Method and system for early warning fluid leaks inside stack of fuel cell system

Abstract

The invention discloses a method for early warning fluid leakage in an electric pile of a fuel cell system, and the method comprises the following steps: enabling the electric pile to enter a preset mode, and in the preset mode, inputting hydrogen serving as fuel into an anode of the electric pile and inputting no gas into a cathode of the electric pile; detecting fluid pressure in a pipeline which is positioned outside the electric pile and is connected with a cathode of the electric pile or coolant pressure in a pipeline which is connected with a cooling cavity in the electric pile at a specified time interval; and determining whether the difference between the detected values of the two fluid pressures spaced apart from each other by a second time interval exceeds the standard and / or whether the difference between the detected values of the two coolant pressures spaced apart from each other by a second time interval exceeds the standard simultaneously or successively with a first standard and a second standard, the first standard being stricter than the second standard, and when the difference of the detection values is judged to exceed the standard according to a first standard, generating an early warning prompt that fluid leakage exists in the electric pile, and when the difference of the detection values is judged to exceed the standard according to a second standard, generating an instruction for preventing the electric pile from deflagration or antipole or giving an alarm.

Description

Technical Field

[0001] This application generally relates to methods and systems for identifying fluid leaks inside the stack of a fuel cell system, and in particular to providing early warning of fluid leaks or changes in the permeability of the proton exchange membrane in the stack of a fuel cell system based on cloud-based big data. Background Technology

[0002] As a type of new energy vehicle, fuel cell vehicles are increasingly being recognized and adopted by the market. The fuel cell stack is a crucial component of these vehicles, converting hydrogen and oxygen into electricity through an electrochemical reaction.

[0003] Generally, fuel cell stacks are equipped with various circuits, including hydrogen circuits, oxygen circuits, and coolant circuits. When the stack starts up, and the oxygen circuit is isolated from the outside air, pressurized hydrogen is first introduced into the stack through the hydrogen circuit. Subsequently, as the stack officially starts up, air is introduced into the oxygen circuit, and electricity is generated using an electrochemical converter (e.g., an ion exchange membrane) between the hydrogen and oxygen circuits. When the stack shuts down, the oxygen circuit typically stops supplying gas first, followed by the hydrogen circuit.

[0004] Because hydrogen is a flammable gas and the fuel cell stack generates electricity during operation, an abnormal hydrogen leak reaching a certain concentration can easily cause deflagration or reverse polarity issues. Therefore, to prevent such deflagration or reverse polarity problems, multiple hydrogen concentration sensors are typically installed in each circuit of the fuel cell stack to detect changes in hydrogen concentration. However, by the time this detection method determines that the hydrogen concentration has exceeded the limit, the concentration has often already reached a level that would cause the fuel cell stack to fail. This makes it impossible to detect and assess situations where hydrogen has leaked but has not yet reached a level that threatens stack failure.

[0005] Furthermore, hydrogen leakage can be categorized into leakage within the fuel cell stack (e.g., leakage between (single or double) electrodes) or leakage from the stack to the outside. For the aforementioned leakage within the stack, there is currently no reliable monitoring method in the prior art for identification. However, hydrogen leakage is often the first sign of stack failure. Therefore, effectively determining whether hydrogen is leaking between the electrodes within the stack is a crucial issue for the safe operation of fuel cells. Additionally, to monitor hydrogen leakage from within the stack, dedicated hydrogen sensors are typically installed inside. However, these dedicated sensors may malfunction under long-term operating conditions, resulting in the inability to provide real-time hydrogen monitoring. Therefore, considering a technique that does not use hydrogen sensors for real-time monitoring of internal hydrogen leakage within the stack could serve as a valuable supplement to existing dedicated hydrogen sensor monitoring, or even as a replacement, thereby reducing the overall complexity of the fuel cell system.

[0006] Furthermore, if the fuel cell stack continues to output (pump) current when hydrogen leakage has already occurred inside, the presence of hydrogen, air, and current inside the stack could potentially lead to burn-through or deflagration. Therefore, for the sake of safe operation of the fuel cell stack, it is also necessary to identify hydrogen leaks inside the stack. Summary of the Invention

[0007] In order to address the above-mentioned problems, this application aims to propose a novel method and system for early warning of fluid leakage in fuel cells in fuel cell stacks, thereby reliably identifying fluid leakage inside the fuel cell stack, providing early warning of failure of the entire fuel cell system, and improving the long-term operational safety of the fuel cell system.

[0008] According to one aspect of this application, a method for early warning of fluid leakage inside the stack of a fuel cell system is provided, comprising:

[0009] The fuel cell stack is brought into a predetermined mode in which gas is introduced into the anode of the fuel cell stack while no gas is introduced into the cathode of the fuel cell stack.

[0010] The fluid pressure in pipes located outside the fuel cell stack and connected to the cathode of the fuel cell stack, and / or the coolant pressure in pipes connected to the cooling chamber inside the fuel cell stack, are detected at a predetermined first time interval; and

[0011] Simultaneously or sequentially, the difference between two fluid pressure detection values ​​separated by a second time interval is determined using a first standard and a second standard to determine whether the difference between two coolant pressure detection values ​​separated by a second time interval exceeds the standard, wherein the second time interval is greater than or equal to the first time interval, and wherein the first standard is more stringent than the second standard. When the difference between the detection values ​​exceeds the standard according to the first standard, an early warning of fluid leakage inside the fuel cell stack is generated, and when the difference between the detection values ​​exceeds the standard according to the second standard, an instruction is generated to prevent the fuel cell stack from deflagration or reverse polarity, or an alarm is issued.

[0012] Optionally, in the process of judging the difference of the detected values ​​according to the first standard, the standard is deemed to have been exceeded only when the difference between the detected values ​​of two fluid pressures separated by a second time interval and / or the difference between the detected values ​​of two coolant pressures separated by a second time interval exceeds a first predetermined value a predetermined number of times within a first predetermined time period; in the process of judging the difference of the detected values ​​according to the second standard, the standard is deemed to have been exceeded only when the difference between the detected values ​​of two fluid pressures separated by a second time interval and / or the difference between the detected values ​​of two coolant pressures separated by a second time interval exceeds a second predetermined value a predetermined number of times within a second predetermined time period, wherein the first predetermined value is less than the second predetermined value.

[0013] Optionally, the first predetermined time period is less than or equal to the second predetermined time period.

[0014] Optionally, the judgment of the difference in the detection values ​​according to the first standard is completed in the cloud, and the judgment of the detection values ​​according to the second standard is completed on the vehicle.

