Purging control method and device for hydrogen-oxygen fuel cell

Abstract

The invention discloses an oxyhydrogen fuel cell purging control method and device, and the method comprises the steps: introducing air into a bypass pipeline to dilute the emission concentration of hydrogen during hydrogen purging; hydrogen is introduced into a hydrogen cavity of the electric pile, purging is carried out for a target duration, and the purged hydrogen is discharged from an exhaust and drainage valve; after the hydrogen cavity is purged for the target duration, pressure maintaining is conducted on the hydrogen cavity; closing the bypass pipeline, and enabling air to enter the cathode to perform in-pile purging; obtaining the voltage of a single battery in the electric pile and the voltage of a DCDC input end; and if the voltage of the single cell in the electric pile, the voltage of the DCDC input end and the total purging duration meet the operation conditions, the hydrogen-oxygen fuel cell starts to carry out current loading. Therefore, by adopting a hydrogen-air step-by-step purging strategy, the total duration of the overpotential can be greatly shortened, and by adopting a DCDC discharge mode, oxygen in the reactor is consumed and the overvoltage is lowered while hydrogen purging is carried out.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen-oxygen fuel cells, and in particular to a hydrogen-oxygen fuel cell purge control method and device. Background Art

[0002] A hydrogen-oxygen fuel cell is an electrochemical reaction device. Its basic principle is the reverse reaction of water electrolysis. Hydrogen and oxygen are supplied to the anode and cathode respectively, and water is generated by the reaction of hydrogen and oxygen, converting chemical energy into electrical energy, and at the same time, into heat energy with efficiency loss. In order to ensure that the fuel cell will not be partially flooded due to water accumulation when it is started, and to discharge the impurity gas in the stack, the fuel cell is generally purged during the shutdown and startup process.

[0003] The long-term existence of overpotential generated during the conventional no-load purge process will lead to more serious carbon corrosion of the bipolar plates in the fuel cell stack. At present, weakening carbon corrosion and reducing the hydrogen-air interface is one of the important directions for improving the durability of hydrogen fuel cells.

[0004] The existing technology mainly purges the hydrogen cavity and the air cavity synchronously, and controls the high-voltage electric control DCF to realize the external load current of the stack to reduce the duration of the single cell voltage overpotential of the stack. The load current is calculated by fuzzy PID control. The purging achieved by this method is indeed effective in reducing the overpotential, but there is a disadvantage that the power control calculation is relatively complicated. In addition, if the current is directly loaded during the start-up purging, there is a risk of irreversible damage to the stack if the operation is improper. In addition, the above method is to purge hydrogen and air at the same time, which effectively reduces the overpotential problem while also causing the problem of increased hydrogen consumption. Summary of the invention

[0005] In view of the above problems, the present invention is proposed to provide a hydrogen-oxygen fuel cell purge control method and device, which can achieve startup purge with lower hydrogen consumption cost.

[0006] According to a first aspect of the present invention, a hydrogen-oxygen fuel cell purge control method is provided, comprising:

[0007] Air is introduced into the bypass line to dilute the emission concentration of hydrogen during hydrogen purge;

[0008] Introduce hydrogen into the hydrogen chamber of the fuel cell stack and purge for a target time, and the purged hydrogen is discharged from the exhaust and drain valve;

[0009] After the hydrogen cavity is purged for a target time, the hydrogen cavity is pressurized;

[0010] Close the bypass line to allow air to enter the cathode for purge inside the stack;

[0011] The voltage of a single cell in the stack and the voltage of the DCDC input terminal are obtained; if the voltage of a single cell in the stack, the voltage of the DCDC input terminal and the total purge time meet the operating conditions, the hydrogen and oxygen fuel cell starts to load the current.

