Method and system for detecting hydrogen leakage of fuel cell of electric vehicle

Abstract

A method for detecting hydrogen leakage of a fuel cell of an electric vehicle comprises the steps that the current SOC of a power battery pack of the electric vehicle and the current motion state of the electric vehicle are detected so as to judge whether power supply of the fuel cell of the electric vehicle is stopped or not at present and estimate the duration of power supply stopping of the fuel cell in the current motion state of the electric vehicle, wherein the current motion state of the electric vehicle comprises the current vehicle speed; and if the estimated duration reaches a predetermined duration threshold, inputting hydrogen to the anode of the fuel cell to maintain the gas pressure within the anode at a constant value while detecting the gas pressure within the cathode of the fuel cell and calculating a rate of rise of the gas pressure within the cathode, and if the rising rate is greater than or equal to a preset rising rate threshold value, judging that hydrogen in the fuel cell leaks from the anode to the cathode. Also proposed is a system for detecting a hydrogen leak of a fuel cell of an electric vehicle, the system being configured to perform the method according to the invention.

Description

Technical Field

[0001] This invention relates to the field of fuel cells. Specifically, it relates to a method and system for detecting hydrogen leakage in the fuel cells of electric vehicles. Background Technology

[0002] Hydrogen fuel cells are widely used in electric vehicles. Because electric vehicle fuel cells are typically placed in high-temperature environments, such as within compartments, and surrounded by numerous components, the presence of hydrogen at high temperatures could cause a fire or even an explosion if hydrogen leaks from the anode of the fuel cell stack. Furthermore, if the fuel cell ages internally, such as due to deterioration or leaks in the proton exchange membrane, hydrogen may leak internally from the anode to the cathode, instead of ionizing at the anode and transferring to the cathode via the proton exchange membrane as expected. In the event of internal hydrogen leakage to the cathode, it may further escape through the exhaust pipe, leading to a decrease in reaction efficiency at the stack and posing a potential hazard.

[0003] To detect hydrogen leaks in the fuel cells of electric vehicles, existing technologies typically involve placing sensors to monitor hydrogen concentration in the compartment housing the fuel cell and in the exhaust pipe, issuing an alarm signal when the hydrogen concentration reaches a certain threshold. However, this approach places demands on the installation location, accuracy, and reliability of the hydrogen concentration monitoring sensors. Furthermore, meeting these requirements and ensuring safety usually necessitates the placement of additional components, thereby increasing the size and cost of the fuel cell.

[0004] Therefore, there is a need for a method and system for detecting hydrogen leaks in the fuel cells of electric vehicles, which should overcome the aforementioned shortcomings of the prior art. Summary of the Invention

[0005] This invention proposes a method for detecting hydrogen leakage in the fuel cell of an electric vehicle, comprising:

[0006] The system detects the current State of Charge (SOC) of the electric vehicle's battery pack and the vehicle's current state of motion to determine whether the fuel cell is currently shutting down and to estimate the duration of this shutdown under the current vehicle's motion state. The current motion state includes the vehicle's current speed.

[0007] If the estimated duration reaches a predetermined duration threshold, hydrogen is introduced into the anode of the fuel cell to maintain the gas pressure inside the anode at a constant value. At the same time, the gas pressure inside the cathode of the fuel cell is detected and the rate of increase of the gas pressure inside the cathode is calculated. If the rate of increase is greater than or equal to a predetermined rate of increase threshold, it is determined that there is an internal leakage of hydrogen from the anode to the cathode in the fuel cell.

[0008] The method may further include: when the gas pressure in the cathode rises to the point that the gas pressure in the anode is the same as the gas pressure in the cathode, stopping the input of hydrogen to the anode, detecting the gas pressure in the anode and calculating the rate of decrease of the gas pressure in the anode, and if the rate of decrease is greater than or equal to a predetermined rate of decrease threshold, determining that there is an external leakage of hydrogen from the anode to the external environment in the fuel cell.

[0009] The present invention also proposes a system for detecting hydrogen leakage in the fuel cell of an electric vehicle, comprising:

[0010] The controller is configured to detect the current state of charge (SOC) of the battery pack of the electric vehicle and the current state of motion of the electric vehicle to determine whether the fuel cell of the electric vehicle is currently shut down and to estimate the duration of the shutdown of the fuel cell in the current state of motion of the electric vehicle, wherein the current state of motion of the electric vehicle includes the current vehicle speed.

