Fuel cell anode drainage method

Abstract

This invention discloses a method for draining the anode of a fuel cell, relating to the field of fuel cell technology. The method includes the following steps: setting the calibrated closing time of the drain valve to T. off The calibrated drainage start time is T. wtr The calibrated exhaust opening time is T N2 The total opening time of the drain valve is T. wtr +T N2 The operating cycle of the drain valve is T. off +T wtr +T N2 During the operating cycle of the drain valve, when the drain valve opens, the gas pressure change is monitored. The actual drainage time T is the time from when the drain valve opens until the gas pressure begins to drop. wtr‑act By comparing the actual drainage time T wtr‑act With the calibrated opening and drainage time T wtr The operating cycle and / or drainage volume of the drain valve can be dynamically adjusted based on monitoring data, resulting in more accurate drainage and preventing membrane drying or flooding.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and more particularly to a method for draining fuel cell anodes. Background Technology

[0002] During fuel cell operation, water is generated at the cathode. Due to the concentration gradient, water permeates from the cathode to the anode, covering the membrane electrode assembly (MEA). Once the water reaches a certain level, it hinders hydrogen diffusion to the MEA, reducing hydrogen levels and potentially causing reverse polarity, resulting in irreversible damage to the MEA and bipolar plates. Therefore, hydrogen recirculation systems typically include hydrogen circulation devices and gas-liquid separators. Hydrogen carries water from the fuel cell stack to the gas-liquid separator, where it is separated and accumulated. A drain valve periodically opens to discharge the accumulated liquid water. However, the water transport process at the MEA is affected by drag effects, concentration gradients, and the physical properties of the membrane, making it difficult to accurately model and predict the actual amount of water accumulated at the anode. Furthermore, the actual amount of liquid water separated from the anode to the gas-liquid separator is also difficult to predict under different hydrogen flow rates, pipeline structures, and temperatures.

[0003] Current technologies use calibration methods to set the drainage cycle and time, but these methods are still susceptible to inaccurate drainage due to factors such as real-time operating conditions, membrane electrode state, and ambient temperature. Long drainage cycles and short drainage times can lead to anode water accumulation, affecting hydrogen diffusion and causing starvation and reverse polarity. Conversely, short drainage cycles and long drainage times can cause pressure fluctuations, increased control difficulty, and reduced hydrogen utilization. Therefore, accurately setting the drainage cycle and drainage volume to precisely discharge anode water from the system without wasting excessive hydrogen is crucial for fuel cells. Summary of the Invention

[0004] The purpose of this invention is to provide a method for draining the anode of a fuel cell, which can accurately set the draining cycle and drainage volume of the fuel cell anode to avoid membrane drying or flooding.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A fuel cell anode drainage method includes the following steps:

[0007] Set the calibrated closing time of the drain valve to T. off The calibrated opening time for drainage is T. wtr The calibrated exhaust opening time is T N2 The total opening time of the drain valve is T. wtr +T N2 The operating cycle of the drain valve is T. off +T wtr +T N2 ;

[0008] During the operating cycle, when the drain valve opens, the gas pressure change is monitored, and the actual drainage time T is the time from when the drain valve opens until the gas pressure begins to decrease. wtr-act ;

[0009] By comparing the actual drainage time T wtr-act With the calibrated opening drainage time T wtr The operating cycle and / or drainage volume of the drain valve can be dynamically adjusted.

[0010] As an alternative method for draining the anode of a fuel cell, the calibrated opening and draining time T of the drain valve in the next operating cycle is adjusted. wtr Adjust the operating cycle of the drain valve.

[0011] As an alternative method for draining the anode of a fuel cell, the calibrated opening time T of the drain valve in the next operating cycle is... wtr The adjustment method for ˊ includes the following steps:

[0012] Determine the actual drainage time T wtr-act With the calibrated opening drainage time T wtr Are they the same?

[0013] If the actual drainage time T wtr-act With the calibrated opening drainage time T wtr If they are different, then the calibrated start-up drainage time T in the next operating cycle will be different. wtr ˊ equals the actual drainage time T during the previous operating cycle. wtr-act .

[0014] As an alternative to the fuel cell anode drainage method, the fuel cell anode drainage method further includes the following steps:

[0015] During the operating cycle of the drain valve, when the drain valve is open, while monitoring the change in gas pressure, the current pressure difference ΔP before and after the drain valve is detected, and the current drainage flow rate Q is calculated based on the flow guiding capacity Kv of the drain valve and the current pressure difference ΔP before and after the drain valve.

