A temperature-adaptive fuel cell end plate heating cold start method and system

Abstract

The application discloses a temperature self-adaptive fuel cell end plate heating cold start method and system, and relates to the technical field of fuel cell low-temperature cold start. The system comprises a temperature monitoring module, a high-frequency impedance detection module, a control module, a power distribution module and an end plate heating module which are sequentially connected in communication, and further comprises a cooling liquid circulating system and an ambient temperature detection device which are connected in communication with the control module. The method is realized based on the system and comprises the steps of core equipment calibration, basic parameter presetting, stack starting and data acquisition, icing critical moment determination and heating triggering, and temperature self-adaptive power regulation. Through the cooperative work of the numbering module, the application focuses on the single cell in the end plate area which is a weak link in cold start, realizes real-time determination of the icing state and dynamic adaptation of the heating power, greatly improves the reliability and economy of the fuel cell low-temperature cold start, and is suitable for fuel cell stacks of various models and power grades.

Description

Technical Field

[0001] This invention relates to the field of fuel cell cryogenic cold start technology, specifically to a temperature-adaptive fuel cell endplate heating cold start method and system. Background Technology

[0002] As a clean and efficient energy device, fuel cells have broad application prospects in new energy vehicles, distributed power generation, and other fields. However, in low-temperature environments, the endplate area of ​​the fuel cell stack, where individual cells are in direct contact with the external environment and lose heat quickly, becomes the coldest area in the stack and is highly susceptible to icing. Icing of individual cells in the endplate area leads to a sharp increase in stack impedance and significant voltage fluctuations, and in severe cases, even causes cold start failure, limiting the widespread application of fuel cells in low-temperature regions.

[0003] Existing fuel cell cold start technologies mostly employ a whole-stack heating approach, heating the entire stack. This approach suffers from poor heating targeting and high energy consumption. Furthermore, it lacks a precise monitoring and control mechanism specifically for individual cells in the endplate area, making it difficult to trigger heating in a timely manner during the initial icing stage. Additionally, the heating power adjustment cannot dynamically match the real-time heat deficit of individual cells at the endplate. Moreover, the poor coordination between modules in existing cold start systems, along with high data transmission and command execution delays, further impacts cold start performance. Therefore, developing a temperature-adaptive endplate heating cold start method and system with clearly defined module roles and high collaborative efficiency is of great significance for improving the low-temperature cold start performance of fuel cells. Summary of the Invention

[0004] The purpose of this invention is to provide a temperature-adaptive fuel cell endplate heating cold start method and system. Through modular collaborative operation, it can accurately determine the icing state of a single cell in the endplate area and dynamically adapt the heating power, thereby improving the reliability and economy of fuel cell low-temperature cold start.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] This invention aims to provide a temperature-adaptive endplate heating strategy for low-damage cold start, comprising the following steps:

[0007] S1 Core Equipment Calibration: A standard temperature source is used to calibrate each sensor in the temperature monitoring module, ensuring that the measurement error of the end-board single-cell temperature sensor is minimized. The sampling frequency is set to a reasonable level to adapt to the dynamic response during cold starts. The high-frequency impedance detection module is calibrated to ensure it can detect minute impedance changes, with the detection frequency consistent with the temperature monitoring module. The power distribution module is calibrated to ensure that the heating power ratio adjustment error is minimized and the response delay is extremely low. The coolant circulation system is calibrated to determine the target coolant flow rate that balances heat dissipation and insulation requirements. The control module and ambient temperature detection equipment are calibrated to ensure stable communication and accurate measurements.

[0008] S2 basic parameter preset: The target coolant flow rate, optimal load rate, and high-frequency impedance threshold corresponding to a specific low-temperature environment are preset by the control module. An associated database of ambient temperature, heat gap, and heating power ratio is established. The threshold for successful cold start is preset (the temperature of a single cell at the end plate is stable above the freezing critical temperature for a certain period of time, the voltage is within a reasonable range, and the impedance is within the normal range).