[0015] Optionally, whether judging the difference of detected values ​​according to the first standard or the second standard, if the difference between the detected values ​​of two fluid pressures separated by a second time interval in the upstream pipeline of the cathode exceeds the standard, or if the difference between the detected values ​​of two fluid pressures separated by a second time interval in the downstream pipeline of the cathode exceeds the standard, it is considered that there is fluid leakage from the anode channel to the cathode channel inside the fuel cell stack; and / or, if the difference between the detected values ​​of two fluid pressures separated by a second time interval in the upstream pipeline of the coolant exceeds the standard, or if the difference between the detected values ​​of two fluid pressures separated by a second time interval in the downstream pipeline of the coolant exceeds the standard, it is determined that there is fluid leakage from the anode channel to the cooling chamber inside the fuel cell stack.

[0016] Optionally, the predetermined mode is during fuel cell startup or shutdown.

[0017] Optionally, the first predetermined time period and / or the second predetermined time period is less than or equal to the fuel cell stack startup time; or, the first predetermined time period and / or the second predetermined time period is less than or equal to the fuel cell stack shutdown time.

[0018] Optionally, the gas input to the anode of the fuel cell stack is hydrogen.

[0019] According to another aspect of this application, a method for identifying fluid leaks inside the stack of a fuel cell system is also provided, comprising:

[0020] The fuel cell stack is brought into a predetermined mode in which gas is introduced into the anode of the fuel cell stack while no gas is introduced into the cathode of the fuel cell stack.

[0021] Close the drain and vent valve between the downstream anode pipe and the downstream cathode pipe located outside the fuel cell stack;

[0022] Detecting the hydrogen content in the exhaust pipe of a fuel cell system.

[0023] The hydrogen content is tested simultaneously or sequentially using the first standard and the second standard to determine whether it exceeds the limit. The first standard is more stringent than the second standard. When the hydrogen content is determined to exceed the limit according to the first standard, an early warning is generated indicating that there is fluid leakage inside the fuel cell stack. When the hydrogen content is determined to exceed the limit according to the second standard, an instruction is generated to prevent the fuel cell stack from deflagration or reverse polarity, or an alarm is issued.

[0024] Optionally, in the process of judging hydrogen content according to the first standard, the standard is deemed exceeded only when the hydrogen content is greater than the first predetermined value a predetermined number of times within a first predetermined time period; in the process of judging hydrogen content according to the second standard, the standard is deemed exceeded only when the hydrogen content is greater than the second predetermined value a predetermined number of times within a second predetermined time period, wherein the first predetermined value is less than the second predetermined value.

[0025] Optionally, the first predetermined time period is less than or equal to the second predetermined time period.

[0026] Optionally, the determination of hydrogen content according to the first standard is completed in the cloud, while the determination of hydrogen content according to the second standard is completed at the vehicle end.

[0027] Optionally, the predetermined mode is during fuel cell startup or shutdown.

[0028] Optionally, the first predetermined time period and / or the second predetermined time period is less than or equal to the fuel cell stack startup time; or, the first predetermined time period and / or the second predetermined time period is less than or equal to the fuel cell stack shutdown time.

[0029] Optionally, the gas input to the anode of the fuel cell stack is hydrogen.

[0030] According to another aspect of this application, a method for early warning of whether the permeability of the proton exchange membrane in the fuel cell stack of a fuel cell vehicle exceeds the standard is also provided, comprising:

[0031] The fuel cell is brought into a predetermined mode in which gas is introduced into the anode of the fuel cell and a different gas is introduced into the cathode of the fuel cell.

[0032] The fluid pressure difference located outside the fuel cell stack and between the upstream and downstream anode lines or the upstream and downstream cathode lines is detected at specified time intervals.

[0033] Simultaneously or sequentially, the first and second standards are used to determine whether the corresponding fluid pressure difference exceeds the standard. The first standard is more stringent than the second standard. When the corresponding fluid pressure difference exceeds the standard according to the first standard, an early warning is generated indicating that the permeability of the proton exchange membrane has exceeded the standard. When the difference between the detected values ​​exceeds the standard according to the second standard, an instruction is generated to prevent the fuel cell stack from deflagration or reverse polarity, or an alarm is issued.

[0034] Optionally, in the process of judging the corresponding fluid pressure difference according to the first standard, the standard is deemed to be exceeded only when the corresponding fluid pressure difference is greater than the first predetermined value a predetermined number of times within a first predetermined time period; in the process of judging the corresponding fluid pressure difference according to the second standard, the standard is deemed to be exceeded only when the corresponding fluid pressure difference is greater than the second predetermined value a predetermined number of times within a second predetermined time period, wherein the first predetermined value is less than the second predetermined value.

[0035] Optionally, the first predetermined time period is less than or equal to the second predetermined time period.

[0036] Optionally, the determination of the corresponding fluid pressure difference according to the first standard is completed in the cloud, and the determination of the corresponding fluid pressure difference according to the second standard is completed at the vehicle end.

[0037] Optionally, the gas input to the anode of the fuel cell stack is hydrogen, and the gas input to the cathode of the fuel cell stack is air.

[0038] Optionally, the first predetermined time period and / or the second predetermined time period is less than or equal to the fuel cell stack startup time; or, the first predetermined time period and / or the second predetermined time period is less than or equal to the fuel cell stack shutdown time.

[0039] According to another aspect of this application, a system for early warning of fluid leakage inside the stack of a fuel cell system is also provided, the system comprising the fuel cell system and a cloud, wherein the electronic control unit of the fuel cell system and the cloud server in the cloud respectively execute the method according to the foregoing claims.

[0040] According to another aspect of this application, a computer program product is also provided, comprising a computer program or instructions, characterized in that the computer program or instructions, when executed by a processor, implement the aforementioned method.

[0041] By employing the technical means described in this application, early warning of fluid leakage inside the fuel cell stack can be provided without relying on dedicated hydrogen sensors, thereby improving the safe and reliable operation of the entire fuel cell system. Alternatively, the technical means described in this application can also serve as an important supplement to existing technologies that use hydrogen sensors to detect hydrogen leakage inside the fuel cell stack. Furthermore, the technical means described in this application can also be used to determine the permeability of the proton exchange membrane in the fuel cell stack and provide early warning, thus improving the safety diagnostic capabilities of the fuel cell system. Attached Figure Description

[0042] A more comprehensive understanding of the principles and aspects of this application will be gained from the detailed description below, in conjunction with the accompanying drawings. It should be noted that the scale of the drawings may vary for clarity, but this will not affect the understanding of this application. In the drawings:

[0043] Figure 1 This schematically illustrates a system block diagram for early warning of fluid leakage inside the stack of a fuel cell system according to an embodiment of this application.

