A control method for eliminating high potential during start and stop of fuel cell and fuel cell system

Abstract

The application provides a control method for eliminating high potential of fuel cell start-stop, comprising: obtaining the stack operation state of a fuel cell system, obtaining the cathode potential data of the stack under the start condition and the shutdown condition based on the operation state; judging whether the fuel cell system is in a high potential state according to the cathode potential data, and triggering a recovery module to perform a high potential elimination operation if the fuel cell system is in the high potential state. The stack is monitored in real time, and the working condition of the fuel cell is dynamically adjusted, so that the purpose of reducing the cathode high potential condition is achieved, and the fuel cell stack can work efficiently for a long time. The occurrence of the cathode high potential is reduced by controlling the adjustable load element, and the carbon corrosion problem is further inhibited; the occurrence of the high potential is reduced, so that the attenuation of the fuel cell performance caused by the carbon corrosion under the high potential condition is reduced, and the service life of the fuel cell is prolonged.

Description

Technical Field

[0001] This invention relates to the field of fuel cell control technology, and in particular to a control method and fuel cell system for eliminating high potential during fuel cell start-up and shutdown. Background Technology

[0002] Fuel cell stacks mainly consist of proton exchange membranes, catalyst layers, gas diffusion layers, bipolar plates, and seals. Over long-term use, stack performance degrades, necessitating performance restoration to extend lifespan. For Pt / C catalyst layers, the direct cause of performance degradation is the reduction in the active surface area. Impurities in the reaction gas and high-potential, strongly oxidizing environments can promote the formation of a platinum oxide (PtOx) layer on the Pt catalyst, reducing the active surface area. Furthermore, the high cathode potential during start-up and shutdown can lead to corrosion of the carbon support in the catalyst layer. This corrosion causes the Pt catalyst adhering to it to be lost or migrated, further reducing the active surface area of ​​the catalyst layer.

[0003] Considering the application scenarios, fuel cell systems will continuously experience start-up and shutdown conditions and constantly cycle through high and low potentials when used at the end. As a result, the lifespan of the fuel cell stack at the end is basically greatly reduced.

[0004] Therefore, proposing a control method to reduce the performance degradation of fuel cell systems under high-potential conditions such as startup and shutdown is of great significance for extending the service life of fuel cell systems. Summary of the Invention

[0005] This invention provides a control method and fuel cell system for eliminating high potential during fuel cell start-up and shutdown, thereby reducing performance degradation of the fuel cell system under high potential conditions such as start-up and shutdown.

[0006] This invention provides a control method for eliminating high potential during fuel cell start-up and shutdown, comprising: Obtain the stack operating status of the fuel cell system, and obtain cathode potential data of the stack under start-up and shutdown conditions based on the operating status; The system is determined to be in a high-potential state based on the cathode potential data. If it is in a high-potential state, the recovery module is triggered to perform a high-potential elimination operation.

[0007] Preferably, the voltage, current, temperature, and humidity data of the fuel cell stack are collected to determine the operating conditions of the fuel cell stack; based on the voltage data, it is determined whether the cathode potential exceeds a preset threshold; if the cathode potential exceeds the preset threshold, it is determined that the fuel cell stack is in a high-potential state. Based on the cathode potential data, it is determined whether the high potential occurs during startup or shutdown; the recovery module eliminates the high potential during startup and shutdown by using load elements.

[0008] Preferably, when the fuel cell system is in startup mode, the following steps are taken: when a startup command is issued and the startup preset conditions are met, the switching element in the recovery module is closed, the load element is connected to both ends of the fuel cell stack, and the fuel cell stack voltage decreases; after the DC / DC module has started up, the switching element is opened; wherein, the startup preset conditions are that the single cell voltage of the fuel cell stack is greater than a preset value or the startup time reaches a preset time.

[0009] Preferably, when the fuel cell system is in a shutdown condition, the following steps are taken: when a shutdown command is issued and the DC / DC module is turned off, the switching element in the recovery module is closed, the load element is connected to both ends of the fuel cell stack, and the fuel cell stack voltage decreases; when the shutdown preset condition is met, the switching element is opened; wherein, the shutdown preset condition is that the voltage of a single cell in the fuel cell stack is less than a preset value two or the shutdown time reaches a preset time two.

[0010] Preferably, when the start command for starting the fuel cell system is issued, the following steps are included: The thermal management system is activated to maintain the fuel cell stack temperature within a preset range; When the hydrogen system is started, hydrogen is delivered to the anode of the fuel cell stack. When the preset start-up conditions are met, the switching element closes, the load element is connected to both ends of the fuel cell stack, and the voltage of a single cell in the fuel cell stack drops below the preset voltage. The preset start-up conditions are that the voltage of a single cell in the fuel cell stack is greater than the preset value or the start-up time reaches the preset time. The air system is activated, and air enters the cathode of the fuel cell stack, reacting with the hydrogen at the anode to ensure that the cathode air pressure meets the operating conditions of the fuel cell stack.

[0011] When the DC / DC module starts up, the switching elements are disconnected, the load elements are disconnected from both ends of the fuel cell stack, and the fuel cell stack charges the auxiliary power supply module and provides power to the load circuit.

