Fuel cell leakage detection method and device

Abstract

The invention relates to the technical field of fuel cell detection, in particular to a fuel cell leakage detection method and device. The device obtains actual operation parameters of a fuel cell and stores set threshold values of the parameters, and the actual operation parameters comprise hydrogen path inlet and outlet pressure drop, air path inlet and outlet pressure drop, inlet and outlet temperature of the fuel cell, a fuel cell impedance value, a coolant pump rotating speed, a water pump outlet pressure change value and a voltage change rate of the fuel cell in a preset time period. Wherein the fuel cell impedance value comprises a high-frequency impedance value and a low-frequency impedance value; and according to the actual operation parameters and threshold values corresponding to the parameters, whether leakage occurs between the gas path and the cooling liquid path or not is determined.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cell detection, and in particular to a fuel cell leakage detection method and device. Background Art

[0002] A fuel cell is a device that converts chemical energy into electrical energy by reacting hydrogen and air. It consists of three circuits: a hydrogen circuit, an air circuit, and a coolant circuit. The hydrogen circuit and the air circuit provide the gas required for the reaction, and the coolant circuit provides the coolant required for the reaction to dissipate heat.

[0003] If there is leakage between the hydrogen path, air path and coolant path, on the one hand, the coolant will enter the hydrogen path or air path and cover the membrane electrode reaction active sites, reducing performance and affecting the service life of the fuel cell; on the other hand, the gas in the hydrogen path and air path entering the coolant path will cause uneven temperature distribution of the stack, forming local hot spots, affecting the service life of the fuel cell, and in severe cases, it can cause fuel cell ablation, affecting the safety of the fuel cell system. Therefore, it is very important to effectively monitor the leakage of the gas path and coolant path during the operation of the fuel cell system.

[0004] In the prior art, only the leakage from the coolant to the gas circuit or the leakage from the hydrogen circuit to the coolant circuit is monitored, and the two-way leakage monitoring of the coolant circuit and the gas circuit cannot be realized. If the mutual leakage between the gas circuit and the coolant circuit cannot be discovered in time during the operation of the fuel cell, the efficiency and life of the battery will be affected, and in serious cases, safety problems will be caused. Therefore, a detection method and device are needed to realize real-time monitoring and detection of whether the gas circuit and the coolant circuit leak each other during the operation of the fuel cell. Summary of the invention

[0005] The problem to be solved by the present invention is to provide a detection method and a device to detect whether there is mutual leakage between the gas circuit and the cooling liquid circuit.

[0006] In view of the deficiencies of the prior art, the technical solution adopted by the present invention to solve the technical problems is: a fuel cell leakage detection method, which obtains the actual operating parameters of the fuel cell and sets thresholds corresponding to each parameter, the actual operating parameters include the inlet and outlet pressure drop of the hydrogen path, the inlet and outlet pressure drop of the air path, the inlet and outlet temperature of the fuel cell, the fuel cell impedance value, the coolant pump speed, the water pump outlet pressure change value and the voltage change rate of the fuel cell within a predetermined time period, wherein the fuel cell impedance value includes a high-frequency impedance value and a low-frequency impedance value; the thresholds corresponding to the actual operating parameters include the inlet and outlet pressure drop threshold of the hydrogen path, the inlet and outlet pressure drop threshold of the air path, the inlet and outlet temperature threshold of the coolant path, the fuel cell impedance threshold, the coolant pump speed threshold, the coolant pump outlet pressure change threshold and the voltage change rate threshold, and the fuel cell impedance threshold includes a high-frequency impedance threshold and a low-frequency impedance threshold; whether a leakage occurs between the gas path and the coolant path is determined according to the actual operating parameters and the thresholds corresponding to the parameters.

[0007] Preferably, whether gas leaks into the coolant circuit is determined based on the coolant pump speed of the fuel cell, the coolant pump outlet pressure change value, the coolant circuit inlet and outlet temperature and temperature difference within a predetermined time period. The thresholds involved in the judgment process include: coolant pump speed threshold, coolant pump outlet pressure change threshold, and coolant circuit inlet and outlet temperature threshold.

