A method and device for cold starting a stack based on single stack consistency

Abstract

The application discloses a kind of based on single stack consistency electric pile cold start method and device, method is responded to cold start signal, according to preset voltage range voltage is delivered to electric pile, and the operating feedback current of electric pile is detected;If operating feedback current is greater than first preset current threshold, then according to first preset hydrogen air metering ratio, the air inlet flow of electric pile is adjusted, until less than first preset current threshold;According to preset interval time, operating feedback current is collected;According to the comparison result of operating feedback current and second preset current threshold and second preset hydrogen air metering ratio, the air inlet flow of electric pile is adjusted, until electric pile reaches start temperature, to quickly and simply carry out the electric pile cold start control of solid oxide fuel cell.

Description

Technical Field

[0001] This invention relates to the field of fuel cell stack cold start technology, and in particular to a fuel cell stack cold start method and apparatus based on single-stack consistency. Background Technology

[0002] Solid oxide fuel cells (SOFCs) are power generation devices with advantages such as high efficiency, energy saving, environmental friendliness, and wide fuel applicability. Under normal circumstances, SOFCs operate at temperatures between 600-800℃. During startup, they are first heated to their startup temperature before generating electricity. Therefore, how to rapidly and safely heat an SOFC to its startup temperature is one of the main challenges currently hindering its development.

[0003] Existing solutions primarily focus on improving and optimizing the battery's heat transfer mechanism and the causes of thermal stress during startup. During battery fabrication, improvements are made to catalysts to mitigate deformation and stress generated during sintering. During preheating and startup, the temperature gradient distribution is controlled by improving the thermal expansion coefficients of materials used in various battery components.

[0004] Since existing solutions mainly focus on improving materials and catalysts in the battery manufacturing process, technological breakthroughs are difficult, making it hard to quickly and easily control the cold start of solid oxide fuel cell stacks. Summary of the Invention

[0005] This invention provides a method and apparatus for cold start of a fuel cell stack based on single-stack consistency, which solves the technical problem that existing solutions mainly focus on improving materials and catalysts in the battery preparation process, making it difficult to achieve rapid and convenient control of cold start of solid oxide fuel cell stacks.

[0006] This invention provides a cold start method for electric stacks based on single-stack consistency, comprising:

[0007] In response to a cold start signal, the system supplies voltage to the fuel cell stack according to a preset voltage range and detects the operating feedback current of the fuel cell stack.

[0008] If the operating feedback current is greater than the first preset current threshold, the air inlet flow rate of the fuel cell stack is adjusted according to the first preset hydrogen-air metering ratio until it is less than the first preset current threshold.

[0009] The operating feedback current is collected at preset intervals.

[0010] Based on the comparison result between the operating feedback current and the second preset current threshold and the second preset hydrogen-air metering ratio, the air inlet flow rate of the fuel cell stack is adjusted until the fuel cell stack reaches the start-up temperature.

[0011] Optionally, the method further includes:

[0012] When the fuel cell stack is shut down, the fuel cell stack is deloaded according to a preset deload slope until the temperature of the fuel cell stack drops to a first preset temperature;

[0013] Open the cathode tail valve of the fuel cell stack and adjust the three-way valve to humidify the air intake of the cathode and anode of the fuel cell stack.

[0014] Turn on the tail heater at the cathode exhaust end of the fuel cell stack;

[0015] Hydrogen gas with a first relative humidity is introduced into the anode of the fuel cell at a first preset flow rate, and air with a second relative humidity is introduced into the cathode of the fuel cell at a second preset flow rate and maintained for a preset time.

[0016] Optionally, the step of adjusting the air inlet flow rate of the fuel cell stack according to the first preset hydrogen-air metering ratio if the operating feedback current is greater than the first preset current threshold, until it is less than the first preset current threshold, includes:

[0017] If the operating feedback current is greater than the first preset current threshold, the first initial flow rate of the fuel cell stack is calculated according to the preset control formula.

[0018] The mixed gas is input into the fuel cell stack according to the first initial flow rate and the first preset hydrogen-air metering ratio until the operating feedback current is less than the first preset current threshold.