[0012] Preferably, when a shutdown command to shut down the fuel cell system is issued, the following steps are included: the DC / DC module is shut down, the switching element is closed, the load element is connected to both ends of the fuel cell stack, and the air system is shut down in the next step; When the voltage of the fuel cell stack drops to the preset shutdown condition, the switching element is disconnected and the connection between the load element and the two ends of the fuel cell stack is disconnected. The preset shutdown condition is that the voltage of a single cell in the fuel cell stack is less than a preset value of two or the shutdown time reaches a preset time of two. The hydrogen system shuts down; then, when the stack temperature drops to a safe target temperature, the thermal management system shuts down, and the fuel cell system shutdown is complete.

[0013] Preferably, the first preset value is 0.85V and the first preset time is 2 seconds; the second preset value is 0.85V and the second preset time is 15 seconds; the load element is an adjustable load, and further, the adjustable load is an adjustable transient discharge load.

[0014] Preferably, the microscopic distribution data of the voltage of a single cell is collected from inside the fuel cell stack, and the collected voltage signal is processed to obtain voltage distribution data; The dynamic fluctuation trend is detected based on the obtained voltage distribution data; when the load changes abruptly, the voltage rise of each single cell is quantified to determine the peak position and duration of the fluctuation trend; if the determined peak value of the fluctuation trend exceeds the preset threshold, the anomaly marking module is activated to evaluate the correlation between the marked single cell position and the voltage deviation of the adjacent single cells, and obtain the deviation correlation index. Highly correlated regions are extracted from the obtained deviation correlation index. The triggering threshold of the switching element is adjusted according to the preset optimization model to match the response time requirement of the region, and the optimized threshold parameter set is determined. Based on the threshold parameter set, the stack operation scenario is simulated, and the local high potential accumulation in the simulation is iteratively suppressed to obtain the simulation result of the suppressed potential distribution. The potential damage risk distribution of the electrolyte membrane is obtained from the simulation results of the suppressed potential distribution. Based on the risk distribution, the full-link data from signal acquisition to control execution is integrated to determine the link coordination parameters. According to the determined link coordination parameters, the updated instructions are input to the actual stack control system. The link coordination parameters are applied in real time during dynamic operation to obtain the optimized voltage management execution sequence. The voltage management execution sequence is used to generate control battery instructions.

[0015] The present invention also provides a fuel cell system, which uses a control method to eliminate the high potential during fuel cell start-up and shutdown for system control, comprising: A fuel cell stack is used to generate electrical energy through an electrochemical reaction between hydrogen and oxygen in the air. The generated electrical energy powers the load module, i.e., it powers the user. The controller is used for dynamic monitoring of the real-time status of the fuel cell stack, recovery module, auxiliary power supply module, DC / DC module and user load, as well as for controlling the operation of the switching elements of the fuel cell stack, recovery module, auxiliary power supply module and DC / DC module; The recovery module is used to reduce the performance degradation of the fuel cell stack under startup and shutdown conditions, including load elements and switching elements; The auxiliary power supply module is used to store the electrical energy generated by the fuel cell stack to assist the fuel cell stack in providing power to the user load when the output is high. It is also used to provide initial energy for the entire system to start the system. The auxiliary power supply module can be either a lithium battery or a supercapacitor. DC / DC modules are used to convert the voltage of the fuel cell stack into a stable voltage that matches the user's load. One end of the user load is connected to the positive output of the DC / DC module, and the other end of the user load is connected to the negative output of the DC / DC module. The positive terminal of the fuel cell stack is connected to the positive input terminal of the DC / DC module, and the negative terminal of the fuel cell stack is connected to the negative input terminal of the DC / DC module. One end of the recovery module is connected to the positive terminal of the fuel cell stack, and the other end of the recovery module is connected to the negative terminal of the fuel cell stack. The auxiliary power supply module is connected in parallel with the user load.

[0016] The working principle and beneficial effects of this invention are as follows: This invention provides a control method for eliminating high potential during fuel cell start-up and shutdown, comprising: acquiring the stack operating status of the fuel cell system; obtaining cathode potential data of the stack under start-up and shutdown conditions based on the operating status; determining whether the fuel cell system is in a high potential state based on the cathode potential data; and triggering a recovery module to perform a high potential elimination operation if the system is in a high potential state.

[0017] This invention solves the problem of carbon corrosion of the catalyst layer caused by high potential in fuel cell systems during startup and shutdown, as well as the problem of carbon corrosion and battery performance degradation caused by high cathode potential. Specifically, this invention monitors the fuel cell stack in real time and dynamically adjusts the operation of the fuel cell based on the monitoring results, thereby reducing the high cathode potential and enabling the fuel cell stack to operate efficiently for a long time.

[0018] Furthermore, this invention collects physical data such as voltage, current, temperature, and humidity of the fuel cell stack; based on the collected physical data, it monitors the cathode potential of the fuel cell stack and determines whether it exceeds a preset value. If it exceeds the preset value, it triggers the recovery module to eliminate the high potential. By controlling the adjustable load element, the occurrence of cathode high potential is reduced, further suppressing carbon corrosion. By reducing the occurrence of high potential, the performance degradation of fuel cell caused by carbon corrosion under high potential conditions is reduced, thus extending the service life of the fuel cell.

[0019] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1This is a schematic diagram of the system structure of the present invention.

[0022] Figure 2 This is a schematic diagram of the connection of the recovery module of the present invention. Detailed Implementation

[0023] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0024] Chinese patent CN116141970A discloses a fuel cell system and control method with active and passive high-potential protection functions. This patent proposes a control method that achieves high-potential protection in case of abnormalities in the low-voltage power supply system of the fuel cell by setting up active and passive protection branches. While this method can protect the fuel cell from high-potential effects to a certain extent, it still has shortcomings in practical applications. The system has low cohesion, resulting in the derivation of two branches to jointly achieve the high-potential protection function.

