Water and nitrogen discharge control system and control method for hydrogen fuel cell

Abstract

The invention provides a water and nitrogen discharging control system and method for a hydrogen fuel cell, the control system comprises a fuel cell system control unit FCU, a water discharging valve, a nitrogen discharging valve and a hydrogen in-pile pressure sensor, the hydrogen in-pile pressure sensor is used for collecting the current hydrogen in-pile pressure and sending the current hydrogen in-pile pressure to the fuel cell system control unit FCU; and the fuel cell system control unit FCU is used for alternately controlling the drain valve and the nitrogen discharge valve to be opened after collecting the current hydrogen in-pile pressure, and controlling the drain valve and the nitrogen discharge valve to be closed when the fluctuation of the current hydrogen in-pile pressure is greater than a threshold value. According to the present invention, the opening of the drain valve and the nitrogen discharge valve is alternately controlled according to the hydrogen in-pile pressure, such that the large hydrogen pressure fluctuation caused by the simultaneous opening of the drain valve and the nitrogen discharge valve is avoided, and the drain valve and the nitrogen discharge valve are controlled to be closed when the hydrogen pressure fluctuation is too large so as to ensure the stability of the fuel cell system.

Description

Technical Field

[0001] The present disclosure relates to the technical field of hydrogen fuel cells, and in particular to a water and nitrogen discharge control system and a control method. Background Art

[0002] Hydrogen fuel cells are power generation devices that directly convert the chemical energy of hydrogen and oxygen into electrical energy. The only product of the reaction is water. Due to their outstanding advantages of zero emissions, no pollution, high efficiency and energy saving, and low noise, hydrogen fuel cell vehicles will definitely become the trend of future new energy vehicle development.

[0003] During the operation of a hydrogen fuel cell, nitrogen and other gas impurities in the air on the cathode side will gradually penetrate into the anode side, diluting the hydrogen concentration on the anode side. When the concentration of nitrogen and other impurity gases reaches a certain ratio, the performance of the hydrogen fuel cell will seriously decline, affecting the normal operation of the system. Therefore, a nitrogen exhaust valve is added to the hydrogen circulation system of the hydrogen fuel cell, and the nitrogen exhaust valve is opened periodically to discharge nitrogen and other gases in the hydrogen system. In addition, the water produced by the cathode of a hydrogen fuel cell under high current will be much greater than the water produced by the anode, and the cathode water will penetrate into the anode. Therefore, a drain valve is required at the anode to discharge excess water in the fuel cell in time to avoid degradation of the hydrogen fuel cell performance due to water blockage. When a hydrogen fuel cell is draining water and nitrogen, the drain valve and the nitrogen exhaust valve may be opened at the same time, which will cause large fluctuations in hydrogen pressure, increase hydrogen consumption, and reduce the efficiency of the hydrogen fuel cell and system stability.

[0004] The present disclosure designs a water discharge and nitrogen discharge control system to control the staggered water discharge and nitrogen discharge time. When the system recognizes that the hydrogen fuel cell is draining water, the nitrogen discharge operation is prohibited; when the hydrogen fuel cell is draining nitrogen, the water discharge operation is prohibited. When the hydrogen pressure fluctuation caused by the system water discharge and nitrogen discharge is large, the water discharge valve and the nitrogen discharge valve are closed to effectively control the hydrogen circuit pressure fluctuation, reduce hydrogen consumption, and improve the operating stability of the hydrogen fuel cell system. Summary of the invention

[0005] A technical problem to be solved by the present disclosure is that when a hydrogen fuel cell is discharging water and nitrogen, if the water discharge valve and the nitrogen discharge valve are opened at the same time, it will cause a large fluctuation in hydrogen pressure, thereby reducing the system stability of the hydrogen fuel cell.

[0006] In order to solve the above technical problems, the first aspect of the embodiment of the present disclosure provides a hydrogen fuel cell water and nitrogen discharge control system. The control system includes: a fuel cell system control unit FCU, a water discharge valve, a nitrogen discharge valve and a hydrogen inlet pressure sensor, wherein the hydrogen inlet pressure sensor is used to collect the current hydrogen inlet pressure and send it to the fuel cell system control unit FCU; the fuel cell system control unit FCU is used to alternately control the water discharge valve and the nitrogen discharge valve to open after collecting the current hydrogen inlet pressure, and control the water discharge valve and the nitrogen discharge valve to close when the fluctuation of the current hydrogen inlet pressure is greater than the threshold.