[0016] Based on the actual drainage time T wtr-act The actual drainage volume M is calculated from the current drainage flow rate Q. act ;

[0017] Set the preset water storage capacity M of the gas-water separator set According to the preset water storage capacity M set and the actual drainage volume M act Adjust the drainage volume of the drain valve in the next operating cycle.

[0018] As an alternative method for draining water from the anode of a fuel cell, the current drainage flow rate Q is calculated using the following formula:

[0019] Q = Kv / (ρ / (1000△P)) 0.5 ,

[0020] Where: ρ is the density of water.

[0021] As an alternative method for draining fuel cell anodes, the actual drainage volume M act The calculation formula is: M act =T wtr-act ×Q.

[0022] As an alternative method for draining the anode of a fuel cell, the calibrated closing time T of the drain valve in the next operating cycle is adjusted. off Adjust the drainage volume of the drain valve in the next operating cycle.

[0023] As an alternative method for draining the anode of a fuel cell, the calibrated closing time T of the drain valve in the next operating cycle off The adjustment method for ˊ includes the following steps:

[0024] Based on the actual drainage volume M act With the preset water storage capacity M set The difference is used to calculate the adjustment value for the closing time of the drain valve;

[0025] Calculate the calibrated closing time T of the drain valve in the next operating cycle based on the adjustment value of the drain valve's closing time. off ˊ, the calibrated closing time T of the drain valve in the next operating cycle off ˊ is equal to the calibrated shutdown time T in the previous operating cycle. off The sum of the adjustment value of the closing time of the drain valve.

[0026] As an alternative method for draining fuel cell anodes, the adjustment value of the closing time of the drain valve is equal to the actual drainage volume M. act With the preset water storage capacity M set The difference is divided by the actual water accumulation rate F of the gas-water separator.

[0027] As an alternative method for draining fuel cell anodes, the actual water accumulation rate F of the gas-water separator is equal to the actual drainage volume M. act Divide by the calibrated closing time T off .

[0028] The beneficial effects of this invention are:

[0029] The anode drainage method for fuel cells provided by this invention sets the calibrated closing time of the drainage valve to T. off The calibrated opening time for drainage is T. wtr The calibrated exhaust opening time is T N2 The operating cycle of the drain valve is T. off +T wtr +T N2 During the operating cycle of the drain valve, gas pressure changes are monitored. The actual drainage time T is the time from when the drain valve opens until a decrease in gas pressure is detected. wtr-act By comparing the actual drainage time T wtr-act The calibrated opening time for drainage is T wtr The operating cycle and / or drainage volume of the drain valve are dynamically adjusted. The anode drainage method for this fuel cell determines the water state (whether the water is completely drained or not) based on the gas pressure change cycle, thus determining the actual drainage time T. wtr-act Then, by comparing the actual drainage time T... wtr-act With the calibrated opening and drainage time T wtr The operating cycle and / or drainage volume of the drain valve are dynamically adjusted to ensure that the water at the fuel cell anode is completely drained within the next operating cycle of the drain valve, while maintaining stable battery voltage. Real-time monitoring is implemented, and the operating cycle and / or drainage volume of the drain valve are dynamically adjusted based on the monitoring results to prevent membrane drying or flooding. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the drainage structure of the fuel cell system provided by the present invention;

[0031] Figure 2 This is a schematic diagram of the gas pressure change under ideal conditions when the anode of a fuel cell is drained, as provided by the present invention.

[0032] Figure 3 This is a schematic diagram of gas pressure changes when the actual drainage time is short during fuel cell anode drainage provided by the present invention.

[0033] Figure 4 This is a flowchart of the fuel cell anode drainage method provided in Embodiment 1 of the present invention;

[0034] Figure 5 This is a flowchart of the method for adjusting the calibrated opening and drainage time of the drain valve in the next operating cycle, as provided in Embodiment 1 of the present invention.

[0035] Figure 6 This is a flowchart of the fuel cell anode drainage method provided in Embodiment 2 of the present invention;

[0036] Figure 7This is a flowchart of the method for adjusting the calibrated closing time of the drain valve in the next operating cycle provided in Embodiment 2 of the present invention;

[0037] Figure 8 This is a comparison chart of the set value, actual value (water drained) and adjusted value of the drain valve in one of the fuel cell anode drainage methods provided in Embodiment 2 of the present invention.

