Flow channel fault diagnosis method for cooling system of water-cooled hydrogen fuel cell

Abstract

The invention discloses a flow channel fault diagnosis method for a cooling system of a water-cooled hydrogen fuel cell. The flow channel fault diagnosis method comprises the following steps: collecting state data of a current fuel cell; predicting state parameters of the cooling system based on the collected current state data of the fuel cell; and judging whether the flow channel of the cooling system has a fault based on the predicted state parameters of the cooling system. The fuel cell cooling system fault diagnosis method has the advantages that the fault diagnosis accuracy of the fuel cell cooling system is improved, abnormity such as semi-blockage of the cooling liquid flow channel is recognized in advance, and local overtemperature caused by poor heat dissipation effect due to insufficient reactor entering flow is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of fuel cells, and in particular to a method for diagnosing flow channel faults in a cooling system of a water-cooled hydrogen fuel cell. Background Art

[0002] Hydrogen fuel cell systems have significant advantages such as low noise, zero emissions, and high energy conversion efficiency, and therefore have received widespread attention in the energy and power industry. In the actual application scenarios of fuel cell systems, it is crucial to control the temperature of the stack, because the stack temperature has a great impact on the system output performance, safety, durability, and life. When the operating temperature of the stack is too low, the impedance of the proton exchange membrane inside the stack will be large, resulting in low stack output performance; when the operating temperature of the stack is too high, it will affect the uniformity of the temperature field distribution of the proton exchange membrane inside the stack, and even local hot spots and overheating will occur, causing the proton membrane to dehydrate and cause long-term irreversible damage, and gradually rupture and other serious failures, ultimately leading to the adverse consequence that the entire system cannot output normally.

[0003] The temperature of the water-cooled fuel cell system is controlled by the cooling system. In addition to real-time monitoring of the system temperature, the controller also needs to precisely control actuators such as the electronic fan, electronic thermostat, and electronic water pump to keep the stack temperature at a reasonable level. More importantly, it is necessary to monitor and diagnose the phenomenon that the stack temperature may be too high, and enter the alarm, power limiting or shutdown processing process when necessary to protect the stack and the system.

[0004] Ordinary fuel cell cooling system fault diagnosis and control methods rely on the water temperature and water pressure sensors at the inlet and outlet of the fuel cell stack installed in the system. When the actual water pressure is low or high, and the water temperature exceeds the maximum value, a fault is reported. These diagnostic methods cannot identify and report faults in advance when the water temperature or water pressure has not completely exceeded the threshold. When the system flow channel is semi-blocked, the hysteresis effect of the water temperature and the large fluctuations in the pressure signal itself make it difficult for simple temperature and pressure diagnosis to timely and accurately identify the abnormality of non-complete blockage of the flow channel, which makes the system have the risk of overheating when operating at high power and high temperature conditions.

[0005] A hydrogen fuel cell is a system that converts chemical energy of hydrogen and oxygen into electrical energy and thermal energy through an electrochemical reaction. It is not limited by the Carnot cycle, has a high conversion efficiency, and can operate continuously for a long time as long as there is enough fuel gas. The fuel cell system is mainly composed of a stack, an air subsystem, a hydrogen subsystem, a cooling system, and an electronic control system.

[0006] There are two main methods for fuel cell cooling system fault diagnosis currently used:

[0007] 1. Diagnosis of the inlet and outlet water temperature of the fuel cell stack. The measured value of the inlet and outlet temperature sensor of the fuel cell stack is used as the input. When the actual temperature value or the inlet and outlet temperature difference reaches or exceeds the fault threshold of the reasonable temperature or temperature difference range and lasts for a certain period of time, the abnormal temperature fault of the fuel cell stack is triggered. The abnormal temperature fault is generally divided into multiple levels. After being triggered, the alarm, power limit and system shutdown are respectively carried out according to the fault level from low to high.