[0044] Figure 2 An overall view of a fuel cell system according to one embodiment of this application is schematically shown;

[0045] Figure 3 The diagram schematically illustrates the plates in the stack of a fuel cell system;

[0046] Figure 4A This illustration shows a flowchart example of a method for detecting internal fluid leakage of a fuel cell system stack at a vehicle end according to an embodiment of this application;

[0047] Figure 4B The flowchart illustrates a method for providing early warning of potential fluid leaks inside the fuel cell stack of a fuel cell system via the cloud.

[0048] Figure 5 A schematic diagram of the internal structure of the fuel cell stack is shown.

[0049] Figure 6A and Figure 6BThe examples illustrate how the methods of this application are used to detect the fuel cell stack of a fuel cell vehicle to determine whether there is a fluid leak.

[0050] Figure 7 This illustration schematically shows another embodiment of the method according to this application, which involves inspecting the fuel cell stack of a fuel cell system in a fuel cell vehicle to determine whether a fluid leak is present; and

[0051] Figure 8A and 8B The flowcharts illustrate two methods: one for detecting abnormal permeability of the proton exchange membrane of a fuel cell system stack at the vehicle end, and the other for issuing an early warning of abnormal permeability of the proton exchange membrane of a fuel cell system stack in the cloud. Detailed Implementation

[0052] In the accompanying drawings of this application, features with the same structure or similar function are indicated by the same reference numerals.

[0053] Figure 1 This schematically illustrates a system block diagram for early warning of fluid leakage inside the stack of a fuel cell system according to one embodiment of this application. The early warning system mainly consists of a fuel cell system 100 and a cloud platform 800. See further... Figure 2 The fuel cell system 100 generally includes an electronic control unit 110, a fuel cell stack 200, and auxiliary systems. The electronic control unit 110 is configured to control the fuel cell stack 200 and auxiliary systems, for example, by sending operating commands to control the operation of the fuel cell stack 200 and / or auxiliary systems, or other corresponding components of the fuel cell system 100, such as solenoid valves, or to acquire operating parameters from the fuel cell stack 200 and / or auxiliary systems. The electronic control unit 110 may include a suitable type of computer and a memory. The memory stores a computer program product that has been programmed with part or all of the method examples or modifications described below, and is invoked and executed when needed. The cloud 800 may, for example, consist of a cloud server and a memory. The cloud's memory stores a computer program product that has been programmed with part or all of the method examples or modifications described below, and is invoked and executed by the cloud server when needed. For example, the electronic control unit 110 of the fuel cell system and the cloud 800 can communicate via any suitable wireless communication network using a suitable communication protocol.

[0054] Figure 2A simplified overall schematic diagram of a fuel cell system 100 according to one embodiment of this application is shown. In the context of this application, while the term "fuel cell system" primarily refers to a proton exchange membrane fuel cell system, other types of fuel cell systems, such as phosphoric acid fuel cell systems, may also be applied. As shown, the auxiliary systems of the fuel cell system 100 include, for example, a fuel subsystem 310, an air subsystem 320, a thermal management system 330, and a pressure monitoring subsystem. The fuel cell stack 200 is configured to convert the chemical energy in the supplied fuel (e.g., hydrogen) and oxidant (e.g., air) into electrical energy for output, for example, via a DC / DC converter shown in the figure. The auxiliary systems are configured to provide the necessary operating conditions for the electrochemical reactions of the fuel cell stack 200. For example, the fuel subsystem 310 and the air subsystem 320 may be configured to supply fuel (e.g., hydrogen) and oxidant (e.g., air) to the fuel cell stack 200, respectively. The thermal management system 330 includes, for example, radiators, pumps, filters, etc. (not shown), configured to utilize liquid coolant to conduct heat through the interior of the fuel cell stack 200 to dissipate and cool the heat generated during operation. A pressure monitoring subsystem is included, for example, in the piping that supplies fuel, air, and liquid coolant to the fuel cell stack 200 from the fuel subsystem 310, air subsystem 320, and thermal management system 330, to monitor changes in fluid pressure within the respective piping. Those skilled in the art will understand that, for simplicity, ... Figure 2 The document only shows those features necessary to illustrate the technical solution of this application. Figure 2 Other components of the fuel cell system not shown in the figure are not necessarily not essential to the technical solution of this application.

[0055] The fuel cell stack 200 generally comprises multiple battery cells stacked on top of each other along its thickness to form a stack. For example, these battery cells can be connected in series and / or in parallel as needed. Each battery cell includes an electrode (single or double electrode). Therefore, when multiple battery cells are stacked, a flow channel is defined between adjacent electrodes for the flow of liquid coolant to remove heat generated during operation of the fuel cell stack 200, ensuring proper cooling of the stack 200. Furthermore, each electrode is also formed with orifices through which fuel (e.g., hydrogen) and an oxidant (e.g., air) flow to conduct electrochemical reactions with a proton exchange membrane structure additionally disposed within the battery cell.

[0056] See also Figure 2Pipes 310A and 310B are provided between the fuel subsystem 310 and the fuel cell stack 200, particularly the anode of the fuel cell stack 200. Pipe 310A is configured to supply fuel gas (such as hydrogen) stored in the fuel subsystem 310 to the anode of the fuel cell stack 200, and pipe 310B is configured to discharge excess hydrogen (possibly containing moisture generated from the electrochemical reaction) from the fuel cell stack 200. Therefore, pipe 310A can be referred to as the upstream pipe of the anode, and pipe 310B can be referred to as the downstream pipe of the anode. Pipes 320A and 320B are provided between the air subsystem 320 and the fuel cell stack 200, particularly the cathode of the fuel cell stack 200. Pipeline 320A is configured to supply gaseous oxidant (e.g., air) provided by the air subsystem 320 into the cathode of the fuel cell stack 200, and pipeline 320B is configured to discharge excess air (possibly carrying moisture generated during the electrochemical reaction) from the fuel cell stack 200. Therefore, pipeline 320A can be referred to as the upstream cathode pipeline, and pipeline 320B as the downstream cathode pipeline. Pipelines 330A and 330B are provided between the thermal management system 330 and the fuel cell stack 200, particularly the cooling chamber of the fuel cell stack 200. Pipeline 330A is configured, for example, to supply coolant into the cooling chamber within the fuel cell stack 200, and pipeline 330B is configured to discharge coolant that flows through the cooling chamber and absorbs heat generated during the operation of the fuel cell stack 200 from the fuel cell stack 200. Therefore, pipeline 330A can be referred to as the upstream coolant pipeline, and pipeline 330B as the downstream coolant pipeline.