[0008] Preferably, the specific process of determining whether the gas leaks into the cooling liquid path is as follows:

[0009] S1: Acquire actual operating parameters and thresholds corresponding to the parameters during operation, the actual operating parameters include the speed of the coolant pump of the fuel cell, the change value of the coolant pump outlet pressure, the inlet and outlet temperatures and temperature difference of the coolant path; the acquired thresholds include the coolant pump speed threshold, the coolant pump outlet pressure change threshold, and the inlet and outlet temperature threshold of the coolant path;

[0010] S2: When it is determined that the change value of the coolant pump outlet pressure within the predetermined time period is greater than the coolant pump outlet pressure change threshold, enter S3;

[0011] S3: Determine whether the outlet temperature of the fuel cell increases to the outlet temperature threshold; if not, proceed to S7; if yes, proceed to S4;

[0012] S4: Determine whether the coolant pump speed is reduced to the coolant pump speed threshold; if not, proceed to S7; if yes, proceed to S5;

[0013] S5: Adjust the speed of the coolant pump to adjust the inlet and outlet temperatures to a normal range within the set temperature difference;

[0014] S6: Determine whether the coolant pump speed is higher than the coolant pump speed threshold; if not, proceed to S7; if yes, proceed to S8;

[0015] S7: Check the cause of the abnormality; end the operation;

[0016] S8: It is determined that the gas has leaked into the coolant line, and the operation is terminated.

[0017] Preferably, whether the coolant has leaked into the gas circuit is judged based on the voltage change rate, the hydrogen circuit inlet and outlet pressure drop, the air circuit inlet and outlet pressure drop, the fuel cell impedance value and the corresponding thresholds within a predetermined time period; the thresholds involved in whether the coolant has leaked into the gas circuit include the voltage change rate threshold, the hydrogen circuit inlet and outlet pressure drop threshold, the air circuit inlet and outlet pressure drop threshold, and the fuel cell impedance threshold.

[0018] Preferably, the specific process of whether the coolant leaks to the gas path is as follows:

[0019] S1: Acquire actual operating parameters and thresholds during operation: voltage change rate, hydrogen path inlet and outlet pressure drop, air path inlet and outlet pressure drop, and fuel cell impedance value within a predetermined time period; the thresholds involved include voltage change rate threshold, hydrogen path inlet and outlet pressure drop threshold, air path inlet and outlet pressure drop threshold, and fuel cell impedance threshold (including high-frequency impedance threshold and low-frequency impedance threshold);

[0020] S2: When it is determined that the voltage change rate within the predetermined time period is greater than the voltage change rate threshold, enter S3;

[0021] S3: Determine whether the operating condition deviates from the set value: if the operating condition deviates from the set value, the operating condition is corrected. After the operating condition is corrected, if the voltage change rate changes within the threshold, the operation continues; if the operating condition does not deviate from the set value, enter S4;

[0022] S4: Determine whether the pressure drop of the gas path inlet and outlet is greater than the corresponding threshold, and whether the high-frequency and low-frequency impedances are greater than the fuel cell impedance threshold;

[0023] S5: Determine whether the increase in the hydrogen path inlet and outlet pressure drop exceeds the hydrogen path inlet and outlet pressure drop threshold, whether the high-frequency and low-frequency impedances increase, and whether the increase in the high-frequency impedance exceeds the fuel cell impedance threshold; if the hydrogen path inlet and outlet pressure drop increases and exceeds the hydrogen path inlet and outlet pressure drop threshold, whether the high-frequency and low-frequency impedances increase, and whether the high-frequency impedance increases and exceeds the fuel cell impedance threshold, then it is determined that the coolant path leaks to the hydrogen path; if not, enter S5;

[0024] S6: If the air path inlet and outlet pressure drop increases and exceeds the air path inlet and outlet pressure drop threshold, the high-frequency and low-frequency impedances both increase, and the low-frequency impedance increases and exceeds the threshold, it is determined that the coolant path leaks to the hydrogen path;

[0025] S7: End the operation after checking the abnormal cause, the coolant line leaks into the hydrogen line, or the coolant line leaks into the air line.

[0026] A fuel cell leakage detection device comprises a control module, the control module is connected to a storage module, a transmission module, an input module, an output module and a controlled system, and the device obtains actual operating parameters and stores setting thresholds of various parameters.

[0027] The beneficial effects of the present invention are as follows: The method of the present invention determines whether a leakage occurs between the gas circuit and the coolant circuit according to the threshold values ​​set for each parameter corresponding to the actual operating parameters of the fuel cell obtained by the detection device, thereby solving the problem of how to effectively monitor whether the gas circuit and the coolant circuit are leaking during the operation of the fuel cell system. It not only monitors the problem of leakage from the coolant circuit to the gas circuit, but also monitors whether the gas is leaking to the coolant circuit, thereby ensuring the operating safety and efficiency of the fuel cell.