[0012] Optionally, the step of introducing hydrogen into the hydrogen chamber of the fuel cell stack and performing a purge for a target time, wherein the purged hydrogen is discharged from an exhaust and drain valve, comprises:

[0013] Open the hydrogen inlet valve and the exhaust and drain valve;

[0014] Determine the opening of the hydrogen inlet proportional valve according to the preset hydrogen pressure;

[0015] Set a target duration for hydrogen purge in the fuel cell stack;

[0016] Hydrogen is introduced into the hydrogen chamber of the fuel cell stack, and hydrogen purge is performed for a target time, and the purged hydrogen is discharged from the exhaust and drain valve.

[0017] Optionally, the step of introducing air into the bypass line to dilute the emission concentration of hydrogen during hydrogen purge includes:

[0018] Open the air compressor and bypass pipeline valve, close the air intake valve and back pressure valve of the air chamber, and introduce air into the bypass pipeline to dilute the emission concentration of hydrogen during hydrogen purging.

[0019] Optionally, after the step of introducing hydrogen into the fuel cell stack, performing hydrogen purge for a target time, and discharging the purged hydrogen from the exhaust and drain valve, the method further comprises:

[0020] Obtain the hydrogen inlet pressure and the average cell voltage of each battery in the stack;

[0021] If the hydrogen inlet pressure and the average cell voltage of each battery in the battery stack meet the discharge conditions, the DCDC is controlled to be in the discharge mode;

[0022] Optionally, if the hydrogen inlet pressure and the average cell voltage of each battery in the battery stack meet the discharge condition, controlling the DCDC to be in the discharge mode includes:

[0023] If the difference between the hydrogen inlet pressure and the preset target pressure is within the target range, and the average cell voltage of each battery in the battery stack is greater than the voltage threshold, the DCDC is controlled to be in the discharge mode.

[0024] Optionally, maintaining the pressure of the hydrogen cavity includes:

[0025] Close the exhaust and drain valves, keep the hydrogen inlet valve open, and adjust the opening of the hydrogen inlet proportional valve through PID according to the preset target pressure to maintain the required pressure of the hydrogen chamber.

[0026] Optionally, closing the bypass pipeline to allow air to enter the cathode for purge in the stack includes:

[0027] The air compressor is maintained at a preset speed, the air intake valve of the air cavity is opened, the bypass pipeline valve is closed, and the opening of the back pressure valve is adjusted to maintain a constant hydrogen-air pressure difference, so that air enters the cathode for purge in the stack.

[0028] Optionally, if the voltage of a single cell in the stack, the voltage at the DCDC input terminal, and the total purge time meet the operating conditions, the hydrogen-oxygen fuel cell starts to load current, including:

[0029] If the lowest voltage among the single-cell voltages in the stack is greater than a first threshold, the DCDC input voltage is greater than a second threshold, and the total purge duration is greater than a duration threshold, the fuel cell starts current loading.

[0030] According to a second aspect of the present invention, there is provided a hydrogen-oxygen fuel cell purge control device, comprising:

[0031] The first purge module is used to introduce air into the bypass pipeline to dilute the emission concentration of hydrogen during hydrogen purge; introduce hydrogen into the hydrogen chamber of the fuel cell stack and purge for a target time, and the purged hydrogen is discharged from the exhaust and drain valve;

[0032] A pressure-maintaining module, used for maintaining the pressure of the hydrogen cavity after the hydrogen cavity is purged for a target time;

[0033] The second purge module is used to close the bypass pipeline to allow air to enter the cathode for purge inside the stack;

[0034] The acquisition module is used to obtain the voltage of a single cell in the battery stack and the voltage of the DCDC input terminal;

[0035] The operation module is used to start current loading for the hydrogen and oxygen fuel cell when the voltage of a single cell in the battery stack, the voltage at the DCDC input terminal, and the total purge time meet the operation conditions.

[0036] According to a third aspect of the present invention, a hydrogen-oxygen fuel cell is provided. When the stack of the hydrogen-oxygen fuel cell is purged, the aforementioned hydrogen-oxygen fuel cell purging control method is applied.