[0057] Furthermore, pipe 310B is connected to gas-liquid separator 610, allowing hydrogen gas containing moisture to be separated and directly reintroduced into the anode of fuel cell stack 200 via pipe 310A to participate in the electrochemical reaction. If too much water or excess hydrogen is stored in gas-liquid separator 610, drain and vent valve 620 needs to be opened to allow excess gas and liquid to be discharged through a dedicated pipe (e.g., a vehicle exhaust pipe) 500. Additionally, pipe 320B is connected to humidifier 630, allowing moisture-laden air to enter and humidify the air supplied via pipe 320A before being supplied to the cathode of fuel cell stack 200, which promotes the electrochemical reaction. As shown in the figure, drain and vent valve 631 can be opened when needed to allow excess gas and liquid to be discharged through dedicated pipe 500. The pressure monitoring subsystem may include, for example, pressure sensors 341A, 341B, 342A, 342B, 343A, and 343B. Pressure sensors 341A and 341B may be respectively installed upstream of the inlet and downstream of the outlet of the internal channel of the anode in pipelines 310A and 310B, respectively, to monitor changes in the fluid pressure flowing within these pipelines. Pressure sensors 342A and 342B may be respectively installed upstream of the inlet and downstream of the outlet of the internal channel of the cathode in pipelines 320A and 320B, respectively, to monitor changes in the fluid pressure flowing within these pipelines. Pressure sensors 343A and 343B may be respectively installed upstream of the inlet and downstream of the outlet of the coolant channel in pipelines 330A and 330B, respectively, to monitor changes in the fluid pressure flowing within these pipelines.

[0058] In the stack 200, the flow channels between the plates (e.g., biplates) of the stacked battery cells form the cooling chamber of the stack 200, and the orifices that are aligned with each other form channels for fuel and oxidant to enter and exit and communicate with pipes 310A, 310B and 320A, 320B. Figure 3A schematic diagram illustrates one (single or dual) electrode 210 in a cell of a fuel cell system. For example, multiple flow channels 210a are shown formed in the middle region of the electrode 210, which constitute portions of the stack 200 communicating with conduits 310A and 310B. Orifices are shown formed near both sides of the electrode 210. When multiple electrode plates 210 are stacked on top of each other in the thickness direction, these orifices located near both sides respectively form portions of the stack 200 communicating with conduits 320A, 320B and 330A, 330B, for the entry and exit of coolant, fuel, and oxidant into and out of the cell. For example, orifice 210b forms a portion for the passage of coolant into the battery cell, orifice 210c forms a portion for the passage of coolant out of the battery cell, and orifices 210b and 210c are in fluid communication with flow channel 210a; orifice 210d forms a portion for the passage of air into the battery cell, and orifice 210e forms a portion for the passage of air out of the battery cell.

[0059] Inside the fuel cell stack 200, the channels through which the coolant, fuel, and oxidizer flow should be sealed and isolated from each other. However, due to unforeseen reasons during the operation of the fuel cell stack 200, a leak occurred in the sealing structure used to achieve isolation inside the stack 200, causing hydrogen to accidentally leak into the channels used for coolant and / or oxidizer. Figure 3 In the diagram, arrow 1 indicates the possibility of hydrogen leaking from its flow path into orifice 210c, which is used for coolant exit from the battery cell; arrow 2 indicates the possibility of hydrogen leaking from its flow path into orifice 210e, which is used for air exit from the battery cell; arrow 3 indicates the possibility of hydrogen leaking from its flow path into orifice 210b, which is used for coolant entry into the battery cell; and arrow 4 indicates the possibility of hydrogen leaking from its flow path into orifice 210d, which is used for air entry into the battery cell.

[0060] In existing technologies, to determine whether a hydrogen leak exists, a hydrogen sensor must be added to the fuel cell stack. This increases the complexity of the fuel cell system and also suffers from the drawback of low reliability if the hydrogen leak is determined solely by the detection structure of the hydrogen sensor. The inventors of this application conceived of utilizing the existing pressure monitoring subsystem in the fuel cell system to monitor and analyze pressure fluctuations in the pipeline to determine whether a hydrogen leak exists inside the fuel cell stack 200.

[0061] During startup or shutdown of the fuel cell stack, air, serving as the oxidant, is not input to the cathode of the fuel cell stack 200 via the upstream cathode pipe 320A. Only hydrogen, serving as fuel, is input to the anode of the fuel cell stack 200 via the upstream anode pipe 310A. Therefore, if a fluid leak exists inside the fuel cell stack 200, the hydrogen input to the anode of the fuel cell stack 200 will leak through the leak point into the channels through which the oxidant and / or coolant flows inside the fuel cell stack 200, thereby causing changes in the fluid pressure in the upstream cathode pipe 320A and / or the downstream cathode pipe 320B and / or the upstream coolant pipe 330A and / or the downstream coolant pipe 330B. Therefore, the main idea of ​​this application for detecting fluid leaks inside the fuel cell stack is: under the premise that there is no gas input to the cathode of the fuel cell stack but there is a gas input such as hydrogen to the anode of the fuel cell stack, the fluid pressure changes in these pipes outside the fuel cell stack that communicate with the anode and / or cooling chamber of the fuel cell stack are judged to determine whether there is a fluid leak inside the fuel cell stack. Furthermore, and more importantly, this application not only detects fluid leaks inside the fuel cell stack, but also provides early warnings based on cloud-based big data analysis before fluid leaks inside the fuel cell stack reach a level that affects the safe operation of the fuel cell stack.