[0028] 1. Bidirectional leak detection: Through a step-by-step logic judgment mechanism, it can identify gas leaks into the coolant line (such as hydrogen or air leaks into the coolant system), and can also detect coolant leaks into the gas line (such as coolant leaks into the hydrogen line or air line), thus achieving simultaneous monitoring and detection of bidirectional leaks.

[0029] 2. Multi-parameter collaborative analysis: Combining the threshold judgment of multiple parameters such as pressure drop, impedance, temperature, and rotation speed significantly improves the accuracy and reliability of leak detection. For example, the difference between high-frequency impedance and low-frequency impedance can accurately distinguish the type and path of leaks.

[0030] 3. Adaptive adjustment function: When a parameter abnormality is detected, the system can automatically adjust the operating conditions (such as the coolant pump speed) to try to correct the operating status, further eliminate the possibility of misjudgment, and ensure the accuracy of the diagnosis results. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a hardware structure block diagram of the detection device of the present invention;

[0032] Figure 2 is a control diagram of a method for detecting leakage of a gas path to a cooling liquid path according to the present invention;

[0033] Figure 3 is a control diagram of a method for detecting coolant leakage into a gas path according to the present invention;

[0034] Explanation of the accompanying drawings: 1. control module; 2. storage module; 3. transmission module; 4. input module; 5. output module; 6. controlled system. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present invention are provided for the purpose of illustration and description, and are not intended to be exhaustive or to limit the present invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention, and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

[0036] The main purpose of the present invention is to provide a fuel cell leakage diagnosis method and device to solve the problem that the prior art cannot monitor whether there is a two-way leakage between the gas path and the coolant path of the fuel cell during operation, thereby ensuring safe operation.

[0037] A fuel cell leakage detection method includes a fuel cell, and actual operating parameters during system operation, the actual operating parameters include hydrogen path inlet and outlet pressure drop, air path inlet and outlet pressure drop, fuel cell inlet and outlet temperature, fuel cell impedance value (high frequency impedance value and low frequency impedance value), coolant pump speed, water pump outlet pressure change value, and fuel cell voltage change rate within a predetermined period; according to the actual operating parameters and the corresponding parameter thresholds, the thresholds corresponding to the actual operating parameters include hydrogen path inlet and outlet pressure drop threshold, air path inlet and outlet pressure drop threshold, coolant path inlet and outlet temperature threshold, fuel cell impedance threshold (including high frequency impedance threshold and low frequency impedance threshold), coolant pump speed threshold, coolant pump outlet pressure change threshold, and voltage change rate threshold, and according to the actual operating parameters and the thresholds corresponding to the parameters, determine whether there is a leak between the gas path and the coolant path. The operating condition parameters of the system correspond to the current value, and the operating condition parameters corresponding to different currents are pre-stored in the control module 1 of the system at the beginning.

[0038] Whether the gas leaks into the coolant line is determined based on the coolant pump speed, coolant pump outlet pressure change value, coolant line inlet and outlet temperature and temperature difference of the fuel cell in a predetermined time period. The thresholds used to determine whether the gas leaks into the coolant line include: coolant pump speed threshold, coolant pump outlet pressure change threshold, and coolant line inlet and outlet temperature threshold. The specific judgment process is as follows:

[0039] S1: Acquire actual operating parameters and thresholds corresponding to the parameters during operation, the actual operating parameters include the speed of the coolant pump of the fuel cell, the change value of the coolant pump outlet pressure, the inlet and outlet temperatures and temperature difference of the coolant path; the acquired thresholds include the coolant pump speed threshold, the coolant pump outlet pressure change threshold, and the inlet and outlet temperature threshold of the coolant path;

[0040] For example: the preset time period is 10 minutes, the fuel cell outlet temperature threshold is set to be greater than the set value of 3. C, the inlet and outlet temperature difference is set to be 10. C, the coolant pump speed threshold is set to be greater than the set value of 5%, and the coolant pump outlet pressure change threshold and voltage change rate threshold are set according to actual conditions. (The thresholds are only reference values, and users can modify them according to the actual conditions of the fuel cell system, but the detection method is the same)

