A hydrogen replacement system for fuel cells

Abstract

The present invention provides a hydrogen replacement system for fuel cells, which belongs to the field of fuel cell technology and solves the problem that a large amount of hydrogen is wasted and the replacement time is too long during replacement in the prior art. The device includes a fuel cell stack, a hydrogen supply device, a hydrogen exhaust valve and a replacement controller. The hydrogen inlet of the fuel cell stack is connected to the output end of the hydrogen supply device, and the hydrogen tail gas outlet is connected to the external tail exhaust pipe through the hydrogen exhaust valve. After receiving the replacement instruction, the replacement controller controls the hydrogen supply device to start and pass low-pressure hydrogen into the fuel cell stack. After monitoring that the pressure on the anode side of the fuel cell stack reaches the set value, the hydrogen exhaust valve is controlled to open according to the set rule and start timing until the timing time reaches the set time and the hydrogen exhaust valve is closed. The hydrogen supply device is then controlled to pass high-pressure hydrogen into the fuel cell stack until the replacement is completed. The system can ensure that the concentration of hydrogen discharged during the entire replacement process meets the national emission standards and effectively reduces the hydrogen replacement time.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a hydrogen replacement system and method for fuel cells. Background Art

[0002] Fuel cell operation requires high hydrogen quality. Harmful gases mixed in the incoming hydrogen can poison the catalysts within the stack. Insufficient hydrogen purity can cause localized hydrogen deficiency within the stack, leading to corrosion of the carbon support. These factors can all degrade fuel cell performance.

[0003] In the existing technology, during the startup phase of the fuel cell, pure hydrogen is generally used to fully replace the impurity gas on the anode side. After the hydrogen concentration on the anode side meets the standard, current is applied to prevent the hydrogen purity of the reaction from being insufficient. In the first half of the replacement, the hydrogen concentration in the stack is low, most of the exhaust gas is impurity gas, and the hydrogen concentration rises rapidly. In the second half, the hydrogen concentration in the stack is high, most of the exhaust gas is hydrogen, and the hydrogen concentration rises slowly. The second half takes too long, which not only increases the total hydrogen replacement time, but also causes a large amount of hydrogen to be wasted.

[0004] The second half of the replacement process requires a large air flow to dilute the exhaust gas. Since the air compressor can only provide a limited amount of air flow, to meet emission requirements, the replacement pressure is generally lowered to reduce the flow. This results in a longer replacement time, ultimately affecting the startup time and giving users a poor user experience. Summary of the Invention

[0005] In view of the above analysis, the embodiments of the present invention aim to provide a hydrogen replacement system and method for a fuel cell, so as to solve the problem in the prior art that a large amount of hydrogen is wasted during replacement and the replacement time is too long.

[0006] On the one hand, an embodiment of the present invention provides a hydrogen replacement system for a fuel cell, comprising a fuel cell stack, a hydrogen supply device, a hydrogen exhaust valve and a replacement controller; wherein,

[0007] The hydrogen inlet of the fuel cell stack is connected to the output end of the hydrogen supply device, and the hydrogen tail gas outlet is connected to the external tail exhaust pipe through the hydrogen exhaust valve;

[0008] The replacement controller is used to control the hydrogen supply device to start and introduce low-pressure hydrogen into the fuel cell stack after receiving the replacement instruction. After monitoring that the pressure on the anode side of the fuel cell stack reaches the set value, it controls the hydrogen discharge valve to open according to the set rule and starts the timing. The hydrogen discharge valve is closed until the timing reaches the set time, and the hydrogen supply device is controlled to introduce high-pressure hydrogen into the fuel cell stack until the replacement is completed.

[0009] The beneficial effects of the above technical solution are as follows: The hydrogen replacement system ensures that the concentration of hydrogen emitted during the entire replacement process meets national emission standards, thereby ensuring safe vehicle startup. Under the control of the replacement controller, low-pressure hydrogen provided by the hydrogen supply device expels most of the impurities in the fuel cell stack before high-pressure hydrogen is introduced. This effectively avoids the hydrogen waste during startup caused by existing replacement strategies, improves the hydrogen replacement speed, reduces the hydrogen replacement time, and thus shortens the startup time of the fuel cell engine.