[0062] According to one embodiment of this application, during the operation of the fuel cell system 100, whenever the stack is started or stopped, or whenever the stack reaches a mode in which only the anode of the stack receives a gas such as hydrogen, while the cathode of the stack receives no gas, the electronic control unit 110 of the fuel cell system 100 can determine whether there is a leak in the internal channels of the stack 200 by monitoring the fluid pressure changes in the pipelines 320A, 320B, 330A, and 330B; at the same time, the detected fluid pressure changes are synchronously transmitted to the cloud 800 via a wireless network for synchronous analysis. In other words, if the vehicle where the electronic control unit 110 is located is considered the vehicle end, according to the embodiments of this application, the fluid leakage detection and analysis inside the fuel cell stack at the vehicle end and the fluid leakage detection and analysis inside the fuel cell stack in the cloud are performed simultaneously. However, when judging whether the fluid pressure change in the pipeline exceeds the standard, the detection and judgment standard adopted by the cloud is more stringent than that at the vehicle end. In this way, the cloud will always make a detection result that there is already a fluid leak inside the fuel cell stack before the vehicle end. Thus, the detection result completed by the cloud can serve as an early warning of fluid leakage inside the fuel cell stack, and can be used as an early notification to the driver of the vehicle or the vehicle's repair shop, etc., as a maintenance or repair reminder. Furthermore, if the vehicle end makes a detection result that there is already a fluid leak inside the fuel cell stack, it can, for example, force the fuel cell stack to not start or issue a buzzer alarm to the driver in the cockpit. In this way, according to the embodiments of this application, the dual detection at the cloud and vehicle end greatly increases the safety of the fuel cell system or its fuel cell stack operation.

[0063] Figure 4AThe flowchart illustrates an example of a method for detecting whether there is a fluid leak inside the stack 200 of a fuel cell system 100 at a vehicle end, according to an embodiment of this application. Figure 4B The flowchart illustrates a method for providing early warning of fluid leakage within the fuel cell stack 200 of the fuel cell system 100 in the cloud (or utilizing cloud-based big data processing). The methods or method steps described in this application, or modifications thereof, can be stored as a computer program product and executed when needed by the central processing unit or electronic control unit of the fuel cell system 100 or a cloud server.

[0064] Figure 5 A simplified model of the interior of the fuel cell stack 200 is schematically shown. As shown, the interior of the fuel cell stack 200 includes an internal channel 2100 for defining the anode of the fuel cell stack 200, an internal channel 2200 for defining the cathode of the fuel cell stack 200, and an internal channel 2300 for defining the flow of coolant through the fuel cell stack 200.

[0065] In step S5, the electronic control unit 110 of the fuel cell system 100 begins to detect whether there is a fluid leak inside the fuel cell stack 200.

[0066] In step S10, it is first determined whether the fuel cell stack 200 of the fuel cell system 100 has entered a predetermined mode. For example, in an embodiment of this application, such a predetermined mode means that gas (e.g., hydrogen) is input into the anode of the fuel cell stack 200 via the upstream anode line 310A, while no gas is input into the cathode of the fuel cell stack 200 via the upstream cathode line 320A.

[0067] If the result of step S10 is "yes", then proceed to step S20; otherwise, continue waiting. In step S20, a counter N is set to 0. For example, the counter N here can be a computer register or a variable in the running program. In the context of this application, register and variable can be understood interchangeably.

[0068] In step S30, the fluid pressure in the upstream cathode pipe 320A and / or downstream cathode pipe 320B and / or upstream coolant pipe 330A and / or downstream coolant pipe 330B is detected and the pressure value is determined using the corresponding pressure sensors of the pressure monitoring subsystem. For example, the detected pressure value can be stored in variable P1. Figure 2For example, when hydrogen gas is blown into the anode of the fuel cell stack 200 via pipe 310A, the pressure value of the fluid in pipes 320A and / or 320B is detected by sensors 342A and / or 342B, and the detected pressure value is stored in variable P1. Alternatively or additionally, when hydrogen gas is blown into the anode of the fuel cell stack 200 via pipe 310A, the pressure value of the fluid in pipes 330A and / or 330B is detected by sensors 343A and / or 343B, and the detected pressure value is stored in variable P1.

[0069] In step S40, a certain delay is waited, such as a few milliseconds, a few seconds, or a few minutes. Then, in step S50, the fluid pressure in the corresponding pipeline is detected using the same pressure sensor used in step S30, and the detected pressure value is stored in variable P2. In step S60, the difference ΔP or the absolute value of the difference |ΔP| between variables P2 and P1 is calculated.

[0070] In step S70, it is determined whether the difference ΔP or the absolute value of the difference |ΔP| is greater than a predetermined value C1. If the determination result is "no", then in step S90, the counter N = N-1, and the process proceeds to step S100, where the value of variable P1 is changed to the value of variable P2. If the determination result of step S70 is "yes", then in step S80, the counter N = N+1. Then, in step S110, it is determined whether the counter N is greater than a predetermined integer value a. If the determination result is "no", the process proceeds to step S100; if the determination result is "yes", the process proceeds to step S120. In step S120, an alarm message is issued, for example, by displaying an alarm on a monitor or by emitting an audible alarm using a buzzer. Simultaneously, without affecting the safe driving of the vehicle, the fuel cell stack 200 can be forcibly prevented from starting, thereby ensuring the safety of the vehicle or its occupants. The alarm message can be received and processed by a computer other than the central processing unit. In the context of this application, variables P1 and P2 do not necessarily refer to a single variable, but can also refer to a group of variables to store a single value or a set of values. Therefore, the difference ΔP or the absolute value of the difference |ΔP| can also refer to a single value or a set of values.

[0071] According to one embodiment of this application, the determination of counter N between step S20 and step S110 can be completed within a predetermined time period, such as a second predetermined time period. For example, the second predetermined time period can be less than or equal to the time period of the fuel cell stack startup or shutdown process. This is performed at the vehicle end. Figure 4AIn the process of the method shown, especially in step S60, the difference ΔP or the absolute value of the difference |ΔP| can be transmitted via a wireless network, for example by the electronic control unit 110, to the cloud server of the cloud 800 for processing.

[0072] like Figure 4B As shown, in step S61, a counter M is set to 0. In step S62, the cloud server of cloud 800 obtains the difference ΔP or the absolute value of the difference |ΔP| transmitted from the vehicle and stores it accordingly for subsequent judgment. In step S71, it is determined whether the difference ΔP or the absolute value of the difference |ΔP| obtained in step S62 (e.g., the latest) is greater than a predetermined value C2, where the predetermined value C2 < the predetermined value C1. If the judgment result is "no", then in step S91, the counter M = M-1, and the process returns to step S62 to continue obtaining the transmitted difference ΔP or the absolute value of the difference |ΔP| from the vehicle and storing it accordingly for subsequent judgment. If the judgment result in step S71 is "yes", then in step S81, the counter M = M+1. Then, in step S111, it is determined whether the counter M is greater than a predetermined integer value b. If the judgment result is "no", the process returns to step S62; if the judgment result is "yes", the process returns to step S121.

[0073] According to one embodiment of this application, the determination of counter M between step S61 and step S111 can be completed within a predetermined time period, such as a first predetermined time period. For example, the first predetermined time period can be less than or equal to the time period of the fuel cell startup or shutdown process. According to a preferred embodiment of this application, the first predetermined time period can be less than or equal to a second predetermined time period.