[0009] S3 stack startup and data acquisition: The control module controls the stack to be linearly loaded at the optimal loading rate, and the current density is gradually increased from 0 to the set termination level. The temperature monitoring module collects the temperature data of the single cell at the end plate in real time (the initial temperature is the typical low temperature). The high-frequency impedance detection module collects the impedance data synchronously (the initial impedance is the normal initial level). The control module calculates the heat gap (the initial is a large level) and tracks the temperature and impedance change trends in real time.

[0010] S4 Icing Critical Moment Judgment and Heating Trigger: When the impedance of a single cell at the end plate is detected to rise to the preset high-frequency impedance threshold, the control module determines that it is the icing critical moment and immediately sends a heating command to the power distribution module. The power distribution module calls the heating power ratio (medium to high level) corresponding to the ambient temperature and heat gap, and distributes the stack output power to the end plate heating module according to this ratio. The cathode end plate heating element and the anode end plate heating element are activated to heat evenly.

[0011] S5 Temperature Adaptive Power Adjustment: After heating starts, the control module continuously receives data. When it detects that the temperature rise rate of a single cell at the end board increases significantly, the heat gap shrinks to a low level, and the impedance tends to stabilize (fluctuation range is very small), the heating power ratio is gradually reduced (each reduction is a small amount). When the temperature of all single cells at the end board rises above the freezing critical temperature and the temperature of other single cells reaches the standard simultaneously, the heating power ratio is reduced to a low maintenance level. During this period, voltage changes are monitored simultaneously. If there are no abnormal fluctuations, the temperature of the single cells at the end board will stabilize above the freezing critical temperature for the set duration, the impedance will stabilize near the normal range, and the voltage will stabilize near the reasonable range. The cold start is then determined to be successful.

[0012] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0013] 1. Modular and collaborative high efficiency, high data reliability: By clearly defining the module number and function, the temperature monitoring, impedance detection, control, power distribution and other modules can work together. The standardized calibration process of each module ensures the accuracy of measurement data and control commands, providing reliable support for icing state determination and heating power adjustment.

[0014] 2. Targeted heating and high precision in preventing icing: This invention directly monitors the status of single cells in the end-plate area through the end-plate single-cell temperature sensor of the temperature monitoring module, and combines it with the precise heating of the cathode and anode end-plate heating elements of the end-plate heating module to focus on the weak links in cold start, suppressing icing of single cells in the end-plate area from the source, and significantly reducing the cold start failure rate (the cold start success rate is increased to over 98% at a low temperature of -30℃).

[0015] 3. Energy consumption optimization and improved economy: The temperature-adaptive power adjustment mechanism is adopted to dynamically adjust the heating power based on the real-time status of the single battery at the end board, avoiding the waste of energy consumption in overall heating. The preset optimal load rate and heating power ratio database further balances the start-up efficiency and energy consumption, reducing energy consumption by more than 30% during the cold start process.

[0016] 4. High adaptability and wide applicability: The calibration parameters and preset parameters of each module of the system can be flexibly adjusted according to the stack model, power level and target cold start temperature range. It is suitable for various low temperature conditions (-40℃ to 0℃) and fuel cell stacks of different power levels (50-200kW), and has a wide range of application prospects. Attached Figure Description

[0017] Figure 1 This is a diagram showing the composition of the temperature-adaptive fuel cell endplate heating cold start system of the present invention.

[0018] Figure 2 This is a flowchart of the temperature-adaptive fuel cell endplate heating cold start method of the present invention. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figure 1 and Figure 2As shown, this embodiment takes a commercial proton exchange membrane fuel cell stack as the research object and elaborates on the application process of a temperature-adaptive fuel cell endplate targeted heating cold start strategy. All parameters involved are illustrative examples and can be flexibly adjusted according to the stack model, power level and application scenario in actual applications.

