A tail exhaust device for a fuel cell and an exhaust control method thereof

Abstract

The present invention relates to the field of fuel cell technology, and discloses a fuel cell tail exhaust device and an exhaust control method thereof, comprising a box, an air inlet, an exhaust port, a movable plate, a gas collecting chamber, an exhaust chamber, a hydrogen exhaust port and a water outlet; a movable plate that is lifted and lowered along the height direction of the box is provided in the box, and the movable plate divides the box into a gas collecting chamber and an exhaust chamber; the air inlet and the exhaust port are relatively arranged at the two ends of the box, the air inlet is connected to the gas collecting chamber, and the exhaust port is connected to the exhaust chamber; the hydrogen exhaust port is connected to the top of the gas collecting chamber, and the water outlet is connected to the bottom of the box. The present invention processes the tail gas of the fuel cell system by setting the movable plate, the gas collecting chamber and the exhaust chamber, so that the concentration of hydrogen contained in the exhaust gas is greatly reduced, so that the vehicle can be used normally even in a closed environment and a factory area, and the risk of explosion caused by accumulation of hydrogen in a closed environment is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a tail exhaust device for a fuel cell and an exhaust control method thereof. Background Art

[0002] Fuel cells have broad development prospects in the field of new energy technology due to their advantages such as high energy conversion efficiency, environmental protection and pollution-free, fuel diversity, mobility and flexibility, and long life. Vehicles such as forklifts and commercial vehicles all have corresponding fuel cell vehicles.

[0003] The exhaust gas produced by fuel cells is generally discharged directly. The exhaust gas contains hydrogen, nitrogen, oxygen and water vapor. There is no problem in discharging it in an open environment. However, in some closed environments or some high-demand factory areas, there are strict standards for hydrogen emissions. The accumulated hydrogen can easily cause safety accidents. Therefore, there is an urgent need for a tail exhaust device that can separate the hydrogen from the nitrogen and oxygen in the exhaust gas to ensure that the exhaust gas does not cause safety hazards. Summary of the invention

[0004] The present invention aims to solve the above problems and provides a tail exhaust device for a fuel cell and an exhaust control method thereof, so as to solve the problem that the existing tail exhaust device can only store water but cannot discharge hydrogen separately from nitrogen and oxygen.

[0005] To achieve this object, the present invention adopts the following technical solutions: A tail exhaust device for a fuel cell, comprising a box body, an air inlet, an exhaust port, a movable plate, a gas collecting cavity, an exhaust cavity, a hydrogen exhaust port and a water outlet; The box body is provided with a movable plate which is lifted and lowered along the height direction of the box body, the movable plate divides the box body into a gas collecting chamber and an exhaust chamber, and the movable plate is at different height positions according to the running state of the vehicle; The air inlet and the exhaust port are arranged at two ends of the box body opposite to each other, the air inlet is connected to the air collecting cavity, and the exhaust port is connected to the exhaust cavity; The hydrogen discharge port is connected to the top of the gas collecting chamber, and the water discharge port is connected to the bottom of the gas collecting chamber.

[0006] Preferably, the movable plate is tangent to the bottom of the box when it is at the maximum descending height.

[0007] Preferably, it further comprises a first water guide plate; The first water guide plate is arranged parallel to the movable plate; The top end of the first water guide plate is connected to the top of the air collecting cavity, the bottom end is located in the air collecting cavity, and the bottom end of the first water guide plate is lower than the height position of the air inlet; The first water guide plate is a mesh structure.

[0008] Preferably, a hydrogen concentration sensor is further included, wherein the hydrogen concentration sensor is connected to the inner wall of the gas collecting cavity and is located below the gas inlet.

[0009] Preferably, it also includes a second water guide plate; The second water guide plate is obliquely arranged in the exhaust cavity, and two ends of the second water guide plate are respectively connected to the inner side wall of the exhaust cavity; The projection area of ​​the second water guide plate on the box body covers the exhaust port.

[0010] Preferably, it also includes a liquid level sensor for monitoring the liquid level in the gas collecting chamber, and the sensor is installed on the box body.