[0037] The above one or more technical solutions in the embodiments of this specification have at least the following technical effects:

[0038] The embodiment of this specification provides a hydrogen-oxygen fuel cell purge control method and device, which dilutes the emission concentration of hydrogen during hydrogen purge by introducing air into the bypass line; introduces hydrogen into the hydrogen chamber of the stack, and purges for a target time, and the purged hydrogen is discharged from the exhaust and drain valve; after the hydrogen chamber is purged for a target time, the hydrogen chamber is pressurized; the bypass line is closed to allow air to enter the cathode for purge in the stack; the voltage of a single cell in the stack and the voltage of the DCDC input terminal are obtained; if the voltage of a single cell in the stack, the voltage of the DCDC input terminal and the total purge time meet the operating conditions, the hydrogen-oxygen fuel cell starts to load current. In this way, the hydrogen-air step-by-step purge strategy can greatly shorten the total duration of the overpotential, and the DCDC discharge mode is used to consume oxygen in the stack and lower the overvoltage while purging hydrogen.

[0039] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Also, throughout the accompanying drawings, the same reference figures are used to represent the same components. In the drawings:

[0041] Figure 1 A hydrogen-oxygen fuel cell purge control method in an embodiment of the present invention is shown.

[0042] Figure 2 A schematic diagram of a hydrogen-oxygen fuel cell in an embodiment of the present invention is shown.

[0043] Figure 3 A block diagram of a hydrogen-oxygen fuel cell purge control device in an embodiment of the present invention is shown.

[0044] S100-Hydrogen-oxygen fuel cell stack

[0045] S101-Hydrogen Inlet Valve

[0046] S102-Hydrogen inlet proportional valve

[0047] S103-Exhaust and drain valve

[0048] S104-Air compressor

[0049] S105-Bypass line valve

[0050] S106-Intake valve

[0051] S107-Back Pressure Valve

[0052] S200-DCDC DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0054] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0056] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] The embodiment of the present invention provides a hydrogen-oxygen fuel cell purge control method, combining Figure 1 The method includes steps 101 to 105:

[0058] Step 101: introducing air into the bypass line to dilute the emission concentration of hydrogen during hydrogen purge;

[0059] In this embodiment, the hydrogen chamber and the air chamber are purged step by step. The hydrogen chamber is located on the anode side, and the air chamber is located on the cathode side. The method of this embodiment is applied in a hydrogen-oxygen fuel cell. Specifically, in combination with Figure 2As shown, on the hydrogen side, the hydrogen inlet valve S101, the hydrogen inlet proportional valve S102, and the hydrogen-oxygen fuel cell stack S100 are connected in sequence. On the air side, the air compressor S104, the air inlet valve S106, and the hydrogen-oxygen fuel cell stack S100 are connected in sequence. One end of the bypass line valve S105 is connected to the air compressor S104, and the other end is connected to the back pressure valve S107. The back pressure valve S107 and the exhaust and drain valve S103 are respectively connected to the hydrogen-oxygen fuel cell stack S100. S200DCDC (DC-DC converter) is connected to the hydrogen-oxygen fuel cell stack S100.

[0060] In this embodiment, the hydrogen chamber is first purged.

[0061] First, open the air compressor S104 and the bypass line valve S105; close the air intake valve S106 and the back pressure valve S107 of the air chamber to dilute the emission concentration of hydrogen during hydrogen purge.

[0062] Step 102: hydrogen is introduced into the hydrogen chamber of the fuel cell stack, and purged for a target time, and the purged hydrogen is discharged from the exhaust and drain valve;

[0063] In this embodiment, hydrogen is introduced into the hydrogen cavity on the anode side to purge the stack for a target time. The specific steps may include:

[0064] Open the hydrogen inlet valve S101 and the exhaust and drain valve S103;

[0065] According to the preset hydrogen pressure, determine the opening of the hydrogen inlet proportional valve S102;

[0066] Set a target duration for hydrogen purge in the fuel cell stack;

[0067] Hydrogen is introduced into the hydrogen chamber of the fuel cell stack, and hydrogen is purged for a target time, and the purged hydrogen is discharged from the exhaust and drain valve S103.