[0074] In an alternative embodiment, if all detected pressure values ​​have been acquired or according to a pre-set condition, the time interval between two detected pressure values ​​selected for solving the difference ΔP or the absolute value of the difference |ΔP| can be greater than or equal to the delay time set in step S40.

[0075] According to an embodiment of this application, the predetermined value C2 and the predetermined integer value b are set such that although fluid leakage occurs inside the fuel cell stack 200, the extent of such leakage will not cause a deflagration of the fuel cell stack 200 or a serious safety event such as reverse polarity. Therefore, in step S121, the cloud server of the cloud 800 can send a message that fluid leakage has occurred inside the fuel cell stack to the driver of the car or the car repair shop via a wireless communication network, so as to prepare for maintenance in advance.

[0076] In such Figure 4AIn steps S70 and S110, the predetermined value C1 and the predetermined integer value a are set such that the fluid leakage inside the fuel cell stack 200 is sufficient to cause a deflagration or reverse polarity incident in the fuel cell stack 200. Therefore, in step S120, the fuel cell stack 200 is forcibly prevented from starting, thereby ensuring the safety of the vehicle or its occupants. According to embodiments of this application, the detection and judgment at the vehicle end and the detection and judgment at the cloud end can be performed synchronously or asynchronously. For example, during the asynchronous process, such as... Figure 4B The step S62 shown is replaced by reading the difference ΔP or the absolute value of the difference |ΔP| from the data already stored in the cloud's memory, and as... Figure 4B The execution of steps S71, S81, S91, S111, and S121 shown can occur at any point in the entire lifespan of the fuel cell stack.

[0077] Figure 6A and Figure 6B This illustration schematically shows the application of the method of this application (e.g.) Figure 4A The illustrated embodiment detects the fuel cell stack of a fuel cell vehicle to determine if fluid leakage is present. The statistical data is the difference in pressure between the air outside the stack and the fluid pressure in the pipeline through which the coolant flows during the fuel cell stack detection process (at the vehicle end). (The delay time in step S40 is set to 2 seconds, and the integer value 'a' in step S110 is set to 2.) Figure 6A The diagram shows the fluid pressure changes in various pipelines of the fuel cell system when there is no fluid leakage inside the stack. Circles 1 and 2 represent the pressure differences in the pipelines flowing through air and coolant, respectively. Figure 6B The diagram shows the fluid pressure changes in various pipelines of the fuel cell system when there is a fluid leak inside the stack. Circle 3 represents the pressure difference change in the pipeline flowing through the air. It can be seen that... Figure 6A In the middle, the difference in fluid pressure between circles 1 and 2 changes relatively smoothly and does not exceed the predetermined value (i.e., the judgment result of step S70 is "no"); in Figure 6B In the process, the pressure difference in circle 3 changes drastically and exceeds a predetermined value (i.e., the judgment result of step S70 is "yes"). Therefore, it can be concluded that there is a fluid leak inside the fuel cell stack, especially a leak from the internal channel of the anode towards the internal channel of the cathode, thus issuing a warning.

[0078] According to another embodiment of this application, for example, a hydrogen sensor 510 is installed in the exhaust gas line 500. When the drain and exhaust valve 620 is closed, during the startup or shutdown of the fuel cell stack (i.e., when air as an oxidant is prohibited from entering the stack cathode and only hydrogen as fuel is input to the stack anode), if the hydrogen sensor 510 detects that the hydrogen content in the exhaust gas line 500 exceeds the limit, it can be considered that there is a leak inside the fuel cell stack 200 from the internal channel flowing through the fuel (e.g., hydrogen) to the internal channel flowing through the oxidant (e.g., air). This is because if there is no leak in the internal channel of the fuel cell stack 200 when the drain and exhaust valve 620 is closed, the hydrogen supplied to the anode of the fuel cell stack 200 via line 310A should return to the fuel subsystem 310 via line 310B. Thus, the fluid pressure in lines 320A and / or 320B should remain substantially stable. The process of detecting the hydrogen content in the exhaust gas line 500 using the hydrogen sensor 510 can also be referred to as follows: Figure 4A and 4B The method is implemented as shown. For example, in this case, in steps S30 and S50, variables P1 and P2 can be considered to store the hydrogen concentration detected by the hydrogen sensor 510, while in step S60, the difference ΔP or the absolute value of the difference |ΔP| is the difference or the absolute value of the difference in hydrogen concentration.

[0079] Figure 7 This illustration schematically depicts another embodiment of the method according to this application, detecting the fuel cell stack of a fuel cell system in a fuel cell vehicle to determine the presence of fluid leakage. This is achieved by utilizing a hydrogen sensor 510 installed in the exhaust pipe 500, and detecting the hydrogen content in the exhaust pipe 500 in anode purge mode with the drain / vent valve 620 closed. Figure 7 In curve 1, points A and B represent the measured flow rate and quality of hydrogen gas input to the anode of the fuel cell stack, while points C and D in curve 2 represent the hydrogen concentration in the exhaust gas line 500 (detected by the hydrogen sensor 510). In practice, points A and C correspond, and points B and D correspond. A comparison reveals a significant difference between points C and D when the flow rate and quality of hydrogen gas input to the anode of the fuel cell stack remain relatively constant. This demonstrates that the above method embodiment can be used to determine whether fluid leakage exists inside the fuel cell stack.

[0080] In addition to identifying and issuing early warnings for fluid leaks within the fuel cell stack 200, the modified method of this application can also be used to determine whether the permeability of the proton exchange membrane within the fuel cell stack 200 is abnormal and to issue early warnings based on cloud-based big data. The process for detecting the permeability of the proton exchange membrane and the early warning based on cloud-based big data can be referred to as follows: Figure 4A and 4B Implemented by the method shown or a modification of the method. Figure 8A and 8B The flowcharts illustrate, respectively, a method for detecting whether the permeability of the proton exchange membrane of the fuel cell stack 200 of the fuel cell system 100 is abnormal at the vehicle end and a method for issuing an early warning on the cloud for whether the permeability of the proton exchange membrane of the fuel cell stack 200 of the fuel cell system 100 is abnormal.

[0081] In step S5′, the electronic control unit 110 of the fuel cell system 100 begins to detect whether there is an abnormality in the permeability of the proton exchange membrane of the fuel cell stack 200.