[0019] The control formula is:

[0020]

[0021] in, Let k be the initial flow rate at time k. This is the proportional gain coefficient. This is the integral gain coefficient. The differential gain coefficient, This is the cumulative sum of all deviation values ​​from time 0 to time k. Current deviation value Deviation value from the previous time difference.

[0022] Optionally, adjusting the air inlet flow rate of the fuel cell stack according to the comparison result of the operating feedback current and the second preset current threshold and the second preset hydrogen-air metering ratio until the fuel cell stack reaches the start-up temperature includes:

[0023] Compare the operating feedback current with the second preset current threshold;

[0024] If the operating feedback current is greater than the second preset current threshold, then the second initial flow rate of the fuel cell stack is calculated according to the preset control formula;

[0025] Input the mixed gas according to the second initial flow rate and the second preset hydrogen-air metering ratio, and detect the current hydrogen column flow rate;

[0026] The bypass flow rate is calculated as the target value using the current hydrogen column flow rate combined with the split ratio formula.

[0027] Adjust the air inlet flow rate of the fuel cell stack according to the target value until the fuel cell stack reaches the start-up temperature.

[0028] Optionally, the method further includes:

[0029] The real-time voltage and real-time current of the fuel cell stack are detected;

[0030] If the real-time voltage or the real-time current does not reach the rated value, then proceed to the step of collecting the operating feedback current at preset intervals.

[0031] This invention provides a cold start device for fuel cell stacks based on single-stack consistency, comprising:

[0032] The real-time feedback current detection module is used to respond to the cold start signal, deliver voltage to the fuel cell stack according to a preset voltage range, and detect the operating feedback current of the fuel cell stack.

[0033] The first flow rate adjustment module is used to adjust the air inlet flow rate of the fuel cell stack according to the first preset hydrogen-air metering ratio if the operating feedback current is greater than the first preset current threshold, until it is less than the first preset current threshold.

[0034] The current re-acquisition module is used to acquire the operating feedback current at preset intervals.

[0035] The second flow adjustment module is used to adjust the air inlet flow of the fuel cell stack according to the comparison result of the operating feedback current and the second preset current threshold and the second preset hydrogen-air metering ratio, until the fuel cell stack reaches the start-up temperature.

[0036] Optionally, the device further includes:

[0037] The unloading module is used to unload the fuel cell stack according to a preset unloading slope when the stack is shut down, until the temperature of the stack drops to a first preset temperature.

[0038] The first opening module is used to open the cathode tail valve of the fuel cell stack and adjust the three-way valve to make the cathode and anode of the fuel cell stack humidified.

[0039] The second activation module is used to activate the tail heater at the cathode exhaust end of the fuel cell stack.

[0040] A gas inlet module is used to introduce hydrogen gas with a first relative humidity into the anode of the fuel cell stack at a first preset flow rate, and to introduce air with a second relative humidity into the cathode of the fuel cell stack at a second preset flow rate and maintain the flow for a preset time.

[0041] Optionally, the first flow adjustment module is specifically used for:

[0042] If the operating feedback current is greater than the first preset current threshold, the first initial flow rate of the fuel cell stack is calculated according to the preset control formula.

[0043] The mixed gas is input into the fuel cell stack according to the first initial flow rate and the first preset hydrogen-air metering ratio until the operating feedback current is less than the first preset current threshold.

[0044] The control formula is:

[0045]

[0046] in, Let k be the initial flow rate at time k. This is the proportional gain coefficient. This is the integral gain coefficient. The differential gain coefficient, This is the cumulative sum of all deviation values ​​from time 0 to time k. Current deviation value Deviation value from the previous time difference.

[0047] Optionally, the second flow adjustment module is specifically used for:

[0048] Compare the operating feedback current with the second preset current threshold;

[0049] If the operating feedback current is greater than the second preset current threshold, then the second initial flow rate of the fuel cell stack is calculated according to the preset control formula;

[0050] Input the mixed gas according to the second initial flow rate and the second preset hydrogen-air metering ratio, and detect the current hydrogen column flow rate;

[0051] The bypass flow rate is calculated as the target value using the current hydrogen column flow rate combined with the split ratio formula.

[0052] Adjust the air inlet flow rate of the fuel cell stack according to the target value until the fuel cell stack reaches the start-up temperature.