[0068] The target duration can be set within the range of 5-8 seconds. The preset hydrogen pressure is 25kpa. The opening of the hydrogen inlet proportional valve is adjusted by PID.

[0069] Hydrogen enters from the hydrogen inlet valve S101, passes through the hydrogen inlet proportional valve S102, enters the hydrogen-oxygen fuel cell stack S100, and is then discharged from the exhaust and drain valve S103. The discharged hydrogen mixes with the air in the bypass pipeline, thereby reducing the emission concentration of hydrogen.

[0070] It should be noted that during the hydrogen purge process, if the air tightness of the hydrogen-oxygen fuel cell system is poor or the system has been parked for a long time, air from the outside may remain in the stack. When hydrogen is introduced into the stack for purge, an open circuit voltage will appear, and sometimes even an overpotential higher than 1V will appear.

[0071] Based on the above situation, this embodiment designs the following strategies:

[0072] Obtain the hydrogen inlet pressure and the average cell voltage of each battery in the stack;

[0073] If the hydrogen inlet pressure and the average cell voltage of each battery in the battery stack meet the discharge conditions, the DCDC is controlled to be in the discharge mode;

[0074] That is, the hydrogen inlet pressure and the average single-chip voltage are judged, when the difference between the hydrogen inlet pressure and the preset target pressure is within the target range, that is, the hydrogen inlet pressure is close to the target pressure;

[0075] At the same time, if the average cell voltage of each battery in the battery stack is greater than the voltage threshold, the DCDC discharge mode is turned on to reduce the open circuit voltage. When the above conditions are not met, the DCDC discharge mode remains turned off.

[0076] The target pressure is 25 kPa and the voltage threshold is 0.85 V. The DCDC discharge mode refers to the process in which when the input voltage of the DCDC is higher than 36 V, the power is consumed through the internal resistance of the DCDC to reduce the voltage.

[0077] The DCDC discharge mode stops when the voltage at the DCDC input terminal is less than 36V or the time exceeds 30 seconds.

[0078] Step 103: After the hydrogen cavity is purged for a target time, the hydrogen cavity is pressurized;

[0079] In this embodiment, after the hydrogen chamber is purged, the anode side starts to maintain pressure, that is, the hydrogen chamber is pressurized. By closing the exhaust and drainage valve S103, the hydrogen inlet valve S101 remains open, and the hydrogen inlet proportional valve S102 adjusts the opening through PID according to the preset target pressure to maintain the required pressure of the hydrogen chamber at 25kPa.

[0080] Step 104: close the bypass pipeline to allow air to enter the cathode for purge inside the stack;

[0081] At this time, the air compressor needs to maintain a preset speed. Open the air intake valve S106 of the air chamber, close the bypass line valve S105, and adjust the opening of the back pressure valve S107 to maintain a constant hydrogen-air pressure difference. The hydrogen-air pressure difference refers to the pressure difference between the hydrogen chamber side and the air chamber side.

[0082] In this embodiment, the pressure on one side of the air cavity is 10 kPa, and the pressure on one side of the hydrogen cavity maintains a pressure difference of 10-15 kPa with the pressure on one side of the air cavity (the pressure on the hydrogen cavity side is greater than that on the air cavity side).

[0083] And keeping the DCDC discharge mode turned on in this step has the advantage that maintaining the discharge mode is equivalent to having a continuous small current load, which can suppress the potential from being too high and can suppress the open circuit voltage to a certain extent.

[0084] Step 105: Obtain the voltage of a single cell in the stack and the voltage of the DCDC input terminal; if the voltage of a single cell in the stack, the voltage of the DCDC input terminal and the total purge time meet the operating conditions, the hydrogen and oxygen fuel cell starts to load the current.

