Fuel cell stack electrode side exhaust structure, fuel cell system, and exhaust method thereof

Abstract

The application provides a fuel cell stack electrode side exhaust structure, a fuel cell system and an exhaust method thereof. The fuel cell stack comprises a cathode side, which is provided with an air compressor, a three-way valve, a humidifier and a tail exhaust valve. The inlet of the air compressor is connected to the atmosphere, and the outlet is connected to the inlet of the three-way valve. The first outlet of the three-way valve is connected to the first inlet of the humidifier, and the second outlet is connected to the first inlet of the tail exhaust valve. The first outlet of the humidifier is connected to the cathode inlet of the fuel cell stack, the cathode outlet of the fuel cell stack is connected to the second inlet of the humidifier, the second outlet of the humidifier is connected to the second inlet of the tail exhaust valve, and the outlet of the tail exhaust valve is connected to the atmosphere. The exhaust structure is arranged on the cathode side and comprises a pressure sensor, a positive disengaging pump and a controller. The pressure sensor and the positive disengaging pump are arranged on the pipeline between the first outlet of the three-way valve and the cathode inlet, and are both in communication connection with the controller. The application can reduce the air content of the cathode side and greatly reduce the pressure maintaining time.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, specifically to a fuel cell stack electrode-side exhaust structure, a fuel cell system, and an exhaust method thereof. Background Technology

[0002] In recent years, as fuel cell engines have gradually moved towards commercial application, improving their stability and durability has become a key focus of research and development, placing higher demands on the air intake system. If residual air remains at the cathode after the fuel cell is shut down, the oxygen within will permeate through the proton exchange membrane (PEM) and gradually enter the anode. This can lead to the formation of a hydrogen-air interface at the anode upon startup, generating a high overpotential, degrading the catalyst carbon support in the PEM, and causing catalyst loss, resulting in a decrease in stack performance and durability. To avoid this situation, it is necessary to seal the cathode circuit of the fuel cell stack to prevent air ingress, and simultaneously consume any residual oxygen at the cathode before shutdown to create an oxygen-free environment.

[0003] Currently, after a fuel cell is sealed, a certain amount of air-hydrogen needs to be supplied to maintain pressure inside the fuel cell, consuming the oxygen in the air on the cathode side. This process affects the shutdown time and also consumes a certain amount of hydrogen. Each shutdown involves a pressure-maintaining process: after shutdown, normal pressure is maintained, and hydrogen is introduced to consume the oxygen in the sealed cavity on the cathode side. This pressure-maintaining process consumes all the oxygen in the sealed cavity, which is relatively large, requiring a long time and consuming a significant amount of hydrogen. Therefore, reducing the pressure-maintaining time after fuel cell shutdown and minimizing hydrogen consumption is an urgent problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a fuel cell stack electrode side exhaust structure, fuel cell system and exhaust method, which can reduce the air content on the cathode side of the fuel cell stack and reduce the pressure holding time.

[0005] To achieve the above objectives, the following technical solution is provided:

[0006] This invention provides an electrode-side exhaust structure for a fuel cell stack. The fuel cell stack includes a cathode side, which is equipped with an air compressor, a three-way valve, a humidifier, and a tailpipe valve. The air compressor's inlet is connected to the atmosphere, and its outlet is connected to the inlet of the three-way valve. The first outlet of the three-way valve is connected to the first inlet of the humidifier, and its second outlet is connected to the first inlet of the tailpipe valve. The first outlet of the humidifier is connected to the cathode inlet of the fuel cell stack, and the cathode outlet of the fuel cell stack is connected to the second inlet of the humidifier. The second outlet of the humidifier is connected to the second inlet of the tailpipe valve, and the outlet of the tailpipe valve is connected to the atmosphere.

[0007] The exhaust structure on the electrode side of the fuel cell stack is located on the cathode side and includes a pressure sensor, an active disconnect pump, and a controller. The pressure sensor and the active disconnect pump are located on the pipeline between the first outlet of the three-way valve and the cathode inlet, and are both communicatively connected to the controller.

[0008] Optionally, the inlet of the active disconnect pump is connected to the first outlet of the humidifier, and the outlet is connected to the cathode inlet of the fuel cell stack.

[0009] Optionally, the detection end of the pressure sensor is connected to the pipeline between the first outlet of the humidifier and the inlet of the active disconnect pump.

[0010] Optionally, an air filter is also provided on the cathode side, with the inlet of the air filter connected to the atmosphere and the outlet connected to the air compressor inlet.

[0011] Optionally, a flow meter is also provided on the cathode side, with the inlet of the flow meter connected to the outlet of the air filter and the outlet connected to the inlet of the air compressor.