[0041] S2: When it is determined that the change value of the coolant pump outlet pressure within the predetermined time period is greater than the coolant pump outlet pressure change threshold, enter S3;

[0042] S3: Determine whether the outlet temperature of the fuel cell increases to the outlet temperature threshold; if not, proceed to S7; if yes, proceed to S4;

[0043] S4: Determine whether the coolant pump speed is reduced to the coolant pump speed threshold; if not, proceed to S7; if yes, proceed to S5;

[0044] S5: Adjust the speed of the coolant pump to adjust the inlet and outlet temperatures to a normal range within the set temperature difference;

[0045] S6: Determine whether the coolant pump speed is higher than the coolant pump speed threshold; if not, proceed to S7; if yes, proceed to S8;

[0046] S7: Check the cause of the abnormality and end the operation;

[0047] S8: It is determined that the gas has leaked into the coolant line, and the operation is terminated.

[0048] First, determine whether the change value of the water pump outlet pressure of the fuel cell exceeds the set value within a predetermined time period under the same current, and then determine whether the outlet temperature of the fuel cell increases to a threshold value and whether the coolant pump speed decreases to a threshold value. Then adjust the coolant pump speed and adjust the inlet and outlet temperatures to a normal range. At this time, if the coolant pump speed is higher than the threshold value, it can be determined that gas has leaked into the coolant circuit.

[0049] Figure 1 : is a hardware structure block diagram of a computing device. The method can be executed in a mobile terminal, a computer terminal or a similar computing device. The computing device may include a control module 1, a storage module 2 for storing data, a transmission module 3, an input module 4, and an output module 5. The control module 1 is connected to the storage module 2, the transmission module 3, the input module 4, the output module 5 and the controlled system 6.

[0050] The control module 1 executes various functional applications and data processing (system instructions, system operating condition setting instructions, judgment of whether a condition exceeds a threshold, etc.). The storage module 2 can be used to store computer programs and data. The transmission module 3 converts specific numerical values ​​into analog quantities required by the output module via a network: all data required by the input module 4 and the output module 5. The input module 4 is responsible for the input of data, and the output module 5 is responsible for the output of data. The input data is the data collected by the sensor, and the output data is the specific instructions output to the actuator. The controlled system 6 is the actuator that implements the specific instructions.

[0051] Whether the coolant has leaked into the gas path is determined based on the voltage change rate, the hydrogen path inlet and outlet pressure drop, the air path inlet and outlet pressure drop, and the fuel cell impedance value within a predetermined time period.

[0052] First, determine whether the voltage change rate reaches the threshold value within a predetermined time period under the same current. On this basis, determine whether the operating parameters are given according to the preset values ​​(the operating condition parameters correspond to the current values). If the conditions deviate, correct the operating condition parameters first. After the correction is completed, if the voltage change rate is not significantly improved, proceed to the next step of judgment.

[0053] S1: Acquire actual operating parameters and thresholds during operation: voltage change rate, hydrogen path inlet and outlet pressure drop, air path inlet and outlet pressure drop, and fuel cell impedance value within a predetermined time period; the thresholds involved include voltage change rate threshold, hydrogen path inlet and outlet pressure drop threshold, air path inlet and outlet pressure drop threshold, and fuel cell impedance threshold (including high-frequency impedance threshold and low-frequency impedance threshold);

[0054] For example: the preset time period is 10 minutes, the voltage change rate threshold is set to be greater than the set value by 10%, the hydrogen inlet and outlet pressure drop threshold is set to be greater than the set value by 15%, the air inlet and outlet pressure drop threshold is set to be greater than the set value by 15%, the fuel cell impedance threshold (including high-frequency impedance threshold and low-frequency impedance threshold), the high-frequency impedance threshold is set to be greater than the set value by 5%, and the low-frequency impedance threshold is set to be greater than the set value by 5%. (The threshold is only a reference value, and the user can modify it according to the actual situation of the fuel cell system, but the detection method is the same)

[0055] S2: When it is determined that the voltage change rate within the predetermined time period is greater than the voltage change rate threshold, enter S3;

[0056] S3: Determine whether the operating condition deviates from the set value: if the operating condition deviates from the set value, the operating condition is corrected. After the operating condition is corrected, if the voltage change rate changes within the threshold, the operation continues; if the operating condition does not deviate from the set value, enter S4;