[0025] Chinese patent CN113169359B proposes a method for reducing carbon corrosion in fuel cell stacks and related motor vehicles. This patent describes a method to reduce carbon corrosion by detecting the sealing performance of the cathode chamber of the fuel cell stack. It targets carbon corrosion caused by the hydrogen-air interface, particularly the hydrogen-air interface that appears after the fuel cell system has been inactive for an extended period. The specific method involves calculating the time interval based on the detected sealing performance, i.e., when hydrogen needs to be re-supplyed to avoid / reduce carbon corrosion, thereby preventing excessive oxygen accumulation in the anode chamber. This method requires re-supplying hydrogen to the anode chamber after prolonged system inactivity (e.g., shutdown), increasing system hydrogen consumption, energy consumption, and costs. Furthermore, the extended hydrogen content time in the anode chamber after prolonged system inactivity (e.g., shutdown) necessitates more stringent system safety design.

[0026] In existing technologies, carbon corrosion caused by the anode hydrogen-oxygen interface (resulting in high cathode potential) during fuel cell startup and shutdown processes leads to a decline in fuel cell performance.

[0027] Based on the above-mentioned technical problems, this invention proposes an improved control method that prevents the generation of high potentials during system startup and shutdown, thereby reducing the performance degradation caused by high potentials. Figures 1-2 As shown, this is reflected in: During startup: When the startup command is issued and the startup preset conditions are met, the switching element in the recovery module is closed, the load element is connected to both ends of the fuel cell stack, and the fuel cell stack voltage decreases. After the DC / DC startup is completed, the switching element is opened. The startup preset conditions are that the single cell voltage of the fuel cell stack is greater than a preset value or the startup time reaches a preset time.

[0028] When shutting down: When a shutdown command is issued, the switching element in the recovery module is closed when the DC / DC converter is turned off. The load element is connected to both ends of the fuel cell stack, and the fuel cell stack voltage decreases. When the preset shutdown conditions are met, the switching element is opened. The preset shutdown conditions are that the voltage of a single fuel cell stack is less than a preset value of two or the shutdown time reaches a preset time of two.

[0029] More specifically, according to Figure 1 As shown, this embodiment of the invention provides a control method for eliminating high potential during fuel cell start-up and shutdown, including: acquiring the stack operating status of the fuel cell system; obtaining cathode potential data of the stack under start-up and shutdown conditions based on the operating status; determining whether the fuel cell system is in a high potential state based on the cathode potential data; and triggering a recovery module to perform a high potential elimination operation if the system is in a high potential state.

[0030] The system collects voltage, current, temperature, and humidity data of the fuel cell stack to determine its operating conditions. Based on the voltage data, it determines whether the cathode potential exceeds a preset threshold. If the cathode potential exceeds the preset threshold, the system determines that the fuel cell stack is in a high-potential state. Based on the cathode potential data, it determines whether the high potential occurs during startup or shutdown. The system uses a recovery module to eliminate the high potential under startup and shutdown conditions through load elements.

[0031] When the fuel cell system is in startup mode, the following steps are taken: when a startup command is issued and the preset startup conditions are met, the switching element in the recovery module is closed, the load element is connected to both ends of the fuel cell stack, and the fuel cell stack voltage decreases; after the DC / DC module has started up, the switching element is opened; wherein, the preset startup conditions are that the voltage of a single cell in the fuel cell stack is greater than a preset value or the startup time reaches a preset time.

[0032] When the fuel cell system is in shutdown condition, the following steps are taken: when a shutdown command is issued and the DC / DC module is turned off, the switching element in the recovery module is closed, the load element is connected to both ends of the fuel cell stack, and the fuel cell stack voltage decreases; when the shutdown preset conditions are met, the switching element is opened; wherein, the shutdown preset conditions are that the voltage of a single cell in the fuel cell stack is less than a preset value of two or the shutdown time reaches a preset time of two.

[0033] When the start command for starting the fuel cell system is issued, the following steps are included: the start command is issued, the switch element in the recovery module is closed when the preset start conditions are met, the load element is connected to both ends of the stack, the stack voltage decreases, and the switch element is opened after the DC / DC start is completed. The preset start conditions are that the single cell voltage of the stack is greater than a preset value or the start time reaches a preset time.

[0034] Specifically, when the start-up command for the fuel cell system is issued, the following steps are included: the thermal management system is activated to maintain the stack temperature within a preset range; the hydrogen system is activated, hydrogen is supplied to the stack anode, and when the preset start-up conditions are met, the switching element closes, the load element is connected to both ends of the stack, and the single-cell voltage of the stack drops below a preset voltage. The preset start-up conditions are that the single-cell voltage of the stack is greater than a preset value or the start-up time reaches a preset time; the air system is activated, air enters the stack cathode and reacts with the hydrogen at the anode to ensure that the cathode air pressure meets the stack's operating conditions; the DC / DC module is activated, the switching element opens, the load element is disconnected from both ends of the stack, and the stack charges the auxiliary power supply module and provides power to the load circuit; wherein, the preset value is 0.85V and the preset time is 2 seconds.