[0082] In step S10′, it is first determined whether the fuel cell stack 200 of the fuel cell system 100 has entered a predetermined mode. For example, in the embodiments of this application, such a predetermined mode means that hydrogen as fuel and air as oxidant have been simultaneously input into the anode and cathode of the fuel cell stack 200.

[0083] If the judgment result of step S10′ is "yes", then proceed to step S20; otherwise, continue waiting. In step S20, a counter N is set to 0. For example, the counter N here can be a computer register or a variable in the running program. In the context of this application, register and variable can be understood interchangeably.

[0084] In step S30', the pressure difference between the upstream anode pipe 310A and the downstream anode pipe 310B, or between the upstream anode pipe 310A and the upstream cathode pipe 320A, or between the upstream anode pipe 310A and the downstream cathode pipe 320B, is detected and recorded using the corresponding pressure sensors of the pressure monitoring subsystem. In step S40', it is determined whether the pressure difference obtained in step S30' is greater than a predetermined value D1. If the determination result is "no", then in step S60', the counter N = N-1, and the process returns to step S30', continuing to detect and record the pressure difference between the upstream anode pipe 310A and the downstream anode pipe 310B, or between the upstream anode pipe 310A and the upstream cathode pipe 320A, or between the upstream anode pipe 310A and the downstream cathode pipe 320B, using the corresponding pressure sensors of the pressure monitoring subsystem. For example, a predetermined time interval can be waited before detection and recording.

[0085] If the result of the judgment in step S40' is "yes", then in step S50', the counter N = N + 1. Then, in step S70', it is determined whether the counter N is greater than a predetermined integer value c. If the result is "no", then proceed to step S30'; if the result is "yes", then proceed to step S80'. In step S80', an alarm message is issued, for example, by displaying an alarm on a monitor or by emitting an audible alert using a buzzer. Simultaneously, without affecting safe driving, the fuel cell stack 200 can be forcibly prevented from starting, thereby ensuring the safety of the vehicle or its occupants. The alarm message can be received and processed by a computer other than the central processing unit.

[0086] According to an embodiment of this application, in step S30′, the pressure difference between the upstream pipeline 310A and the downstream pipeline 310B of the anode, or the pressure difference between the upstream pipeline 310A or the downstream pipeline 310B of the anode and the upstream pipeline 320A of the cathode, or the pressure difference between the upstream pipeline 310A or the downstream pipeline 310B of the anode and the downstream pipeline 320B of the cathode, is detected and recorded by the corresponding pressure sensor of the pressure monitoring subsystem. At the same time, the pressure difference is synchronously transmitted to the cloud via a wireless network and stored accordingly.

[0087] like Figure 8B As shown, in step S61', a counter M is set to 0. In step S62', the cloud server of cloud 800 obtains the pressure difference transmitted from the vehicle (e.g., the pressure difference obtained in step S30') or reads a data point from the pre-stored pressure difference data in the memory of cloud 800. In step S71', it is determined whether the pressure difference obtained in step S62' (e.g., the latest) is greater than a predetermined value D2, where the predetermined value D2 < the predetermined value D1. If the determination result is "no", then in step S91', the counter M = M-1, and the process proceeds to step S62' to continue obtaining the transmitted pressure difference from the vehicle or reading the next data point from the pre-stored pressure difference data in the memory of cloud 800. If the determination result in step S71' is "yes", then in step S81', the counter M = M+1. Then, in step S111, it is determined whether the counter M is greater than a predetermined integer value d. If the result of the judgment is "no", then proceed to step S62'; if the result of the judgment is "yes", then proceed to step S121'. In step S121', the cloud server of cloud 800 can send a message that the permeability of the proton exchange membrane in the fuel cell stack 200 is abnormal to the car driver or car repair shop via the wireless communication network, so as to prepare for maintenance in advance.

[0088] According to embodiments of this application, when determining whether the permeability of the proton exchange membrane within the fuel cell stack 200 is abnormal, for example, the selection of a predetermined value D2 and an integer value d is equivalent to the selection of a predetermined value D1 and an integer value 1, making the detection and judgment standards adopted by the cloud end more stringent than those of the vehicle end. Thus, the cloud end will always detect abnormalities in the permeability of the proton exchange membrane within the fuel cell stack 200 before the vehicle end. Therefore, the detection results completed by the cloud end can serve as an early warning of proton exchange membrane abnormalities in the fuel cell stack, and can be used as a preliminary notification to the driver or repair shop of the vehicle for inspection or maintenance. Furthermore, if the vehicle end detects an abnormality in the proton exchange membrane of the fuel cell stack, it can, for example, force the fuel cell stack to fail to start or issue a buzzer alarm to the driver in the cockpit. Thus, according to embodiments of this application, dual detection by the cloud end and the vehicle end greatly increases the safety of the fuel cell system or its fuel cell stack operation.

[0089] Although specific embodiments of this application are described in detail herein, they are provided for illustrative purposes only and should not be construed as limiting the scope of this application. Furthermore, those skilled in the art will understand that the various embodiments described herein can be used in combination with each other. Various substitutions, modifications, and alterations can be conceived without departing from the spirit and scope of this application.

Claims

1. A method for early warning of fluid leakage inside the stack of a fuel cell system, comprising: The fuel cell stack is brought into a predetermined mode in which gas is introduced into the anode of the fuel cell stack while no gas is introduced into the cathode of the fuel cell stack. The fluid pressure in the pipeline located outside the fuel cell stack and connected to the cathode of the fuel cell stack and / or the coolant pressure in the pipeline connected to the cooling chamber inside the fuel cell stack are detected at a predetermined first time interval. as well as Simultaneously or sequentially, the difference between two fluid pressure detection values ​​separated by a second time interval is determined using a first standard and a second standard to determine whether the difference between two coolant pressure detection values ​​separated by a second time interval exceeds the standard, wherein the second time interval is greater than or equal to the first time interval, and wherein the first standard is more stringent than the second standard. When the difference between the detection values ​​exceeds the standard according to the first standard, an early warning of fluid leakage inside the fuel cell stack is generated, and when the difference between the detection values ​​exceeds the standard according to the second standard, an instruction is generated to prevent the fuel cell stack from deflagration or reverse polarity, or an alarm is issued.

2. The method according to claim 1, characterized in that, In the process of judging the difference of the detected values ​​according to the first standard, it is determined that the standard is exceeded only when the difference between the detected values ​​of two fluid pressures separated by a second time interval and / or the difference between the detected values ​​of two coolant pressures separated by a second time interval exceeds the first predetermined value a predetermined number of times within the first predetermined time period; in the process of judging the difference of the detected values ​​according to the second standard, it is determined that the standard is exceeded only when the difference between the detected values ​​of two fluid pressures separated by a second time interval and / or the difference between the detected values ​​of two coolant pressures separated by a second time interval exceeds the second predetermined value a predetermined number of times within the second predetermined time period, wherein the first predetermined value is less than the second predetermined value.