[0011] An exhaust control method for a tail exhaust device, applied to the tail exhaust device as described above, comprises the following control steps: Obtain the vehicle's operating power and determine the vehicle's operating status; The operating state of the vehicle includes: a low-power operating state and a high-power operating state; Setting a first control strategy and a second control strategy; Among them, the first control strategy adjusts the movable plate up and down based on the vehicle operating power; The second control strategy is to adjust the movable plate up and down based on the liquid level and hydrogen concentration in the gas collecting chamber; When the vehicle is in a low-power operating state, a first control strategy is selected to control the exhaust of the tail exhaust device; When the vehicle is in a high-power operating state, the second control strategy is selected to control the exhaust of the tail exhaust device.

[0012] Preferably, the first control strategy comprises the following steps: Get the low power range of vehicle operation; Divide the low power range into equal power to obtain p intervals; The p intervals correspond to different descending heights of the movable plate respectively; In the low power range, the power at which the vehicle operates is proportional to the height to which the movable panel is lowered.

[0013] Preferably, the first control strategy further comprises the following steps: When the end of the movable plate close to the bottom of the box body is not in contact with the liquid surface in the box body, the air inlet and the exhaust port are both in an open state, and the hydrogen discharge port and the water discharge port are both in a closed state; When one end of the movable plate close to the bottom of the box body contacts the liquid surface in the box body, the control steps include: Keep the air inlet and outlet open, and open the drain; When the liquid level in the box is 0, close the air inlet, exhaust port and drain port, and open the hydrogen discharge port.

[0014] Preferably, the second control strategy includes the following control steps: Setting a first liquid level threshold, a second liquid level threshold, a hydrogen concentration threshold and a preset height; The movable plate is adjusted to the maximum descending height; When the liquid level in the box does not reach the first liquid level threshold, the air inlet and the exhaust port are both in an open state, and the hydrogen discharge port and the water discharge port are both in a closed state; When the liquid level in the box reaches a first liquid level threshold, the drain port is opened and the air inlet is closed; When the liquid level in the tank drops to a second liquid level threshold, the movable plate is lifted upward to a preset height and the hydrogen discharge port is opened; When the hydrogen concentration drops to a hydrogen concentration threshold, the movable plate is adjusted to the maximum descending height, the water outlet and the hydrogen outlet are closed, and the air inlet is opened.

[0015] The contribution of the present invention is that the exhaust gas of the fuel cell system is processed by setting up a movable plate, a gas collecting chamber and an exhaust chamber, so that the concentration of hydrogen contained in the exhaust gas is greatly reduced, so that the vehicle can be used normally even in a closed environment and a factory area, and the risk of explosion caused by accumulation of hydrogen in a closed environment is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the internal structure of the tail exhaust device of the present invention; Figure 2 It is a schematic structural diagram of the tail exhaust device of the present invention; Figure 3 is a flow chart of the exhaust control method of the tail exhaust device of the present invention; Figure 4 is a graph showing the relationship between the low power range of the present invention and the height at which the movable plate is lowered; Figure 5 It is a structural schematic diagram of one embodiment of the present invention; Figure 6 yes Figure 5 Schematic diagram of the internal structure; Among them: box body 10, air inlet 20, exhaust port 30, movable plate 40, gas collecting chamber 50, exhaust chamber 60, hydrogen exhaust port 70, water discharge port 80, first water guide plate 1a, hydrogen concentration sensor 1b, second water guide plate 1c, liquid level sensor 1d, liquid level control port 1e. DETAILED DESCRIPTION

[0017] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The drawings provide embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing the embodiments of the present invention and are not intended to limit this application.

[0019] It is understood that the terms "first", "second", etc. used in this application can be used in this article to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element. It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element, or connected to the other element through an intermediate element. In addition, the "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc. if there is a transmission of electrical signals or data between the connected objects.

[0020] When used herein, the singular forms "a", "a person" and "the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" etc. specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof.

