A control system for automatically following hydrogen and air pressure of a fuel cell

Abstract

The application discloses a kind of control systems of fuel cell hydrogen air pressure automatic following, comprising: hydrogen air fuel cell stack, hydrogen supply subsystem, air supply subsystem and tail gas treatment subsystem;Hydrogen supply subsystem is communicated with hydrogen air fuel cell stack by hydrogen import, air supply subsystem is communicated with hydrogen air fuel cell stack by air import;Hydrogen air fuel cell stack is used to carry out electrochemical reaction based on hydrogen provided by hydrogen supply subsystem and air provided by air supply subsystem;Tail gas treatment subsystem is communicated with hydrogen air fuel cell stack by air outlet and hydrogen outlet, for treating tail gas generated after hydrogen air fuel cell stack reaction.The present application realizes the automatic following control of fuel cell system hydrogen air pressure, solves the problem that traditional fuel cell system lacks mechanical structure guarantee, and when electric control system fails or malfunctions, hydrogen air pressure difference imbalance and stack damage may occur.

Description

Technical Field

[0001] This invention belongs to the technical field of proton exchange membrane hydrogen-air fuel cell systems, and particularly relates to a control system for automatic hydrogen-air pressure following in fuel cells. Background Technology

[0002] A fuel cell system is a device that directly converts the chemical energy of fuel (hydrogen) into electrical energy. It mainly includes: a fuel cell stack, the core component of the fuel cell system, consisting of individual cells connected in series, including membrane electrode assemblies (anode, cathode, and proton exchange membrane) and current collectors; an air supply subsystem, which supplies air to the cathode of the fuel cell at a suitable pressure, flow rate, humidity, and temperature through methods such as air pressurization, humidification, and back pressure regulation; a hydrogen supply subsystem, which supplies hydrogen to the anode of the fuel cell at a suitable pressure, flow rate, humidity, and temperature through methods such as gas depressurization and circulation; and a hydrothermal management subsystem, which supplies coolant to the water side of the fuel cell at a suitable pressure, flow rate, and temperature through methods such as coolant filtration and circulation.

[0003] Proton exchange membrane fuel cells (PEMFCs) place extremely high demands on the proton exchange membrane, requiring it to possess excellent proton conductivity, good thermal and chemical stability, low gas permeability, and sufficiently high mechanical and structural strength. During normal operation, the membrane electrode assembly (MEA) is subjected to pressure from hydrogen, air, and coolant. This pressure fluctuates continuously with changes in the load current. Excessive pressure on one side, resulting in a large pressure differential, can damage the MEA assembly, ultimately leading to the destruction of the entire fuel cell stack.

[0004] Currently, the cathode gas supply in fuel cell systems is typically an air compressor, while the anode gas supply is usually a high-pressure hydrogen cylinder. The operating pressures of the anode and cathode are controlled independently. Specifically, the cathode operating pressure is determined by calibrating the air compressor speed and back pressure valve opening under different operating conditions on a test bench, and the anode operating pressure is determined by calibrating the hydrogen supply and return pressure assembly. However, in actual operation, due to issues with the accuracy of control calculations and time lags, especially when the fuel cell's operating conditions change or the exhaust valve opens, the hydrogen-air pressure cannot be perfectly synchronized. In severe cases, this can even cause back pressure due to the hydrogen-air pressure difference. Over time, this can easily damage the membrane electrode assembly under frequent alternating stress, seriously affecting the normal operation and lifespan of the fuel cell. Currently, besides reducing this pressure difference fluctuation through methods such as optimizing PID control, there is no mechanical method to control the fuel cell hydrogen-air pressure and achieve pressure synchronization. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a control system for automatic hydrogen-air pressure following in fuel cells. This system aims to achieve automatic hydrogen-air pressure following control in fuel cell systems, solving the problem that traditional fuel cell systems, due to the lack of mechanical structural protection, may lead to hydrogen-air pressure imbalance and stack damage if the electronic control system fails or malfunctions.

[0006] To address the aforementioned technical problems, this invention discloses a control system for automatic hydrogen-air pressure following in a fuel cell, comprising: a hydrogen-air fuel cell stack, a hydrogen supply subsystem, an air supply subsystem, and an exhaust gas treatment subsystem; wherein, the hydrogen-air fuel cell stack includes: a hydrogen inlet, an air inlet, and a hydrogen outlet and an air outlet.