[0085] In this embodiment, satisfying the operating conditions means:

[0086] When the lowest voltage among all the single-cell voltages in the stack is greater than the first threshold, the DCDC input voltage is greater than the second threshold, and the total purge time is greater than the time threshold, the fuel cell starts to load the current.

[0087] The first threshold and the second threshold are related to the parameters of the hydrogen-oxygen fuel cell and the parameters of the DCDC, and the parameters are different for different models.

[0088] In this embodiment, the first threshold may be 0.65 V, and the second threshold may be 260 V. The total purge duration refers to the sum of the target duration of the hydrogen purge and the air purge duration.

[0089] In summary, the DCDC discharge mode is used to suppress overpotential during hydrogen purging and consume residual oxygen in the stack. After the discharge mode is turned on, the average single-chip voltage shows a downward trend, and when the voltage is lower than a certain value, the discharge mode will be turned off immediately to prevent damage to the stack due to lack of oxygen loading; using the DCDC discharge mode, small current loading can be performed more safely, and it is protected by the DCDC's own controller. Most DCDCs have undervoltage protection in the discharge mode, and will not overload and damage the stack in this state.

[0090] The adoption of a hydrogen-air step-by-step purge strategy can greatly shorten the total duration of overpotential. During the hydrogen purge process, theoretically, if there is no air inside the stack, no open-circuit voltage will be formed. Even if air leaks into the stack, the voltage will be suppressed to a lower value using the DCDC discharge mode, so it can be considered that there is no overpotential phenomenon in the hydrogen purge step.

[0091] When air is purged into the stack, since the anode side is open to maintain pressure, hydrogen and air in the stack react to form an open circuit voltage. At this time, the discharge mode can suppress the higher potential downward. Different DCDCs have different discharge current settings, and the degree of suppression of the average voltage is also different. The open circuit voltage only exists in this process, and the average voltage is at a relatively considerable value (far below 1V). In this way, the total time of high potential in the entire purge process is shorter than that of the hydrogen-air synchronous purge method.

[0092] Maintaining the pressure after purging the hydrogen chamber alone helps to improve the utilization rate of hydrogen and reduce the hydrogen consumption caused by the purging process. After a short period of high-flow hydrogen purging, the hydrogen chamber is closed, which shortens the hydrogen purging time compared to simultaneous hydrogen and air purging.

[0093] Based on the same inventive concept, Figure 3 As shown, an embodiment of the present invention further provides a hydrogen-oxygen fuel cell purge control device, comprising:

[0094] The first purge module is used to introduce air into the bypass pipeline to dilute the emission concentration of hydrogen during hydrogen purge; introduce hydrogen into the hydrogen chamber of the fuel cell stack and purge for a target time, and the purged hydrogen is discharged from the exhaust and drain valve;

[0095] A pressure-maintaining module, used for maintaining the pressure of the hydrogen cavity after the hydrogen cavity is purged for a target time;

[0096] The second purge module is used to close the bypass pipeline to allow air to enter the cathode for purge inside the stack;

[0097] The acquisition module is used to obtain the voltage of a single cell in the battery stack and the voltage of the DCDC input terminal;

[0098] The operation module is used to start current loading for the hydrogen and oxygen fuel cell when the voltage of a single cell in the battery stack, the voltage at the DCDC input terminal, and the total purge time meet the operation conditions.

[0099] Optionally, the first purge module is further used for:

[0100] Open the hydrogen inlet valve and the exhaust and drain valve;

[0101] Determine the opening of the hydrogen inlet proportional valve according to the preset hydrogen pressure;

[0102] Set a target duration for hydrogen purge in the fuel cell stack;

[0103] Hydrogen is introduced into the hydrogen chamber of the fuel cell stack, and hydrogen purge is performed for a target time, and the purged hydrogen is discharged from the exhaust and drain valve.