[0021] like Figure 1-2 As shown, a tail exhaust device for a fuel cell includes a box body 10, an air inlet 20, an exhaust port 30, a movable plate 40, a gas collecting chamber 50, an exhaust chamber 60, a hydrogen exhaust port 70 and a water outlet 80; The box body 10 is provided with a movable plate 40 that is lifted and lowered along the height direction of the box body 10 (the top end of the movable plate 40 is connected to the box body 10, and the bottom end is lifted and lowered in the box body 10. The movable plate 40 can be lifted and lowered by a spring connection or driven by a motor), and the movable plate 40 divides the box body 10 into a gas collecting chamber 50 and an exhaust chamber 60 (the volume of the gas collecting chamber 50 is larger than that of the exhaust chamber 60, and the volume ratio is between 3:1-4:1). The movable plate 40 is at different height positions according to the running state of the vehicle; The air inlet 20 and the exhaust port 30 are disposed at opposite ends of the box body 10 , the air inlet 20 is connected to the gas collecting chamber 50 , and the exhaust port 30 is connected to the exhaust chamber 60 ; The hydrogen discharge port 70 is connected to the top of the gas collecting chamber 50 , and the water discharge port 80 is connected to the bottom of the gas collecting chamber 50 .

[0022] The tail exhaust device of the present invention can be used for fuel cell system vehicles, including commercial vehicles, passenger vehicles and forklifts. The tail exhaust device is used to collect the exhaust gas generated during the operation of the vehicle and separate the hydrogen, nitrogen, oxygen and water vapor in the exhaust gas, so that the hydrogen content in the tail exhaust gas is extremely low, so that the fuel cell vehicle can be used normally even in a closed environment or factory area.

[0023] Specifically, the air inlet 20 of the tail exhaust device is connected to the tail exhaust pipe of the fuel cell system, and the tail gas enters the box body 10 from the air inlet 20. The movable plate 40 in the box body 10 divides the box body 10 into a gas collecting chamber 50 and an exhaust chamber 60, wherein the gas collecting chamber 50 can be used to collect and store gas, and the exhaust chamber 60 is connected to the exhaust port 30, and can lead the separated oxygen and nitrogen out of the box body 10. The water outlet 80 is arranged at the bottom of the gas collecting chamber 50, and can discharge the liquid water in the box body 10. The hydrogen discharge port 70 is arranged above the gas collecting chamber 50 and is connected to the gas collecting chamber 50, and can discharge the separated hydrogen in the gas collecting chamber 50 from the gas collecting chamber 50. Further explanation: the hydrogen discharge port 70 is connected to the ejector, and the hydrogen flowing out of the hydrogen discharge port 70 can enter the ejector and be introduced into the fuel cell stack to participate in the reaction.

[0024] The exhaust gas contains hydrogen, nitrogen, oxygen and water vapor. When the exhaust gas enters the gas collecting chamber 50, the water vapor will liquefy at the bottom of the gas collecting chamber 50. Since hydrogen is lighter than nitrogen and oxygen, hydrogen will gradually accumulate at the top of the gas collecting chamber 50, followed by nitrogen and oxygen respectively. When the gas collecting chamber 50 discharges gas to the exhaust chamber 60 (the movable plate 40 will be at different heights according to the different operating conditions of the vehicle), oxygen first enters the exhaust chamber 60 and is discharged to the outside through the exhaust port 30, followed by nitrogen entering the exhaust chamber 60 and being discharged to the outside through the exhaust port 30. After the oxygen and nitrogen are discharged, the hydrogen is guided out of the gas collecting chamber 50 through the hydrogen discharge port 70, thereby completing the treatment of the exhaust gas of the fuel cell system and reducing the concentration of hydrogen in the exhaust gas, so that the vehicle can be used normally even in a closed environment and a factory area, reducing the risk of explosion caused by the accumulation of hydrogen in a closed environment.

[0025] To further illustrate this embodiment, the movable plate 40 is tangent to the bottom of the box body 10 when it is at the maximum descending height.

[0026] When the vehicle is in a high-power operating state, the exhaust gas has a large flow rate and a fast flow rate. At this time, the movable plate 40 needs to be adjusted to the maximum descent height to completely block the gas collecting chamber 50 and the exhaust chamber 60 to prevent hydrogen from flowing into the exhaust chamber 60 under a large flow rate and high flow rate environment and being discharged to the outside.

[0027] Further description of this embodiment further includes a first water guide plate 1a; The first water guide plate 1a is arranged parallel to the movable plate 40; The top of the first water guide plate 1a is connected to the top of the air collecting cavity 50, and the bottom is located in the air collecting cavity 50, and the bottom of the first water guide plate 1a is lower than the height of the air inlet 20; The first water guide plate 1a is a mesh structure.