[0010] Based on the further improvement of the above system, the hydrogen replacement system also includes a hydrogen circulation device; and,

[0011] The hydrogen discharge valve has two output ends, one of which is connected to an external tail discharge pipe, and the other is connected to a circulation loop inlet of a hydrogen supply device through a hydrogen circulation device;

[0012] The control end of the hydrogen circulation device is connected to the output end of the displacement controller.

[0013] Furthermore, the replacement controller further comprises:

[0014] A data acquisition unit is used to obtain the current gas pressure on the anode side of the fuel cell stack and send it to the data processing and control unit;

[0015] The data processing and control unit is used to control the hydrogen supply device to start and introduce low-pressure hydrogen in the range of 30~70kPa into the fuel cell stack after receiving the replacement instruction, and monitor the gas pressure on the anode side of the fuel cell stack to reach the set value that minimizes the total replacement time. P 1, control the hydrogen discharge valve to open according to the set rule and start the timing until the timing reaches the set time and close the hydrogen discharge valve. Then control the hydrogen supply device again to introduce 100~150kPa high-pressure hydrogen into the fuel cell stack until the replacement is completed and issue an instruction that the hydrogen replacement is completed.

[0016] Furthermore, the data acquisition unit further includes:

[0017] The gas pressure sensor entering the stack is located at the hydrogen inlet of the fuel cell stack and is used to obtain the hydrogen pressure entering the stack in real time.

[0018] The outgoing gas pressure sensor is installed at the hydrogen tail gas outlet of the fuel cell stack and is used to obtain the outgoing hydrogen tail gas pressure in real time as the anode side gas pressure of the fuel cell stack.

[0019] Furthermore, the data processing and control unit executes the following program:

[0020] After receiving the replacement instruction, the hydrogen supply device is started and the hydrogen supply device is controlled to inject the pressure into the fuel cell stack to the set value. P 1 of low-pressure hydrogen;

[0021] During the ventilation process, real-time monitoring is performed to see whether the gas pressure on the anode side of the stack reaches the set value that minimizes the replacement time. P 1. Once the set value is reached P 1. Execute the next step, otherwise, continue monitoring;

[0022] Control the hydrogen discharge valve to open according to the set rule and start the timing. When the timing reaches the set time, close the hydrogen discharge valve;

[0023] Control the hydrogen supply device to inject pressure into the fuel cell stack to the target value P 2 high pressure hydrogen;

[0024] During the ventilation process, real-time monitoring is performed to see whether the gas pressure on the anode side of the stack reaches the target value indicating that the replacement is complete. P 2. Once reached, issue a replacement completion instruction; otherwise, continue monitoring.

[0025] Furthermore, the data processing and control unit obtains the set value through the following procedure P 1:

[0026] According to the current hydrogen pressure entering the stack and the hydrogen concentration on the anode side of the stack, the hydrogen concentration on the anode side of the switching point that makes the total replacement time the shortest is determined. C 1;

[0027] According to the hydrogen concentration on the anode side at the switching point C 1. Combined with the characterization of the target hydrogen concentration after replacement C 2. Determine the setting value that minimizes the replacement time using the following formula P 1:

[0028] P 1=( P 2× C 2- P 2) / ( C 1-1)

[0029] Where, P 2 is the upper limit of the hydrogen-air pressure difference of the fuel cell stack, and is also the target value indicating that the replacement is complete.

[0030] Furthermore, the data processing and control unit also controls the start-up of the hydrogen circulation device while executing the step of controlling the start-up of the hydrogen supply device, so as to accelerate the flow and exhaust of impurity gases in the fuel cell stack.

