Start-up purging method and system for abnormal shutdown of fuel cell

Abstract

The invention discloses a start-up purging method and system for abnormal shutdown of a fuel cell, and the method mainly comprises the steps: firstly judging whether the last shutdown of an engine is normal shutdown during start-up, if the last shutdown is not normal shutdown, generating a special purging signal, and starting a fuel cell purging mechanism for special purging according to the special purging signal; meanwhile, whether the engine has an internal resistance monitoring function or not is judged, if the engine has the internal resistance monitoring function, the purging strength is improved, and a fuel cell purging mechanism is stopped after internal resistance meets the requirement of a fuel cell; if the internal resistance monitoring function does not exist, when the purging duration reaches the calibrated purging duration maximum value, stopping the fuel cell purging mechanism; and after the purging is completed, the fuel cell normally operates to generate power. Therefore, the abnormal condition of the last shutdown can be judged before starting, and residual water in the fuel cell is blown out of the hydrogen cavity and the cavity, so that damage caused by non-uniform heat production of an electric pile in the starting and loading process is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and particularly to a starting purge method and system for abnormal shutdown of a fuel cell. Background Art

[0002] During the normal shutdown process of a fuel cell engine, there is a purge stage to prevent the liquid water generated by the reaction from remaining inside the engine after shutdown. However, during the actual operation of the fuel cell engine, the engine may enter an emergency stop without being able to perform a normal shutdown operation. Once an emergency stop occurs, it means that the shutdown purge stage is extremely short or even unable to enter the purge stage. If the engine has been running for a long time and a large amount of water is generated by the reaction of hydrogen and oxygen inside the fuel cell stack, there will be liquid water in the hydrogen chamber, cavity, components, and even pipelines inside the fuel cell stack, which may cause flooding of the fuel cell stack and pose a great safety hazard to the next normal startup. Summary of the Invention

[0003] Aiming at the above deficiencies, the technical problem to be solved by the present invention is: to provide a starting purge method and system for abnormal shutdown of a fuel cell. Before starting the engine, it is necessary to determine whether the previous shutdown was normal. If it was an abnormal shutdown, necessary purging is performed to drain the excess water in the cavity and hydrogen chamber of the fuel cell, avoiding uneven heat generation in the fuel cell stack during the starting and loading process and causing damage.

[0004] To solve the above technical problem, the technical solution of the present invention is:

[0005] A starting purge method for abnormal shutdown of a fuel cell includes the following steps:

[0006] S10. Determine whether the previous shutdown of the engine was a normal shutdown;

[0007] S20. If the previous shutdown was not a normal shutdown, generate a corresponding special purge signal;

[0008] S30. According to the special purge signal, start the fuel cell purge mechanism for special purging;

[0009] S40. Determine whether the engine has an internal resistance monitoring function;

[0010] S50. If it has an internal resistance monitoring function, increase the purge intensity and stop the fuel cell purge mechanism after the internal resistance reaches the requirements of the fuel cell;

[0011] If it does not have an internal resistance monitoring function, stop the fuel cell purge mechanism when the purge duration reaches the maximum value of the calibrated purge duration.

[0012] Preferably, if there is no internal resistance monitoring in S50, when the purging duration reaches the maximum value of the calibrated purging duration, the step of stopping the fuel cell purging mechanism includes:

[0013] If there is no internal resistance monitoring function, obtain the operating intensity of the fuel cell within time t before the last shutdown;

[0014] Obtain the maximum value of the calibrated purging duration according to the operating intensity;

[0015] When the purging duration reaches the maximum value of the purging duration, stop the fuel cell purging mechanism.