[0021] A temperature-adaptive fuel cell endplate heating cold start method includes the following steps:

[0022] The S1 core equipment calibration step aims to ensure the measurement accuracy and operational stability of each module, providing reliable data support for subsequent cold start control. Specifically, it includes:

[0023] S1.1 Temperature Monitoring Module 1 Calibration: A standard temperature source is used to perform full-range calibration on the end-board single-cell temperature sensor 11 and the end-board surface temperature sensor 12, covering the range from extreme low temperature to normal temperature, to ensure that the measurement error of each sensor is at a minimum level. The data sampling frequency of the data transmission unit 14 is set to match the dynamic response requirements of rapid temperature changes during cold start. The signal transmission line of the temperature monitoring module 1 is subjected to anti-interference test, and shielded wires are used to optimize the line layout to avoid signal attenuation or distortion in low temperature environment. At the same time, the coolant temperature sensor 13 is calibrated using a standard temperature source to ensure that it can accurately reflect the heat exchange status of the coolant and provide reference data for matching the end-board heating strategy.

[0024] S1.2 High-frequency impedance detection module 2 calibration: High-precision standard resistors are used to perform impedance calibration on impedance detection unit 21, covering the range of impedance changes that may occur in a single cell at the end plate during cold start, verifying the measurement accuracy of the detection module. By using a signal generator to simulate the impedance signals corresponding to different impedance correlation icing states, based on the characteristic that icing increases the mass transfer resistance and charge transfer resistance of a single cell, thus increasing the impedance, the ability of signal processing unit 22 to identify small impedance changes is tested to ensure that it can stably capture the characteristic impedance signal of the single cell at the end plate in the initial stage of icing. The detection frequency of high-frequency impedance detection module 2 is calibrated to be consistent with the sampling frequency of temperature monitoring module 1, so as to realize the synchronous acquisition of temperature data and impedance data.

[0025] S1.3 Power Distribution Module 4 Calibration: Connect a programmable electronic load to simulate the output power of the fuel cell stack. During the cold start process, within the possible output power level range of the fuel cell stack, calibrate the output accuracy of the power distribution module 4, test the stability of the module during dynamic power adjustment, ensure that the adjustment error of the end plate heating power ratio is at a minimum level, detect the response delay of the module to the control command of the control module 3, ensure that the requirements for rapid triggering of end plate heating are met, and ensure that the heating power can match the heat gap of the single cell at the end plate in a timely manner.

[0026] S1.4 Coolant Circulation System 6 Calibration: Conduct cold start comparative tests under different coolant flow rates, set a reasonable test flow range, and record the temperature distribution of individual cells at the stack endplate, the icing rate characterized by the high-frequency impedance increase rate, and the stack start-up status at each flow rate. When the flow rate increases to a certain value, the temperature difference between the endplate and the individual cells in the stack is no longer significant. This is used to initially determine the effective flow range. Based on the principle of heat transfer, combined with parameters such as the stack rated power, coolant specific heat capacity, and allowable temperature difference between the stack inlet and outlet, the minimum coolant flow rate required for stack heat dissipation is calculated. Considering the characteristic that the stack output power is lower than the peak power during the cold start stage, the minimum coolant flow rate is adjusted. The minimum flow threshold under cold start conditions is obtained. A standard flow meter and a built-in flow meter 62 are connected in series to the coolant circulation pipeline 64. Within the initially determined flow range, target flow rates are set at reasonable intervals. After each target flow rate has been running stably for a period of time, the readings of the standard flow meter and the built-in flow meter 62 are recorded synchronously. The indication error of the built-in flow meter 62 is calculated. If the error exceeds the allowable range, the flow control parameters are adjusted through the control module 3 until the error meets the requirements. Finally, the target coolant flow rate that balances temperature uniformity and heat retention is selected. This flow rate can meet the heat dissipation requirements of the fuel cell stack and reduce heat loss during cold start, thus delaying the freezing of individual cells at the end plate.

[0027] S1.5 Control Module 3 Calibration: Functional verification of the built-in cold start control algorithm is performed. Simulated endplate area temperature data and high-frequency impedance data are input to control module 3 through a signal generator to test the accuracy of the algorithm in calculating the heat gap of a single cell at the endplate. The rationality of the algorithm in determining the critical freezing moment and the allocation of heating power is verified to ensure that the judgment error is within the allowable range. Communication stability test is carried out between control module 3 and temperature monitoring module 1, high-frequency impedance detection module 2, and power allocation module 4. The system is run continuously for a period of time to ensure that there is no packet loss or delay in command transmission and data reception. The signal acquisition interface of control module 3 is calibrated to ensure that the data acquisition accuracy matches the output accuracy of each sensor and detection unit.