[0011] A hydrogen injection valve is configured to supply hydrogen to the anode of the fuel cell to maintain the gas pressure within the anode at a constant value when the duration estimated by the controller reaches a predetermined duration threshold.

[0012] An anode gas pressure sensor configured to sense the gas pressure within the anode and a cathode gas pressure sensor configured to sense the gas pressure within the cathode of the fuel cell.

[0013] The controller is further configured to calculate the rate of increase of the gas pressure in the cathode while maintaining the gas pressure in the anode at a constant value. If the rate of increase is greater than or equal to a predetermined rate of increase threshold, it is determined that there is an internal leakage of hydrogen from the anode to the cathode in the fuel cell.

[0014] When the gas pressure in the cathode rises to the point that the gas pressure in the anode becomes the same as the gas pressure in the cathode, the hydrogen injection valve is further configured to stop supplying hydrogen to the anode, and the controller is further configured to calculate the rate of decrease of the gas pressure in the anode based on the gas pressure in the anode sensed by the anode gas pressure sensor, and if the rate of decrease is greater than or equal to a predetermined rate of decrease threshold, it is determined that there is an external leakage of hydrogen from the anode to the external environment in the fuel cell.

[0015] The present invention also proposes a computer program product comprising computer instructions that, when executed by a processor, implement the method according to the present invention. Attached Figure Description

[0016] Figure 1 A flowchart illustrating a method for detecting hydrogen leakage in an electric vehicle fuel cell according to the present invention is shown.

[0017] Figure 2 Schematic graphs showing the change of gas pressure over time in the cathode and anode of a fuel cell when performing the method according to the invention; and

[0018] Figure 3 A block diagram of a system for detecting hydrogen leakage in an electric vehicle fuel cell according to the present invention is shown. Detailed Implementation

[0019] Figure 1 A flowchart illustrating a method for detecting hydrogen leakage in an electric vehicle fuel cell according to the present invention is shown. (Refer to...) Figure 1 The method mainly includes the following steps:

[0020] S101: Detect the current SOC of the power battery pack of the electric vehicle and the current motion state of the electric vehicle to determine whether the fuel cell of the electric vehicle is currently shut down and estimate the duration of the fuel cell shut down in the current motion state of the electric vehicle, wherein the current motion state of the electric vehicle includes the current vehicle speed.

[0021] S201: If the estimated duration in step S101 reaches a predetermined duration threshold, hydrogen is introduced into the anode of the fuel cell to maintain the gas pressure in the anode at a constant value. At the same time, the gas pressure in the cathode of the fuel cell is detected and the rate of increase of the gas pressure in the cathode is calculated. If the rate of increase is greater than or equal to a predetermined rate of increase threshold, it is determined that there is an internal leakage of hydrogen from the anode to the cathode in the fuel cell.

[0022] The method may further include step S301: when the gas pressure in the cathode rises to the point that the gas pressure in the anode is the same as the gas pressure in the cathode, stop feeding hydrogen into the anode, detect the gas pressure in the anode and calculate the rate of decrease of the gas pressure in the anode, and if the rate of decrease is greater than or equal to a predetermined rate of decrease threshold, determine that there is an external leakage of hydrogen from the anode to the external environment in the fuel cell.

[0023] The method may further include step S401: when it is determined that there is an internal leak and / or an external leak in the fuel cell, a corresponding alarm signal is issued.

[0024] The method may further include step S501: after determining that there is an internal leak and / or an external leak in the fuel cell, opening the gas valves and discharge pipes at the anode and cathode to allow the gas in the anode and cathode to be discharged to the external environment.

[0025] Figure 2A schematic graph showing the change of gas pressure in the cathode and anode of a fuel cell over time when performing the method according to the invention is shown, wherein the horizontal axis T represents time, in units such as seconds, the vertical axis P represents gas pressure, in units such as bar, line L1 represents the change of gas pressure in the anode over time, and line L2 represents the change of gas pressure in the cathode over time. It should be noted that... Figure 2 Lines L1 and L2 schematically illustrate the changes in gas pressure over time within the anode and cathode of a fuel cell when both internal and external leaks are present. In the case of only one type of leak or no leak at all, lines L1 and L2 will have the same... Figure 2 The different trends shown below. This will be combined with... Figure 1 and Figure 2 The various steps of the method according to the present invention are described in detail.