[0035] When a shutdown command to shut down the fuel cell system is issued, the following steps are included: the DC / DC module is shut down, the switching element in the recovery module is closed, the load element is connected to both ends of the fuel cell stack, the fuel cell stack voltage decreases, and when the shutdown preset conditions are met, the switching element is disconnected. The shutdown preset conditions are that the voltage of a single cell in the fuel cell stack is less than a preset value of two or the shutdown time reaches a preset time of two.

[0036] Specifically, when the shutdown command for the fuel cell system is issued, the following steps are included: the DC / DC module is shut down, the switching element is closed, and the load element is connected to both ends of the fuel cell stack; in the next step, the air system is shut down; when the fuel cell stack voltage drops to the shutdown preset condition, the switching element is opened, and the connection between the load element and both ends of the fuel cell stack is disconnected. The shutdown preset condition is that the single cell voltage of the fuel cell stack is less than a preset value two or the shutdown time reaches a preset time two; the hydrogen system is shut down; then, when the fuel cell stack temperature drops to a safe target temperature, the thermal management system is shut down, and the fuel cell system shutdown is completed; the preset value two is 0.85V, and the preset time two is 15 seconds; the load element is an adjustable load, and further, the adjustable load is an adjustable transient discharge load.

[0037] In this invention, the fuel cell system is started up using a control method, and the start-up process includes the following steps: 1) The command to start the fuel cell system is issued.

[0038] 2) First, the thermal management system is turned on to maintain the stack temperature within a safe and efficient range.

[0039] 3) In the next step, the hydrogen system is started, and hydrogen is delivered to the anode of the fuel cell stack. When the preset start-up conditions are met, the switching element closes, the load element is connected to both ends of the fuel cell stack, and the voltage of a single cell in the fuel cell stack drops below 0.85V. The preset start-up conditions are that the voltage of a single cell in the fuel cell stack is greater than a preset value or the start-up time reaches a preset time.

[0040] 4) Then the air system is started, and air enters the cathode of the fuel cell stack and reacts with the hydrogen at the anode.

[0041] 5) In the next step, the DC / DC converter starts up, the switching elements are disconnected, the load elements are disconnected from both ends of the fuel cell stack, and the fuel cell stack charges the auxiliary power supply module and provides power to the load circuit.

[0042] 6) The preset value of 0.85V and the preset time of 2s are applied to the above steps.

[0043] In this invention, the fuel cell system is shut down using a control method, and the shutdown process includes the following steps: 1) The command to shut down the fuel cell system is issued.

[0044] 2) When a shutdown command to shut down the fuel cell system is issued, the following steps are included: DC / DC is turned off, switching elements are closed, load elements are connected to both ends of the fuel cell stack, and the air system is turned off in the next step.

[0045] 3) When the voltage of the fuel cell gradually decreases and the preset shutdown conditions are met, the switching element is disconnected and the connection between the load element and the two ends of the fuel cell is disconnected. The preset shutdown conditions are that the voltage of a single cell in the fuel cell is less than a preset value of two or the shutdown time reaches a preset time of two.

[0046] 4) Then, in the next step, the hydrogen system is shut down.

[0047] 5) Finally, when the stack temperature drops to a safe target temperature, the thermal management system shuts down, and the fuel cell system shutdown is complete.

[0048] 6) For the fuel cell stack, preset value two is 0.85V and preset time two is 15s, which are applied to the above steps.

[0049] This invention solves the problem of carbon corrosion of the catalyst layer caused by high potential in fuel cell systems during startup and shutdown, as well as the problem of carbon corrosion and battery performance degradation caused by high cathode potential. Specifically, this invention monitors the fuel cell stack in real time and dynamically adjusts the operation of the fuel cell based on the monitoring results, thereby reducing the high cathode potential and enabling the fuel cell stack to operate efficiently for a long time.

[0050] Furthermore, this invention collects physical data such as voltage, current, temperature, and humidity of the fuel cell stack; based on the collected physical data, it monitors the cathode potential of the fuel cell stack and determines whether it exceeds a preset value. If it exceeds the preset value, it triggers the recovery module to eliminate the high potential. By controlling the adjustable load element, the occurrence of cathode high potential can be reduced, thereby further suppressing carbon corrosion. Furthermore, by reducing the occurrence of high potential, the performance degradation of fuel cell caused by carbon corrosion under high potential conditions can be reduced, thus extending the service life of the fuel cell.

[0051] In one embodiment, microscopic distribution data of the voltage of a single cell is collected from inside the fuel cell stack. Voltage signals are extracted from the collected microscopic distribution data and processed to obtain voltage distribution data. The original voltage signal includes microscopic distribution data and environmental noise interference data.

[0052] In this embodiment, firstly, the original voltage signals of each cell inside the fuel cell stack are collected. An environmental impact model is established based on the humidity change parameters and temperature change parameters collected by the temperature and humidity sensors. If the ambient humidity exceeds a preset threshold, the sensing accuracy compensation coefficient is adjusted. If the temperature change amplitude is greater than the reference value, the voltage measurement baseline is corrected. The original voltage signal is filtered, and the filtering parameters are dynamically adjusted based on the environmental impact model to obtain a noise-suppressed voltage signal. The stability of the noise-suppressed voltage signal obtained after filtering is evaluated. If the signal fluctuation variance is less than the stability threshold, the signal is determined to be stable. If the signal fluctuation variance exceeds the stability threshold, the filtering process is repeated. A stable voltage signal is obtained through multiple evaluations.