[0007] The hydrogen supply subsystem is connected to the hydrogen-air fuel cell stack via a hydrogen inlet and is used to supply hydrogen to the hydrogen-air fuel cell stack.

[0008] The air supply subsystem is connected to the hydrogen-air fuel cell stack via an air inlet and is used to supply air to the hydrogen-air fuel cell stack.

[0009] The hydrogen-air fuel cell stack is used to carry out electrochemical reactions based on hydrogen supplied by a hydrogen supply subsystem and air supplied by an air supply subsystem.

[0010] The exhaust gas treatment subsystem is connected to the hydrogen-air fuel cell stack via the hydrogen outlet and air outlet, and is used to treat the exhaust gas generated after the reaction of the hydrogen-air fuel cell stack.

[0011] In the aforementioned fuel cell hydrogen-air pressure automatic following control system, the hydrogen supply subsystem includes: a high-pressure hydrogen cylinder, a hydrogen medium-pressure solenoid valve, a first-stage pressure reducing valve, a hydrogen supply and return assembly, and a pressure following valve connected in sequence.

[0012] High-pressure hydrogen cylinders are used to provide a hydrogen source;

[0013] Hydrogen medium-pressure solenoid valve, used to control the supply and cut-off of hydrogen;

[0014] The first-stage pressure reducing valve is used to regulate the hydrogen pressure output from the high-pressure hydrogen cylinder to keep it constant, thus maintaining a constant pressure of the working fluid in the hydrogen supply and return assembly.

[0015] The hydrogen supply and return assembly is used to regulate the hydrogen to the appropriate pressure to ensure the hydrogen supply to the hydrogen-air fuel cell stack;

[0016] The pressure follower valve is used to compare the hydrogen-air pressure difference and, according to the set pressure difference, achieve rapid adaptive following of hydrogen pressure to air pressure under all operating conditions.

[0017] In the aforementioned fuel cell hydrogen-air pressure automatic following control system, the pressure following valve includes: an adjusting screw, an upper housing, an adjusting spring, a feedback port, a diaphragm, a lower housing, an air inlet, an air outlet, a control chamber, a valve seat, a valve core, and a feedback chamber.

[0018] The upper housing is mounted on the lower housing, and a valve core is provided between the upper housing and the lower housing;

[0019] The diaphragm is fixed to the valve core; wherein, the upper end face of the diaphragm forms a feedback cavity with the upper housing, and the feedback cavity extends longitudinally inside the upper housing; the lower end face of the diaphragm forms a control cavity with the lower housing, and the control cavity extends longitudinally inside the lower housing.

[0020] The feedback chamber has a feedback port on its side, and the control chamber has an air inlet and an air outlet on its side.

[0021] An adjusting spring is positioned between the valve core and the upper housing and can move longitudinally within the feedback chamber. One end of the adjusting spring is connected to an adjusting screw, and the other end is connected to the valve core. The adjusting screw is installed at the center of the top of the upper housing, allowing adjustment of the spring compression.

[0022] The valve seat is located inside the control chamber and fixed on the lower housing; a through hole is opened at the center of the valve seat, which is connected to the air outlet.

[0023] In the aforementioned fuel cell hydrogen-air pressure automatic following control system, the air supply subsystem includes: an air filter, an air compressor, an air intercooler, and an air inlet throttle valve connected in sequence.

[0024] Air filters are used to filter impurities in the air and ensure the quality of the air entering the hydrogen-air fuel cell stack.

[0025] An air compressor is used to pressurize filtered air.

[0026] An air intercooler is used to cool down the pressurized, high-temperature air to ensure that the temperature of the air entering the hydrogen-air fuel cell stack meets the requirements. One output of the air intercooler is connected to the air inlet throttle valve, and the other output is connected to the feedback port of the pressure follower valve.

[0027] The air inlet throttle valve is used to open or close the air passage and regulate the airflow by adjusting its opening degree.

[0028] In the aforementioned fuel cell hydrogen-air pressure automatic following control system, hydrogen supplied by the hydrogen supply subsystem enters the control chamber of the pressure following valve through the air inlet, and air supplied by the air supply subsystem enters the feedback chamber of the pressure following valve through the feedback port. The pressure following valve is used to supply hydrogen to the hydrogen-air fuel cell stack when the pressure of the hydrogen in the control chamber is adjusted to meet a certain pressure difference with the air pressure in the feedback chamber.