[0016] Preferably, the calibration of the maximum value of the purging duration includes:

[0017] Step 1: Control the engine to operate under a certain working condition, and then cause the engine to shut down abnormally under the current working condition;

[0018] Step 2: After restarting, start the fuel cell purging mechanism for special purging, and record the purging duration;

[0019] Step 3: Monitor the internal resistance through the engine internal resistance meter. When the internal resistance meets the requirements of the fuel cell, stop the fuel cell purging mechanism to obtain the purging duration, and this purging duration is used as the maximum value of the purging duration;

[0020] Step 4: Obtain the operating intensity within time t before the abnormal shutdown;

[0021] Step 5: Store the calibration data under this working condition. The calibration data includes the operating intensity and the maximum value of the purging duration;

[0022] Step 6: Select n different working conditions, and repeat Steps 1 to 5 to obtain n groups of calibration data.

[0023] Preferably, the fuel cell purging mechanism includes a hydrogen pipeline, a hydrogen pump, a drain valve, and an air compressor; the outlet of the hydrogen pipeline is connected to the inlet of the electric propulsion hydrogen chamber, the outlet end of the hydrogen pump is connected to the inlet of the electric propulsion hydrogen chamber, the inlet end of the hydrogen pump is connected to one outlet of the drain valve, the inlet of the drain valve is connected to the fuel cell stack, the other outlet of the drain valve is connected to the tail exhaust pipe, and the inlet of the tail exhaust pipe is connected to the outlet of the fuel cell stack; the outlet of the air compressor is connected to the inlet of the fuel cell stack cavity.

[0024] Preferably, the calibration of the maximum value of the purging duration further includes:

[0025] The fourth step further includes: obtaining the operating intensity, the hydrogen pipeline pressure p, the hydrogen pump speed r0, the drain valve opening time t, and the air compressor speed r1 within time t before the abnormal shutdown;

[0026] Step five further includes: storing the calibration data under this operating condition, where the calibration data includes the operating intensity, the hydrogen pipeline pressure p, the hydrogen pump speed r0, the drainage valve opening time t, the air compressor speed r1, and the maximum purging duration.

[0027] Preferably, increasing the purging intensity in S50 includes:

[0028] Increasing the hydrogen pipeline pressure p, the hydrogen pump speed r0, the drainage valve opening time t, and / or the air compressor speed r1.

[0029] Preferably, S10 includes:

[0030] Judging whether a shutdown signal was transmitted before the engine's last shutdown;

[0031] Judging whether the fuel cell high voltage lost power before the engine's last shutdown;

[0032] If a shutdown signal was not transmitted before the engine's last shutdown, or the fuel cell high voltage lost power before the engine's last shutdown, then the engine's last shutdown was not a normal shutdown.

[0033] A startup purging system for abnormal shutdown of a fuel cell includes a control unit, an abnormal shutdown detection unit, a fuel cell purging mechanism, and a purging control unit that are electrically connected to the control unit respectively;

[0034] The abnormal shutdown detection unit is used to judge whether the engine's last shutdown was a normal shutdown, and transmit a detection signal corresponding to normal shutdown or abnormal shutdown to the control unit;

[0035] After receiving the detection signal corresponding to abnormal shutdown, the control unit starts the fuel cell purging mechanism for special purging, and at the same time starts the purging control unit;

[0036] The purging control unit is used to start timing the purging duration, and at the same time obtain the operating intensity within the t time before shutdown, and then obtain the corresponding maximum purging duration according to the operating intensity. When the purging duration reaches the calibrated maximum purging duration, it controls the fuel cell purging mechanism to stop.

[0037] Preferably, the system further includes a presetting unit, and the presetting unit is used to preset the operating intensity and the corresponding maximum purging duration, the hydrogen pipeline pressure p, the hydrogen pump speed r0, the drainage valve opening time t, and the air compressor speed r1.

[0038] Preferably, when the engine has an internal resistance monitoring function, the purging control unit is further used to control the fuel cell purging mechanism to increase the purging intensity, and stop the fuel cell purging mechanism after the internal resistance reaches the fuel cell requirement.