[0057] S4: Determine whether the pressure drop of the gas path inlet and outlet is greater than the corresponding threshold, and whether the high-frequency and low-frequency impedances are greater than the fuel cell impedance threshold;

[0058] S5: Determine whether the increase in the hydrogen path inlet and outlet pressure drop exceeds the hydrogen path inlet and outlet pressure drop threshold, whether the high-frequency and low-frequency impedances increase, and whether the increase in the high-frequency impedance exceeds the fuel cell impedance threshold; if the hydrogen path inlet and outlet pressure drop increases and exceeds the hydrogen path inlet and outlet pressure drop threshold, whether the high-frequency and low-frequency impedances increase, and whether the high-frequency impedance increases and exceeds the fuel cell impedance threshold, then it is determined that the coolant path leaks to the hydrogen path; if not, enter S5;

[0059] S6: If the air path inlet and outlet pressure drop increases and exceeds the air path inlet and outlet pressure drop threshold, the high-frequency and low-frequency impedances both increase, and the low-frequency impedance increases and exceeds the threshold, it is determined that the coolant path leaks to the hydrogen path;

[0060] S7: End the operation after checking the abnormal cause, the coolant line leaks into the hydrogen line, or the coolant line leaks into the air line.

[0061] If the inlet and outlet pressure drops of the hydrogen path and the air path exceed the threshold, and the increase of the high-frequency impedance and the low-frequency impedance exceeds the threshold, the coolant leaks into the hydrogen path and the air path.

[0062] The present invention provides a fuel cell leakage detection method and device, which aims to solve the problem that the prior art cannot monitor the bidirectional leakage between the gas circuit and the coolant circuit of the fuel cell in real time and comprehensively, thereby improving the operating safety and efficiency of the fuel cell system. The method obtains multi-dimensional operating data such as the inlet and outlet pressure drop of the hydrogen circuit, the inlet and outlet pressure drop of the air circuit, the impedance value of the fuel cell (including high-frequency and low-frequency impedance), the speed of the coolant pump, the change value of the water pump outlet pressure, the voltage change rate and the temperature parameter in real time, and dynamically compares it with the preset threshold value to comprehensively judge whether there is a leakage between the gas circuit and the coolant circuit. The device of the present invention can collect data in real time, perform threshold comparison and output control instructions to achieve fully automated detection. Compared with the prior art, it covers the bidirectional leakage scenarios of the gas circuit and the coolant circuit, filling the functional gap of the existing detection system. Through dynamic parameter correction and adaptive adjustment, the fault response time is shortened to avoid the safety risks caused by the degradation of the performance of the stack or local overheating due to leakage. The threshold parameters can be flexibly adjusted according to the fuel cell model and the operating environment, with strong adaptability and easy promotion and application. The present invention provides a reliable guarantee for the safe operation of the fuel cell system, can be widely used in the fields of new energy vehicles, fixed power stations, etc., and has significant economic benefits and social value.

Claims

1. A fuel cell leakage detection method, characterized in that: The actual operating parameters of the fuel cell are obtained and thresholds are set corresponding to each parameter, wherein the actual operating parameters include the hydrogen inlet and outlet pressure drop, the air inlet and outlet pressure drop, the fuel cell inlet and outlet temperature, the fuel cell impedance value, the coolant pump speed, the water pump outlet pressure change value, and the fuel cell voltage change rate within a predetermined time period, wherein the fuel cell impedance value includes a high-frequency impedance value and a low-frequency impedance value; the thresholds corresponding to the actual operating parameters include the hydrogen inlet and outlet pressure drop threshold, the air inlet and outlet pressure drop threshold, the coolant inlet and outlet temperature threshold, the fuel cell impedance threshold, the coolant pump speed threshold, the coolant pump outlet pressure change threshold, and the voltage change rate threshold, and the fuel cell impedance threshold includes a high-frequency impedance threshold and a low-frequency impedance threshold; and whether a leak occurs between the gas circuit and the coolant circuit is determined according to the actual operating parameters and the thresholds corresponding to the parameters.

2. The fuel cell leakage detection method according to claim 1, characterized in that: Whether the gas leaks into the coolant circuit is determined based on the coolant pump speed of the fuel cell, the coolant pump outlet pressure change value, the coolant circuit inlet and outlet temperature and temperature difference within a predetermined time period. The thresholds involved in the judgment process include: coolant pump speed threshold, coolant pump outlet pressure change threshold, and coolant circuit inlet and outlet temperature threshold.