[0026] First, the time point T1 corresponds to step S101, which can be summarized as the leak detection triggering stage, i.e., determining whether subsequent leak detection steps can be triggered.

[0027] As is known to those skilled in the art, the SOC (State of Charge) of the power battery pack of an electric vehicle indicates the remaining charge of the power battery pack. When the SOC of the power battery pack is high, the fuel cell of the electric vehicle can stop supplying power, that is, the electric vehicle can run without the fuel cell outputting electrical energy. However, when the SOC of the power battery pack drops to a certain level, a reaction needs to occur at the fuel cell stack to generate electrical energy in order to meet the power demand for the electric vehicle to continue running.

[0028] Since the method according to the present invention requires creating a specific environment in the fuel cell when determining whether an internal and / or external leak has occurred, namely, inputting and maintaining hydrogen at a specific pressure for a certain period of time, that is, it needs to be performed when the fuel cell stops supplying power for a certain period of time, it is necessary to first determine whether the current SOC of the power battery pack is high enough for the fuel cell to stop supplying power, and estimate the duration of the fuel cell stopping supplying power to determine whether the duration is sufficient to perform the subsequent leak detection steps.

[0029] Depending on the electric vehicle's overall energy management strategy, different electric vehicles may trigger the fuel cell to stop supplying power when the SOC of the battery pack reaches different values. That is, the fuel cell will stop supplying power as long as the SOC is greater than or equal to a certain value, such as when the SOC reaches 80% or 85%. Even when the fuel cell stops supplying power, the electric vehicle continues to drive and consumes the remaining charge of the battery pack at a certain power level. Similarly, depending on the different energy management strategies of the electric vehicle, different electric vehicles may trigger the fuel cell to restart supplying power when the SOC of the battery pack drops to different values, such as when the SOC drops to 40% or 45%. Given the electric vehicle's overall energy management strategy, if the current SOC of the battery pack is known and it is determined that the fuel cell has stopped supplying power at that SOC, the duration of the fuel cell's shutdown under the current motion state of the electric vehicle can be estimated based on the vehicle's current motion state, where the motion state mainly refers to vehicle speed. Specifically, given the current SOC of the power battery pack and the SOC value that triggers the fuel cell to restart power supply, it is possible to know the amount of electricity that the electric vehicle can continue to consume when the fuel cell stops supplying power. Furthermore, if the current speed of the electric vehicle is known, the current power of the electric vehicle can be calculated, thereby estimating the sustainable time period for the electric vehicle to continue driving at the current speed until the fuel cell is triggered to restart power supply.

[0030] The aforementioned motion state may also include the driving mode of the electric vehicle. Different driving modes may affect the duration of the fuel cell's power outage, thus affecting the determination of whether the subsequent leak detection step S101 should be triggered. For example, for considerations such as driving experience, when the electric vehicle is in certain driving modes, the subsequent leak detection step may not be triggered at all, even if the estimated duration of the fuel cell's power outage based on the current SOC of the power battery pack and the current speed of the electric vehicle is sufficient to execute the subsequent leak detection step. In this way, the determination of whether to trigger the subsequent leak detection step can be more flexible.

[0031] Figure 2 The time period between time point T1 and time point T2 corresponds to step S201, which can be summarized as the internal leak detection stage. In this stage, if it is determined that the estimated duration in step S101 has reached a predetermined duration threshold, hydrogen is introduced into the anode of the fuel cell to maintain the gas pressure within the anode at a constant value. Figure 2As shown, the gas pressure inside the anode will rapidly rise to a certain value and remain constant. For example, by introducing hydrogen into the anode, the gas pressure inside the anode can rise from 1 bar to 1.5 bar and remain at 1.5 bar until the internal leak detection phase ends. The predetermined duration threshold corresponds to... Figure 2 The interval between time point T1 and time point T4 in the data.

[0032] In the absence of internal leaks in a fuel cell, if hydrogen is continuously supplied to the anode at a constant pressure, the hydrogen will permeate through the proton exchange membrane into the cathode at a relatively low rate, resulting in a relatively low increase in gas pressure within the cathode. However, if an internal leak exists in the fuel cell, such as a significant hole in the proton exchange membrane, then with a continuous supply of hydrogen to the anode and a constant pressure, hydrogen will permeate through these holes into the cathode at a significantly higher rate, resulting in a significantly higher increase in gas pressure within the cathode.