[0008] 2. Diagnosis of the inlet and outlet water pressure of the fuel cell stack uses the measured value of the inlet and outlet pressure sensor of the fuel cell stack as input. When the measured signal value reaches or exceeds the judgment threshold of the reasonable pressure range and lasts for a certain period of time, it triggers faults such as excessively low or excessively high pressure or too small inlet and outlet pressure difference. Abnormal pressure faults are generally divided into multiple levels. After being triggered, alarms, power limits, and system shutdowns are performed according to the fault level from low to high.

[0009] In the actual application of the above two methods, when the required operating temperature of the battery stack is high and close to the alarm temperature, the water temperature itself is likely to fluctuate. Therefore, if the water temperature threshold is increased, it is easy to over-temperature operation and damage the battery stack. If the water temperature threshold is lowered, it is easy to cause frequent over-temperature shutdowns, which has a greater impact on system operation. On the other hand, the change in water temperature itself has hysteresis. If there is a foreign object in the coolant flow channel and it is in a semi-blocked state, the coolant pressure does not change significantly, so that the pressure diagnosis fault reaches the trigger state, and the system will run for a long time in a state of insufficient heat dissipation. Because the actual measured value of the water temperature sensor at the outlet of the battery stack is distorted and cannot well represent the internal temperature of the battery stack, the fault diagnosis based on the actual pressure and temperature value exceeding the limit cannot fully play the role of protecting the battery stack, and has great limitations in actual applications. Summary of the invention

[0010] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for diagnosing flow channel faults in a water-cooled hydrogen fuel cell cooling system, thereby improving the accuracy of fuel cell cooling system fault diagnosis, identifying abnormalities such as semi-blockage of the coolant flow channel in advance, avoiding local overheating caused by poor heat dissipation due to insufficient flow into the stack, and minimizing the adverse effects of overheating on the durability and service life of the fuel cell stack and system.

[0011] In order to achieve the above object, the technical solution adopted by the present invention is: a method for diagnosing flow channel faults in a water-cooled hydrogen fuel cell cooling system, comprising:

[0012] Collect current fuel cell status data;

[0013] Predicting state parameters of the cooling system based on the collected current state data of the fuel cell;

[0014] It is determined whether a cooling system flow path is faulty based on the predicted state parameters of the cooling system.

[0015] The sensor components based on the fuel cell stack and cooling system collect the status data of the fuel cell, where the collected status data include the stack coolant inlet temperature, stack coolant inlet pressure, stack coolant outlet temperature, stack coolant outlet pressure, liquid level signal, water pump speed signal, risk speed, thermostat opening, stack current, stack voltage, and ambient temperature data.

[0016] Build a prediction model in advance and output the predicted values ​​of state parameters based on the prediction model.

[0017] The pre-built prediction models include the stack cooling hydraulic pressure drop model, the stack coolant flow model and the cooling system heat dissipation capacity model. The real-time collected status data are sent to the stack cooling hydraulic pressure drop model, the stack coolant flow model and the cooling system heat dissipation capacity model after signal filtering and anti-shake processing, and the predicted value of the stack outlet cooling water temperature, the estimated value of the stack outlet coolant pressure and the estimated value of the water temperature change rate are predicted and output.

[0018] Determining whether the cooling system flow path is faulty includes: comparing the actual value of the water temperature at the outlet of the fuel cell stack collected in real time with the maximum limit of the water temperature. When the actual value of the water temperature at the outlet of the fuel cell stack is greater than the maximum limit of the water temperature and lasts for a set time, it is determined to be a fault and a fault signal is output.

[0019] The predicted value of the cooling water temperature at the stack outlet, the predicted value of the coolant pressure at the stack outlet, and the predicted value of the water temperature change rate are compared with the predicted value limit. If any of the predicted value of the cooling water temperature at the stack outlet, the predicted value of the coolant pressure at the stack outlet, and the predicted value of the water temperature change rate exceeds the corresponding predicted value limit, it is diagnosed as a fault and a fault signal is output.