3. The fuel cell leakage detection method according to claim 2, characterized in that: The specific process of judging whether the gas is leaking into the coolant line is as follows: S1: Acquire actual operating parameters and thresholds corresponding to the parameters during operation, the actual operating parameters include the speed of the coolant pump of the fuel cell, the change value of the coolant pump outlet pressure, the inlet and outlet temperatures and temperature difference of the coolant path; the acquired thresholds include the coolant pump speed threshold, the coolant pump outlet pressure change threshold, and the inlet and outlet temperature threshold of the coolant path; S2: When it is determined that the change value of the coolant pump outlet pressure within the predetermined time period is greater than the coolant pump outlet pressure change threshold, enter S3; S3: Determine whether the outlet temperature of the fuel cell increases to the outlet temperature threshold; if not, proceed to S7; if yes, proceed to S4; S4: Determine whether the coolant pump speed is reduced to the coolant pump speed threshold; if not, proceed to S7; if yes, proceed to S5; S5: Adjust the speed of the coolant pump to adjust the inlet and outlet temperatures to a normal range within the set temperature difference; S6: Determine whether the coolant pump speed is higher than the coolant pump speed threshold; if not, proceed to S7; if yes, proceed to S8; S7: Check the cause of the abnormality; end the operation; S8: It is determined that the gas has leaked into the coolant line, and the operation is terminated.

4. The fuel cell leakage detection method according to claim 1, characterized in that: Whether the coolant has leaked into the gas circuit is judged based on the voltage change rate, the hydrogen circuit inlet and outlet pressure drop, the air circuit inlet and outlet pressure drop, the fuel cell impedance value and the corresponding thresholds within a predetermined time period; the thresholds involved in whether the coolant has leaked into the gas circuit include the voltage change rate threshold, the hydrogen circuit inlet and outlet pressure drop threshold, the air circuit inlet and outlet pressure drop threshold, and the fuel cell impedance threshold.

5. The fuel cell leakage detection method according to claim 4, characterized in that: The specific process of whether the coolant leaks into the gas line is as follows: S1: Acquire actual operating parameters and thresholds during operation: voltage change rate, hydrogen path inlet and outlet pressure drop, air path inlet and outlet pressure drop, and fuel cell impedance value within a predetermined time period; the thresholds involved include voltage change rate threshold, hydrogen path inlet and outlet pressure drop threshold, air path inlet and outlet pressure drop threshold, and fuel cell impedance threshold (including high-frequency impedance threshold and low-frequency impedance threshold); S2: When it is determined that the voltage change rate within the predetermined time period is greater than the voltage change rate threshold, enter S3; S3: Determine whether the operating condition deviates from the set value: if the operating condition deviates from the set value, the operating condition is corrected. After the operating condition is corrected, if the voltage change rate changes within the threshold, the operation continues; if the operating condition does not deviate from the set value, enter S4; S4: Determine whether the pressure drop of the gas path inlet and outlet is greater than the corresponding threshold, and whether the high-frequency and low-frequency impedances are greater than the fuel cell impedance threshold; S5: Determine whether the increase in the hydrogen path inlet and outlet pressure drop exceeds the hydrogen path inlet and outlet pressure drop threshold, whether the high-frequency and low-frequency impedances increase, and whether the increase in the high-frequency impedance exceeds the fuel cell impedance threshold; if the hydrogen path inlet and outlet pressure drop increases and exceeds the hydrogen path inlet and outlet pressure drop threshold, whether the high-frequency and low-frequency impedances increase, and whether the high-frequency impedance increases and exceeds the fuel cell impedance threshold, then it is determined that the coolant path leaks to the hydrogen path; if not, enter S5; S6: If the air path inlet and outlet pressure drop increases and exceeds the air path inlet and outlet pressure drop threshold, the high-frequency and low-frequency impedances both increase, and the low-frequency impedance increases and exceeds the threshold, it is determined that the coolant path leaks to the hydrogen path; S7: End the operation after checking the abnormal cause, the coolant line leaks into the hydrogen line, or the coolant line leaks into the air line.

6. A fuel cell leakage detection device, characterized in that: The device comprises a control module (1), the control module (1) being connected to a storage module (2), a transmission module (3), an input module (4), an output module (5) and a controlled system (6), and the device acquires actual operating parameters and stores setting thresholds of various parameters.

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