[0033] Therefore, in step S201, while hydrogen is introduced into the anode of the fuel cell to maintain the gas pressure within the anode at a constant value, the gas pressure within the cathode of the fuel cell is detected, and the rate of increase of the gas pressure within the cathode is calculated. If this rate of increase is greater than or equal to a predetermined rate of increase threshold, it can be determined that the increase in gas pressure within the cathode is not due to normal hydrogen permeation through the proton exchange membrane, but rather due to a significant leak in the proton exchange membrane. This indicates an internal leak in the fuel cell from the anode to the cathode. Furthermore, the magnitude of the rate of increase of the gas pressure within the cathode indicates the degree of internal leakage. Generally, the greater the rate of increase of the gas pressure within the cathode, the higher the level of leakage in the proton exchange membrane, meaning a greater degree of internal leakage.

[0034] The aforementioned rise rate threshold can be adjustable rather than fixed, for example, it can be set according to actual needs, such as the sensitivity requirements for internal leak detection. Furthermore, the constant value maintained within the anode gas pressure also affects the rise rate threshold. Given the same level of leakage in the proton exchange membrane, the higher the constant value maintained within the anode gas pressure, the greater the gas pressure difference between the anode and cathode, and naturally, the faster the rate of hydrogen permeation or leakage from the anode to the cathode. Therefore, the rise rate threshold also needs to be set according to the magnitude of the constant value maintained within the anode gas pressure. For example, if the gas pressure within the anode is maintained at a constant value of 1.5 bar during the internal leak detection phase, the rise rate threshold can be set to 15 hPa / s. If the calculated rise rate of the gas pressure within the cathode is greater than or equal to this value, it can be determined that there is an internal leak in the fuel cell from the anode to the cathode.

[0035] like Figure 2 As shown, the internal leak detection phase begins at time point T1 and ends at time point T2. Time point T2 corresponds to the point when the gas pressure inside the anode and the gas pressure inside the cathode reach the same level. This means there is no longer a pressure difference between the anode and cathode, and hydrogen will no longer leak from the anode to the cathode due to the pressure difference. The time period from time point T2 to time point T3 corresponds to step S301, which can be summarized as the external leak detection phase. Starting at time point T2, the supply of hydrogen to the anode is stopped. If there is an external leak of hydrogen from the anode to the external environment, the gas pressure inside the anode will gradually decrease. Since the gas pressure inside the anode is the same as the gas pressure inside the cathode at time point T2, if the gas pressure inside the anode still decreases significantly after the supply of hydrogen is stopped, it indicates that there is a leak in the anode itself causing hydrogen to leak to the external environment.

[0036] Therefore, the external leak detection performed in step S301 may include: stopping the input of hydrogen to the anode when the gas pressure inside the anode and the gas pressure inside the cathode reach the same level; detecting the gas pressure inside the anode and calculating the rate of decrease of the gas pressure inside the anode; if the rate of decrease is greater than or equal to a predetermined rate of decrease threshold, then it is determined that there is an external leak of hydrogen from the anode to the external environment in the fuel cell. Similar to the rate of increase threshold, the aforementioned rate of decrease threshold is also adjustable, for example, depending on the magnitude of the constant value maintained by the gas pressure inside the anode during the internal leak detection phase. This is because, given the same level of leakage in the anode itself, the higher the constant value maintained by the gas pressure inside the anode during the internal leak detection phase, the greater the gas pressure difference between the anode and the outside, and naturally, the faster the rate at which hydrogen leaks from the anode to the outside.

[0037] from Figure 2 It can be seen that from time point T2 to time point T3, under the condition of external leakage, the gas pressure inside the anode gradually decreases, and the gas pressure inside the cathode also decreases accordingly. This is because the leakage of hydrogen from the anode to the outside causes a decrease in the gas pressure inside the anode, resulting in a pressure difference between the cathode and the anode. This pressure difference causes hydrogen to permeate from the cathode through the proton exchange membrane to the anode, causing a decrease in the gas pressure inside the cathode. In other words, under the condition of leakage from the anode to the outside, the permeation of hydrogen from the cathode through the proton exchange membrane to the anode under the influence of the pressure difference will compensate for the decrease in the gas pressure inside the anode. Therefore, the setting of the aforementioned rate of decrease threshold also needs to consider the compensation for the decrease in gas pressure inside the anode caused by hydrogen permeating from the cathode through the proton exchange membrane to the anode.