[0053] Optionally, the device further includes:

[0054] A real-time detection module is used to detect the real-time voltage and real-time current of the fuel cell stack.

[0055] The cyclic adjustment module is used to jump to the step of collecting the operating feedback current at preset intervals if the real-time voltage or the real-time current does not reach the rated value.

[0056] As can be seen from the above technical solutions, the present invention has the following advantages:

[0057] This invention responds to a cold start signal, delivers voltage to the fuel cell stack according to a preset voltage range, and detects the operating feedback current of the fuel cell stack. If the operating feedback current is greater than a first preset current threshold, the air inlet flow rate of the fuel cell stack is adjusted according to a first preset hydrogen-air metering ratio until it is less than the first preset current threshold. The operating feedback current is collected at preset intervals. Based on the comparison result between the operating feedback current and a second preset current threshold and the second preset hydrogen-air metering ratio, the air inlet flow rate of the fuel cell stack is adjusted until the fuel cell stack reaches the start-up temperature, thereby enabling rapid and convenient cold start control of the solid oxide fuel cell stack. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 A flowchart illustrating the steps of a cold start method for an electric stack based on single-stack consistency, provided in an embodiment of the present invention;

[0060] Figure 2 This is a schematic diagram of an AC impedance monitoring structure according to an embodiment of the present invention;

[0061] Figure 3 This is a flowchart of a cold start control method according to an embodiment of the present invention;

[0062] Figure 4 This is a structural block diagram of a cold start device for an electric stack based on single-stack consistency, provided as an embodiment of the present invention. Detailed Implementation

[0063] This invention provides a method and apparatus for cold start of a fuel cell stack based on single-stack consistency, which addresses the technical problem that existing solutions mainly focus on improving materials and catalysts during the battery manufacturing process, making it difficult to achieve rapid and convenient control of cold start of solid oxide fuel cell stacks.

[0064] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0065] Please see Figure 1 , Figure 1 A flowchart illustrating the steps of a cold start method for an electric stack based on single-stack consistency, provided in an embodiment of the present invention.

[0066] This invention provides a cold start method for electric stacks based on single-stack consistency, comprising:

[0067] Step 101: In response to the cold start signal, supply voltage to the fuel cell stack according to the preset voltage range, and detect the operating feedback current of the fuel cell stack;

[0068] Single-cell consistency typically refers to the stability and consistency of parameters such as output voltage and current of each individual cell in the fuel cell stack at rated power. This includes key performance indicators such as the standard deviation of individual cell voltage, the overall power density of the stack, and its hermeticity.

[0069] A cold start signal refers to the start signal used to activate the flow control equipment associated with the fuel cell stack, in order to heat the stack from room temperature or low temperature to its operating temperature. This flow control equipment may include, but is not limited to, air compressors and pressure regulating valves.

[0070] In this embodiment of the invention, after receiving the cold start signal, a constant voltage graded current control strategy is adopted for the fuel cell stack. That is, the fuel cell stack voltage is controlled to fluctuate within the target value range by a DC / DC converter, the voltage is supplied to the fuel cell stack according to the preset voltage range, and the operation feedback of the fuel cell stack is detected in real time as the data basis for graded current control.

[0071] After detecting the operating feedback current, the operating feedback current is compared with a first preset current threshold to adjust the subsequent air inlet flow rate and control interval time.

[0072] Please see Figure 2 , Figure 2 This is a schematic diagram of an AC impedance monitoring structure in an embodiment of the present invention.

[0073] As fuel cell output power increases significantly (tens of kilowatts, hundreds of kilowatts, etc.), the number of stacks will reach hundreds, increasing the difficulty of controlling the consistency of individual stacks. Uneven distribution of reactant gas flow and temperature within the stack can easily lead to poor performance consistency of individual cells during startup, resulting in longer cold start times or even startup failure. Therefore, single-stack consistency has become a crucial factor affecting cold start. Firstly, for high-power batteries, real-time impedance monitoring of each single stack would require extensive acquisition circuits and signal processing chips. To reduce space requirements and system costs, a multi-channel AC impedance monitoring method was designed. The fuel cell stacks are divided into n zones, with each zone containing m stacks. Each zone is equipped with a signal acquisition and processing device connected to the m single stacks within that zone. A polling mode is used, and information from all n×m single stacks can be obtained through m iterations.