[0028] S1.6 Ambient Temperature Detection Equipment 7 Calibration: A professional-grade standard thermometer is used to calibrate the ambient temperature detection equipment 7. The calibration range covers the target cold start temperature range. Data is collected and compared multiple times at each calibration temperature point to ensure that the ambient temperature measurement error is within the allowable range and meets the accuracy requirements of parameter calling, providing an accurate basis for the corresponding operating parameters of the subsequent loading end plate heating.

[0029] The S2 basic parameter preset is based on multiple sets of low-temperature cold start test data from previous tests. The core parameters are preset through control module 3 to ensure that all modules work in a coordinated and orderly manner during the cold start process. Specifically, this includes:

[0030] S2.1 Set target coolant flow rate: Based on the stack model and heat dissipation requirements, combined with calculations based on heat transfer principles and cold start test results at different flow rates, set the target coolant flow rate to ensure both heat dissipation and heat retention, and to slow down the icing rate of individual cells at the end plate.

[0031] S2.2 Setting the optimal load rate: Through multiple sets of low-temperature cold start comparative tests, different load rates were set, and the temperature rise rate, icing development process, and voltage stability of the single cell at the end plate were monitored. The test found that when the load rate was too low, the temperature rise of the single cell at the end plate was slow, and the long-term low temperature environment led to the aging of the proton exchange membrane. When the load rate was too high, the electrochemical reaction rate increased sharply, the product water generation rate exceeded the heat dissipation rate, the icing intensified, and the voltage downsampling was too large. Based on the fitting analysis of the experimental data, the optimal load rate that is suitable for cold start aging, suppresses icing development, and the voltage fluctuation is within the safe range was selected.

[0032] S2.3 Apply high-frequency impedance threshold: Apply high-frequency impedance thresholds corresponding to different ambient temperatures. These thresholds are calibrated through multiple sets of low-temperature tests, and are associated with the initial stage of single-cell icing at the end plate, thus clarifying the criteria for determining the critical moment of single-cell icing at the end plate.

[0033] S2.4 Establish a database linking heating power ratio: Establish a database linking ambient temperature, single-cell heat gap at endplate, and heating power ratio, covering the target cold start temperature range. The heating power is allocated according to a certain proportion of the stack output power to ensure energy consumption is reduced while ensuring successful cold start.

[0034] S2.5 Preset Cold Start Success Threshold: The preset cold start success threshold includes the following key points: the temperature of a single cell at the end board remains stable above the freezing critical temperature for a period of time, the voltage remains stable within a reasonable range, the impedance remains stable within the normal range, and there are no abnormal voltage fluctuations.

[0035] S3 Stack Start-up and Data Acquisition S3.1 Stack Start-up: Control module 3 sends a start-up command to the stack and performs linear loading according to the preset optimal loading rate. The current density gradually increases from 0 to the termination current density. The duration of the loading process is calculated based on the loading rate and the termination current density.

[0036] S3.2 Temperature Data Acquisition: During the load test, the end plate single cell temperature sensor 11, end plate surface temperature sensor 12, and coolant temperature sensor 13 of the temperature monitoring module 1 collect data in real time at the set sampling frequency and transmit it to the control module 3 through the data transmission unit 14. The control module 3 focuses on recording the temperature change trend of the single cell at the end plate.

[0037] S3.3 Heat gap calculation: The control module 3 calculates the difference between the single cell temperature at the end plate and the freezing critical temperature, i.e., the heat gap, based on the temperature data collected by the end plate single cell temperature sensor 11, and tracks the temperature dynamics of the "low temperature bottleneck" at the end plate.

[0038] S3.4 Impedance Data Acquisition: The impedance detection unit 21 of the high-frequency impedance detection module 2 synchronously acquires the impedance data of the single battery at the end plate at a set frequency. After being processed by the signal processing unit 22, the data is transmitted to the control module 3 to capture the slight fluctuations in the impedance value.