3. The method according to claim 2, characterized in that, The first predetermined time period is less than or equal to the second predetermined time period.

4. The method according to claim 3, characterized in that, The judgment of the difference in the detection values ​​according to the first standard is completed in the cloud, while the judgment of the detection values ​​according to the second standard is completed at the vehicle end.

5. The method according to claim 4, characterized in that, Whether judging the difference of detected values ​​according to the first standard or the second standard, if the difference between the detected values ​​of two fluid pressures separated by a second time interval in the upstream pipeline of the cathode exceeds the standard, or if the difference between the detected values ​​of two fluid pressures separated by a second time interval in the downstream pipeline of the cathode exceeds the standard, it is considered that there is fluid leakage from the anode channel to the cathode channel inside the fuel cell stack; and / or, if the difference between the detected values ​​of two fluid pressures separated by a second time interval in the upstream pipeline of the coolant exceeds the standard, or if the difference between the detected values ​​of two fluid pressures separated by a second time interval in the downstream pipeline of the coolant exceeds the standard, it is determined that there is fluid leakage from the anode channel to the cooling chamber inside the fuel cell stack.

6. The method according to any one of claims 2 to 5, characterized in that, The predetermined mode is during fuel cell startup or shutdown.

7. The method according to claim 6, characterized in that, The first predetermined time period and / or the second predetermined time period are less than or equal to the fuel cell stack startup time; or, the first predetermined time period and / or the second predetermined time period are less than or equal to the fuel cell stack shutdown time.

8. The method according to claim 7, characterized in that, The gas fed into the anode of the fuel cell stack is hydrogen.

9. A method for identifying fluid leaks inside the stack of a fuel cell system, comprising: The fuel cell stack is brought into a predetermined mode in which gas is introduced into the anode of the fuel cell stack while no gas is introduced into the cathode of the fuel cell stack. Close the drain and vent valve between the downstream anode pipe and the downstream cathode pipe located outside the fuel cell stack; Detecting the hydrogen content in the exhaust pipe of a fuel cell system. The hydrogen content is tested simultaneously or sequentially using the first standard and the second standard to determine whether it exceeds the limit. The first standard is more stringent than the second standard. When the hydrogen content is determined to exceed the limit according to the first standard, an early warning is generated indicating that there is fluid leakage inside the fuel cell stack. When the hydrogen content is determined to exceed the limit according to the second standard, an instruction is generated to prevent the fuel cell stack from deflagration or reverse polarity, or an alarm is issued.

10. The method according to claim 9, characterized in that, In the process of judging hydrogen content according to the first standard, it is considered to exceed the standard only when the hydrogen content is greater than the first predetermined value a predetermined number of times within the first predetermined time period; in the process of judging hydrogen content according to the second standard, it is considered to exceed the standard only when the hydrogen content is greater than the second predetermined value a predetermined number of times within the second predetermined time period, wherein the first predetermined value is less than the second predetermined value.

11. The method according to claim 10, characterized in that, The first predetermined time period is less than or equal to the second predetermined time period.

12. The method according to claim 11, characterized in that, The determination of hydrogen content based on the first standard is completed in the cloud, while the determination of hydrogen content based on the second standard is completed at the vehicle end.

13. The method according to any one of claims 10 to 12, characterized in that, The predetermined mode is during fuel cell startup or shutdown.

14. The method according to claim 13, characterized in that, The first predetermined time period and / or the second predetermined time period are less than or equal to the fuel cell stack startup time; or, the first predetermined time period and / or the second predetermined time period are less than or equal to the fuel cell stack shutdown time.

15. The method according to claim 14, characterized in that, The gas fed into the anode of the fuel cell stack is hydrogen.

16. A method for early warning of whether the permeability of the proton exchange membrane in a fuel cell vehicle stack exceeds the standard, comprising: The fuel cell is brought into a predetermined mode in which gas is introduced into the anode of the fuel cell and a different gas is introduced into the cathode of the fuel cell. The fluid pressure difference located outside the fuel cell stack and between the upstream pipeline of the anode and the anode pipeline, or between the upstream or downstream pipeline of the anode and the upstream or downstream pipeline of the cathode, is detected at specified time intervals. as well as Simultaneously or sequentially, the first and second standards are used to determine whether the corresponding fluid pressure difference exceeds the standard. The first standard is more stringent than the second standard. When the corresponding fluid pressure difference exceeds the standard according to the first standard, an early warning is generated indicating that the permeability of the proton exchange membrane has exceeded the standard. When the difference between the detected values ​​exceeds the standard according to the second standard, an instruction is generated to prevent the fuel cell stack from deflagration or reverse polarity, or an alarm is issued.

17. The method according to claim 16, characterized in that, In the process of judging the corresponding fluid pressure difference according to the first standard, it is determined that the standard is exceeded only when the corresponding fluid pressure difference is greater than the first predetermined value a predetermined number of times within the first predetermined time period; in the process of judging the corresponding fluid pressure difference according to the second standard, it is determined that the standard is exceeded only when the corresponding fluid pressure difference is greater than the second predetermined value a predetermined number of times within the second predetermined time period, wherein the first predetermined value is less than the second predetermined value.

18. The method according to claim 17, characterized in that, The first predetermined time period is less than or equal to the second predetermined time period.

19. The method according to claim 18, characterized in that, The determination of the corresponding fluid pressure difference according to the first standard is completed in the cloud, while the determination of the corresponding fluid pressure difference according to the second standard is completed at the vehicle end.

20. The method according to claim 19, characterized in that, The gas fed into the anode of the fuel cell stack is hydrogen, and the gas fed into the cathode of the fuel cell stack is air.

21. The method according to claim 20, characterized in that, The first predetermined time period and / or the second predetermined time period are less than or equal to the fuel cell stack startup time; or, the first predetermined time period and / or the second predetermined time period are less than or equal to the fuel cell stack shutdown time.

22. A system for early warning of fluid leakage inside the stack of a fuel cell system, the system comprising the fuel cell system and a cloud, wherein an electronic control unit of the fuel cell system and a cloud server in the cloud respectively execute the method according to claims 1 to 21.

23. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or instructions are executed by a processor, they implement the method as described in claims 1 to 22.

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