[0053] A voltage distribution matrix for each battery is constructed using a stable voltage signal. The voltage values ​​at the gaps in the sensor array are filled using an interpolation algorithm to obtain complete microscopic voltage distribution data. The local voltage gradient and distribution uniformity in the voltage distribution matrix are analyzed. If the local voltage gradient value exceeds the abnormal threshold, it is marked as abnormal, and voltage distribution characteristic data with abnormality identification is obtained. A microscopic distribution map of cell voltage in a fuel cell stack is generated based on voltage distribution characteristic data with anomaly indicators. The battery voltage micro-distribution map includes the voltage values ​​of each battery and information on abnormal areas.

[0054] In this invention, by setting a voltage sensor inside the fuel cell, the voltage of each of its constituent cells can be collected in real time, thereby enabling better control over its operating state and voltage changes.

[0055] When there are large fluctuations in ambient temperature and / or relative humidity (e.g., excessively high or low temperature / humidity), the raw voltage signal may become inaccurate due to changes in temperature and humidity.

[0056] In this invention, an environmental impact model is established based on humidity and temperature change parameters collected by a temperature and humidity sensor. The original voltage signal is then corrected based on this model to ensure the accuracy and continuity of the data.

[0057] For example, when the temperature value exceeds the preset optimal operating range, and changes by 2°C, the range of the filter parameter α value is adjusted. When the humidity value exceeds the preset optimal operating range, the β value range is adjusted for every 5% change, thereby obtaining high-precision voltage distribution data.

[0058] In one embodiment, voltage distribution data is used to analyze dynamic fluctuation trends; when the load changes abruptly, the voltage rise of each battery is quantified to determine the location and duration of the fluctuation trend peak. If the peak value of the fluctuation trend exceeds the preset threshold, an anomaly is marked. The voltage deviation between the battery with the anomaly mark and its adjacent batteries is calculated. Based on the deviation calculation, the battery deviation correlation degree is obtained, and the deviation correlation degree index is obtained.

[0059] In this embodiment, the real-time voltage data of each battery is filtered and denoised to obtain a standardized voltage data sequence.

[0060] Dynamic features are extracted from standardized voltage data sequences, and voltage change patterns at load abrupt changes are identified to determine the starting time and magnitude of battery voltage rise.

[0061] The fluctuation trend parameters for each individual cell are calculated based on the starting time and magnitude of the voltage increase. These parameters include the peak position coordinates and duration. This yields the trend quantification results. If the peak position coordinates in the trend quantification results exceed the preset value, the physical location corresponding to the battery will be marked and an abnormal battery location list will be generated.

[0062] Based on the list of abnormal battery locations, the voltage deviation data of the abnormal battery and its adjacent batteries are extracted, and a deviation data matrix is ​​constructed. The deviation data matrix is ​​then used to analyze the correlation of deviations.

[0063] The correlation strength of voltage deviation between abnormal single cells and adjacent single cells is quantitatively calculated on the deviation data matrix to obtain the deviation correlation index value; based on the deviation correlation index value, a mapping table of the battery abnormality impact range is constructed.

[0064] Furthermore, a time series database was established for the collected battery voltage data to obtain voltage data sequences and calculate voltage change rates. The fluctuation trends of the corresponding battery voltage and change rates when the load suddenly changes from low to high were identified. Next, based on the first-order and second-order differences, the sampling point location, corresponding time, peak voltage, and duration of the fluctuation trend peak are calculated; if the peak exceeds the preset threshold, an anomaly is marked and the corresponding battery is marked.

[0065] The correlation between the voltage deviation of the marked abnormal battery and the adjacent normal battery is calculated; the voltage deviation sequence of the abnormal battery and the adjacent battery during the abnormal period is obtained, and the correlation coefficient (deviation correlation index) is obtained based on the voltage deviation sequence. The correlation coefficient is used to determine whether there is a positive correlation; if the comprehensive score of the deviation correlation index exceeds the preset correlation threshold, the abnormality is confirmed to be risky.

[0066] In one embodiment, a highly correlated region is extracted from the deviation correlation index, and the triggering threshold of the switching element is adjusted using an optimization model to match the response time of the highly correlated region. Based on the matching result, an optimized set of threshold parameters is determined.

[0067] The stack operation scenario is simulated using a threshold parameter set. High potentials that occur during the simulation are iteratively suppressed to obtain the simulation results of the suppressed potential distribution.

[0068] In this embodiment, when the fuel cell stack is running, sensors are used to collect potential data and response time data from multiple monitoring points. Based on the collected data, the deviation correlation index of each monitoring point is calculated to obtain a correlation matrix. Regions exceeding the correlation threshold in the correlation matrix are extracted and sorted by weight. The spatial coordinate range and corresponding response time requirement parameters of the highly correlated regions are extracted. Based on the spatial coordinate range and response time requirements, an optimization model is constructed. Among them, the response time requirement of the highly correlated region is used as a constraint to optimize the triggering threshold of the switching element, thereby determining the optimal set of threshold parameters; The control parameters of the feedback control algorithm are configured according to the determined set of threshold parameters, and a simulation model of the stack operation scenario is established again to obtain the initial potential distribution state. If there is an accumulated region in the initial potential distribution state where the local potential value exceeds the safety threshold, then iterative suppression is performed, and the control signal strength of the corresponding region is adjusted. The potential distribution changes are continuously monitored. If the detected cumulative potential value drops to a safe range, the current potential distribution result is recorded and used as the suppression optimization result. The potential distribution results generated through multiple iterations are used to generate the final stack operation status assessment report and optimization parameter recommendations.