[0038] from Figure 2It can also be seen that from time point T2 to time point T3, under the condition of external leakage, the rate of decrease in gas pressure inside the anode is generally greater than the rate of decrease in gas pressure inside the cathode. This corresponds to the situation where there is an external leakage at the anode but no or only a small leakage from the cathode to the external environment. In this case, the rate at which hydrogen leaks into the external environment through the anode is greater than the rate at which hydrogen permeates from the cathode through the proton exchange membrane to the anode. However, despite Figure 2 (Not shown) There is also a possibility that a leak occurs at the cathode, causing hydrogen to leak from the cathode into the external environment. In this case, the trends of lines L1 and L2 between time point T2 and time point T3 may be different. Figure 2 The difference shown is that the rate of decrease in gas pressure inside the cathode is greater than... Figure 2 The rate of decrease is faster, possibly even faster than the rate of decrease in gas pressure within the anode.

[0039] In general, during the external leak detection phase, assuming the gas pressure inside the anode is maintained at a constant value during the internal leak detection phase, the greater the rate of decrease in the gas pressure inside the anode, the higher the degree of external leak.

[0040] It should be noted that during the internal leak detection phase, the rate of increase of gas pressure within more than one cathode can be calculated. An internal leak is determined to exist when the calculated rate of increase is greater than or equal to a predetermined threshold, or when the average of the calculated rates of increase is greater than or equal to a predetermined threshold. Similarly, during the external leak detection phase, the rate of decrease of gas pressure within more than one anode can be calculated. An external leak is determined to exist when the calculated rate of decrease is greater than or equal to a predetermined threshold, or when the average of the calculated rates of decrease is greater than or equal to a predetermined threshold. This method improves the accuracy of identifying both internal and external leaks.

[0041] like Figure 1As shown, the method according to the present invention may include step S401: when it is determined that there is an internal leak and / or an external leak in the fuel cell, a corresponding alarm signal is issued. The alarm signal may only indicate the existence of an internal leak and / or an external leak, or it may indicate the degree of the internal leak and / or external leak. The method for assessing the degree of the internal leak and / or external leak has been explained above and will not be repeated here. The driver and / or maintenance personnel can receive the alarm signal in the cockpit or remotely, so as to be promptly informed that an internal leak and / or external leak has occurred in the fuel cell, and thus take appropriate countermeasures when necessary. Especially for external leaks, if the degree of hydrogen leakage into the external environment is high, there is a risk of fire or even explosion. Therefore, when the driver and / or maintenance personnel receive an alarm signal indicating an external leak, they can inspect and replace the fuel cell after stopping the vehicle. When necessary, for example, if the alarm signal indicates a high degree of external leak, the electric vehicle can even be directly triggered to stop driving immediately, so that the driver and / or maintenance personnel can inspect and replace the fuel cell as soon as possible.

[0042] As previously stated, the method according to the present invention requires the gas pressure in the anode and the gas pressure in the cathode to reach the same time point T2 before the external leak detection phase can begin. The interval between time points T1 and T2 varies depending on the degree of internal leakage, i.e., the level of leakage in the proton exchange membrane. On the other hand, during the external leak detection phase, the rate of decrease in gas pressure in the anode varies depending on the level of leakage in the anode itself. In the case of no leakage or only a very small leakage in the anode, the gas pressure in both the anode and cathode will remain at a high pressure level for a long period of time. Therefore, the duration of each of the internal and external leak detection phases may be uncertain, leading to uncertainty in the predetermined duration threshold set during the leak detection triggering phase. Furthermore, if there is no external leakage, the high gas pressure in the anode and cathode may adversely affect the normal operation of the fuel cell after the method of the present invention is terminated. To overcome this problem, it is preferable to pre-set predetermined time periods for the internal and external leak detection phases, and terminate the corresponding internal and external leak detection phases once the predetermined time periods are reached.