[0007] In some embodiments, the fuel cell system control unit FCU is used to start timing after it is detected that the current hydrogen inlet pressure reaches a preset value, and to alternately control the drain valve and the nitrogen exhaust valve to open after the timing reaches a predetermined time.

[0008] In some embodiments, alternately controlling the opening of the drain valve and the nitrogen exhaust valve includes: opening the drain valve, and controlling the drain valve to close when the opening time of the drain valve exceeds a threshold or the target hydrogen inlet pressure is greater than the current hydrogen inlet pressure by more than a threshold; and opening the nitrogen exhaust valve, and controlling the nitrogen exhaust valve to close when the opening time of the nitrogen exhaust valve exceeds a threshold or the target hydrogen inlet pressure is greater than the current hydrogen inlet pressure by more than a threshold.

[0009] In some embodiments, a predetermined period of time is waited before opening the nitrogen exhaust valve.

[0010] In some embodiments, the system further includes a vehicle control unit VCU, which is used to send startup and shutdown instructions to the fuel cell system control unit FCU.

[0011] A second aspect of an embodiment of the present disclosure provides a water and nitrogen discharge control method for a hydrogen fuel cell, wherein the hydrogen fuel cell comprises a water drain valve, a nitrogen discharge valve and a hydrogen inlet stack pressure sensor, and the method comprises: collecting the current hydrogen inlet stack pressure; and after collecting that the current hydrogen inlet stack pressure reaches a preset value, alternately controlling the water drain valve and the nitrogen discharge valve to open, and when the fluctuation of the current hydrogen inlet stack pressure is greater than a threshold value, controlling the water drain valve and the nitrogen discharge valve to close.

[0012] In some embodiments, after it is collected that the current hydrogen inlet pressure reaches a preset value, the timing is started, and after the timing reaches a predetermined time, the water discharge valve and the nitrogen discharge valve are alternately controlled to open.

[0013] In some embodiments, alternately controlling the opening of the drain valve and the nitrogen exhaust valve includes: opening the drain valve, and controlling the drain valve to close when the opening time of the drain valve exceeds a threshold or the target hydrogen inlet pressure is greater than the current hydrogen inlet pressure by more than a threshold; and opening the nitrogen exhaust valve, and controlling the nitrogen exhaust valve to close when the opening time of the nitrogen exhaust valve exceeds a threshold or the target hydrogen inlet pressure is greater than the current hydrogen inlet pressure by more than a threshold.

[0014] In some embodiments, a predetermined period of time is waited before opening the nitrogen exhaust valve.

[0015] In some embodiments, the control method is executed in a loop before a shutdown instruction is received.

[0016] Through the above technical scheme, the hydrogen fuel cell water and nitrogen exhaust control system and control method provided by the present invention alternately controls the opening of the water drain valve and the nitrogen exhaust valve according to the collected pressure signal of the hydrogen entering the stack, thereby avoiding large hydrogen pressure fluctuations caused by the simultaneous opening of the water drain valve and the nitrogen exhaust valve, and when the fluctuation of the pressure signal of the hydrogen entering the stack is greater than the threshold value, the water drain valve and the nitrogen exhaust valve are controlled to be closed, thereby ensuring the stability of the hydrogen pressure of the fuel cell system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 It is a schematic diagram of the structure of the drainage and nitrogen removal control system disclosed in the embodiment of the present disclosure;

[0019] Figure 2 It is a flow chart of the drainage and nitrogen discharge control method disclosed in the embodiment of the present disclosure.

[0020] Description of reference numerals:

[0021] 1. Fuel cell system control unit FCU; 2. Vehicle control unit VCU; 3. Hydrogen inlet pressure sensor; 4. Drain valve; 5. Nitrogen exhaust valve. DETAILED DESCRIPTION

[0022] The following is a further detailed description of the embodiments of the present disclosure in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present disclosure, but cannot be used to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

[0023] The present disclosure provides these embodiments to make the present disclosure thorough and complete, and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary, and not as limiting.

[0024] It should be noted that, in the description of the present disclosure, unless otherwise specified, the meaning of "multiple" is greater than or equal to two; the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating the orientation or positional relationship, are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present disclosure. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0025] In addition, the words "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. "Vertical" does not mean vertical in the strict sense, but is within the tolerance range. "Parallel" does not mean parallel in the strict sense, but is within the tolerance range. "Include" or "comprising" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements.