[0074] Step 102: If the operating feedback current is greater than the first preset current threshold, the air inlet flow rate of the fuel cell stack is adjusted according to the first preset hydrogen-air metering ratio until it is less than the first preset current threshold.

[0075] In one example of the present invention, step 102 may include the following sub-steps:

[0076] If the operating feedback current is greater than the first preset current threshold, the first initial flow rate of the fuel cell stack is calculated according to the preset control formula.

[0077] The mixed gas is input into the fuel cell stack according to the first initial flow rate and the first preset hydrogen-air metering ratio until the operating feedback current is less than the first preset current threshold.

[0078] The control formula is:

[0079]

[0080] in, Let k be the initial flow rate at time k. This is the proportional gain coefficient. This is the integral gain coefficient. The differential gain coefficient, This is the cumulative sum of all deviation values ​​from time 0 to time k. Current deviation value Deviation value from the previous time difference.

[0081] In this embodiment, changes in airflow have a relatively small impact on the open-circuit voltage of the fuel cell stack. However, under low airflow and high current density, a significant mass transfer limit point occurs, leading to decreased start-up performance and reduced fuel utilization. Therefore, in the first stage of start-up, a low-current state is set to maintain the fuel cell stack in a relatively high ramp-up state. When the feedback current I... 1aWhen I > I1, the air inlet flow rate is controlled by PID control until I 1a ≤I1 is used to extend the interval time to stabilize the open-circuit voltage of the fuel cell stack.

[0082] The first preset current threshold can be set to 100A, the second preset current threshold can be set to 200A, the first preset hydrogen-air metering ratio is hydrogen / air = 1.2 / 2, and the second preset hydrogen-air metering ratio is hydrogen / air = 0.8 / 2.

[0083] Step 103: Collect the operating feedback current at preset intervals;

[0084] In this embodiment, after a preset interval is reached, the operating feedback current is collected again to determine whether a second-stage adjustment of the air inlet flow rate is needed. As the fuel cell stack temperature increases, the required gas flow rate will also change. At this time, the secondary gas flow rate can be used as a control variable, and the output current can be controlled by PID to improve the fuel cell stack output performance.

[0085] Step 104: Adjust the air inlet flow rate of the fuel cell stack according to the comparison result of the operating feedback current and the second preset current threshold and the second preset hydrogen-air metering ratio until the fuel cell stack reaches the start-up temperature.

[0086] In one example of the present invention, step 104 may include the following sub-steps:

[0087] Compare the operating feedback current with the second preset current threshold;

[0088] If the operating feedback current is greater than the second preset current threshold, the second initial flow rate of the fuel cell stack is calculated according to the preset control formula.

[0089] Input the mixed gas according to the second initial flow rate and the second preset hydrogen-air metering ratio, and detect the current hydrogen column flow rate;

[0090] The bypass flow rate is calculated as the target value using the current hydrogen column flow rate combined with the split ratio formula.

[0091] Adjust the air inlet flow rate of the fuel cell stack according to the target value until the fuel cell stack reaches the start-up temperature.

[0092] In this embodiment, after the operating feedback current is obtained again, the operation feedback current is compared with the second preset current threshold to determine whether the stack temperature has entered the second stage. If the operating feedback current is greater than the second preset current value, it indicates that the gas flow rate needs to be adjusted. The second initial flow rate of the stack can be calculated according to the preset control formula, which can be found in the calculation process of the first initial flow rate described above, and will not be repeated here. After calculating the second initial flow rate, the mixed gas is input according to the second preset hydrogen-air metering ratio. At the same time, in order to ensure that the exhaust hydrogen concentration is below the safety threshold, it needs to be diluted by bypass air. According to the safety requirement that the exhaust hydrogen concentration ratio is less than 4%, the current hydrogen column flow rate is measured by gas chromatography using inlet air. According to the split ratio formula:

[0093] Flow split ratio = Column flow rate / (Column flow rate + Bypass flow rate)

[0094] The bypass flow rate is calculated (the specific flow rate is adjusted based on the fuel cell stack capacity and the hydrogen concentration in the gas under operating conditions). Finally, the calculated bypass flow rate is used as the target value, and the air compressor speed and pressure regulating valve opening are controlled by PID control to achieve safe control of the reaction gas pressure and flow rate.