[0039] After adopting the above technical solution, the beneficial effects of the present invention are as follows:

[0040] Since the start-up purge method and system for abnormal shutdown of the fuel cell of the present invention mainly determine whether the engine's last shutdown was a normal shutdown during start-up. If the last shutdown was not a normal shutdown, a special purge signal is generated. According to the special purge signal, the fuel cell purge mechanism is started for special purging; at the same time, it is judged whether the engine has an internal resistance monitoring function. If it has an internal resistance monitoring function, the purge intensity is increased, and after the internal resistance reaches the requirements of the fuel cell, the fuel cell purge mechanism is stopped; if it does not have an internal resistance monitoring function, when the purge duration reaches the maximum value of the calibrated purge duration, the fuel cell purge mechanism is stopped; after purging is completed, the fuel cell generates electricity normally. It can be seen that the present invention can judge the abnormal situation of the last shutdown before start-up, first blow out the residual water in the fuel cell from the hydrogen chamber and the cavity, and avoid damage caused by uneven heat generation of the stack during the start-up load process. Description of the Drawings

[0041] Figure 1 is a schematic flow chart of the start-up purge method for abnormal shutdown of the fuel cell in the present invention;

[0042] Figure 2 is a schematic diagram of the fuel cell purge mechanism in the present invention;

[0043] Figure 3 is a schematic block diagram of the start-up purge system for abnormal shutdown of the fuel cell in the present invention;

[0044] In the figure: 1 - stack, 2 - hydrogen pipeline, 3 - pressure regulating valve, 4 - hydrogen pump, 5 - drain valve, 6 - tail exhaust pipe, 7 - back pressure valve, 8 - air compressor, 9 - stop valve. Detailed Embodiments

[0045] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] It should be noted that in the description of the present invention, the terms indicating directions or positional relationships such as "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings. This is only for convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention.

[0047] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] Embodiment 1:

[0049] As Figure 1 shown, a method for starting and purging a fuel cell during abnormal shutdown includes the following steps:

[0050] Step S10: Determine whether the engine's last shutdown was a normal shutdown; in this embodiment, it can be determined by whether the high voltage of the fuel cell dropped before the engine's last shutdown; if no shutdown signal was transmitted before the engine's last shutdown, or the high voltage of the fuel cell dropped before the engine's last shutdown, then the engine's last shutdown was not a normal shutdown. Of course, the method for judging abnormal engine shutdown is not limited to those listed above.

[0051] Step S20: If the last shutdown was not a normal shutdown, generate a corresponding special purging signal;

[0052] Step S30: According to the special purging signal, start the fuel cell purging mechanism for special purging;

[0053] Step S40: Determine whether the engine has an internal resistance monitoring function; usually, the engine uses an internal resistance meter to monitor the internal resistance.

[0054] Step S50: If the engine has an internal resistance monitoring function, increase the purging intensity, and stop the fuel cell purging mechanism after the internal resistance reaches the requirements of the fuel cell; in the present invention, by increasing the purging intensity, the purging duration is shortened to meet other starting requirements of the engine; and increasing the purging intensity can include increasing the purging hydrogen pressure, the rotational speed of the hydrogen pump, the rotational speed of the air compressor, etc. It should be noted that: the internal resistance reaching the requirements of the fuel cell specifically means that the internal resistance reading is consistent with the normal shutdown required internal resistance of the fuel cell stack.

[0055] If the engine does not have an internal resistance monitoring function, stop the fuel cell purging mechanism when the purging duration reaches the maximum value of the calibrated purging duration, that is, control the fuel cell purging mechanism by monitoring the special purging duration.

[0056] After adopting the start-up purge method for abnormal shutdown of the fuel cell of the present invention, it is possible to judge the abnormal situation of the previous shutdown before starting up. If the previous shutdown is a normal shutdown, normal start-up can be carried out after starting up. If the previous shutdown is an abnormal shutdown, at this time, the fuel cell purge mechanism is started for special purging. First, the residual water in the fuel cell is blown out of the hydrogen chamber and the cavity to avoid damage caused by uneven heat generation of the stack during the start-up load process. After blowing out the residual water, the fuel cell operates normally to generate electricity. Moreover, the start-up purge method of the present invention has the advantages of simple operation, low cost and easy implementation, and can be widely put into use.

