressure and the ambient pressure during the shutdown process being within a predetermined pressure difference range.

[0069] In some embodiments, the shutdown process includes a normal shutdown process entered after the fuel cell system receives a normal shutdown signal.

[0070] In some embodiments, the cathode pressure acquisition module 602 includes a third cathode pressure acquisition unit configured to acquire the pressure at the air outlet of the cathode during the shutdown process as the cathode pressure.

[0071] In some embodiments, the device 600 further includes a fault signal sending module configured to send a fault signal associated with an air leak in response to determining that an air leak has occurred in the cathode of the fuel cell system.

[0072] Figure 7 FIG. shows a schematic block diagram of an exemplary device 700 that may be used to implement the embodiments of the present disclosure. The device 700 may correspond to the detection device in the foregoing method embodiments, Figure 1 and the FCCU 130 in Figure 7 may also be implemented using the device 700. As

[0073] shown, the device 700 includes a processor 701 that can perform various appropriate actions and processes according to computer program instructions stored in a read-only memory (ROM) 702 and loaded into a random access memory (RAM) 703. In the RAM 703, various programs and data required for the operation of the device 700 may also be stored. The processor 701, the ROM 702, and the RAM 703 are connected to each other via a bus 704. An input / output (I / O) interface 705 is also connected to the bus 704.

[0074] The various processes and processes described above, such as method 200 or method 500, may be executed by the processor 701. For example, in some embodiments, method 200 or method 500 may be implemented as a computer software program tangibly embodied in a machine-readable medium. In some embodiments, part or all of the computer program may be loaded and / or installed onto the device 700 via the ROM 702. When the computer program is loaded into the RAM 703 and executed by the processor 701, one or more actions of method 300, method 400, or method 500 described above may be executed.

[0074] The functions described above herein may be performed at least in part by one or more hardware logic components. For example, by way of non-limiting illustration, exemplary types of hardware logic components that may be used include: field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on a chip (SOCs), complex programmable logic devices (CPLDs), and the like.

[0075] The program code for implementing the methods of the present disclosure can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general purpose computer, a special purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the program codes cause the functions / operations specified in the flowchart and / or block diagram to be implemented. The program code can be executed entirely on the machine, partially on the machine, as a stand-alone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0076] In the context of the present disclosure, a machine-readable storage medium can be a tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of a machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. Additionally, although the operations are depicted in a particular order, this should be understood to require that the operations be performed in the particular order shown or in a sequential order, or that all illustrated operations be performed to achieve the desired result. In certain environments, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the above discussion, these should not be construed as limitations on the scope of the present disclosure. Certain features described in the context of separate embodiments can also be implemented in combination in a single implementation. Conversely, the various features described in the context of a single implementation can also be implemented separately or in any suitable sub-combination in multiple implementations.

[0077] Although the subject matter has been described in language specific to structural features and / or method logical acts, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are merely example forms of implementing the claims.

Claims

1. A method for detecting air leakage of a cathode, comprising: Obtaining the cathode pressure of the cathode of a fuel cell system during the shutdown process of the fuel cell system; Obtaining the ambient pressure of the environment where the fuel cell system is located during the shutdown process; and Determining the air leakage state of the cathode of the fuel cell system based on the cathode pressure and the ambient pressure.

2. The method according to claim 1, wherein the shutdown process includes a cooling stage for reducing the temperature of a fuel cell stack in the fuel cell system, and wherein obtaining the cathode pressure of the cathode of the fuel cell system includes: Obtaining the cathode temperature of the cathode of the fuel cell system during the cooling stage; And In response to a change in the cathode temperature during the cooling stage being greater than a predetermined temperature change threshold, obtaining the cathode pressure.

3. The method according to claim 1, wherein the shutdown process includes a stage after the air compressor of the fuel cell system stops rotating, and wherein obtaining the cathode pressure of the cathode of the fuel cell system during the shutdown process of the fuel cell system includes: Obtaining the cathode pressure during the stage after the air compressor stops rotating.

4. The method according to claim 1, wherein determining the air leakage state of the cathode of the fuel cell system based on the cathode pressure and the ambient pressure includes: In response to the cathode pressure being equal to the ambient pressure, determining that air leakage occurs in the cathode of the fuel cell system.

5. The method according to claim 4, wherein the cathode pressure includes multiple cathode pressures at multiple moments, the ambient pressure includes multiple ambient pressures at the multiple moments, the multiple moments are moments belonging to the shutdown process, and wherein determining that air leakage occurs in the cathode of the fuel cell system in response to the cathode pressure being equal to the ambient pressure includes: In response to the multiple cathode pressures at the multiple moments being equal to the multiple ambient pressures, determining that air leakage occurs in the cathode of the fuel cell system.

6. The method according to claim 4, wherein determining that air leakage occurs in the cathode of the fuel cell system in response to the cathode pressure being equal to the ambient pressure includes: In response to the average value of the cathode pressure during the shutdown process being equal to the average value of the ambient pressure, determining that air leakage occurs in the cathode of the fuel cell system.

7. The method according to claim 4, wherein determining that air leakage occurs in the cathode of the fuel cell system in response to the cathode pressure being equal to the ambient pressure includes: In response to the difference between the cathode pressure and the ambient pressure during the shutdown process being within a predetermined pressure difference range, determining that air leakage occurs in the cathode of the fuel cell system.

8. The method according to claim 1, wherein the shutdown process includes a normal shutdown process entered after the fuel cell system receives a normal shutdown signal.

9. The method according to claim 1, wherein obtaining the cathode pressure of the fuel cell system includes: Obtain the pressure at the air outlet of the cathode during the shutdown process as the cathode pressure.

10. The method according to any one of claims 1 to 9 further comprises: In response to determining that there is an air leak in the cathode of the fuel cell system, sending a fault signal associated with the air leak.

11. A device for detecting an air leak in a cathode, comprising: A cathode pressure acquisition module configured to acquire the cathode pressure of the cathode of the fuel cell system during the shutdown process of the fuel cell system; An ambient pressure acquisition module configured to acquire the ambient pressure of the environment where the fuel cell system is located during the shutdown process; And A leak determination module configured to determine the air leak state of the cathode of the fuel cell system based on the cathode pressure and the ambient pressure.

12. A controller, comprising: At least one processor; And A memory coupled to the at least one processor and having instructions stored thereon, the instructions when executed by the at least one processor causing the controller to perform the method according to any one of claims 1-10.

13. A fuel cell system, comprising the controller according to claim 12.

14. A machine-readable storage medium having machine-executable instructions stored thereon, wherein the machine-executable instructions are executed by a processor to implement the method according to any one of claims 1 to 10.

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