[0069] The correlation coefficient of the deviation is calculated. When the correlation coefficient between the stack voltage deviation sequence and the ideal response sequence is greater than the preset value, it is identified as a high correlation region. At this time, the response time in the region is required to be within 15 milliseconds. Based on the particle swarm optimization algorithm, an optimization model for the trigger threshold of switching elements is constructed, and the search range for the trigger threshold of switching elements is determined. The system response performance under different threshold combinations is evaluated by fitness function, and the optimal threshold parameter set is determined after multiple iterations. The optimal threshold parameter set includes: main switch voltage, auxiliary switch voltage, and protection switch voltage. The optimized threshold parameters are input into the controller, and control commands are generated. The control commands are used to simulate the operation of the fuel cell stack at a rated power of 10kW. When the accumulated local potential is detected to exceed the safety threshold, the current distribution weight is automatically adjusted; the current density in the high-potential region is iterated multiple times from the initial value to gradually reduce it. Meanwhile, by redistributing the remaining current to the low-potential region and performing multiple iterations of suppression, the standard deviation of the overall potential distribution of the fuel cell stack is reduced, and the maximum potential difference is controlled within 0.01V, thereby achieving uniform potential distribution and effectively avoiding local overheating and performance degradation problems.

[0070] In one embodiment, the potential damage risk distribution of the electrolyte membrane is obtained from the simulation results of the suppressed potential distribution. Based on the risk distribution, the full-link data from signal acquisition to control execution is integrated to determine the link coordination parameters.

[0071] Based on the determined link coordination parameters, the updated instructions are input to the actual stack control system. The link coordination parameters are applied in real time during dynamic operation to obtain an optimized voltage management execution sequence, which is then used to generate control battery instructions.

[0072] Specifically, the present invention generates control battery commands through the following method: Based on the distribution of potential damage risk of the electrolyte membrane, the potential values ​​of each region of the electrolyte membrane are compared with the preset damage threshold. If the potential value exceeds the preset damage threshold, the area is marked as having a damage risk, and a damage risk distribution matrix is ​​obtained. Analyze the relationship between the risk areas of the damage risk distribution matrix and the location of the signal acquisition sensors, calculate the risk weight coefficients for each sensor, and determine the priority ranking of signal acquisition. Based on the priority of signal acquisition, real-time monitoring data of each sensor is obtained and multi-source sensor signals are integrated to form a full-link data flow vector; the coordination parameters between control execution nodes are calculated. If the rate of change of the data flow vector exceeds the preset change threshold, the coordination parameters are recalculated to obtain a dynamic coordination parameter set. Control command codes are generated based on a set of dynamic coordination parameters. Updated commands are input to each execution unit of the fuel cell stack control system via a communication interface, and system response confirmation signals are obtained. The potential change trend is predicted based on the system response confirmation signals. If the predicted trend shows an increased probability of pinhole damage, the voltage management strategy parameters are adjusted. The time-sequential voltage control command sequence is generated using the adjusted voltage management strategy parameters and sent to each control module of the fuel cell stack in real time to form an optimized voltage management execution sequence.

[0073] Extract potential gradient data for each region of the electrolyte membrane from the potential distribution simulation results; When the local potential difference in a certain area exceeds a preset threshold, the probability of pinhole damage in that area is calculated using a risk assessment matrix. The damage probability includes the assignment of potential gradients in high-risk, medium-risk, and low-risk areas.

[0074] Weighted fusion calculations are performed on real-time current density data, temperature distribution data, and humidity monitoring data to obtain comprehensive coordination parameters; When the comprehensive parameters exceed the threshold, control commands are generated, including voltage regulation amplitude, current distribution ratio adjustment and cooling system response time. When the fuel cell stack control system receives a control command with these parameters, it makes dynamic adjustments and monitors voltage fluctuation trends.

[0075] In this invention, by continuously updating coordination parameters at intervals, potential risk points are predicted in advance. When a potential risk occurs, the voltage distribution can be automatically adjusted to ensure that the voltage difference is controlled within a preset safe operating range. Based on this, an optimized voltage management execution sequence is formed. This optimized voltage management execution sequence is used to optimize the control of the battery, thereby preventing pinhole damage and improving the stability of system operation. The optimized voltage management execution sequence includes parameters such as timing control, amplitude limiting, and gradient constraints.

[0076] The present invention also provides a fuel cell system, which uses a control method to eliminate the high potential during fuel cell start-up and shutdown for system control, comprising: A fuel cell stack is used to generate electrical energy through an electrochemical reaction between hydrogen and oxygen in the air. The generated electrical energy powers the load module, i.e., it powers the user. The controller is used for real-time dynamic monitoring of the status of the fuel cell stack, recovery module, auxiliary power supply module, DC / DC module and user load, as well as for controlling the operation of the switching elements of the fuel cell stack and recovery module, auxiliary power supply module and DC / DC module; the recovery module is used to reduce the performance degradation of the fuel cell stack under startup and shutdown conditions, including load elements and switching elements. The auxiliary power supply module is used to store the electrical energy generated by the fuel cell stack to assist the fuel cell stack in providing power to the user load when the output is high. It is also used to provide initial energy for the entire system to start the system. The auxiliary power supply module can be either a lithium battery or a supercapacitor. DC / DC modules are used to convert the voltage of the fuel cell stack into a stable voltage that matches the user's load. One end of the user load is connected to the positive output of the DC / DC module, and the other end of the user load is connected to the negative output of the DC / DC module. The positive terminal of the fuel cell stack is connected to the positive input terminal of the DC / DC module, and the negative terminal of the fuel cell stack is connected to the negative input terminal of the DC / DC module. One end of the recovery module is connected to the positive terminal of the fuel cell stack, and the other end of the recovery module is connected to the negative terminal of the fuel cell stack. The auxiliary power supply module is connected in parallel with the user load.