[0095] Please see Figure 3 , Figure 3 A flowchart of a cold start control method according to an embodiment of the present invention is shown.

[0096] By examining the "concentration overpotential - air stoichiometric ratio" curves under different fuel cell stack currents, it was found that a smaller hydrogen-air stoichiometric ratio results in a larger concentration overpotential, more heat generation, and easier achievement of oxygen-stage self-heating. Therefore, during the cold start transient process, the concentration potential can be controlled by adjusting the hydrogen-air stoichiometric ratio. Specifically, this control method can be implemented using a constant voltage U... s The input voltage to the fuel cell stack is simultaneously adjusted according to the fuel cell stack voltage U. a Real-time detection of the real-time feedback current I of the fuel cell stack 1a Using this I 1a The air inlet flow rate is compared with the first preset current threshold I1, and adjusted according to the comparison result, while the feedback voltage U is also adjusted accordingly. s and U a The difference between them is used to adjust the hydrogen-air metering ratio until I... 1a ≤I1, at this point, after the interval time is reached, the real-time feedback current I is detected. 2a The air inlet flow rate is adjusted again based on the comparison result with the second preset current threshold I2. At the same time, the bypass flow rate is calculated based on the split ratio calculation formula to dilute the input mixed gas, thereby realizing the flow control of the fuel cell stack.

[0097] In one example of the present invention, the method further includes the following steps:

[0098] Detect the real-time voltage and real-time current of the fuel cell stack;

[0099] If the real-time voltage or real-time current does not reach the rated value, the process will jump to the step of collecting the operating feedback current at preset intervals.

[0100] In this embodiment, the stack voltage and current are monitored in real time. When the set value is not reached, the air inlet flow rate is readjusted based on the difference between the feedback current and the set current, and the bypass flow control is updated synchronously to ensure that the stack operates within a safe threshold, thus completing the stack start-up-operation closed-loop control.

[0101] In one example of the present invention, the method further includes the following steps:

[0102] When the fuel cell stack is shut down, the load on the fuel cell stack is reduced according to the preset load reduction slope until the temperature of the fuel cell stack drops to the first preset temperature.

[0103] Open the cathode tail valve of the fuel cell stack and adjust the three-way valve to humidify the air intake at the cathode and anode of the fuel cell stack.

[0104] Turn on the tail heater at the cathode exhaust end of the fuel cell stack;

[0105] Hydrogen gas with a first relative humidity is introduced into the anode of the fuel cell stack at a first preset flow rate, and air with a second relative humidity is introduced into the cathode of the fuel cell stack at a second preset flow rate and maintained for a preset time.

[0106] The shutdown purging strategy directly determines the consistency of water content within the fuel cell stack. During low-temperature purging, significant impedance differences exist between individual stacks, indicating variations in gas flow characteristics and resulting in inconsistent residual water content—that is, uneven water distribution. This inconsistent residual water content during shutdown purging can lead to the precipitation of supercooled water in some cells during cold storage, or even freezing at low temperatures. This can cause excessive temperature differences between stacks during startup, affecting the fuel cell's cold-start capability and potentially causing cold-start failure. Therefore, airflow, air pressure, and stack outlet water temperature are crucial factors influencing the purging effect. An optimization calibration strategy is adopted, where one variable is changed while others remain constant, to optimize the response variable. Post-shutdown purging is critical for fuel cells, effectively reducing internal moisture residue and ensuring sufficient reaction channels for gas flow during cold start. An optimal shutdown purging strategy is designed to ensure consistent impedance between individual stacks. The shutdown purging process for both the cathode and anode sides is as follows:

[0107] Shutdown preparation: Hydrogen-air metering ratio 1 / 2, stack temperature 650℃, anode humidification, cathode humidification, run for 10 minutes, then reduce load at a rate of 20A / s, and reduce the stack temperature to 600℃.

[0108] Purging: Maintain the fuel cell stack temperature at 600℃. Open the cathode tail exhaust valve and adjust the three-way valve to humidify the intake air at the cathode and anode. Turn on the tail exhaust heater at the cathode exhaust end to improve the effective range of the humidity sensor. Purge the anode with 30L / min of hydrogen gas at 50% relative humidity and the cathode with 400L / min of air at 50% relative humidity for 20 minutes.