[0012] Optionally, the flow meter also has a monitoring point for detecting ambient humidity.

[0013] Optionally, an intercooler is further provided on the cathode side, the inlet of which is connected to the outlet of the air compressor, and the outlet is connected to the inlet of the three-way valve; and / or

[0014] The cathode side is also provided with a tailpipe throttle valve, the inlet of which is connected to the second outlet of the humidifier and the outlet is connected to the second inlet of the tailpipe valve.

[0015] Optionally, the three-way valve is an electrically controlled three-way valve, and the electrically controlled three-way valve is communicatively connected to the controller.

[0016] The present invention also provides a fuel cell system, including the fuel cell stack electrode-side exhaust structure described in any of the above technical solutions.

[0017] The present invention also provides a method for venting the fuel cell stack electrode side venting structure as described in any of the above technical solutions, comprising the following steps:

[0018] S100, fuel cell engine purging complete, three-way valve and tailpipe valve closed;

[0019] S200, Set the target pressure value inside the fuel cell stack;

[0020] S300, Adjust the speed of the active disconnect pump;

[0021] S400: The pressure sensor monitors whether the pressure value inside the fuel cell stack has reached the set target pressure value. If yes, proceed to S500; otherwise, return to S300.

[0022] S500, shut down the active disconnect pump;

[0023] S600, End.

[0024] Compared with existing technologies, the fuel cell stack electrode-side exhaust structure, fuel cell system, and exhaust method provided by this invention add an active disconnect pump (APP) between two sealed valves, a three-way valve and a tailpipe valve, on the cathode side of the fuel cell stack. A pressure sensor identifies the internal pressure of the chamber, controlling the opening time and exhaust speed of the APP valve. After the fuel cell engine purging is completed and the tailpipe valve and three-way valve are closed, a target pressure value is set inside the stack. Then, the speed of the active disconnect pump is adjusted to exhaust air from the stack. The operation of the active disconnect pump is controlled by monitoring the internal pressure value through a pressure sensor. When the internal pressure reaches the target pressure value, the active disconnect pump is shut off, ending the operation. This invention adds an active disconnect pump (APP) to the sealed cavity on the cathode side of the fuel cell stack. After shutdown, the active disconnect pump is activated to expel the air inside the sealed cavity on the cathode side. For example, if the original sealed cavity has a volume of 10L under normal pressure, the active disconnect pump can expel 5L of air from the sealed cavity. This can reduce the pressure holding time by 50% and the hydrogen consumption during pressure holding by 50%, greatly reducing the pressure holding time, reducing hydrogen consumption, saving resources, and improving shutdown efficiency.

[0025] The summary section is provided to present the chosen concepts in a simplified form, which will be further described in the detailed description below. The summary section is not intended to identify essential or necessary features of this disclosure, nor is it intended to limit the scope of this disclosure. Attached Figure Description

[0026] The above and other objects, features and advantages of this disclosure will become more apparent from the accompanying drawings, in which like reference numerals generally denote like parts.

[0027] Figure 1 A schematic diagram of the structure of a fuel cell system according to an embodiment of the present invention is shown;

[0028] Figure 2 A control flowchart of the exhaust method for the exhaust structure of the fuel cell stack electrode side according to an embodiment of the present invention is shown.

[0029] Figure label:

[0030] 100-Fuel cell engine; 101-Fuel cell stack; 102-Cathode side; 103-Air filter; 104-Flow meter; 105-Air compressor; 106-Intercooler; 107-Three-way valve; 108-Humidifier; 109-Pressure sensor; 110-Active disconnect pump; 111-Exhaust throttle valve; 112-Exhaust valve. Detailed Implementation

[0031] Embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0032] The term "comprising" and its variations as used herein signify open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "at least partially based on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0033] like Figure 1 As shown, this embodiment provides an electrode-side exhaust structure for a fuel cell stack. The fuel cell stack 101 includes an anode side and a cathode side. The fuel cell stack electrode-side exhaust structure is disposed on the cathode side of the fuel cell stack 101 of the fuel cell engine 100, and includes an air compressor 105, a three-way valve 107, a humidifier 108, and a tailpipe valve 112. The inlet of the air compressor 105 is connected to the atmosphere, and the outlet is connected to the inlet of the three-way valve 107. The first outlet of the three-way valve 107 is connected to the first inlet of the humidifier 108, and the second outlet is connected to the first inlet of the tailpipe valve 112. The first outlet of the humidifier 108 is connected to the cathode inlet of the fuel cell stack 101, the cathode outlet of the fuel cell stack 101 is connected to the second inlet of the humidifier 108, the second outlet of the humidifier 108 is connected to the second inlet of the exhaust valve 112, and the outlet of the exhaust valve 112 is connected to the atmosphere. A pressure sensor 109 and an active disconnect pump 110 are also installed on the pipeline between the first outlet of the three-way valve 107 and the cathode inlet of the fuel cell stack 101. The fuel cell stack 101 also includes a controller, and the pressure sensor 109 and the active disconnect pump 110 are both communicatively connected to the controller.