[0028] Specifically, the first water guide plate 1a is arranged in parallel with the movable plate 40, that is, the first water guide plate 1a and the air inlet 20 are arranged perpendicular to each other (the movable plate 40 and the air inlet 20 are also arranged perpendicular to each other). When the air volume is large and the flow rate is fast, the flow rate of the exhaust gas can be greatly slowed down, which is convenient for the exhaust gas to be stratified in the air collecting chamber 50. The first water guide plate 1a can not only slow down the flow rate of the exhaust gas, but also protect the movable plate 40, so as to prevent the movable plate 40 from being directly hit by the high-speed airflow and to prevent the movable plate 40 from being unable to be raised or lowered.

[0029] To further explain, the horizontal distance from the first water guide plate 1a to the air inlet 20 is smaller than the horizontal distance from the first water guide plate 1a to the movable plate 40, and the bottom end of the first water guide plate 1a is lower than the height position of the air inlet 20, ensuring that all exhaust gas flowing in from the air inlet 20 passes through the first water guide plate 1a and is slowed down by the first water guide plate 1a.

[0030] The first water guide plate 1a is a mesh structure, which can reduce the exhaust gas flow rate while allowing the water vapor in the exhaust gas to condense on the mesh mouth, thereby accelerating the liquefaction time of the water vapor in the exhaust gas and quickly separating the water vapor from hydrogen, nitrogen and oxygen. The water droplets condensed on the mesh mouth will drip downward along the bottom end of the first water guide plate 1a to the bottom of the box 10, thereby gradually increasing the volume of liquid water at the bottom of the box 10.

[0031] To further illustrate this embodiment, a hydrogen concentration sensor 1 b is further included. The hydrogen concentration sensor 1 b is connected to the inner wall of the gas collecting cavity 50 and is located below the gas inlet 20 .

[0032] Specifically, the tail exhaust device also includes a controller, which is arranged on the outer surface of the box body 10. The controller can receive a signal from the hydrogen concentration sensor 1b and adjust the movable plate 40 up and down according to the signal from the hydrogen concentration sensor 1b.

[0033] Further description of this embodiment further includes a second water guide plate 1c; The second water guide plate 1c is obliquely disposed in the exhaust cavity 60, and both ends of the second water guide plate 1c are respectively connected to the inner side wall of the exhaust cavity 60; The horizontal projection area of ​​the second water guide plate 1 c on the box body 10 covers the exhaust port 30 .

[0034] The second water guide plate 1c can further dehumidify the gas that is about to be discharged from the exhaust chamber 60 (the second water guide plate 1c is set according to environmental needs. If the external environment has high requirements on humidity, several second water guide plates 1c parallel to each other can be set in the exhaust chamber 60), so that the discharged gas (mainly nitrogen and oxygen) can maintain a sufficient degree of dryness. On the other hand, the second water guide plate 1c is inclined (preferably 45°). The inclined setting can increase the contact area between the second water guide plate 1c and the tail exhaust gas, ensuring that the tail exhaust gas is dehydrated as much as possible. Furthermore, the horizontal projection area of ​​the second water guide plate 1c on the box body 10 covers the exhaust port 30, ensuring that no gas will be discharged directly from the exhaust port 30 without passing through the second water guide plate 1c, so that all tail exhaust gases are dehydrated through the second water guide plate 1c, and the gas coming out of the exhaust chamber 60 maintains a certain degree of dryness.

[0035] To further illustrate this embodiment, a liquid level sensor 1d for monitoring the liquid level in the gas collecting chamber 50 is also included, and the sensor is installed on the box body 10.

[0036] The liquid level sensor 1d can monitor the liquid level of the liquid water in the box body 10. The liquid level sensor 1d is electrically connected to the controller. After receiving the signal from the liquid level sensor 1d, the controller adjusts the air inlet 20, the exhaust port 30, the movable plate 40, the hydrogen discharge port 70 and the water discharge port 80 to ensure that the gas in the gas collecting chamber 50 can be discharged smoothly.

[0037] like Figure 2 As shown, an exhaust control method for a tail exhaust device is applied to the above-mentioned tail exhaust device, and includes the following control steps: Obtain the vehicle's operating power and determine the vehicle's operating status; The operating state of the vehicle includes: a low-power operating state and a high-power operating state; Setting a first control strategy and a second control strategy; Among them, the first control strategy adjusts the movable plate 40 up and down based on the vehicle operating power; The second control strategy is to adjust the movable plate 40 up and down based on the liquid level and hydrogen concentration in the gas collecting chamber 50; When the vehicle is in a low-power operating state, a first control strategy is selected to control the exhaust of the tail exhaust device; When the vehicle is in a high-power operating state, the second control strategy is selected to control the exhaust of the tail exhaust device.