[0109] Gas supply to the cathode and anode is stopped, and the cells are allowed to cool down. When the stack impedance is balanced, the impedance value of each individual stack is recorded.

[0110] Compared to single-sided purging, the shutdown preparation is as follows: hydrogen-to-air metering ratio 1 / 2, stack temperature 650℃, anode humidification, cathode non-humidification, run for 10 minutes, then reduce load at a rate of 20 A / s, and lower the stack temperature to 600℃. Purging: Maintain the stack temperature at 600℃, open the cathode exhaust valve, adjust the three-way valve to ensure the cathode air intake is non-humidified, and turn on the tail heater at the cathode exhaust end to improve the effective range of the humidity sensor. Purge the cathode with 400 L / min of dry air for 20 minutes. Stop the cathode air supply and allow it to cool down. When the stack impedance is balanced, record the impedance value of each individual stack.

[0111] Single-sided purging causes the battery's AC impedance to increase rapidly and eventually tend to change linearly, indicating that single-sided purging can rapidly reduce the water content inside the battery, but it will not tend to stabilize. On the other hand, when the cathode and anode are purged, the battery's AC impedance will show an overshoot phase, first increasing and then decreasing and eventually stabilizing. This can control the water content inside the battery at a stable level, which is beneficial for the cold start process.

[0112] In this embodiment of the invention, in response to a cold start signal, voltage is supplied to the fuel cell stack according to a preset voltage range, and the operating feedback current of the fuel cell stack is detected. If the operating feedback current is greater than a first preset current threshold, the air inlet flow rate of the fuel cell stack is adjusted according to a first preset hydrogen-air metering ratio until it is less than the first preset current threshold. The operating feedback current is collected at preset intervals. The air inlet flow rate of the fuel cell stack is adjusted according to the comparison result of the operating feedback current and a second preset current threshold and the second preset hydrogen-air metering ratio until the fuel cell stack reaches the start-up temperature, thereby enabling fast and convenient cold start control of the solid oxide fuel cell stack.

[0113] Please see Figure 4 , Figure 4 A structural block diagram of a cold start device for an electric stack based on single-stack consistency is shown in an embodiment of the present invention.

[0114] This invention provides a cold start device for fuel cell stacks based on single-stack consistency, comprising:

[0115] The real-time feedback current detection module 401 is used to respond to the cold start signal, deliver voltage to the fuel cell stack according to the preset voltage range, and detect the operating feedback current of the fuel cell stack.

[0116] The first flow adjustment module 402 is used to adjust the air inlet flow of the fuel cell stack according to the first preset hydrogen-air metering ratio if the operating feedback current is greater than the first preset current threshold, until it is less than the first preset current threshold.

[0117] The current re-acquisition module 403 is used to acquire the operating feedback current at preset intervals.

[0118] The second flow adjustment module 404 is used to adjust the air inlet flow of the fuel cell stack according to the comparison result of the operating feedback current and the second preset current threshold and the second preset hydrogen-air metering ratio, until the fuel cell stack reaches the start-up temperature.

[0119] Optionally, the device further includes:

[0120] The unloading module is used to unload the fuel cell stack according to a preset unloading slope when the stack is shut down, until the temperature of the stack drops to a first preset temperature.

[0121] The first opening module is used to open the cathode tail valve of the fuel cell stack and adjust the three-way valve to make the cathode and anode of the fuel cell stack humidified.

[0122] The second activation module is used to activate the tail heater at the cathode exhaust end of the fuel cell stack.

[0123] The gas inlet module is used to introduce hydrogen gas with a first relative humidity into the anode of the fuel cell stack at a first preset flow rate, and to introduce air with a second relative humidity into the cathode of the fuel cell stack at a second preset flow rate and maintain it for a preset time.

[0124] Optionally, the first flow adjustment module 402 is specifically used for:

[0125] If the operating feedback current is greater than the first preset current threshold, the first initial flow rate of the fuel cell stack is calculated according to the preset control formula.

[0126] The mixed gas is input into the fuel cell stack according to the first initial flow rate and the first preset hydrogen-air metering ratio until the operating feedback current is less than the first preset current threshold.