[0038] In the picture:

[0039] 1. Fuel cell stack; 2. Proportional valve; 3. Hydrogen circulation pump; 4. Gas-liquid separator; 5. Drain valve; 6. Inlet pressure sensor; 7. Outlet pressure sensor. Detailed Implementation

[0040] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0041] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions.

[0042] Unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and connections within two components or interactions between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0043] Unless otherwise expressly specified and limited, "above" or "below" a second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of a second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" of a second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0045] like Figure 1 As shown, during operation, the fuel cell system requires hydrogen to be supplied to the stack 1. The flow rate of hydrogen entering the stack 1 is controlled by the proportional valve 2 in the hydrogen pipeline. The hydrogen undergoes an electrochemical reaction within the stack 1, generating electricity and water. A small portion of unreacted hydrogen and water is discharged from the stack 1 and separated by a gas-water separator 4. The separated hydrogen is then recycled back into the stack 1 through the hydrogen circulation pump 3 via the inlet. Water is stored in a reservoir within the gas-water separator 4. A drain valve 5 controls the discharge of water separated by the gas-water separator 4. The drain valve 5 opens periodically to drain accumulated water from the system. Once the water is drained, gas is discharged from the system via the drain valve 5.

[0046] An intake pressure sensor 6 is installed at the intake port of fuel cell stack 1 to detect the intake pressure of fuel cell stack 1. An exhaust pressure sensor 7 is installed at the exhaust port of fuel cell stack 1 to detect the exhaust pressure of fuel cell stack 1.

[0047] Because of the significant differences in density and flow rate between water and gas, the volume of water discharged from the fuel cell system is small, and its impact on the hydrogen pipeline pressure is negligible. However, when gas is discharged from the system through the drain valve, due to the lower density and higher flow rate of the gas, the exhaust will significantly affect the hydrogen pipeline, causing a noticeable drop in the hydrogen pipeline pressure.

[0048] The opening and closing cycle of the drain valve is divided into three time periods: drain valve closing time, drain valve opening and draining time, and vent valve opening and venting time. The total opening time of the drain valve is the sum of the drain valve opening and draining time and the vent valve opening and venting time. The operating cycle of the drain valve is the sum of the drain valve closing time, the drain valve opening and draining time, and the vent valve opening and venting time.

[0049] Set the calibrated closing time of the drain valve to T. off The calibrated opening time for drainage is T.wtr The calibrated exhaust opening time is T N2 The total opening time of the drain valve is T. wtr +T N2 The operating cycle of the drain valve is T. off +T wtr +T N2 .

[0050] Based on the calibrated values ​​of the drain valve during its operating cycle, the hydrogen pressure changes as follows when the fuel cell system is operating under ideal conditions: Figure 2 As shown. However, in actual operation, fuel cell systems are affected by factors such as membrane condition, hydrogen pipeline structure, and operating conditions, resulting in actual drainage times that may differ from theoretical times. For example... Figure 3 and Figure 8 As shown, within the operating cycle of drain valve 5, when the drain valve closing time, drain valve opening time, and vent valve opening time are all set values, the operating cycle of the drain valve is T. off +T wtr +T N2 If the actual drainage time T wtr-act Too short a time will lead to a longer exhaust time, resulting in a prolonged drop in gas pressure (e.g., Figure 3 As shown), this causes pressure fluctuations, affecting battery voltage. If the actual drainage time T... wtr-act Excessive (not shown in the figure), actual drainage time T wtr-act The gas pressure will not decrease during the venting time. By the time the total opening time of drain valve 5 ends, the water will not be completely drained, which may cause flooding of the fuel cell stack or damage to the hydrogen circulation pump.

[0051] Example 1:

[0052] To address the problem in the existing technology that the drain valve 5 drains water according to various parameters calibrated within the operating cycle, but cannot accurately control the drainage cycle and drainage volume due to the influence of real-time operating conditions, membrane electrode status, ambient temperature, etc.

[0053] This embodiment provides a fuel cell anode drainage method, which adds a feedback adjustment strategy to the existing calibration method.