[0039] S3.5 Icing State Determination: Based on the previously calibrated impedance and icing state correlation, control module 3 determines the icing development state of a single cell at the end plate in real time, providing data support for determining the critical icing moment.

[0040] S3.6 Power Monitoring: Control module 3 receives and processes all collected data in real time, dynamically updates the calculation results of the single cell thermal deficit at the end board, and synchronously monitors the changes in the stack output power.

[0041] S4 Icing Critical Moment Judgment and Heating Trigger S4.1 Impedance Comparison: Control module 3 compares the real-time impedance of a single cell at the end plate transmitted by high-frequency impedance detection module 2 with the preset high-frequency impedance threshold, focusing on tracking the impedance change trend.

[0042] S4.2 Critical Moment Determination: When the impedance of a single cell at the end plate is detected to reach a set threshold, the control module 3 determines the critical moment of icing (corresponding to the initial stage of icing) based on the correlation between impedance and icing state.

[0043] S4.3 Heating command transmission: Control module 3 quickly sends a heating start command to power distribution module 4, with a response delay of extremely low level.

[0044] S4.4 Power Allocation: Based on the current ambient temperature, the ambient temperature detection device 7 collects data, the control module 3 calculates the real-time heat gap of the single cell at the end plate and the output power of the fuel cell stack, the power allocation module 4 retrieves the corresponding heating power ratio from the associated database and allocates the output power of the fuel cell stack to the end plate heating module 5 according to the ratio, while ensuring the normal power supply needs of auxiliary components such as the circulating water pump 61 and the air compressor.

[0045] S4.5 Heating Start: After receiving the instruction, the end plate heating module 5 immediately starts the cathode end plate heating element 51 and the anode end plate heating element 52, and the heating power is evenly distributed to the two end plates to ensure that the single cell at the end plate heats up synchronously and quickly makes up for the heat gap.

[0046] S5 Temperature Adaptive Power Regulation S5.1 Continuous Data Monitoring: After heating starts, the control module 3 continuously receives the single-cell temperature data at the end board transmitted by the temperature monitoring module 1 and the impedance data transmitted by the high-frequency impedance detection module 2, and the sampling frequency remains at an appropriate level.

[0047] S5.2 Status Update: Real-time updates of the calculation results of the single-cell thermal gap at the endplate and the determination results of the icing status.

[0048] S5.3 Power Ratio Reduction: When the temperature rise rate of a single cell at the end plate is significantly accelerated, the heat gap gradually shrinks to below the preset threshold, and the impedance value tends to stabilize with a very small fluctuation range, indicating that the development of icing is suppressed, the control module 3 gradually reduces the heating power ratio of the end plate through the power distribution module 4, reducing it by a small amount each time to avoid energy waste and local overheating caused by overheating.

[0049] S5.4 Stable Phase Adjustment: When the temperature of all single cells at the end plate rises above the freezing critical temperature and the temperature of other single cells reaches the standard simultaneously, the control module 3 determines that the cold start has entered the stable phase, further reducing the heating power ratio to a lower maintenance level to ensure temperature stability and prevent secondary freezing.

[0050] S5.5 Abnormal Fine-tuning: During this process, the control module 3 synchronously monitors the voltage change of the single cell at the end plate (acquired through the stack voltage monitoring unit) to ensure that the electrochemical reaction proceeds normally and there is no abnormal voltage fluctuation. If the temperature of a single cell rises slowly or the impedance is abnormal (deviating significantly from the normal range), the heating power of the corresponding end plate heating element is fine-tuned in a timely manner through the power distribution module 4 (the fine-tuning range is small) to ensure the uniformity of the temperature distribution of the single cell at the end plate (the temperature difference is within a very small range).

[0051] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0052] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment have been appropriately combined to form other embodiments that are easy for those skilled in the art to understand.