[0057] In step S50 of this embodiment, it specifically includes the following steps:

[0058] If the engine itself does not have an internal resistance monitoring function, obtain the operating intensity of the fuel cell within t time before the previous shutdown; where t can be but is not limited to 0.5 hours, and the operating intensity can be but is not limited to the generated electricity of the fuel cell in the 0.5 hours before shutdown.

[0059] According to the operating intensity, obtain the maximum calibrated purge duration;

[0060] When the purge duration reaches the maximum calibrated purge duration, stop the fuel cell purge mechanism.

[0061] The present invention automatically controls the stop of the fuel cell purge mechanism through the maximum calibrated purge duration, and ensures that the residual water in the hydrogen chamber and the cavity in the stack is reliably blown out.

[0062] As Figure 2 shown, the fuel cell purge mechanism used in the present invention includes a hydrogen pipeline 2, a pressure regulating valve 3, a hydrogen pump 4, a drain valve 5 and an air compressor 8 provided on the hydrogen pipeline 2; the outlet of the hydrogen pipeline 2 is connected to the inlet of the stack hydrogen chamber, the outlet end of the hydrogen pump 4 is connected to the hydrogen pipeline 2, the inlet end of the hydrogen pump 4 is connected to one outlet of the drain valve 5, the inlet of the drain valve 5 is connected to the stack 1, the other outlet of the drain valve 5 is connected to the tail exhaust pipe 6, the inlet of the tail exhaust pipe 6 is connected to the outlet of the stack 1, and a back pressure valve 7 is provided on the tail exhaust pipe 6; the outlet of the air compressor 8 is connected to the inlet of the stack cavity, and a stop valve 9 is provided on the pipeline between the air compressor 8 and the stack cavity.

[0063] When the fuel cell purge mechanism is started, external hydrogen passes through the hydrogen pipeline 2 and enters the stack hydrogen chamber to blow the residual water in the hydrogen chamber. At the same time, the air compressor 8 is started, and air enters the stack cavity to blow the residual water in the cavity. After the residual water in the stack 1 is blown and moved to the outlet of the drain valve 5, when the drain valve 5 is opened, it is discharged through the drain valve 5 and the tail exhaust pipe 6, and the residual hydrogen in the hydrogen chamber enters the stack hydrogen chamber again through the drain valve 5 for purging to achieve reuse.

[0064] The calibration of the maximum purge duration in the present invention includes the following steps:

[0065] Step 1: Control the engine to operate under a certain working condition, and remanufacture the abnormal shutdown of the engine under the current working condition.

[0066] Step 2: After restarting, start the fuel cell purging mechanism for special purging, and record the purging duration.

[0067] Step 3: Monitor the internal resistance through an engine internal resistance meter. When the internal resistance meets the requirements of the fuel cell, stop the fuel cell purging mechanism to obtain the purging duration, and this purging duration is used as the maximum purging duration.

[0068] Step 4: Obtain the operating intensity within the t time before the abnormal shutdown; in this embodiment, obtain the operating intensity, hydrogen pipeline pressure p, hydrogen pump speed r0, drainage valve opening time t, and air compressor speed r1 within the t time before the abnormal shutdown.

[0069] Step 5: Store the calibration data under this working condition. The calibration data includes the operating intensity and the maximum purging duration; in this embodiment, the calibration data also includes the hydrogen pipeline pressure p, hydrogen pump speed r0, drainage valve opening time t, and air compressor speed r1. That is, in the calibration stage, the operating parameters of the fuel cell purging mechanism are determined through experiments to ensure that the fuel cell purging mechanism can purge reliably and avoid damaging the stack, such as controlling the hydrogen pipeline pressure p to be less than the maximum value, etc.