[0054] like Figure 4 As shown, the fuel cell anode exhaust method provided in this embodiment includes the following steps:

[0055] S10. Set the calibrated closing time of drain valve 5 to T. off The calibrated opening time for drainage is T. wtr The calibrated exhaust opening time is T N2 Then the total opening time of drain valve 5 is T. wtr +TN2 The operating cycle of drain valve 5 is T. off +T wtr +T N2 .

[0056] During the operation of the fuel cell system, drain valve 5 first runs for one cycle according to the calibrated parameters. During this cycle, the closing time of drain valve 5 is T. off During the closing time of drain valve 5, the gas-water separator separates the hydrogen and water discharged from the fuel cell stack. The separated hydrogen is then recycled back into the fuel cell stack through the outlet of the gas-water separator by the hydrogen circulation pump, while the separated water is stored in the liquid storage box. When drain valve 5 is opened, the water stored in the liquid storage box begins to drain. After the water is drained, the gas will be discharged through drain valve 5.

[0057] S20. During the operating cycle, when drain valve 5 is opened, the gas pressure change is monitored. The time from when drain valve 5 opens until the gas pressure begins to drop is the actual drainage time T. wtr-act .

[0058] During the period when drain valve 5 is closed, water accumulates in the storage tank, and the gas pressure in the hydrogen pipeline does not change significantly. When drain valve 5 is opened, water is drained first and then gas is released. During drainage, due to the higher density and lower flow rate of water, the discharged volume is small, and its impact on the pressure in the hydrogen pipeline is negligible. Therefore, the gas pressure in the hydrogen pipeline does not change significantly. When all the water has been drained, due to the lower density and higher flow rate of gas, the pressure values ​​detected by the inlet pressure sensor 6 and the outlet pressure sensor 7 will both show a significant decrease. The time from when drain valve 5 opens to when the gas pressure begins to decrease is recorded as the actual drainage time T. wtr-act If the pressure values ​​detected by both the intake pressure sensor 6 and the exhaust pressure sensor 7 do not show a significant decrease, it indicates that the water has not been completely drained.

[0059] S30, By comparing the actual drainage time T wtr-act With the calibrated opening and drainage time T wtr The operating cycle and / or drainage volume of drain valve 5 are dynamically adjusted.

[0060] There are two ways to adjust the operating cycle of drain valve 5: one is based on the actual drainage time T. wtr-act Adjust the operating cycle of drain valve 5. Since the closing time of drain valve 5 is the time it takes for the fuel cell reactor to generate water, under the condition that other factors remain unchanged, the longer the closing time of drain valve 5 is, the more water is generated, and thus the more water needs to be discharged. Therefore, another approach is to adjust the closing time of drain valve 5 according to the actual drainage volume, thereby adjusting the operating cycle of drain valve 5.

[0061] The closing time of drain valve 5 is related to the actual drainage volume, and will be detailed in Example 2. In this example, it is mainly based on the actual drainage time T. wtr-act Adjust the calibrated opening and drainage time in the next operating cycle to adjust the operating cycle of drain valve 5.

[0062] Specifically, such as Figure 5 As shown, the method for adjusting the opening and drainage time of drain valve 5 in the next operating cycle includes the following steps:

[0063] S31. Determine the actual drainage time T wtr-act With the calibrated opening and drainage time T wtr Are they the same? If the actual drainage time T wtr-act With the calibrated opening and drainage time T wtr If the actual drainage time T is the same, the calibrated start-up drainage time in the next operating cycle will remain unchanged; if the actual drainage time T wtr-act With the calibrated opening and drainage time T wtr If they are different, then execute S32.

[0064] S32, Calibrated drainage start time T in the next operating cycle wtr ˊ equals the actual drainage time T in the previous operating cycle. wtr-act .

[0065] In this embodiment, the calibrated opening and drainage time T of the drain valve 5 in the next operating cycle is adjusted. wtr This ensures that the drain valve 5 opens for drainage for the specified time T during the next operating cycle. wtr The internal structure can drain all water without causing a prolonged drop in exhaust pressure, which could lead to pressure fluctuations and affect battery voltage.