[0031] Furthermore, the hydrogen replacement system also includes an explosion-proof housing; wherein,

[0032] The explosion-proof shell adopts a hollow structure and has a chamber inside that can be placed with a hydrogen supply device, a hydrogen circulation device, and a hydrogen exhaust valve. One side of the shell is provided with at least one hydrogen inlet for connecting to an external hydrogen bottle and at least one hydrogen outlet for communicating with a tail exhaust pipe, and the opposite side is provided with a hydrogen inlet and a hydrogen outlet for connecting to the fuel cell stack.

[0033] Furthermore, the data processing and control unit has a display module; wherein,

[0034] The display screen of the display module displays the current hydrogen pressure entering the stack, the gas pressure on the anode side of the stack, and information on whether the replacement is completed.

[0035] Furthermore, the hydrogen supply device further includes an air intake throttle valve and a hydrogen spray valve connected in sequence.

[0036] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0037] 1. First, use low-pressure hydrogen to replace hydrogen until the hydrogen concentration on the anode side of the stack reaches the switching point corresponding to the shortest replacement time. C 1. Close the hydrogen exhaust valve to stop replacement.

[0038] 2. After stopping the replacement, control the hydrogen supply device to provide high-pressure hydrogen to the fuel cell stack until the hydrogen concentration on the anode side of the fuel cell stack reaches the target value. C 2. Replacement completed.

[0039] 3. The replacement process of the fuel cell engine is monitored in real time through the set gas pressure sensor.

[0040] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the disclosure, nor is it intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present disclosure.

[0042] Figure 1 A schematic diagram of the composition of a hydrogen replacement system for a fuel cell in Example 1 is shown;

[0043] Figure 2 A schematic diagram of a control method for a hydrogen replacement system for a fuel cell in Example 1 is shown;

[0044] Figure 3A schematic diagram of the main components of the hydrogen replacement system for a fuel cell in Example 2 is shown.

[0045] Reference numerals:

[0046] 1- Fuel cell stack; 2- Hydrogen supply device; 3- Hydrogen exhaust valve; 4- Hydrogen circulation device; 5- Stack gas pressure sensor. DETAILED DESCRIPTION

[0047] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0048] As used herein, the term "including" and its variations represent open inclusion, i.e., "including but not limited to." Unless otherwise stated, the term "or" means "and / or." The term "based on" means "based at least in part on." The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment." The term "another embodiment" means "at least one additional embodiment." The terms "first," "second," etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0049] Example 1

[0050] One embodiment of the present invention discloses a hydrogen replacement system for a fuel cell, such as Figure 1 As shown, it includes a fuel cell stack, a hydrogen supply device, a hydrogen exhaust valve and a replacement controller.

[0051] The hydrogen inlet of the fuel cell stack is connected to the output end of the hydrogen supply device, and the hydrogen tail gas outlet is connected to the external tail exhaust pipe through the hydrogen exhaust valve.

[0052] The hydrogen supply device is used to provide the reactor inlet gas mainly composed of hydrogen.

[0053] The hydrogen exhaust valve is used to discharge the hydrogen tail gas leaving the stack into the atmosphere through the tail exhaust pipe according to the control of the replacement controller.

[0054] The replacement controller is used to control the start-up of the hydrogen supply device and the introduction of low-pressure hydrogen into the fuel cell stack after receiving the replacement instruction. After monitoring that the pressure on the anode side of the fuel cell stack has reached the set value, it controls the hydrogen exhaust valve to open according to the set rule and starts the timing until the timing reaches the set time and closes the hydrogen exhaust valve. It also controls the hydrogen supply device to introduce high-pressure hydrogen into the fuel cell stack until the replacement is completed (the sign of the completion of the replacement can be the set time, the monitoring that the pressure on the anode side of the fuel cell stack has reached the target value indicating that the replacement is completed, and the hydrogen concentration on the anode side of the fuel cell stack has reached the target value indicating that the replacement is completed). The replacement completion instruction is transmitted to the fuel cell engine controller on the whole vehicle so that it can start normally.

[0055] The aforementioned fuel cell hydrogen replacement system is suitable for hydrogen fuel cell engines. Generally, a hydrogen replacement system only requires a pressure monitoring device, eliminating the need for a concentration monitoring device. The concentration monitoring device can be used during the calibration test phase to determine the target value set within the pressure monitoring device, indicating the completion of the replacement.