[0020] The predicted value of the cooling water temperature at the stack outlet, the estimated value of the coolant pressure at the stack outlet, and the estimated value of the water temperature change rate are compared with the actual measured value of the cooling water temperature at the stack outlet, the actual measured value of the coolant pressure at the stack outlet, and the actual water temperature change rate calculated based on the actual water temperature value. When the difference between the two is greater than the set difference threshold, a fault is diagnosed and a fault signal is output.

[0021] The working status of the fuel cell is collected in real time. When the fuel cell is in the preset working state, the corresponding liquid pressure and flow changes under the change of water pump speed are detected in real time, and whether a fault occurs is determined based on the pressure and flow changes.

[0022] The fault diagnosis active monitoring activation conditions are preset, and when the activation conditions are met, the fault diagnosis method is started to collect the current fuel cell status data.

[0023] The activation condition of the active fault diagnosis monitoring is the preset operating condition of the fuel cell system. When the fuel cell is in the preset operating condition, the active fault diagnosis monitoring is activated and the fuel cell is subjected to fault diagnosis.

[0024] The advantages of the present invention are: improving the accuracy of fuel cell cooling system fault diagnosis, identifying abnormalities such as semi-blockage of the coolant flow channel in advance, avoiding local overheating caused by poor heat dissipation due to insufficient flow into the stack, and minimizing the adverse effects of overheating on the durability and service life of the stack and system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The following is a brief description of the contents expressed in the drawings of the present invention and the symbols in the drawings:

[0026] Figure 1 It is a schematic diagram of the principle of the water cooling system of the fuel cell system;

[0027] Figure 2 It is a judgment flow chart of the fault diagnosis method of the present invention. DETAILED DESCRIPTION

[0028] The specific implementation of the present invention will be further explained in detail below by describing the optimal embodiment with reference to the accompanying drawings.

[0029] The present embodiment provides a diagnostic method for accurately and reliably judging a flow channel fault in a cooling system of a water-cooled hydrogen fuel cell. The fault is detected before the water temperature in the cooling system exceeds the limit value due to the flow channel fault, thereby avoiding delays in fault detection, detecting the fault in advance and giving an alarm in time. At the same time, multi-parameter fault detection is adopted to improve the accuracy and fault detection rate. The specific scheme is as follows:

[0030] This embodiment provides a method for diagnosing flow channel faults in a water-cooled hydrogen fuel cell cooling system, comprising the following steps:

[0031] S1, judgment on activation of active fault monitoring function; after the fuel cell is started, the working condition data of the fuel cell is detected in real time, and based on the working condition data, it is judged whether the conditions for activating the active monitoring function are met at this time. If so, step S2 is entered, otherwise, continuous monitoring is performed until the activation conditions are met and step S2 is entered. Activating the active fault monitoring function means that when it is detected that the working condition of the fuel cell meets the preset working condition, the fault monitoring function is started. The difference in the working condition of the fuel cell here is to judge the working condition at this time based on the collected state data of the fuel cell, such as the thermal engine working condition or other predetermined working condition. Each working condition can be judged by detecting the working state of the fuel cell, so it is possible to judge whether the active fault monitoring is met by the preset working condition. The active fault diagnosis monitoring activation condition is set in advance, and the fault diagnosis method is started when the activation condition is met to collect the status data of the current fuel cell. The active fault diagnosis monitoring activation condition is the preset working condition of the fuel cell system. When the fuel cell is in the preset working condition, the active fault diagnosis monitoring is activated and the fuel cell is fault diagnosed.

[0032] Step S2, after entering the active monitoring function, collect the current status data of the fuel cell; based on the sensor components of the fuel cell stack and the cooling system, collect the status data of the fuel cell, wherein the collected status data include the stack coolant inlet temperature, the stack coolant inlet pressure, the stack coolant outlet temperature, the stack coolant outlet pressure, the liquid level signal, the water pump speed signal, the risk speed, the thermostat opening, the stack current, the stack voltage, and the ambient temperature data.

[0033] Step S3, predicting the state parameters of the cooling system based on the collected current state data of the fuel cell; performing data processing through some prediction models and outputting prediction values; judging whether the cooling system flow path is faulty based on the predicted state parameters of the cooling system, pre-building a prediction model and outputting the state parameter prediction values ​​based on the prediction model.