[0066] If the actual drainage time T wtr-act Not equal to the rated start-up drainage time T wtr Then the calibration start drainage time T for the next operating cycle will be set. wtr Adjusted to the actual drainage time T within the previous operating cycle. wtr-act The calibrated closing time and calibrated opening venting time remain unchanged. If the actual drainage time T wtr-act Greater than the rated opening drainage time T wtr If so, the operating cycle of drain valve 5 will be extended. If the actual drainage time T wtr-act Less than the rated opening drainage time T wtr This shortens the operating cycle of drain valve 5.

[0067] Example 2:

[0068] The fuel cell anode drainage method provided in this embodiment dynamically adjusts the drainage volume, enabling the fuel cell system to drain all water within the opening time of the drainage valve 5 in the next operating cycle of the drainage valve 5, while ensuring stable battery voltage.

[0069] By controlling the closing time of drain valve 5, the amount of water generated by the fuel cell stack during the closing time of drain valve 5 can be controlled. Under otherwise constant conditions, the longer the closing time of drain valve 5, the more water is generated by the fuel cell stack, and the greater the drainage volume; conversely, the shorter the closing time of drain valve 5, the less water is generated by the fuel cell stack, and the less drainage volume. Based on the actual drainage volume of the previous operating cycle, the closing time of drain valve 5 is adjusted. Changes in the closing time of drain valve 5 result in changes in the operating cycle, meaning both the operating cycle and the drainage volume of drain valve 5 are adjusted simultaneously.

[0070] like Figure 6 As shown, the fuel cell anode drainage method provided in this embodiment further includes the following steps after step S20 of the fuel cell anode drainage method provided in Embodiment 1:

[0071] S30ˊ During the operating cycle of drain valve 5, when drain valve 5 is open, while monitoring the change in gas pressure, the current pressure difference ΔP before and after drain valve 5 is detected. The current drainage flow rate Q is calculated based on the flow-guiding capacity Kv of drain valve 5 and the current pressure difference ΔP before and after drain valve 5.

[0072] Specifically, the formula for calculating the current drainage flow rate Q is: Q=Kv / (ρ / (1000△P)) 0.5 , where ρ is the density of water.

[0073] The flow capacity Kv of drain valve 5 is a parameter of drain valve 5, which can be obtained from the instruction manual of the drain valve 5. The unit of flow capacity Kv is meters. 3 / h, the current drainage flow rate Q is in meters per second (m³). 3 / h, the density ρ of water is 1000kg / m³ 3 The unit of the current pressure difference ΔP before and after drain valve 5 is bar. The current pressure difference ΔP before and after drain valve 5 is equal to the pressure before drain valve 5 minus the pressure after drain valve 5. The pressure before drain valve 5 is equal to the pressure value measured by the outlet pressure sensor 7, and the pressure after drain valve 5 is equal to atmospheric pressure.

[0074] S40, Based on the actual drainage time T wtr-act Calculate the actual drainage volume M based on the current drainage flow rate Q. act .

[0075] Actual drainage M act The calculation formula is: M act =T wtr-act×Q. Based on the calculated current drainage flow rate Q and the actual drainage time T obtained in step S20. wtr-act The actual discharge M is calculated by multiplying the products. act .

[0076] In one optional embodiment, the calibrated closing time T of the drain valve 5 in the next operating cycle is controlled. off The drainage volume is controlled so that the drain valve 5 can drain all the water within the opening time of the next operating cycle, without causing the exhaust pressure to drop for a long time, causing pressure fluctuations and affecting the battery voltage.

[0077] S50, Set the preset water storage capacity M of the gas-water separator set According to the preset water storage capacity M set And actual drainage M act Adjust the drainage volume of drain valve 5 in the next operating cycle.

[0078] The liquid storage box in the gas-liquid separator has a maximum water storage capacity and a preset water storage capacity M. set It can be the maximum water storage capacity or half of the maximum water storage capacity; those skilled in the art can choose according to the actual situation.

[0079] In this embodiment, the calibrated closing time T of the drain valve 5 in the next operating cycle is adjusted. off Adjust the drainage volume of drain valve 5 in the next operating cycle.

[0080] Specifically, such as Figure 7 As shown, the calibrated closing time T of drain valve 5 in the next operating cycle off The adjustment method for ˊ includes the following steps:

[0081] S51, based on the actual drainage volume M act With preset water storage capacity M set The difference is used to calculate the adjustment value for the closing time of drain valve 5.

[0082] The method for calculating the adjustment value of the closing time of drain valve 5 is as follows: the adjustment value of the closing time of drain valve 5 is equal to the preset water storage capacity M. set With actual drainage M act The difference is divided by the actual water accumulation rate F of the gas-water separator.