[0127] The control formula is:

[0128]

[0129] in, Let k be the initial flow rate at time k. This is the proportional gain coefficient. This is the integral gain coefficient. The differential gain coefficient, This is the cumulative sum of all deviation values ​​from time 0 to time k. Current deviation value Deviation value from the previous time difference.

[0130] Optionally, the second flow adjustment module 404 is specifically used for:

[0131] Compare the operating feedback current with the second preset current threshold;

[0132] If the operating feedback current is greater than the second preset current threshold, the second initial flow rate of the fuel cell stack is calculated according to the preset control formula.

[0133] Input the mixed gas according to the second initial flow rate and the second preset hydrogen-air metering ratio, and detect the current hydrogen column flow rate;

[0134] The bypass flow rate is calculated as the target value using the current hydrogen column flow rate combined with the split ratio formula.

[0135] Adjust the air inlet flow rate of the fuel cell stack according to the target value until the fuel cell stack reaches the start-up temperature.

[0136] Optionally, the device further includes:

[0137] The real-time detection module is used to detect the real-time voltage and real-time current of the fuel cell stack.

[0138] The cyclic adjustment module is used to jump to the step of collecting operating feedback current at preset intervals if the real-time voltage or real-time current does not reach the rated value.

[0139] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described device and module can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0140] In the several embodiments provided by this invention, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0141] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A single stack consistency based cold start method of a stack, characterized by, include: In response to a cold start signal, the system supplies voltage to the fuel cell stack according to a preset voltage range and detects the operating feedback current of the fuel cell stack. If the operating feedback current is greater than the first preset current threshold, the air inlet flow rate of the fuel cell stack is adjusted according to the first preset hydrogen-air metering ratio until it is less than the first preset current threshold. The operating feedback current is collected at preset intervals. Based on the comparison result between the operating feedback current and the second preset current threshold and the second preset hydrogen-air metering ratio, the air inlet flow rate of the fuel cell stack is adjusted until the fuel cell stack reaches the start-up temperature; wherein, the first preset current threshold is 100A, the second preset current threshold is 200A, the first preset hydrogen-air metering ratio is hydrogen / air = 1.2 / 2, and the second preset hydrogen-air metering ratio is hydrogen / air = 0.8 / 2; The step of adjusting the air inlet flow rate of the fuel cell stack according to the comparison result of the operating feedback current and the second preset current threshold and the second preset hydrogen-air metering ratio until the fuel cell stack reaches the start-up temperature includes: Compare the operating feedback current with the second preset current threshold; If the operating feedback current is greater than the second preset current threshold, then the second initial flow rate of the fuel cell stack is calculated according to the preset control formula; Input the mixed gas according to the second initial flow rate and the second preset hydrogen-air metering ratio, and detect the current hydrogen column flow rate; The bypass flow rate is calculated as the target value using the current hydrogen column flow rate combined with the split ratio formula. Adjust the air inlet flow rate of the fuel cell stack according to the target value until the fuel cell stack reaches the start-up temperature; The control formula is: ； wherein, is a second initial flow rate at time k, is a proportional gain coefficient, is an integral gain coefficient, is a differential gain coefficient, is a cumulative sum of all deviation values from time 0 to time k, is a current deviation value and a previous deviation value difference. The method further includes: The real-time voltage and real-time current of the fuel cell stack are detected; If the real-time voltage or the real-time current does not reach the rated value, then proceed to the step of collecting the operating feedback current at preset intervals.

2. The method according to claim 1, characterized in that, The method further includes: When the fuel cell stack is shut down, the fuel cell stack is deloaded according to a preset deload slope until the temperature of the fuel cell stack drops to a first preset temperature; Open the cathode tail valve of the fuel cell stack and adjust the three-way valve to humidify the air intake of the cathode and anode of the fuel cell stack. Turn on the tail heater at the cathode exhaust end of the fuel cell stack; Hydrogen gas with a first relative humidity is introduced into the anode of the fuel cell at a first preset flow rate, and air with a second relative humidity is introduced into the cathode of the fuel cell at a second preset flow rate and maintained for a preset time.