[0029] In the aforementioned fuel cell hydrogen-air pressure automatic following control system, when the force exerted by hydrogen on the diaphragm in the control chamber is less than the sum of the force exerted by air on the diaphragm in the feedback chamber and the force exerted by the adjusting spring on the diaphragm, the pressure following valve closes, the inlet hydrogen pressure increases, and the control chamber pressure increases accordingly. This continues until the hydrogen pressure in the control chamber exceeds the sum of the force exerted by air on the diaphragm in the feedback chamber and the force exerted by the adjusting spring on the diaphragm, at which point the pressure following valve opens, and the hydrogen path is connected. As the pressure following valve opens, the inlet hydrogen pressure decreases, and the pressure following valve tends to close until the pressure difference between the hydrogen pressure in the control chamber and the air pressure in the feedback chamber tends to stabilize.

[0030] In the aforementioned fuel cell hydrogen-air pressure automatic tracking control system, the design pressure of the air inlet is 1.6–2.2 MPa.

[0031] In the aforementioned fuel cell hydrogen-air pressure automatic following control system, under the regulation and control of the pressure following valve, the hydrogen inlet pressure is always 0.1 to 0.3 MPa higher than the air inlet design pressure.

[0032] In the aforementioned fuel cell hydrogen-air pressure automatic following control system, when the pressure difference between hydrogen and air is higher than the set value, the opening of the pressure following valve increases, and when the pressure difference between hydrogen and air is lower than the set value, the opening of the pressure following valve decreases, thus stabilizing the hydrogen-air pressure difference within the set range; and the hydrogen pressure is consistently higher than the air pressure to reduce gas permeation from the air path to the hydrogen path, thereby protecting the hydrogen-air fuel cell stack.

[0033] In the aforementioned fuel cell hydrogen-air pressure automatic following control system, the exhaust gas treatment subsystem includes: a hydrogen-water separator, an air outlet throttle valve, and a gas mixing chamber; wherein, the air outlet is connected to the gas mixing chamber through the air outlet throttle valve, and the hydrogen outlet is connected to the gas mixing chamber through the hydrogen-water separator.

[0034] The hydrogen-water separator is used to separate the liquid water and gas carried at the outlet of the hydrogen-air fuel cell stack. The hydrogen can be recirculated and re-enter the stack inlet. At the same time, the hydrogen is periodically pulsed and discharged into the gas mixing chamber to ensure the purity of the hydrogen.

[0035] The air outlet throttle valve is used to regulate the air pressure inside the hydrogen-air fuel cell stack.

[0036] The gas mixing chamber is used to mix and dilute unreacted hydrogen with air before releasing it into the outside.

[0037] The present invention has the following advantages:

[0038] (1) This invention discloses a control system for automatic hydrogen-air pressure following of fuel cell, which can control the hydrogen-air pressure difference within the range allowed by the fuel cell, thus avoiding damage to the membrane electrode assembly due to excessive pressure difference.

[0039] (2) This invention discloses a control system for automatic hydrogen-air pressure following in fuel cells. It achieves automatic following of hydrogen-air pressure difference in fuel cells through mechanical control, avoiding pressure runaway caused by faults in electronic control and other systems, while reducing auxiliary system consumption.

[0040] (3) This invention discloses a control system for automatic hydrogen-air pressure following of fuel cells. When the outlet pressure of the pressure following valve increases, the hydrogen-air pressure difference will decrease, which is more suitable for the pressure difference control requirements of hydrogen-air fuel cell systems. Attached Figure Description

[0041] Figure 1 This is a structural block diagram of a fuel cell hydrogen-air pressure automatic following control system according to an embodiment of the present invention;

[0042] Figure 2 This is a schematic diagram of the structure of a pressure follower valve in an embodiment of the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments disclosed in the present invention will be described in further detail below with reference to the accompanying drawings.

[0044] like Figure 1 In this embodiment, the control system for automatic hydrogen-air pressure following of the fuel cell includes: hydrogen-air fuel cell stack 1, hydrogen supply subsystem 2, air supply subsystem 3, and exhaust gas treatment subsystem 4.