[0026] It should also be noted that in the description of the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances. When a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

[0027] All terms used in the present disclosure have the same meanings as those understood by those of ordinary skill in the art to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, for example, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined as such herein.

[0028] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0029] Example

[0030] Figure 1 Schematic diagram of the structure of the drainage and nitrogen removal control system disclosed in the embodiment of the present disclosure. Figure 1As shown, the control system includes: a fuel cell system control unit FCU1, a water drain valve 4, a nitrogen exhaust valve 5 and a hydrogen inlet pressure sensor 3, wherein the hydrogen inlet pressure sensor 3 is used to collect the current hydrogen inlet pressure and send it to the fuel cell system control unit FCU1; the fuel cell system control unit FCU1 is used to alternately control the water drain valve 4 and the nitrogen exhaust valve 5 to open after receiving the current hydrogen inlet pressure, and control the water drain valve 4 and the nitrogen exhaust valve 5 to close when the fluctuation of the current hydrogen inlet pressure is greater than a threshold value.

[0031] The present disclosure collects the current hydrogen inlet pressure, and controls the opening of the drain valve 4 and the nitrogen exhaust valve 5 alternately according to the current hydrogen pressure, so as to avoid excessive fluctuations in the hydrogen pressure in the fuel cell caused by the simultaneous opening of the drain valve 4 and the nitrogen exhaust valve 5, and can reduce the loss of hydrogen, thereby improving the efficiency of the fuel cell and the system stability. When the fluctuation of the hydrogen inlet pressure is too large and greater than the set threshold, it may cause uneven gas distribution inside the battery, thereby affecting the reaction process of the fuel cell. At this time, it is necessary to close the drain valve 4 and the nitrogen exhaust valve 5 to reduce the impact on the fuel cell, which helps to maintain the stable performance of the fuel cell system and prevent the battery performance from decaying too quickly. It can be understood that the threshold of the pressure fluctuation is determined according to the performance of the battery stack itself when it leaves the factory, and the threshold is set within the pressure difference range that the battery stack can withstand to ensure that the battery stack is not damaged.

[0032] In some embodiments, the fuel cell system control unit FCU1 is used to start timing after collecting that the current hydrogen inlet pressure reaches a preset value, and after the timing reaches a predetermined time, alternately control the drain valve 4 and the nitrogen exhaust valve 5 to open.

[0033] In some embodiments, alternately controlling the opening of the drain valve 4 and the nitrogen exhaust valve 5 includes: opening the drain valve 4, and controlling the drain valve 4 to close when the opening time of the drain valve 4 exceeds a threshold or the target hydrogen inlet pressure is greater than the current hydrogen inlet pressure by more than a threshold; and opening the nitrogen exhaust valve 5, and controlling the nitrogen exhaust valve 5 to close when the opening time of the nitrogen exhaust valve 5 exceeds a threshold or the target hydrogen inlet pressure is greater than the current hydrogen inlet pressure by more than a threshold.

[0034] Specifically, the time threshold for judging whether the drain valve 4 and the nitrogen exhaust valve 5 are closed is set by the power supply current during the operation of the battery stack. Under different working conditions, the size of the time threshold is different. Those skilled in the art can set the time threshold accordingly according to different application scenarios and different characteristics of the battery stack itself. And by setting the time threshold, the opening time of the drain valve 4 and the nitrogen exhaust valve 5 can be accurately controlled, so as to achieve accurate management of the drainage and nitrogen exhaust processes, which helps to ensure that the drainage and nitrogen exhaust processes achieve the best effect, and avoid the opening time being too short, resulting in incomplete drainage and nitrogen exhaust, or the opening time being too long, resulting in excessive gas pressure difference.

[0035] In some embodiments, a preset time period is waited before opening the nitrogen exhaust valve 5 .

[0036] Specifically, by waiting for a preset period of time before opening the nitrogen exhaust valve 5, it is ensured that the drainage process controlled by the drain valve 4 has been completed, that is, the water in the fuel cell system has been fully discharged, thereby avoiding residual water. During the drainage process, the pressure of the fuel cell system may change. Waiting for a period of time before closing the drain valve 4 and opening the nitrogen exhaust valve 5 can allow the system pressure to gradually stabilize, which helps to ensure that when the nitrogen exhaust valve 5 is opened, the system pressure will not suddenly drop or rise, thereby protecting the stability and reliability of the fuel cell system. And by setting this waiting time, it can be ensured that the drain valve 4 and the nitrogen exhaust valve 5 will not be opened at the same time, so as to achieve the alternating opening of the drain valve 4 and the nitrogen exhaust valve 5.