[0043] Specifically, a first predetermined time period, such as 2 minutes or 3 minutes, can be set for the internal leak detection phase. Starting from time point T1, if the gas pressure in the anode and the gas pressure in the cathode reach the same level within the first predetermined time period (corresponding to time point T2), the supply of hydrogen to the anode is immediately stopped, and the external leak detection phase begins. However, if the gas pressure in the anode and the gas pressure in the cathode do not reach the same level after the first predetermined time period, the internal leak detection phase is immediately stopped, and the external leak detection is not performed at this time. This is because there is still a pressure difference between the gas pressure in the anode and the gas pressure in the cathode. If the supply of hydrogen to the anode is stopped, it is impossible to determine whether the subsequent drop in gas pressure in the anode is due to an external leak or due to the pressure difference causing hydrogen to permeate from the anode through the proton exchange membrane to the cathode.

[0044] If the gas pressure in the anode and the gas pressure in the cathode do not reach the same level after the first predetermined time period, it may be due to a leak in the cathode itself. In this case, although hydrogen gas in the anode permeates through the proton exchange membrane or leaks into the cathode through the leak in the proton exchange membrane, hydrogen gas will also leak into the external environment from the leak in the cathode itself, making it impossible for the gas pressure in the anode and the cathode to reach the same level, that is, the conditions for performing external leak detection cannot be met. On the other hand, a malfunction in the sensor or other components that sense the gas pressure in the anode and / or cathode may also cause the gas pressure in the anode and the cathode to not reach the same level after the first predetermined time period. During the operation of the electric vehicle, the method according to the present invention can be executed multiple times. If the gas pressure in the anode and the gas pressure in the cathode do not reach the same level after the first predetermined time period multiple times (e.g., two, three times, etc.), an alarm signal can be generated. This alarm signal can indicate that there may be a leak in the cathode itself or that the sensor or other components that sense the gas pressure in the anode and / or cathode are malfunctioning. After receiving the alarm signal, the driver and / or maintenance personnel can perform targeted inspections.

[0045] On the other hand, a second predetermined time period, such as 30 seconds, can be set for the external leakage detection stage. After the second predetermined time period has elapsed from the time point T2 when hydrogen is stopped being introduced into the anode, the external leakage detection stage ends immediately, that is, the gas valves and discharge pipes at the anode and cathode are opened immediately, so that the gas in the anode and cathode is discharged into the external environment.

[0046] like Figure 2As shown, at time point T3, the external leak detection phase ends, but the gas pressure in the anode and cathode is still higher than the initial gas pressure levels in the anode and cathode before time point T1. Since the fuel cell may need to continue operating after the method of the present invention ends, excessively high gas pressure in the anode and cathode will adversely affect the normal operation of the fuel cell after the method of the present invention ends. Therefore, the time period between time point T3 and time point T4 corresponds to step S501, which can be summarized as the hydrogen release phase. Step S501 can be implemented by opening the gas valves and discharge pipes at the anode and cathode, so that the gas in the anode and cathode is rapidly discharged to the external environment.

[0047] It should be noted that Figure 2 The hydrogen release phase is shown to occur after both the internal and external leak detection phases have been completed. However, as mentioned earlier, in some cases, if the gas pressure in the cathode has not risen to the same level as the gas pressure in the cathode within a first predetermined time period after the hydrogen is introduced into the anode of the fuel cell, the subsequent external leak detection phase is not performed. In this case, the hydrogen release phase is performed directly after the first predetermined time period, i.e., at time point T2. That is, the hydrogen release phase must be performed regardless of whether the external leak detection phase has been performed. Whether the hydrogen release phase is performed after determining the existence of an internal or external leak depends on whether the gas pressure in the anode and the gas pressure in the cathode have reached the same level at time point T2.

[0048] By setting a first predetermined time period for the internal leak detection phase and a second predetermined time period for the external leak detection phase, the uncertainty in the duration of each phase is eliminated. This allows the time required to execute the method to be clearly determined before it begins, enabling accurate judgment on whether subsequent leak detection steps should be triggered. Furthermore, the second predetermined time period eliminates the adverse effects of high gas pressures within the anode and cathode in the absence of external leaks on the normal operation of the fuel cell after the method of this invention is completed.

[0049] Because the gas valves and exhaust pipes at both the anode and cathode are opened during the hydrogen release phase, the hydrogen gas inside the anode and cathode can be rapidly released to the outside. Therefore, the duration of the release phase can be set to be short, such as a few seconds. Figure 2 It can be seen that the gas in the anode and then the cathode may have been completely released before the end of the release phase (i.e. before time point T4), meaning that the gas pressure in both the anode and the cathode has roughly reached atmospheric pressure.