[0104] Optionally, the first purge module is further used for:

[0105] Open the air compressor and bypass line valve;

[0106] Close the air inlet valve and back pressure valve of the air chamber, and introduce air into the bypass line to dilute the emission concentration of hydrogen during hydrogen purging.

[0107] Optionally, the first purge module is further used for:

[0108] Obtain the hydrogen inlet pressure and the average cell voltage of each battery in the stack;

[0109] If the hydrogen inlet pressure and the average cell voltage of each battery in the battery stack meet the discharge conditions, the DCDC is controlled to be in the discharge mode;

[0110] Optionally, the first purge module is further used for:

[0111] If the difference between the hydrogen inlet pressure and the preset target pressure is within the target range, and the average cell voltage of each battery in the battery stack is greater than the voltage threshold, the DCDC is controlled to be in the discharge mode.

[0112] Optionally, the pressure holding module is also used for:

[0113] Close the exhaust and drain valves, keep the hydrogen inlet valve open, and adjust the opening of the hydrogen inlet proportional valve through PID according to the preset target pressure to maintain the required pressure of the hydrogen chamber.

[0114] Optionally, the second purge module is further used for:

[0115] The air compressor is maintained at a preset speed, the air intake valve of the air chamber is opened, the bypass pipeline valve is closed, and the opening of the back pressure valve is adjusted to maintain a constant hydrogen-air pressure difference.

[0116] Optionally, the runtime module is also used to:

[0117] If the lowest voltage among the single-cell voltages in the stack is greater than a first threshold, the DCDC input voltage is greater than a second threshold, and the total purge duration is greater than a duration threshold, the fuel cell starts current loading.

[0118] In summary, the embodiment of this specification provides a hydrogen-oxygen fuel cell purge control device, which dilutes the emission concentration of hydrogen during hydrogen purge by introducing air into the bypass line; introduces hydrogen into the hydrogen chamber of the stack, and purges for a target time, and the purged hydrogen is discharged from the exhaust and drain valve; after the hydrogen chamber is purged for a target time, the hydrogen chamber is pressurized; the bypass line is closed to allow air to enter the cathode for purge in the stack; the voltage of a single cell in the stack and the voltage of the DCDC input terminal are obtained; if the voltage of a single cell in the stack, the voltage of the DCDC input terminal and the total purge time meet the operating conditions, the hydrogen-oxygen fuel cell starts to load current. In this way, the hydrogen-air step-by-step purge strategy can greatly shorten the total duration of the overpotential, and the DCDC discharge mode is used to consume oxygen in the stack and lower the overvoltage while purging hydrogen.

[0119] Based on the same inventive concept, an embodiment of the present invention further provides a hydrogen-oxygen fuel cell. When the stack of the hydrogen-oxygen fuel cell is purged, the aforementioned hydrogen-oxygen fuel cell purging control method is applicable.

[0120] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the hydrogen-oxygen fuel cell stack during purging described above can refer to the corresponding process in the aforementioned method, and will not be described in detail here.

[0121] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the controller of the vehicle described above can refer to the corresponding process in the aforementioned method, and will not be elaborated here.

[0122] The above are only various embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A hydrogen-oxygen fuel cell purge control method, characterized in that: include: Air is introduced into the bypass line to dilute the emission concentration of hydrogen during hydrogen purge; Introduce hydrogen into the hydrogen chamber of the fuel cell stack and purge for a target time, and the purged hydrogen is discharged from the exhaust and drain valve; After the hydrogen cavity is purged for a target time, the hydrogen cavity is pressurized; Close the bypass line to allow air to enter the cathode for purge inside the stack; Obtain the voltage of the single-chip battery in the battery stack and the voltage of the DCDC input terminal; If the voltage of a single cell in the stack, the voltage at the DCDC input terminal, and the total purge time meet the operating conditions, the hydrogen and oxygen fuel cell starts to load the current.