Claims

1. A temperature-adaptive fuel cell endplate heating cold start system, characterized in that, include: Temperature monitoring module (1), high frequency impedance detection module (2), control module (3), power distribution module (4), end plate heating module (5), coolant circulation system (6) and ambient temperature detection equipment (7); The temperature monitoring module (1) is used to collect relevant temperature data of the fuel cell endplate, and the high-frequency impedance detection module (2) is used to collect impedance-related signals of a single cell at the fuel cell endplate. The signal output terminals of both modules are connected to the signal input terminal of the control module (3) for transmitting the collected temperature data and impedance-related signals to the control module (3). The control output terminal of the control module (3) is connected to the signal input terminal of the power distribution module (4) for sending power distribution control commands to the power distribution module (4). The power output terminal of the power distribution module (4) is connected to the power input terminal of the endplate heating module (5). The connection is used to allocate the appropriate power to the end plate heating module (5) according to the instructions of the control module (3). The coolant circulation system (6) is used to realize the circulation regulation of the fuel cell stack coolant. The ambient temperature detection device (7) is used to collect the temperature data of the environment where the fuel cell is located. The signal output terminals of both are connected to the signal input terminal of the control module (3) to transmit coolant circulation related data and ambient temperature data to the control module (3). The control input terminal of the coolant circulation system (6) is connected to the control output terminal of the control module (3) to receive the regulation instructions of the control module (3) to perform circulation state adjustment. The temperature monitoring module (1) includes an end plate single cell temperature sensor (11) for collecting the temperature of a single cell in the end plate area, an end plate surface temperature sensor (12) for collecting the temperature of the end plate, a coolant temperature sensor (13) for collecting the temperature of the coolant, and a data transmission unit (14). The data transmission unit (14) is used to transmit various temperature data collected by the end plate single cell temperature sensor (11), the end plate surface temperature sensor (12) and the coolant temperature sensor (13) to the control module (3). The high-frequency impedance detection module (2) includes an impedance detection unit (21) and a signal processing unit (22). The impedance detection unit (21) is used to collect the impedance signal of a single cell at the end plate. The signal processing unit (22) is used to filter and amplify the collected impedance signal and transmit the processed impedance data to the control module (3). The end plate heating module (5) includes a cathode end plate heating element (51) for heating the cathode end plate and an anode end plate heating element (52) for heating the anode end plate. Both the cathode end plate heating element (51) and the anode end plate heating element (52) are electrically connected to the power output terminal of the power distribution module (4), and their heating power can be adjusted independently to achieve differentiated heating control of the cathode and anode end plates. The coolant circulation system (6) includes a circulating water pump (61), a built-in flow meter (62) for detecting coolant flow, a coolant storage tank (63), and a pipeline (64) for constructing a circulation path. The circulating water pump (61) is used to drive the coolant to circulate, and the built-in flow meter (62) is used to collect coolant flow data. The control input terminals of both are connected to the control output terminal of the control module (3) to receive instructions from the control module (3) to adjust the pump operation status and provide feedback flow data.

2. A temperature-adaptive fuel cell endplate heating cold start method based on the system of claim 1, characterized in that, Includes the following steps: S1. Core equipment calibration: The temperature monitoring module (1), high frequency impedance detection module (2), power distribution module (4), coolant circulation system (6), control module (3), and ambient temperature detection device (7) are calibrated in sequence. S2, Basic parameter preset: Based on multiple sets of low temperature cold start test data, the core parameters are preset through the control module (3); S3, Stack Start-up and Data Acquisition: The control module (3) controls the stack start-up and simultaneously collects relevant data of the single cell at the end plate through the temperature monitoring module (1) and the high-frequency impedance detection module (2); S4. Determination of the critical moment of freezing and triggering of heating: The control module (3) determines the critical moment of freezing based on the collected impedance data and triggers the end plate heating module (5) to work. S5, Temperature-adaptive power adjustment: The control module (3) dynamically adjusts the heating power of the end plate heating module (5) based on the real-time collected data; The calibration of the temperature monitoring module (1) in step S1 includes: S1.