[0034] The pre-built prediction models include the stack cooling hydraulic pressure drop model, the stack coolant flow model, and the cooling system heat dissipation capacity model. The real-time collected status data is sent to the stack cooling hydraulic pressure drop model, the stack coolant flow model, and the cooling system heat dissipation capacity model after signal filtering and anti-shake processing, and the predicted value of the stack outlet cooling water temperature, the stack outlet coolant pressure, and the water temperature change rate are predicted. The prediction model obtains the required model through multiple pre-test analyses, and the model is used to simulate the state of heat dissipation, flow changes, and liquid pressure changes, which can be completed through test calibration settings.

[0035] The predicted value and the measured value are analyzed to determine whether the cooling system flow path is faulty. The method for determining whether the cooling system flow path is faulty includes: comparing the actual value of the water temperature at the outlet of the fuel cell stack collected in real time with the maximum limit of the water temperature. When the actual value of the water temperature at the outlet of the fuel cell stack is greater than the maximum limit of the water temperature and lasts for a set time, it is determined to be a fault and a fault signal is output.

[0036] The predicted value of the cooling water temperature at the stack outlet, the predicted value of the coolant pressure at the stack outlet, and the predicted value of the water temperature change rate are compared with the predicted value limit. If any of the predicted value of the cooling water temperature at the stack outlet, the predicted value of the coolant pressure at the stack outlet, and the predicted value of the water temperature change rate exceeds the corresponding predicted value limit, it is diagnosed as a fault and a fault signal is output.

[0037] The predicted value of the cooling water temperature at the stack outlet, the estimated value of the coolant pressure at the stack outlet, and the estimated value of the water temperature change rate are compared with the actual measured value of the cooling water temperature at the stack outlet, the actual measured value of the coolant pressure at the stack outlet, and the actual water temperature change rate calculated based on the actual water temperature value. When the difference between the two is greater than the set difference threshold, a fault is diagnosed and a fault signal is output.

[0038] In a preferred embodiment, the working status of the fuel cell is collected in real time. When the fuel cell is in a preset working state, the corresponding changes in liquid pressure and flow rate under the change in water pump speed are detected in real time, and whether a fault occurs is determined based on the changes in pressure and flow rate. If the changes in liquid pressure and flow rate under the change in water pump speed are unreasonable, it is determined that a fault occurs. Here, there is a certain corresponding relationship between the change in water pump speed and the change in liquid pressure and flow rate. The corresponding relationship can be calibrated in advance, and the reasonable change state of liquid pressure and flow rate can be obtained through the change in water pump speed, and compared with the actual flow rate and pressure change state to determine whether it is reasonable, and then determine whether it is a fault.

[0039] The present invention is based on the operating mechanism and system composition of hydrogen fuel proton exchange membrane fuel cells, combined with a large amount of bench and system test data, and by analyzing the possible causes of different fault phenomena, a reasonable range or state judgment of data information based on the existing input signals of the system, including coolant inlet stack pressure and temperature, pressure sensor and outlet stack temperature, pressure, radiator outlet temperature, coolant level and other sensor signals, electronic thermostat, electronic water pump, electronic fan and other actuator feedback states, as well as heat release under specific test conditions of the stack, system heat dissipation calculation, etc., is proposed to estimate whether the temperature rise change of coolant in and out of the stack is reasonable under the current coolant flow rate and stack power, and further determine whether the flow rate and other states represented by the pressure difference change of the cooling system flow channel are too different from the normal state data, so as to perform fault diagnosis of cooling system flow channel semi-blockage and the like.

[0040] The main implementation ideas of this solution include:

[0041] 1. Design and build a model of heat release, heat dissipation and stack coolant flow rate of the fuel cell system. The model can eventually calculate the output stack coolant outlet temperature based on the current operating conditions of the system. The simplified model will be added to the system controller software model, and the stack outlet water temperature will be calculated and estimated in real time when the system is actually running.