[0038] The present invention can select different control strategies to adjust the movable plate 40 according to different operating states of the vehicle, so as to facilitate the subsequent classified discharge of the gas in the tail exhaust device, thereby ensuring that the hydrogen in the gas collecting cavity 50 can be smoothly separated from the nitrogen and oxygen under different working conditions, avoiding excessive hydrogen in the gas discharged from the tail exhaust device.

[0039] like Figure 3 As shown, to further illustrate this embodiment, the first control strategy includes the following steps: Get the low power range of vehicle operation; Divide the low power range into equal power to obtain p intervals; The p intervals correspond to different descending heights of the movable plate 40 respectively; In the low power range, the power of the vehicle operation is proportional to the descending height of the movable panel 40 .

[0040] This embodiment is described by taking a forklift as an example. The low power range of a 10t forklift is 0-9kw. The low power range of the forklift is divided into equal power. In this embodiment, it is divided into p=3 intervals, namely 0-3kw, 3kw-6kw, and 6kw-9kw. The height position of the movable plate 40 corresponding to each interval is different. For example, the lowering height of the movable plate 40 corresponding to the 0-3kw interval is 15cm (the lowering height is adjusted based on the minimum lowering height of the movable plate 40, which is 0. When the lowering height of the movable plate 40 is 0, the bottom end of the movable plate 40 is at the same level as the lowest point of the air inlet 20). The descending height of the movable plate 40 corresponding to the 3kw-6kw range is 30cm, and the descending height of the movable plate 40 corresponding to the 6kw-9kw range is 45cm. The higher the height of the movable plate 40 descends, the closer the distance between the movable plate 40 and the bottom of the box body 10 is. Since the higher the power of the vehicle, the higher the hydrogen content in the exhaust gas, and the greater the flow rate and flow velocity of the exhaust gas, the greater the probability of hydrogen flowing into the exhaust chamber 60 from the bottom of the movable plate 40. Therefore, in this embodiment, the power of the vehicle operation and the descending height of the movable plate 40 are set to be proportional to each other to prevent a large amount of hydrogen from leaking from the bottom of the movable plate 40 into the exhaust chamber 60.

[0041] To further illustrate this embodiment, the first control strategy also includes the following control steps: When the end of the movable plate 40 close to the bottom of the box 10 (i.e., the bottom end of the movable plate 40) is not in contact with the liquid surface in the box 10, the air inlet 20 and the exhaust port 30 are both in an open state, and the hydrogen discharge port 70 and the water discharge port 80 are both in a closed state; When one end of the movable plate 40 close to the bottom of the box body 10 contacts the liquid surface in the box body 10, the following control steps are included: Keep the air inlet 20 and the air outlet open, and open the drain port 80; When the liquid level in the box 10 is 0 (nitrogen and oxygen are also basically exhausted), the air inlet 20, the exhaust port 30 and the drain port 80 are closed, and the hydrogen exhaust port 70 is opened.

[0042] To further illustrate this embodiment, when the vehicle is in the power range of 0-3kw, due to the small power of the vehicle, the exhaust gas flow entering the gas collecting chamber 50 through the air inlet 20 is small and the flow rate is slow, hydrogen will accumulate at the top of the gas collecting chamber 50, and nitrogen and oxygen will flow into the exhaust chamber 60 through the space below the movable plate 40 (the movable plate 40 is lowered to a height of 45cm), and be discharged to the outside atmosphere through the exhaust port 30. As the exhaust gas continues to flow into the box body 10, liquid water will accumulate at the bottom of the box body 10, and the liquid level of the liquid water will gradually increase with the passage of time. When the bottom end of the movable plate 40 contacts the liquid water, it means that the hydrogen in the gas collecting chamber 50 has accumulated to a certain extent (the corresponding hydrogen accumulation amount in the gas collecting chamber 50 at different heights has been tested in advance, and the height can be set according to the experimental data table). At this time, drainage and exhaust can be performed separately according to the first control strategy.