[0083] The actual water accumulation rate F of the air-water separator is equal to the actual drainage volume M. act Divide by the calibrated closing time T off That is, F = M act / T off .

[0084] Therefore, the adjustment value for the closing time of drain valve 5 is: (M set-M act ) / F.

[0085] S52. Calculate the calibrated closing time T of drain valve 5 in the next operating cycle based on the adjustment value of the closing time of drain valve 5. off ˊ, Calibration shutdown time T in the next operating cycle off ˊ equals the calibrated shutdown time T in the previous operating cycle. off The sum of the adjustment value of the closing time of drain valve 5.

[0086] Calibration shutdown time T in the next operating cycle off ˊ=T off +(M set -M act ) / F=M set T off / M act .

[0087] It should be noted that the preset water storage capacity M set With actual drainage M act The difference can be positive or negative; therefore, the calculated calibration shutdown time T in the next operating cycle... off ˊMay be longer than the calibrated shutdown time T off The larger the drain valve 5, the longer its operating cycle; it may also be longer than the calibrated closing time T. off The smaller size shortens the operating cycle of drain valve 5.

[0088] In the next operating cycle, set the calibrated closing time of drain valve 5 to M. set T off / M act The designated drainage start time is T. wtr The calibrated exhaust opening time is T N2 If all these parameters remain unchanged, the water can be completely drained within the opening time of the drain valve 5 without causing a prolonged drop in exhaust pressure, resulting in pressure fluctuations and affecting the battery voltage.

[0089] like Figure 8 The diagram shows a comparison of the set value, actual value (actual value when water is completely drained), and calibrated closing time of drain valve 5 after adjustment. Ideally, during the operating cycle, the closing time of drain valve 5 is the calibrated closing time T. off The opening and drainage time of drain valve 5 is the calibrated opening and drainage time T. wtr The opening and venting time of drain valve 5 is the calibrated opening and venting time T. N2However, in actual operation, the actual drainage time may differ from the theoretical time due to factors such as real-time operating conditions, membrane electrode state, and ambient temperature. If the actual drainage time is too short, the actual venting time will increase, affecting the stability of the battery voltage. If the actual drainage time is too long, the drain valve 5 may close before all the water is drained. The remaining water will then enter the fuel cell stack under the influence of the hydrogen circulation pump, causing flooding of the fuel cell stack or damage to the hydrogen circulation pump. The calibrated closing time T of drain valve 5 in the next operating cycle... off ˊ, the calibration shutdown time T in the next operating cycle off ˊ Greater than the rated shutdown time T off For example, the operating cycle of drain valve 5 is extended.

[0090] The anode drainage method for fuel cells provided by this invention sets the calibrated closing time of the drainage valve 5 to T. off The calibrated opening time for drainage is T. wtr The calibrated exhaust opening time is T N2 The operating cycle of drain valve 5 is T. off +T wtr +T N2 During the operating cycle of drain valve 5, gas pressure changes are monitored. The actual drainage time T is the time from when drain valve 5 opens until a decrease in gas pressure is detected. wtr-act By comparing the actual drainage time T wtr-act The calibrated opening time for drainage is T wtr The operating cycle and / or drainage volume of drain valve 5 are dynamically adjusted. The anode drainage method of this fuel cell determines the water state (whether the water is completely drained or not) based on the gas pressure change cycle, thus determining the actual drainage time T. wtr-act Then, by comparing the actual drainage time T... wtr-act The calibrated opening time for drainage is T wtr The operating cycle and / or drainage volume of drain valve 5 are dynamically adjusted to ensure that the water at the fuel cell anode is completely drained within the next operating cycle of drain valve 5, while maintaining stable battery voltage. Real-time monitoring is implemented, and the operating cycle and / or drainage volume of drain valve 5 are dynamically adjusted based on the monitoring results to prevent membrane drying or flooding.