[0056] Optionally, the hydrogen replacement system may further include other components configured according to specific functions, such as a silencer component, a hydrogen adsorption component, etc. Those skilled in the art will understand this and will not be elaborated on herein.

[0057] When implementing, if Figure 2 As shown, after the fuel cell engine enters the hydrogen replacement stage during startup, the hydrogen supply device is started to supply low-pressure hydrogen to the anode side until the anode side pressure reaches the set pressure. P 1 (corresponding to a certain hydrogen concentration), control the hydrogen discharge valve to open according to the set rules to discharge hydrogen, and the cumulative time reaches the set value T After (the time required to fully discharge impurities), close the hydrogen discharge valve; continue to open the hydrogen supply device to supply high-pressure hydrogen to the fuel cell stack until the hydrogen replacement is completed, and continue to execute the subsequent startup process.

[0058] The above setting value T It can be determined through test calibration.

[0059] Compared to existing technologies, the hydrogen replacement system provided in this embodiment ensures that the concentration of hydrogen emitted during the entire replacement process meets national emission standards, thereby ensuring safe vehicle startup. Under the control of the replacement controller, low-pressure hydrogen provided by the hydrogen supply device expels most of the impurity gases within the fuel cell stack before high-pressure hydrogen is introduced. This effectively avoids the hydrogen waste during startup caused by existing replacement strategies, speeds up hydrogen replacement, reduces hydrogen replacement time, and ultimately shortens the startup time of the fuel cell engine.

[0060] Example 2

[0061] Based on the improvement of Example 1, the fuel cell hydrogen replacement system also includes a hydrogen circulation device, such as Figure 3 shown.

[0062] The hydrogen exhaust valve has two output ends, one of which is connected to an external tail exhaust pipe, and the other is connected to a circulation loop inlet of a hydrogen supply device through a hydrogen circulation device.

[0063] The input end of the hydrogen circulation device is connected to the second output end of the hydrogen exhaust valve, its output end is connected to the circulation loop inlet of the hydrogen supply device, and its control end is connected to the output end of the displacement controller. The hydrogen supply device is started at the same time to accelerate the circulation speed and emptying speed of the gas in the fuel cell stack.

[0064] Preferably, the replacement controller further comprises a data acquisition unit and a data processing and control unit which are connected in sequence.

[0065] The data acquisition unit is used to obtain the current gas pressure on the anode side of the fuel cell stack and send it to the data processing and control unit.

[0066] The data processing and control unit is used to control the hydrogen supply device to start and introduce 30~70kPa low-pressure hydrogen into the fuel cell stack after receiving the replacement instruction, and monitor the gas pressure on the anode side of the fuel cell stack to reach the set value that minimizes the total replacement time. P 1, control the hydrogen discharge valve to open according to the set rule and start the timing until the timing reaches the set time and close the hydrogen discharge valve. Then control the hydrogen supply device again to introduce 100~150kPa high-pressure hydrogen into the fuel cell stack until the replacement is completed and issue an instruction that the hydrogen replacement is completed.

[0067] Preferably, the low pressure hydrogen can be set to a set value P 1. High-pressure hydrogen can set the target value P 2, so that the gas pressure on the anode side of the stack is stable in the later stage of each control, that is, during the opening of the hydrogen discharge valve, the gas pressure on the anode side of the stack is kept at P 1. After the hydrogen exhaust valve is closed, the gas pressure on the anode side of the stack is maintained at P 2.

[0068] Optionally, the setting schedule can be customized based on actual needs. For example, a fixed or variable duty cycle can be used, with the switch on for a period of time and off for a period of time, or it can be always on. The criteria for selecting the setting schedule are short replacement time and that the hydrogen concentration emitted to the atmosphere does not exceed the standard.

[0069] Preferably, the hydrogen discharge valve is set in a control mode of opening for 1.8 seconds within a 2 second period.