[0043] When the vehicle changes load in the low power range, the power may increase or decrease. The 3kw-6kw range is taken as an example here. When the vehicle power changes from the 3kw-6kw range to the 6kw-9kw range, the movable plate 40 moves downward. If the movable plate 40 does not contact the liquid surface when it is lowered to the specified height position, the working state of the water collecting tank in the 3kw-6kw range is maintained (that is, the air inlet 20, the exhaust port 30, the hydrogen discharge port 70 and the water discharge port 80 all maintain the current state) until the bottom end of the movable plate 40 contacts the rising liquid surface, and the first control strategy is adopted to discharge the gas and water in the water collecting tank separately. If the movable plate 40 directly contacts the liquid surface when it is lowered to the specified height position, the above-mentioned first control strategy is immediately adopted to discharge the gas and water in the water collecting tank separately.

[0044] When the vehicle power changes from the 3kw-6kw range to the 0-3kw range, the movable plate 40 is lifted upward at this time, and the distance between the movable plate 40 and the liquid level at the bottom of the box body 10 increases. Therefore, the working state of the water collecting tank in the 3kw-6kw range is maintained until the bottom end of the movable plate 40 contacts the rising liquid level, and the first control strategy is used to discharge the gas and water in the water collecting tank respectively.

[0045] To further illustrate this embodiment, the second control strategy includes the following control steps: Set the first liquid level threshold, the second liquid level threshold, the hydrogen concentration threshold and the preset height (based on factors such as the volume of the box 10, the load power, and the exhaust gas flow rate); The movable plate 40 is adjusted to the maximum descending height (at this time, the bottom end of the movable plate 40 is tangent to the bottom of the box body 10); When the liquid level in the box body 10 does not reach the first liquid level threshold, the air inlet 20 and the exhaust port 30 are both in an open state, and the hydrogen discharge port 70 and the water discharge port 80 are both in a closed state; When the liquid level in the box 10 reaches a first liquid level threshold, the drain port 80 is opened and the air inlet 20 is closed; When the liquid level in the tank 10 drops to the second liquid level threshold, the movable plate 40 is lifted upward to a preset height and the hydrogen discharge port 70 is opened; When the hydrogen concentration decreases to a hydrogen concentration threshold, the movable plate 40 is adjusted to a maximum descending height, the water discharge port 80 and the hydrogen discharge port 70 are closed, and the air inlet 20 is opened.

[0046] When the vehicle is in a high-power state, the exhaust gas flow is large and the flow rate is fast. In order to prevent the exhaust gas from entering the exhaust chamber 60 through the bottom of the movable plate 40, the movable plate 40 is directly adjusted to the maximum descending height, that is, the bottom end of the movable plate 40 is kept tangent to the box body 10. At this time, the exhaust gas can only stay in the gas collecting chamber 50, and the water vapor is liquefied and accumulated at the bottom of the gas collecting chamber 50. When the liquid level reaches the first liquid level threshold (the first liquid level threshold is higher than the second liquid level threshold), it means that the hydrogen in the gas collecting chamber 50 needs to be discharged. However, since the air pressure in the gas collecting chamber 50 is relatively high at this time, in order to prevent the movement of the movable plate 40 from being obstructed, the drain port 80 is first opened to allow part of the liquid water to be discharged from the gas collecting chamber 50, thereby reducing the pressure in the gas collecting chamber 50. When the liquid level drops to the second liquid level threshold, the pressure in the gas collecting chamber 50 is not It will affect the vertical movement of the movable plate 40, so it is lifted up to a preset height, and the hydrogen discharge port 70 is opened at the same time. The oxygen and nitrogen above the liquid surface are squeezed into the exhaust chamber 60 through the bottom end of the movable plate 40 under the pressure of the top hydrogen, and discharged to the external environment through the exhaust port 30. The hydrogen at the top of the gas collecting chamber 50 is transported to the ejector through the hydrogen discharge port 70. When the hydrogen concentration is reduced to the hydrogen concentration threshold, it means that the high-purity hydrogen in the gas collecting chamber 50 has been discharged. At this time, the purity of the hydrogen in the gas collecting chamber 50 is not high (it contains some nitrogen and oxygen, which does not meet the gas standard for the ejector). At this time, the movable plate 40 is readjusted to the maximum descending height, and the water outlet 80, the exhaust port 30 and the hydrogen discharge port 70 are closed. The air inlet 20 is opened to continue to store and process the exhaust gas of the fuel cell system.