[0045] In this embodiment, the hydrogen-air fuel cell stack 1 may specifically include: a hydrogen inlet 101, an air inlet 102, a hydrogen outlet 103, and an air outlet 104. Specifically, the hydrogen supply subsystem 2 is connected to the hydrogen-air fuel cell stack 1 via the hydrogen inlet 101 and is used to supply hydrogen to the hydrogen-air fuel cell stack 1; the air supply subsystem 3 is connected to the hydrogen-air fuel cell stack 1 via the air inlet 102 and is used to supply air to the hydrogen-air fuel cell stack 1; the hydrogen-air fuel cell stack 1 is used to perform an electrochemical reaction based on the hydrogen supplied by the hydrogen supply subsystem 2 and the air supplied by the air supply subsystem 3; and the exhaust gas treatment subsystem 4 is connected to the hydrogen-air fuel cell stack 1 via the hydrogen outlet 103 and the air outlet 104 and is used to treat the exhaust gas generated after the reaction in the hydrogen-air fuel cell stack 1.

[0046] In this embodiment, the hydrogen supply subsystem 2 may specifically include: a high-pressure hydrogen cylinder 201, a medium-pressure hydrogen solenoid valve 202, a first-stage pressure reducing valve 203, a hydrogen supply and return assembly 204, and a pressure follower valve 205 connected in sequence. The high-pressure hydrogen cylinder 201 provides a hydrogen source; the medium-pressure hydrogen solenoid valve 202 controls the supply and cutoff of hydrogen; the first-stage pressure reducing valve 203 regulates the gas source pressure to maintain a constant pressure of the working fluid in the hydrogen supply and return assembly 204; the hydrogen supply and return assembly 204 adjusts the high-pressure hydrogen to an appropriate pressure to ensure the hydrogen supply to the hydrogen-air fuel cell stack; and the pressure follower valve 205, connected in series after the hydrogen supply and return assembly 204, enables hydrogen-air pressure following, comparing the inlet hydrogen-air pressure of the hydrogen-air fuel cell stack 1 with the set pressure difference to achieve rapid adaptive following of hydrogen pressure to air pressure under all operating conditions.

[0047] In this embodiment, as Figure 2The pressure follower valve 205 may specifically include: an adjusting screw 2051, an upper housing 2052, an adjusting spring 2053, a feedback port 2054, a diaphragm 2055, a lower housing 2056, an air inlet 2057, an air outlet 2058, a control chamber 2059, a valve seat 20510, a valve core 20511, and a feedback chamber 20512. The upper housing 2052 is mounted on the lower housing 2056, and the valve core 20511 is disposed between the upper housing 2052 and the lower housing 2056. A diaphragm 2055 is fixed to a valve core 20511. A feedback chamber 20512 is formed between the upper end face of the diaphragm 2055 and the upper housing 2052, and the feedback chamber 20512 extends longitudinally inside the upper housing 2052. A control chamber 2059 is formed between the lower end face of the diaphragm 2055 and the lower housing 2056, and the control chamber 2059 extends longitudinally inside the lower housing 2056. A feedback port 2054 is provided on the side of the feedback chamber 20512, and an air inlet 2057 and an air outlet 2058 are provided on the side of the control chamber 2059. An adjusting spring 2053 is disposed between the valve core 20511 and the upper housing 2052, and can move longitudinally within the feedback chamber 20512. One end of the adjusting spring 2053 is connected to the adjusting screw 2051, and the other end is connected to the valve core 20511. The adjusting screw 2051 is installed at the center of the top of the upper housing 2052, which allows for adjustment of the compression of the adjusting spring 2053. The valve seat 20510 is located within the control chamber 2059 and fixed to the lower housing 2056. The valve seat 20510 has a through hole at its center, which communicates with the air outlet 2058.

[0048] In this embodiment, the air supply subsystem 3 may specifically include: an air filter 301, an air compressor 302, an air intercooler 303, and an air inlet throttle valve 304 connected in sequence. The air filter 301 filters impurities from the air to ensure the air quality entering the hydrogen-air fuel cell stack 1; the air compressor 302 pressurizes the filtered air; the air intercooler 303 cools the pressurized, high-temperature air to ensure the temperature of the air entering the hydrogen-air fuel cell stack 1 meets requirements; and the air inlet throttle valve 304 controls the opening and closing of the air path and regulates the flow rate by adjusting its opening. One output of the air intercooler 303 is connected to the air inlet throttle valve 304, and the other output is connected to the feedback port 2054 of the pressure follower valve 205.