[0070] Preferably, the data acquisition unit further includes an inlet gas pressure sensor, an outlet gas pressure sensor, and a hydrogen concentration sensor.

[0071] The gas pressure sensor entering the stack is installed at the hydrogen inlet of the fuel cell stack and is used to obtain the hydrogen pressure entering the stack in real time.

[0072] The outgoing gas pressure sensor is installed at the hydrogen tail gas outlet of the fuel cell stack and is used to obtain the outgoing hydrogen tail gas pressure in real time as the anode side gas pressure of the fuel cell stack.

[0073] The hydrogen concentration sensor is installed at the hydrogen exhaust outlet of the fuel cell stack and is used to obtain the hydrogen concentration on the anode side of the fuel cell stack in real time.

[0074] Preferably, the data processing and control unit executes the following program:

[0075] S1. After receiving the replacement instruction, perform a tightness test on the fuel cell hydrogen replacement system; if the tightness test result is qualified, proceed to the next step; otherwise, repair the connecting pipes of the fuel cell hydrogen replacement system;

[0076] For example, only the hydrogen circulation device is started to allow gas to circulate on the anode side of the stack. Hydrogen concentration sensors arranged outside each pipeline are used to detect whether there is hydrogen leakage in the pipeline. If the hydrogen concentration collected by each hydrogen concentration sensor is 0 or lower than the set value, the air tightness test result is determined to be qualified. Otherwise, the pipeline with hydrogen leakage is replaced or the interface is further fixed until the air tightness test result is qualified.

[0077] S2. Start the hydrogen supply device and control the hydrogen supply device to supply pressure into the fuel cell stack to the set value P 1 of low-pressure hydrogen;

[0078] S3. During the ventilation process, monitor in real time whether the gas pressure on the anode side of the stack reaches the set value that minimizes the replacement time. P 1. Once the set value is reached P 1. Execute the next step, otherwise, continue monitoring;

[0079] Specifically, the setting value P 1 There are two ways to obtain it. The first is that R&D personnel determine a more appropriate pressure value through calibration trial and error. The second is to obtain it according to the calculation method of the subsequent steps S01~S02;

[0080] S4. Control the hydrogen discharge valve to open according to the set rule and start the timing. When the timing reaches the set value T (Set value T After obtaining the information (which can be obtained through calibration or calculation), close the hydrogen discharge valve;

[0081] S5. Control the hydrogen supply device to inject pressure into the fuel cell stack to the target value P 2 high pressure hydrogen;

[0082] S6. During the ventilation process, monitor in real time whether the gas pressure on the anode side of the stack reaches the target value indicating that the replacement is complete. P 2. Once reached, issue a replacement completion instruction; otherwise, continue monitoring.

[0083] Specifically, the target value P 2 is a value set by R&D personnel that is lower than the upper limit of the stack voltage to protect the stack.

[0084] Preferably, the data processing and control unit determines the setting value in step S3 by the following procedure: P 1:

[0085] S01. Determine the switching point anode hydrogen concentration that minimizes the total replacement time based on the current hydrogen pressure entering the stack and the hydrogen concentration on the anode side of the stack. C 1;

[0086] Specifically, the hydrogen concentration on the anode side at the switching point can be obtained by a trained neural network or laboratory calibration. C 1;

[0087] S02. According to the hydrogen concentration on the anode side at the switching point C 1. Combined with the characterization of the target hydrogen concentration after replacement C 2 (target value C 2) Determine the setting value that minimizes the replacement time using the following formula: P 1:

[0088] P 1=( P 2× C 2- P 2) / ( C 1-1)

[0089] Where, P 2 is the upper limit of the withstand voltage of the hydrogen-air pressure difference of the fuel cell stack, and is also the target value preferably used in this embodiment to indicate that the replacement is complete.

[0090] The theoretical derivation process is: according to the air flow that the system can provide, calculate the flow rate of hydrogen that can be diluted by this air flow, and reversely infer the set value based on the hydrogen flow rate. P 1.