[0047] In another embodiment of the present invention, Figure 5-6 As shown, a liquid level control port 1e is further provided below the exhaust port 30, and the liquid level control port 1e is communicated with the exhaust chamber 60; Further description also includes a third control strategy, which does not consider the running state of the vehicle, and the third control strategy adjusts the movable plate 40 up and down based on the liquid level in the box 10; Specifically, the third control strategy includes the following control steps: Set the third liquid level threshold (the height position of the third liquid level threshold is lower than the height position of the liquid level control port 1e), the liquid level level and the hydrogen peak value; The movable plate 40 is adjusted to the maximum descending height, the air inlet 20 and the exhaust port 30 are opened, and the hydrogen discharge port 70 and the water discharge port 80 are closed; When the liquid level in the gas collecting chamber 50 rises to the third liquid level threshold, the movable plate 40 is adjusted to a level height of the liquid level (part of the liquid water in the gas collecting chamber 50 flows into the exhaust chamber 60, and the liquid level decreases. The specific decrease can be calculated based on the volumes of the box body 10, the gas collecting chamber 50 and the exhaust chamber 60, so the level height of the liquid level can also be calculated), and the end of the movable plate 40 close to the bottom of the box body 10 is always kept tangent to the liquid surface in the box body 10 (when the liquid level rises, the end of the movable plate 40 close to the bottom of the box body 10 also continues to rise); When the liquid level in the box 10 rises to the height of the liquid level control port 1e, the liquid level control port 1e is opened (the liquefied liquid water and the liquid water pressed by the gas collecting chamber 50 will be discharged from the liquid level control port 1e, and part of the nitrogen and oxygen pressed together with the liquid water will also be discharged from the liquid level control port 1e); When the hydrogen concentration in the gas collecting chamber 50 reaches the hydrogen peak, the air inlet 20, the exhaust port 30 and the liquid level control port 1e are closed, and the drain port 80 is opened; When the liquid level in the box 10 drops to 0, the water discharge port 80 is closed and the hydrogen discharge port 70 is opened; When the hydrogen concentration in the gas collecting chamber 50 decreases to a hydrogen concentration threshold, the hydrogen exhaust port 70 is closed, the movable plate 40 is adjusted to a maximum descending height, and the air inlet 20 and the air exhaust port 30 are opened.

[0048] Further explanation, in this embodiment, a liquid level control port 1e is provided at one end of the box body 10, so that the height of the liquid level in the box body 10 will not exceed the liquid level control port 1e. After the tail gas is stratified in the gas collecting chamber 50, the nitrogen and oxygen at the bottom will gradually be squeezed into the exhaust chamber 60 under the pressure of hydrogen for discharge, so that the hydrogen concentration in the gas collecting chamber 50 continues to increase. When the hydrogen concentration reaches the hydrogen peak, the tail gas is stopped from entering the box body 10, and the drain port 80 is opened to discharge all the liquid water accumulated in the box body 10 (some of the nitrogen and oxygen at the bottom will also be discharged along with the liquid water during the discharge process). When only the gas collecting chamber 50 is filled with water, the exhaust gas will be discharged. After hydrogen is left, the hydrogen discharge port 70 is opened, and the high-purity hydrogen in the gas collecting chamber 50 is introduced into the ejector for recycling. The third control strategy in this embodiment requires that the movable plate 40 has a higher precision (generally, the third control strategy is adopted for new equipment, and the precision of new equipment is relatively better). When the liquid level has not reached the height of the liquid level control port 1e, it is necessary to always keep it tangent to the liquid level at the bottom of the box body 10. Through the third control strategy, the hydrogen in the exhaust gas can be separated simply and quickly, and the hydrogen can be recycled to ensure that hydrogen accumulation will not occur in the vehicle in a closed environment or in the factory area, greatly reducing the risk of explosion.

[0049] Although the present invention is disclosed through the above embodiments, the protection scope of the present invention is not limited thereto. Without departing from the concept of the present invention, any deformation, replacement, etc. made to the above components shall fall within the scope of the claims of the present invention.