[0049] Preferably, hydrogen supplied by hydrogen supply subsystem 2 enters the control chamber 2059 of pressure follower valve 205 through inlet 2057, and air supplied by air supply subsystem 3 enters the feedback chamber 20512 of pressure follower valve 205 through feedback port 2054. Pressure follower valve 205 is used to supply hydrogen to hydrogen-air fuel cell stack 1 when the pressure of hydrogen in control chamber 2059 is adjusted to meet a certain pressure difference with the air pressure in feedback chamber 20512. When the pressure difference between hydrogen and air is higher than a set value, the opening of pressure follower valve 205 increases; when the pressure difference is lower than the set value, the opening of pressure follower valve 205 decreases, stabilizing the hydrogen-air pressure difference within the set range. Furthermore, the hydrogen pressure is consistently higher than the air pressure to reduce gas permeation from the air path to the hydrogen path, thus protecting hydrogen-air fuel cell stack 1.

[0050] Preferably, when the force of hydrogen gas in the control chamber 2059 acting on the diaphragm 2055 is less than the sum of the force of air in the feedback chamber 20512 acting on the diaphragm 2055 and the force of adjusting spring 2053 acting on the diaphragm 2055, the pressure follower valve 205 closes, the hydrogen pressure at the inlet 2057 increases, and the pressure in the control chamber 2059 increases accordingly, until the hydrogen pressure in the control chamber 2059 exceeds the sum of the force of air in the feedback chamber 20512 acting on the diaphragm 2055 and the force of adjusting spring 2053 acting on the diaphragm 2055. Then, the pressure follower valve 205 opens, and the hydrogen path is connected. As the pressure follower valve 205 opens, the hydrogen pressure at the inlet 2057 decreases, and the pressure follower valve 205 tends to close, until the pressure difference between the hydrogen pressure in the control chamber 2059 and the air pressure in the feedback chamber 20512 reaches a stable level.

[0051] In this embodiment, the design pressure of air inlet 102 is 1.6–2.2 MPa. Under the regulation and control of pressure follower valve 205, the pressure of hydrogen inlet 101 is always 0.1–0.3 MPa higher than the design pressure of air inlet 102.

[0052] In this embodiment, the exhaust gas treatment subsystem 4 may specifically include: a hydrogen-water separator 401, an air outlet throttle valve 402, and a gas mixing chamber 403. The air outlet 104 is connected to the gas mixing chamber 403 via the air outlet throttle valve 402, and the hydrogen outlet 103 is connected to the gas mixing chamber 403 via the hydrogen-water separator 401. The hydrogen-water separator 401 separates the liquid water and gas carried at the outlet of the hydrogen-air fuel cell stack 1, allowing hydrogen to re-enter the stack inlet through circulation. Simultaneously, hydrogen is periodically pulsed and discharged into the gas mixing chamber 403 to ensure hydrogen purity. The air outlet throttle valve 402 regulates the air pressure inside the hydrogen-air fuel cell stack 1. The gas mixing chamber 403 dilutes unreacted hydrogen with air before discharging it to the outside.

[0053] In this embodiment, as Figure 2 The specific structure and working principle of the pressure follower valve 205 are described in detail below. As mentioned earlier, the control chamber 2059 and the feedback chamber 20512 are separated into two independent closed chambers by a diaphragm 2055 and a valve core 20511. The feedback port 2054 is connected to the air intercooler 303 to introduce air into the feedback chamber 20512; the air inlet 2057 is connected to the hydrogen supply and return assembly 204 to introduce hydrogen into the control chamber 2059. The air and hydrogen in the feedback chamber 20512 and control chamber 2059 exert pressure on the diaphragm 2055. When the forces exerted by the air in the feedback chamber 20512 on the diaphragm 2055, the forces exerted by the hydrogen in the control chamber 2059 on the diaphragm 2055, and the forces exerted by the adjusting spring 2053 on the diaphragm 2055 reach equilibrium, the relative position of the valve core 20511 and the valve seat 20510 is determined. The relative position of the valve core 20511 and the valve seat 20510 is used to indicate the magnitude of the hydrogen-air pressure difference ΔP. When the pressure difference between the air and hydrogen in the feedback chamber 20512 and control chamber 2059 changes, the force balance is disrupted. The adjusting spring 2053 drives the valve core 20511 to move, changing the resistance coefficient of the pressure follower valve and controlling the pressure difference between the two media to always remain at the set pressure difference value.