[0070] Step 6: Select n different working conditions, and repeat Steps 1 to 5 to obtain n groups of calibration data, where n can be but is not limited to 10. In addition, the calibration data can be stored in the form of a table.

[0071] Before the calibration data of the present invention is put into use, it is verified in combination with the actual application scenario and then applied to ensure the reliability of use.

[0072] In order to obtain the calibration data, the specific operations of the present invention are as follows:

[0073] Internal equipment such as an internal resistance meter is connected to the stack inside the engine. Select n working conditions to operate and create an emergency stop or abnormal purging shutdown. The role of the n working conditions is to provide a variable of the operating intensity in the half hour before the emergency stop; subsequently, calibrate the longest startup time under different working conditions (the total operating intensity in the half hour before the emergency stop). The purging method before startup can use the hydrogen pipeline to provide gas with a pressure of p1 (this value needs to ensure the safety of the stack), the hydrogen pump speed r0, the drainage valve opening time t, the air inlet stop valve of the air path, and the tail exhaust back pressure valve are fully open, and the air compressor speed r1.

[0074] Read the internal resistance meter reading during the purging process, and it is sufficient that it is consistent with the internal resistance required for normal shutdown of the stack, and then determine the maximum purging time.

[0075] To meet the requirement of quick engine start-up, such as shortening the purging duration, the hydrogen pipeline pressure, hydrogen pump speed, drain valve opening time, and air compressor speed can be increased according to the operating intensity before shutdown. When the engine can monitor the internal resistance and reaches the required internal resistance value of the fuel cell stack but has not reached the maximum start-up purging time, the start-up purging process can be ended and the subsequent start-up stage can be entered immediately. If the engine cannot monitor the internal resistance, it can be executed according to the calibrated data.

[0076] Based on the fuel cell purging mechanism used in the present invention, the enhancement of the purging intensity in step S50 can specifically be: increasing the hydrogen pipeline pressure p, hydrogen pump speed r0, drain valve opening time t, and / or air compressor speed r1. By enhancing the purging intensity, the purging duration can be shortened to meet the engine start-up requirements.

[0077] In summary, when the engine makes an emergency stop or abnormal shutdown during high-intensity operation, it cannot enter the purging stage, resulting in a risk of waterlogging in the hydrogen chamber and cavity. After adopting the method of the present invention, it is possible to judge the abnormal shutdown situation of the previous shutdown before starting the engine, first blow out the residual water from the hydrogen chamber and cavity, and avoid uneven heat generation in the stack during the start-up loading process, thereby ensuring the reliability of the fuel cell.

[0078] Embodiment 2:

[0079] As Figure 2 and Figure 3 shown, a start-up purging system for abnormal shutdown of a fuel cell can apply the start-up purging method for abnormal shutdown of a fuel cell described in Embodiment 1. The start-up purging system includes a control unit and an abnormal shutdown detection unit, a fuel cell purging mechanism, a purging control unit, and a preset unit that are electrically connected to the control unit respectively. The fuel cell purging mechanism specifically includes the structure described in Embodiment 1.

[0080] The abnormal shutdown detection unit is used to judge whether the engine's previous shutdown is a normal shutdown, and transmit the detection signal corresponding to normal shutdown or abnormal shutdown to the control unit. If no shutdown signal is transmitted before the engine's previous shutdown, or the fuel cell high voltage drops before the engine's previous shutdown, both belong to the abnormal shutdown situation of the engine.

[0081] When the control unit receives the detection signal corresponding to abnormal shutdown, it starts the fuel cell purging mechanism for special purging and starts the purging control unit at the same time.