1. Use a standard temperature source to perform full-range calibration on the end plate single cell temperature sensor (11) and end plate surface temperature sensor (12), covering the range from extreme low temperature to normal temperature, to ensure that the measurement error is within the allowable range. S1.2 Set the data sampling frequency of the data transmission unit (14) to match the dynamic response requirements of cold start; S1.3 Perform anti-interference test on the signal transmission line of the temperature monitoring module (1); S1.4 The coolant temperature sensor (13) is calibrated using a standard temperature source to ensure accurate feedback of the coolant heat exchange status; The calibration of the high-frequency impedance detection module (2) in step S1 includes: S1.

5. Use a high-precision standard resistor to perform impedance calibration on the impedance detection unit (21) to cover the impedance change range of the single cell at the end plate during the cold start process. S1.6 By simulating the impedance signals corresponding to different impedance correlation icing states, the signal processing unit (22) is tested for its ability to identify minute impedance changes. S1.

7. Calibrate the detection frequency of the high-frequency impedance detection module (2) to make it consistent with the sampling frequency of the temperature monitoring module (1); The calibration of the coolant circulation system (6) in step S1 includes: S1.8 Conduct cold start comparison tests under different coolant flow rates, record the temperature distribution of a single cell at the end plate of the fuel cell stack under each flow rate, the freezing rate characterized by the high-frequency impedance increase rate, and the start-up state, and preliminarily determine the effective range of the flow rate; S1.9 Calculate the minimum coolant flow rate required for heat dissipation of the fuel cell stack based on the principle of heat transfer, and make corrections based on the output power characteristics of the fuel cell stack during the cold start phase; S1.

10. The actual flow deviation corresponding to different set flow rates is calibrated by comparing the standard flow meter and the built-in flow meter (62) in series. S1.11, Select the target coolant flow rate that balances temperature uniformity and heat retention; The core parameters in step S2 include: target coolant flow rate, optimal load rate, high-frequency impedance threshold corresponding to different ambient temperatures, ambient temperature-heat gap-heating power ratio correlation database, and cold start success determination threshold. The optimal load rate is determined through multiple sets of low-temperature cold start comparison tests, specifically by monitoring the temperature rise rate of a single cell at the end plate, the icing development process, and the core indicators of voltage stability, and is obtained by fitting and analyzing the test data. The high-frequency impedance threshold is calibrated through multiple sets of low-temperature tests and is associated with the initial stage of icing of a single cell at the end plate. Step S4 specifically includes: S4.1, Control module (3) compares the real-time impedance of a single cell at the end plate of the high-frequency impedance detection module (2) with the preset high-frequency impedance threshold in real time. S4.2 When the real-time impedance reaches the preset threshold, the control module (3) determines it to be the critical moment of freezing; S4.3, The control module (3) sends a heating start command to the power distribution module (4); S4.4 The power distribution module (4) calls the heating power ratio in the associated database according to the current ambient temperature, the real-time heat gap of the single cell at the end plate calculated by the control module (3) and the output power of the stack, and distributes the output power of the stack to the cathode end plate heating element (51) and anode end plate heating element (52) of the end plate heating module (5) in proportion. S4.5, the heating element (51) of the negative end plate and the heating element (52) of the positive end plate are started to realize the heating of the end plate area; Step S5 specifically includes: S5.1 After heating is started, the control module (3) continuously receives temperature data transmitted by the temperature monitoring module (1) and impedance data transmitted by the high-frequency impedance detection module (2); S5.2 Real-time update of the calculation results of the single cell thermal gap at the end plate and the determination results of the icing state; S5.3 When the temperature rise rate of a single cell at the end plate is accelerated, the heat gap is reduced to below the preset threshold and the impedance tends to stabilize, the control module (3) gradually reduces the heating power ratio of the cathode end plate heating element (51) and the anode end plate heating element (52) through the power distribution module (4). S5.4 When the temperature of a single cell at the end plate rises above the freezing critical temperature and the temperature of other single cells reaches the standard simultaneously, the control module (3) reduces the heating power ratio to a maintenance level. S5.5 If it is detected that the temperature of a single cell at the end plate rises slowly or the impedance is abnormal, the control module (3) fine-tunes the heating power of the corresponding end plate heating element through the power distribution module (4).

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