[0034] Preferably, in this embodiment, the inlet of the active disconnect pump 110 is connected to the first outlet of the humidifier 108, and the outlet is connected to the cathode inlet of the fuel cell stack 101. The active disconnect pump 110 can start rotating after the fuel cell engine 100 stops purging, so as to discharge the air in the sealed cavity on the cathode side of the fuel cell stack 101 and reduce the air volume in the sealed cavity.

[0035] Optionally, the detection end of the pressure sensor 109 is connected to the pipeline between the first outlet of the humidifier 108 and the inlet of the active disconnect pump 110, which can accurately detect the air pressure value in the sealed cavity on the cathode side of the fuel cell stack 101, and transmit the signal to the controller to control the speed of the active disconnect pump 110.

[0036] Furthermore, in order to ensure the purity of the air entering the fuel cell stack 101 and guarantee the operational safety of the fuel cell stack 101, an air filter 103 is also provided on the cathode side. The inlet of the air filter 103 is connected to the atmosphere, and the outlet is connected to the inlet of the air compressor 105. The air filter 103 is located on the front side of the air compressor 105, which can more directly filter the purity of the air entering the air compressor 105.

[0037] Optionally, a flow meter 104 is also provided on the cathode side. The inlet of the flow meter 104 is connected to the outlet of the air filter 103, and the outlet is connected to the inlet of the air compressor 105. The flow meter 104 ensures that the flow rate of air entering the fuel cell stack 101 per unit time is appropriate, ensuring that the air intake of the fuel cell stack 101 meets the requirements without causing overload or safety issues. Preferably, since the ratio of hydrogen to oxygen required for the reaction in the fuel cell stack 101 is related to the air humidity, the flow meter 104 also has a monitoring point for detecting the ambient humidity. This satisfies the functional requirements and has a simple and centralized structure.

[0038] Preferably, since the reaction of hydrogen and air in the fuel cell stack 101 requires a specific temperature, an intercooler 106 is also provided on the cathode side. The inlet of the intercooler 106 is connected to the outlet of the air compressor 105, and the outlet is connected to the inlet of the three-way valve 107. It is used to cool down the air after the air compressor 105 has compressed and heated up, so as to ensure that the air enters the fuel cell stack 101 at a suitable temperature.

[0039] Furthermore, a tailpipe throttle valve 111 is also provided on the cathode side. The inlet of the tailpipe throttle valve 111 is connected to the second outlet of the humidifier 108, and the outlet is connected to the second inlet of the tailpipe valve 112. The tailpipe throttle valve 111 can precisely control the opening degree of the reaction gas flowing from the second outlet of the humidifier 108 to the tailpipe valve 112.

[0040] Optionally, the three-way valve 107 is an electrically controlled three-way valve, which is connected in communication with the controller and can automatically and accurately control whether air flows to the fuel cell stack 101.

[0041] This embodiment also provides a fuel cell system, including a fuel cell engine 100, a fuel cell stack 101, and the above-mentioned fuel cell stack electrode-side exhaust structure.

[0042] refer to Figure 2 This embodiment also provides a method for venting the above-mentioned fuel cell stack electrode-side venting structure, including the following steps:

[0043] S100 and fuel cell engine 100 purging is completed, and three-way valve 107 and tail exhaust valve 112 are closed;

[0044] S200, Set the target pressure value inside the fuel cell stack 101;

[0045] S300, Adjust the speed of the active disconnect pump 110;

[0046] S400: Pressure sensor 109 monitors whether the pressure value inside fuel cell stack 101 has reached the set target pressure value. If yes, proceed to S500; otherwise, return to S300.

[0047] S500, shut down the active disconnect pump 110;

[0048] S600, End.