[0050] The present invention also proposes a system for detecting hydrogen leakage in the fuel cells of electric vehicles. Figure 3 A block diagram of the system 10 according to the present invention is shown. From Figure 3 It can be seen that system 10 includes:

[0051] The controller 100 is configured to detect the current state of charge (SOC) of the power battery pack 110 of the electric vehicle and the current state of motion of the electric vehicle to determine whether the fuel cell 120 of the electric vehicle is currently shut down and to estimate the duration of the shutdown of the fuel cell 120 in the current state of motion of the electric vehicle, wherein the current state of motion of the electric vehicle includes the current vehicle speed.

[0052] Hydrogen injection valve 200 is configured to supply hydrogen to the anode 121 of fuel cell 120 to maintain the gas pressure in the anode 121 at a constant value when the duration estimated by controller 100 reaches a predetermined duration threshold.

[0053] An anode gas pressure sensor 300 is configured to sense the gas pressure within the anode 121, and a cathode gas pressure sensor 400 is configured to sense the gas pressure within the cathode 122 of the fuel cell.

[0054] The controller 100 is further configured to calculate the rate of increase of the gas pressure in the cathode 122 while maintaining the gas pressure in the anode 121 at a constant value. If the rate of increase is greater than or equal to a predetermined rate of increase threshold, it is determined that there is an internal leakage of hydrogen from the anode 121 to the cathode 122 in the fuel cell 120.

[0055] When the gas pressure in the cathode 122 rises to the point that the gas pressure in the anode 121 is the same as the gas pressure in the cathode 122, the hydrogen injection valve 200 is further configured to stop supplying hydrogen to the anode 121, and the controller 100 is further configured to calculate the rate of decrease of the gas pressure in the anode 121 based on the gas pressure in the anode 121 sensed by the anode gas pressure sensor 300, and if the rate of decrease is greater than or equal to a predetermined rate of decrease threshold, it is determined that there is an external leakage of hydrogen from the anode 121 to the external environment in the fuel cell.

[0056] Figure 3 The system 10 is also shown to include an alarm module 500 configured to communicate with the controller 100 and to issue a corresponding alarm signal when the controller 100 determines that an internal leak and / or an external leak has occurred.

[0057] Figure 3The system 10 is also shown to include a hydrogen release module 600, which is configured to communicate with the controller 100 and includes gas valves and discharge pipes for anode and cathode to perform the aforementioned hydrogen release phase process.

[0058] In summary, the method and system for detecting hydrogen leakage in the fuel cell of an electric vehicle, as described in this invention, can detect both internal and external hydrogen leakage in the fuel cell without affecting the normal operation of the electric vehicle. Furthermore, the hardware involved in the detection is all existing hardware of the fuel cell of the electric vehicle (such as anode gas pressure sensor, cathode pressure sensor, and hydrogen injection valve), achieving highly efficient and reliable leakage detection without increasing hardware and space costs.

[0059] In general, the system 10 according to the present invention can perform the aforementioned steps of the method according to the present invention, and the implementation of each step will not be described in detail here.

[0060] The present invention also proposes a computer program product comprising computer instructions that, when executed by a processor, implement the method according to the present invention.

[0061] The present invention also proposes a machine-readable storage medium, which may be the aforementioned memory, storing computer instructions that, when executed by a processor, implement the method according to the present invention.

[0062] The foregoing description, with reference to the accompanying drawings, details feasible but non-limiting embodiments of the method and system for detecting hydrogen leakage in an electric vehicle fuel cell according to the present invention. Modifications and additions to the technology and structure, as well as recombinations of features in the various embodiments, should be considered within the scope of the invention by those skilled in the art, without departing from the scope and spirit of the invention as set forth in the following claims. Therefore, such modifications and additions conceivable under the teachings of this invention should be considered part of the invention. The scope of the invention is defined by the following appended claims and includes equivalent technologies known at the filing date of this invention and equivalent technologies not yet foreseen.