[0091] The above description is only a preferred embodiment of the present invention. For those skilled in the art, there will be changes in the specific implementation and application scope based on the ideas of the present invention. The content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for draining water from the anode of a fuel cell, characterized in that, Includes the following steps: The calibrated closing time of the drain valve (5) is set to T. off The calibrated drainage start time is T. wtr The calibrated exhaust opening time is T N2 The total opening time of the drain valve (5) is T. wtr +T N2 The operating cycle of the drain valve (5) is T. off +T wtr +T N2 During the closing time of the drain valve (5), the hydrogen and water discharged from the fuel cell stack (1) are separated by the gas-water separator (4). The separated hydrogen is recycled back into the fuel cell stack (1) through the outlet of the gas-water separator (4) under the action of the hydrogen circulation pump (3). The separated water is stored in the liquid storage box. When the drain valve (5) is opened, the water stored in the liquid storage box begins to be discharged. After the water is drained, the gas will be discharged through the drain valve (5). An inlet pressure sensor (6) is installed at the air inlet of the fuel cell stack (1), and an outlet pressure sensor (7) is installed at the air outlet. During the operating cycle, when the drain valve (5) is opened, it monitors the gas pressure change. The actual drainage time T is the time from when the drain valve (5) is opened until the pressure values ​​detected by the inlet pressure sensor (6) and the outlet pressure sensor (7) begin to decrease. wtr-act ; By comparing the actual drainage time T wtr-act With the calibrated opening drainage time T wtr The drainage volume of the drain valve (5) is dynamically adjusted and / or the calibrated opening drainage time T of the drain valve (5) in the next operating cycle is adjusted. wtr ˊ to adjust the operating cycle of the drain valve (5).

2. The fuel cell anode drainage method according to claim 1, characterized in that, The calibrated opening and drainage time T of the drain valve (5) in the next operating cycle wtr The adjustment method for ˊ includes the following steps: Determine the actual drainage time T wtr-act With the calibrated opening drainage time T wtr Are they the same? If the actual drainage time T wtr-act With the calibrated opening drainage time T wtr If they are different, then the calibration start-up drainage time T in the next operating cycle will be different. wtr ˊ equals the actual drainage time T during the previous operating cycle. wtr-act .

3. The fuel cell anode drainage method according to claim 1, characterized in that, The fuel cell anode drainage method further includes the following steps: During the operating cycle of the drain valve (5), when the drain valve (5) is open, while monitoring the change in gas pressure, the current pressure difference ΔP before and after the drain valve (5) is detected, and the current drainage flow rate Q is calculated based on the flow guiding capacity Kv of the drain valve (5) and the current pressure difference ΔP before and after the drain valve (5). Based on the actual drainage time T wtr-act The actual drainage volume M is calculated from the current drainage flow rate Q. act ; Set the preset water storage capacity M of the gas-water separator (4) set According to the preset water storage capacity M set and the actual drainage volume M act Adjust the drainage volume of the drain valve (5) in the next operating cycle.

4. The fuel cell anode drainage method according to claim 3, characterized in that, The formula for calculating the current drainage flow rate Q is: Q=Kv / (ρ / (1000△P)) 0.5 , Where: ρ is the density of water.

5. The fuel cell anode drainage method according to claim 3, characterized in that, The actual drainage volume M act The calculation formula is: M act =T wtr-act ×Q.

6. The fuel cell anode drainage method according to claim 3, characterized in that, By adjusting the calibrated closing time T of the drain valve (5) in the next operating cycle off Adjust the drainage volume of the drain valve (5) in the next operating cycle.

7. The fuel cell anode drainage method according to claim 6, characterized in that, The calibrated closing time T of the drain valve (5) in the next operating cycle off The adjustment method for ˊ includes the following steps: Based on the actual drainage volume M act With the preset water storage capacity M set The difference is used to calculate the adjustment value for the closing time of the drain valve (5); Calculate the calibrated closing time T of the drain valve (5) in the next operating cycle based on the adjustment value of the closing time of the drain valve (5). off The calibrated closing time T of the drain valve (5) in the next operating cycle off ˊ is equal to the calibrated shutdown time T in the previous operating cycle. off The sum of the adjustment value of the closing time of the drain valve (5).

8. The fuel cell anode drainage method according to claim 7, characterized in that, The adjustment value of the closing time of the drain valve (5) is equal to the actual drainage volume M. act With the preset water storage capacity M set The difference is divided by the actual water accumulation rate F of the gas-water separator (4).

9. The fuel cell anode drainage method according to claim 8, characterized in that, The actual water accumulation rate F of the gas-water separator (4) is equal to the actual drainage volume M. act Divide by the calibrated closing time T off .

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