[0077] In this invention, the fuel cell system is started up using a control method, and the start-up process includes the following steps: 1) The command to start the fuel cell system is issued.

[0078] 2) First, the thermal management system is turned on to maintain the stack temperature within a safe and efficient range.

[0079] 3) In the next step, the hydrogen system is started, and hydrogen is delivered to the anode of the fuel cell stack. When the preset start-up conditions are met, the switching element closes, the load element is connected to both ends of the fuel cell stack, and the voltage of a single cell in the fuel cell stack drops below 0.85V. The preset start-up conditions are that the voltage of a single cell in the fuel cell stack is greater than a preset value or the start-up time reaches a preset time.

[0080] 4) Then the air system is started, and air enters the cathode of the fuel cell stack and reacts with the hydrogen at the anode.

[0081] 5) In the next step, the DC / DC converter starts up, the switching elements are disconnected, the load elements are disconnected from both ends of the fuel cell stack, and the fuel cell stack charges the auxiliary power supply module and provides power to the load circuit.

[0082] 6) The preset value of 0.85V and the preset time of 2s are applied to the above steps.

[0083] The shutdown process for a fuel cell system, which combines control methods, includes the following steps: 1) The command to shut down the fuel cell system is issued.

[0084] 2) When a shutdown command to shut down the fuel cell system is issued, the following steps are included: DC / DC is turned off, switching elements are closed, load elements are connected to both ends of the fuel cell stack, and the air system is turned off in the next step.

[0085] 3) When the voltage of the fuel cell gradually decreases and the preset shutdown conditions are met, the switching element is disconnected and the connection between the load element and the two ends of the fuel cell is disconnected. The preset shutdown conditions are that the voltage of a single cell in the fuel cell is less than a preset value of two or the shutdown time reaches a preset time of two.

[0086] 4) Then, in the next step, the hydrogen system is shut down.

[0087] 5) Finally, when the stack temperature drops to a safe target temperature, the thermal management system shuts down, and the fuel cell system shutdown is complete.

[0088] 6) For the fuel cell stack, preset value two is 0.85V and preset time two is 15s, which are applied to the above steps.

[0089] This invention solves the problem of carbon corrosion of the catalyst layer caused by high potential during start-up and shutdown of fuel cell systems, as well as the problem of carbon corrosion and battery performance degradation caused by high cathode potential. Specifically, this invention achieves the goal of reducing high cathode potential by real-time monitoring of the fuel cell stack and dynamically adjusting the operation of the fuel cell based on the real-time monitoring results, thereby enabling the fuel cell stack to operate efficiently for a long time.

[0090] Furthermore, this invention collects physical data such as voltage, current, temperature, and humidity of the fuel cell stack; based on the collected physical data, it monitors the cathode potential of the fuel cell stack and determines whether it exceeds a preset value. If it exceeds the preset value, it triggers a recovery module to eliminate the high potential; by controlling the adjustable load element, it reduces the occurrence of cathode high potential and further suppresses carbon corrosion; furthermore, by reducing the occurrence of high potential, it reduces the degradation of fuel cell performance caused by carbon corrosion under high potential conditions, thus achieving the goal of extending the service life of the fuel cell.

[0091] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A control method for eliminating high potential during fuel cell start-up and shutdown, characterized in that, include: Obtain the stack operating status of the fuel cell system, and obtain cathode potential data of the stack under start-up and shutdown conditions based on the operating status; The system is determined to be in a high-potential state based on the cathode potential data. If it is in a high-potential state, the recovery module is triggered to perform a high-potential elimination operation.

2. The control method for eliminating high potential during fuel cell start-up and shutdown as described in claim 1, characterized in that, Collect voltage, current, temperature, and humidity data of the fuel cell stack to determine its operating conditions; based on the voltage data, determine whether the cathode potential exceeds the preset threshold. If the cathode potential exceeds a preset threshold, the fuel cell stack is determined to be in a high-potential state. Based on the cathode potential data, determine whether the high potential occurred during startup or shutdown. The recovery module eliminates high potentials during startup and shutdown conditions through load elements.

3. The control method for eliminating high potential during fuel cell start-up and shutdown as described in claim 1, characterized in that, When the fuel cell system is in startup mode, the following steps are taken: when a startup command is issued and the preset startup conditions are met, the switching element in the recovery module is closed, the load element is connected to both ends of the fuel cell stack, and the fuel cell stack voltage decreases; after the DC / DC module has started up, the switching element is opened; wherein, the preset startup conditions are that the voltage of a single cell in the fuel cell stack is greater than a preset value or the startup time reaches a preset time.

4. The control method for eliminating high potential during fuel cell start-up and shutdown as described in claim 3, characterized in that, When the fuel cell system is in shutdown condition, the following steps are taken: when a shutdown command is issued and the DC / DC module is turned off, the switching element in the recovery module is closed, the load element is connected to both ends of the fuel cell stack, and the fuel cell stack voltage decreases; when the shutdown preset conditions are met, the switching element is opened; wherein, the shutdown preset conditions are that the voltage of a single cell in the fuel cell stack is less than a preset value of two or the shutdown time reaches a preset time of two.