[0037] In some embodiments, the system further includes a vehicle control unit VCU2 for sending startup and shutdown instructions to the fuel cell system control unit FCU1.

[0038] Specifically, when the vehicle control unit VCU2 sends a power-on command to the fuel cell system control unit FCU1, it is used to control the power-on of the control system. When the control system is powered on, the drain valve 4 and the nitrogen exhaust valve 5 are in a controllable state, waiting to receive the control command from the fuel cell system control unit FCU1. When the shutdown command is received, the entire control system is shut down, and the drain valve 4 and the nitrogen exhaust valve 5 are in a completely closed state, and no longer receive the control of the control command.

[0039] The disclosed embodiment provides a method for controlling water and nitrogen discharge for a hydrogen fuel cell. The hydrogen fuel cell comprises a water discharge valve 4, a nitrogen discharge valve 5 and a hydrogen inlet pressure sensor 3. The method comprises: collecting the current hydrogen inlet pressure; and after collecting that the current hydrogen inlet pressure reaches a preset value, alternately controlling the water discharge valve 4 and the nitrogen discharge valve 5 to open, and when the fluctuation of the current hydrogen inlet pressure is greater than a threshold value, controlling the water discharge valve 4 and the nitrogen discharge valve 5 to close.

[0040] In some embodiments, after it is collected that the current hydrogen inlet pressure reaches a preset value, the timing is started, and after the timing reaches a predetermined time, the water discharge valve 4 and the nitrogen discharge valve 5 are alternately controlled to open.

[0041] In some embodiments, alternately controlling the opening of the drain valve 4 and the nitrogen exhaust valve 5 includes: opening the drain valve 4, and controlling the drain valve 4 to close when the opening time of the drain valve 4 exceeds a threshold or the target hydrogen inlet pressure is greater than the current hydrogen inlet pressure by more than a threshold; and opening the nitrogen exhaust valve 5, and controlling the nitrogen exhaust valve 5 to close when the opening time of the nitrogen exhaust valve 5 exceeds a threshold or the target hydrogen inlet pressure is greater than the current hydrogen inlet pressure by more than a threshold.

[0042] In some embodiments, a preset time period is waited before opening the nitrogen exhaust valve 5 .

[0043] In some embodiments, the control method is executed in a loop before a shutdown instruction is received.

[0044] Figure 2 Flow chart of the drainage and nitrogen discharge control method disclosed in the embodiment of the present disclosure. Figure 2 As shown, the process of the water discharge and nitrogen discharge control method disclosed in the embodiment of the present disclosure is explained.

[0045] Step 1: Connect low voltage to the system;

[0046] Step 2: The vehicle control unit VCU sends a power-on command to the fuel cell system control unit FCU;

[0047] Step 3: When the current hydrogen inlet pressure collected by the fuel cell system control unit FCU1 reaches a preset value, the timing starts;

[0048] Step 4: If the timing of the fuel cell system control unit FCU1 exceeds 2S, go to step 5, otherwise go to step 3;

[0049] Step 5: The fuel cell system control unit FCU1 controls the drain valve 4 to open;

[0050] Step 6: Determine whether the target hydrogen inlet pressure is greater than the current hydrogen inlet pressure by more than 7 kPa. If yes, proceed to step 8; otherwise, proceed to step 7.

[0051] Step 7: Determine whether the opening time of the drain valve 4 exceeds 0.5S, if yes, go to step 8, otherwise go to step 5;

[0052] Step 8: The fuel cell system control unit FCU1 controls the drain valve 4 to be closed;

[0053] Step 9: The fuel cell system control unit FCU1 starts timing;

[0054] Step 10: Determine whether the closing time of the drain valve 4 exceeds 0.2S, if yes, go to step 11, otherwise go to step 9;

[0055] Step 11: The fuel cell system control unit FCU1 controls the nitrogen exhaust valve 5 to open;

[0056] Step 12: Determine whether the target hydrogen inlet pressure is greater than the current hydrogen inlet pressure by more than 7 kPa. If yes, proceed to step 14; otherwise, proceed to step 13.