[0091] Getting the set value P 1 and target value P 2, calculate the target concentration of the displacement C 1

[0092] C 1=( P 2× C 2- P 2+P 1) / P 1

[0093] Target value C 2 is the final concentration value to be achieved. This value is determined by the capacity of the fuel cell stack and is generally provided by the fuel cell stack manufacturer.

[0094] Preferably, the data processing and control unit controls the start-up of the hydrogen circulation device while executing step S4 to control the hydrogen exhaust valve to open according to a set rule, so as to accelerate the discharge of impurity gases in the fuel cell stack.

[0095] Preferably, the data processing and control unit also controls the start-up of the hydrogen circulation device while executing step S5 to restart the hydrogen supply device, so as to accelerate the circulation speed of the gas in the fuel cell stack.

[0096] Preferably, the hydrogen replacement system further includes an explosion-proof housing.

[0097] Among them, the explosion-proof shell adopts a hollow structure, with a chamber inside that can be placed in a hydrogen supply device, a hydrogen circulation device, and a hydrogen exhaust valve. One side of the shell is provided with at least one hydrogen inlet for connecting to an external hydrogen bottle and at least one hydrogen outlet for connecting to the tail exhaust pipe, and the opposite side is provided with a hydrogen inlet and a hydrogen outlet for connecting to the fuel cell stack.

[0098] Preferably, the data processing and control unit has a display module, wherein the display screen of the display module displays the current hydrogen pressure entering the stack, the gas pressure on the anode side of the stack, the hydrogen concentration on the anode side of the stack, and information on whether the replacement is completed.

[0099] Preferably, the hydrogen supply device further includes an air intake throttle valve and a hydrogen spray valve connected in sequence.

[0100] Preferably, the hydrogen circulation device includes a circulation pump and a hydrogen ejector. The circulation pump's input is connected to the fuel cell stack's hydrogen tail gas outlet, and its output is connected to the ejector's inlet. The ejector's jet inlet is connected to the hydrogen jet output, and its output is connected to the fuel cell stack's hydrogen inlet.

[0101] Compared with the prior art, the hydrogen replacement system for fuel cells provided in this embodiment has the following beneficial effects:

[0102] 1. First, use low-pressure hydrogen to replace hydrogen until the hydrogen concentration on the anode side of the stack reaches the switching point corresponding to the shortest replacement time. C 1. Close the hydrogen exhaust valve to stop replacement.

[0103] 2. After stopping the replacement, control the hydrogen supply device to provide high-pressure hydrogen to the fuel cell stack until the hydrogen concentration on the anode side of the fuel cell stack reaches the target value. C 2. Replacement completed.

[0104] 3. The replacement process of the fuel cell engine is monitored in real time through the set gas pressure sensor and hydrogen concentration sensor.