[0049] Compared with the prior art, the fuel cell stack electrode-side exhaust structure and exhaust method provided in this embodiment add an active disconnect pump 110 (APP) between two sealed valves, a three-way valve 107 and a tailpipe valve 112, on the cathode side of the fuel cell stack 101. A pressure sensor 109 identifies the internal pressure of the chamber and controls the opening time and exhaust speed of the APP valve. After the fuel cell engine 100 is purged and the tailpipe valve 112 and three-way valve 107 are closed, a target pressure value is set inside the stack. Then, the speed of the active disconnect pump 110 is adjusted to exhaust air from the stack. The pressure sensor 109 monitors the internal pressure value to control the operation of the active disconnect pump 110. When the internal pressure reaches the target pressure value, the active disconnect pump 110 is shut off, ending the operation. This invention adds an active disconnect pump 110 (APP) to the cathode-side sealed cavity of the fuel cell stack 101. After shutdown, the active disconnect pump 110 is activated to discharge the air inside the cathode-side sealed cavity. For example, if the original sealed cavity has a volume of 10L under normal pressure, the active disconnect pump 110 discharges 5L of air from the sealed cavity. This reduces the pressure holding time by 50% and the pressure holding hydrogen consumption by 50%, greatly reducing the pressure holding time, reducing hydrogen consumption, saving resources, and improving shutdown efficiency.

[0050] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A fuel cell stack electrode-side exhaust structure, wherein the fuel cell stack (101) includes a cathode side, wherein an air compressor (105), a three-way valve (107), a humidifier (108), and a tailpipe valve (112) are provided on the cathode side, wherein the inlet of the air compressor (105) is connected to the atmosphere and the outlet is connected to the inlet of the three-way valve (107), the first outlet of the three-way valve (107) is connected to the first inlet of the humidifier (108), and the second outlet is connected to the first inlet of the tailpipe valve (112), the first outlet of the humidifier (108) is connected to the cathode inlet of the fuel cell stack (101), the cathode outlet of the fuel cell stack (101) is connected to the second inlet of the humidifier (108), the second outlet of the humidifier (108) is connected to the second inlet of the tailpipe valve (112), and the outlet of the tailpipe valve (112) is connected to the atmosphere, characterized in that, The exhaust structure on the electrode side of the fuel cell stack is provided on the cathode side (102), including a pressure sensor (109), an active disconnect pump (110), and a controller. The pressure sensor (109) and the active disconnect pump (110) are located on the pipeline between the first outlet of the three-way valve (107) and the cathode inlet, and are both communicatively connected to the controller.

2. The fuel cell stack electrode-side exhaust structure according to claim 1, characterized in that, The inlet of the active disconnect pump (110) is connected to the first outlet of the humidifier (108), and the outlet is connected to the cathode inlet of the fuel cell stack (101).

3. The fuel cell stack electrode-side exhaust structure according to claim 2, characterized in that, The detection end of the pressure sensor (109) is connected to the pipeline between the first outlet of the humidifier (108) and the inlet of the active disconnect pump (110).

4. The fuel cell stack electrode-side exhaust structure according to claim 1, characterized in that, An air filter (103) is also provided on the cathode side (102), with the inlet of the air filter (103) connected to the atmosphere and the outlet connected to the inlet of the air compressor (105).

5. The fuel cell stack electrode-side exhaust structure according to claim 4, characterized in that, The cathode side (102) is also provided with a flow meter (104), the inlet of which is connected to the outlet of the air filter (103) and the outlet is connected to the inlet of the air compressor (105).

6. The fuel cell stack electrode-side exhaust structure according to claim 5, characterized in that, The flow meter (104) also has a monitoring point for detecting ambient humidity.

7. The fuel cell stack electrode-side exhaust structure according to claim 1, characterized in that, The cathode side (102) is also provided with an intercooler (106), the inlet of which is connected to the outlet of the air compressor (105), and the outlet is connected to the inlet of the three-way valve (107); and / or The cathode side (102) is also provided with a tail exhaust throttle valve (111), the inlet of which is connected to the second outlet of the humidifier (108), and the outlet is connected to the second inlet of the tail exhaust valve (112).

8. The fuel cell stack electrode-side exhaust structure according to any one of claims 1-7, characterized in that, The three-way valve (107) is an electrically controlled three-way valve, and the electrically controlled three-way valve is communicatively connected to the controller.

9. A fuel cell system, characterized in that, Includes the fuel cell stack electrode-side exhaust structure according to any one of claims 1-8.

10. A method for venting the electrode-side venting structure of a fuel cell stack as described in any one of claims 1-8, characterized in that, Includes the following steps: S100, the fuel cell engine (100) is purged and the three-way valve (107) and tailpipe valve (112) are closed; S200, Set the target pressure value inside the fuel cell stack (101); S300, Adjust the speed of the active disconnect pump (110); S400: Pressure sensor (109) monitors whether the pressure value inside the fuel cell stack (101) has reached the set target pressure value. If yes, proceed to S500; otherwise, return to S300. S500, shut down the active disconnect pump (110); S600, End.

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