[0042] 2. Design test cases under specific working conditions, set each actuator of the cooling system to a certain working state, and install a coolant flow meter on the system. Test and obtain the stack coolant flow, pressure, pressure difference and temperature difference in and out of the stack under normal conditions, and calculate the stack temperature change rate.

[0043] 3. Add a prediction model for the stack outlet temperature and required flow rate to the software of the fuel cell system controller, and calibrate the prediction model using the test data from step 2.

[0044] 4. When the system is actually running, it starts up and warms up according to the predetermined operating conditions. When the outlet temperature and change rate measured by the stack outlet temperature sensor, as well as the predicted values ​​of the inlet and outlet flow rates, continue to deviate from the reasonable range of the non-alarm range, it is considered that there is an abnormality in the cooling system pipeline and it is determined that an abnormal fault has occurred in the cooling system.

[0045] 5. Under specific test conditions of hot engine or lower temperature, the system controller can determine in advance that the flow path of the cooling system is abnormal because the water temperature at the outlet of the fuel cell stack changes or the flow rate in and out of the stack is lower than expected, without having to wait until the actual operating water temperature exceeds the tolerance threshold of the fuel cell stack, thereby minimizing the risk of irreversible losses caused by over-temperature operation of the fuel cell stack.

[0046] like Figure 1 As shown, this scheme is to detect the failure of the cooling system of the water-cooled fuel cell. Figure 1 That is, the water cooling system, which at least includes: a coolant temperature and pressure integrated sensor TPS, a deionizer I EF, an electronic thermostat ET, a particulate filter PF, an expansion water tank CT, a radiator outlet water temperature sensor T, a radiator RAD, a PTC heater PTC_W, and an electronic water pump CWP. The water cooling control of the fuel cell is achieved through interactive control between components.

[0047] Based on the free inlet and outlet pressure and temperature sensors of the system and the stack current and voltage sensors, the present invention obtains relevant parameters based on the free sensors, thereby designing a prediction model for the target flow rate and outlet water temperature of the stack coolant that combines the model and test data fitting. In actual operation, the predicted values ​​of the target water temperature and outlet water temperature under specific test conditions are compared with the reasonable values ​​obtained in advance. When the deviation is large, an abnormal fault of the cooling system flow channel is reported. Compared with the traditional fault diagnosis method based on the water temperature and water pressure values ​​exceeding the allowable upper limit, it has the following advantages:

[0048] 1. It can avoid the problem of low diagnostic accuracy when the pressure and pressure difference of the coolant in and out of the stack are simply relied on for diagnosis. The water circuit is affected and disturbed by actuators such as water pumps and thermostats, resulting in a large fluctuation range of the pressure signal, which leads to the pressure and pressure difference exceeding the allowable range limit.

[0049] 2. Based on specific test conditions, set fixed water pump speed, thermostat opening, stack power, etc., test and obtain reasonable stack inlet and outlet pressure, pressure difference, stack water temperature change rate and other data as benchmark values. During the actual operation of the system, purposefully carry out the cooling system test procedure to test the stack inlet and outlet pressure, pressure difference, stack water temperature change rate and other data under the corresponding conditions, and make accurate comparisons with the benchmark values ​​to identify and report abnormal faults of the cooling system in advance. There is no need to wait until the system actually runs to a higher temperature and exceeds the allowable upper limit before reporting an over-temperature fault, thereby minimizing the risk of untimely diagnosis of over-temperature faults caused by the hysteresis effect of water temperature and reducing the risk of over-temperature operation failures.

[0050] 3. Simple over-temperature and over-pressure failures cannot provide more detailed guidance information for subsequent fault cause analysis and location. The identification and triggering of abnormal cooling system failures can better locate the abnormal flow resistance of the cooling system flow channel, which can better improve system testing and after-sales maintenance, and the efficiency of analyzing, troubleshooting, locating and solving cooling system failures.