2. The method according to claim 1, characterized in that: The step of introducing hydrogen into the hydrogen chamber of the fuel cell stack and performing a purge for a target time, wherein the purged hydrogen is discharged from an exhaust and drain valve, comprises: Open the hydrogen inlet valve and the exhaust and drain valve; Determine the opening of the hydrogen inlet proportional valve according to the preset hydrogen pressure; Set a target duration for hydrogen purge in the fuel cell stack; Hydrogen is introduced into the hydrogen chamber of the fuel cell stack, and hydrogen purge is performed for a target time, and the purged hydrogen is discharged from the exhaust and drain valve.

3. The method according to claim 1, characterized in that The step of introducing air into the bypass line to dilute the emission concentration of hydrogen during hydrogen purge includes: Open the air compressor and bypass pipeline valve, close the air intake valve and back pressure valve of the air chamber, and introduce air into the bypass pipeline to dilute the emission concentration of hydrogen during hydrogen purging.

4. The method according to claim 1, characterized in that: After the step of introducing hydrogen into the fuel cell stack, performing hydrogen purge for a target time, and discharging the purged hydrogen from the exhaust and drain valve, the method further includes: Obtain the hydrogen inlet pressure and the average cell voltage of each battery in the stack; If the hydrogen inlet pressure and the average cell voltage of each battery in the battery stack meet the discharge conditions, the DCDC is controlled to be in the discharge mode.

5. The method according to claim 4, characterized in that If the hydrogen inlet pressure and the average cell voltage of each battery in the battery stack meet the discharge condition, controlling the DCDC to be in the discharge mode includes: If the difference between the hydrogen inlet pressure and the preset target pressure is within the target range, and the average cell voltage of each battery in the battery stack is greater than the voltage threshold, the DCDC is controlled to be in the discharge mode.

6. The method according to claim 1, characterized in that The step of maintaining the pressure of the hydrogen cavity comprises: Close the exhaust and drain valves, keep the hydrogen inlet valve open, and adjust the opening of the hydrogen inlet proportional valve through PID according to the preset target pressure to maintain the required pressure of the hydrogen chamber.

7. The method according to claim 1, characterized in that The method of closing the bypass pipeline to allow air to enter the cathode for purge in the stack includes: The air compressor is maintained at a preset speed, the air intake valve of the air cavity is opened, the bypass pipeline valve is closed, and the opening of the back pressure valve is adjusted to maintain a constant hydrogen-air pressure difference, so that air enters the cathode for purge in the stack.

8. The method according to claim 1, characterized in that If the voltage of a single cell in the stack, the voltage at the DCDC input terminal, and the total purge time meet the operating conditions, the hydrogen-oxygen fuel cell starts to load current, including: If the lowest voltage among the single-cell voltages in the stack is greater than a first threshold, the DCDC input voltage is greater than a second threshold, and the total purge duration is greater than a duration threshold, the fuel cell starts current loading.

9. A hydrogen-oxygen fuel cell purge control device, characterized in that: include: A first purge module, used to introduce air into the bypass pipeline to dilute the emission concentration of hydrogen during hydrogen purge; Introduce hydrogen into the hydrogen chamber of the fuel cell stack and purge for a target time, and the purged hydrogen is discharged from the exhaust and drain valve; A pressure-maintaining module, used for maintaining the pressure of the hydrogen cavity after the hydrogen cavity is purged for a target time; The second purge module is used to close the bypass pipeline to allow air to enter the cathode for purge inside the stack; The acquisition module is used to obtain the voltage of a single cell in the battery stack and the voltage of the DCDC input terminal; The operation module is used to start current loading for the hydrogen and oxygen fuel cell when the voltage of a single cell in the battery stack, the voltage at the DCDC input terminal, and the total purge time meet the operation conditions.

10. A hydrogen-oxygen fuel cell, characterized in that: When the hydrogen-oxygen fuel cell stack is purged, the hydrogen-oxygen fuel cell purging control method described in any one of claims 1 to 8 is applicable.

Images