Claims

1. A tail exhaust device for a fuel cell, characterized in that: It includes a box body, an air inlet, an exhaust port, a movable plate, a gas collecting cavity, an exhaust cavity, a hydrogen exhaust port and a water outlet; The box body is provided with a movable plate which is lifted and lowered along the height direction of the box body, the movable plate divides the box body into a gas collecting chamber and an exhaust chamber, and the movable plate is at different height positions according to the running state of the vehicle; The air inlet and the exhaust port are arranged at two ends of the box body opposite to each other, the air inlet is connected to the air collecting cavity, and the exhaust port is connected to the exhaust cavity; The hydrogen discharge port is connected to the top of the gas collecting chamber, and the water discharge port is connected to the bottom of the gas collecting chamber.

2. A tail exhaust device for a fuel cell according to claim 1, characterized in that: The movable plate is tangent to the bottom of the box when it is at the maximum descending height.

3. A tail exhaust device for a fuel cell according to claim 1, characterized in that: Also includes a first water guide plate; The first water guide plate is arranged parallel to the movable plate; The top end of the first water guide plate is connected to the top of the air collecting cavity, the bottom end is located in the air collecting cavity, and the bottom end of the first water guide plate is lower than the height position of the air inlet; The first water guide plate is a mesh structure.

4. A tail exhaust device for a fuel cell according to claim 1, characterized in that: It also includes a hydrogen concentration sensor, which is connected to the inner wall of the gas collecting cavity and is located below the gas inlet.

5. A tail exhaust device for a fuel cell according to claim 1, characterized in that: Also includes a second water guide plate; The second water guide plate is obliquely arranged in the exhaust cavity, and two ends of the second water guide plate are respectively connected to the inner side wall of the exhaust cavity; The projection area of ​​the second water guide plate on the box body covers the exhaust port.

6. A tail exhaust device for a fuel cell according to claim 1, characterized in that: It also includes a liquid level sensor for monitoring the liquid level in the gas collecting cavity, and the sensor is installed on the box body.

7. An exhaust control method for a tail exhaust device, applied to the tail exhaust device as claimed in any one of claims 1 to 6, characterized in that: The control steps include: Obtain the vehicle's operating power and determine the vehicle's operating status; The operating state of the vehicle includes: a low-power operating state and a high-power operating state; Setting a first control strategy and a second control strategy; Among them, the first control strategy adjusts the movable plate up and down based on the vehicle operating power; The second control strategy is to adjust the movable plate up and down based on the liquid level and hydrogen concentration in the gas collecting chamber; When the vehicle is in a low-power operating state, a first control strategy is selected to control the exhaust of the tail exhaust device; When the vehicle is in a high-power operating state, the second control strategy is selected to control the exhaust of the tail exhaust device.

8. The exhaust gas control method according to claim 7, characterized in that: The first control strategy comprises the following steps: Get the low power range of vehicle operation; Divide the low power range into equal power to obtain p intervals; The p intervals correspond to different descending heights of the movable plate respectively; In the low power range, the power at which the vehicle operates is proportional to the height to which the movable panel is lowered.

9. The exhaust gas control method according to claim 8, characterized in that: The first control strategy also includes the following steps: When the end of the movable plate close to the bottom of the box body is not in contact with the liquid surface in the box body, the air inlet and the exhaust port are both in an open state, and the hydrogen discharge port and the water discharge port are both in a closed state; When one end of the movable plate close to the bottom of the box body contacts the liquid surface in the box body, the control steps include: Keep the air inlet and outlet open, and open the drain; When the liquid level in the box is 0, close the air inlet, exhaust port and drain port, and open the hydrogen discharge port.

10. The exhaust gas control method according to claim 7, characterized in that: The second control strategy includes the following control steps: Setting a first liquid level threshold, a second liquid level threshold, a hydrogen concentration threshold and a preset height; The movable plate is adjusted to the maximum descending height; When the liquid level in the box does not reach the first liquid level threshold, the air inlet and the exhaust port are both in an open state, and the hydrogen discharge port and the water discharge port are both in a closed state; When the liquid level in the box reaches a first liquid level threshold, the drain port is opened and the air inlet is closed; When the liquid level in the tank drops to a second liquid level threshold, the movable plate is lifted upward to a preset height and the hydrogen discharge port is opened; When the hydrogen concentration drops to a hydrogen concentration threshold, the movable plate is adjusted to the maximum descending height, the water outlet and the hydrogen outlet are closed, and the air inlet is opened.

Images