[0051] The present invention provides a fault diagnosis method for abnormal coolant flow channel of a proton exchange membrane fuel cell system. First, the characteristic values ​​of the inlet and outlet pressure, pressure difference and outlet water temperature change rate of the fuel cell stack under normal thermal engine or other specific working conditions are obtained through testing. The specific operation is: after the fuel cell system is started, the thermostat is closed, all the coolant goes through a small circulation, the water pump speed is set to a fixed value, the thermal engine power of the fuel cell stack is given a specific value, and the inlet and outlet pressure and pressure difference values ​​of the fuel cell stack, as well as the inlet and outlet pressure values ​​of the fuel cell stack are tested and recorded; a similar working condition is designed, the thermostat opening, water pump speed and fuel cell stack operating power are given, and the inlet and outlet pressure, pressure difference and temperature values ​​of the fuel cell stack are obtained through testing. These test values ​​are used as the basis for the final fault judgment.

[0052] Develop corresponding test and diagnosis function module software, which runs in the fuel cell system controller, and try to collect the current, voltage, water temperature, water pressure and other information when the system is running, and activate the cooling system abnormal fault diagnosis function at a reasonable time, collect, calculate and compare the corresponding data, and finally give the diagnosis result to determine whether there is any abnormality in the cooling system flow path.

[0053] The present invention provides a fault diagnosis method for abnormal flow path of a water-cooled hydrogen fuel cell cooling system. The implementation of the method is divided into the following three steps:

[0054] Step 1, Experimental design and data acquisition: Through experiments, various data parameters of the fuel cell and water cooling system are obtained to provide basic parameters for the model building in STEP 2.

[0055] Step 2. Build models for the stack flow rate and outlet water temperature: Build models based on various parameter data from the experimental process. Use mathematical models to establish mathematical relationships between parameters of the fuel cell system or predict some parameters through models. The model is designed through experimental calibration and can be built using neural network models, big data models, or based on collected data and system principles.

[0056] Step 3, abnormal water temperature fault diagnosis method, based on this method, the fault diagnosis is designed, and the actual measured data and estimated data of the water cooling system in the actual operation process are comprehensively analyzed to determine whether there is a fault or not, including:

[0057] The input signals for fault judgment include:

[0058] 1. Sensor physical quantity: stack cooling path inlet and outlet temperature, pressure sensor, liquid level sensor

[0059] 2. Actuator feedback information message: electronic water pump, thermostat, fan

[0060] 3. The fault diagnosis mechanism of physical quantities such as stack voltage, stack current, and ambient temperature that affect the changes in heat and temperature fields includes:

[0061] 1. The actual value of the input signal reaches the fault judgment threshold, and the duration reaches the target value, triggering the fault

[0062] 2. The water temperature, heat release, and heat dissipation at the stack outlet predicted by data fitting meet the abnormal judgment conditions and trigger the fault

[0063] 3. The difference between the predicted value and the actual value is too large, reaching the judgment condition and triggering the fault

[0064] 4. Set the cooling system flow active detection function, activate this function under specific working conditions such as system self-check or hot engine, detect unreasonable changes in pressure and flow at different pump speeds, and trigger a fault

[0065] 5. Set the system temperature rise monitoring function, run this function when the system is hot or at other predetermined operating points, monitor the unreasonable change rate of the stack water temperature, and trigger a fault

[0066] Compared with the prior art, the diagnostic method described in the present invention has the following outstanding advantages: before the actual temperature reaches the temperature threshold that the fuel cell stack can actually tolerate, the abnormal condition of the cooling pipeline is determined to avoid temperature anomalies caused by the impact on the cooling capacity; and guidance information is provided for system maintenance and fault analysis and positioning.

[0067] The present invention improves the accuracy of fuel cell cooling system fault diagnosis, identifies anomalies such as semi-blockage of the coolant flow channel in advance, avoids local overheating caused by poor heat dissipation due to insufficient flow into the stack, and minimizes the adverse effects of overheating on the durability and service life of the stack and system.

[0068] Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, they are all within the protection scope of the present invention.

Claims

1. A method for diagnosing flow channel faults in a water-cooled hydrogen fuel cell cooling system, characterized in that: include: Collect current fuel cell status data; Predicting state parameters of the cooling system based on the collected current state data of the fuel cell; It is determined whether a cooling system flow path is faulty based on the predicted state parameters of the cooling system.