Claims

1. A method for detecting hydrogen leakage in the fuel cell of an electric vehicle, including: The system detects the current state of charge (SOC) of the electric vehicle's battery pack and the current motion state of the electric vehicle to determine whether the fuel cell of the electric vehicle is currently not supplying power and to estimate the duration of the fuel cell's power outage under the current motion state of the electric vehicle, wherein the current motion state of the electric vehicle includes the current vehicle speed; and If the estimated duration reaches a predetermined duration threshold, hydrogen is introduced into the anode of the fuel cell to maintain the gas pressure in the anode at a constant value. At the same time, the gas pressure in the cathode of the fuel cell is detected and the rate of increase of the gas pressure in the cathode is calculated. If the rate of increase is greater than or equal to a predetermined rate of increase threshold, it is determined that there is an internal leakage of hydrogen from the anode to the cathode in the fuel cell.

2. The method according to claim 1, further comprising: When the gas pressure in the cathode rises to the point that the gas pressure in the anode becomes the same as the gas pressure in the cathode, the input of hydrogen to the anode is stopped. The gas pressure in the anode is detected and the rate of decrease of the gas pressure in the anode is calculated. If the rate of decrease is greater than or equal to a predetermined rate of decrease threshold, it is determined that there is an external leakage of hydrogen from the anode to the external environment in the fuel cell.

3. The method according to claim 2, further comprising: When it is determined that the fuel cell has internal leakage and / or external leakage, a corresponding alarm signal is issued.

4. The method of claim 2, further comprising: After determining that the fuel cell has internal and / or external leaks, the gas valves and exhaust pipes at the anode and cathode are opened to allow the gas in the anode and cathode to be discharged into the external environment.

5. The method according to any one of claims 1 to 4, further comprising: An external leak of hydrogen from the anode to the external environment is determined only when the gas pressure in the cathode rises to the same level as the gas pressure in the anode within a first predetermined time period after the hydrogen is introduced into the anode of the fuel cell.

6. The method according to any one of claims 1 to 4, further comprising: If the gas pressure in the cathode does not rise to the same level as the gas pressure in the cathode within a first predetermined time period after the hydrogen is introduced into the anode of the fuel cell, the gas valves and discharge pipes at the anode and cathode are opened to allow the gas in the anode and cathode to be discharged into the external environment.

7. The method of claim 2, further comprising: After a second predetermined time period elapses from the point when hydrogen is stopped being supplied to the anode, the gas valves and discharge pipes at the anode and cathode are opened, allowing the gas inside the anode and cathode to be discharged into the external environment.

8. A system (10) for detecting hydrogen leakage in the fuel cell of an electric vehicle, comprising: A controller (100) is configured to detect the current state of charge (SOC) of the power battery pack (110) of the electric vehicle and the current state of motion of the electric vehicle to determine whether the fuel cell (120) of the electric vehicle is currently shut down and to estimate the duration of the shutdown of the fuel cell (120) in the current state of motion of the electric vehicle, wherein the current state of motion of the electric vehicle includes the current vehicle speed. A hydrogen injection valve (200) is configured to supply hydrogen to the anode (121) of the fuel cell (120) to maintain the gas pressure in the anode (121) at a constant value when the duration estimated by the controller (100) reaches a predetermined duration threshold. An anode gas pressure sensor (300) configured to sense the gas pressure within the anode (121) and a cathode gas pressure sensor (400) configured to sense the gas pressure within the cathode (122) of the fuel cell. The controller (100) is further configured to calculate the rate of increase of the gas pressure in the cathode (122) while maintaining the gas pressure in the anode (121) at the constant value. If the rate of increase is greater than or equal to a predetermined rate of increase threshold, it is determined that there is an internal leakage of hydrogen from the anode (121) to the cathode (122) in the fuel cell (120).

9. The system (10) according to claim 8, wherein When the gas pressure in the cathode (122) rises to the point that the gas pressure in the anode (121) is the same as the gas pressure in the cathode (122), the hydrogen injection valve (200) is further configured to stop supplying hydrogen to the anode (121), and the controller (100) is further configured to calculate the rate of decrease of the gas pressure in the anode (121) based on the gas pressure in the anode (121) sensed by the anode gas pressure sensor (300), and if the rate of decrease is greater than or equal to a predetermined rate of decrease threshold, it is determined that there is an external leakage of hydrogen from the anode (121) to the external environment in the fuel cell.

10. A computer program product comprising computer instructions that, when executed by a processor, implement the method according to any one of claims 1 to 7.

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