[0057] Step 13: Determine whether the opening time of the nitrogen exhaust valve 5 exceeds 0.5S, if yes, proceed to step 14, otherwise proceed to step 11;

[0058] Step 14: The fuel cell system control unit FCU1 controls the nitrogen exhaust valve 5 to be closed, and the process goes to step 15;

[0059] Step 15: Determine whether the vehicle control unit VCU2 sends a shutdown command to the fuel cell system control unit FCU1, if yes, proceed to step 17, otherwise proceed to step 16;

[0060] Step 16: Go to step 4;

[0061] Step 17: Shut down the system.

[0062] It is understandable that the time threshold and pressure threshold set in the above steps are only for illustrative purposes and are not limiting. Those skilled in the art may set different values ​​according to actual needs.

[0063] So far, various embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0064] Although some specific embodiments of the present disclosure have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present disclosure. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict.

Claims

1. A hydrogen fuel cell water and nitrogen discharge control system, characterized in that: The control system comprises: a fuel cell system control unit FCU (1), a water discharge valve (4), a nitrogen discharge valve (5) and a hydrogen inlet pressure sensor (3). The hydrogen inlet pressure sensor (3) is used to collect the current hydrogen inlet pressure and send it to the fuel cell system control unit FCU (1); The fuel cell system control unit FCU (1) is used to alternately control the water drain valve (4) and the nitrogen exhaust valve (5) to open after collecting the current hydrogen inlet pressure, and to control the water drain valve (4) and the nitrogen exhaust valve (5) to close when the fluctuation of the current hydrogen inlet pressure is greater than a threshold.

2. The control system according to claim 1, characterized in that: The fuel cell system control unit FCU (1) is used to start timing after collecting that the current hydrogen inlet pressure reaches a preset value, and after the timing reaches a predetermined time, alternately control the water discharge valve (4) and the nitrogen discharge valve (5) to open.

3. The control system according to claim 1 or 2, characterized in that: Alternatingly controlling the water discharge valve (4) and the nitrogen discharge valve (5) to open comprises: Opening the drain valve (4), and controlling the drain valve (4) to close when the opening time of the drain valve (4) exceeds a threshold or the target hydrogen inlet pressure is greater than the current hydrogen inlet pressure by more than a threshold; and The nitrogen exhaust valve (5) is opened, and when the opening time of the nitrogen exhaust valve (5) exceeds a threshold value or the target hydrogen inlet pressure is greater than the current hydrogen inlet pressure by more than a threshold value, the nitrogen exhaust valve (5) is controlled to be closed.

4. The control system according to claim 3, characterized in that: Before opening the nitrogen exhaust valve (5), wait for a preset period of time.

5. The control system according to claim 1, characterized in that The system also includes a vehicle control unit VCU (2) for sending startup and shutdown instructions to the fuel cell system control unit FCU (1).

6. A method for controlling water and nitrogen discharge for a hydrogen fuel cell, characterized in that: The hydrogen fuel cell comprises a water discharge valve (4), a nitrogen discharge valve (5) and a hydrogen inlet pressure sensor (3), and the method comprises: Collect the current hydrogen inlet pressure; and After it is collected that the current hydrogen inlet pressure reaches a preset value, the water drain valve (4) and the nitrogen exhaust valve (5) are alternately controlled to be opened, and when the fluctuation of the current hydrogen inlet pressure is greater than a threshold value, the water drain valve (4) and the nitrogen exhaust valve (5) are controlled to be closed.

7. The control method according to claim 6, characterized in that: After the current hydrogen inlet pressure reaches a preset value, the timing is started, and after the timing reaches a predetermined time, the water discharge valve (4) and the nitrogen discharge valve (5) are alternately controlled to open.

8. The control method according to claim 6 or 7, characterized in that: Alternatingly controlling the water discharge valve (4) and the nitrogen discharge valve (5) to open comprises: Opening the drain valve (4), and controlling the drain valve (4) to close when the opening time of the drain valve (4) exceeds a threshold or the target hydrogen inlet pressure is greater than the current hydrogen inlet pressure by more than a threshold; and The nitrogen exhaust valve (5) is opened, and when the opening time of the nitrogen exhaust valve (5) exceeds a threshold value or the target hydrogen inlet pressure is greater than the current hydrogen inlet pressure by more than a threshold value, the nitrogen exhaust valve (5) is controlled to be closed.

9. The control method according to claim 8, characterized in that: Before opening the nitrogen exhaust valve (5), wait for a preset period of time.

10. The control method according to claim 7, characterized in that: Before receiving a shutdown command, the control method is executed in a loop.

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