[0105] While various embodiments of the present disclosure have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or improvements over the prior art, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A hydrogen replacement system for a fuel cell, characterized in that: It includes a fuel cell stack, a hydrogen supply device, a hydrogen exhaust valve and a replacement controller; wherein, The hydrogen inlet of the fuel cell stack is connected to the output end of the hydrogen supply device, and the hydrogen tail gas outlet is connected to the external tail exhaust pipe through the hydrogen exhaust valve; The replacement controller is configured to, upon receiving a replacement instruction, control the hydrogen supply device to start and introduce low-pressure hydrogen into the fuel cell stack; after monitoring that the pressure on the anode side of the fuel cell stack reaches a set value, control the hydrogen discharge valve to open according to a set rule and start timing; close the hydrogen discharge valve until the timing reaches the set time, and control the hydrogen supply device to introduce high-pressure hydrogen into the fuel cell stack until the replacement is completed; the replacement controller further comprises: A data acquisition unit is used to obtain the current gas pressure on the anode side of the fuel cell stack and send it to the data processing and control unit; The data processing and control unit is configured to, upon receiving a replacement instruction, control the hydrogen supply device to start and introduce 30-70 kPa low-pressure hydrogen into the fuel cell stack; after monitoring that the pressure on the anode side of the fuel cell stack reaches the set value P1 that minimizes the total replacement time, control the hydrogen discharge valve to open according to a set rule and start timing until the timing reaches the set time, close the hydrogen discharge valve, and again control the hydrogen supply device to introduce 100-150 kPa high-pressure hydrogen into the fuel cell stack until the replacement is completed, and issue an instruction indicating that the hydrogen replacement is completed; the data acquisition unit further includes: The inlet gas pressure sensor is located at the hydrogen inlet of the fuel cell stack and is used to obtain the inlet hydrogen pressure in real time. The outgoing gas pressure sensor is located at the hydrogen tail gas outlet of the fuel cell stack and is used to obtain the outgoing hydrogen tail gas pressure in real time as the anode side gas pressure of the fuel cell stack. The data processing and control unit executes the following program: After receiving the replacement instruction, the hydrogen supply device is started and controlled to supply low-pressure hydrogen with a set pressure of P1 into the fuel cell stack; During the ventilation process, monitor in real time whether the gas pressure on the anode side of the stack reaches the set value P1 corresponding to the shortest replacement time. Once the set value P1 is reached, proceed to the next step; otherwise, continue monitoring. Control the hydrogen discharge valve to open according to the set rule and start the timing. When the timing reaches the set time, close the hydrogen discharge valve; Controlling the hydrogen supply device to introduce high-pressure hydrogen with a target pressure of P2 into the fuel cell stack; During the ventilation process, the gas pressure on the anode side of the stack is monitored in real time to see if it reaches the target value P2 indicating that the replacement is complete. Once it reaches the target value, an instruction indicating that the replacement is complete is issued; otherwise, monitoring continues.

2. The hydrogen replacement system for fuel cells according to claim 1, characterized in that: Also includes a hydrogen circulation device; and, The hydrogen discharge valve has two output ends, one of which is connected to an external tail discharge pipe, and the other is connected to a circulation loop inlet of a hydrogen supply device through a hydrogen circulation device; The control end of the hydrogen circulation device is connected to the output end of the displacement controller.

3. The hydrogen replacement system for fuel cells according to claim 1, characterized in that: The data processing and control unit obtains the set value P1 through the following procedure: Determine the switching point anode side hydrogen concentration C1 that minimizes the total replacement time based on the current hydrogen pressure entering the stack and the hydrogen concentration on the anode side of the stack; Based on the hydrogen concentration C1 on the anode side at the switching point and the target hydrogen concentration C2 indicating the completion of the replacement, the set value P1 that minimizes the replacement time is determined by the following formula: P1=(P2×C2-P2) / (C1-1) In the formula, P2 is the upper limit of the hydrogen-air pressure difference of the fuel cell stack, and is also the target value indicating that the replacement is complete.

4. The hydrogen replacement system for fuel cells according to claim 3, characterized in that: The data processing and control unit also controls the start-up of the hydrogen circulation device while executing the step of controlling the start-up of the hydrogen supply device, so as to accelerate the flow and exhaust of impurity gases in the fuel cell stack.

5. The hydrogen replacement system for a fuel cell according to any one of claims 1 to 4, characterized in that: Also includes an explosion-proof housing; wherein, The explosion-proof shell adopts a hollow structure and has a chamber inside that can be placed with a hydrogen supply device, a hydrogen circulation device, and a hydrogen exhaust valve. One side of the shell is provided with at least one hydrogen inlet for connecting to an external hydrogen bottle and at least one hydrogen outlet for communicating with a tail exhaust pipe, and the opposite side is provided with a hydrogen inlet and a hydrogen outlet for connecting to the fuel cell stack.

6. The hydrogen replacement system for a fuel cell according to any one of claims 1 to 4, characterized in that: The data processing and control unit has a display module; wherein, The display screen of the display module displays the current hydrogen pressure entering the stack, the gas pressure on the anode side of the stack, and information on whether the replacement is completed.

7. The hydrogen replacement system for a fuel cell according to any one of claims 1 to 4, characterized in that: The hydrogen supply device further includes an air intake throttle valve and a hydrogen spray valve connected in sequence.

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