2. A method for diagnosing flow channel faults in a water-cooled hydrogen fuel cell cooling system as claimed in claim 1, characterized in that: The sensor components based on the fuel cell stack and cooling system collect the status data of the fuel cell, where the collected status data include the stack coolant inlet temperature, stack coolant inlet pressure, stack coolant outlet temperature, stack coolant outlet pressure, liquid level signal, water pump speed signal, risk speed, thermostat opening, stack current, stack voltage, and ambient temperature data.

3. A method for diagnosing flow path faults in a water-cooled hydrogen fuel cell cooling system as claimed in claim 1, characterized in that: Build a prediction model in advance and output the predicted values ​​of state parameters based on the prediction model.

4. A method for diagnosing flow path faults in a water-cooled hydrogen fuel cell cooling system as claimed in claim 3, characterized in that: The pre-built prediction models include the stack cooling hydraulic pressure drop model, the stack coolant flow model and the cooling system heat dissipation capacity model. The real-time collected status data are sent to the stack cooling hydraulic pressure drop model, the stack coolant flow model and the cooling system heat dissipation capacity model after signal filtering and anti-shake processing, and the predicted value of the stack outlet cooling water temperature, the estimated value of the stack outlet coolant pressure and the estimated value of the water temperature change rate are predicted and output.

5. A method for diagnosing flow path faults in a water-cooled hydrogen fuel cell cooling system as claimed in claim 4, characterized in that: Determining whether the cooling system flow path is faulty includes: comparing the actual value of the water temperature at the outlet of the fuel cell stack collected in real time with the maximum limit of the water temperature. When the actual value of the water temperature at the outlet of the fuel cell stack is greater than the maximum limit of the water temperature and lasts for a set time, it is determined to be a fault and a fault signal is output.

6. A method for diagnosing flow path faults in a water-cooled hydrogen fuel cell cooling system as claimed in claim 4, characterized in that: The predicted value of the cooling water temperature at the stack outlet, the predicted value of the coolant pressure at the stack outlet, and the predicted value of the water temperature change rate are compared with the predicted value limit. If any of the predicted value of the cooling water temperature at the stack outlet, the predicted value of the coolant pressure at the stack outlet, and the predicted value of the water temperature change rate exceeds the corresponding predicted value limit, it is diagnosed as a fault and a fault signal is output.

7. A method for diagnosing flow path faults in a water-cooled hydrogen fuel cell cooling system as claimed in claim 4, characterized in that: The predicted value of the cooling water temperature at the stack outlet, the estimated value of the coolant pressure at the stack outlet, and the estimated value of the water temperature change rate are compared with the actual measured value of the cooling water temperature at the stack outlet, the actual measured value of the coolant pressure at the stack outlet, and the actual water temperature change rate calculated based on the actual water temperature value. When the difference between the two is greater than the set difference threshold, a fault is diagnosed and a fault signal is output.

8. A method for diagnosing flow path faults in a water-cooled hydrogen fuel cell cooling system according to any one of claims 1 to 7, characterized in that: The working status of the fuel cell is collected in real time. When the fuel cell is in the preset working state, the corresponding liquid pressure and flow changes under the change of water pump speed are detected in real time, and whether a fault occurs is determined based on the pressure and flow changes.

9. A method for diagnosing flow path faults in a water-cooled hydrogen fuel cell cooling system as claimed in claim 8, characterized in that: The fault diagnosis active monitoring activation conditions are preset, and when the activation conditions are met, the fault diagnosis method is started to collect the current fuel cell status data.

10. A method for diagnosing flow path faults in a water-cooled hydrogen fuel cell cooling system as claimed in claim 9, characterized in that: The activation condition of the active fault diagnosis monitoring is the preset operating condition of the fuel cell system. When the fuel cell is in the preset operating condition, the active fault diagnosis monitoring is activated and the fuel cell is subjected to fault diagnosis.

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