3. The method according to claim 1, characterized in that, If the operating feedback current is greater than a first preset current threshold, the air inlet flow rate of the fuel cell stack is adjusted according to a first preset hydrogen-air metering ratio until it is less than the first preset current threshold, including: If the operating feedback current is greater than the first preset current threshold, the first initial flow rate of the fuel cell stack is calculated according to the preset control formula. The mixed gas is input into the fuel cell stack according to the first initial flow rate and the first preset hydrogen-air metering ratio until the operating feedback current is less than the first preset current threshold. The control formula is: in, Let k be the initial flow rate at time k. This is the proportional gain coefficient. This is the integral gain coefficient. The differential gain coefficient, This is the cumulative sum of all deviation values ​​from time 0 to time k. Current deviation value Deviation value from the previous time difference.

4. A cold start device for an electric fuel cell stack based on single-stack consistency, characterized in that, include: The real-time feedback current detection module is used to respond to the cold start signal, deliver voltage to the fuel cell stack according to a preset voltage range, and detect the operating feedback current of the fuel cell stack. The first flow rate adjustment module is used to adjust the air inlet flow rate of the fuel cell stack according to the first preset hydrogen-air metering ratio if the operating feedback current is greater than the first preset current threshold, until it is less than the first preset current threshold. The current re-acquisition module is used to acquire the operating feedback current at preset intervals. The second flow adjustment module is used to adjust the air inlet flow of the fuel cell stack according to the comparison result of the operating feedback current and the second preset current threshold and the second preset hydrogen-air metering ratio, until the fuel cell stack reaches the start-up temperature; wherein, the first preset current threshold is 100A, the second preset current threshold is 200A, the first preset hydrogen-air metering ratio is hydrogen / air = 1.2 / 2, and the second preset hydrogen-air metering ratio is hydrogen / air = 0.8 / 2; The second flow adjustment module is specifically used for: Compare the operating feedback current with the second preset current threshold; If the operating feedback current is greater than the second preset current threshold, then the second initial flow rate of the fuel cell stack is calculated according to the preset control formula; Input the mixed gas according to the second initial flow rate and the second preset hydrogen-air metering ratio, and detect the current hydrogen column flow rate; The bypass flow rate is calculated as the target value using the current hydrogen column flow rate combined with the split ratio formula. Adjust the air inlet flow rate of the fuel cell stack according to the target value until the fuel cell stack reaches the start-up temperature; The control formula is: ； in, The second initial flow rate at time k, This is the proportional gain coefficient. This is the integral gain coefficient. The differential gain coefficient, This is the cumulative sum of all deviation values ​​from time 0 to time k. Current deviation value Deviation value from the previous time difference; The device further includes: A real-time detection module is used to detect the real-time voltage and real-time current of the fuel cell stack. The cyclic adjustment module is used to jump to the step of collecting the operating feedback current at preset intervals if the real-time voltage or the real-time current does not reach the rated value.

5. The apparatus according to claim 4, characterized in that, The device further includes: The unloading module is used to unload the fuel cell stack according to a preset unloading slope when the stack is shut down, until the temperature of the stack drops to a first preset temperature. The first opening module is used to open the cathode tail valve of the fuel cell stack and adjust the three-way valve to make the cathode and anode of the fuel cell stack humidified. The second activation module is used to activate the tail heater at the cathode exhaust end of the fuel cell stack. A gas inlet module is used to introduce hydrogen gas with a first relative humidity into the anode of the fuel cell stack at a first preset flow rate, and to introduce air with a second relative humidity into the cathode of the fuel cell stack at a second preset flow rate and maintain the flow for a preset time.

6. The apparatus according to claim 4, characterized in that, The first flow adjustment module is specifically used for: If the operating feedback current is greater than the first preset current threshold, the first initial flow rate of the fuel cell stack is calculated according to the preset control formula. The mixed gas is input into the fuel cell stack according to the first initial flow rate and the first preset hydrogen-air metering ratio until the operating feedback current is less than the first preset current threshold. The control formula is: in, Let k be the initial flow rate at time k. This is the proportional gain coefficient. This is the integral gain coefficient. The differential gain coefficient, This is the cumulative sum of all deviation values ​​from time 0 to time k. Current deviation value Deviation value from the previous time difference.

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