[0054] Preferably, when the sum of the force exerted by the air in the feedback chamber 20512 on the diaphragm 2055 and the force exerted by the adjusting spring 2053 on the diaphragm 2055 is greater than the force exerted by the hydrogen in the control chamber 2059 on the diaphragm 2055, the pressure follower valve closes. As the pressure follower valve closes, the pressure of the hydrogen in the control chamber 2059 increases until the force exerted by the hydrogen in the control chamber 2059 on the diaphragm 2055 is greater than the sum of the force exerted by the air in the feedback chamber 20512 on the diaphragm 2055 and the force exerted by the adjusting spring 2053 on the diaphragm 2055, at which point the pressure follower valve opens. As the pressure follower valve opens, the pressure of the hydrogen in the control chamber 2059 decreases, and the pressure follower valve gradually tends to close until the hydrogen gas is in a state of pressure differential equilibrium.

[0055] Furthermore, a longitudinally extending guide groove is provided on the inner wall of the feedback cavity 20512, and the edge of the diaphragm 2055 is slidably disposed in the guide groove; wherein, the guide groove plays a longitudinal guiding role for the diaphragm 2055, so that the diaphragm 2055 will not deviate during the sliding process.

[0056] The preset hydrogen-air pressure differential value can be adjusted and controlled by adjusting the pre-compression of the adjusting spring 2053. Specifically, by adjusting the tightness of the adjusting screw 2051, the pre-compression of the adjusting spring 2053 is adjusted, thereby adjusting the set pressure differential value. A larger pre-compression of the adjusting spring 2053 results in a greater force exerted by the spring 2053 on the diaphragm 2055, making the diaphragm 2055 less prone to longitudinal movement; conversely, a smaller pre-compression of the adjusting spring 2053 results in a smaller force exerted by the spring 2053 on the diaphragm 2055, making the diaphragm 2055 more prone to longitudinal movement.

[0057] Based on the above embodiments, the operation steps of the control system for automatic hydrogen-air pressure following of the fuel cell are described below:

[0058] a) The operating characteristics of the hydrogen-air fuel cell stack are adjusted by changing the pre-compression of the regulating spring in the pressure follower valve to set the hydrogen-air pressure differential within a suitable range.

[0059] b) When the hydrogen-air fuel cell starts working, the hydrogen medium-pressure solenoid valve and the first-stage pressure reducing valve open, and the hydrogen supply and return assembly adjusts the hydrogen pressure to a suitable range. The hydrogen is then supplied to the hydrogen inlet of the hydrogen-air fuel cell stack through the control chamber of the pressure follower valve.

[0060] c) After being filtered, compressed, and cooled by the air supply subsystem, outside air is supplied to the air inlet of the hydrogen-air fuel cell stack in one path and enters the feedback chamber of the pressure follower valve in another path.

[0061] d) Under the regulation of the pressure follower valve, the hydrogen-side inlet pressure of the hydrogen-air fuel cell stack is always 0.1–0.3 MPa higher than the air-side inlet pressure to reduce gas permeation from the air path to the hydrogen path, thus protecting the stack. Specifically, when the pressure difference is higher than the set value, the opening of the pressure follower valve increases, and the inlet pressure decreases; when the pressure difference is lower than the set value, the opening of the pressure follower valve decreases, and the inlet pressure increases.