[0082] The purging control unit is used to start timing the purging duration, and at the same time obtain the operating intensity within time t before shutdown. Then, according to the operating intensity, the maximum purging duration corresponding thereto is obtained. When the purging duration reaches the calibrated maximum purging duration, the fuel cell purging mechanism is controlled to stop. The purging control unit is also used to control the fuel cell purging mechanism to increase the purging intensity when the engine has an internal resistance monitoring function. After the internal resistance reaches the requirements of the fuel cell, the fuel cell purging mechanism is stopped. Specifically, increasing the purging intensity means increasing the hydrogen pipeline pressure p, the hydrogen pump speed r0, the drainage valve opening time t, and / or the air compressor speed r1.

[0083] The presetting unit is used to preset the operating intensity and the corresponding maximum purging duration, the hydrogen pipeline pressure p, the hydrogen pump speed r0, the drainage valve opening time t, and the air compressor speed r1. Specifically, the presetting unit can perform presetting by using the calibration method of the maximum purging duration described in Embodiment 1.

[0084] As Figure 3 shown, for the startup purging system of the fuel cell with abnormal shutdown of the present invention, after startup and power-on, the abnormal shutdown detection unit detects and judges whether the engine's last shutdown was a normal shutdown. When the engine's last shutdown was a normal shutdown, the control unit enters normal startup operation. When the engine's last shutdown was an abnormal shutdown, the control unit starts the fuel cell purging mechanism for special purging, and at the same time starts the purging control unit to time the purging duration. When the control unit receives the detection signal corresponding to the abnormal shutdown, it obtains the operating intensity of the fuel cell half an hour before shutdown, and according to the operating intensity, obtains the corresponding maximum purging duration, and transmits the maximum purging duration to the purging control unit.

[0085] When the engine itself has an internal resistance monitoring function, when the internal resistance reading reaches the requirements of the fuel cell stack, the purging control unit only needs to stop the fuel cell purging mechanism, and there is no need to purge until the calibrated maximum purging duration is reached. When the engine itself does not have an internal resistance monitoring function, when the purging duration reaches the maximum purging duration, the purging control unit controls the fuel cell purging mechanism to stop.

[0086] It can be seen that the startup purging system of the fuel cell with abnormal shutdown of the present invention can judge the abnormal situation of the last shutdown before startup, and first blow out the residual water from the hydrogen cavity and the cavity, avoiding uneven heat generation of the stack during the startup and loading process and damage, thereby ensuring the reliability of the fuel cell.

[0087] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for starting and purging a fuel cell during abnormal shutdown, characterized in that: The following steps are involved: S10, determining whether the last shutdown of the engine was a normal shutdown; S20, if the last shutdown was not a normal shutdown, generate a corresponding special purge signal; S30, starting the fuel cell purge mechanism to perform special purge according to the special purge signal; S40, determining whether the engine has an internal resistance monitoring function; S50, if the internal resistance monitoring function is provided, the purge intensity is increased, and after the internal resistance reaches the fuel cell requirement, the fuel cell purge mechanism is stopped; If the internal resistance monitoring function is not provided, the fuel cell purge mechanism is stopped when the purge time reaches the calibrated maximum purge time.

2. The startup purging method for abnormal shutdown of a fuel cell according to claim 1, characterized in that: If there is no internal resistance monitoring in S50, when the purge time reaches the calibrated maximum purge time, the step of stopping the fuel cell purge mechanism includes: If there is no internal resistance monitoring function, obtain the operation intensity of the fuel cell within t time before the last shutdown; According to the operation intensity, the maximum value of the calibrated purge time is obtained; When the purge time reaches the maximum purge time, the fuel cell purge mechanism is stopped.

3. The startup purging method for abnormal shutdown of a fuel cell according to claim 1, characterized in that: The calibration of the maximum purge time includes: Step 1: Control the engine to operate under a certain working condition, and then create an abnormal shutdown of the engine under the current working condition; Step 2: After restarting, start the fuel cell purge mechanism to perform special purge and record the purge duration; Step 3: Monitor the internal resistance through the engine internal resistance meter. When the internal resistance meets the requirements of the fuel cell, stop the fuel cell purge mechanism and obtain the purge time, which is used as the maximum purge time. Step 4: Obtain the operation intensity within t time before the abnormal shutdown; Step 5: storing calibration data under the working condition, the calibration data including the maximum value of the operating intensity and the purge duration; Step 6: Select n different working conditions and repeat steps 1 to 5 to obtain n sets of calibration data.