5. The control method for eliminating high potential during fuel cell start-up and shutdown as described in claim 3, characterized in that, When the start command for starting the fuel cell system is issued, the following steps are included: The thermal management system is activated to maintain the fuel cell stack temperature within a preset range; When the hydrogen system is started, hydrogen is delivered to the anode of the fuel cell stack. When the preset start-up conditions are met, the switching element closes, the load element is connected to both ends of the fuel cell stack, and the voltage of a single cell in the fuel cell stack drops below the preset voltage. The preset start-up conditions are that the voltage of a single cell in the fuel cell stack is greater than the preset value or the start-up time reaches the preset time. The air system is activated, and air enters the cathode of the fuel cell stack, reacting with the hydrogen at the anode to ensure that the cathode air pressure meets the operating conditions of the fuel cell stack.

6. The control method for eliminating high potential during fuel cell start-up and shutdown as described in claim 5, characterized in that, When the DC / DC module starts up, the switching elements are disconnected, the load elements are disconnected from both ends of the fuel cell stack, and the fuel cell stack charges the auxiliary power supply module and provides power to the load circuit.

7. The control method for eliminating high potential during fuel cell start-up and shutdown as described in claim 4, characterized in that, When a shutdown command to shut down the fuel cell system is issued, the following steps are included: the DC / DC module is shut down, the switching element is closed, the load element is connected to both ends of the stack, and the air system is shut down in the next step; When the voltage of the fuel cell stack drops to the preset shutdown condition, the switching element is disconnected and the connection between the load element and the two ends of the fuel cell stack is disconnected. The preset shutdown condition is that the voltage of a single cell in the fuel cell stack is less than a preset value of two or the shutdown time reaches a preset time of two. The hydrogen system shuts down; then, when the stack temperature drops to a safe target temperature, the thermal management system shuts down, and the fuel cell system shutdown is complete.

8. The control method for eliminating high potential during fuel cell start-up and shutdown as described in claim 5, characterized in that, The first preset value is 0.85V and the first preset time is 2 seconds; the second preset value is 0.85V and the second preset time is 15 seconds; the load element is an adjustable load, and further, the adjustable load is an adjustable transient discharge load.

9. The control method for eliminating high potential during fuel cell start-up and shutdown as described in claim 8, characterized in that, Microscopic distribution data of single cell voltage is collected from inside the fuel cell stack, and the collected voltage signals are processed to obtain voltage distribution data. The dynamic fluctuation trend is detected based on the obtained voltage distribution data; the voltage rise of each individual pool is quantified during load changes to determine the peak position and duration of the fluctuation trend. If the peak value of the determined fluctuation trend exceeds the preset threshold, the anomaly marking module is activated to evaluate the correlation between the marked single cell location and the voltage deviation of adjacent single cells, and obtain the deviation correlation index. Highly correlated regions are extracted from the obtained deviation correlation index. The triggering threshold of the switching element is adjusted according to the preset optimization model to match the response time requirement of the region, and the optimized threshold parameter set is determined. Based on the threshold parameter set, the stack operation scenario is simulated, and the local high potential accumulation in the simulation is iteratively suppressed to obtain the simulation result of the suppressed potential distribution. The potential damage risk distribution of the electrolyte membrane is obtained from the simulation results of the suppressed potential distribution. Based on the risk distribution, the full-link data from signal acquisition to control execution is integrated to determine the link coordination parameters. According to the determined link coordination parameters, the updated instructions are input to the actual stack control system. The link coordination parameters are applied in real time during dynamic operation to obtain the optimized voltage management execution sequence. The voltage management execution sequence is used to generate control battery instructions.

10. A fuel cell system, wherein a control method for eliminating high potential during fuel cell start-up and shutdown is applied for system control, comprising: The fuel cell stack is used to generate electrical energy through an electrochemical reaction between hydrogen and oxygen in the air, and the generated electrical energy powers the load module. That is, to supply power to users; The controller is used for dynamic monitoring of the real-time status of the fuel cell stack, recovery module, auxiliary power supply module, DC / DC module and user load, as well as for controlling the operation of the switching elements of the fuel cell stack, recovery module, auxiliary power supply module and DC / DC module; The recovery module is used to reduce the performance degradation of the fuel cell stack under startup and shutdown conditions, including load elements and switching elements; The auxiliary power supply module is used to store the electrical energy generated by the fuel cell stack to assist the fuel cell stack in providing power to the user load when the output is high. It is also used to provide initial energy for the entire system to start the system. The auxiliary power supply module can be either a lithium battery or a supercapacitor. DC / DC modules are used to convert the voltage of the fuel cell stack into a stable voltage that matches the user's load. One end of the user load is connected to the positive output of the DC / DC module, and the other end of the user load is connected to the negative output of the DC / DC module. The positive terminal of the fuel cell stack is connected to the positive input terminal of the DC / DC module, and the negative terminal of the fuel cell stack is connected to the negative input terminal of the DC / DC module. One end of the recovery module is connected to the positive terminal of the fuel cell stack, and the other end of the recovery module is connected to the negative terminal of the fuel cell stack. The auxiliary power supply module is connected in parallel with the user load.

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