[0062] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

[0063] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A control system for automatic following of hydrogen air pressure of a fuel cell, characterized by, The system comprises a hydrogen-air fuel cell stack, a hydrogen supply subsystem, an air supply subsystem and a tail gas treatment subsystem; wherein the hydrogen-air fuel cell stack comprises a hydrogen inlet, an air inlet, a hydrogen outlet and an air outlet; The hydrogen supply subsystem is communicated with the hydrogen-air fuel cell stack through the hydrogen inlet; wherein the hydrogen supply subsystem comprises a high-pressure hydrogen cylinder, a hydrogen medium-pressure electromagnetic valve, a primary pressure reducing valve, a hydrogen supply and return assembly and a pressure following valve connected in sequence; The air supply subsystem is communicated with the hydrogen-air fuel cell stack through the air inlet; wherein the air supply subsystem comprises an air filter, an air compressor, an air intermediate cooler and an air inlet throttle valve connected in sequence; wherein one output of the air intermediate cooler is connected to the air inlet throttle valve, and the other output is connected to a feedback port of the pressure following valve to enter the pressure following valve; The tail gas treatment subsystem is communicated with the hydrogen-air fuel cell stack through the hydrogen outlet and the air outlet; The pressure following valve comprises an adjusting screw, an upper housing, an adjusting spring, a feedback port, a diaphragm, a lower housing, an air inlet port, an air outlet port, a control cavity, a valve seat, a valve core and a feedback cavity; wherein the upper housing is mounted on the lower housing, and the valve core is arranged between the upper housing and the lower housing; the diaphragm is fixed on the valve core; the feedback cavity is formed between the upper end surface of the diaphragm and the upper housing and extends longitudinally in the upper housing; the control cavity is formed between the lower end surface of the diaphragm and the lower housing and extends longitudinally in the lower housing; the feedback port is arranged on the side surface of the feedback cavity, and the air inlet port and the air outlet port are arranged on the side surface of the control cavity; the adjusting spring is arranged between the valve core and the upper housing and can move longitudinally in the feedback cavity; one end of the adjusting spring is connected to the adjusting screw, and the other end is connected to the valve core; the adjusting screw is mounted at the center of the top of the upper housing and can adjust the compression amount of the adjusting spring; the valve seat is arranged in the control cavity and is fixed on the lower housing; a through hole is formed in the center of the valve seat and is communicated with the air outlet port; The hydrogen provided by the hydrogen supply subsystem enters the control cavity of the pressure following valve through the air inlet port, and the air provided by the air supply subsystem enters the feedback cavity of the pressure following valve through the feedback port; Under the adjusting control of the pressure following valve, the pressure of the hydrogen inlet is always 0.1-0.3 MPa higher than the design pressure of the air inlet. When the force of the hydrogen in the control cavity acting on the diaphragm is less than the sum of the force of the air in the feedback cavity acting on the diaphragm and the force of the adjusting spring acting on the diaphragm, the pressure following valve is closed, the hydrogen pressure of the air inlet port is increased, the pressure of the control cavity is increased, and when the hydrogen pressure in the control cavity is greater than the sum of the force of the air in the feedback cavity acting on the diaphragm and the force of the adjusting spring acting on the diaphragm, the pressure following valve is opened, and the hydrogen path is communicated; with the opening of the pressure following valve, the hydrogen pressure of the air inlet port is reduced, the pressure following valve tends to be closed, and the pressure difference between the hydrogen pressure in the control cavity and the air pressure in the feedback cavity tends to be stable.

2. The control system for fuel cell hydrogen air pressure automatic following according to claim 1, characterized in that, The design pressure of the air inlet is 1.6-2.2 MPa.

3. The control system for fuel cell hydrogen air pressure automatic following according to claim 1, characterized in that, ​ 4. The control system for fuel cell hydrogen air pressure automatic following according to claim 1, characterized in that, When the pressure difference between hydrogen and air is higher than the set value, the pressure following valve opening degree becomes larger, and when the pressure difference between hydrogen and air is lower than the set value, the pressure following valve opening degree becomes smaller, so that the hydrogen-air pressure difference is stabilized within the set range; and the hydrogen pressure is higher than the air pressure, so as to reduce the air permeation to the hydrogen path, and to protect the hydrogen-air fuel cell stack.

5. The control system for fuel cell hydrogen air pressure automatic following according to claim 1, characterized in that, The tail gas treatment subsystem comprises a hydrogen water separator, an air outlet throttle valve and a gas mixing chamber; wherein the air outlet is connected to the gas mixing chamber through the air outlet throttle valve, and the hydrogen outlet is connected to the gas mixing chamber through the hydrogen water separator; the hydrogen water separator is used to separate the liquid water and gas carried by the hydrogen-air fuel cell stack outlet, and the hydrogen can re-enter the stack inlet through circulation, and the hydrogen is periodically pulsed to the gas mixing chamber for emission, so as to ensure the hydrogen purity; the air outlet throttle valve is used to adjust the air pressure inside the hydrogen-air fuel cell stack; and the gas mixing chamber is used to dilute and discharge the hydrogen not participating in the reaction to the outside after mixing with air.

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