4. The startup purging method for abnormal shutdown of a fuel cell according to claim 3, characterized in that: The fuel cell purge mechanism includes a hydrogen pipeline, a hydrogen pump, a drain valve and an air compressor; The gas outlet of the hydrogen pipeline is connected to the inlet of the electric propulsion hydrogen chamber, the gas outlet end of the hydrogen pump is connected to the inlet of the electric propulsion hydrogen chamber, the gas inlet end of the hydrogen pump is connected to an outlet of the drain valve, the inlet of the drain valve is connected to the fuel cell stack, the other outlet of the drain valve is connected to the tail pipe, and the inlet of the tail pipe is connected to the outlet of the fuel cell stack; The air outlet of the air compressor is connected to the inlet of the fuel cell stack cavity.

5. The startup purging method for abnormal shutdown of a fuel cell according to claim 4, characterized in that: The calibration of the maximum purge duration also includes: The step 4 also includes: obtaining the operation intensity, hydrogen pipeline pressure p, hydrogen pump speed r0, drain valve opening time t and air compressor speed r1 within the time t before the abnormal shutdown; The step five also includes: storing calibration data under the working condition, the calibration data including operation intensity, hydrogen pipeline pressure p, hydrogen pump speed r0, drain valve opening time t, air compressor speed r1 and maximum purge time.

6. The startup purging method for abnormal shutdown of a fuel cell according to claim 4, characterized in that: Increasing the purge intensity in S50 includes: Increase the hydrogen pipeline pressure p, hydrogen pump speed r0, drain valve opening time t and / or air compressor speed r1.

7. The startup purging method for abnormal shutdown of a fuel cell according to claim 1, characterized in that: The S10 includes: Determine whether a shutdown signal was transmitted before the engine was last shut down; Determine whether the high voltage of the fuel cell was disconnected before the engine was shut down last time; If the shutdown signal was not transmitted before the engine was last stopped, or the high voltage of the fuel cell was disconnected before the engine was last stopped, the last shutdown of the engine was not a normal shutdown.

8. A startup purge system for abnormal shutdown of a fuel cell, characterized in that: It includes a control unit and an abnormal shutdown detection unit, a fuel cell purge mechanism and a purge control unit which are electrically connected to the control unit respectively; The abnormal shutdown detection unit is used to determine whether the last shutdown of the engine was a normal shutdown, and transmit a detection signal corresponding to a normal shutdown or an abnormal shutdown to the control unit; After receiving the detection signal corresponding to the abnormal shutdown, the control unit starts the fuel cell purge mechanism to perform special purge, and simultaneously starts the purge control unit; The purge control unit is used to start timing the purge duration, and at the same time obtain the operating intensity within t time before shutdown, and then obtain the corresponding maximum purge duration according to the operating intensity. When the purge duration reaches the calibrated maximum purge duration, the fuel cell purge mechanism is controlled to stop.

9. The startup purge system for abnormal shutdown of a fuel cell according to claim 8, characterized in that: The system further comprises a preset unit, which is used to preset the operation intensity and the corresponding maximum purge time, hydrogen pipeline pressure p, hydrogen pump speed r0, drain valve opening time t and air compressor speed r1.

10. The startup purge system for abnormal shutdown of a fuel cell according to claim 8, characterized in that: The purge control unit is also used to control the fuel cell purge mechanism to increase the purge intensity when the engine has an internal resistance monitoring function, and to stop the fuel cell purge mechanism after the internal resistance reaches the fuel cell requirement.

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